
[Federal Register Volume 88, Number 152 (Wednesday, August 9, 2023)]
[Proposed Rules]
[Pages 54118-54222]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-16158]



[[Page 54117]]

Vol. 88

Wednesday,

No. 152

August 9, 2023

Part V





Environmental Protection Agency





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40 CFR Parts 2 and 51





Revisions to the Air Emissions Reporting Requirements; Proposed Rule

  Federal Register / Vol. 88, No. 152 / Wednesday, August 9, 2023 / 
Proposed Rules  

[[Page 54118]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 2 and 51

[EPA-HQ-OAR-2004-0489; FRL-8604-02-OAR]
RIN 2060-AV41


Revisions to the Air Emissions Reporting Requirements

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This action proposes changes to the EPA's Air Emissions 
Reporting Requirements (AERR). The proposed amendments may require 
changes to current regulations of State, local, and certain tribal air 
agencies; would require these agencies to report emissions data to the 
EPA using different approaches from current requirements; and would 
require owners/operators of some facilities to report additional 
emissions data. More specifically, the EPA is proposing to require 
certain sources report information regarding emission of hazardous air 
pollutants (HAP); certain sources to report criteria air pollutants, 
their precursors and HAP; and to require State, local, and certain 
tribal air agencies to report prescribed fire data. The proposed 
revisions would also define a new approach for optional collection by 
air agencies of such information on HAP by which State, local and 
certain tribal air agencies may implement requirements and report 
emissions on behalf of owners/operators. The proposed revisions would 
also make the requirements for point sources consistent for every year; 
phase in earlier deadlines for point source reporting; and add 
requirements for reporting fuel use data for certain sources of 
electrical generation associated with peak electricity demand. The 
proposed revisions include further changes for reporting on airports, 
rail yards, commercial marine vessels, locomotives, and nonpoint 
sources. For owners/operators of facilities that meet criteria 
described in this proposal, the proposed revisions would require 
reporting of performance test and performance evaluation data to the 
EPA for all tests conducted after the effective date provided in the 
final rulemaking. The EPA also proposes to clarify that information the 
EPA collects through the AERR is emission data that is not subject to 
confidential treatment.

DATES: Comments on this proposed rule must be received on or before 
October 18, 2023. Under the Paperwork Reduction Act, comments on the 
information collection request must be received by the EPA and OMB on 
or before September 8, 2023.
    Public hearing: The EPA will hold a virtual public hearing on 
August 30, 2023. See SUPPLEMENTARY INFORMATION for additional 
information on the public hearing.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2004-0489, by one of the following methods:
     www.regulations.gov: Follow the online instructions for 
submitting comments.
     Email: [email protected]. Fax: (202) 566-9744.
     Mail: Air Emissions Reporting Requirements Rule, Docket 
No. EPA-HQ-OAR-2004-0489, Environmental Protection Agency, Mailcode: 
2822T, 1200 Pennsylvania Ave. NW, Washington, DC 20460. Please include 
two copies.
     Hand Delivery: Docket No. EPA-HQ-OAR-2004-0489, EPA Docket 
Center, Public Reading Room, EPA West, Room 3334, 1301 Constitution 
Ave. NW, Washington, DC 20460. Such deliveries are only accepted during 
the Docket's normal hours of operation, and special arrangements should 
be made for deliveries of boxed information.
    Instructions: All submissions received must include the Docket ID 
No. for this rulemaking. Comments received may be posted without change 
to https://www.regulations.gov/, including any personal information 
provided. For detailed instructions on sending comments and additional 
information on the rulemaking process, see the ``Public Participation'' 
heading of the SUPPLEMENTARY INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: Mr. Marc Houyoux, Office of Air 
Quality Planning and Standards, Air Quality Assessment Division, 
Emission Inventory and Analysis Group (C339-02), U.S. Environmental 
Protection Agency, Research Triangle Park, NC 27711; telephone number: 
(919) 541-3649; email: [email protected] (and include ``AERR'' on the 
subject line).

SUPPLEMENTARY INFORMATION: 
    Organization of this document. The information in this preamble is 
organized as follows:

Table of Contents

I. Public Participation
II. General Information
III. Background and Purpose of This Rulemaking
    A. Point Sources
    1. Proposed Point Source Revisions Affecting Both States and 
Owners/Operators
    2. Additional Proposed Point Source Revisions Affecting States
    3. Additional Reporting by Owners/Operators
    B. Nonpoint Sources
    1. Nonpoint Online Survey and Activity Data Requirements
    2. Commercial Marine Vessel and Locomotive Emissions 
Requirements
    3. Nonpoint Sources Reported by States and Indian Tribes
    C. Fires
    D. Mobile Sources
    E. Other Changes
IV. Proposed Revisions to Emissions Reporting Requirements
    A. Emissions Data Collection of Hazardous Air Pollutants for 
Point Sources
    1. EPA Needs HAP Emissions for Regulatory Purposes
    2. EPA Needs Emissions for Risk Assessment
    3. EPA Needs HAP Emissions for Air Quality Modeling
    4. Proposed HAP Reporting Requirements
    5. Collecting HAP Annual Emissions
    6. State Application for Voluntary HAP Reporting Responsibility
    7. Review and Revisions to HAP Reporting Responsibility
    8. Expansion of Point Source Definition To Include HAP
    9. Special Cases of Emissions Thresholds for Non-Major Sources
    10. Pollutants To Be Required or Optional for Point Sources
    11. Reporting Release Coordinates
    12. Reduced HAP Reporting Requirements for Small Entities
    13. Emissions Estimation Tool for Small Entities
    14. Definition of Small Entities
    15. Reporting HAP and CAP for the Same Emissions Processes
    16. Option To Include PFAS as a Required Pollutant
    B. Collection of Emissions From Point Sources Not Reported by 
States
    1. Facilities on Land Not Reporting Under the Current AERR
    2. Facilities Within Federal Waters
    C. Source Test Reporting
    D. Reporting for Certain Small Generating Units
    E. Provisions for Portable and Offshore Sources
    F. Reporting Deadlines for Point Sources
    1. Deadlines for States for Point Sources
    2. Annual Emissions Deadlines for Owners/Operators of Point 
Sources
    3. Summary of Reporting Deadlines and Phase-In Years
    G. Point Source Reporting Frequency
    H. Clarification About Confidential Treatment of Data
    I. Additional Point Source Reporting Revisions
    1. Formalizing the Approach for Aircraft and Ground Support 
Equipment
    2. Formalizing the Approach for Rail Yards
    3. New Requirements for Point Source Control Data
    4. New Requirements for Point Source Throughput in Specific 
Units of Measure
    5. New Requirement for Including Title V Permit Identifier

[[Page 54119]]

    6. New Requirement to Use the Best Available Emission Estimation 
Method
    7. New Requirement to Use the Source Test Reports for Emission 
Rates
    8. New Requirement To Identify Regulations That Apply to a 
Facility
    9. Existing Regulatory Requirements to be Required by EPA Data 
Systems
    10. Option for Reporting Two-Dimensional Fugitive Release Points
    11. Changes to Reporting the North American Industrial 
Classification System Code
    12. Clarification About Definition of the Facility Latitude/
Longitude
    13. Clarification to Use the Latest Reporting Codes for 
Electronic Reporting
    14. Clarification About Reporting Individual Pollutants or 
Pollutant Groups
    15. Clarification About How To Report HAP That Are Part of 
Compounds
    16. Requirement to Includes Certain Mobile Sources Within Point 
Source Reports
    17. Cross-Program Identifiers Option
    18. New Requirements When Using Speciation Profiles To Calculate 
Emissions
    19. New Requirement for Small Entity Type
    J. Nonpoint Activity Data Reporting and Nonpoint Survey
    K. Nonpoint Year-Specific Data and Timing of Reporting
    L. Nonpoint Reporting for Tribes and States With Counties 
Overlapping Indian Country
    M. Requirements for Prescribed Burning
    N. Revisions to Requirements for Agricultural Fires and Optional 
Reporting for Wildfires
    O. Revisions for Onroad and Nonroad Emissions Reporting for 
California
    P. Clarifications for Reporting Emission Model Inputs for Onroad 
and Nonroad Sources
    Q. Definition of Actual Emissions
    R. Provisions for State Implementation Plans
    1. Point Source Thresholds
    2. Detail Required by Emission Inventory Provisions of SIP 
Implementation Rules
    3. Emission Inventory Years
    S. Summary of Expected Timing for Proposed Revisions
V. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulations and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    K. Determinations Under CAA Section 307(b)(1) and (d)

I. Public Participation

    The EPA will hold a virtual public hearing on August 30, 2023. The 
hearing will convene at 10:00 a.m. Eastern Time (ET) and will conclude 
at 4:00 p.m. ET. The EPA may close the hearing 15 minutes after the 
last pre-registered speaker has testified if there are no additional 
speakers. The EPA will announce any further details at https://www.epa.gov/air-emissions-inventories/air-emissions-reporting-requirements-aerr.
    Upon publication of this document in the Federal Register, the EPA 
will begin pre-registering speakers for the hearing. The EPA will 
accept registrations on an individual basis. To register to speak at 
the virtual public hearing, please follow the instructions at https://www.epa.gov/air-emissions-inventories/air-emissions-reporting-requirements-aerr or contact the public hearing team at 919-541-3391 or 
by email at [email protected]. The last day to pre-register to 
speak at the hearing will be August 25, 2023. Prior to the hearing, the 
EPA will post a general agenda that will list pre-registered speakers 
in approximate order at https://www.epa.gov/air-emissions-inventories/air-emissions-reporting-requirements-aerr.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 4 minutes to provide oral testimony. The 
EPA encourages commenters to provide the EPA with a copy of their oral 
testimony as written comments to the rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    Any updates made to any aspect of the hearing will be posted online 
at https://www.epa.gov/air-emissions-inventories/air-emissions-reporting-requirements-aerr. The EPA does not intend to publish a 
document in the Federal Register announcing updates. While the EPA 
expects the hearing to go forward as described in this section, please 
monitor https://www.epa.gov/air-emissions-inventories/air-emissions-reporting-requirements-aerr for any updates to the information 
described in this document, including information about the public 
hearing.
    If you require the services of a translator or a special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team contact listed above and describe 
your needs by August 16, 2023. The EPA may not be able to arrange 
accommodations without advance notice.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2004-0489. All documents in the docket are 
listed in https://www.regulations.gov/. Although listed, some 
information is not publicly available, e.g., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy. With the exception of such material, publicly available docket 
materials are available either electronically in Regulations.gov or in 
hard copy at the EPA Docket Center, Room 3334, WJC West Building, 1301 
Constitution Avenue NW, Washington, DC. The Public Reading Room is open 
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal 
holidays. The telephone number for the Public Reading Room is (202) 
566-1744, and the telephone number for the EPA Docket Center is (202) 
566-1742.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2004-0489. The EPA's policy is that all comments received will be 
included in the public docket without change and may be made available 
online at https://www.regulations.gov/, including any personal 
information provided, unless the comment includes information claimed 
to be CBI or other information whose disclosure is restricted by 
statute. Do not submit electronically to https://www.regulations.gov/ 
any information that you consider to be CBI or other information whose 
disclosure is restricted by statute. This type of information should be 
submitted as discussed in the Submitting CBI section of this document.
    The EPA may publish any comment received to its public docket. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points

[[Page 54120]]

you wish to make. The EPA will generally not consider comments or 
comment contents located outside of the primary submission (i.e., on 
the Web, cloud, or other file sharing system). For additional 
submission methods, the full EPA public comment policy, information 
about CBI or multimedia submissions, and general guidance on making 
effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.
    The https://www.regulations.gov/ website allows you to submit your 
comment anonymously, which means the EPA will not know your identity or 
contact information unless you provide it in the body of your comment. 
If you send an email comment directly to the EPA without going through 
https://www.regulations.gov/, your email address will be automatically 
captured and included as part of the comment that is placed in the 
public docket and made available on the internet. If you submit an 
electronic comment, the EPA recommends that you include your name and 
other contact information in the body of your comment and with any 
digital storage media you submit. If the EPA cannot read your comment 
due to technical difficulties and cannot contact you for clarification, 
the EPA may not be able to consider your comment. Electronic files 
should not include special characters or any form of encryption and be 
free of any defects or viruses. For additional information about the 
EPA's public docket, visit the EPA Docket Center homepage at https://www.epa.gov/dockets.
    Submitting CBI. Do not submit information containing CBI to the EPA 
through https://www.regulations.gov/. Clearly mark the part or all the 
information that you claim to be CBI. For CBI information on any 
digital storage media that you mail to the EPA, note the docket ID, 
mark the outside of the digital storage media as CBI, and identify 
electronically within the digital storage media the specific 
information that is claimed as CBI. In addition to one complete version 
of the comments that includes information claimed as CBI, you must 
submit a copy of the comments that does not contain the information 
claimed as CBI directly to the public docket through the procedures 
outlined in the Instructions section of this document. If you submit 
any digital storage media that does not contain CBI, mark the outside 
of the digital storage media clearly that it does not contain CBI and 
note the docket ID. Information not marked as CBI will be included in 
the public docket and the EPA's electronic public docket without prior 
notice. Information marked as CBI will not be disclosed except in 
accordance with procedures set forth in 40 Code of Federal Regulations 
(CFR) part 2.
    Our preferred method to receive CBI is for it to be transmitted 
electronically using email attachments, File Transfer Protocol (FTP), 
or other online file sharing services (e.g., Dropbox, OneDrive, Google 
Drive). Electronic submissions must be transmitted directly to the 
OAQPS CBI Office at the email address [email protected], and as 
described above, should include clear CBI markings and note the docket 
ID. If assistance is needed with submitting large electronic files that 
exceed the file size limit for email attachments, and if you do not 
have your own file sharing service, please email [email protected] to 
request a file transfer link. If sending CBI information through the 
postal service, please send it to the following address: OAQPS Document 
Control Officer (C404-02), OAQPS, U.S. Environmental Protection Agency, 
Research Triangle Park, North Carolina 27711, Attention Docket ID No. 
EPA-HQ-OAR-2004-0489. The mailed CBI material should be double wrapped 
and clearly marked. Any CBI markings should not show through the outer 
envelope.

Expedited Comment Review

    To expedite review of your comments by agency staff, you are 
encouraged to send a courtesy copy of your comments, in addition to the 
copy you submit to the official docket, to Mr. EPA-Anonymous, U.S. EPA, 
Office of Air Quality Planning and Standards, Air Quality Assessment 
Division, Emission Inventory and Analysis Group, Mail Code C339-02, 
Research Triangle Park, NC 27711; telephone: (919) 541-3649; email: 
[email protected] and include ``AERR'' on subject line.

II. General Information

Does this action apply to me?

    Categories and entities potentially regulated by this action 
include:

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                Category                         NAICS code \a\              Examples of regulated entities
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State/local/tribal government...........  92411......................  State, territorial, and local government
                                                                        air quality management programs. Tribal
                                                                        governments are not affected, unless
                                                                        they have sought and obtained treatment
                                                                        in the same manner as a State under the
                                                                        Clean Air Act and Tribal Authority Rule
                                                                        and, on that basis, are authorized to
                                                                        implement and enforce the Air Emissions
                                                                        Reporting Requirements rule.
Major sources...........................  Any........................  Owners/operators of facilities.
Other (than major) sources..............  ...........................  Owners/operators of facilities of:
                                          21xxxx, 22xxxx, 3xxxxx       Industrial and manufacturing industries.
                                           except for 311811.
                                          4247xx.....................  Petroleum and Petroleum Products Merchant
                                                                        Wholesalers.
                                          481xxx.....................  Scheduled Air Transportation.
                                          486xxx.....................  Pipeline Transportation.
                                          4883xx.....................  Support Activities for Water
                                                                        Transportation.
                                          493xxx.....................  Warehousing and Storage.
                                          5417xx.....................  Scientific Research and Development
                                                                        Services.
                                          54199x.....................  Other Professional, Scientific, and
                                                                        Technical Services.
                                          56191x.....................  Packaging and Labeling Services.
                                          5622xx.....................  Waste Treatment and Disposal.
                                          5629xx.....................  Waste Management and Remediation
                                                                        Services.
                                          61131x.....................  Colleges, Universities, and Professional
                                                                        Schools.
                                          62211x.....................  General Medical and Surgical Hospitals.
                                          62231x.....................  Specialty (except Psychiatric and
                                                                        Substance Abuse) Hospitals.
                                          811121.....................  Automotive Body, Paint and Interior
                                                                        Repair and Maintenance \b\.
                                          8122xx.....................  Death Care Services.
                                          812332.....................  Industrial Launderers.
                                          92214x.....................  Correctional Institutions.
                                          927xxx.....................  Space Research and Technology.

[[Page 54121]]

 
                                          928xxx.....................  National Security and International
                                                                        Affairs.
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\a\ North American Industry Classification System.
\b\ Excluding small businesses for primary NAICS 811121.

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that could potentially 
be regulated by this action. Other types of entities not listed in the 
table could also be regulated. To determine whether your entity could 
be regulated by this proposed action, you should carefully examine the 
proposed revisions to the applicability criteria found in Sec.  51.1 of 
the proposed regulatory text within this action. If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed in the FOR FURTHER INFORMATION 
CONTACT section.

III. Background and Purpose of This Rulemaking

    Background: The EPA promulgated the Air Emissions Reporting 
Requirements (AERR, 73 FR 76539, December 17, 2008) to consolidate and 
harmonize the emissions reporting requirements of the oxides of 
nitrogen (NOX) State Implementation Plan (SIP) Call (73 FR 
76558, December 17, 2008, as amended at 80 FR 8796, February 19, 2015; 
84 FR 8443, March 8, 2019) and the Consolidated Emissions Reporting 
Rule (CERR, 67 FR 39602, June 10, 2002) with the needs of the Clean Air 
Interstate Rule (CAIR, 70 FR 25161, May 12, 2005). The EPA subsequently 
promulgated revisions of Subpart A (80 FR 8787, February 19, 2015), to 
align Subpart A with the revised National Ambient Air Quality Standard 
(NAAQS) for Lead (Pb) (73 FR 66964, November 12, 2008) and the 
associated Revisions to Lead Ambient Air Monitoring Requirements (75 FR 
81126, December 27, 2010), and to reduce burden on States and local air 
agencies by making minor technical corrections. On August 24, 2016, the 
EPA further revised Subpart A (80 FR 58010) with the promulgation of 
the particulate matter (PM) with an aerodynamic diameter less than or 
equal to 2.5 microns (PM2.5) SIP Requirements Rule to update 
the emissions reporting thresholds in Table 1 to Appendix A of this 
subpart.
    Under the current AERR, State, local, and some tribal agencies \1\ 
are required to report emissions of criteria air pollutants and 
precursors (collectively, CAPs) to EPA. Required pollutants under the 
current rule are carbon monoxide (CO), NOX, volatile organic 
compounds (VOC), sulfur dioxide (SO2), ammonia 
(NH3), PM2.5, PM with an aerodynamic diameter 
less than or equal to 10 microns (PM10), and Pb. Further, 
these agencies may optionally report emissions of HAP and other 
pollutants. For simplicity in the remainder of this document, the term 
``States'' will be used to denote all agencies that are currently 
reporting or that could/would report under any revision to the AERR 
(see 40 CFR 51.1(b) and (e) of this proposed action). Some facilities 
must be reported as point sources (as defined by the current AERR at 40 
CFR 51.50) based on potential-to-emit (PTE) reporting thresholds for 
CAPs and an actual emissions reporting threshold for Pb. The current 
AERR includes a lower set of point source reporting thresholds for 
every third year and, thus, States are required to report more 
facilities as point sources on these triennial inventory years. The 
remaining requirements in the current rule are for the triennial 
inventories only, for which stationary sources must be reported as 
county total ``nonpoint'' sources. Agricultural burning is included as 
a nonpoint source. States, except for California, must also provide 
inputs to the MOtor Vehicle Emissions Simulator (MOVES), while 
California must submit CAP emissions for onroad vehicles and nonroad 
equipment. States are also encouraged to participate in voluntary 
reporting of wildfire and prescribed burning activity data, such as the 
location and size of burning.
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    \1\ As prescribed by the Tribal Authority Rule (63 FR 7253, 
February 12, 1998), codified at 40 CFR part 49, subpart A, tribes 
may elect to seek treatment in the same manner as a state (TAS) 
status and obtain approval to implement rules such as the AERR 
through a Tribal Implementation Plan (TIP), but tribes are under no 
obligation to do so. However, those tribes that have obtained TAS 
status for this purpose are subject to the Subpart A requirements to 
the extent allowed in their TIP. Accordingly, to the extent a tribal 
government has applied for and received TAS status for air quality 
control purposes and is subject to the Subpart A requirements under 
its TIP, the use of the term State(s) in Subpart A shall include 
that tribe.
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    In addition to the annual and triennial reporting requirements in 
the current rule, the AERR serves as the reference for the 
NOX SIP Call (40 CFR part 51 Subpart G), Regional Haze 
requirements (50 CFR part 51, subpart P), Ozone SIP Requirements Rules 
(40 CFR part 51, subparts X, AA, and CC) and the PM2.5 SIP 
Requirements Rule (40 CFR part 51, subpart Z). These other rules point 
to the AERR to define certain requirements related to emissions 
inventories for SIPs, collectively known as SIP planning inventories.
    Purpose: The proposed amendments in this action would ensure that 
the EPA has sufficient information to identify and solve air quality 
and exposure problems. The proposed amendments would also allow the EPA 
to have information readily available that the Agency needs to protect 
public health and perform other activities under the Clean Air Act (CAA 
or ``the Act''). Further, the proposed amendments would ensure that 
communities have the data needed to understand significant sources of 
air pollution that may be impacting them--including potent carcinogens 
and other highly toxic chemicals linked with a wide range of chronic 
and acute health problems. The EPA has taken a systematic approach in 
developing this proposed action to ensure that key emissions 
information is collected in a streamlined way, while preventing 
unnecessary impacts to small entities within the communities we seek to 
inform and protect. The proposed amendments would continue EPA's 
partnership with States in a way that also respects the cooperative 
federalism framework provided by the CAA.
    Authority: Pursuant to its authority under sections 110, 172, and 
the various NAAQS-specific sections of the CAA, the EPA has required 
the preparation of SIPs to include inventories containing information 
about criteria pollutant emissions and their precursors (e.g., VOC). 
The EPA codified these inventory requirements in Subpart Q of 40 CFR 
part 51 in 1979 and amended them in 1987. The 1990 Amendments to the 
CAA revised many of the CAA provisions related to the attainment of the 
NAAQS and the protection of visibility in Class I areas. These 
revisions established new periodic emission inventory requirements 
applicable to certain areas that were designated nonattainment for 
certain pollutants. For example, section 182(a)(3)(A) required States 
to submit an emission inventory every 3 years for Moderate ozone 
nonattainment areas beginning in 1993. Similarly, section 187(a)(5) 
required States to submit an

[[Page 54122]]

inventory every 3 years for Moderate CO nonattainment areas.
    The EPA promulgated the original AERR in 2008 with the intent of 
streamlining various reporting requirements including those of CAA 
section 182(a)(3)(A) for ozone nonattainment areas and section 
187(a)(5) for CO nonattainment areas, those under the NOX 
SIP Call (40 CFR 51.122), and the annual reporting requirements of the 
CERR. The original AERR and its subsequent 2015 revision stem from 
these various CAA authorities in sections 110, 114, 172, 182, 187, 189, 
and 301(a). Likewise, the authority for the EPA to amend the reporting 
requirements for CAPs, as proposed in this action, stems from these 
same CAA provisions that the EPA relied upon to promulgate the original 
AERR and amend it in the past. The EPA is not reopening any aspects of 
the AERR except for those where we are proposing revisions or taking 
comment as described in this preamble and the accompanying draft 
regulatory text revisions.
    This proposed action would additionally require that owners/
operators of certain point sources report certain information on HAP to 
support the EPA and State needs for HAP data. Sections 114(a)(1) and 
301(a) of the CAA provide the authority for the HAP reporting 
requirements contained in this proposed action. These provisions 
authorize the EPA to collect data routinely from owners/operators of 
emissions sources and other entities for the purpose of carrying out 
the provisions of the Act.
    Section 114(a)(1) of the CAA authorizes the Administrator to, among 
other things, require certain persons (explained below) on a one-time, 
periodic, or continuous basis to keep records, make reports, undertake 
monitoring, sample emissions, or provide such other information as the 
Administrator may reasonably require. The EPA may require this 
information of any person who (i) owns or operates an emission source, 
(ii) manufactures emission control or process equipment, (iii) the 
Administrator believes may have information necessary for the purposes 
set forth in CAA section 114(a), or (iv) is subject to any requirement 
of the Act (except for manufacturers subject to certain Title II 
requirements). The information may be required for the purposes of: (1) 
developing an implementation plan such as those under sections 110 or 
111(d), (2) developing an emission standard under sections 111, 112, or 
129, (3) determining if any person is in violation of any standard or 
requirement of an implementation plan or emissions standard, or (4) 
``carrying out any provision'' of the Act (except for a provision of 
Title II with respect to manufacturers of new motor vehicles or new 
motor vehicle engines).\2\
---------------------------------------------------------------------------

    \2\ Although there are exclusions in CAA section 114(a)(1) 
regarding certain Title II requirements applicable to manufacturers 
of new motor vehicle and motor vehicle engines, section 208 
authorizes the gathering of information related to those areas.
---------------------------------------------------------------------------

    The scope of the persons potentially subject to a section 114(a)(1) 
information request (e.g., a person ``who the Administrator believes 
may have information necessary for the purposes set forth in'' section 
114(a)) and the reach of the phrase ``carrying out any provision'' of 
the Act are quite broad. The EPA's authority to request information 
extends to persons not otherwise subject to CAA requirements and may be 
used for purposes relevant to any provision of the Act. It is 
appropriate for the EPA to gather the emissions data required by this 
proposed action because such information is relevant to EPA's ability 
to carry out a wide variety of CAA provisions, as illustrated by the 
following description of the uses of such emissions data by EPA.
    The EPA's need for CAP emissions data is well documented by the 
existing records for the various past AERR rulemaking actions that are 
located in the docket for this proposed action. Since the prior AERR 
promulgation, the EPA has recognized a gap in the current AERR approach 
to collect CAP emissions from all relevant facilities. The current AERR 
imposes a requirement on States to ``inventory emission sources located 
on nontribal lands and report this information to EPA.'' 40 CFR 51.1 
(emphasis added). First, the phrase ``nontribal lands'' is not defined 
and may lead to confusion. Further, data from sources located within 
the geographic scope of Indian country (as defined by 18 U.S. C. 1151) 
are relevant for many purposes, including regional and national 
analyses to support the implementation of the Regional Haze Program and 
NAAQS for ozone and PM2.5. To address this explicit data 
gap, the EPA proposes, based on the authority provided by CAA section 
114(a), to require reporting directly from certain facilities to the 
EPA. Specifically, the EPA is proposing that facilities located within 
Indian country for which the relevant tribe does not have Treatment as 
a State (TAS) status or approval to submit emissions through a Tribal 
Implementation Plan (TIP), and which are outside the geographic scope 
of the relevant State's implementation planning authority,\3\ will 
report directly to EPA.
---------------------------------------------------------------------------

    \3\ EPA is using the phrase ``implementation planning 
authority'' in this context to reflect the fact that in some cases, 
States may administer approved SIPs in certain areas of Indian 
country. For instance, in Oklahoma Dept. of Envtl. Quality v. EPA, 
740 F.3d 185 (D.C. Cir. 2014), the D.C. Circuit held that States 
have initial CAA implementation planning authority in non-
reservation areas of Indian country until displaced by a 
demonstration of tribal jurisdiction over such an area. Under the 
D.C. Circuit's decision, the CAA does not provide authority to 
States to implement SIPs in Indian reservations. However, there are 
also uncommon circumstances where another federal statute provides 
authority for a particular State to administer an approved 
implementation plan in certain areas of Indian country, which may 
include certain Indian reservations.
---------------------------------------------------------------------------

    The EPA's need for HAP emissions data stems from CAA requirements 
that the EPA is expected to meet. For example, the EPA has many 
authorities and obligations for air toxic regulatory development under 
the many provisions of CAA section 112, including technology reviews 
pursuant to CAA section 112(d)(6), and risk reviews under CAA section 
112(f)(2). EPA's implementation of these provisions is additionally 
informed by federal policy on environmental justice, including 
Executive Order 12898, which overlays environmental justice 
considerations for the EPA to assess as part of such work. HAP 
emissions data also would be useful in further refining chemical 
speciation to better meet the Agency's responsibilities under CAA Part 
D that require air quality modeling using emissions data to support 
NAAQS implementation. VOC chemical speciation is a critical part of 
such modeling and can be informed by emissions of HAP VOC. The EPA is 
additionally authorized (and in some cases, obligated) to assess the 
risks of pollutants, which requires an understanding of both toxicity 
and exposure. The EPA Office of Air and Radiation (OAR) prioritizes 
chemicals to nominate for toxicity assessment under EPA's Integrated 
Risk Information System (IRIS) program in part based on their potential 
for exposure and hazard. HAP emissions data are used to support these 
prioritization efforts. Finally, the EPA implements compliance and 
enforcement programs per CAA sections 113 and 114(a), (b), and (d), and 
HAP emissions data would support prioritization of those compliance and 
enforcement efforts. This discussion is not a comprehensive listing of 
all the possible ways the HAP information collected under this proposed 
action would assist the EPA in carrying out any provision of the CAA. 
Rather it illustrates how the information request

[[Page 54123]]

fits within the parameters of EPA's CAA authority.
    The EPA has also identified that many air emissions sources 
operating in Federal waters are not subject to emissions reporting 
under this subpart. The CAA section 328 provides the EPA the authority 
to ``establish requirements to control air pollution from Outer 
Continental Shelf sources located offshore of the States along the 
Pacific, Artic, and Atlantic Coasts, and along the United States Gulf 
Coast off the State of Florida eastward of longitude 87 degrees and 30 
minutes (``OCS sources'') to attain and maintain Federal and State 
ambient air quality standards and to comply with the provisions of part 
C of subchapter I of [the CAA].'' To support the Agency in carrying out 
this function under the CAA, including data gathering for OCS sources, 
the EPA is proposing revisions to this subpart for owners/operators of 
such sources to report emissions data to EPA.

A. Point Sources

    With this action, the EPA proposes amendments that would ensure HAP 
emissions data are collected consistently for the benefit of 
communities across the country. Currently, the availability and detail 
of HAP emissions data vary across States, which creates a situation 
where some communities have incomplete or less accurate information 
than others, while still facing the same or greater potential risks. To 
accomplish this within the authorities provided by the CAA, the EPA 
proposes new requirements on owners/operators under CAA Part A to 
report HAP emissions directly to EPA. Consistent with provisions of the 
current version of the AERR, the EPA proposes to retain State reporting 
of CAPs under CAA Part D, retain voluntary State reporting of HAP, and 
proposes an approach by which a State may report HAP emissions on 
behalf of sources in that State. As part of these proposed revisions, 
the EPA is proposing changes to the AERR-specific definition of point 
sources that would address which sources would be required to report 
based on HAP emissions.
    To reduce the possibility of redundant or conflicting HAP emissions 
reports coming to the EPA from both States and owners/operators of 
facilities, this action proposes that States may elect to assume an 
owner/operator's responsibility for HAP reporting, provided that the 
State receives EPA approval that its HAP reporting rules satisfy the 
proposed requirements that would otherwise need to be met by owners/
operators. Requirements for owners/operators would continue unless and 
until the EPA approves the State program, at which point it would 
become a State's responsibility (i.e., State reporting would no longer 
be voluntary for that State). In such cases, the requirement for 
owners/operators to report directly to the EPA under this proposed 
action would be suspended provided that the State continued to have the 
responsibility and obligation to report the source's emissions.
    Owners/operators already report HAP to many States. To allow for 
the EPA and States to streamline reporting for owners/operators, the 
EPA proposes to require owners/operators to report to the EPA using the 
Combined Air Emissions Reporting System (CAERS). This emissions 
collection system has been developed by the EPA to streamline reporting 
from owners/operators to multiple EPA and State programs. While this 
proposed amendment would add reporting requirements on owners/
operators, CAERS can offset and even reduce total burden by providing 
owners/operators a way to report to the National Emissions Inventory 
(NEI), Toxics Release Inventory (TRI), as well as State programs. The 
EPA plans future enhancements to CAERS to share emissions data with the 
Greenhouse Gas (GHG) Reporting Program (GHGRP) and the Consolidated 
Emissions Data Reporting Interface (CEDRI), which will help owners/
operators further streamline their reporting requirements.
    This proposed action does not require States to use CAERS, but the 
EPA expects its use would help streamline emissions reporting efforts 
for facilities, prevent duplication of effort, and lessen burden on 
States for maintaining their own emissions collection systems. The EPA 
proposes that if the EPA approves a State for HAP reporting under the 
proposed option for doing so, a State would be able to continue using 
their existing emissions reporting forms and approaches provided that 
such approaches were updated to reflect any new AERR requirements. 
Depending on choices made by a State, owners/operators would either 
report to the EPA using CAERS, to the State using CAERS or a State 
system, or to CAERS for HAP and to a State system for pollutants 
required by the State.
    The EPA is aware that some current State regulations have more 
stringent HAP reporting requirements than those proposed in this 
action. Similarly, EPA anticipates that future State regulations could 
be more stringent as well. A State could require reporting by owners/
operators of facilities and for pollutants that would not otherwise be 
regulated based on this proposed action. If that occurs, a State that 
is approved to report HAP would be obligated only to report to the EPA 
those facilities and pollutants that would be required by this proposed 
action.
    The proposed amendments would also rely on reporting by owners/
operators directly to the EPA to ensure data for all pollutants are 
submitted by facilities that are outside the State's implementation 
planning authority. Most facilities of this type are located within 
Indian country and within Federal waters. Under the current AERR, 
emissions from these facilities are only reported to the EPA if a tribe 
chooses to do so, either voluntarily or through a formal TIP in which 
the tribe has accepted the AERR reporting requirements. The EPA also 
collects data from the Bureau of Ocean Energy Management (BOEM) for 
certain offshore facilities within their jurisdiction. In the current 
AERR, States do not report emissions data from federally permitted 
facilities within Indian country or elsewhere that are not regulated by 
a State. The current AERR and this proposed revision defines certain 
facilities as ``point sources'' to ensure that the EPA has detailed 
data on individual facilities when needed. The proposed amendments 
would ensure that point source facilities and their emissions are 
reported to the EPA either via the State where appropriate or by 
owners/operators. This requirement would apply regardless of whether a 
facility is located within Indian country, offshore, or other 
locations.
    A summary of requirements and major impacts compared to the current 
rule are described in three sections below: (1) proposed point source 
revisions affecting both States and owners/operators, (2) proposed 
point source revisions affecting States, and (3) proposed point source 
revisions affecting owners/operators.
1. Proposed Point Source Revisions Affecting Both States and Owners/
Operators
    The EPA proposes to require owners/operators of certain facilities 
(i.e., ``point sources'' as defined by the proposed action) to report 
annual actual emissions of HAP directly to the EPA for the NEI, and the 
EPA proposes an option for States to accept the reporting 
responsibility on behalf of owners/operators within their State. Even 
for owners/operators who also must report emissions to the TRI program, 
this proposed action would require additional sub-facility details 
necessary for air quality modeling that, in turn, would allow the EPA 
to assess local-

[[Page 54124]]

scale community impacts and devise solutions for high-risk areas.
    For States, the proposed requirement for direct facility reporting 
would provide a new option not currently available under the current 
AERR. States may opt to use HAP data provided by the EPA through CAERS 
to inform their communities instead of promulgating or revising their 
own rules to collect that data. Alternatively, a State may opt to 
create or revise its own HAP emissions reporting requirements to comply 
with the proposed requirements of this action. Regarding CAP, States 
would be required to report CAP for all facilities with emissions 
greater than or equal to CAP reporting thresholds within their 
implementation planning authority.
    This action also proposes new point source reporting requirements 
for States and owners/operators of facilities within Indian country to 
report daily activity data (i.e., fuel use or heat input) for certain 
small generating units operated to help meet electricity needs on high 
electricity demand days (HEDDs). The EPA describes a proposed 
requirement and several alternatives for which small generating units 
would need to report, with the goal of improving characterization of 
emissions associated with HEDDs. The emissions from the small 
generating units can be significant when deployed synchronously by many 
facilities and can contribute to ozone formation. To allow the EPA and 
States to have the necessary data to improve characterization of these 
emissions sources and associated air quality events, the proposed 
amendments would require States to report daily fuel use or heat input 
for certain units. These proposed changes differ from the current AERR 
because they require daily activity data for a specific type of 
equipment at facilities, whereas the current AERR only requires annual 
emissions values or, if these small generating units are not located at 
a point source, no emissions reports. Under this proposed action, 
owners/operators of facilities within Indian country would also need to 
meet the same activity reporting requirements as States.
    The EPA is also proposing that the definition of point sources 
would use the same emissions reporting thresholds for every year, such 
that States and owners/operators would report emissions for the same 
sources every year starting with the 2026 inventory year. This 
contrasts with the current requirements that use higher reporting 
thresholds for every 2 out of 3 years. This proposed requirement would 
allow communities, States, and the EPA to have the latest emissions 
data from all facilities, know whether facilities have installed 
emissions controls or taken other measures to reduce emissions, and be 
notified as soon as possible when emissions have changed. This proposed 
requirement would also ensure that States and the EPA have the most up-
to-date emissions data to make informed, timely decisions for 
regulatory and other actions.
    This proposed action would additionally distinguish portable 
facilities from mobile sources operated solely for the functioning of 
one or more stationary facilities (such as mines) and would clarify 
requirements for both types of sources. The current AERR does not 
address these types of sources specifically, and as a result, while the 
EPA has expected these sources to be included in emissions reports as 
part of the current ``all emissions'' clause of the existing 40 CFR 
51.15(a)(1), the EPA has not always received portable facility 
emissions or data about mobile sources operating at facilities. To 
improve data quality related to such sources, the EPA proposes to 
include portable facilities in the AERR-specific definition of point 
sources that are subject to emissions reporting. The EPA also proposes 
that mobile sources operating solely for the function of one or more 
stationary facilities would need to be reported with the facilities' 
emissions reports. This would impact both States and owners/operators 
of facilities that are reporting directly to EPA. The EPA additionally 
seeks comment on an option for how the EPA could define portable 
sources for reporting under this subpart.
    The current AERR has ambiguous statements regarding confidential 
data that, in the past, have been misinterpreted by States when 
reporting emissions. This proposed action would clarify the AERR 
definition of confidential data by specifically referencing provisions 
of the Act and existing law that define ``emissions data,'' identifying 
components such as load, operating conditions, and process data, and 
clarifying that such data cannot be treated as confidential by the 
States or by owners/operators when such data would be required to be 
reported by this proposed action.
    The EPA also proposes to add additional required data fields for 
point source reporting, which would affect both States and owners/
operators of facilities. First, the EPA proposes to require 
identification of all federally enforceable regulations that apply to 
each unit at certain facilities for the purpose of providing a 
repository documenting the regulations a facility has determined apply 
to its units. Such a repository would support streamlining of various 
aspects of the EPA and State activities. Second, the EPA proposes to 
require Title V permit numbers for major sources. Third, this action 
proposes to require a summed activity level for fuel use from 
combustion sources at each facility using standard units of measure for 
the purpose of preventing double counting with nonpoint emissions. 
States have the option to provide that summed data across all 
facilities for which they report emissions but would need to collect 
that data annually from their facilities to comply with this 
requirement. Finally, the EPA proposes to include several new fields to 
require States and facilities to better specify their control devices 
and impacts of those controls on reducing emissions.
    This action also proposes to add a requirement for location 
information (i.e., latitude and longitude) for stack and fugitive 
release points, which has previously been voluntary. The release point 
locations are essential to correctly model and estimate risk associated 
with HAP. The current AERR requires only a single facility-wide 
location. Both States and owners/operators would be impacted by this 
proposed revision.
2. Additional Proposed Point Source Revisions Affecting States
    The EPA proposes a new approach for States to provide emissions 
data for aircraft, ground support equipment (GSE), and rail yards for 
triennial inventory years. Many States have voluntarily provided this 
information for past triennial inventories, with the EPA providing 
landing and takeoff (LTO) data for aircraft and emissions for rail 
yards for State review and comment. This action proposes to require 
States to treat these sources as point sources and to either (1) report 
aircraft activity data (i.e., LTO data) for some or all aircraft and 
emissions from rail yards, (2) report emissions for some or all 
aircraft, GSE, and some or all rail yards, or (3) comment on and/or 
accept EPA's activity data and emissions estimates.
    The EPA also proposes a clarification that offshore facilities 
(e.g., oil platforms) within State waters be reported by States when 
such facilities meet the proposed point source reporting thresholds 
included in this action. The current AERR does not specifically 
indicate whether offshore facilities should be included or not, but the 
current AERR does require States to report ``all stationary sources.'' 
Under the current rule, however, the EPA has not consistently received 
emissions data

[[Page 54125]]

from States for these sources. Since the NEI is intended to be a 
complete dataset of all emissions sources, these omissions prevented 
complete information from being available to coastal communities and 
EPA. Therefore, this action proposes to include stationary and portable 
(e.g., floating drill rig) offshore sources (excluding commercial 
marine vessel emissions) in State waters as point sources that would be 
reported to the EPA when such sources meet the proposed emissions 
reporting thresholds in this action.
3. Additional Reporting by Owners/Operators
    Under the current AERR, use of the phrase ``nontribal lands'' in 40 
CFR 51.1 may cause confusion in attempting to identify the geographic 
areas within a State's borders for which the State should report 
emissions data. Further, the Agency does not, under the current AERR, 
receive emissions data from facilities located within Indian 
reservations except in a few cases where the relevant Indian tribe has 
an approved TIP or the tribe chooses to report voluntarily. This is 
consistent with the intended scope of reporting under the current AERR. 
Similarly, owners/operators of facilities operating in Federal waters 
are not subject to reporting. This proposal would ensure that emissions 
from facilities that meet the AERR emissions reporting thresholds would 
be reported to the EPA by owners/operators when States do not report 
them.
    The EPA additionally proposes to require owners/operators of 
facilities to report the results of stack tests and performance 
evaluations (generally, called ``source tests'') electronically to the 
CEDRI system when not otherwise reported to EPA. Source tests are 
activities that demonstrate emissions and emission rates of air 
pollutants from stationary sources though prescribed methods. 
``Electronic source test reporting'' is using CEDRI to transfer the 
results of the tests through the internet. The EPA needs these data to 
develop and improve emissions factors. Many stakeholders including 
States and industry have previously asked the EPA to improve its 
emissions factors. Likewise, in 2006, EPA's Inspector General urged the 
EPA to improve both emissions factor quality and quantity in its report 
``EPA Can Improve Emissions Factors Development and Management.'' \4\ 
To implement those recommendations, the EPA created the CEDRI and 
WebFIRE data systems; however, calculations to create revised emissions 
factors depend on test data measured at sources. By requiring reporting 
of these data to CEDRI, the EPA will be able to use the data systems as 
planned to develop and improve the emissions factors.
---------------------------------------------------------------------------

    \4\ See https://www.epa.gov/office-inspector-general/report-epa-can-improve-emissions-factors-development-and-management.
---------------------------------------------------------------------------

B. Nonpoint Sources

    The EPA proposes to revise emissions reporting by States for 
nonpoint sources (as defined in the AERR at 40 CFR 51.50) to improve 
data quality, consistency, and transparency for triennial reporting. 
These proposed revisions are based on an evolution of voluntary 
approaches that have been implemented under the current AERR and 
evaluated by the EPA while implementing the last several triennial 
NEIs. If finalized, this proposed action would make mandatory those 
currently voluntary approaches that support collaboration between 
States and the EPA on nonpoint source emissions to make the needed 
improvements.
1. Nonpoint Online Survey and Activity Data Requirements
    The EPA is proposing to add a requirement for States to complete an 
online survey about their planned submissions for nonpoint sources so 
that the EPA could anticipate the States' intentions for accepting EPA 
data or reporting their own data. Currently implemented on a voluntary 
basis, this survey greatly assists States and the EPA in the quality 
assurance (QA) that compares what States submitted to the EPA to what 
States intended to submit. The nonpoint survey also provides States a 
way to indicate for each emissions sector whether they accept the EPA 
estimates.
    The EPA is also proposing to add a requirement for States to report 
input data for EPA's nonpoint emissions tools and spreadsheet 
(hereafter referenced as ``tools''). This would allow States to meet 
nonpoint source reporting requirements by reviewing, commenting on, or 
editing EPA-provided nonpoint tool inputs. As part of this proposed 
changed, the EPA proposes that for sources with EPA tools, States can 
optionally report emissions, but if they chose to report emissions, 
States would need to include documentation of those emissions. These 
proposed changes differ from the current rule, which does not require 
the survey, emission tool inputs, or documentation, but rather requires 
States to report emissions. These proposed revisions should reduce 
burden for States when they accept EPA's data or report input data to 
nonpoint emissions calculation tools, rather than calculating and 
reporting emissions themselves. Furthermore, the EPA would be better 
equipped to perform QA in situations where State data differ from EPA 
tool default estimates and evaluate the cause and reasonableness of 
differences between State and EPA emissions estimates.
2. Commercial Marine Vessel and Locomotive Emissions Requirements
    For commercial marine vessel and underway (i.e., moving) locomotive 
emissions, the EPA proposes to add a clarifying statement about 
treating such sources as nonpoint sources for submission to the EPA 
under the AERR. The EPA also proposes to require States to report 
emissions data associated with EPA's standardized emissions calculation 
methods. States would be required to either (a) report annual emissions 
and documentation, (b) provide comment on EPA-provided data, or (c) 
accept EPA-provided data.
3. Nonpoint Sources Reported by States and Indian Tribes
    The EPA intends to retain the current requirement for States to 
report emissions for nonpoint sources for which the EPA does not have 
emissions estimation tools. However, the EPA proposes to add a 
documentation requirement for such sources, which is not included in 
the current AERR. Consistent with the current rule, this proposed 
requirement would be limited to CAP emissions, but States may also 
voluntarily submit HAP emissions for these sources.
    Regarding how States and Indian tribes should report nonpoint 
sources, the EPA proposes to add a requirement for States to include 
total activity input \5\ (including Indian country) when reporting 
nonpoint data unless a State determines that an Indian tribe reports 
nonpoint tool inputs for Indian country that overlaps with a State's 
counties. In the latter case, the EPA proposes that a State would 
exclude the activity and/or emissions within Indian country from the 
county total data reported to avoid double counting. The EPA also 
proposes to add a requirement that any Indian tribe that reports 
nonpoint tool inputs and/or emissions for nonpoint sources would report 
that data separately for

[[Page 54126]]

each county that overlaps the tribe's Indian country.
---------------------------------------------------------------------------

    \5\ Activity data varies depending on the emissions calculation 
approach and, therefore, the emissions source. Examples of nonpoint 
activity data include solvent usage for printing, number and type of 
wells for oil and gas production, vehicle miles traveled for road 
dust, and fuel consumption for nonpoint industrial, commercial, and 
institutional boilers.
---------------------------------------------------------------------------

C. Wildland Fires

    The EPA proposes to require States \6\ to report activity data for 
certain prescribed fires on State, certain tribal land (i.e., for 
tribes with TAS), private, or military lands for the purpose of data 
quality and completeness, specifically excluding prescribed fires that 
occur on non-military Federal lands. Non-military Federal lands are not 
included in this requirement due to the public availability of 
prescribed burn activity data and based on continuing discussions at 
the Congressionally mandated Wildland Fire Mitigation and Management 
Commission and Wildland Fire Leadership Council which are developing 
approaches for greater prescribed fire activity data tracking 
systems.\7\ States would report fire activity data (e.g., acres burned) 
on a day-specific basis for each broadcast and understory burn 
affecting 50 acres or more. Similarly, States would report prescribed 
fire activity data for a pile burn affecting 25 acres or more, 
including fires with both pile and broadcast or understory burning 
activity. EPA is committed to helping communities and our Federal, 
State, local, and tribal partners to manage the health impacts of smoke 
from wildland fires including prescribed fires. EPA and these partners 
view the use of prescribed fire as an important tool for reducing 
wildfire risk and the severity of wildfires and wildfire smoke. This 
proposal would help gather information needed to estimate emissions 
from prescribed burning with a goal of improving the accuracy of 
emissions estimates for these activities. The EPA also proposes to add 
a requirement that, for the purposes of data reported to EPA, man-made 
grassland fires are considered prescribed fires and not agricultural 
fires, land clearance burns, or construction fires.
---------------------------------------------------------------------------

    \6\ ``States'' is previously defined in Section III of this 
preamble to include delegated local agencies and certain tribes.
    \7\ The Bipartisan Infrastructure Law provides funding for a 
significant increase in fuels and wildfire preparedness on Federal, 
Tribal, State, and private lands to reduce wildfire risk. As part of 
the funding, effort is being made to develop more information of 
prescribed fire use from these same entities.
---------------------------------------------------------------------------

    Additionally, the EPA proposes to remove the requirement for States 
to report data for agricultural fires, which would make such reporting 
voluntary rather than mandatory. Furthermore, this action proposes that 
if States voluntarily report agricultural fire emissions, States would 
report that data as day-specific event sources rather than as annual/
county total nonpoint sources.

D. Mobile Sources

    The proposed revisions would clarify how States other than 
California can meet the current requirement to report onroad and 
nonroad emissions model inputs by submitting only select inputs. 
California would not be impacted by this proposed clarification because 
this proposed action would retain the current requirement for 
California (at 40 CFR 51.15(b)(3)) to submit emissions data from its 
own mobile models rather than model inputs. This proposed action would 
establish the following minimum model inputs to be reported: a county 
database checklist, vehicle miles traveled, and vehicle population. 
Additionally, the EPA proposes a list of other mobile model inputs that 
States can optionally provide and proposes to remove certain inputs 
from being submitted in any situation.
    The EPA also proposes to add a requirement for California to 
provide documentation regarding the onroad and nonroad emissions data 
they submit, which would describe the inputs, modeling, post-processing 
of data, and quality assurance performed by California to create the 
emissions submitted to EPA.

E. Other Changes

    The EPA proposes additional changes that impact all source 
categories. First, this action proposes to add a definition of ``actual 
emissions'' that would apply specifically to this subpart A of Part 51 
(to the AERR). The proposed definition would clarify the relationship 
between the term ``actual emissions'' and other emissions terms 
including emissions from periods of startup, shutdown, and malfunction 
(SSM). Second, this proposed action would provide language to better 
address the relationship of the requirements of this subpart to the 
requirements of the NOX SIP Call, Regional Haze 
requirements, Ozone SIP Requirements Rules, and the PM2.5 
SIP Requirements Rule.

IV. Proposed Revisions to Emissions Reporting Requirements

A. Emissions Data Collection of Hazardous Air Pollutants for Point 
Sources

1. The EPA Needs HAP Emissions for Regulatory Purposes
    The CAA HAP list includes organic and inorganic substances that 
Congress identified as HAP in the 1990 CAA Amendments, which Congress 
and EPA have revised by further legislation and administrative action. 
These HAP are associated with a wide variety of adverse health effects, 
including, but not limited to cancer, neurological effects, 
reproductive effects, and developmental effects. See the Health Effects 
Notebook for Hazardous Air Pollutants.\8\ As explained in this section, 
HAP emissions data are used extensively throughout EPA's regulatory and 
informational programs to protect public health and inform communities 
of potential risks from these pollutants.
---------------------------------------------------------------------------

    \8\ U.S. EPA, Health Effects Notebook for Hazardous Air 
Pollutants, https://www.epa.gov/haps/health-effects-notebook-hazardous-air-pollutants.
---------------------------------------------------------------------------

    The EPA has significant evidence that the current voluntary 
reporting program from States is insufficient to meet these needs, even 
when augmented by air data collection under the TRI. This evidence is 
provided by EPA's work to meet the requirements of CAA 112(f)(2) for 
Residual Risk analysis and to promulgate numerous regulatory actions. 
Historically, to ensure that the EPA had sufficient emissions data to 
complete its work, some of these regulatory actions have required 
extensive one-time data collection efforts. Such intermittent data 
collections require affected entities to take additional time and incur 
additional costs due to the often hurried, non-routine, nature of the 
requests. Consistent with the Paperwork Reduction Act, each of these 
data collections allows owners/operators to review a draft, comment on 
it, and then they are ultimately required to comply with a one-off 
collection. This sporadic approach results in owners/operators having 
to re-engage in an ad-hoc process with new requirements and 
instructions each time the EPA asks for information via the Federal 
Register and otherwise; it's an unpredictable stop-and-go process that 
requires a certain amount of ``start-up'' costs (time and resources) 
from owners/operators to understand and respond to each new request 
that may be quite different from the last.
    Complete, predictable, and routine HAP reporting would 
significantly lessen the need for these intermittent data collections, 
thus reducing the burden to owners/operators to react to such 
intermittent, one-off collections. EPA would have data about all of the 
units, processes, release points, and controls at facilities and their 
associated emissions, so that EPA would not need to implement future ad 
hoc efforts to gather such information. The data collection proposed 
here would allow owners/operators to streamline collection and 
reporting by having a

[[Page 54127]]

consistent set of data to report routinely through a standardized 
approach.
    While this ongoing collection of emissions data may ultimately have 
an overall higher burden on owners/operators as compared to sporadic 
one-time requests, this burden is at least partially offset by the 
reduction in intermittent, one-off collections. EPA would have data 
about all of the units, processes, release points, and controls at 
facilities and their associated emissions.
    Further, the EPA predicts that the burden associated with the 
collection requirements proposed here will lessen over time. The EPA 
recognizes that, just like for one-time data collections, owners/
operators will incur a ``start-up'' cost of time and resources to 
initially understand and comply with the revised AERR requirements. 
However, as owners/operators continue to comply year after year, this 
``start-up'' burden associated with compliance will diminish because 
owners/operators will already know the regulations. When a standardized 
data reporting requirement is known in advanced, it provides 
respondents the opportunity to plan ahead to most efficiently use their 
resources to obtain the information to provide in the report. This 
diminishing effect does not occur with one-time collections where each 
new collection re-triggers those ``start-up'' costs. The EPA predicts 
that the AERR approach will be more efficient in the long run. Lastly, 
even if the approach proposed here imposes a burden that is 
comparatively higher than an approach of continuous one-time 
collections, the EPA finds that the incremental burden is justified by 
all the benefits associated with this proposal that one-time 
collections do not afford.
    In addition to the reviews required under CAA 112(f)(2), CAA 
112(d)(6) requires that the EPA must complete technology reviews every 
8 years for the source categories regulated under CAA 112. Having 
current HAP emissions data to support this ongoing technology review 
requirement will facilitate future technology reviews, including both 
(a) reviewing and, if appropriate, revising the current standards for 
HAP that are regulated from the source category and (b) establishing 
standards for any unregulated HAP emissions, as required under the 
decision in Louisiana Environmental Action Network v. EPA, 955 F3d 1088 
(D.C. Cir 2020) (``LEAN''). The LEAN decision clarified EPA's 
obligation to set standards for all HAP emitted from all emissions 
points for each category of major sources when EPA conducts a 
technology review and identifies a pollutant for which no MACT standard 
had been set.
    Further, the EPA Office of Inspector General (OIG) has identified 
that EPA has inadequate emissions data and is late on RTR assessments. 
In its 2007 report, ``Improvements in Air Toxics Emissions Data Needed 
to Conduct Residual Risk Assessments,'' \9\ OIG recommended that EPA 
``establish requirements for State reporting of air toxics emissions 
data and compliance monitoring information.'' In its report, OIG also 
indicated that EPA's planned activities in response to the OIG report 
``do not sufficiently address the problems identified, and we consider 
the issues unresolved.'' More recently, in 2022, OIG issued the report 
``The EPA Needs to Develop a Strategy to Complete Overdue Residual Risk 
and Technology Reviews and to meet the Statutory Deadlines for Upcoming 
Reviews.'' \10\ While this report focuses on the time it takes for EPA 
to complete a review, rather than availability of emissions data, it is 
clear from the timetable for conducting these reviews included in the 
report that collecting emissions data is a limiting factor. The 
timeline provided shows that the time to ``collect supplemental 
information'' is between 0 to 28 months. This supplemental information 
includes identifying the facilities associated with a source category 
and collecting their emissions inventory data. The data that EPA 
proposes to collect here would help address the findings of both OIG 
reports.
---------------------------------------------------------------------------

    \9\ U.S. EPA Office of Inspector General, ``Improvements in Air 
Toxics Emissions Data Needed to Conduct Residual Risk Assessments,'' 
Report No. 08-P-0020, October 31. 2007, https://www.epa.gov/office-inspector-general/report-improvements-air-toxics-emissions-data-needed-conduct-residual-risk.
    \10\ U.S. EPA Office of Inspector General, ``The EPA Needs to 
Develop a Strategy to Complete Overdue Residual Risk and Technology 
Reviews and to Meet the Statutory Deadlines for Upcoming Reviews,'' 
Report No. 22-E-0026, March 30, 2022, https://www.epa.gov/office-inspector-general/report-epa-needs-develop-strategy-complete-overdue-residual-risk-and-0.
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    Under CAA 112(c)(5), the EPA has the authority to review the list 
of section 112 source categories and list new source categories and 
subcategories according to the statutory criteria. More current and 
extensive HAP emissions data would allow the EPA to better identify 
additional source categories and subcategories for listing. 
Furthermore, once a new HAP is listed, the EPA would need information 
about which sources are emitting it in order to develop and/or review 
regulations to address the additional HAP.
    Executive Order (E.O.) 12898 (59 FR 7629, February 16, 1994) 
directs Federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, the disproportionately 
high and adverse human health or environmental effects of their 
programs, policies, and activities on minority populations (people of 
color) and low-income populations. Part of the impact of EPA's 
regulatory actions on communities is to improve air quality by reducing 
emissions of HAP and other pollutants with local impacts. Under the 
current voluntary HAP emissions reporting program, some States submit 
extensive HAP data, while other States submit few or no HAP data. While 
the TRI air data provide some additional information on the HAP 
emitted, the facility-level resolution does not provide quantitative or 
qualitative details about the types of stack and fugitive releases and 
respective emissions totals necessary for accurate risk modeling. Thus, 
analysis quality suffers in communities without detailed data. EPA's 
proposal to collect these data would help to close the gap in 
understanding impacts of HAP and other pollutants on communities and 
will therefore assist the EPA with fulfilling the goals of Executive 
Order 12898.
2. The EPA Needs HAP Emissions for Risk Assessment
    To be able to assess risks, the EPA develops information about 
pollutant toxicity and characterizes pollutant hazards under the IRIS 
program. Given the huge number of chemicals released to the air, it is 
necessary to prioritize which pollutants are investigated by the IRIS 
program. OAR uses information on emissions and exposures to help inform 
priorities for IRIS nominations, which requires detailed HAP data and 
release parameters that are not sufficiently available under the 
current voluntary program.
    The EPA has developed nationwide risk information for all 
pollutants with the National Air Toxics Assessment (NATA) program. NATA 
has been available approximately every 3 years since 2002 (starting 
with the 1996 inventory year) and has been cited in countless 
publications. More recently, as part of the air toxics strategy of the 
Office of Air Quality Planning and Standards (OAQPS), the NATA program 
has been replaced and enhanced by EPA's new AirToxScreen,\11\ which 
will provide annually updated risk and emissions information for use by 
EPA, States, and the public. AirToxScreen

[[Page 54128]]

supports more efficient implementation of numerous other programs and 
provides risk information for communities through EJSCREEN and an EPA 
website. As highlighted in the ``Our Nation's Air'' 2022 Trends 
Report,\12\ identifying areas of concern impacted by air toxics 
emissions is critical to EPA's mission to protect human health and the 
environment and that sharing the latest air toxics emissions data and 
risk are part of this effort. When EPA has more complete, current, and 
high-quality emissions data, this supports improved completeness and 
quality of this risk information.
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    \11\ U.S. EPA Air Toxics Screening Assessment, https://www.epa.gov/AirToxScreen.
    \12\ U.S. EPA Our Nation's Air Trends though 2021, https://gispub.epa.gov/air/trendsreport/2022/#home.
---------------------------------------------------------------------------

    For compliance purposes, EPA also uses the raw emissions data to 
confirm that facilities are in the proper regulatory category to ensure 
that their inspection frequency is correctly matched to their emissions 
footprint. EPA staff compares NEI data to ambient data from nearby air 
monitors to find discrepancies between the two. If a monitor is picking 
up high pollutant concentration levels for a HAP and no nearby 
facilities are reporting emissions of that HAP, EPA may find a 
reporting issue or illegal manufacturing and follow up with an 
inspection. EPA inspectors can search the EPA's Enforcement and 
Compliance History Online (ECHO) database \13\ (that includes NEI data) 
by emissions processes to help identify facilities of interest by 
industry. EPA also uses AirToxScreen and its predecessor NATA for 
prioritization of compliance and enforcement resources. Within EPA, 
compliance staff have access to the ECHO Clean Air Tracking Tool 
(ECATT), which includes data from many sources including AirToxScreen. 
This tool integrates several data sources to facilitate analysis, 
including searching for facilities based on cancer risk and respiratory 
hazard index. Likewise, the EPA regional offices and States use risk 
data to determine communities and facilities for review. The current 
voluntary HAP data collection approach has provided some of the 
information needed for this evaluation; however, a more comprehensive 
HAP emissions collection program would further enhance the 
prioritization by supporting more complete and more detailed risk and 
emissions data than are currently available.
---------------------------------------------------------------------------

    \13\ EPA Enforcement and Compliance History Online (ECHO), 
https://echo.epa.gov/.
---------------------------------------------------------------------------

    Another use of risk information enabled by HAP emissions data is 
the siting of ambient monitors. HAP emissions and risk data are used by 
the EPA and States to prioritize ambient monitor locations. These 
ambient monitors in turn inform communities about air quality in their 
local areas as well as support the evaluation of models that further 
improve available information to EPA, States, and communities.
    In addition to supporting risk assessments, the data that EPA is 
proposing to collect provides foundational information about air 
emissions for other purposes across the government. For example, 
collecting data on air pollutants that are known cancer drivers will 
advance core public health goals, including the President's Cancer 
Moonshot Initiative which has the goal of preventing cancer through 
reducing environmental exposures to carcinogens.
3. The EPA Needs HAP Emissions for Air Quality Modeling
    HAP emissions data not only inform the regulatory and programmatic 
activities dealing primarily with these pollutants, but also provide 
benefits to modeling needs for implementation of the NAAQS. Under CAA 
sections 110, 172, 182(b) through (e), and 189(a) and (b), the EPA and 
States have requirements to use air quality modeling to help bring into 
attainment nonattainment areas that violate the NAAQS ambient air 
pollutant thresholds. Increasingly, the science suggests that some HAP 
play important roles in air chemistry leading to formation of ozone and 
secondary organic aerosol (SOA), a component of PM2.5.\14\ 
For example, HAP such as formaldehyde, acetaldehyde, 1,3-butadiene, 
naphthalene, and chlorine contribute to ozone formation while other HAP 
such as toluene, xylenes, benzene, and ethyl benzene are important for 
SOA formation. In addition, some lower volatility or semi-volatile 
compounds that contribute to SOA formation are HAP, such as naphthalene 
and benzo(a)pyrene. Having more complete HAP data will be beneficial to 
improving modeling and understanding of ozone and PM2.5 
concentrations and SOA formation. The HAP data can provide the 
additional details needed to improve air quality modeling needed for 
NAAQS purposes.
---------------------------------------------------------------------------

    \14\ Carter, W. Updated Maximum Incremental Reactivity Scale and 
Hydrocarbon Bin Reactivities for Regulatory Applications, College of 
Engineering Center for Environmental Research and Technology, 
University of California, Riverside, January 28, 20210.
    Ng, N.L., Kroll, J.H., Chan, A.W.H., Chhabra, P.S., Flagan, 
R.C., and Seinfeld, J.H.: Secondary organic aerosol formation from 
m-xylene, toluene, and benzene, Atmos. Chem. Phys., 7, 3909-3922, 
https://doi.org/10.5194/acp-7-3909-2007, 2007.
    Chan, A.W.H., Kautzman, K.E., Chhabra, P.S., Surratt, J.D., 
Chan, M.N., Crounse, J.D., K[uuml]rten, A., Wennberg, P.O., Flagan, 
R.C., and Seinfeld, J.H.: Secondary organic aerosol formation from 
photooxidation of naphthalene and alkylnaphthalenes: implications 
for oxidation of intermediate volatility organic compounds (IVOCs), 
Atmos. Chem. Phys., 9, 3049-3060, https://doi.org/10.5194/acp-9-3049-2009, 2009.
---------------------------------------------------------------------------

    As part of NAAQS implementation, the CAA specifically identifies 
VOCs as a precursor to ozone, and VOC is additionally a precursor to 
PM2.5. Thus, emissions and anticipated reductions of VOC are 
inputs used for certain air quality modeling. VOC is a large group of 
individual compounds, some of which are HAP and knowledge of those 
detailed HAP compounds can be beneficial to air quality models that 
rely on the components of VOC for model chemistry. Currently, the EPA 
and States must make assumptions about the composition of VOC for each 
source using other data called speciation profiles, which are costly to 
collect, are not available for each source type, and can become 
outdated quickly as new technologies and industrial chemical 
formulations are used. In addition, new photochemical modeling chemical 
mechanisms are being developed that provide better resolution to HAP 
species. For example, the Community Regional Atmospheric Chemistry 
Multiphase Mechanism (CRACMM) explicitly simulates 1,3-butadiene and 
toluene and can also represent polycyclic organic matter and xylenes 
better than prior, commonly used chemical mechanisms. While the use of 
speciation profiles is useful, VOC speciation for modeling could be 
significantly improved with complete and accurate HAP emissions that 
provide details about the component VOC HAP.
    As with VOCs, PM2.5 is a NAAQS pollutant and is 
currently collected from States by the AERR. PM2.5 is also a 
large group of individual compounds, some of which are HAP. Individual 
HAP metals are included in this group, and some of these metals are 
required specifically in the most recent chemical formulations used in 
air quality models. In addition, as with VOCs, having more detail about 
PM2.5 components would allow for increased confidence in 
EPA's air quality modeling results.
    The EPA estimates costs and benefits as part of Regulatory Impact 
Analyses (RIAs) for rulemaking to support implementation of Executive 
Order 12866. That benefit analysis can include the ancillary benefits 
of HAP reductions, even when regulations are specific to NAAQS 
implementation. For

[[Page 54129]]

example, the RIA accompanying the revision of an ambient standard and 
revisions to national mobile source standards can describe ancillary 
benefits of HAP reductions, even when those regulations are being put 
in place to reduce VOC or PM2.5 emissions. A complete and 
integrated HAP emissions inventory would enhance EPA's ability to 
estimate the ancillary benefits of HAP reductions, and thereby help 
lead to better informed decision-making.
4. Proposed HAP Reporting Requirements
    In previous rulemakings, the EPA has considered, but never 
finalized, mandatory HAP reporting to collect emissions inventories. On 
May 23, 2000, the EPA proposed to collect HAP emissions data (CERR; 65 
FR 33268). However, the CERR proposed rule did not specify any details 
about how the EPA would collect that data, or even which pollutants the 
EPA would require to be reported. The EPA did not finalize any 
mandatory reporting for HAP due to comments received on the proposed 
rule arguing that ``EPA should not include HAP reporting requirements 
in the final rule until the specific HAP reporting requirements were 
proposed'' (67 FR 39602, June 10, 2002).
    In response to the original AERR proposed rule (71 FR 69; January 
2, 2006), several commenters encouraged the EPA to include a specific 
requirement in the rule for reporting HAP emissions data for title V 
facilities. Another commenter encouraged the EPA to include 
requirements for reporting of HAP from all emission sources. One 
commenter noted that States were attempting to provide HAP data to the 
EPA by relying on data collected from facilities largely on a voluntary 
basis, and that collection would improve if the EPA required HAP 
reporting. However, the EPA did not include HAP in the final AERR rule 
at that time. The EPA cited the existing voluntary program, stating 
that we believed it would be possible to continue developing and 
improving national level HAP inventories using a voluntary approach. We 
also explained that we intended to closely monitor the participation of 
State agencies in this effort and that, should the need arise, we would 
revisit the issue.
    Furthermore, while the EPA has numerous regulations on industrial 
facilities through the National Emission Standards for Hazardous Air 
Pollutants (NESHAP) and other similar standards, these regulations do 
not typically require the reporting emissions of annual HAP. Rather, 
they largely require reporting of compliance information such as stack 
test results. In many cases, these stack tests are not required to be 
tests for HAP but instead can be tests of a surrogate pollutant such as 
filterable PM2.5. The result of the test does not estimate 
annual emissions but rather provides an emission rate of one or more 
pollutants from the source. As a result, even for these well-regulated 
industries, the EPA lacks annual HAP except when it is voluntarily 
reported or collected for the TRI.
    With this action, the EPA is proposing to require the reporting of 
HAP from point sources, as defined by the AERR, which can be both major 
sources and non-major sources. For purposes of the AERR, certain non-
major sources can be point sources that would be subject to the 
proposed reporting requirements. These can include CAA section 
112(c)(3) area sources and sources that do not have a source category 
listing. Non-major sources would need to emit at or above the proposed 
thresholds in order to be subject to these proposed reporting 
requirements. For CAP and HAP major sources, the EPA proposes a 
requirement to report all HAP, which is defined by pollutants listed in 
CAA 112(b)(1), 42 U.S.C. 7412(b)(1) and 40 CFR 63.64(a). The EPA also 
proposes a requirement to report certain HAP from non-major sources 
\15\ when annual actual emissions exceed a reporting threshold 
promulgated by the Agency (as described in section IV.A.8 of this 
preamble and as listed in the proposed Table 1B to Appendix A of 
Subpart A). In addition to these requirements, this proposal includes 
maintaining the current voluntary pollutant reporting by States and 
industry for additional facilities and/or additional HAP for non-major 
sources and voluntary GHG reporting by States. Finally, while the 
proposal for mandatory HAP reporting is organized within the AERR 
structure for convenience and to limit burden via streamlining, the HAP 
reporting requirements are able to stand on their own separate from the 
CAP reporting requirements.
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    \15\ Non-major sources are stationary sources that do not meet 
the major source thresholds for criteria pollutants and HAP. Major 
sources require Title V permits. Criteria for these sources are 
provided at https://www.epa.gov/title-v-operating-permits/who-has-obtain-title-v-permit.
---------------------------------------------------------------------------

    Requirements for HAP reporting are being proposed for two 
overarching reasons in addition to the other reasons discussed 
throughout this notice. First, the EPA has monitored the collection and 
reporting of HAP information from States and has found that the 
voluntary approach has not sufficiently provided the EPA with the point 
source HAP data it needs. States report to the EPA between 1 and 148 
HAP per year from point sources. This proposed action would collect 
information on all 188 HAP from major sources and significant emissions 
of HAP from non-major sources. Collecting information on all HAP from 
major sources supports requirements of CAA section 112, which includes 
a definition at CAA 112(a)(1) of major HAP sources based on total HAP 
emissions, and which directs EPA at CAA 112(d)(1) to promulgate 
regulations establishing emission standards that CAA 112(d)(2) requires 
the maximum degree of reduction in emissions for all of the HAP subject 
to section 112 of the Act that are emitted from source categories of 
major sources.
    For the 2017 NEI,\16\ 76 out of 85 State/local/tribal agencies 
reported point source HAP to EPA. These 76 agencies reported an average 
of 79 such pollutants. The EPA has found these voluntary reports to be 
insufficient and, therefore, they have been unable to meet EPA's needs 
for implementing CAA section 112. Because the section 112 regulatory 
work requires the most detailed HAP emissions data, we can reasonably 
conclude that the data for other HAP analysis products and needs 
described above are similarly incomplete. While the EPA has 
increasingly used TRI air emissions data to help fill reporting gaps 
for some uses of the NEI (e.g., national totals), these data do not 
have the sufficient detail necessary for detailed risk modeling and 
other assessment needs previously described.
---------------------------------------------------------------------------

    \16\ U.S. EPA, 2017 National Emissions Inventory, https://www.epa.gov/air-emissions-inventories/2017-national-emissions-inventory-nei-data.
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    Second, the EPA now has a proven infrastructure through CAERS to 
support centralized collection of detailed emissions data from 
facilities and to provide flexibility in reporting from either 
facilities or States. CAERS can implement the requirements of this 
proposed rule without undue burden on facilities or States by: (1) 
avoiding duplicative reporting requirements, (2) supporting consistency 
of data across programs, and (3) supporting States, locals, and Indian 
tribes that collect HAP data.
    Using CAERS, the EPA is currently working to connect the CEDRI 
source test data collection with the estimation of emissions data 
included in this proposal. This proposal does not require any new 
monitoring or source testing, rather the EPA is proposing that owners/
operators use the ``best available'' estimation techniques (see section 
IV.I.6 of this preamble for more details). Through planned CAERS

[[Page 54130]]

enhancements, owners/operators would be able to pull in their source 
test data more easily, to facilitate this approach for using the best 
available data to estimate emissions. If a source is already required 
to report compliance information, such as stack testing, due to an 
existing requirement separate from the AERR, such as a NESHAP, then 
this proposal is that the owner/operator would use that existing 
information, if appropriate, for purposes of estimating annual 
emissions reported under the AERR. Similarly, if the source already 
generates certain data for the TRI, then EPA is proposing that the 
source utilize that existing data for purposes of the AERR.
5. Collecting HAP Annual Emissions
    Based on the numerous needs for HAP data described above, the EPA 
is considering how to obtain the HAP emissions data that the Agency 
needs to carry out the requirements of the CAA, while also seeking to 
minimize burden on States, by investigating whether HAP emissions 
should be reported by States, by owners/operators of facilities, or by 
some combination. The EPA's primary proposal would use a combined 
approach for reporting HAP emissions. First, this action proposes that 
owners/operators of facilities would be required to report facility 
inventory data and HAP emissions directly to the EPA via CAERS. This 
proposed approach would include reporting by facilities both within 
States and within Indian country. Second, this action proposes an 
option that would allow a State to report HAP data to the EPA on behalf 
of the owners/operators of facilities in the State. However, to 
implement this option, the EPA also proposes that States choosing to 
report HAP emissions on behalf of sources would be required to receive 
EPA approval for State regulations that implement HAP reporting 
requirements. For a State to receive approval, State regulations would 
need to meet any finalized requirements based on this proposed action 
(e.g., by reporting at least the same information from the same sources 
on the schedule required for owners/operators). State regulations could 
include additional HAP reporting requirements that exceed the EPA 
requirements. Additional details on the approach for transfer of 
responsibility from owners/operators to States is proposed below.
    The current AERR supports voluntary reporting of HAP by States. To 
date, the EPA has observed the benefit of State oversight given the 
States' authority to issue and manage permits and associated emissions 
limits. The EPA also recognizes the additional burden that would be 
placed on States if they were required to report HAP, especially for 
those States that are not already requiring such reporting from 
sources. Further, States that are already collecting HAP data may need 
to revise their current reporting rules and/or develop new collection 
mechanisms for HAP if their current programs are not meeting any final 
HAP reporting requirements that are promulgated in this rulemaking. 
This burden could include managing reports from more facilities, 
maintaining more data, and implementing a more complex annual 
collection process than a program that requires CAPs alone. The EPA 
recognizes that States will have differing capacities to include HAP 
emissions collection as an additional responsibility.
    In formulating this proposal, the EPA is considering the 
significant differences between CAA Part D, with many emission data 
provisions required of States, as compared to other provisions in CAA 
Part A under which the EPA has regulated HAP. The current AERR requires 
emissions reporting only for CAPs but does not specifically include a 
requirement for States to have reporting rules in place. This is 
because for CAPs, the CAA has set up a coregulator paradigm by which 
State emissions reporting rules are reviewed and approved by the EPA as 
part of infrastructure and other SIPs. In this way, the EPA can ensure 
that State regulations meet the various emissions reporting 
requirements of the AERR. The CAA does not provide a similar paradigm 
for HAP emissions data collection. Thus, EPA's proposed solution 
addresses these differences to provide an implementation that aligns 
with the Act.
    Another consideration is the available technical methods by which 
the EPA can gather data from States and/or from owners/operators. Under 
the current AERR, States submit data through the Central Data Exchange 
(CDX) to the Emissions Inventory System (EIS), and that approach is 
expected to continue under this proposed action. In addition, the EPA 
and States have developed CAERS as one approach for supporting State 
collection of emissions in a way that can reduce the burden on some 
owners/operators of facilities for shared reporting of emissions to the 
TRI program.
    The EPA is considering that some owners/operators of facilities are 
already obligated to report HAP to the TRI, though with less detail 
than is needed by the EPA for risk assessment and other purposes cited 
in this proposal. Because CAERS offers owners/operators a means to 
report air emissions to States, NEI, and TRI, EPA's experience leads 
the Agency to anticipate that CAERS would ultimately lessen the 
reporting burden on owners/operators. The EPA is aware that facility 
definitions occasionally differ among the TRI program, the NEI, and the 
State programs. Ongoing work by the EPA is expected to address the 
challenges posed by differing facility definitions across emissions 
collection programs, which is related to the Cross-Program Identifiers 
Option described in section IV.I.17 of this preamble.
    The EPA is also considering that there are numerous State HAP 
emissions collection programs with differing requirements. Comparing 
such programs reveals that they collect different data fields, have 
different emissions reporting thresholds, and collect different 
pollutants. Companies that operate facilities in multiple States and 
report emissions data from a central part of the company could have to 
comply with numerous different requirements depending on the State. 
Additionally, the EPA is considering that owners/operators would face 
additional challenges if a State required owners/operators to report 
HAP, but the State requirements did not match EPA requirements. In this 
case, owners/operators could be faced with the burden to report 
differently both to the State and to EPA. Indeed, this situation 
already exists with respect to State HAP requirements and EPA 
requirements for TRI reporting.
    By proposing CAERS as the reporting system for owners/operators of 
facilities, the EPA also provides States a choice about the degree to 
which the State will take on additional burden. States may choose to 
participate voluntarily in review of HAP data provided by owners/
operators to the EPA rather than implement their own reporting 
requirements. States may alternatively choose to implement HAP 
reporting regulations that match (or go beyond) EPA's requirements.
    This proposed action does not eliminate the possibility that 
industry may face a duplicative reporting requirement for the State. 
States are free to use a data collection approach of their choice and 
implement regulations that meet State needs. For example, if a State 
chooses for owners/operators of facilities to continue to report to a 
State system and those facilities are also required to report HAP to 
the EPA via CAERS, then duplication could exist. This duplication could 
take the form of requiring the same HAP emissions data be reported via 
two separate collection

[[Page 54131]]

mechanisms to both the State and to EPA. This proposal provides 
mechanisms to avoid duplicative reporting requirements, but the Agency 
is aware that it may not completely eliminate the possibility of 
duplicative requirements because it provides States choices in how they 
comply with the proposed requirements. The EPA seeks comments on how we 
might reduce or eliminate the possibility of duplicative requirements.
    While CAERS provides a way to help eliminate the possibility of 
duplicative burden on owners/operators, the EPA is not proposing to 
require that CAERs be used by States at this time. To avoid duplicative 
reporting burden for the owners/operators of facilities for which the 
associated State is collecting HAP emissions, a State would need to 
choose to participate in CAERS using one of the supported approaches. 
First, a State may choose to have owners/operators report data through 
CAERS to the EPA and then use CAERS to review and/or transfer the data 
to the State's own data system. Second, a State may choose to work with 
the EPA to build a direct connection between the State's data system 
and CAERS, so that data transfers can happen even more easily. Third, a 
State may choose to adopt CAERS as their emissions data reporting 
system.
    The EPA is considering the additional complexity that would be 
created under a requirement in which owners/operators reported HAP 
directly to the EPA while States reported CAPs to EPA. Furthermore, the 
EPA expects additional complexity because some State requirements 
would, as they do under the current AERR, collect more facilities and/
or pollutants than EPA requirements that may be finalized under this 
proposed action. To be able to support this complexity, CAERS would 
share the ``facility inventory'' among EPA, States, and owners/
operators to provide the collection of facilities and their components 
for which emissions are reported. These components include units, 
processes, release points, control devices and associated 
identification codes and parameters. The EPA is aware that often the 
identification codes for the components of the facility inventory are 
different between the State and the facility reporting the data. Thus, 
the EPA and State implementation of any finalized data collection 
approach would consider and address these challenges. The EPA requests 
comments that offer suggested approaches for sharing facility inventory 
data between the EPA and States.
    The EPA is considering whether it would be feasible to allow States 
to report only some of the required HAP, while sources retain the 
obligation to report the remaining HAP. EPA's experience suggests that 
such an approach would be too complicated to implement because it would 
require EPA and States to track reporting responsibility individually 
for the hundreds of required pollutants. The approach proposed by the 
EPA provides for a simpler tracking approach with just two categories 
of pollutants: ``CAP'' and ``HAP.'' This straightforward approach helps 
ensure that the EPA and States will know whether the State or owner/
operator is expected to report HAP for a given facility and inventory 
year. The approach also allows the EPA to administer the reporting 
program more robustly, including assessing completeness of data 
submissions and compliance with the proposed requirements. This 
proposed approach also makes it easier for owners/operators and States 
to know which party is responsible for reporting each pollutant to EPA.
    The current AERR includes voluntary reporting of HAP, air toxics, 
and greenhouse gases. As just described, the EPA proposes that the HAP 
reporting would become mandatory under any final version of this 
proposed action and proposes to retain voluntary reporting by States as 
an option in other cases. For example, States would be able to continue 
to report any pollutant for facilities not required to report for HAP 
under any final action. Additionally, for any point sources, States 
would be able to report any other pollutant not required by any final 
version of this proposed action, such as other air toxics that are not 
HAP (e.g., Tert-butyl Acetate) and greenhouse gases, provided that the 
pollutant is supported by EPA's electronic collection approach.
    In addition to the proposed policies just described, the EPA is 
considering an alternative (Alternative A1) that would not collect data 
directly from owners/operators of facilities within the geographic 
scope of a State's implementation planning authority but would only 
collect such data from States. Such an approach would reduce 
complexity, but also would not provide States flexibility in their 
implementation approach and would cause additional burden for all 
States if the EPA finalizes mandatory HAP reporting. To implement such 
an option, the EPA would change the proposed regulation as follows: 
remove owner/operator requirements of proposed Sec.  51.25(a), remove 
the HAP reporting application of proposed Sec.  51.1(d), and modify 
proposed Sec.  51.15(a)(2) to eliminate the qualifier ``if the EPA has 
approved a HAP reporting application as per Sec.  51.1(d)(2) of this 
subpart.'' The EPA requests that commenters provide input on 
Alternative A1.
    In addition, the EPA is considering a second alterative 
(Alternative A2) of relying only on owner/operator reporting for HAP 
and not including an option for States to report on behalf of owners/
operators. The existing state-reporting paradigm in the current AERR is 
a valuable approach that would continue under this alternative for CAPs 
to ensure the collection and sharing of data needed for NAAQS 
implementation under CAA Part D. For HAP, the EPA recognizes the 
benefit of States' roles in collection of HAP emissions and, for that 
reason, has proposed to include State reporting as an option. To 
implement Alternative A2, the EPA would remove the HAP reporting 
application of the proposed Sec.  51.1(d) and remove the proposed Sec.  
51.15(a)(2). In addition, under this alternative, States would continue 
to report Pb for point sources meeting any of the CAP emissions 
reporting thresholds (including Pb), while owners/operators would 
report Pb for other sources that do not meet the CAP Pb reporting 
threshold but are otherwise subject to the proposed Pb reporting 
requirements as a HAP.
    Because the primary proposed approach would require owners/
operators to report to the EPA using CAERS, the EPA anticipates that 
some States will choose to participate in the CAERS program. In 
addition, the EPA has already received notifications from States of 
their intent to adopt CAERS in some form, and the EPA recognizes a need 
for managing that process so that the EPA and States will have 
sufficient time to transition to CAERS in advance of emissions data 
collection. To address these considerations, the EPA proposes that 
States voluntarily adopting one of the CAERS workflows notify the EPA 
within 2 months before the beginning of the first inventory year for 
which a State intends to use the CAERS workflow. For example, for the 
2024 inventory year, a State would notify the EPA by November 1, 2023. 
This timing would allow the EPA and the State about 16 months to 
integrate the States' needs and data to CAERS in preparation for the 
start of the CAERS reporting period for that inventory year by February 
of the year after the inventory year.\17\ For

[[Page 54132]]

example, for the 2024 inventory year, the EPA would make available 
CAERS no later than February 28, 2025, for owners/operators to report 
emissions data. While such a notification is included in the proposed 
rule as a recommendation (i.e., ``should'') rather than a requirement, 
if a State does not notify the EPA in advance of that date, the EPA may 
not be able to accommodate the State for CAERS use until the following 
inventory year.
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    \17\ The availability of each CAERS release to date has been 
during February of each year, with CAERS opening for reporting for 
the 2022 inventory year on February 6, 2023.
---------------------------------------------------------------------------

6. State Application for Voluntary HAP Reporting Responsibility
    With HAP emissions reporting by either owners/operators or by 
States for a particular inventory year, it is necessary that this 
proposed action include provisions to ensure that EPA, States, and 
owners/operators all know which party is expected to report HAP 
emissions to EPA. Under this proposal, a State could choose to report 
for all owners/operators within the State who would have to report HAP. 
This proposed approach allows for States that already report HAP to 
continue to do so, but also avoids a burden increase for other States 
while making CAERS available to further reduce burden for States 
reporting HAP.
    A clear and documented transfer of responsibility from owners/
operators to a State is necessary when a State elects to report HAP, 
and the EPA is considering how best to ensure that the State 
regulations provide an adequate substitute for its own requirements in 
this situation. Similarly, this proposed action includes an approach to 
transfer responsibility from a State back to sources in the event a 
State no longer meets the requirements or intends to stop reporting on 
behalf of owners/operators.
    The EPA is considering how States should document their intent to 
meet this proposed action's HAP reporting requirements. One approach 
under consideration could be to have States simply notify the EPA of 
their intent, and if the State did not fulfill a reporting requirement, 
require the facility to report any missing data to EPA. This approach 
has the benefit of more flexibility, but implementation would be very 
challenging because it would not be clear which party would be 
obligated to report which data. Further, turning to owners/operators to 
report when States have missed the requirement would delay the data 
transmission to EPA.
    To provide the EPA with evidence of a State's intent and to ensure 
a clear transfer of responsibility from an owner/operator to a State, 
the EPA proposes to require that a State choosing to report on behalf 
of its owners/operators adopt EPA's requirements, or the equivalent, 
into the State's regulations. This proposed action also specifies the 
process for the transfer to occur, including State submittal of its HAP 
emission collection program to the EPA for approval. When a State 
submits its program, the submittal would reference the State regulation 
and explain how it meets all provisions of EPA HAP reporting 
requirements. Without a sufficient State regulation, the EPA would not 
be able to approve a State to report HAP emissions on behalf of owners/
operators. The EPA recognizes sufficient time is required for changes 
to State regulations, which informs the proposal of 2026 as the first 
inventory year that would require HAP reporting by owners/operators 
within States.
    The EPA proposes that the geographic scope of a State regulation 
requiring HAP emissions data should be consistent with those lands 
covered by the State's Infrastructure SIP (EPA understands this scope 
to be synonymous with the relevant State's implementation planning 
authority). This proposed approach stems from the current structure of 
the AERR and this proposal's approach to continue States' reporting of 
CAP emissions data for sources located within this geographic scope. 
The intent is to create clarity regarding which parts of a State's 
geographic boundaries would be included for HAP reporting by the State 
under this proposal, and the EPA's understanding of the State's 
authority would generally be the same for sources of CAP and HAP 
emissions. Once a State is approved to report HAP emissions on behalf 
of the owners/operators of facilities located within the geographic 
scope of the State's implementation planning authority, then the State 
becomes the responsible party for complying with the requirements of 
the AERR for those sources; the EPA would no longer consider those 
owners/operators to be the party responsible for compliance.
    To formalize the transfer of responsibility for reporting after the 
completion of the process described above, the EPA would issue a letter 
to the State indicating that the State is approved to submit HAP 
reports on behalf of owners/operators. Further, to provide a means for 
owners/operators to determine whether their State has assumed the 
responsibility for reporting, the EPA would post that letter on a 
website that would be maintained for the purpose of communicating which 
States are responsible to report HAP on behalf of owners/operators for 
each inventory year.
    The EPA additionally proposes to require a State seeking approval 
to submit its HAP collection program to the EPA by March 31 of the 
first inventory year for which the State intends to report emissions 
(e.g., by March 31, 2026, for the 2026 inventory year). This timing is 
designed to be at least one year in advance of the deadline proposed 
for owners/operators to report emissions directly to EPA. It provides 
sufficient time for the EPA to review the State application, the State 
to revise the application if needed, and the EPA to act on the State 
submittal. A State could still submit after this deadline but doing so 
would likely mean that the transfer of authority would not happen in 
time for the next reporting period. A delayed application would simply 
delay when the State could start reporting if approved. Once the EPA 
provides HAP reporting approval, the State would be obligated to 
fulfill the HAP reporting requirements for subsequent inventory years. 
While the EPA will make every effort to review applications in time for 
the desired inventory reporting year, there is no guarantee that the 
EPA will complete the review in time to meet the States' wishes.
    The EPA would notify States as expeditiously as possible regarding 
EPA's response to the State's application, any needed adjustments, and 
post final decisions on the EPA Air Emissions Inventories website. This 
website publication would ideally be made by December 15 of the 
inventory year, but the date could be earlier or later than that 
depending on circumstances. This target date is intended to provide 
sufficient time for owners/operators to adjust plans and obtain 
training for any new reporting systems. Since States start collecting 
data within months of this date, the EPA expects States would have 
already made updates to their data collection system to comply with 
their new regulatory requirements in advance of this date in 
anticipation of approval.
7. Review and Revisions to HAP Reporting Responsibility
    The EPA proposes to require an EPA review of previously issued HAP 
reporting approval when: (1) a State or the EPA revises emissions 
reporting requirements for any emissions data element affecting HAP 
(including the facility inventory); or (2) the EPA is made aware of any 
discrepancies between EPA requirements and either (a) what a State 
requires from facilities

[[Page 54133]]

or (b) what a State has reported or intends to report. A State or the 
EPA could initiate a review by informing the other party that such a 
review is necessary. Any revised submissions by a State on its HAP 
collection program would need to meet the same March 31 deadline as for 
initial applications. A review of a State HAP reporting program could 
result in a revocation of approval to report.
    The EPA proposes that HAP reporting approval for a State would 
continue to apply for subsequent inventory years unless the EPA revokes 
the reporting approval and transfers responsibility back to owners/
operators. As with reporting approval, this revocation would be made 
via letter from the EPA to the state. The letter would be posted on the 
same website previously described to document which entities have 
reporting responsibility for which inventory years.
    In addition, the EPA proposes an approach for how a State, having 
previously been approved to report on behalf of owners/operators, could 
elect to revert HAP data reporting back to owners/operators. To 
initiate such a transfer, the EPA proposes that a State would need to 
notify the EPA in writing no later than November 1st of the year before 
the inventory year. For example, if the State intended for reporting to 
revert to owners/operators for the 2027 inventory year, the State would 
be required to notify the EPA by November 1, 2026. This timing would 
allow the EPA sufficient time to update CAERS to incorporate the 
additional owners/operators and their facilities. While the EPA will 
make every effort to review requests to revert responsibility to 
owners/operators in time for the desired inventory reporting year, 
there is no guarantee that the EPA will complete the review in time to 
meet the State's wishes. If approved by EPA, a request to revert 
responsibility to owners/operators would result in a revocation letter 
as described above.
8. Expansion of Point Source Definition To Include HAP
    The current AERR defines point sources for reporting to the EPA by 
States based on Table 1 to Appendix A of this subpart using PTE 
reporting thresholds for CAPs. To implement collection of HAP 
emissions, the EPA would need to determine criteria to specify which 
facilities would need to be reported by States and owners/operators as 
point sources for HAP. For the reasons discussed in this section, the 
EPA is proposing at 40 CFR 51.50 to expand the AERR-specific definition 
of point sources to ensure the appropriate facilities would be included 
for HAP reporting purposes.
    EPA first evaluated using the current AERR's CAP PTE reporting 
thresholds to define point sources. The EPA is not proposing this 
approach because there is no reasonable expectation that using these 
reporting thresholds to define point sources for HAP reporting would 
capture all sources with significant HAP emissions from a public health 
perspective. Such an approach could result in an incomplete reporting 
approach that would limit EPA's ability to obtain all needed HAP data. 
For example, hexavalent chromium is a component of PM2.5, so 
using the current AERR PTE threshold for PM2.5 would result 
in a 100 tons per year (tpy) PTE threshold for chromium. However, 
hexavalent chromium has been shown to cause significant public health 
risks at levels less than 100 pounds.\18\ Given this example and others 
like it, using the current AERR emissions reporting thresholds would be 
insufficient to fulfill the goals of this proposed action. By contrast, 
the EPA expects that two remaining approaches would provide EPA 
emissions data to support our public health mission: (1) collecting 
data from all facilities emitting any level of HAP or (2) setting 
specific HAP facility-wide emissions levels above which owners/
operators would need to report.
---------------------------------------------------------------------------

    \18\ See Chromium Electroplating NESHAP rule: https://www.epa.gov/stationary-sources-air-pollution/chromium-electroplating-national-emission-standards-hazardous-air proposal 
results (FR 65068, October 21, 2010), which found a maximum 
individual risk of 70-in-1 million from 33 lbs of hexavalent 
chromium emissions.
---------------------------------------------------------------------------

    To evaluate the approach of collecting data from all facilities 
emitting any level of HAP, the EPA considered the practical 
implications of collecting HAP data from all sources, specifically 
looking at the number of facilities that would be affected from certain 
common activities based on the 2017 Economic Census.\19\ Some examples 
of emissions sectors with many facilities that emit some level of HAP 
include restaurants (583,400), gas stations (112,600), and automotive 
repair and maintenance (162,000). Under the current AERR, EPA requires 
reporting of about 12,400 facilities as point sources. Further, States 
voluntarily submitted about 49,500 point sources for the 2017 NEI and 
about 59,800 for the 2020 NEI. If EPA now proposed to collect emissions 
from all facilities emitting any HAP, such a vast expansion could 
overwhelm both the States' and the EPA's abilities to manage the 
efforts effectively.
---------------------------------------------------------------------------

    \19\ U.S. Census Bureau, 2017 SUSB Annual Data Tables by 
Establishment Industry, https://www.census.gov/data/tables/2017/econ/susb/2017-susb-annual.html, May 2021, Excel file 
``us_state_naics_detailedsizes_2017.xlsx''.
---------------------------------------------------------------------------

    Further, an expansion to all facilities emitting any level of any 
HAP may cause undue burden on facilities that each emit a very small 
amount of HAP. At this time, the EPA estimates emissions from such 
sources as nonpoint sources on a county-wide basis. For example, for 
gas stations, the EPA estimates nonpoint emissions using the MOVES 
model for Stage II refueling from storage tanks to vehicles and data 
consistent with MOVES for Stage I refueling from tankers to storage 
tanks.\20\ For commercial cooking occurring at restaurants, EPA 
purchases data about the number of restaurants in each county and uses 
other data about food usage along with emission factors to estimate 
emissions.
---------------------------------------------------------------------------

    \20\ U.S. EPA, 2020 National Emissions Inventory, Technical 
Support Document, March 2023, EPA Document number EPA-454/R-23-001, 
https://www.epa.gov/air-emissions-inventories/2020-national-emissions-inventory-nei-technical-support-document-tsd.
---------------------------------------------------------------------------

    Based on these examples, the EPA does not now intend to require all 
emitters of HAP to report emissions at any level. In addition to the 
burden on the many small establishments, EPA and State resources would 
be diverted away from focusing on the more critical emitters due to the 
sheer volume of owners/operators that could be required to report 
without a more tailored approach. Such a tailored approach is 
consistent with CAA section 112, which provides the EPA with 
flexibility in setting requirements for area sources, which emit HAP at 
less than major source levels. So, it is appropriate for the EPA to 
consider how best to gather data about HAP emissions at those levels.
    The EPA is proposing to set new reporting thresholds for HAP, above 
which owners/operators of facilities would need to report emissions. 
The EPA is considering the following factors in defining reporting 
thresholds: (1) existing thresholds such as the major source definition 
and reporting thresholds for the TRI; (2) which pollutants should be 
reported; (3) the degree of human health impact on communities caused 
by differences in toxicity of pollutants; and (4) a desire to focus 
data collection efforts on facilities with the potential to cause 
significant and ongoing impacts while avoiding less beneficial 
reporting by many small, lower impact facilities. Each of these 
considerations is described in the paragraphs below.
    Factor 1: For existing thresholds, CAA section 112 provides the 
definition of HAP major sources as the potential to

[[Page 54134]]

emit 10 tpy of any HAP or 25 tpy of any combination of HAP. The EPA 
must also address emissions of all HAP in its actions to regulate major 
sources. In addition, major sources are already well versed in the 
regulatory requirements under which they operate, and many of these 
sources also must report to the TRI program. For these reasons, a 
logical and reasonable approach for a minimum requirement would be that 
major sources would report all HAP to be consistent with the regulatory 
programs and requirements that the EPA seeks to meet.
    In addition to the emissions thresholds associated with the major 
source definition, the EPA is considering reporting thresholds set with 
the requirements for TRI. That program has reporting criteria based on 
the number of full-time employees; primary NAICS; chemicals a facility 
manufactures, processes, or otherwise uses; and activity levels. As a 
result, the TRI reporting thresholds are not based on facility air 
emissions; therefore, those thresholds have less relevance for this 
proposed action. For many reasons including emissions controls that 
reduce emissions, the amount of a HAP emitted to air is very different 
from the amount manufactured, processed, or otherwise used by a 
facility. For this reason, the TRI program's reporting thresholds are 
not being proposed as the primary approach for setting reporting 
thresholds for non-major sources under this subpart. A benefit to this 
approach is that any data that would be collected under this action 
would likely include sources not reporting to the TRI program and would 
fill gaps in the agency's data collection.
    Factor 2: The EPA also is considering which pollutants should be 
reported. As previously described, a policy under which major sources 
to report all HAP is most supportive of EPA's needs for HAP data. For 
sources other than major sources (also known as ``area sources'' under 
CAA section 112 and hereafter referred to as ``non-major'' sources), 
the EPA is considering both whether to require air toxics \21\ other 
than listed HAP and which HAP (or other) pollutants should be reported.
---------------------------------------------------------------------------

    \21\ Although it has become common practice to use the terms 
``air toxics'' and ``hazardous air pollutant'' interchangeably, air 
toxics is a broad term that includes all compounds of some 
recognized toxicity and is not limited to those HAP identified by 
the CAA and EPA HAP listings. For example, a more extensive listing 
of air toxics is included by TRI-listed chemicals, available via the 
TRI website at https://www.epa.gov/toxics-release-inventory-tri-program/tri-listed-chemicals.
---------------------------------------------------------------------------

    Regarding air toxics other than listed HAP, the EPA is considering 
two possible approaches: (1) requiring air toxics that are already 
required by States and (2) requiring air toxics that are required by 
the TRI program. Either of these approaches would provide additional 
detailed data for the EPA to analyze air toxic emissions in the context 
of listing new HAP. Both approaches also would constrain reporting to 
pollutants that are already being collected, which would have a lower 
burden than other conceivable approaches. In the case of an approach 
based on TRI air toxics (called chemicals by the TRI program), 
additional burden beyond a State-based approach would be incurred by 
owners/operators because those owners/operators are currently reporting 
facility total data to TRI and would have to report more detailed data 
to the NEI. On the other hand, if an owner/operator is already 
reporting to TRI, then the incremental effort for such a facility is 
lower when compared to a facility not reporting air toxics data at all, 
because the aggregated information is currently collected and reported.
    For the first approach (i.e., requiring States to report additional 
air toxics that they already collect), the EPA observes that such data 
are largely being submitted voluntarily under the current AERR. 
Furthermore, since different States collect different air toxics, it 
would be challenging for the EPA and owners/operators to keep track of 
State requirements to ensure compliance with a Federal rule that relied 
on State rules for defining what pollutants were required by that 
State. In addition, EPA's need for other (non-HAP) air toxics data is 
not currently as significant as the need for HAP data because the use 
of the additional air toxics is largely limited to consideration of 
listing new HAP. Also, this more limited need for the data is already 
met to some degree by the facility total data from TRI and from 
voluntary reporting by some States. Based on these considerations, the 
EPA is not proposing to use State requirements to set the required 
pollutants for reporting by owners/operators (i.e., beyond the HAP 
proposed for collection).
    EPA is also considering using the required TRI chemicals to 
determine which pollutants should be reported under the AERR. As 
described above, this proposed action envisions that States could apply 
for approval to report HAP on behalf of the owners/operators of 
facilities who would otherwise report emissions data directly to EPA. 
If the EPA implemented a requirement that all chemicals required by TRI 
would also need to be reported to the NEI, States choosing to report 
HAP would need to revise their emissions reporting rules not only to 
collect HAP, but to also collect the additional air toxics as well. 
Given the more limited need for other air toxics data besides HAP at 
this time (i.e., primarily for considering listing as HAP), EPA's 
current assessment is that the additional burden on States that choose, 
on behalf of owners/operators, to report all air toxics reported to TRI 
is not warranted in these proposed revisions.
    Another aspect of this factor is that some pollutants may be added 
to or removed from the list of HAP over time. For major sources, any 
new HAP would be required to be reported and any exempted HAP would no 
longer be required if a policy requiring all HAP were to be finalized 
based on this proposed action. For non-major sources, however, a newly 
identified HAP would require an emissions reporting threshold to be set 
through future regulatory revisions.
    Factor 3: The EPA is also considering the degree of human health 
impact on communities as a factor in setting emissions reporting 
thresholds. The focus of such reporting thresholds is to ensure that 
non-major sources that have significant potential health impacts are 
included in the emissions reporting. A reasonable approach for all 
pollutants and facility types is to consider estimated risk based on 
the available NEI HAP emissions that have been voluntarily reported by 
States or included from the TRI program. To develop and assess risk-
based reporting thresholds, the EPA used the data available from the 
2017 AirToxScreen.\22\ EPA understands that there are limitations to be 
considered when looking at these results, including data gaps due to 
voluntary HAP reporting and TRI data available only for certain 
facilities. These limitations are described as part of the AirToxScreen 
limitations website \23\ as well as the technical documentation 
available with the latest AirToxScreen results.\24\ Given these 
limitations, the EPA has developed an approach that would use the 
available data in a way to lessen any impacts of incomplete data.
---------------------------------------------------------------------------

    \22\ The EPA 2017 AirToxScreen, https://www.epa.gov/AirToxScreen.
    \23\ U.S. EPA, AirToxScreen Limitations website, https://www.epa.gov/AirToxScreen/airtoxscreen-limitations.
    \24\ U.S. EPA, AirToxScreen Technical Support Documentation, 
https://www.epa.gov/AirToxScreen/airtoxscreen-technical-support-document.
---------------------------------------------------------------------------

    The approach taken to develop the proposed reporting thresholds is 
fully documented in a separate Technical Support Document (TSD) \25\ 
and is

[[Page 54135]]

briefly summarized here. First, the EPA modeled air quality pollutant 
concentrations around facilities and post-processed those results to 
use only concentrations no closer than 100 meters from each emission 
point within the facility. This 100-meter approach avoids overly high 
concentrations that can occur within the ``fence lines'' of facilities. 
``Fence line'' is a phrase used to denote the outer perimeter boundary 
of the land on which a facility operates. Typically, members of the 
public would not be exposed to concentrations that exist within the 
fence line. Both major and non-major facilities can vary in land 
coverage, and this approach is an approximation that assumes that 100-
meters is an adequate distance between an emission point and the 
associated fence line for purpose of this analysis. In doing so, EPA 
has avoided including high concentrations of HAP that can occur within 
the fence line of major and non-major sources and instead focuses on 
concentrations to which the public would more typically be exposed. In 
this analysis, about 95 percent of the distances between emission 
release points and the associated location of maximum risk from the 
release point was between 100 and 2500 meters, and the remainder were 
even farther away. The EPA used the resulting modeled concentrations to 
compute cancer risk estimates using pollutant-specific unit risk 
estimates (UREs) \26\ and other health impacts (e.g., respiratory, 
neurological) with the reference concentration (RfC) for the most 
impacted organ system. Generally, the EPA used the same UREs and RfCs 
to calculate cancer risk and non-cancer hazard index (HI) as are 
currently used in other EPA regulatory actions, and the TSD provides 
exceptions to that general approach.
---------------------------------------------------------------------------

    \25\ U.S. EPA, Technical Support Document: Revisions to the Air 
Emissions Reporting Requirements (Proposal), April 2023, available 
in the docket for this proposal.
    \26\ For assessments of HAP, the EPA generally uses UREs from 
EPA's Integrated Risk Information System (IRIS). For carcinogenic 
pollutants without IRIS values, we look to other reputable sources 
of cancer dose-response values, often using California EPA (CalEPA) 
UREs, where available. In cases where new, scientifically credible 
dose-response values have been developed in a manner consistent with 
EPA guidelines and have undergone a peer review process like that 
used by the EPA, we may use such dose-response values in place of, 
or in addition to, other values, if appropriate.
---------------------------------------------------------------------------

    Using the cancer risk and HI estimates, the EPA calculated the 
level of emissions (``adjusted emissions'') that would be needed to 
cause one in a million risk and/or a 0.5 HI for each release point and 
HAP at all facilities in the 2017 data. This calculation is possible 
because the cancer risk and HI results from the modeling performed can 
be scaled linearly based on emissions. To guard against including 
release points and pollutants that contribute very minor risk to the 
overall facility risk, the EPA excluded any release point/pollutant 
combination that contributed to less than 20 percent of the cancer risk 
and HI in the 2017 modeled estimates for the associated facility.\27\ 
The emissions scaling approach allows for the large variety of stacks 
and fugitive releases with varied parameters to contribute to the 
information with which the EPA could develop emissions reporting 
thresholds. Dropping the release point/pollutant combinations that 
contributed less than 20 percent of the cancer risk and HI also removes 
the smaller sources from the data, which avoids including in the 
analysis those types of emissions within facilities that may be less 
consequential to overall cancer risk and HI at those facilities. Rather 
than rely on a single facility or selected facilities, the approach 
provides for a distribution of possible emissions reporting thresholds 
so that the EPA can ensure that emissions reporting thresholds are both 
robustly based on available data and not overly low causing undue 
burden.
---------------------------------------------------------------------------

    \27\ More information on EPA's approach to set risk-based 
emissions reporting thresholds is available in Section 3 of the TSD 
for this proposal. Section 3.1 of the TSD further addresses issue of 
dropping some data values as part of establishing proposed 
thresholds.
---------------------------------------------------------------------------

    The EPA evaluated several approaches for using the distributions of 
adjusted emissions to set an emissions reporting threshold. Ultimately, 
the EPA settled on the 10th percentile of the adjusted emissions. 
Before arriving at this conclusion, the EPA evaluated the distributions 
of adjusted emissions data by using histograms. Both the raw data and 
log-transformed data were evaluated. While a handful of the log-
transformed distributions approximated a normal distribution, most of 
the distributions had a significant high value bias or low value bias. 
Because most histograms did not appear normally distributed, the EPA 
has chosen not to use an approach that would rely on standard deviation 
from the median of adjusted emissions. The EPA also evaluated using the 
median values of the distributions of adjusted emissions to set an 
emissions reporting threshold, but these median values were often 
several orders of magnitude higher than emissions levels estimated to 
cause significant risks based on the 2017 Air Toxics Data Update.
    In reviewing the range of values from the distributions of adjusted 
emissions, the EPA determined that the 10th percentile of the adjusted 
emissions provided a reasonable reporting threshold for each pollutant. 
Percentiles below that level too often approached the minimum emissions 
levels causing risk in the 2017 Air Toxics Update, and percentiles 
above that level may not be rigorous enough to ensure that the EPA 
collects sufficient data to be protective of human health.
    The EPA is also considering how to collect data from non-major 
facilities that have the potential to cause significant and ongoing 
impacts without requiring many smaller, lower impact facilities to 
report. As illustrated by the previous example of gas stations, some 
emissions sectors tend to have many small individual sources that can 
be included in the NEI as county total emissions rather than be 
included as point sources. To tailor reporting for non-major sources to 
specific industries, the EPA analyzed the available 2017 NEI HAP 
emissions data to assess the contribution of emissions from each NAICS 
code to the total point source emissions for each pollutant. The EPA 
applied a threshold of 1 percent contribution by NAICS grouped to the 
first 4 digits of the NAICS code for each pollutant. The EPA set this 1 
percent threshold to be a conservative approach to identify NAICS-
pollutant combinations for consideration in any proposed policy 
approaches before further reviewing each NAICS for relevance in 
supporting objectives of this proposed action. By merging the 4-digit 
NAICS with the full list of NAICS codes, the EPA created a short-list 
of NAICS-pollutant combinations of interest.
    The EPA further excluded a NAICS-pollutant combination if: (1) the 
NAICS is not currently widely reported as point sources by States for 
other reasons and either (2) the NAICS is in an agricultural production 
sector or a retail sector more likely to contribute emissions from many 
small sources that would better be captured as nonpoint emissions, or 
(3) the NAICS is in a service sector (e.g., advertising) that is not 
expected to include significant pollutant emissions. Some NAICS were 
specifically included when they were used for activities that emit 
significant amounts of high-risk pollutants such as ethylene oxide or 
hexavalent chromium. With this approach, the EPA is attempting to 
strike an appropriate balance between the agency's need for information 
with the burden that reporting requirements impose on owners/operators 
and/or States. While the EPA utilized its technical discretion to 
exclude these NAICS-pollutant combinations at this time, the agency 
recognizes that it may be appropriate to revisit these exclusions in 
the future.

[[Page 54136]]

    To understand the impact of any potential reporting thresholds, the 
EPA has estimated the number of additional non-major sources from the 
2017 NEI that would have been included for mandatory HAP reporting had 
the EPA compiled the 2017 NEI using HAP reporting thresholds based on 
the 10th percentile thresholds and NAICS selection approach described 
above in addition to special threshold adjustments proposed in section 
IV.A.9. This analysis showed that about 115,000 non-major sources could 
be added to reporting requirements that currently affect about 13,400 
major sources. In making these estimates, the EPA has made numerous 
assumptions that would tend to overestimate the number of facilities 
that would need to report, to provide conservative estimates for 
purposes of burden estimates. The EPA estimates the actual number of 
facilities to be lower. More information on this analysis is available 
in the TSD for this proposal.
    Additionally, while owners/operators and States would be newly 
required to report for more facilities, States voluntarily reported HAP 
for the 2017 NEI (and therefore collected HAP from owners/operators 
largely via State requirements) for about 59,000 facilities, which is 
about 46% of the approximately 129,500 facilities EPA estimates would 
report under this proposal rule. As a result, the incremental burden 
increase of EPA's HAP collection approach would be lower than if all 
facilities needed to be newly reported under the proposed AERR 
revisions. In the cases in which a State does not choose to report HAP 
on behalf of owners/operators under this proposal, the HAP reporting 
requirements for such facilities could change in two possible ways. 
First, the reporting requirements could shift from being a State 
requirement to an EPA requirement for owners/operators of facilities 
within States that use CAERS in some way or that eliminate their State 
reporting rule. Second, the reporting requirements could become 
duplicative for owners/operators within States that choose to not use 
CAERS in any way and retain their State reporting rule. For those 
pollutants owners/operators are already reporting to the State, there 
is little increase in burden. For those additional pollutants (if any) 
that would be required under this proposed rule, owners/operators will 
have an incremental burden for those additional pollutants but would 
not need to learn about emissions reports in general. Further, the 
expected increase in facilities and burden needs to be considered in 
light of the need by EPA, States, and the public for data that allows 
for better understanding and reducing public health risks to 
communities. While the current AERR voluntary HAP collection program 
gathers a lot of data, the voluntary data does not necessarily have 
those pollutants that EPA's analysis shows are most important at those 
facilities and does not include all the facilities that the analysis 
shows should be collected to inform risk assessments and other EPA 
analyses.
    Based on these considerations, this action proposes to expand the 
definition of point sources at 40 CFR 51.50 to mean a stationary or 
portable facility that (1) is a major source under 40 CFR part 70 for 
any pollutant, or (2) has PTE or annual actual emissions of pollutants 
greater than or equal to the reporting thresholds in Table 1A to 
Appendix A of this subpart, or (3) has a primary NAICS code listed in 
Table 1C to Appendix A of this subpart and annual actual emissions of 
pollutants greater than or equal to the HAP reporting thresholds 
(presented in Table 1B to Appendix A of this subpart). Additionally, 
the EPA is proposing as part of this definition that, in assessing 
whether emissions levels exceed reporting thresholds, all provisions of 
this subpart related to emissions estimation approaches would apply, 
including Sec. Sec.  51.5 and 51.10 of this subpart.
    To further clarify the definition of point sources based in part on 
primary NAICS (situation #3 in the paragraph above), the EPA 
additionally proposes a definition of primary NAICS. The EPA proposes 
that primary NAICS means the NAICS code that most accurately describes 
the facility or supplier's primary product/activity/service and that 
the ``primary product/activity/service'' is the principal source of 
revenue for the facility or supplier. This definition is being proposed 
so that the AERR can be consistent with the non-regulatory definition 
of primary NAICS used by the U.S. Census bureau. This proposed 
definition would serve for purposes of this subpart for both 
identifying point sources and reporting primary NAICS.
    To set the point source definition, the EPA is proposing to expand 
the current Table 1 to Appendix A of Subpart A of Part 51 into four 
tables (Tables 1A through 1D of Subpart A of Part 51). Table 1A 
provides the proposed point source reporting thresholds for CAPs, which 
the EPA proposes would remain unchanged. Table 1B provides the proposed 
HAP initial reporting thresholds for non-major sources. Table 1C 
provides a proposed list of primary NAICS for non-major sources, and 
Table 1D provides a proposed list of individual compounds to be 
reported for groups of chemicals with a single reporting threshold from 
Table 1B. More information on Table 1D is provided in section IV.I.14 
of this preamble.
9. Special Cases of Emissions Thresholds for Non-Major Sources
    The risk-based analysis above was not completed for five 
situations, which are covered in this section: (1) mercury compounds, 
(2) pollutants included in the 2017 NEI but without URE or RfC, (3) 
revisions or publication of new URE or RfC, (4) a special case for 
dioxins/furans, and (5) the treatment of Pb as both a CAP and HAP.
    The risk-based approach was insufficient for mercury compounds 
because they have multi-pathway (air, water, soil) effects that were 
not captured by the analysis described above.\28\ Without further 
evaluation to consider a more inclusive approach, the above approach 
may set too high a reporting threshold for mercury. It is important to 
ensure complete mercury reporting from sources because, in addition to 
using mercury data for risk analysis, the EPA reports trends in total 
national mercury emissions based on international agreements such as 
the Minamata Convention on Mercury and the Convention on Long-Range 
Transboundary Air Pollution. Evaluation of the available 2017 NEI data 
shows that the reporting threshold resulting from the mercury HI in the 
approach from section IV.A.8 of this preamble (0.15-ton) would require 
reporting for only 22 out of about 16,000 sources of mercury currently 
compiled in the 2017 NEI. Based on the 2017 emissions data to capture 
95 percent of the mass of mercury nationally, a reporting threshold of 
0.0026 tons (5.2 lbs) would be needed. To capture 99 percent of those 
known values, a reporting threshold of 0.0003 tons (0.6 lbs) would be 
needed.
---------------------------------------------------------------------------

    \28\ Like mercury, other HAP can be persistent/bioaccumulative 
(PB-HAP) pollutants that have multipathway effects. Other examples 
include arsenic, cadmium, dioxins/furans, lead, and PAHs. For this 
proposal, EPA considered only the inhalation pathway for all PB-HAP 
pollutants. The inhalation-based thresholds for the PB-HAP, except 
mercury, were deemed appropriate for this proposal, but EPA could 
consider multipathway effects in other future rulemaking efforts 
that could result in different emissions reporting thresholds.
---------------------------------------------------------------------------

    The EPA also is considering that mercury emissions in its divalent 
form is the portion of mercury emissions of most concern. 
Unfortunately, sources often have little information about the form of 
the mercury emitted. Measuring

[[Page 54137]]

divalent mercury is much more difficult than simply measuring the total 
mercury emitted.
    Based on these considerations, the EPA is proposing a mercury 
reporting threshold of 0.0026 tons (5.2 lbs), which is based on the 
value that captures 95 percent of currently best available data about 
mercury from point sources. Irrespective of the form(s) of mercury 
reported, the reporting threshold is proposed to be based on total 
mercury. The proposed reporting threshold is about two orders of 
magnitude lower than the incomplete HI-based approach described above, 
which the EPA proposes is reasonable given what is known about multi-
pathway exposures for mercury. The EPA additionally proposes that 
mercury would be reported in its more specific forms when such data are 
available, but that total mercury would be reported when more specific 
forms are not available.
    The EPA considered how to set a default emissions reporting 
threshold for all remaining pollutants without an URE or RfC. Without 
risk data to use to inform such an approach, EPA has proposed to use 
the major source threshold of 10 tons/year for a single pollutant. For 
the third special case, the EPA is considering that it may be useful to 
have a mechanism by which the Agency would revise reporting thresholds 
for pollutants in the case that a significant revision to an existing 
URE or RfC becomes available following new scientific findings that 
could significantly impact EPA's understanding of risk posed by such a 
pollutant. One example of this situation is provided by ethylene oxide 
(EtO), when the EPA determined EtO was a much more potent carcinogen 
than previously realized.\29\ Rather than being able to rely on an 
existing requirement to collect data more quickly as is being proposed 
here, the EPA needed to collect data ad-hoc from 2019 through to 2022 
to obtain additional emissions data about these facilities. The data 
collection process took additional time, delaying a response that could 
have more quickly addressed public health concerns. This delay would 
have been avoided if emissions data reporting requirements had, at that 
time, included a provision such as the one the EPA is now considering.
---------------------------------------------------------------------------

    \29\ U.S. EPA, Evaluation of the Inhalation Carcinogenicity of 
Ethylene Oxide (Final Report), EPA/635/R-16/350F, 2016.
---------------------------------------------------------------------------

    The EPA has a tiered, prioritized list of appropriate chronic 
health benchmark values and, in general, the list prioritization places 
greater weight on the EPA-derived health benchmarks than those from 
other agencies.\30\ The EPA has a prioritization process aimed at 
incorporating the best available science with respect to dose-response 
information for air toxics. This information is obtained from various 
sources and prioritized according to (1) conceptual consistency with 
EPA risk assessment guidelines and (2) level of peer review received. 
Where the EPA lacks dose-response information with higher priority 
(e.g., IRIS), the Agency uses other information sources, such as from 
the Agency for Toxic Substances and Disease Registry (ATSDR) and the 
California EPA. To ensure the EPA could collect emissions data for HAP 
that receive updated health benchmarks that meet the EPA criteria and 
would receive prioritization, it would be necessary to adjust the 
health-based emissions reporting thresholds included in this proposal.
---------------------------------------------------------------------------

    \30\ The health benchmark review process is described at https://www.epa.gov/iris/basic-information-about-integrated-risk-information-system#process.
---------------------------------------------------------------------------

    The EPA occasionally identifies new health benchmarks for 
pollutants that do not have them or revises the available benchmarks to 
reflect a new understanding of a HAP's increased or decreased toxicity. 
When the available toxicity information about pollutants changes in the 
future, the EPA expects that it will propose updated emissions 
reporting thresholds, take comment, and potentially issue final 
revisions to the HAP emissions reporting thresholds of this subpart. At 
this time, EPA plans to conduct such revisions in the future via very 
targeted rulemaking to amend just those HAP emissions reporting 
thresholds where the toxicity information has changed.
    To streamline future actions associated with any revised health 
benchmarks, the EPA proposes that it may use the following formulas to 
develop updates for the point source HAP reporting thresholds of this 
subpart. For changes to UREs, the updated reporting threshold would be 
calculated using the formula: Updated reporting threshold = (reporting 
threshold in AERR x URE in 2022)/updated URE, where the ``reporting 
threshold in AERR'' refers to the reporting thresholds provided in the 
proposed Table 1B to Appendix A of this subpart. For changes to RfCs, 
the updated reporting threshold would be calculated using the formula: 
Updated reporting threshold = (reporting threshold in AERR x revised 
RfC)/RfC in 2022.
    Further, the EPA proposes that only those HAP reporting thresholds 
that the EPA publishes in the Federal Register (after notice and 
comment) 6 months before the end of an inventory year would apply for 
reporting emissions for that inventory year. For example, any reporting 
threshold published before July 1, 2027, would be relevant for 
emissions reporting of 2027 emissions, with those reports being due in 
2028. This timing may not leave sufficient time for States to revise 
their HAP reporting regulations if they are reporting on behalf of 
owners/operators. Thus, the EPA recommends that States should consider 
the possibility of drafting their HAP reporting requirements such that 
they would refer to Table 1B to Appendix A of this subpart rather than 
list the same thresholds in their own rules. The EPA additionally 
proposes to publish any updates to emissions reporting thresholds on 
its Air Emissions Inventories website to help States and owners/
operators to be able to find the new reporting thresholds more easily.
    Some pollutant reporting thresholds included for non-major sources 
in the proposed Table 1B to Appendix A of this subpart are listed as 10 
tpy, which is the major source threshold. If a point source had 
emissions of 10 tons, then it would presumably be subject to these 
proposed reporting requirements based on its status as a HAP major 
source, which would eliminate the need for including such reporting 
thresholds in the table. However, to support the possibility that an 
emission reporting threshold could be updated based on changes to a 
pollutant's URE or RfC, the 10-ton reporting threshold would be 
retained in the proposed Table 1B to Appendix A of this subpart to 
provide the ``reporting threshold in AERR'' value needed for the 
updated reporting threshold calculations proposed above. Additionally, 
including those pollutants in Tables 1B and 1D allows for a more 
comprehensive list of pollutants to inform owners/operators and States 
of EPA's expectations and so that the pollutant group relationships 
listed in Table 1D can be provided.
    The fourth special case is dioxins/furans. These pollutants were 
not included in the risk-based approach described above since they were 
not included in the 2017 NEI and were not a part of the risk modeling 
work on which the approach relied. Given the extremely high toxicity of 
some dioxins/furan pollutants (called congeners), the EPA is 
considering the approach taken by the TRI program. In addition, while 
dioxins/furans are not listed as a group on the published list of HAP, 
these HAP are often treated as a group for various purposes. For 
example, the TRI program

[[Page 54138]]

sets a reporting threshold for these compounds in the aggregate of 0.1 
gram manufactured, processed, or otherwise used. For TRI reporting, 
when owners/operators report dioxins/furans, they must submit the mass 
of each of the congeners of dioxins/furans.
    The EPA proposes the non-major reporting threshold for reporting 
dioxins/furans would be based on the TRI reporting threshold of 1.1 E-
07 tons (~0.1 gram) and would apply to the sum of dioxins/furans mass. 
To meet this requirement, owners/operators would need to sum the mass 
of the individual congeners. By proposing this threshold for the AERR, 
the EPA is aligning the thresholds as best as possible to reduce 
complexity and burden. The EPA's proposed approach for the AERR is a 
less stringent threshold than the TRI threshold because facilities that 
manufacture, process, or otherwise use dioxins/furans would likely not 
emit all of that material to the air. As such, the EPA is not adding 
any burden on facilities to recognize that they may need to report to 
the AERR, but rather to estimate their dioxin/furan emissions at the 
additional level of detail proposed in the AERR as compared to the 
facility total emissions reported to TRI.
    Finally, with respect to the Pb reporting threshold, the EPA is 
considering that Pb has a role for both CAP reporting and HAP 
reporting, since it falls under both NAAQS and air toxics provisions of 
the CAA. The EPA is not proposing to change CAP reporting thresholds 
(including Pb) in Table 1A to Appendix A of this subpart and is not 
proposing to change the current AERR requirement to report all CAP 
emissions if any CAP is above the PTE reporting thresholds (or Pb 
actual emissions threshold). The EPA approach for risk-based reporting 
thresholds described in section IV.A.8 results in a 0.074 tpy Pb 
reporting threshold. The EPA is considering that if it were to modify 
the CAP reporting threshold for Pb to be 0.074 tpy, this would have the 
effect of requiring reporting for all CAPs at facilities with Pb 
exceeding the 0.074 tpy threshold. The EPA does not intend to require 
CAP emissions (other than Pb) as point source for such small emissions 
levels. Based on these considerations, the EPA is proposing to retain 
the 0.5 tpy actual emissions reporting threshold for CAP reporting and 
additionally propose a Pb reporting threshold of 0.074 tpy actual 
emissions for purposes of HAP reporting.
    Under the proposed approach, all States would continue to report Pb 
for point sources as required based on the CAP reporting thresholds. 
States that optionally report HAP on behalf of owners/operators would 
also report Pb for sources based on the HAP reporting threshold, and 
any other HAP from those facilities that would be required by this 
proposed action, and any other pollutants, including CAPs, that the 
State chooses to report. In States that do not report HAP on behalf of 
facilities, owners/operators would themselves be responsible for 
reporting Pb directly to the EPA for any facility that emits over the 
HAP reporting threshold (0.074 tpy) and that does not exceed the CAP 
reporting thresholds (for any CAP) and thus would not be required to be 
reported by a State.
    Under the current AERR, some States voluntarily report Pb emissions 
for sources below the required reporting thresholds for CAPs. Thus, 
under the proposed approach, it is possible that the EPA could receive 
Pb data from both a State and an owner/operator for the same facility. 
In this case, the EPA would need to select one of these data values to 
include in the NEI. If an owner/operator is required to report (and 
does report) Pb emissions data for a facility (i.e., the State is not 
approved to report on their behalf), but the State also voluntarily 
submits that data for the same facility, then the EPA will use the data 
from the owner/operator. The EPA would plan to note any difference 
between the emissions submitted by the State and the owner/operator in 
quality review materials provided to both parties.
10. Pollutants To Be Required or Optional for Point Sources
    The EPA is considering which pollutants would be reported by 
owners/operators of facilities once a facility has been determined to 
be a point source. This action does not propose changes to which CAPs 
would be reported. With the proposed revision to require HAP, the EPA 
is considering how to handle cases in which a facility is required to 
report HAP but does not exceed the reporting threshold for CAPs. The 
term ``incidental CAPs'' will be used hereafter to refer to CAP 
emissions that would be reported only because a facility is a point 
source due to its HAP emissions. This situation is exemplified by a 
facility that emits one ton of nickel per year (exceeding the proposed 
Ni reporting threshold of 0.0021 tpy) but does not exceed the 100 tpy 
potential-to-emit reporting threshold for PM2.5. An ideal 
policy should include a mechanism to prevent the discrepancy that would 
result when the facility reports the nickel emissions of one ton and 
zero PM2.5 emissions, since nickel is a part of 
PM2.5.
    To address this issue, the EPA is proposing to require reporting of 
incidental CAPs by owners/operators that report HAP for point sources, 
and by States when a State has been approved to report HAP on behalf of 
owners/operators. To support this requirement, the EPA is additionally 
proposing the definition of incidental CAPs to mean ``a criteria 
pollutant or precursor emitted from a facility that meets the point 
source reporting definition due to emissions of HAP but has emissions 
of criteria pollutants and precursors below reporting thresholds for 
those pollutants.'' To inform this proposed approach, the EPA is 
considering whether a voluntary approach or a requirement would work 
best and the nature of any requirement.
    Under a voluntary approach, owners/operators or States would not be 
required to report incidental CAPs, but such emissions could be 
reported voluntarily. This would impose a lower burden but may create 
inconsistencies in the NEI data at the facility level when CAP data are 
not voluntarily reported (as described by the example provided above 
about a facility reporting nickel without reporting PM2.5). 
To address any such inconsistencies, the EPA could augment the NEI by 
summing any HAP reported without associated CAPs. For example, if a 
facility were to report 1 ton of nickel, 0.2 tons of cadmium, and 0.3 
tons of antimony as their only PM HAP, then the EPA could sum these 
values to include 1.5 tons of PM2.5 in the NEI. While 
avoiding inconsistency, this approach would create partial data for 
PM2.5 that would appear to be complete, and thus could cause 
confusion that would be better to avoid by estimating or collecting 
total PM2.5.
    The EPA also is considering the possibility of using the required 
throughput (activity) data reported by owners/operators for the HAP to 
estimate the CAP emissions on behalf of owners/operators. This approach 
slightly reduces burden as compared to the proposed approach of 
requiring incidental CAP, though it complicates the NEI process and 
adds annual emissions data to the NEI after owners/operators have 
already submitted. In the past, the EPA has found that if owners/
operators or States do not submit complete emissions, they can be 
surprised by EPA's additions to their data prior to NEI publication. 
Further, there is no guarantee that all sources of the incidental CAP 
at a facility also have emissions of HAP, making any estimate by the 
EPA based on throughput data used to estimate HAP potentially 
incomplete. In EPA's experience, these disadvantages are better 
avoided.

[[Page 54139]]

    A requirement to report incidental CAPs has the advantages of 
collecting additional CAP emissions data for a more detailed NEI and 
boosting consistency between emissions of HAP and their associated CAPs 
(like VOC and PM2.5). Such a requirement would also have the 
disadvantage of additional burden on owners/operators to estimate and 
report more pollutants.
    In considering a requirement to report incidental CAPs, the EPA is 
considering two possibilities for implementation: (1) States could be 
required to report CAP emissions of such sources rather than owners/
operators, consistent with the overall CAP reporting approach taken in 
the AERR or (2) owners/operators could be required to report CAPs 
directly to the EPA consistent with the HAP reporting requirement. To 
implement the first approach, all States would need to modify their 
State regulations to update the definition of which sources would 
report CAPs to include HAP reporting thresholds. Such a modification 
would be necessary under the first approach, regardless of whether the 
State intends to be responsible for reporting HAP emissions on behalf 
of owners/operators. This poses a significant disadvantage.
    The EPA is proposing the second approach listed above for owners/
operators to report incidental CAPs. This approach does not require 
States to modify their CAP reporting regulations and still allows 
States to report incidental CAPs if they report HAP emissions. Under 
the proposed approach, the State HAP submission application and 
approval process described in section IV.A.6 of this preamble would, 
therefore, also include the reporting by States of incidental CAPs 
associated with such facilities. The proposed approach also works well 
with the requirement for owners/operators to report emissions using 
CAERS, because CAERS assists owners/operators with emissions factors 
for both HAP and CAPs associated with their emissions processes and 
provides other advantages to streamline reporting. Additionally, the 
EPA plans that future versions of CAERS would have the direct access to 
the source tests reported to CEDRI to support use of source test data 
for estimation of incidental CAP. The EPA expects the source test data 
to be useful for this, because of the frequent approach taken by NESHAP 
rules to collect a surrogate pollutant report, such as filterable 
PM2.5, to ensure compliance with HAP emissions limits. Thus, 
the incremental burden for a facility reporting to the EPA directly via 
CAERS to report incidental CAPs would be lower than if CAERS were not 
required. Since some such facilities may not already be regulated for 
CAPs by States, some may be less likely to have source testing or other 
emissions factor data. In these cases, owners/operators could simply 
use the default emissions factors provided by the EPA in CAERS when 
available.
    Based on these considerations, the EPA proposes that owners/
operators would be required to report incidental CAPs associated with 
HAP being reported when they are required to report HAP but would not 
otherwise be required to report CAP (i.e., they are not a major source 
for CAP). This requirement would impact reporting emissions for HAP 
major sources and for non-major sources when required to report HAP.
    If applying to the EPA to report HAP on behalf of owners/operators, 
a State would need to consider the incidental CAP requirement when 
designing any updated emissions collection regulations. The proposed 
Table 1B to Appendix A of this subpart includes which criteria 
pollutants are associated with each HAP and would determine the CAPs 
expected to comply with this propose incidental CAP reporting 
requirement. This approach has the advantages previously noted and, in 
addition, it solves the same collection and consistency challenge for 
States by providing a framework for any States that choose to report 
HAP on behalf of owners/operators.
    In addition to incidental CAPs, the EPA is considering which HAP 
would be reported by owners/operators of facilities that meet the point 
source definition. As described above, this action proposes that 
owners/operators of HAP and CAP major sources report all HAP. This 
proposed requirement would be consistent with EPA's obligations under 
the Act to regulate all pollutants from such HAP major sources and 
includes CAP major sources to have available to the agency a complete 
suite of pollutants from all large emitters.
    For non-major sources, the EPA proposes that owners/operators would 
be required to report only those HAP that are greater than EPA's HAP 
reporting thresholds, initial values for which are presented in the 
proposed Table 1B to Appendix A of this subpart. To identify this 
proposed approach for non-major sources, the EPA compared this proposed 
approach to an alternative by which owners/operators of non-major 
sources would report all HAP when any one HAP has emissions greater 
than or equal to the proposed reporting thresholds. To choose an 
approach, the EPA is weighing the additional burden associated with 
reporting all HAP relative to the importance of additional data that 
would be collected if all HAP were required.
    To understand the effects of this proposed action, the EPA 
evaluated the relative impact of the HAP pollutant requirements. The 
incidental CAP impact is expected to be small because it would add just 
one or two pollutants per facility and the requirement could be met 
using emissions factors. Thus, the incremental CAP impact was not 
separately analyzed from the total HAP impact. The EPA used the 2017 
NEI data to estimate the number of additional combinations of 
facilities and HAP pollutants as a surrogate to estimate incremental 
burden from each policy choice relative to the option of reporting all 
HAP for HAP major sources. Table 1 below provides these results by 
including a ``burden'' factor calculated using the estimated number of 
facility-pollutant combinations associated with a policy option divided 
by the estimated number of facility-pollutant combinations associated 
with all pollutants from the identified HAP major facilities.
    These relative burden estimates are imperfect because they rely on 
the 2017 NEI that is known to be incomplete (since HAP reporting is 
currently voluntary), but they still represent the best data available 
to the EPA at the time the analysis was performed. To compare the 
burden between the proposed non-major approach and the alternative non-
major approach, the EPA counted the number of records in the 2017 NEI 
with HAP emissions. In the proposed case, the EPA included only those 
records associated with the HAP at a facility for HAP exceeding the 
proposed thresholds. For the alternative case, the EPA included all HAP 
records at a facility when any HAP exceeded the proposed thresholds. 
Based on these counts, the EPA estimates a 40% increase in burden 
associated with the alterative that the EPA is not proposing.
    The EPA has considered whether a 40% burden increase to collect 
additional HAP data (below risk-based reporting thresholds) from non-
major sources would be warranted. In considering this, the EPA has been 
unable to identify a reason to collect those additional HAP (unlike for 
major sources, which as noted starting in section IV.A.4 of this 
preamble, the Act directs EPA to consider all HAP). While the data 
would certainly be more complete under the alternative approach, the 
risk-based reporting thresholds that the EPA is proposing would provide 
substantially more data

[[Page 54140]]

than the Agency currently has. Rather than impose additional burden, 
the EPA is proposing to require that owners/operators of non-major 
sources would report emissions only when those emissions are greater 
than or equal to the HAP reporting thresholds, presented in Table 1B to 
Appendix A of this subpart, but subject to revision as described above. 
The EPA urges commenters to provide comment to it regarding any factors 
the Agency may have missed in selecting the proposed approach.
    In addition to the burden of the various policy options for HAP 
emissions reporting, the EPA evaluated the distribution of sources 
across communities for informational purposes.\31\ The results in Table 
1 provide three types of areas where facilities emit pollutants in 
amounts that classify those sources as major sources or levels of HAP 
for non-major sources that meet the proposed reporting thresholds of 
this action. Table 1 illustrates the demographic make-up of the 
populations located within 5 km of the facilities that would be 
required to report under the proposed policy options. The demographics 
are based on indicators from the Bureau of Census' 5-year American 
Community Survey (ACS).\32\ The column ``Nationwide'' represents the 
nationwide average percent demographics for comparison. The following 
three columns ``CAP Major,'' ``HAP Major,'' and ``Non-Major,'' 
represent the average percent demographics of the populations living 
within 5 km of the facilities in each group of facilities. For this 
analysis, the EPA used a 5-km distance to try to capture the 
appropriate demographics for near-field exposures. Based on previous 
air dispersion modeling of HAP emissions from over 1,600 facilities in 
22 source categories, the average distance of the maximum individual 
cancer risk (MIR) is about 2 km from the facility. A distance of 5 km 
was chosen because it captures 95 percent of MIR locations for these 
1,600 facilities. Section 6 of the TSD provides additional details. 
Regarding race and ethnicity, the data show that on average, the 
populations living around facilities affected by this action are above 
the percent national average. While the national average population for 
African Americans is 12 percent, the percentage of this demographic 
group near facilities is between 15 and 17 percent, depending on the 
facility type. Similarly, the Hispanic/Latino population average is 19 
percent, and the percentage of this demographic near facilities is 22 
to 23 percent. For the Other Multiracial population, the average 
nationally is 8 percent while the percentage of this demographic near 
facilities is 9 to 10 percent. In addition, the populations living 
around facilities affected by this action are above the percent 
national average for ``Below Poverty Level,'' ``Over 25 and without a 
High School Diploma,'' and ``Linguistically Isolated.'' Since the 
reporting thresholds are largely based on risk contribution, these 
results show that owners/operators will report HAP from facilities 
emitting at levels contributing to risk in both low-income areas an in 
communities with a higher minority population than average.
---------------------------------------------------------------------------

    \31\ This analysis was completed prior to a few minor revisions 
to the NAICS list and emissions thresholds (added 5622xx for Waste 
Treatment and Disposal and 62231x for Specialty Hospitals). No 
facilities are in the 2017 NEI used in this analysis for 62231x. The 
EPA also revised the cobalt threshold after this analysis was done. 
The EPA has reprocessed the facility analysis and about 2,000 
facilities were added since the EJ analysis was completed. The EPA 
believes that the results of the analysis are still highly 
representative of the proposed reporting criteria because the 
analysis included more than 17,700 facilities.
    \32\ U.S. Census Bureau American Community Survey Data, https://www.census.gov/programs-surveys/acs/data.html.

      Table 1--Percent of Population by Demographic for Populations Nationwide and Within 5 km of CAP Major
                           Facilities, HAP Major Facilities, and Non-Major Facilities
----------------------------------------------------------------------------------------------------------------
                                                                                    HAP major:
                                                                    CAP major:      population      Non-major:
                                                                    population    within 5 km of    population
                Demographic group                   Nationwide    within 5 km of       7,552      within 5 km of
                                                                       4,067        facilities         6,096
                                                                    facilities    (including HAP/   facilities
                                                                                    CAP major)
----------------------------------------------------------------------------------------------------------------
Total Population \a\............................     328,016,242      69,683,592     117,946,858      93,000,649
----------------------------------------------------------------------------------------------------------------
                                          Race and Ethnicity by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................              60              50              52              52
African American................................              12              17              16              15
Native American.................................             0.7             0.4             0.4             0.4
Hispanic or Latino (includes white and nonwhite)              19              23              22              23
 \b\............................................
Other and Multiracial...........................               8               9               9              10
----------------------------------------------------------------------------------------------------------------
                                                Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................              13              16              16              15
Above Poverty Level.............................              87              84              84              85
----------------------------------------------------------------------------------------------------------------
                                              Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......              12              14              14              14
Over 25 and with a High School Diploma..........              88              86              86              86
----------------------------------------------------------------------------------------------------------------

[[Page 54141]]

 
                                       Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................               5               8               7               7
----------------------------------------------------------------------------------------------------------------
\a\ The nationwide population and all demographic percentages are based on the Census' 2015-2019 American
  Community Survey 5-year block group averages and include Puerto Rico. The total population count within 5 km
  of all facilities is based on the 2010 Decennial Census block populations.
\b\ To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic category
  for these analyses. A person who identifies as Hispanic or Latino is counted as Hispanic/Latino for this
  analysis, regardless of what race this person may have also identified as in the Census.

    Table 2 below provides the estimated number of known facilities 
from the 2017 NEI expected to be impacted by these proposed HAP 
reporting requirements for which the average percent of the population 
within 5 km exceeds the national average for different demographics. 
These results show that a significant number of the known facilities 
for which the proposed action could collect better data are located 
near areas of interest for environmental justice issues.

  Table 2--Number of Facilities for Which the Population Within 5 km Exceeds the National Average for Different
                                 Facility Categories and Different Demographics.
----------------------------------------------------------------------------------------------------------------
                                                                                     HAP major
                                                                     CAP major      facilities       Non-major
                      Demographic group \a\                         facilities    (includes HAP/    facilities
                                                                                    CAP major)
----------------------------------------------------------------------------------------------------------------
Total Number of Facilities......................................           4,067           7,552           6,096
----------------------------------------------------------------------------------------------------------------
                                               Race and Ethnicity
----------------------------------------------------------------------------------------------------------------
White...........................................................           2,393           4,878           4,306
African American................................................             958           2,608           1,231
Native American.................................................             731           1,287           1,664
Hispanic or Latino (includes white and nonwhite) \b\............             974           1,657           1,396
Other and Multiracial...........................................             679           1,088           1,014
----------------------------------------------------------------------------------------------------------------
                                                     Income
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................           1,812           4,082           2,649
----------------------------------------------------------------------------------------------------------------
                                                    Education
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......................           1,793           3,959           2,606
----------------------------------------------------------------------------------------------------------------
                                             Linguistically Isolated
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................................             811           1,338           1,012
----------------------------------------------------------------------------------------------------------------
\a\ Demographic data are based on the Census' 2015-2019 American Community Survey 5-year block group averages
  and include Puerto Rico. The total population count within 5 km of all facilities is based on the 2010
  Decennial Census block populations.
\b\ To avoid double counting, the ``Hispanic or Latino'' category is treated as a distinct demographic category
  for these analyses. A person who identifies as Hispanic or Latino is counted as Hispanic/Latino for this
  analysis, regardless of what race this person may have also identified as in the Census.

11. Reporting Release Coordinates
    In conjunction with the proposed requirements to report HAP 
emissions, the EPA is considering the need for accurate location 
information of HAP emissions releases to be able to perform 
appropriately detailed assessments of risk using models. The EPA 
estimates concentrations and associated risk from HAP emitted from 
facilities using the AERMOD modeling system \33\ and uses HAP emissions 
in other models for various analyses. These models rely on emissions 
data as input, and the most complete modeling approaches include 
emissions at the many individual release points that can exist at 
facilities. Large facilities can have hundreds of individual release 
locations, and the proximity of those releases to people and 
communities is an important aspect of proper risk estimation for 
populations. Emission releases are

[[Page 54142]]

compiled in the NEI as either stack releases or fugitive releases.
---------------------------------------------------------------------------

    \33\ AERMOD modeling system home page, EPA, https://www.epa.gov/scram/air-quality-dispersion-modeling-preferred-and-recommended-models#aermod.
---------------------------------------------------------------------------

    The EPA proposes a requirement that owners/operators and States 
reporting emissions data directly to the EPA would report release point 
locations that are distinct from the facility location. This proposed 
requirement would apply for both stack locations and fugitive release 
locations. To arrive at this proposed approach, the EPA is considering 
a variety of factors described in this section.
    Stack and fugitive releases in the NEI are already required to be 
reported by the current AERR. In addition, stack parameters such as 
height, release diameter, exit gas temperature, and exit gas velocity 
are also required so that models can simulate the buoyancy of emissions 
plumes and dispersion in surrounding areas. For fugitive releases, the 
current AERR also requires parameters to characterize the shape of the 
fugitive release as 2- or 3-dimensional, the width, length, and height 
of the emissions release, and the orientation of the release shape. In 
both cases, however, the current AERR does not require that release 
point locations be specific to each release point. Rather, it allows 
States to report only the overall facility location, and, in that case, 
the EPA uses the facility location to set default release point 
locations for that facility when States do not provide specific release 
point locations.
    The current AERR approach was promulgated in 2015 (80 FR 8787, 
February 19, 2015). In that final rulemaking, the EPA changed the 
requirement for States to provide X Stack Coordinate (longitude) and Y 
Stack Coordinate (latitude) only at the facility location, rather than 
for the stack locations. In that final action, the EPA explained that 
``most states do not have accurate location values for each individual 
release point within a facility; instead, they frequently report the 
same locations for all stacks within a facility'' (80 FR 8792, February 
19, 2015). In addition, the EPA stated that ``the vast majority of 
facilities are geographically small enough that such a simplification 
does not reduce the usefulness of the data and we encourage States to 
optionally report individual stack locations to add accuracy beyond the 
single facility center location. The EPA may also add such individual 
stack locations where the agency believes it has accurate data'' (80 FR 
8792).
    The context of that AERR revision was within the requirements for 
collecting CAP emissions. The primary use of the NEI for CAP pollutants 
is for Eulerian grid modeling such as the Community Multiscale Air 
Quality (CMAQ) modeling system,\34\ for which emissions sources are 
mapped to grid cells for modeling. These grid cells are typically 4- or 
12-km, which is the context for the statement made in the 2015 AERR 
revision that ``the vast majority of facilities are geographically 
small enough that such a simplification does not reduce the usefulness 
of the data'' (80 FR 8792). For the case of such grid modeling, using a 
single facility-wide latitude/longitude for stacks would at worst, 
misplace some of the emissions from a facility into a neighboring grid 
cell when a facility size is such that it crosses a grid cell boundary. 
Given other modeling uncertainties of Eulerian grid modeling, this 
additional uncertainty would not be a concern for most modeling 
applications in the relatively few cases where it occurred. In cases 
that need more locational detail, the EPA could revise the inventory to 
correct any release point locational inaccuracies caused by the current 
AERR's approach to the release point coordinate requirements. The EPA 
received no comments regarding this revision during the comment period 
for the June 20, 2013, proposed rule (78 FR 37164).
---------------------------------------------------------------------------

    \34\ Community Multiscale Air Quality Modeling System home page, 
U.S. EPA, https://www.epa.gov/cmaq.
---------------------------------------------------------------------------

    In the context of the HAP emissions reporting requirements proposed 
in this action, the EPA is revisiting the requirement for accurate 
release point locations. The EPA's experience with risk modeling using 
HAP emissions inventories has been that using default facility 
locations for all release points provides lower quality results than 
when models use more detailed data. Using imprecise locations can 
provide inaccurate risk information that could overstate or understate 
cancer risk significantly. Research has concluded that improved 
locational data and release parameters can reduce uncertainty in a risk 
assessment by up to 2 orders of magnitude.\35\ These modeling results 
are especially sensitive to the distance between the residential 
receptor and the emission sources, especially for facilities that have 
a large industrial footprint.
---------------------------------------------------------------------------

    \35\ Jing, Q., Venkatram, A., Princevac, M., Pankratz, D., 
Wenjun., Q., Modeling Dispersion of Buoyant Emissions from a Low 
Level Source in an Urban Area, American Meteorological Society, The 
Conference Exchange, 2010. See also https://ams.confex.com/ams/pdfpapers/160624.pdf.
---------------------------------------------------------------------------

    Because risk is very related to proximity of the source to 
populations, when a large facility has emissions releases that border 
neighborhoods, the risk can be greatly understated if EPA were to use a 
single central facility-wide location. The EPA's modeling guidance for 
urban air toxics modeling \36\ explains that ``each source will need to 
be classified as a point, area, volume, or line source,'' and that 
``building the source inventory usually begins with mapping the 
locations of emissions sources.'' Also in the guidance, subsections in 
Section 1.3 indicate how modelers should define each of the different 
types of release points and specify ``location of the source'' (point 
source characterization), ``location, geometry, and relative height'' 
(for 2-dimensional release points, called ``area sources'' in the 
guidance). Likewise, Section 7.2 of the ``Air Toxics Assessment 
Reference Library, Volume 2, Facility-Specific Assessment'' \37\ 
explains that model inputs needed by the Human Exposure Model (HEM) 
require ``the geographical location (latitude and longitude) of each 
source being simulated (with ``source'' in this context being each 
release point at a facility) and states that ``the model requires that 
coordinate data be obtained for each emission source in the analysis, 
and that each emission source is modeled individually.''
---------------------------------------------------------------------------

    \36\ Dispersion Modeling of Toxic Pollutants in Urban Areas and 
Appendices, U.S. EPA, Document No. 454-R-99-021, July 1, 1999; 
https://www.epa.gov/scram/air-modeling-guidance-air-toxics-modeling.
    \37\ Air Toxics Risk Assessment Reference Library, U.S. EPA, 
https://www.epa.gov/fera/air-toxics-risk-assessment-reference-library-volumes-1-3.
---------------------------------------------------------------------------

    As further evidence of this need, EPA has previously found it 
necessary to collect limited sets of this data from certain industries 
to support modeled risk analysis for the Risk and Technology Review 
(RTR) program required by CAA sections 112(f)(2) and 112(d)(6).\38\ 
These one-time requests included collection of release point location 
and other parameters for stack and fugitive releases. As explained 
above in Section IV.A.1, these one-time collections tend to impose 
sporadic and reoccurring ``start-up'' burden on owners/operators 
associated with expending time and resources on understanding and 
responding to the requests. While the mandatory risk reviews under CAA 
section 112(f)(2) have been completed for most of the source categories 
listed under CAA

[[Page 54143]]

section 112, the EPA may conduct future risk reviews that are 
discretionary under the CAA. Further, the EPA does have the continuing 
obligation to conduct a technology review under CAA 112(d)(6) for each 
HAP standard every 8 years. Under this proposal, data for these future 
reviews would already be available to the agency rather than needing to 
issue a continuous and never-ending stream of individual data 
collection requests. Having the data available will allow EPA to be 
timely in meeting these CAA obligations.
---------------------------------------------------------------------------

    \38\ Examples include Plywood and Composite Wood Products 
Manufacturing (https://www.epa.gov/stationary-sources-air-pollution/plywood-and-composite-wood-products-manufacture-national-emission), 
Ethylene Oxide Emissions Standards for Sterilization Facilities 
(https://www.epa.gov/stationary-sources-air-pollution/ethylene-oxide-emissions-standards-sterilization-facilities), and Petroleum 
Refining Sector (https://www.epa.gov/stationary-sources-air-pollution/comprehensive-data-collected-petroleum-refining-sector).
---------------------------------------------------------------------------

    In the previous AERR revision, we identified one reason for the 
change of release point location data to be optional as the lack of 
available information from States. The collection approach proposed by 
this action would avoid this limitation because it would allow for 
owners/operators to directly report release point locations and 
parameters in support of the proposed requirement to collect and submit 
HAP emissions data. As defined by 40 CFR 2.301(a)(2)(i), emissions data 
includes those parameters necessary to characterize the emissions, 
which, in the context of HAP emissions, includes the release locations 
and parameters required in Table 2a to Appendix A of Subpart A of Part 
51.
    Another relevant consideration for release point locations is the 
ease with which such data can be obtained now. Global Positioning 
System (GPS) applications are readily available on ubiquitous cell 
phones for employees of both small and large companies to compile such 
information. For stack releases, coordinates for the center of a stack 
can be readily obtained either with a GPS approach or using readily 
available online mapping software to pinpoint the locations of stacks 
and fugitive releases.
    Based on these considerations, the EPA proposes that any owners/
operators reporting emissions data directly to the EPA (other than 
small entities as per section IV.A.12 of this preamble) would be 
required to provide specific release point locations that are distinct 
from the facility location. Considering the complexity of facilities 
and that release points frequently emit both CAPs and HAP, the EPA 
proposes that this requirement be applied to all release points 
reported in the facility inventory (i.e., not only those release points 
that emit HAP). In addition, to keep the quality assurance of the 
incoming data manageable, this approach will allow the EPA to have 
detailed release parameter data for SO2 and 
PM2.5, which also can be modeled using AERMOD and fine-scale 
modeling tools as part of permitting and other NAAQS programs. To be 
consistent with requirements across the inventory collection process, 
the EPA additionally proposes that State programs would be required to 
report all release points using release point locations that are 
distinct from the facility location. These proposed requirements apply 
for both stack locations and fugitive release locations.
12. Reduced HAP Reporting Requirements for Small Entities
    In developing this proposal, the EPA convened a Small Business 
Advocacy Review (SBAR) Panel in compliance with section 609(b) of the 
Regulatory Flexibility Act (RFA) as amended by the Small Business 
Regulatory Enforcement Fairness Act of 1996 (SBREFA). In addition to 
EPA's Small Business Advocacy Chairperson, the SBAR Panel consisted of 
the Director of the Air Quality Assessment Division of OAQPS, the 
Administrator of the Office of Information and Regulatory Affairs 
(OIRA) within the OMB, and the Chief Counsel for Advocacy of the Small 
Business Administration (SBA). The SBAR Panel recommended many 
accommodations for small entities to reduce their burden while still 
allowing this proposal to collect data needed to meet EPA's objectives 
under the Clean Air Act. A copy of the full SBAR Panel Report is 
available in the docket for this action.
    The SBAR Panel recommended, among other things, that the EPA 
propose allowing any small business subject to revised reporting 
requirements under this proposal to report aggregated emissions for the 
facility as a total fugitive emissions value rather than the detailed 
emissions by process and release point. Since the EPA is not proposing 
to change reporting thresholds for criteria pollutants, this 
recommendation only applies to HAP emissions reporting and any 
incidental CAP emissions (as described in section IV.A.10 of this 
preamble).
    During the SBAR Panel, the EPA observed that risk modeling using 
facility total emissions would be more conservative than using more 
detailed emissions that could include stack releases, because all 
emissions would be modeled as ground-level fugitive emissions. With 
more specific data about emissions releases (e.g., through stacks 
raised above ground level), the modeling includes more dispersion of 
pollutants that can lower modeled concentrations at the ground level 
thereby lowering modeled risk. The EPA additionally observed that if 
modeled risk from facility total emissions were high enough, the Agency 
would have an interest in collecting more detailed data to better 
assess risk. While aggregated data (facility total emissions) are not 
as useful to the EPA as the more detailed data, this approach balances 
EPA's needs for these data with the burden on small businesses. Under 
this proposed approach, EPA's available data is less complete, although 
still helpful, and the burden on small businesses is reduced when 
compared to the requirement to report the full suite of detailed data 
that the EPA is proposing to require for other sources that are not 
small businesses.
    In addition, because States are free to have emissions collections 
that include sub-facility detail irrespective of any final AERR 
provisions, States may collect more detailed data than would be 
required by the AERR. The EPA observes that EPA, States, and owners/
operators have a shared interest in ensuring that the EPA has the more 
detailed data to support risk assessment and other work.
    Based on these considerations, the EPA proposes to provide owners/
operators the option to report a facility's total emissions instead of 
the detailed data otherwise required when: (1) they meet the small 
entity definition as proposed by this action, (2) the owner/operator 
has never been notified that the EPA has modeled a cancer risk for the 
facility of 20/million or more, or the EPA has made such a notification 
less than 180 days prior to the next point source emissions reporting 
deadline, and (3) estimates of emissions with the process-level detail 
that would otherwise be required by this proposed action are not 
required by a State.
    The EPA is considering the facility total cancer risk level above 
which an owner/operator would not be able to use the optional facility-
total reporting accommodation (item 2 in the previous paragraph). The 
cancer risk level range under consideration is from cancer risk of 1/
million, which is the level used to develop the proposed emissions 
reporting thresholds for HAP to 100/million, which is a level the EPA 
uses to help formulate emissions reductions strategies as part of 
NESHAPs and other HAP regulatory programs. In addition, the EPA is 
considering the degree of uncertainty that can exist when estimating 
risks through modeling and is recommending that a modeled cancer risk 
between 10/million and 30/million would be appropriate to warrant more 
detailed emissions reporting. Using a cancer risk of 1/million for this 
purpose would not provide much burden reduction because 1/million is 
the basis of the proposed HAP reporting thresholds, above which non-
major sources would need to report. Beyond a

[[Page 54144]]

cancer risk of 30/million, the upper uncertainty range is more likely 
to reach 100/million, for which the EPA certainly needs better HAP 
data.
    As previously noted, the EPA is proposing that if its modeling 
shows 20/million or more cancer risk, small businesses would need to 
report more detailed emissions. EPA is taking comment on a cancer risk 
range of 10/million to 30/million for this potential threshold. In this 
proposed cancer risk range for comment, the EPA is considering that 
this range represents a 10-fold to 30-fold accommodation for small 
businesses beyond achieving less than 1/million cancer risk as laid out 
for EPA in the CAA. The target of cancer risks of 1/million or lower is 
included at CAA 112(c)(9)(B)(i), which describes that the EPA may 
delete a source category from the list of categories if, among other 
requirements, the EPA determines that no source in the category emits 
HAP in quantities which may cause a lifetime 1/million risk of cancer. 
Likewise, CAA 112(f)(2)(A) directs EPA to promulgate emissions 
standards that ``shall provide an ample margin of safety to protect 
public health'' and to promulgate standards beyond standards set by CAA 
112(d) if those standards ``do not reduce lifetime excess cancer risks 
. . . to less than one in one million.''
    The EPA encourages commenters to provide feedback on the proposed 
choice of the midpoint of this range of 20/million estimated cancer 
risk to provide accommodations to small businesses. The EPA seeks to 
learn about any considerations that the EPA may have failed to consider 
in proposing this midpoint.
    In addition to allowing for facility-wide reporting in certain 
situations to reduce burden on small entities, the EPA is considering 
how best to reduce burden for reporting the facility inventory. For 
owners/operators that are not small entities, the current AERR requires 
States to report the attributes for the facility (e.g., name, address) 
as well as component attributes for emissions units, release points, 
processes, and controls. These data elements are required under the 
current AERR, but States report the facility inventory separately from 
emissions because facility attributes do not vary every year. After the 
first report for a facility, States under the current AERR and States 
and owners/operators under these proposed revisions would need only to 
report modifications to the facility inventory after the first year. 
For example, if a facility adds or removes a unit, then those changes 
would be submitted but the other facility attributes could likely be 
retained without resubmission. In the case of facility-wide emissions 
reporting, the facility inventory would not necessarily need sub-
facility data to support the emissions reports, since emissions would 
not need to be allocated to the units and processes within the 
facility.
    In addition to the facility total emissions, the EPA needs to know 
which units are present at facilities and which units are subject to 
NESHAPs or other air emissions regulations. As described in section 
IV.I.8, the EPA is proposing that States and owners/operators of 
permitted sources would be required to provide the regulatory codes 
that apply to units and/or processes. To fulfill EPA's need for this 
information while reducing burden, the EPA is proposing that small 
entities would only need to report a list of their units, including all 
required unit-level data elements. This would reduce burden while still 
allowing the EPA to identify which units at each facility are subject 
to regulations.
    The EPA provided an analysis for the SBAR Panel that estimated the 
number of small entities expected to report based on EPA's proposed HAP 
emissions reporting thresholds. This analysis showed that the collision 
repair industry characterized by NAICS 811121 (Automotive Body, Paint, 
and Interior Repair and Maintenance) is unique in that it has the most 
small entities of any industry that the EPA is considering including in 
the proposed rule according to the 2017 Economic Census data, and that 
much smaller number of the largest collision repair facilities (about 
2,000) are estimated to fall within the emissions reporting thresholds 
under consideration. Given that the EPA is already receiving data 
through States from about 2,300 of such sources, the EPA is unlikely to 
reduce the number facilities for which emissions data must be reported 
below the number it is already receiving. The EPA reviewed other NAICS 
in this way, but no other NAICS presented a similar situation. In other 
industries, the EPA either estimates that many more sources would need 
to report based on these proposed requirements or the EPA lacks 
sufficient existing emissions data for facilities with those NAICS to 
perform the same analysis.
    To balance the potential burden with the need for information and 
considering the large number of businesses in the collision repair 
industry, the SBAR Panel recommended that the EPA consider explicitly 
excluding small entities in the collision shop industry from new 
reporting requirements. Such an approach would still collect HAP data 
from many more facilities than are available to the EPA currently, 
while not burdening small entities. To address this panel 
recommendation, the EPA proposes to exclude small entities (except for 
major sources) with primary NAICS 811121 from any HAP reporting 
requirements under the AERR. This proposal reflects this accommodation 
in Table 1C of Appendix A of this subpart, which lists primary NAICS 
codes subject to non-major source HAP reporting requirements.
    Another concern identified during the SBAR Panel was that small 
entities that are not already reporting emissions data to the EPA or a 
State may not have the necessary experience and resources to develop 
emissions estimation approaches where none are readily available. The 
SBAR Panel additionally noted that small entities would have the lowest 
burden when the EPA provides an emissions estimation method or there 
are already some other readily available emissions estimates to use 
because that business must report emissions to the State or TRI. The 
SBAR Panel Report also noted that small entities may have source test 
data with which emissions estimates could be made. The Panel 
recommended that, consistent with these concerns, a small entity would 
not be expected to report emissions for pollutants when the EPA does 
not provide a way to estimate emissions and there is no other readily 
available data for that pollutant.
    The EPA is considering how best to address these SBAR Panel 
recommendations. For current AERR requirements regarding State 
reporting, the EPA does not address the availability of emissions 
estimation methods for facilities. The presumption of the current 
regulations is that States, in collecting data from facilities to 
report to EPA, would ensure that the requirements to report all CAP are 
met when any CAP exceeds the reporting threshold, irrespective of 
whether the EPA provides an emissions calculation method.
    The EPA has observed in working with States under the current AERR 
that many States rely on the EPA WebFIRE database for emissions factors 
for use by owners/operators to calculate emissions in State collection 
systems. In the absence of source test data or site-specific emissions 
factors created by the facility, the collections would therefore use an 
EPA approach and when none is available, would be less likely to report 
the pollutant. Many States with HAP collection programs have also 
developed emissions factors, and State reports for many HAP include 
emissions

[[Page 54145]]

based on these State factors. As a general matter for emissions 
reporting under the current AERR, when EPA, a State, or a trade 
association does not provide emissions calculation methods for a 
process/pollutant combination (even when emissions from such a 
combination is likely to exist), the EPA has observed that emissions 
data reported by States is much less likely to include emissions for 
that process/pollutant combination.
    Based on this experience, the SBAR Panel recommendation is 
consistent with EPA's understanding of the practical reality of the 
data collection process for all businesses currently reporting to 
States. Namely, when EPA, States, or trade associations do not provide 
an emissions calculation method for a given process/pollutant 
combination and owners/operators do not have source tests or other 
readily available data, emissions reports do not include emissions for 
those process/pollutants. The EPA recognizes that this could be 
occurring irrespective of whether those processes/pollutants are 
required to be reported under the current AERR and State programs. As 
described in the next section, the EPA intends to provide an emissions 
estimation tool for small entities to use in support of implementing 
the proposed requirements. The emissions estimation tool would provide 
a way for small businesses to estimate their facility-wide emissions to 
assess whether their emissions exceed the non-major HAP emissions 
reporting thresholds. If they do exceed the thresholds and the owner/
operator determines they must report, the emissions estimation tool 
would allow those estimates to be submitted to EPA (and States) via 
CAERS. The EPA expects that providing this tool will assist with 
reducing situations where required data are not reported. In this 
section, the EPA also addresses how development and use of this tool 
would lessen the burden on small entities if the provisions of this 
proposal were finalized.
13. Emissions Estimation Tool for Small Entities
    The SBAR Panel recommended that the EPA develop an emissions 
estimation tool to help small entities estimate facility-wide 
emissions. The emissions estimation tool could be used by small 
entities to help them determine if their facility-wide emissions are 
above HAP reporting thresholds and to provide an emissions value for 
small entities to submit when emissions exceed the reporting 
thresholds. The SBAR Panel recommended that the EPA adopt emissions 
estimation approaches that rely on information that small entities can 
readily gather in the normal course of business.
    To address these recommendations, the EPA plans to develop an 
emissions estimation tool to help small entities estimate facility-wide 
emissions. The EPA would develop this tool between the time this rule 
is proposed and the first year of any new point source reporting (see 
section IV.F of this preamble for timing information). While CAP 
emissions may be included in this tool, the EPA would prioritize HAP 
emissions because other than the addition of incidental CAP to 
reporting requirements, the EPA is not considering changing CAP 
reporting thresholds with this proposal. The emissions estimation tool 
would include incidental CAPs as relevant, depending on the HAP. The 
greatest, and most urgent, need for assistance will be for those small 
entities that do not have to report for any pollutants under the 
current AERR.
    With this tool in mind, the EPA is considering the SBAR panel 
recommendation described in section IV.A.12 of this preamble that the 
EPA should not expect small entities to develop new emissions 
estimation approaches when none are available. The EPA agrees in 
principle with this recommendation but also wants to maintain a 
straightforward but flexible implementation of the proposed 
requirements. The EPA has proposed the criteria for point source 
reporting to include major source status, and for non-major sources, 
primary NAICS codes and emissions levels. The EPA believes that adding 
a regulatory exemption based on emissions estimates generated by a yet 
to be established and evolving tool would add unnecessary complexity to 
the structure of the rule. This is in part because States can choose to 
report HAP on behalf of owners/operators. Thus, if the planned tool 
were to provide a regulatory exemption, States could also be expected 
to rely on EPA's tool, limiting their autonomy for implementation of 
HAP reporting requirements. While additional considerations could be 
included in a proposed rule to avoid that limitation, the EPA expects 
that such additions would add complexity and confusion that the EPA is 
seeking to avoid. Further, such a regulatory exemption which relied on 
use of such a tool could increase the burden on small entities (i.e., 
could increase recordkeeping and reporting burden compared to the 
current proposal).
    Further, given EPA's observations that common practice under the 
current AERR is for States and owners/operators to rely on EPA, State, 
or trade association emissions estimation approaches when better 
information is not available, a logical conclusion is that this 
situation would continue to occur under these proposed revisions to the 
AERR. The EPA would expect that in circumstances where better data were 
available for estimating emissions, the emissions estimation tool would 
not be used. Such an approach would be consistent with the planned AERR 
requirement to use the best available emission estimation methods (see 
section IV.I.6 of this preamble). Similarly, when emissions estimates 
are made by an owner/operator for TRI or to meet State requirements, 
those emissions would be appropriate for reporting emissions to the EPA 
under these proposed requirements. The EPA emissions estimation tool 
could be used when these other emissions estimation approaches are not 
available, including when a State is also relying on EPA's tool to 
support owners/operators reporting to them, so States can report to the 
EPA on their behalf.
    When none of these other emission estimation approaches are 
available, and no emissions are estimated by the emissions estimation 
tool, the EPA would not expect owners/operators of small entities to 
develop their own emissions reporting approaches because the burden 
associated with doing so is not warranted. If the EPA is sufficiently 
concerned about an emissions source, then the EPA could develop an 
emissions estimation approach and include it in its emissions 
estimation tool to assist small entities. The EPA could do so using 
other data available from larger businesses including emissions reports 
and source test data (as described in section IV.C of this preamble), 
or if needed, issue a specialized data collection separate from this 
proposed rule.
    The SBAR Panel had many additional recommendations about the 
development and outreach associated with an emissions estimation tool. 
It recommended that the EPA work with small entities and trade 
associations to develop emissions estimation tools that would properly 
reflect the emissions processes and pollutants associated with each 
industry. It also recommended that as the EPA incorporates new 
information into its emissions estimation tool, the EPA should provide 
that information for industry and other parties to review and provide 
feedback. In addition, the SBAR Panel recommended that the EPA should 
provide adequate time for such feedback and for revising the tool based

[[Page 54146]]

on the feedback, dissemination, and training before requiring a new 
tool to be used for any given emissions reporting year. It further 
recommended that the EPA coordinate with Small Business Environmental 
Assistance Programs (SBEAPs) in each State to support the outreach and 
developing guidance for small entities. Finally, the SBAR panel 
recommended that the EPA provide a list of units and processes for 
which small entities could select for emissions reporting for review 
and feedback.
    As previously described in section IV.A.12 of this preamble, the 
EPA is proposing to provide an optional accommodation for small 
entities to report emissions as a facility total under certain 
conditions and is proposing that the accommodation would not be 
available if EPA's risk modeling shows estimated cancer risk of 20/
million or more. If a final rule were to exclude the proposed 
accommodation for facility-total emissions reporting, the SBAR panel 
recommended that the EPA make sure that, when requiring emissions to be 
provided for higher level of detail, emissions calculation methods are 
available for use by a small entity that reports for any such facility.
    To address the development and outreach recommendations of the SBAR 
Panel, the EPA is considering an ongoing development and review 
approach for the emissions estimation tool. First, in developing the 
initial tool prior to any new reporting for small entities, the EPA 
would consult with the public including industry representatives and 
other interested parties. This initial development would begin sometime 
after receiving comments on this proposal and would end prior to the 
first deadline for point source reporting under any revised 
requirements. The EPA would include in the tool emissions factors from 
a variety of sources. For the initial release of the tool, the EPA 
plans to provide the tool and underlying data at least 12 months before 
the first reporting deadline, giving 3 months for feedback. The EPA 
would consider such feedback and incorporate changes in the tool before 
releasing the initial version of tool in advance of any new reporting 
deadlines for small entities.
    The EPA expects that development of the tool would evolve 
iteratively each year. The EPA would plan to release any revisions to 
the tool each year for public review and feedback and adjust the tool 
in advance of the next emissions inventory reporting deadlines. If the 
use of the tool changed, the EPA would update the training materials. 
This iterative approach would be coordinated with the ongoing iterative 
CAERS development approach that the EPA has been using very 
successfully for the past 3 years. The EPA would plan to funnel 
outreach for these efforts through SBEAPs within each State.
    The EPA is considering how best to implement such an emissions 
estimation tool. Currently, the EPA is considering first ensuring that 
it includes key industrial processes that can be estimated at a 
facility level, relying on activity information that is readily 
available to small entities. Such industrial processes might be fuel 
combustion, solvent evaporation, and activities that create toxic 
dusts. Emission rates would depend on whether emissions controls are 
present and the type of controls if present. Emission factors would be 
used to translate some activity measure at a facility (e.g., fuel 
usage) to emissions. To use such an estimation tool, an owner/operator 
would need to (1) identify its emitting activities from a list that the 
EPA would provide and (2) enter total facility information for fuels, 
other materials, energy used, or other information that could even 
include the number of employees. The type of information used in the 
emissions estimation tool would depend on the available data for each 
emitting activity. The tool would show the estimated emissions levels 
and which ones (if any) were above the reporting thresholds.
    The EPA is also considering the possibility of misuse of the tool 
by owners/operators to avoid reporting responsibility. For example, we 
have considered the possibility that an owner/operator might 
intentionally enter low activity data into EPA's tool to ensure 
emissions were below the applicable reporting threshold. The EPA's 
conclusion is that this would violate the requirement under Sec.  
51.5(a) of this proposed rule to use the best available information to 
estimate emissions. Further, if the facility was actually emitting at 
or above the applicable reporting threshold but not reporting those 
emissions, that too would be a violation of the proposed requirements. 
The EPA plans to develop this tool to assist facilities with 
determining whether they emit at or above the applicable reporting 
threshold (and thus would be required to report) and to help them 
estimate emissions for reporting. Use of the tool, however, does not 
excuse an owner/operator, or a State, from complying with all 
applicable requirements. As part of using the tool, owner/operators 
would need to follow the directions provided as part of the estimation 
tool. The EPA also expects the tool would include a mechanism for users 
to indicate that the information entered is complete and accurate to 
the best of their knowledge. In addition, to avoid future 
misunderstandings, the tool would create an electronic report that 
would include the name and business of the person using the tool, the 
input data entered by the user, the resulting facility-wide emissions, 
and whether any of those emissions exceed an emissions reporting 
threshold. This information would not be collected by the EPA in the 
first instance, unless the report was submitted as an emissions report 
to the EPA either voluntarily or because the owner/operator has 
determined that it is required to report. However, we anticipate that 
future EPA directions, or guidance, associated with using the tool 
could recommend that owners/operators retain these reports and/or other 
information they used for assessing facility-wide emissions to 
determine whether they must report.
    If a small business determines that emissions estimates exceed one 
or more HAP reporting thresholds, those facility-wide emissions could 
be reported to the EPA to meet reporting requirements, so long as the 
small business meets the conditions that permit optional facility-wide 
emissions reporting. The EPA intends to make the reporting of the tool 
emissions values easy for small entities by providing for an automatic 
transfer of information already entered into the emissions estimation 
tool into the CAERS reporting forms. This approach would further reduce 
burden on small entities. Finally, during any such submission, the EPA 
expects that CAERS would support an official certification that the 
information provided is complete and correct, consistent with EPA's 
certification requirements for electronic data collection.
14. Definition of Small Entities
    To implement the small business accommodations described in section 
IV.A.12 of this preamble, the EPA is proposing a definition of small 
entity to be consistent with CAA Section 507(c). This definition limits 
small entities to those that meet all of the following criteria: (a) 
has 100 or fewer employees, (b) is a small business concern as defined 
in the Small Business Act (15 U.S.C. 631 et seq.), (c) is not a major 
source, (d) does not emit 50 tons or more per year of any regulated 
pollutant, and (e) emits less than 75 tons per year or less of all 
regulated pollutants. The SBA small business concern size standards are 
available at 13 CFR121.201.

[[Page 54147]]

    EPA is proposing this definition for two primary reasons. First, 
excluding major sources from the definition best supports the needs for 
data from major sources as previously described in sections IV.A.1 
through IV.A.3 of this preamble. EPA's obligations under the CAA 
require process-level data from major sources, including control 
technologies employed. Using this definition, the proposed 
accommodations for small entities would not interfere with getting that 
necessary data from major sources.
    Second, these proposed requirements are for record keeping and data 
reporting, which have much lower burden associated with each facility 
than would a proposal that includes requirements to install control 
devices. EPA's estimated yearly average per-facility burden for 
reporting emissions data starting in 2027, is just 27 hours when using 
in-house personnel to accomplish emissions reporting.\39\ This number 
of hours is reasonable given the information that would be collected 
and its importance to EPA analyses in support of the public interest. 
While still ``small'' under the SBA definition, larger facilities 
(i.e., those with more than 100 employees) could be more likely to emit 
pollutants at levels of environmental risk of concern and interest by 
EPA. The EPA would be able to use the additional process-level 
emissions data from these facilities to improve understanding of 
emissions from small entities at the process level and to include such 
sources in EPA's Technology Reviews.
---------------------------------------------------------------------------

    \39\ See Appendix A, Table A-2 of the Supporting Statement for 
the Air Emissions Reporting Requirements (AERR) EPA ICR # 2170.09 
for this proposal, available in the docket for this action.
---------------------------------------------------------------------------

    Even so, the EPA is considering whether the CAA definition for 
small entities is the most appropriate because it does not provide as 
much burden reduction as would a definition based in part on the SBA 
definition. For the primary NAICS under consideration to define non-
major sources for this proposal, the SBA definition includes owners/
operators with between 200 and 1,500 employees, and for certain NAICS 
define small businesses based on the annual receipts of the company 
between $8 million and $41.5 million. As part of the SBAR Panel 
process, the EPA estimated the number of small entities that could be 
affected by the rule using a definition based on 100 employees for all 
NAICS codes as compared to a definition based on the SBA NAICS-specific 
thresholds. More details on the analytical approach are available in 
the supporting materials to the SBAR Panel Report included in the 
regulatory docket for this proposal. The EPA updated the SBAR Panel 
analysis with the final NAICS and reporting thresholds included in this 
proposal, and the analysis results are included in the TSD for this 
proposal. Through this analysis, the EPA estimates that using a 
definition of 100 employees would require reporting for about 34,000 
small entities, allowing them to use the proposed small business 
accommodations. That same analysis estimated that using the SBA small 
entity definition would require reporting from about 43,000 small 
entities. This analysis is limited by the available data because the 
100-employee threshold that is used to represent the CAA small entity 
definition does not reflect the exclusion of major sources or the 
emissions-based criteria that are part of the CAA definition. As such, 
EPA's estimate of 34,000 most likely overestimates the number of 
additional small entities that would be subject to the proposed AERR 
revision, in part because some major sources are also small entities.
    Given this information, the EPA is considering a ``SBA Definition 
Alternative'' that would modify the proposed definition to replace the 
100-employee threshold with the NAICS-based thresholds available from 
the SBA definition. This alternative would still exclude major sources 
from being within the definition of small business but would include 
more non-major small entities in the definition. The EPA encourages 
commenters to provide information about benefits of the reduced burden 
on more owners/operators in comparison to the reduced data detail that 
the EPA would have available to estimate risks and analyze for purposes 
including Technology Reviews.
15. Reporting HAP and CAP for the Same Emissions Processes
    Under the current AERR relying on voluntary HAP reporting by 
States, the EPA has observed that some States report CAPs and HAP using 
separate unit and/or process identifiers for pollutants emitted from 
the same process. For example, a State could report emissions for a 
boiler burning oil using process identifier ``1'' to report VOC and 
process identifier ``2'' to report benzene, when in fact both 
pollutants are emitted from the same process and therefore should use 
the same process identifier. Downstream analytical steps that utilize 
emissions inventories rely on computer processing because of the 
hundreds of thousands to millions of data records included in point 
source inventories. The computer software uses the process identifier 
as one of the unique emissions source identifiers. In this example, the 
software would treat the VOC and benzene as if they were emitted from 
two sources at the facility, rather than from a single process for the 
boiler.
    For many uses of emissions inventories, inconsistent process-level 
identifiers pose no problem, but the situation can create some 
problems. First, it complicates QA of the inventory, such as 
identifying whether certain expected pollutants may be missing from 
processes and ensuring that the inventory includes consistent 
information across pollutants for the same process, such as the source 
classification code (SCC). Second, using different SCCs for the CAPs 
and HAP emitted from the same process (but not reported at the same 
process) could cause a miscalculation of co-pollutant impacts from 
emissions controls. For example, when a computer program processes an 
emissions inventory for control strategy development, that program 
would not recognize that a VOC emissions control device assigned at the 
process level should also impact the benzene emissions because benzene 
is a part of VOC. This problem could occur due to mismatched process 
identifiers, SCCs, or both. Third, chemical speciation calculations on 
emissions inventories can be adversely affected by inconsistent 
process-level reporting, because HAP emissions can be used to improve 
the chemical species of CAPs for use in models. Using the VOC and 
benzene example, when the VOC and benzene are reported with different 
processes, then the computer software could not use the reported 
benzene to inform the chemical speciation of the VOC from the same 
process.
    To address these considerations, the EPA proposes to include at 40 
CFR 51.40(b) a provision stating that when reporting process-level 
emissions data, States and owners/operators would be required to use 
the same unit, process, and release point identifiers for all 
pollutants emitted from the same unit, process, and release point at 
the facility. Such an approach allows inventory users to better 
understand the full suite of pollutants for each process, enabling 
improved ability to consider ancillary benefits or the potential for 
unintended adverse impacts of controls on co-pollutants from the same 
process.
    To address the recommendations of the SBAR Panel Report, this 
proposed requirement would not apply to small entities that elect to 
report HAP emissions as a facility total as per the

[[Page 54148]]

proposed accommodations described in section IV.A.12 of this preamble. 
In this case, small entities would not report HAP at the process level 
and the need for a process identifier would not apply. Thus, if a 
facility owned by a small business meets the AERR CAP reporting 
thresholds, then a State would need to collect CAPs from the small 
business and report them to EPA. If the State collects HAP on behalf of 
the same facility in accordance with these proposed requirements, then 
the EPA is proposing that the State would need to allow the small 
business to report HAP as a facility total. However, if the State 
collects HAP on behalf of the facility and the State reporting 
requirements include mandatory process-level reporting (i.e., going 
beyond these proposed requirements), then the State would be expected 
to report the process-level emissions to EPA.
16. Option To Include PFAS as a Required Pollutant
    The EPA is considering whether this action should include reporting 
of per- and polyfluoroalkyl substances (PFAS). PFAS compounds are 
persistent in the environment and accumulate in body tissues, and 
exposure to PFAS compounds has been linked to adverse health effects in 
humans and animals. There are currently no health benchmarks for the 
inhalation toxicity of PFAS compounds; however, PFAS point source 
emissions into air can deposit PFAS into nearby drinking water bodies. 
The EPA has derived chronic, noncancer reference doses (RfD) for oral 
exposure to perfluorooctanoic acid, perfluorooctyl sulfonate, GenX, and 
perfluorobutane sulfonate, with assessments for several additional PFAS 
compounds in progress. While PFAS are not currently HAP, current 
evidence suggests a need for better identification and characterization 
of PFAS point source emissions in air.
    The EPA's 2021 PFAS Strategic Roadmap tasked the Office of Air and 
Radiation with building the technical foundation to address PFAS air 
emissions, in part by identifying PFAS sources and developing 
monitoring approaches for stack emissions. Certain PFAS were added to 
the TRI chemical list under section 7321 of the National Defense 
Authorization Act (NDAA) for Fiscal Year 2020. The NDAA sets the 
reporting threshold for individual PFAS compounds at 100 pounds (i.e., 
0.05 tpy). As previously described for HAP, TRI does not provide the 
level of detail needed for detailed modeling for PFAS.
    EPA also is considering the limitations in our understanding of 
PFAS. For example, measurement methods are unavailable to measure many 
of the individual compounds making up the collective group of PFAS 
compounds. While the EPA continues to develop additional measurement 
methods and more such methods will be available over time, they are not 
available currently. Additionally, toxicity data are available for only 
a handful of compounds in this group currently, but ongoing EPA work in 
this area is expected to provide additional toxicity data in the 
future. These limitations would need to be accommodated by any 
regulations concerning the reporting of PFAS. For example, while the 
EPA has done risk analysis to support the threshold levels for 
reporting HAP (described in IV.A.8 of this preamble), the EPA does not, 
at this time, have sufficient PFAS and risk data to use a similar 
approach for PFAS. The Agency must therefore find another approach to 
propose reporting thresholds for PFAS if it were collected under this 
subpart. As with other pollutants as described in sections A.4 and 
IV.I.6 of this preamble, EPA is proposing that owners/operators would 
not need to measure PFAS emissions if measurements were not already 
available. Rather, owners/operators would be required to use PFAS 
source measurements for annual emissions reporting purposes when 
available and use estimation techniques for reporting when measurements 
are not available.
    Given these considerations, the EPA seeks comment on the following 
``PFAS Option'' for how the Agency could include PFAS reporting 
requirements in a final action. Regulatory text to implement this 
option is described and included here in the preamble. First, the title 
of proposed 40 CFR 51.12(b) would be changed to ``Hazardous air 
pollutants and Per- and Polyfluorinated Substances.'' Second, EPA would 
include at the end of proposed 40 CFR 51.12(b)(1) ``and PFAS as listed 
in Table 1E to Appendix A of this subpart.'' The EPA would additionally 
add Table 1E to list the PFAS subject to reporting, consistent with the 
PFAS list included as part of the TRI. The EPA would further add 
paragraph (3) to proposed 40 CFR 51.12(b) to read ``For point sources 
other than major sources, reported PFAS must include any pollutant 
listed in Table 1E to Appendix A of this subpart when the annual actual 
emissions of that pollutant or pollutant group is greater than or equal 
to the PFAS reporting threshold.'' The threshold would be 0.05 tpy of 
total emitted PFAS-based on the TRI requirements set by Congress.\40\ 
Finally, the EPA would change proposed 40 CFR 51.15(1) to read ``If the 
EPA has approved a HAP and PFAS reporting application as per Sec.  
51.1(d)(2) and Sec.  51.1(d)(3) of this subpart, a State must report 
emissions of HAP and PFAS consistent with Sec.  51.12(b) and (c) of 
this subpart. A State may report one or more HAP or PFAS voluntarily 
through the 2025 inventory year and may not report HAP or PFAS without 
an approved application starting with the 2026 inventory year.''
---------------------------------------------------------------------------

    \40\ See Section 7321 of the National Defense Authorization Act 
for Fiscal Year 2020, Public Law 116-92 (Dec. 20, 2019). There, the 
threshold for reporting is expressed as 100 pounds which is 
equivalent to 0.05 tons.
---------------------------------------------------------------------------

    The EPA recognizes that aligning with the TRI requirement sets a 
reporting threshold for the purposes of the AERR that uses the same 
value for a different purpose, because the TRI reporting threshold is 
based on single PFAS manufacturing, processing, and otherwise use of 
the given PFAS and therefore may not capture emissions from sources 
with cumulative PFAS emissions in air greater than or equal to 0.05 
tpy. Nevertheless, this PFAS Option, if included in the final rule, 
would set an air emissions reporting threshold at the 0.05 tpy level.
    By proposing this threshold for the AERR, the EPA is aligning the 
thresholds as best as possible to reduce complexity and burden. The 
EPA's proposed approach for the AERR is a less stringent threshold than 
the TRI threshold because facilities that manufacture, process, or 
otherwise use PFAS would likely not emit all of that material to the 
air. As such, the EPA is not adding any burden on facilities to 
recognize that they may need to report to the AERR, but rather to 
estimate their PFAS emissions at the level of detail proposed. 
Collecting PFAS emissions data using these proposed requirements could 
be a step towards meeting OAR's goals from the EPA PFAS Strategic 
Roadmap. The EPA is soliciting comment on the PFAS option for including 
mandatory reporting on PFAS in the final rule.

B. Collection of Emissions From Point Sources Not Reported by States

    The EPA's mission includes protecting human health and the 
environment for the entire population, and emissions inventory data are 
a foundational piece of such work. To meet this mission, the EPA 
intends for the NEI to be a complete accounting of emissions from all 
facilities that meet the point source reporting thresholds defined by 
this subpart; however, this objective cannot be met when certain

[[Page 54149]]

facilities are not included. Furthermore, the communities near such 
facilities may not have equitable access to emissions data about those 
facilities when compared with other communities. The EPA cannot account 
for the impacts of those sources on their communities without the same 
detailed emissions data as is available for other sources. The EPA has 
identified cases in which point source emissions are not included in 
the NEI, even though their PTE or actual emissions exceed the CAP 
reporting thresholds in the current AERR. In all cases, the EPA 
proposes that owners/operators would report both HAP and CAP data to 
the EPA under this subpart. The HAP reporting provisions described in 
section IV.A of this preamble apply to such owners/operators; 
therefore, this section addresses several cases where CAP emissions 
would also need to be reported and clarifies reporting requirements for 
facilities operating in Federal waters.
    The EPA is proposing regulatory revisions to address these issues 
for two reasons. First, the EPA created the NEI program using input 
from many stakeholders and is considering updates to the AERR based on 
additional input. For example, the EPA Regional offices have noted the 
lack of emissions data in some areas of Indian country and the resource 
challenges that some tribes have, which make it difficult for a tribe 
to apply for TAS or to collect emissions data. Regional offices 
adjacent to areas of Federal waters with offshore oil activity, fish 
processing ships, deep water ports, and wind turbine construction have 
also noted the lack of emissions data for those activities. Second, the 
cases of missing facilities described above impede the ability of the 
Agency to meet its mission because it does not have the foundational 
data about emissions sources necessary to assess impacts from those 
sources, among other limitations. In addition, since emissions from 
more sources could be reported because of the HAP requirements of this 
proposed action, the problem of missing sources could expand if not 
addressed by this proposal.
1. Facilities on Land Not Reporting Under the Current AERR
    As previously described in section III.A.3 of this preamble, some 
facilities are not reported because the facility is not located within 
the geographic scope of the State's (defined previously in this 
preamble to include local agencies and tribes that have obtained TAS 
for submission of emission inventories) implementation planning 
authority. This can occur, for example, for a facility that operates 
within an Indian reservation for a tribe that has not obtained TAS for 
submission of emission inventories.
    States may not report certain other facilities when EPA issues a 
Federal permit, even though the facility is located within the 
geographic scope of a State's implementation planning authority. When 
the State has developed its emissions inventory collection program 
based on only those facilities for which the State issues operating 
permits, the State or local agency might assume that it is not 
obligated to report the emissions because it has not permitted the 
source.
    The primary challenge with collecting data from such sources under 
the current AERR is that reporting is only provided from States. The 
reported emissions data are, therefore, somewhat limited to what States 
collect and report. In the case of facilities that are located on lands 
outside the geographic scope of a State's implementation planning 
authority and are rightly not reported by a State, the current AERR 
structure does not provide a mechanism for collecting that data.
    For facilities that have EPA-issued, rather than state-issued, 
operating permits, the EPA has evaluated the current AERR to determine 
if States are correct when they do not report emissions data for these 
facilities. The existing version of this subpart says at 40 CFR 
51.15(b) that ``[e]missions should be reported from the following 
sources in all parts of the State, excluding sources located within 
Indian country.'' This language suggests that there is no exemption for 
sources where the State does not issue an operating permit. 
Additionally, 40 CFR 51.25 reads ``[b]ecause of the regional nature of 
these pollutants, your State's inventory must be statewide, regardless 
of any area's attainment status.'' Further review of the current AERR 
finds no exemptions for facilities that are not permitted by the State. 
As a result, the EPA does not need to propose any additional 
requirements in this action for States reporting CAPs. However, to 
ensure clarity with regards to the existing requirements, the EPA 
proposes to add the clarification to Sec.  51.1(c)(1) of this subpart 
that ``a lack of state permitting for point sources or pollutants 
associated with them does not exempt a facility or pollutant from being 
reported by the State.''
    In the case of sources missing from the inventory because the 
facility is located outside the geographic scope of a State's 
implementation planning authority, the owner/operator reporting 
approach of this proposed action, described in section IV.A.5 of this 
preamble, already provides for reporting HAP and incidental CAPs 
directly from owners/operators of those facilities. This requirement 
has not been previously included in the AERR. To resolve the problem of 
missing sources from the NEI, the only additional requirement needed in 
this proposed action would be to require owners/operators to report CAP 
emissions to the EPA for facilities that meet the CAP reporting 
thresholds in Table 1A to Appendix A of this subpart, and that are 
within Indian country where not already reported by a tribe or State.
    The EPA is also considering those owners/operators of certain 
sources located within an Indian Reservation in Idaho, Oregon, and 
Washington who must register and report certain emissions data to EPA 
Region 10 under 40 CFR 49.138. This regulation is part of a set of 
regulations that have been incorporated into Federal implementation 
plans for 39 Indian reservations for those three States. The set of 
regulations is known as the Federal Air Rules for Reservations (FARR) 
in Idaho, Oregon, and Washington. The EPA has proposed revisions to the 
FARR on October 12, 2022 (87 FR 61870), and the EPA has also considered 
these proposed changes in relation to the proposed requirements of the 
AERR. The current requirements specify at Sec.  49.138(b) that it 
applies to ``any person who owns or operates a part 71 source or an air 
pollutant source that is subject to a standard established under 
section 111 or section 112 of the Federal Clean Air Act.'' The rule 
also applies to other owners/operators of air pollutant sources 
including sources that have a PTE of 2 tpy or more of any air 
pollutant, except for sources meeting criteria for a significant list 
of exemptions.
    Under the current and proposed FARR registration rule, the owners/
operators subject to the requirements of Sec.  49.138 must register 
their air pollution source with the Regional Administrator of EPA 
Region 10 (initially and annually) with specific requirements for 
information to be included in such registration. The provision for 
registration includes reporting of information to the Regional 
Administrator that is very similar to the facility inventory and annual 
emissions reports included in this proposal. Emissions reporting under 
Sec.  49.138 is limited to Particulate matter, PM10, 
PM2.5, SOX, NOX, CO, VOC, Pb, 
NH3, fluorides (gaseous and particulate), sulfuric acid mist 
(H2SO4), hydrogen sulfide (H2S), total 
reduced sulfur (TRS),

[[Page 54150]]

and reduced sulfur compounds, including all calculation for the 
emissions estimates. The requirements include specific provisions, 
similar to section IV.A.6 of this preamble, that specify the priority 
of which emissions estimation approaches should be used. This existing 
rule requires additional activities, the specifics of which are not 
critical to this preamble. While the current rule does not include any 
specific electronic submission or formatting requirements, for the past 
7 years sources have been voluntarily submitting their registration and 
emissions reports through an electronic reporting system called the 
FARR Online Reporting System (FORS). The revisions proposed to 40 CFR 
49.138 included requiring electronic reporting via FORS.
    In comparison to the requirements of this proposal, 40 CFR 49.138 
impacts the same major sources within the affected Indian country. In 
addition, 40 CFR 49.138 would impact some of the same non-major sources 
covered by this proposal because the 2-ton PTE reporting threshold in 
that rule is much lower than the major source PTE thresholds for CAPs 
and actual emissions thresholds for HAP in this proposal. Without 
creating a limited exception within this proposal, those sources would 
have duplicative requirements since many of the pollutants required in 
that rule overlap with pollutants the EPA is considering requiring 
under this subpart. Lastly, there are differences in the pollutants 
being reported between 40 CFR 49.138 and this proposal because (1) this 
proposal does not include reporting of emissions of fluorides, 
H2SO4, H2S, TRS, or reduced sulfur 
compounds, and (2) this proposal includes many more HAP than are 
required under that rule.
    As a result of these considerations, this action proposes to 
require owners/operators of facilities located within Indian country 
and not being reported by a tribe or State to report all CAPs directly 
to EPA when the PTE or actual emissions of one or more such pollutant 
exceeds the reporting thresholds in Table 1A to Appendix A of this 
subpart. This requirement is complementary to the previously described 
HAP reporting requirements. For facilities meeting the CAP PTE 
thresholds, owners/operators would need to report all CAP pollutants 
and the incidental CAP requirement would not be relevant to those 
facilities.
    To avoid unnecessary burden for owners/operators of facilities for 
which emissions data must be reported to the EPA under 40 CFR 49.138 as 
described above, the EPA also proposes that certain owners/operators 
would be exempt from the requirements of this subpart for reporting 
emissions of any pollutants already being reported under 40 CFR 49.138. 
The EPA additionally proposes that owners/operators in that situation 
may, at their option, report such exempt pollutants to the EPA 
electronic reporting system along with any information that is required 
to be reported under this subpart. The limited exemption to the AERR 
requirements would only apply to data that are already being reported 
to the EPA under 40 CFR 49.138 for facilities on Indian reservations in 
Idaho, Oregon, and Washington. If a facility is subject to requirements 
in the AERR and 40 CFR 49.138, then the owner/operator of that facility 
would still be required to report under the AERR for those data that 
are not reported under 40 CFR 49.138.
    While the proposed approach avoids some duplication of burden, the 
EPA recognizes a different approach could further reduce duplicative 
reporting. The EPA intends to adapt CAERS so that it would allow 
emissions reporting to the EPA through CAERS to meet the compliance 
requirements of 40 CFR 49.138. To do this, the EPA would ensure that 
all elements of 40 CFR 49.138 would be met as part of electronic 
reporting via CAERS. Once EPA develops and provides a CAERS compliance 
approach for owners/operators to meet reporting requirements of 40 CFR 
49.138, EPA expects that CAERS would replace the current FORS data 
collection system.
2. Facilities Within Federal Waters
    Under the current AERR, States are not obligated to report 
emissions from offshore facilities operating in Federal waters because 
States generally do not have jurisdiction over such sources. The EPA 
has jurisdiction over certain air emissions activities within Federal 
waters, including OCS sources subject to regulation under CAA section 
328. To address this gap in emissions data, the EPA is proposing 
provisions to address: (1) which owners/operators of facilities in 
Federal waters would need to report, (2) what data would need to be 
reported, and (3) how that data should be reported. The EPA is 
requesting comment on whether these reporting requirements would be 
duplicative.
    First, regarding which owners/operators operating in Federal waters 
would report under this proposed action, the EPA is aware that many 
facilities already report emissions data to the Bureau of Ocean Energy 
Management (BOEM), which in turn reports these data to EPA. To avoid 
such facilities being subject to AERR requirements, the EPA proposes at 
Sec.  51.1(a)(2) that owners/operators would be required to report for 
facilities that operate within Federal waters, including (1) deepwater 
ports subject to CAA requirements under the Deepwater Port Act, and (2) 
OCS sources as defined in CAA section 328(a), with the exception of: 
owners/operators of facilities that are regulated under 43 U.S.C. 1331 
et seq. (the Outer Continental Shelf Lands Act) and that are located 
(a) offshore of the North Slope Borough of the State of Alaska, or (b) 
offshore of the United States Gulf Coast westward of longitude 87 
degrees and 30 minutes (i.e., offshore Texas, Louisiana, Mississippi, 
and Alabama).
    Second, the EPA is considering which data would need to be reported 
by owners/operators of these facilities. Many OCS sources and other 
facilities in Federal waters are subject to the requirements of Federal 
or State title V operating permit programs that contain emissions 
reporting requirements and, in some cases, require permittees to 
annually quantify actual emissions for purposes of calculating permit 
fees. For those facilities subject to title V emissions reporting and/
or emissions quantification requirements, the EPA proposes that owners/
operators should use the same approaches to identify the emissions 
sources of such facilities and to estimate and submit emissions data 
under this subpart. Emissions sources at such facilities may include 
portable sources (e.g., drill rigs), operation of units that, if on 
land, would be stationary sources (e.g., boilers, control devices, 
chemical processing equipment, refrigeration units), and marine vessels 
(e.g., engines that power the movement of service vessels within 25 
miles of an OCS source, and marine vessel engines used for other 
purposes when stationary).
    In addition, the EPA proposes to require owners/operators of 
facilities in Federal waters (as described above) to report all CAPs 
when the PTE or actual emissions of one or more such pollutant exceeds 
the reporting thresholds in Table 1A to Appendix A of this subpart. 
This requirement is complementary to the previously described HAP 
reporting requirements. For facilities meeting the CAP thresholds, 
owners/operators would need to report all CAP pollutants and the 
incidental CAP requirement would not be relevant to those facilities.
    Third, the EPA is assessing how these owners/operators should 
report emissions data. In addition to meeting the other point source 
reporting requirements under this subpart, the EPA proposes a 
requirement for facilities operating in Federal waters to report 
emissions using the Federal

[[Page 54151]]

waters region codes provided in the EPA electronic reporting system. 
Because these Federal water regions are extremely large, the EPA 
expects that most facilities will only operate within a single area, 
but when portable facilities operate in multiple areas of Federal 
waters, owners/operators would need to report those emissions 
separately with different Federal waters region codes.
    Lastly, to support this proposed approach, the EPA further proposes 
the definition of Federal waters to mean those waters over the ``Outer 
Continental Shelf'' as defined in the Outer Continental Shelf Lands Act 
(43 U.S.C. 1331(a)).
    The EPA also recognizes the possibility of duplicative reporting 
related to any reporting that may be required by permits and/or for 
assessing title V permit fees. To help avoid duplicative burden, the 
EPA urges commenters to describe any duplicative burden that this 
proposal may cause for emissions reporting.

C. Source Test Reporting

    To improve the data available to the EPA, States, and sources to 
estimate emissions, the EPA proposes to require electronic source test 
reporting (as first explained in section III.A.3 of this preamble) from 
point sources for certain source tests. This action would require such 
reporting for source tests already required to be performed, to help 
improve emissions factors. An emissions factor is a key tool used in 
the creation of emissions inventories, for example, to estimate air 
pollutant emissions from a normally operating, point-source process or 
activity (e.g., fuel combustion, chemical production). An emissions 
factor relates the quantity of pollutants released to the atmosphere 
from a process to a specific activity associated with generating those 
emissions. For most application purposes, emissions factors are 
intended to represent the average emissions for all emitting processes 
of similar design and characteristics (i.e., the emissions factor 
represents a population average). As such, emissions factors provide an 
emission rate that may be appropriate for use by owners/operators of 
facilities when site-specific source measurements of an emission 
process are not available. While greater uncertainty is associated with 
use of emissions factors as compared to site-specific source 
measurements, it is nevertheless important to ensure that emissions 
factors are high quality.
    EPA's most recent approach to develop emissions factors has been 
prepared in response to a review of EPA's emissions factors program by 
the National Academy of Sciences and EPA's Office of Inspector General. 
In 2006, that review resulted in the Inspector General report 
previously referenced in section IV.A.3 of this preamble. As described 
in EPA's most recent documentation on emissions factor calculation 
procedures,\41\ the EPA revised its emissions factor calculation 
approach in response to that report. The EPA's emissions factor 
procedures rely on direct measurement of releases from point source 
processes or activities (i.e., a sample of the process emissions is 
collected and analyzed). Hereafter, such measured emissions data from a 
source will be referred to as ``source test data.'' EPA's progress on 
improving emissions factors is limited to the available source test 
data received by the Agency.
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    \41\ Recommended Procedures for Development of Emissions Factors 
and Use of the WebFIRE Database, U.S. EPA, EPA-453/B-21-001, 
November 2021, https://www.epa.gov/air-emissions-factors-and-quantification/procedures-development-emissions-factors-stationary.
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    As previously described in section IV.A.4 of this preamble, this 
action proposes to require emissions reporting of annual total HAP from 
owners/operators. The benefit of this HAP emission collection program, 
however, depends on the quality of the annual emissions data reported 
by owners/operators of facilities. The quality of the annual emissions 
totals depends in part on the availability and quality of the emissions 
factors, which in turn depend on the availability and quality of HAP 
emissions source test data.
    While the Inspector General report highlighted the lower-than-
desired quality of published emissions factors, the EPA has thus far 
been unable to revise many of these factors and continues to be limited 
in part by the lack of source test data. This limitation remains 
despite EPA's efforts to revise its regulatory framework of stationary 
source emissions reporting to include electronic source test data 
reporting as a component of industry-specific regulations included in 
40 CFR parts 60, 61, 63, etc.\42\ The pace of progress on improving 
these factors to date has been limited in part by the gradual nature of 
adding industries and pollutants one regulation at a time. In addition, 
since those regulations address specific pollutants and, in some cases, 
allow for reporting of emissions of one pollutant (such as filterable 
PM2.5) to serve as a surrogate for other pollutants (such as 
specific HAP metals), sources do not always conduct tests for, and the 
EPA does not receive data for, non-surrogate pollutants.
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    \42\ A complete list of regulations that require reporting to 
CEDRI is available on EPA's website at https://www.epa.gov/electronic-reporting-air-emissions/cedri#list.
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    In addition to the recommendations of the Inspector General Report, 
States have long expressed their concerns with the many missing 
emissions factors in addition to the low-quality emissions factors 
included in EPA's AP-42 and WebFIRE emissions factor compilations. 
These State concerns have been compiled and included in the docket for 
this proposed action. Despite these concerns, these emissions factor 
compilations largely remain a foundational piece of emissions 
inventories. The States and the CAERS application use AP-42 and WebFIRE 
emissions factor data to support owners/operators of facilities by 
providing the emissions factors directly within the emissions 
calculation tools used during emissions reporting. While owners/
operators are expected to use site-specific source test data to 
calculate and report emissions when available and appropriate for that 
use, the emissions factors are often the only emission rate information 
available. Thus, improving the quality of the emissions factors is 
central to improving emission inventory quality overall.
    With this proposed action, the EPA is seeking to improve emissions 
factors to support improved emissions inventories via the proposed 
collection of additional source test data. The EPA has recently 
completed the updates to the WebFIRE system that automates most of the 
emissions factor development processes described by the emissions 
factor procedures document previously mentioned. As a result of these 
efforts, the EPA issued its first set of revised emissions factors for 
public review in November 2021.\43\ Now that the development procedure 
infrastructure is largely completed, the EPA finds that increasing the 
amount of source test data by obtaining information from the thousands 
of emissions processes and hundreds of pollutants included for 
stationary sources in the NEI is a logical progression in emissions 
factor improvement. By improving emission factors, emissions estimates 
are improved as well, supporting the needs for high quality data to 
support EPA's regulatory and non-regulatory activities as described in 
section IV.A of this preamble.
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    \43\ See https://www.epa.gov/air-emissions-factors-and-quantification/documentation-supporting-draft-and-final-emissions-factors.
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    To assess the feasibility of further collection of source test data 
and gathering information to design the proposed approach, the EPA is

[[Page 54152]]

considering (1) whether source test data are readily available or could 
be readily available, (2) how such data could be collected 
electronically and efficiently, (3) which existing data would be of 
interest to the agency, and (4) how to phase in any new reporting 
requirements.
    The EPA is aware that direct measurements of facility or process 
emissions are conducted for a variety of reasons, including 
characterizing process emissions and/or control device performance, 
assessing changes in process or control device operation on emissions, 
and demonstrating compliance with Federal, State, local, or tribal air 
regulations. Emissions testing may also be conducted as part of 
performance evaluations such as relative accuracy test audits (RATAs). 
Performance evaluations include linearity checks (which measure an 
instrument's ability to provide consistent sensitivity throughout its 
operating range) and routine calibrations of continuous emissions 
monitoring system (CEMS) equipment, which provide emissions data much 
more frequently than testing. Emissions data from CEMS are mostly used 
for compliance purposes but can also be used for emissions factor 
development. The reasons why such testing and evaluation occurs 
includes both the CAP and HAP aspects of air quality planning and 
implementation. Thus, these activities are conducted for a larger range 
of pollutants than would be available from reporting required by 
regulations under 40 CFR parts 60, 61, and 63, including those that 
have been updated for electronic reporting and those that continue to 
require testing and reporting by other means. Based on this 
information, it appears to the EPA that additional unreported test data 
are readily available.
    To aid owners/operators in planning and reporting the results of 
emissions tests, the EPA developed the Electronic Reporting Tool (ERT), 
and CEDRI. Further, the EPA has required their use in the revised 
regulations previously described. The ERT is used by companies that 
perform emissions testing for industrial sources and has been in use 
for over 10 years. As the EPA has promulgated regulations to require 
electronic reporting with the ERT, it has modified the ERT and CEDRI to 
make sure that they support the source measurement methods required by 
those regulations. As a result, the EPA has been collecting source test 
data for selected pollutants from facilities regulated by those revised 
rules for many years. The ERT and CEDRI collection infrastructure, in 
addition to the recently implemented WebFIRE emissions factor 
calculation procedures, will help ensure an efficient approach for data 
collection and emissions factor development.
    Information collected by the EPA from the companies that perform 
source measurements for industrial sources supports the idea that 
electronic reporting for all pollutants via the ERT is commonly 
supported by these companies. The EPA understands that it would be rare 
to find any of these companies unfamiliar with the reporting via the 
ERT. Some of our experience suggests that companies may find it more 
difficult and more costly to prepare and submit reports in hard copy 
(i.e., paper test reports) rather than reporting electronically, since 
much of the data collection process has been made electronic.
    The EPA also is considering whether source test data should be 
reported to the EPA directly by owners/operators or via the States. 
States currently collect some test data as part of their implementation 
of source permits and compliance, for example, when States require such 
tests for their own reviews of emissions from stationary sources. Given 
this current reporting, it is reasonable to expect that some States may 
want to provide source test data to EPA. Such an approach might 
parallel reporting that is currently done for CAP emissions and can be 
done for HAP emissions. Including States in such reporting could have 
the advantage of potentially meeting the needs of those States that 
wish to be intermediaries or review the facility source test prior to 
it being reported to the EPA for use in emissions factors.
    The possible disadvantage of States reporting the source test data 
could be the added complexity that such an approach may cause. With the 
existing CEDRI approach currently in place, States have a period during 
which they may optionally review the source test results and advise the 
EPA regarding the validity of the source test and any data quality 
concerns that the State may have. In addition, when current EPA 
regulations require source tests, they require that data to be reported 
directly from owners/operators of stationary sources. Any difference 
that might be proposed from that current approach could have a further 
disadvantage of causing inconsistencies for owners/operators in how to 
report source test data. Specifically, reporting under such an approach 
could depend on whether the requirement to report for a pollutant and 
process was under any finalized version of this proposed action or 
under one of the other subparts of 40 CFR that require such reporting. 
As a result of these significant disadvantages, the EPA expects that 
any proposed action would be most efficiently and effectively 
implemented through direct reporting of source test data to the EPA 
from owners/operators and continuing to allow for State review and 
comment.
    The EPA has additionally reviewed the requirements of the ERT to 
ensure that the data collected with the ERT would be sufficient for the 
purpose of generating emissions factors. To be able to use the source 
test data for purposes of emissions factors, the EPA has identified 
four additional types of information that are necessary to provide a 
complete characterization of a unit's emissions in relation to its 
operation. These are (1) the capacity of the unit being tested, (2) the 
load of the unit during the testing period, (3) the level of activity 
of the unit and operating conditions of the unit during the testing 
period, and (4) process data (e.g., temperatures, flow rates) 
pertaining to the unit and its control devices during the testing 
period. All four of these are key components to ensuring emissions 
factors appropriately represent unit operation. For example, 
NOX emission rates from a unit operating at 50 percent load 
using natural gas with 50 gallons per hour of ammonia injection differ 
from a unit operating at 95 percent load using fuel oil with 75 gallons 
per hour of ammonia injection. As a result, correctly computed 
emissions factors from these separate modes could differ as well. 
Without the full information, the EPA may not be able to discern the 
differences in unit operation and incorrectly combine source test data, 
which could lead to emissions factors erroneously assigned to certain 
combinations of units, processes, and controls.
    As a result of these considerations, the EPA proposes to require 
owners/operators of point sources to report performance test results 
and performance evaluations that meet the following conditions: (1) 
data would only be reported (under this proposed rulemaking) when they 
are not otherwise reported to the EPA based on regulations listed at 
https://www.epa.gov/electronic-reporting-air-emissions/cedri#list; (2) 
the data are gathered to meet any other EPA or State requirement; (3) 
the data are supported for reporting by CEDRI or an analogous 
electronic reporting system; and (4) the results were not from a 
project, method, device, or installation (or any component thereof) 
that was produced, developed, installed, and used only for research 
purposes. This final criterion

[[Page 54153]]

was added to avoid any potential conflict between the definition of 
confidential data and the treatment of ``emission data'' in accordance 
with 40 CFR 2.301. More information on the issue of confidential data 
for this proposed action is available in section IV.H of this preamble.
    The EPA is seeking comment on these criteria. Specifically, the EPA 
would be interested in knowing of examples of tests that meet these 
criteria, but which do not meet the EPA's objective as described in 
this section to support emissions factors. If such examples exist, the 
EPA is further interested in suggestions of how to revise, or 
supplement, the criteria to avoid collecting such information that does 
not meet the objective of this section.
    Additional aspects of EPA's proposed approach to collect source 
test data include the following. The proposed reporting, if finalized, 
would be limited to include source tests and performance evaluations 
beginning on the effective date provided in the final rulemaking. It 
would require submission of data via CEDRI, including the four types of 
information as previously noted: (1) capacity of the unit being tested, 
(2) the load of the unit, in terms of percent capacity, during the 
testing period, (3) the level of activity of the unit during the 
testing period (e.g., input consumption rate, product consumption, heat 
input, and/or output production rate), (4) operating conditions of the 
unit during the testing period, and (4) process data such as 
temperatures, flow rates, pressure differentials, pertaining to the 
unit and its control devices during the testing period. The ERT would 
need to be used when it supports the source test or performance 
evaluation and, in other cases, a spreadsheet-based approach could be 
required. Finally, each report would need to be submitted by the 
scheduled date required by the State or Federal action motivating the 
test. When no such date exists, the report would be required within 60 
days of completing the source test or performance evaluation.

D. Reporting for Certain Small Generating Units

    With this proposed rulemaking, the EPA seeks to solve long-standing 
challenges associated with emissions from certain types of intermittent 
combustion sources. Interest in emissions and ozone formation on high 
energy demand days (HEDDs) has led the EPA to consider collecting 
information from sources that operate to offset electricity demand from 
the electricity grid during these times. The EPA already collects 
detailed data from EGUs through the Clean Air Markets Program, which 
requires reporting of hourly data from CEMS as specified by 40 CFR part 
75. In addition to these sources, other electricity units including 
small generating units (less than 25 MW or otherwise not subject to 
reporting under 40 CFR part 75 or the mercury air toxics NESHAP at 
Subpart UUUUU of 40 CFR part 63) and backup generators (BUGs) are run 
periodically both to offset grid-based energy needs at energy intensive 
facilities and to generate electricity for the grid. These sources may 
contribute significantly to tropospheric ozone on high-temperature days 
in some areas, leading to public health concerns. As climate change is 
expected to result in warmer summers, the use of this distributed 
generation could increase. While such data are important to better 
understand the environmental impacts of these sources, the EPA is not 
currently collecting such data from States or owners/operators.
    Without data collection, EPA's understanding of these sources is 
limited. First, the EPA lacks important details about intermittent 
activity of these sources. For understanding ozone impacts, the EPA and 
States have a compelling need to know when emissions occur on a finer 
temporal resolution than typical annual emissions (i.e., which days). 
Without such information, past studies \44\ have shown that efforts to 
model HEDDs fail to fully characterize ozone formation on such days.
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    \44\ Northeast States for Coordinated Air Use Management, High 
Electric Demand Day and Air Quality in the Northeast, 2006. https://www.nescaum.org/documents/high-electric-demand-day-and-air-quality-in-the-northeast/final-white-paper-hi-electric-demand-day-06052006.pdf. Ozone Transport Commission, Stationary and Area Source 
Committee, HEDD Workgroup, White Paper: Examining the Air Quality 
Effects of Small EGUs, Behind the Meter Generators, and Peaking 
Units during High Electric Demand Days 2016. https://otcair.org/upload/Documents/Reports/HEDD_Workgroup_White_Paper_Final_2016-11-10.pdf. Ozone Transport Commission, Stationary and Area Sources 
Committee, Strategies to Reduce Emissions of Nitrogen Oxides on High 
Electric Demand Days, 2017. https://otcair.org/upload/Documents/Meeting%20Materials/OTC_HEDD_Workgroup_Strategies_Whitepaper_Final_Draft_08282017.docx.
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    Second, the EPA has reason to question the emission rates that 
would be appropriate for estimating emissions from such sources. 
Existing emission rates (i.e., emissions factors) for all units of any 
type are based on emission source testing methods that are correctly 
used during steady State operation of the emission unit to achieve 
valid emission tests. By contrast, the operation of these intermittent 
sources means that they are frequently turned on and off, which has an 
unknown impact on the resulting emissions. As an illustration of the 
issue, it is common knowledge that engines run more efficiently (thus 
more cleanly) once they have warmed up. To the extent that units run 
periodically spend more time in an inefficient State of operation, they 
would be expected to have higher emissions rates. However, the impact 
of such operation is not well understood, and the EPA is not aware that 
it has been quantified.
    Over the past two decades, States and multi-jurisdictional 
organizations have discussed with the EPA the possible importance of 
intermittent sources on air quality. While some proposals have been put 
forward to reduce the problem of emissions from these types of 
intermittent units, the full understanding of the problem has been 
limited based on lack of available data.
    In a 2017 publication, researchers from the University of 
Wisconsin-Madison linked peak electricity demand to high levels of air 
pollution.\45\ Using data collected from 27 States between 2003 and 
2014, the researchers showed that the electricity used to power air 
conditioners increased emissions of SO2, nitrogen oxides, 
and carbon dioxide (CO2) by an average of almost four 
percent for each pollutant per degree Celsius increase, above a certain 
reporting threshold.
---------------------------------------------------------------------------

    \45\ Abel et al., Response of Power Plant Emissions to Ambient 
Temperature in the Eastern United States, Environ. Sci. Technol., 
50, 10, 5838-5846, 2017. See also https://www.acs.org/content/acs/en/pressroom/newsreleases/2017/may/keeping-cool-in-the-summer-leads-to-increased-air-pollution.html.
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    While they have received more attention in recent years, emissions 
from these small generating units have been historically challenging to 
track, a fact that has contributed to EPA's aim to understand and 
improve the data in this sector. The EPA recognizes that emissions from 
small generating units may increase as extreme weather and temperature 
events are likely to become more frequent.\46\ Alongside this potential 
rise in emissions are increases in public health risks from 
tropospheric ozone formation, as well as nitrogen oxides and PM 
emissions.
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    \46\ U.S. Global Change Research Program, Fourth National 
Climate Assessment, Volume II, Impacts, Risks, and Adaptation in the 
United States, Chapter 4: Energy Supply, Delivery, and Demand, 2018. 
https://nca2018.globalchange.gov/.
---------------------------------------------------------------------------

    As a result of past investigations, some States have explored how 
they can gather information about intermittent sources. For example, 
the Maryland Department of Environmental Quality (MDEQ) requires that 
Curtailment Service Providers (CSPs) provide data to the State under 
COMAR 26.11.36.04.

[[Page 54154]]

CSPs are entities that administer electricity demand response programs 
by working with companies that use and generate electricity to decrease 
electricity demand by deploying capacity from smaller units like BUGs 
that can reduce demand from the electricity grid. The Maryland 
regulation requires CSPs to report information about the units they 
administer, including unit capacity, manufacturer, and model as well as 
the types of fuel used and information about the days and hours of 
operation. It also sets an exclusionary threshold based on output. It 
excludes emergency stationary engines with an output less than 500 
horsepower (hp) and excludes non-emergency stationary engines with an 
output less than 500 hp that serve as a primary source of power for 
agricultural equipment or industrial equipment. While this information 
only partially addresses the needs for the State, discussions with MDEQ 
identified that the information collected has helped the State 
understand the scope of the intermittent unit emissions. This example 
provides some evidence that partial data collection can inform the 
larger temporal patterns in emissions associated with intermittent 
sources.
    The EPA is also aware that federally enforceable regulations can 
limit the ability of source operators to deploy older or more polluting 
engines. Examples of such regulations include the NESHAP for 
Reciprocating Internal Combustion Engines (RICE) in 40 CFR part 63, 
subpart ZZZZ; the New Source Performance Standard (NSPS) for Stationary 
Compression Engines in 40 CFR part 60, subpart IIII; and the NSPS for 
Stationary Spark Ignition Engines in 40 CFR part 60, subpart JJJJ. 
These rules define allowable emission rates and, as a result, limit the 
types of sources that can be deployed. These rules do not restrict use 
of units that meet the emissions standards, which can be deployed for 
electricity generation during HEDD periods, and these rules do not 
collect information that would help understand the impact of such 
sources.
    The EPA also is considering the uncertainty associated with 
emissions rates from units that are operated intermittently, as 
previously described. This consideration is important because it 
impacts whether the EPA would require reporting of emissions values 
and/or other emissions data such as fuel use and unit types. If 
emission values (i.e., mass of pollutants) were provided alone, then 
whatever emissions rates were selected by data reporters would be the 
basis for the emissions. In this case, the EPA would not be able to 
adjust the emissions based on any improved emissions rate data that may 
become available. Additionally, with emissions values alone, the EPA 
would not be able to explore the impact of different emissions rates on 
the ability of the data to better predict modeled air quality. Thus, 
based on the limitations that would be imposed, the EPA is proposing to 
collect information on fuel use or heat input and unit types.
    The EPA is considering all the factors described above and has 
weighed the importance and long-standing need for the data to 
understand ozone formation in some areas, the uncertainty associated 
with emissions rates, and the potential burden of the various options 
available. The EPA is considering the potential burden that could be 
caused by requiring emissions or activity data reporting from States 
from small generating units used to reduce electricity demand or meet 
that demand during peak energy needs. Any requirements imposed on 
States by this proposed action could in turn be imposed by States on 
their sources for collection by the State and subsequent reporting to 
EPA. The EPA also recognizes the great deal of uncertainty about units 
associated with HEDDs and has included in this preamble one proposed 
approach, one additional option, and 2 additional alternatives that the 
agency is considering.
    Based on these considerations, the EPA is proposing requirements 
for some States and certain owners/operators. First, the EPA proposes 
that States would report facility inventory information (e.g., unit 
characteristics) and daily fuel use or heat input data for units that 
operate during the year at point sources (as defined by this proposed 
action) and that meet specific criteria. Those criteria are (a) the 
hourly or daily emissions and activity data from the unit are not 
otherwise reported to the EPA, (b) the unit was operated to offset 
electricity demand from the electricity grid, and (c) the unit is 
located at a facility that operates on land. This approach is intended 
to collect data for the appropriate units and avoid duplication with 
any reporting done as part of other EPA requirements. By limiting 
reporting to those small generating units for which hourly or daily 
heat input data are not otherwise reported, EPA would ensure that data 
reported to the EPA to comply with 40 CFR part 75 or other regulations 
would not need to be re-reported under the AERR.
    Second, the EPA proposes to require owners/operators of facilities 
located outside the geographic scope of States' implementation planning 
authority to report for units at point sources that meet the same 
criteria as the units that would be reported by States. For the 
purposes of this preamble, the units covered by the proposed 
requirement just described will be referenced as ``small generating 
units''.
    Third, the EPA proposes a definition of small generating units to 
mean ``any boiler, turbine, internal combustion engine or other unit 
that combusts fuel on an occasional basis to generate electricity for 
the electricity grid or for on-site use by a facility other than for 
emergency use.'' Because the proposed reporting requirement would not 
cover any units already reporting to the EPA and would cover units only 
at point sources that are already being reported to EPA, the EPA does 
not believe that the definition needs to specifically identify by size 
which units are ``small,'' since larger units are presumably reporting 
because of their size based on other regulations.
    The data elements that the EPA proposes would be reported include 
identification of each small EGU used to offset electricity demand from 
the electricity grid for a given year; the unit's rated capacity in hp 
and kilowatts; the unit's manufacturer and model; the installation date 
of the unit; source classification code (including the fuel type); and 
for each day of operation: the emissions reporting period, reporting 
period type as daily, date of activity, fuel used or heat input and 
associated units of measure, and optionally the start hour and end hour 
of operation. These small generating units would need to be reported to 
reflect the data fields included in proposed Table 2A to Appendix A of 
Subpart A and Table 2C to Appendix A of Subpart A. Finally, the EPA 
proposes that this reporting would start with the 2026 inventory year 
and that the deadline for such reporting would be one year and 15 days 
after the year after the inventory year (e.g., the deadline for 
reporting 2026 emissions would be January 15, 2028).
    Under these proposed requirements, States would have the 
flexibility to either collect the data from the CSPs (where such 
entities exist) or from the owners/operators of facilities that operate 
small generating units. This implementation could include other 
entities, such as large energy companies, that also have agreements 
with other companies to deploy small generating units periodically 
under certain circumstances. The EPA expects that collecting that data 
from the CSPs or other types of companies with demand reduction 
agreements would provide the lowest burden option for States.

[[Page 54155]]

Additionally, the EPA expects that the CSPs and other companies 
aggregating demand side reductions could be in the best position to 
gather from the owners/operators of small generating units the data 
that needs to be reported as part of their normal operations. This 
design could reduce burden because the number of CSPs and other 
companies with demand reduction agreements within a State could be far 
smaller than the number of facilities with small generating units that 
operate in any particular year.
    The proposed requirements would require activity data for small 
generating units in addition to the State's best estimate of annual 
emissions for small generating units that are already required under 
the current AERR and proposed to continue to be included under this 
action. The EPA recognizes the challenges of estimating such emissions 
based on the measurement challenges for startup/shutdown conditions 
noted above regarding emissions factors.
    The EPA is proposing these requirements in part based on the idea 
that by obtaining data from some of the small generating units (i.e., 
those operating at point sources as defined by this proposal), enough 
information could be collected about temporal patterns to allocate 
emissions from the remaining small generating units. Those other 
emissions from small generating units are currently covered in the NEI 
as part of the nonpoint county-total emissions based on overall State 
fuel consumption and available emissions factors. Under the proposed 
requirements, the EPA would collect more limited data from point 
sources as defined and extrapolate that the temporal patterns apply to 
the portion of nonpoint fuel combustion data associated with small 
generating units.
    The proposed requirements have at least two limitations. First, 
since the nonpoint fuel combustion emissions are based on standard 
emissions factors, they may not accurately reflect startup/shutdown 
related emissions from such units. Second, the proposed requirements 
are incomplete because they limit the units required to be included to 
only those units at point sources as defined by the proposed point 
source definition in this action. Many BUGs and other units deployed 
for demand reduction are located at retail establishments that are 
unlikely to be major sources (because of low emissions) and are 
specifically excluded from the definition of non-major sources by the 
NAICS codes the EPA is proposing to be included in this proposal. Not 
having all units would create two challenges: (a) the EPA would need to 
determine with some other data source what portion of the nonpoint fuel 
combustion should be temporally allocated based on the data collected 
because this proportion may vary with each year in relation to 
temperatures and the deployment of units for demand reduction; and (b) 
the incomplete set of units also would not include the spatial detail 
that would otherwise be achieved by having coordinates for all 
individual units operated to meet peak energy needs.
    As part of the proposed requirements described above and to avoid 
the associated limitations, the EPA is co-proposing and requesting 
comment on one option and two alternatives. None of these options 
addresses the limitation of emissions factors during startup and 
shutdown, but they do either collect activity data from more units or 
limit the data collection to reduce burden. The proposed requirements 
described above are referenced below as the ``preferred alternative.''
    The EPA proposes an option to require a one-time collection from 
all small generating units for a single year. The EPA is considering 
including this ``One-time Collection Option'' in addition to the 
preferred alternative and is also considering whether to use the One-
time Collection Option as the sole approach in any final action. To 
accomplish the one-time collection, the EPA would require CSPs and 
other operators or aggregators of small generating units (not States or 
owners/operators of point sources) to report to the EPA the same data 
elements as are described in the preferred option (i.e., the facility 
inventory and daily fuel use or heat input) for either the 2024 or 2025 
inventory year. The EPA would select which year in the final rule. The 
deadline for such reporting would be October 31 the year after the 
inventory year (e.g., for 2024 reporting, October 31, 2025).
    The One-time Collection Option would help the EPA to determine 
whether and how to implement an annual reporting requirement, and it 
could inform the development of some predictive model to avoid a need 
for annual reporting. For example, a one-time study could allow for 
correlation between the one-time data and other routinely available 
data (such as temperature, fuel prices, and electricity prices), such 
that the EPA could use such other data to calculate emissions from 
intermittent generation for subsequent emission inventory years. A one-
time collection could also provide locations of units included in CSPs 
to improve spatial allocation of nonpoint emissions to the model grid 
cells for air quality modeling. In addition to providing more detailed 
data, an advantage of a one-time collection requirement is that it 
would have a lower burden on the CSPs than would an ongoing 
requirement. The disadvantage of a one-time requirement is that a 
correlation may not be found, and thus this rule would need to be 
further revised, delaying the receipt of such information by the EPA 
and States.
    The EPA is also co-proposing and requesting comment on two 
alternative approaches that would replace the preferred alternative. 
With Alternative D2, the EPA proposes to expand the preferred 
alternative to require data from States for all small generating units 
that are not otherwise reported to the EPA rather than only those at 
point sources. Alternative D2 would not expand the point source 
definition in a way that would require reporting of annual emissions. 
Rather, Alternative D2 would require States to report the facility 
inventory information, estimated annual emissions, and daily activity 
data as described under the proposed approach, but only for small 
generating units. Other point source requirements for facilities with 
such units would apply only for those facilities that meet the point 
source definition included in this proposal. For example, a retail 
facility that is excluded because of its primary NAICS code for HAP 
reporting and otherwise does not emit pollutants at levels required to 
be reported as a point source would only need to be included in the 
State report for the small generating units that operated during the 
reporting year. If the EPA finalizes Alternative D2, the same State 
deadlines for point source reporting would apply. Under this 
alternative, no adjustment would be made for owners/operators of 
facilities within Indian country. Alternative D2 has the advantage of 
collecting more detailed data but the disadvantage of higher burden on 
States and the entities from which they collect that data.
    Finally, the EPA is co-proposing and requesting comment on 
Alternative D3, which would reduce burden on States relative to the 
preferred alternative by requiring reporting about small generating 
units from only those States that have ozone non-attainment areas and 
those States linked to downwind non-attainment areas as would be 
identified in whatever transport regulatory action has most recently 
been promulgated by the EPA on January 1st of the emissions year. One 
disadvantage of Alternative D3 is that the EPA does not currently have 
data about whether the small generating units within non-

[[Page 54156]]

attainment areas are the only ones that are important in terms of 
impacting air quality within non-attainment areas, because the EPA does 
not have data on any such units irrespective of their location. In 
general, the EPA is aware that emissions sources outside of non-
attainment areas can contribute to ozone within those areas, and small 
generating units could be a type of source that could contribute. In 
the preferred alternative, emissions data from small generating units 
at all point sources would be collected, and the EPA could use that 
information to determine which small generating units contribute to 
higher ozone concentrations within non-attainment areas. The advantage 
of Alternative D3 is that it would decrease the number of potential 
States required to report from 50 to 23, the number with ozone non-
attainment areas, plus States linked to downwind non-attainment areas. 
Alternative D3 would have the same requirements for the types of units 
and the data fields to report as the preferred alternative but would 
limit the States and owners/operators that would need to report.

E. Provisions for Portable and Offshore Sources

    As previously noted, the EPA intends for the NEI to include a 
complete accounting of point sources that meet the emissions reporting 
thresholds included in this proposed action. The current AERR does not 
clearly address some atypical cases, which include portable facilities 
(e.g., asphalt plants) and offshore sources (e.g., oil rigs, drilling 
engines on barges, windfarm installation vessels) within State waters. 
This action seeks to address both the definition of a portable facility 
and to ensure that such sources are reported to the NEI.
    While portable facilities can move, they are not necessarily 
considered with the nonpoint or nonroad mobile source portion of the 
NEI. Under the current AERR, when these portable facilities meet the 
point source reporting threshold, States can report them as point 
sources without specific location information. In reporting portable 
facilities, States use a placeholder county code of ``777'' to indicate 
that those sources move around a State throughout the year. In this 
way, no location coordinates are then required for reports of portable 
facilities. The problem with the current approach is that the location 
of emissions is not available for modeling the air quality impacts of 
the source. If a portable source remains in a single location for a 
long enough period, then it could conceivably have impacts on local air 
quality and States. The EPA, States, and the public may, therefore, 
benefit from location information to properly account for the facility.
    Some States are currently reporting atypical sources to the NEI, 
but it is not clear that all such sources are being reported from all 
States. Some of these facilities have emissions that exceed the point 
source PTE CAP reporting thresholds, and with new HAP reporting 
thresholds that may be adopted based on this proposed action, 
additional portable facilities may need to be reported. A robust 
offshore source inventory of drill rigs is available for facilities 
operating in Federal waters under the jurisdiction of the Bureau of 
Ocean Energy Management, and the EPA is proposing in section IV.A.B of 
this preamble to collect data from facilities operating in Federal 
waters under EPA jurisdiction. These facilities, however, do not 
include facilities operating in State waters (e.g., oil platforms, 
drilling engines on barges, construction activities, wind turbines). 
Emissions from these sources should be reported by States as point 
sources when such sources exceed the point source reporting thresholds. 
Finally, reporting emissions for portable facilities requires a 
specific treatment of county codes and location information, and the 
requirements for that type of reporting are not explained in the 
current AERR requirements.
    Based on these considerations, the EPA proposes to clarify that 
both portable facilities and offshore facilities within State waters 
should be considered when States determine which sources should be 
reported to meet point source requirements of this proposed action. The 
EPA also proposes to add a definition of portable facility to mean ``a 
facility that does not have a fixed location such as an asphalt plant 
or portable land or sea-based drilling rig.'' In addition, this action 
proposes to include an explanation to use county code ``777'' to 
reflect the lack of county specificity when such sources are moved 
among counties over time. Facilities reported in this manner would 
still need to be reported for their emissions within a State. This 
proposal also includes an exception for the requirement of submitting 
facility air centroid coordinates or for release point coordinates for 
portable facilities.
    The design of this proposed action leaves open the possibility that 
the owner/operator of a portable facility may need to report emissions 
when the annual emissions of the facility exceed any of the emission 
reporting thresholds used to define point sources. Two special cases 
for reporting could arise from these scenarios. All cases that 
reference operations within States and Indian country include 
operations within any waters associated with those areas (e.g., State 
waters).
    First, the EPA proposes that portable facilities operating solely 
within Indian country where a tribe or State does not report CAP or HAP 
emissions data would be required to report emissions and to designate 
the tribe in which it operated using the EIS Tribal Code provided by 
EPA. In this case, owners/operators of a portable source would follow 
the same reporting requirements as for stationary facilities. For 
example, this proposed requirement would mean that owners/operators of 
portable sources would report CAP and HAP directly to EPA when neither 
a tribe nor a State reports that emissions data.
    Second, the EPA proposes a requirement that portable facilities 
operating across State and/or Indian country boundaries would report 
directly to the EPA any emissions not reported by those States and/or 
tribes. Relevant CAP or HAP emissions would need to be reported by 
State and/or by tribe per other requirements of the rule. The EPA 
proposes that owners/operators could optionally include the specific 
time periods during which they operated in each region with their 
emissions reports. This case includes both tribes that do not report 
CAP or HAP and States that do not report HAP.
    This ``base alternative'' approach as just described would not 
resolve the potential issue of portable facilities that remain in a 
single location for a period that could impact local air quality. It 
also does not resolve the temporal aspect of such emissions. The 
information currently available to the EPA is that examples of such 
sources are not widespread enough to warrant the additional complexity 
associated with reporting a portable facility's emissions at multiple 
locations and/or multiple time periods. However, the EPA continues to 
seek information on the potential for portable facilities to adversely 
impact local air quality, what type of information would be useful to 
collect to better understand any air quality issues caused by such 
sources, and how the EPA could most effectively collect information 
from such sources.
    The 2017 NEI includes emissions reported by States from more than 
1,300 portable facilities such as asphalt plants. While most of these 
facilities are reported to emit actual emissions levels below the CAP 
PTE reporting threshold, some of these facilities included significant 
emissions for specific pollutants. For example, 41 portable facilities 
have between 20 and 177 tons

[[Page 54157]]

of NOX, and 5 facilities have between 20 and 243 tons of 
VOC. Two portable facilities contributed more than the proposed 
emissions reporting threshold of Pb emissions (0.074 tons). While these 
amounts are small nationally, they could significantly impact the local 
air quality if the source was stationary for a significant period 
within a year.
    Because the EPA recognizes that such portable sources, if 
stationary for long enough, could be an important local source, the EPA 
is proposing an option that may be included in the final rule, but is 
not currently included in the base alternative. The EPA is proposing 
that in addition to the base alternative, this ``Portable Definition 
Option'' would include a categorization of portable facilities to put 
them into two groups: (1) those that report as portable facilities as 
in the base alternative and (2) those that report as stationary 
sources. The EPA proposes that the two categories of portable 
facilities would have different reporting requirements as follows. 
Facilities would be defined as portable and required to report as 
portable sources only for periods when the source remains within a 1-km 
radius for fewer than 30 days. Facilities would be defined as 
stationary and be required to report as a stationary point source when 
the facility operates within a 1-km radius for 30 days or more. This 
Portable Definition Option would require the point source report to 
include the county identifier and coordinates of the centroid of its 
operations during each time period. The EPA would provide additional 
data formats that would support a requirement for States and owners/
operators to provide portable facility locations for each 30-day (or 
more) period using the start and end dates of operation within a 1-km 
radius (i.e., a single location could be provided associated with each 
30-day period). The EPA urges commenters who have information about 
such portable sources to comment about the advisability of EPA's 
proposed requirements under the Portable Definition Option.
    The EPA is also considering Alternative E1, that would replace the 
base alternative described above. Rather than require States to report 
portable sources as point sources, Alternative E1 would require States 
to report portable sources aggregated as county totals but include 
monthly emissions rather than annual emissions as in the base 
alternative. This alternative would allow States to track and aggregate 
all such portable facilities but report only by county and month. While 
the tracking of emissions from such sources would still be needed by 
States on a facility-specific basis, this option reduces the reporting 
complexity for States. For Indian tribes, this option would work in 
conjunction with the additional proposed requirements described in 
section IV.L of this preamble to report emissions from their boundaries 
disaggregated by the portion of their lands overlapping each county. 
This alternative would not be available to owners/operators. If the EPA 
were to adopt Alternative E1 in any final action, the EPA proposes that 
owners/operators would still be required to report as described in the 
base alternative. The EPA urges commenters to provide their ideas on 
the advisability of this alternative.

F. Reporting Deadlines for Point Sources

    In this proposed action, the EPA is proposing the dates by which 
point source requirements would be required to be met for States and 
owners/operators that are reporting emissions directly to EPA. We are 
also considering the interaction between the two types of deadlines. In 
this section, we discuss and propose State deadlines first followed by 
deadlines for owners/operators.
1. Deadlines for States for Point Sources
    The current AERR requires States to report point sources by 
December 31 of the year after the inventory year. Thus, for the 2020 
inventory year, the current State deadline is December 31, 2021. In the 
past, the EPA has used its enforcement discretion to allow States a 2-
week grace period to complete their emissions because of the holiday 
season in which the current deadline occurs. In this action, the EPA 
proposes to include what is now an unofficial grace period in the 
current AERR deadline for the 2023 through 2026 inventory years by 
setting the deadline to January 15 that occurs 1 year and 15 days after 
the end of the inventory year. For example, the deadline would be 
January 15, 2025, for the 2023 emissions inventory year. The EPA also 
proposes a phase-in to earlier point source deadlines starting with the 
2027 inventory year based on a variety of considerations described in 
this section.
    While most States receive data from point sources between March and 
October, most States do not start submitting point source emissions for 
the previous year until December. As a result, any problems that the 
States encounter in reporting their emissions in December often cannot 
be resolved in time to meet the current AERR deadline. In more rare 
cases, States have changed their software for handling emissions data, 
and it is either not working properly or not completed in time for 
States to meet regulatory deadlines.
    During the time between when States collect point source emissions 
data and when it is submitted, the States' role is to perform QA on 
emissions data, resolve any quality issues by having owners/operators 
resubmit their emissions, format the data for submission to EPA, and 
complete the EPA submission while resolving any QA errors sent by EIS. 
States also assess fees on the owners/operators of point sources based 
on emissions levels. The EPA is not aware of all the challenges that 
States face to complete these tasks but is aware of some of them as 
described next.
    States can have difficulty meeting any changes made to the EIS data 
elements or formatting requirements. For example, even with 18 months 
advanced notice, webinars, repeated reminders, and frequent newsletters 
that included information about changes to the EIS data format for 
controls, many States were left unaware of those changes as late as the 
fall of 2021 when the data were due in just a matter of weeks. The EPA 
recognizes that, even if States are working to ensure they meet any 
changes to the reporting approach, they may have limited time and 
resources to do so. States have also expressed concerns with their 
information technology departments when those departments are 
responsible for maintaining and revising State emissions reporting 
systems.
    Despite the challenges meeting the existing deadline, the needs and 
expectations for faster data turnaround continue to grow. While the 
public has become accustomed to hourly updates on ambient air quality, 
the emissions data lags years behind. The EPA's uses of the NEI all 
benefit from more timely receipt of data because the EPA can then use 
it to inform regulatory and non-regulatory analysis and decisions. With 
the current AERR deadline, the States have 1 year to submit their point 
source data, which is two-thirds or more of the time between the end of 
the inventory year and the first NEI point source release. The EPA has 
reduced the time it takes after receiving the data to combine State 
data with other data sources, quality assure the data, and augment the 
data to fill gaps or exclude flagged data that have not been addressed 
by States. While EPA continues to streamline its point source data 
processing efforts, only so much more improvement can be expected when 
States take the majority of the overall time it takes to release the 
inventory. By considering earlier State reporting deadlines, the EPA 
hopes to

[[Page 54158]]

achieve further improvement in timeliness of the point source NEI.
    Other EPA emissions inventory programs collect data directly from 
owners/operators, and their deadlines are earlier. For example, the TRI 
program collects data for a given reporting year from owners/operators 
by July 1 of the following year,\47\ releases a preliminary dataset by 
the end of July, and publishes the National Analysis dataset a few 
months later, typically mid- to late-October. The data are published 
from TRI before the NEI data are even due to be submitted by States. 
Another example is the GHGRP, which collects data from owners/operators 
by the end of March and publishes its results by October or 
November.\48\ While the States add value to the NEI reporting process 
by reviewing emissions data from point sources, the current approach 
requires more time than may be warranted.
---------------------------------------------------------------------------

    \47\ The TRI deadline is described in 40 CFR 372.30(d).
    \48\ The GHGRP deadlines are described in 40 CFR 98.2(i).
---------------------------------------------------------------------------

    The current timing of the NEI is unsatisfactory to EPA, some 
States, and the public. While everyone wants emissions data sooner, the 
collection, review, and publication of data for the NEI takes time, and 
resources are not always sufficient. Decisions and environmental 
improvements based on new information are delayed when the data take 
longer to produce.
    The disadvantages of less timely data have been known for years; 
however, the EPA is aware that one of the root causes of the time 
constraints have been resource limitations for the States. Until 
recently, the EPA has not had a potential solution to aid States in 
meeting their reporting requirements. By using CAERS for collecting 
emissions data from owners/operators of point sources, States now have 
a new option to assist in gathering, reviewing, and submitting high 
quality emissions data more quickly.
    State efforts to report for the NEI involve four primary steps for 
each inventory year: (1) configure a data reporting system; (2) support 
owners/operators using the reporting system, including training; (3) 
review data submitted by owners/operators for errors until owners/
operators resolve them; and (4) format data from the State system and 
submit it to the EIS. CAERS can reduce burden for states because the 
EPA makes sure that it is maintained with the latest AERR reporting 
requirements, which greatly reduces the State burden for maintaining 
the emissions reporting system. Since CAERS is integrated with the 
latest QA checks and uses the latest available emissions factors 
(including state-provided factors), States also can expect that data 
collected with CAERS is more likely to use the best available emissions 
estimation approaches. Finally, since CAERS converts and submits the 
data to the EIS, States can expect that the burden of that part of 
their role to be largely eliminated.
    In addition to the benefits of the existing CAERS approach for 
States, the EPA intends to further integrate CAERS with the WebFIRE 
database to provide direct access for owners/operators to the latest 
emissions factors and emissions rates they have reported to CEDRI (this 
would not change the public availability of the data in WebFIRE). 
Because this proposed action would require owners/operators to report 
certain source tests, this future CAERS advancement will streamline the 
use of these data by owners/operators and States. Usually, these source 
test data provide a better estimate of emission rates from facilities 
than do average emissions factors more traditionally used by States in 
their data systems. As a result, CAERS provides States a mechanism for 
both improved timeliness and improved emissions data quality.
    While the need for more timely data is clear, the challenges for 
States of any changes to an earlier deadline are significant. The EPA 
is considering that any proposed change in deadlines would need to be 
weighed against the time States would need to adapt to any new timing 
requirements as well as any other changes finalized based on this 
proposed action. While some States may have sufficient resources to 
continue to report data using their own data systems, they may need to 
change regulations and processes to adapt to an earlier deadline. The 
EPA has heard from States that it can take 2-3 years to change their 
emissions reporting regulations. Thus, States that must change those 
regulations to meet an earlier deadline would need time to do so.
    Other States that choose CAERS to help augment their emissions data 
collection and reporting approach may also need to change their 
reporting requirements, and they would need sufficient time to migrate 
from current processes to a CAERS-based approach. Depending on a 
variety of factors, this process can take between 1 and 3 years.
    Based on these considerations, the EPA proposes to add 15 more days 
to the point source reporting deadline through the 2026 inventory year. 
The deadlines for point source reporting for the 2023 through 2026 
inventories would be within 12 months and 15 days of the end of the 
inventory year (e.g., for the 2022 inventory year, by January 15, 
2024). This deadline and others are summarized below in section IV.S of 
this preamble.
    The EPA additionally proposes to establish point source reporting 
deadlines shorter than one year for inventory years 2027 and beyond. We 
propose to do this through a phase-in of earlier deadlines. With the 
preferred approach, the EPA proposes that for the 2027 through 2029 
inventory years, States would report point source data to the EPA 
within 9 months of the end of the inventory year (e.g., for the 2027 
inventory year, by September 30, 2028). Then, starting with the 2030 
inventory year and for every inventory year thereafter, States would be 
required to report point source data to the EPA within 5 months of the 
end of the inventory year (e.g., for the 2030 inventory year, by May 
31, 2031). The EPA is proposing to collect this data sooner than the 
current AERR requires because having more current data benefits EPA's 
work. Further, many States already have their data collected from 
owners/operators much earlier and submit it earlier than the current 
AERR deadlines. Other States can adjust to collect data earlier so they 
can report it earlier. CAERS could provide States an option for 
assistance with such an adjustment.
    In addition to this preferred approach, the EPA seeks comment on 
alternatives for phase-in of these earlier dates more gradually.\49\ 
Alternative F1 could provide for a slower phase-in of earlier point 
source reporting deadlines. The EPA is considering that the inventory 
year for the first deadline change could occur for inventory years 2028 
or 2029. The EPA is considering that the second deadline change could 
occur for inventory years 2031 or 2032.
---------------------------------------------------------------------------

    \49\ Faster phase-in of earlier reporting dates is not under 
consideration due to EPA resource and other implementation aspects 
necessary to support states in joining CAERS.
---------------------------------------------------------------------------

    The EPA is also seeking comment on Alternative F2, which provides 
alternative reporting dates for the earlier deadlines. The EPA urges 
commenters to suggest alternative deadlines, provide rationale 
supporting those other deadlines, or provide support for the deadlines 
proposed. For the first deadline change (under the preferred approach, 
starting for the 2027 inventory), the EPA is considering alternatives 
of August 31 and October 31. For the second (and final) deadline 
change, the EPA is considering

[[Page 54159]]

alternatives of April 1, April 30, and June 30.
    While the phase-in described in the preferred approach is the 
fastest approach under consideration, the EPA urges commenters to 
provide information and analysis if they believe such an approach may 
be too rapid, and which of the alternative phase-in dates would work 
better and why, or why the preferred approach is a good solution.
    In addition to the preferred approach and the alternatives on which 
the EPA is specifically soliciting comment, the EPA will consider 
appropriate combinations of phase-in timing as well as alternative 
deadlines. The EPA urges commenters to suggest alternative combinations 
of phase-in schedules and new deadlines if they believe that some other 
combination is appropriate, provide information and rationale that 
supports other combinations, or provide support for the preferred 
alternative.
2. Annual Emissions Deadlines for Owners/Operators of Point Sources
    As previously described in this preamble, the EPA is proposing 
annual emissions data reporting to the EPA from owners/operators of 
point sources, which can be either for HAP alone for facilities within 
States or both CAPs and HAP for facilities within Indian country and 
Federal waters. Additionally, owners/operators of point sources within 
Indian country may be required to report data for intermittent sources 
of electricity generation under certain circumstances. The EPA proposes 
deadlines for these requirements in this section.
    To explore the options for reporting by owners/operators, the EPA 
is considering four factors: (1) the amount of time it takes to prepare 
reports, (2) the availability of EPA's CAERS reporting system for each 
annual reporting cycle, (3) other emissions reporting deadlines that 
owners/operators must meet, and (4) coordination with State deadlines. 
Consideration of these factors allows for a phase-in for owners/
operators that synchronizes with any phase-in of earlier deadlines for 
States that may be finalized.
    First, the information an owner/operator needs to report emissions 
is largely collected during the year of the emissions inventory. For 
example, owners/operators keep track of their facility production rates 
throughout the year, fuel usage, and other throughput and activity data 
used to estimate emissions from each unit and process. For sources with 
CEMS, throughputs and emissions are available within days. Source tests 
performed during the year that would be required to be used under this 
action can be completed and reported to the EPA within 60 days. 
Emissions factors needed by sources are available on a continuous basis 
through AP-42 and WebFIRE, through CAERS, or via a State reporting 
system. For these reasons, the EPA expects that the data needed for 
owners/operators to report emissions to the EPA would be available at 
most within 60 days after the end of the inventory year.
    Second, the EPA has only been using CAERS for three emissions 
inventory years. For each of these, the EPA has successfully met 
objectives for including the States and associated owners/operators 
expected for each reporting year. While this proposed action, if 
finalized, is likely to greatly expand the adoption and use of CAERS, 
the EPA expects that it can continue the success of past experiences 
for future inventory cycles. The release date for CAERS for each 
inventory year is expected to be between February 1 and February 28 of 
the year after the inventory year.\50\ Thus, any deadlines that the EPA 
would consider should need to leave sufficient time between the CAERS 
release date and any due dates to accommodate owners/operators who 
report directly to the EPA under any final action taken on this 
proposal.
---------------------------------------------------------------------------

    \50\ For the 2022 inventory year, the EPA released CAERS for 
reporting on February 6, 2023.
---------------------------------------------------------------------------

    Third, other EPA reporting program deadlines are also important to 
consider from the perspective of owners/operations. For the GHGRP, 
reports are due by March 31 of each year and for the TRI, reports are 
due by July 1 of each year. The EPA understands that different owners/
operators could have different needs associated with any proposed 
timing requirements in this action. Some owners/operators may 
appreciate keeping the deadlines incremental, so that each requirement 
could be met in turn. This approach would allow industry staff to 
inform decision makers and report certifiers of the reports before they 
are sent. Other owners/operators could prefer the idea of consolidating 
reporting to multiple systems through CAERS, as well as consolidating 
deadlines.
    Finally, the EPA is also considering the relationship of the data 
being collected by each of the programs. The NEI program to relies on 
GHG emissions from the GHGRP where such reporting is required. This 
action does not propose allowing for owners/operators to voluntarily 
report GHGs to the NEI program (though States could continue to report 
them voluntarily). Therefore, the data connection between the GHGRP and 
the NEI is limited to the facility characteristics as well as the 
activity, such as fuel consumed, that may be used to estimate emissions 
both of GHGs and of pollutants required under any final version of this 
proposed action.
    The NEI program and the TRI program both collect emissions from 
each program's unique list of chemicals. As previously described, to 
meet programmatic needs, this action proposes to collect HAP emissions 
for individual units, processes, and release points within facilities. 
This proposed requirement is analogous to the current voluntary HAP 
reporting by States for NEI. For reporting by owners/operators, the HAP 
emissions estimated at the more detailed resolution for NEI could 
inform the air emissions portion of the TRI reporting requirement. In 
fact, the CAERS approach has recognized this potential connection 
between NEI and TRI for HAP; therefore, the EPA designed TRI-MEweb to 
access the emissions sums reported to CAERS for stack emissions and 
fugitive emissions when preparing a TRI reporting. This connection 
suggests that it may be beneficial to have an AERR deadline for owners/
operators be prior to the TRI reporting deadline.
    In addition to the other emissions reporting requirements, the EPA 
recognizes potential benefits of coordinating reporting deadlines for 
owners/operators with the proposed State reporting deadlines previously 
described. This coordination is particularly relevant considering that 
some States may choose to report HAP on behalf of owners/operators. The 
available options are for owners/operators to report before States 
submit data, at the same time, or after States' submissions. To address 
this issue, we explore a complex but streamlined example envisioned by 
this proposed action, whereby a State chooses to reduce its overall 
burden by participating in CAERS for CAPs but not adopt HAP reporting. 
In this case, owners/operators in that State would use CAERS to report 
HAP emissions directly to the EPA and report CAPs to the State. We 
expect that owners/operators would prefer to submit all their emissions 
together, rather than have different deadlines for different 
pollutants. With this example, the State would then need time to 
quality assure the CAP emissions and resolve any concerns with owners/
operators. For this example to work, the owners'/operators' deadline 
would necessarily need to precede the State deadline so that the State 
would have sufficient time to perform its review prior to passing

[[Page 54160]]

the data along to EPA. While other examples exist, the EPA has been 
unable to find another approach that addresses the needs for the 
implementation options included in this proposed action.
    As previously described, this action also proposes a phase-in of 
earlier deadlines for States. As a result, deadlines for owners/
operators would need to be adjusted in accordance with any changes to 
State deadlines.
    Based on these considerations, the EPA is proposing a requirement 
in which reporting from owners/operations would gradually increase. The 
EPA would allow reporting to be optional in the first year and then 
mandatory after that, as follows: Starting in the 2024 emission 
inventory year, owners/operators of facilities could optionally submit 
annual emissions data and any required daily fuel consumption for 
specific units by May 31, 2025. This would allow those owners/operators 
to report data directly to the EPA for any reason. The EPA additionally 
proposes that for the 2025 inventory year, any owner/operator of a 
point source that is located outside the geographic scope of the 
State's implementation planning authority would be required to report 
annual emissions data and any required daily fuel consumption for small 
generating units by May 31, 2026. Other owners/operators could continue 
voluntary reporting for the 2025 inventory year and then be subject to 
mandatory reporting for the 2026 inventory year. This would allow for a 
gradual increase in owner/operator reporting to ensure the CAERS system 
can best support owners/operators through the process. This approach 
would also allow the EPA to obtain data from sources within Indian 
country sooner than it otherwise would to fill a current gap in EPA's 
understanding of emissions.
    For the 2026 emissions inventory year, this action proposes that 
all owners/operators subject to reporting for point sources would 
complete submission of annual emissions and any required daily fuel 
consumption for specific units to the EPA by May 31, 2027. This 
requirement would apply both to point sources within Indian country as 
well as point sources within States that have not been approved for 
submission on behalf of owners/operators. Owners/operators within 
States that have been approved to report HAP on their behalf would not 
be subject to this proposed deadline (but rather to whatever deadline 
is imposed by the State).
    The proposed May 31 deadline is earlier than the TRI reporting 
deadline to address the relationship that exists between this proposed 
action and existing TRI requirements. The EPA is considering that an 
earlier date may not allow sufficient time for owners/operators to 
transition to submitting reports directly to the EPA for some or all 
their pollutants. In addition, for States that want to align their 
requirements with this date to provide owners/operators reporting CAPs 
to the State, the May 31 date provides States 7 months and 15 days to 
complete their tasks and meet the January 15 reporting deadline 
proposed for States for the 2024 and 2025 inventory years.
    Starting with the 2027 emissions inventory year and every year 
thereafter, this action proposes that owners/operators of point sources 
would complete submission of annual emissions and any required daily 
fuel consumption for specific units by March 31 of the year following 
the inventory year. The first date for meeting this requirement would 
be March 31, 2031, for the 2030 inventory year. This earlier date 
aligns with the second State earlier date phase-in to the proposed 
State reporting requirements of May 31, 2031.
    The EPA is aware that some industries may, due to workload 
concerns, have an interest in not aligning the proposed reporting 
deadline from facilities with the GHGRP deadline of March 31. Though 
the proposed approach described above would change the deadline for 
owners/operators from May 31 to March 31, the EPA continues to evaluate 
this proposed approach, and is requesting comment and additional 
information on the expected impacts of that proposed deadline. The EPA 
would also consider a later deadline for owners/operators that would be 
either April 15, April 30, or May 15 of the reporting year. The EPA 
urges commenters to describe additional considerations about which the 
EPA may not be aware of to advise on a reporting deadline for the final 
rule.
3. Summary of Reporting Deadlines and Phase-In Years
    Table 3 below provides a summary of the proposed point source 
reporting deadlines for annual emissions of the preferred approaches 
proposed in sections IV.F.1 and IV.F.2 of this preamble. These 
deadlines would not apply to the collection of source test data. This 
proposed phase-in approach is dependent on an assumed final 
promulgation date prior to June 2024. If a final version of this 
subpart were delayed beyond June 2024 or if comments on this proposal 
lead to an approach for a final rule, the EPA may delay the phase-in of 
earlier deadlines.

Table 3--Summary of Proposed Point Source Reporting Deadlines for Annual
                             Emissions Data
------------------------------------------------------------------------
                               Deadline in months after end of inventory
-----------------------------        year for reporting to the EPA
                             -------------------------------------------
            Phase                    States           Owners/operators
------------------------------------------------------------------------
Phase 1: 2022 through 2024..  12 months and 15      n/a.
                               days.
Phase 1: 2025...............  ....................  5 months (within
                                                     Indian country).
Phase 1: 2026...............  ....................  5 months (all
                                                     facilities).
Phase 2: 2027 through 2029..  9 months............  5 months.
Phase 3: 2030 and beyond....  5 months............  3 months.
------------------------------------------------------------------------

G. Point Source Reporting Frequency

    EPA is considering the frequency of point source reporting and is 
proposing that point source reporting be done for the same sources 
every year beginning with the 2026 inventory year. This proposed 
approach would eliminate the reduced reporting requirements on interim 
(non-triennial) years for point sources and would not affect the 
frequency of reporting nonpoint or mobile sources.
    By way of background, the current AERR requires point source 
reports from States for two categories of point sources: Type A and 
Type B (Table 1A to Appendix A of this subpart). States must report 
every year for Type A sources (which are point sources that exceed PTE 
reporting thresholds of 250 tpy for most CAP and 2,500 tons for CO, 
NOX, and SO2). No annual (i.e., only triennial) 
reporting threshold exists specifically for Pb, but Pb emissions are 
required to be reported annually when a source meets the PTE reporting

[[Page 54161]]

threshold for other pollutants above the Type A reporting thresholds. 
States must report every third year for Type B sources, which have 
lower reporting thresholds than the Type A sources. For parts of a 
State in attainment for a relevant NAAQS, the criteria pollutant and 
precursor PTE reporting thresholds for Type B sources are 100 tpy. For 
CO, the PTE reporting threshold for Type B sources is 1000 tons/year, 
and the Pb actual emissions reporting threshold is 0.5 tons. For 
nonattainment areas with a Serious designation or above, lower 
reporting thresholds for Type B sources exist for some pollutants, 
depending on the NAAQS for which an area is in nonattainment. As 
explained more below, the EPA is now proposing to do away with our 
approach to distinguish between Type A and Type B sources.
    The current triennial approach, which was designed in part to 
reduce burden on States, stems from the CAA section 182(a)(3) 
requirement for ozone for which States must submit a revised inventory 
no later than the end of each 3-year period after submission of their 
SIP base year inventory required for Marginal nonattainment areas and 
above. The EPA has continued this 3-year approach despite the expansion 
of the NEI to include PM and optionally HAP and GHGs.
    The EPA has found that the inventory for each year is important and 
useful to contribute to a variety of activities the EPA performs under 
the CAA. Having more information every third year and less information 
for other years has made it difficult for the EPA to effectively 
utilize the NEI data for certain purposes such as evaluating emissions 
trends, regulatory modeling, and non-regulatory modeling including 
national efforts to estimate risks from HAP. As described in sections 
IV.A.1 through IV.A.3 of this preamble, current HAP data needs to be 
readily available for having accurate information to support technology 
reviews and filling gaps in the MACT standards as per the LEAN decision 
previous described. Additionally, EPA's AirToxScreen will have access 
to more complete and current data to inform the public, support 
prioritization of compliance activities, and to inform understanding of 
risks faced by disadvantaged communities in support of various 
environmental justice priorities.
    The EPA has also experienced challenges with the current approach 
of more limited point source data on non-triennial years. For example, 
the Great Recession occurred between December 2007 and June 2009. Real 
gross domestic product did not regain its pre-crisis peak level until 
the third quarter of 2011. Thus, the bulk of the impact on industrial 
sources and reductions in their emissions occurred during 2009 and 
2010, two years when the NEI collected only the Type A data. Thus, the 
point source emissions inventory for those years did not reflect the 
full extent of the impacts on emissions of the Great Recession.
    Similarly, impacts from the COVID pandemic started in 2020 (a 
triennial inventory year in which we collected data from both Type A 
and Type B sources) and has continued into 2022. The pandemic has 
caused both activity decreases and facility closures for some 
industries as well as increases in activity for other industries. Other 
impacts to emissions-related activities caused by supply chain problems 
and price changes to fuels that may also have impacted emissions. The 
EPA anticipates that any potential impacts of the pandemic and 
industrial recovery on emissions could only be partially captured under 
the current AERR relying on Type A sources for non-triennial years.
    Because of greater data limitations for non-triennial years, the 
EPA has traditionally tried to rely on the triennial NEI for regulatory 
modeling of criteria pollutants, for example, for ozone transport 
analysis or an RIA for a new NAAQS. However, using a triennial NEI has 
not always been possible, because a modeling year is selected not only 
based on the emissions inventory, but also on the meteorological 
conditions that, in some years, lead to the formation of more ozone and 
more exceedances of the ozone NAAQS. When the EPA updates a NAAQS or 
transport rule and needs to perform an RIA and when States need to 
develop SIPs, it is important to use a modeling year that exemplifies 
the problem to be solved (e.g., a modeling year that models ambient air 
above the level of the NAAQS). This year is not always a triennial NEI 
year because of meteorological conditions and/or overly active fire 
seasons. In fact, EPA's most recent regulatory modeling platform was 
developed for 2016, which is not a triennial NEI year. A large amount 
of additional coordination with the States and multijurisdictional 
organizations was needed to refine the 2016 emissions to reflect 2016 
for Type B sources that had not been reported to the NEI.
    For regulatory analysis of HAP in support of future technology 
reviews under CAA 112(d)(6) and discretionary risk review, the EPA 
needs the most currently available data. For these reviews, the data 
need includes not only the actual emissions, but also the control 
technologies and other changes made to industrial facilities and their 
associated emissions rates for HAP. This is particularly important for 
the Technology Reviews for which the EPA is responsible for conducting 
periodically for each industry and in which the EPA considers 
developments in practices, processes, and control technologies. The 
emissions inventory data form the baseline emissions for Technology 
Reviews, which are a key component of EPA's analyses of potential 
control options, emissions reductions, and cost-effectiveness. The 
latest data about the controls and technologies at the facilities, 
provided by an emissions inventory, allow EPA to create a more 
effective and credible review. About 25 sectors per year need to 
undergo Technology Reviews each year, to meet the review schedule of 
every 8 years. If a HAP reporting requirement is finalized, continuing 
with a triennial approach would mean that the EPA would not always have 
the most up-to-date information for the Technology Reviews. Current 
limitations have required the EPA to conduct one-time efforts for 
providing additional data that could have already been available via a 
standardized NEI process.
    Annual HAP reporting will provide other benefits in addition to 
those discussed above. For example, the EPA has recently committed to 
providing annual updates of its air toxics data. The annual 
AirToxScreen will provide updated emissions and risk information, to 
both document the ongoing risks posed by some facilities and to provide 
communities with the information they need to understand those risks. 
The EPA intends to produce these updates annually to take advantage of 
the best available data and to help inform emissions trends, ideally to 
show progress in reducing risks to communities. Therefore, a triennial 
approach to collecting point source data would reduce the effectiveness 
of these efforts because all sources would not be updated on the same 
timescale.
    Not only does the EPA have an interest in having the most current 
information, but EPA's work with stakeholders has provided insights 
into the challenges owners/operators face when EPA includes outdated 
data in its NEI releases. For example, in the recent AirToxScreen 
releases for 2017 through 2019, some commercial sterilizer facilities 
had either ceased operating or installed additional controls to reduce 
ethylene oxide emissions. During review of these data prior to release, 
States and EPA regional office representatives heard from these 
facilities and informed EPA that they

[[Page 54162]]

wanted the agency to use the more current data because emissions were 
lower. Because these changes in operations had not occurred in the 
historical years, rather than adjust the modeled concentrations and 
risks in these historical years based on more current information, EPA 
added notices on the website for each of these facilities to indicate 
when operations ceased or when controls had been installed that would 
reduce emissions after the year of the AirToxScreen release. Similarly, 
when EPA used data that was several years old in support of regulatory 
decisions, in cases when one-time information collections could not be 
accomplished due to timing or other constraints, industry has commented 
about EPA's flawed data and insisted that more current data be used. 
With an annual approach for reporting emissions, the EPA could best 
reflect emissions controls and lower emissions in the NEI data, 
AirToxScreen, and regulatory assessments.
    Finally, as the EPA strives to best serve the public, EPA's ability 
to receive updated and timely emissions data provides a foundational 
piece of information needed to support many aspects of EPA's mission. 
This need is already illustrated by other EPA emissions data 
collections such as TRI, the GHGRP, and the Air Markets Program, which 
all collect data annually using consistent criteria each year.
    As described, the EPA has identified several limitations with the 
existing approach for which we receive more limited data 2 out of every 
3 years. It is important to resolve those limitations as quickly as 
possible to limit future impacts. The primary reasons for the triennial 
approach were (1) the original CAA basis of the rule as previously 
described, (2) the burden on States, and (3) the burden on the EPA to 
create an NEI every year. Each of these reasons has less weight now 
than it had for previous AERR revisions, as described in the following 
paragraphs. At the time these decisions were made, the burden on 
owners/operators was not considered; however, we are considering these 
burdens now. Even with these additional burdens on owners/operators 
considered, the EPA expects the benefits of the data collection to be 
justified.
    Regarding the original CAA basis for ozone and triennial periodic 
inventories, the EPA notes that inventories at least every three years 
are necessary to administer the ozone nonattainment area RFP provisions 
of section 182 (i.e., rate-of-progress, RFP, and milestone compliance 
demonstration provisions). The EPA also notes that the timing of ozone 
NAAQS nonattainment designations, which has implications for the 
inventory year that a State may select for their baseline inventory for 
the nonattainment area, does not necessarily align with the triennial 
inventory years established in the AERR. Thus, the EPA has allowed 
States to select the initial baseline inventory year (which serves as 
the RFP baseline year) using either the most recent triennial year or 
the year of the effective date of designation for that NAAQS. While 
there may be valid planning reasons for States to choose a non-
triennial year, the practical ability for States to do this can be 
constrained by the availability of adequate inventories during non-
triennial years. Moreover, with respect to the attainment demonstration 
obligation, modeled attainment demonstrations for ozone and PM may 
require base years other than triennial years to reflect meteorological 
conditions conducive to the nonattainment problems faced by a State. 
Thus, even though the Act requires a minimum triennial inventory 
approach for ozone nonattainment areas, experience suggests that having 
annually updated inventories provides benefits for criteria pollutant 
implementation in addition to the other benefits that will occur. 
Importantly, nothing in section 182 prohibits the EPA from requiring 
updated inventories on a more frequent basis.\51\
---------------------------------------------------------------------------

    \51\ See CAA section 182(a)(3)(A), which states that ``No later 
than the end of each 3-year period after submission of the inventory 
under paragraph (1) until the area is redesignated to attainment, 
the State shall submit a revised inventory meeting the requirements 
of subsection (a)(1) of this section'' (emphasis added).
---------------------------------------------------------------------------

    Since the 2008 promulgation of the AERR, technology for data 
collection and compilation has advanced significantly. Starting with 
the 2008 inventory year, the EPA provided the EIS to collect data 
electronically from States, and many States have developed their own 
electronic reporting approaches. The EPA has further refined and 
improved the EIS over time to provide additional QA, quality control 
(QC), and summary information features for State and the EPA inventory 
developers to help streamline the process and ultimately reduce burden 
for both States and EPA's NEI program. In addition, the EPA developed 
and released the CAERS application in 2019, which can support States 
that wish to have a more modern and robust emissions reporting system 
that meets AERR requirements. While the step of transferring State's 
emissions collection and reporting systems to CAERS has an initial up-
front (though voluntary) burden, the longer-term information 
technology, and programmatic efficiencies of sharing a reporting system 
with the EPA and other States would be significant.
    Although the motivations and new developments described above build 
a strong case for collecting the same point source data every year, the 
EPA is considering some additional information in evaluating the 
advisability of such an approach. This additional information includes 
what States have been reporting for non-triennial years voluntarily and 
the experiences of States that are already using CAERS for emissions 
reporting.
    The EPA recognizes that States have reported voluntarily more 
sources than required on non-triennial years. For the 2019 inventory 
year, for which States were required to submit only Type A sources, 34 
out of 82 State, local, and tribal agencies submitted roughly the same 
number of point sources as they submitted for the 2017 triennial year. 
This means that these States voluntarily submitted their triennially 
required sources instead of the fewer sources required. Some 
differences between years are to be expected because facilities open 
and close. These submissions represented about 11,000 facilities out of 
about 54,000 facilities submitted by agencies for either year, when 
considering those facilities that reported NOX, 
SO2, or VOC. Thus, because these 11,000 facilities represent 
about 20% of the 54,000 total facilities, we estimate that the 
incremental actual burden associated with requiring the same sources 
every year is about 20 percent lower calculated on a per-facility basis 
than it would be if these agencies were not already sending in such 
data. These States would meet an annual point source requirement 
without additional effort or burden (if the frequency change were the 
only change).
    To build on the 2017 and 2019 analysis, we compared emissions 
between 2017 and 2019 for those sources with 2017 emissions less than 
Type A reporting thresholds and which had emissions in both 2017 and 
2019. Sources that were not reported in both years were dropped. For 
NOX the median emissions increase or decrease between 2017 
and 2019 was less than 5 tons, which given the 100 tpy PTE reporting 
threshold is a small difference. This suggests that many sources do not 
change much from one year to the next. However, the NOX 
changes for any one facility ranged from an 1,800-ton decrease to a 
2,800-ton increase. In all, 672 facilities had emissions of 100 tons

[[Page 54163]]

or more in 2017 and more than a 25 percent increase or decrease in 
emissions in 2019. Similarly, for SO2, the median change 
between 2017 and 2019 was less than 1 ton, and the range of changes 
were a 1,900 ton decrease and a 4,600-ton increase. There were 347 
facilities with emissions of 100 tons or more in 2017 and more than a 
25 percent increase or decrease in emissions in 2019. For some of the 
uses of the NEI by the EPA and certainly for SIP inventories, the 
magnitude of these changes can be impactful in local areas. Thus, the 
EPA observes that including year-specific inventory data is important 
to promoting the quality and use of the NEI for the purposes laid out 
in sections IV.A.1 through IV.A.3 of this preamble and in this section.
    In discussions with States as part of the routine interactions 
associated with creating the NEI and as part of ongoing outreach for 
CAERS, State emissions inventory staff have volunteered the information 
to the EPA staff that they collect these point sources because of State 
regulations, and it is less work for them to report all the point 
sources every year rather than taking extra steps to limit what is 
reported in the non-triennial years. This response speaks to the 
benefit (for the vast majority of States with annual reporting 
regulations that include additional sources beyond those required by 
the AERR) of streamlining, automating, and taking the same approach 
each year.
    The EPA also is considering the experiences of States that are 
already using CAERS for emissions reporting. Transitioning to CAERS for 
these States has had its own one-time challenges, in part because the 
system is new. Other than those initial challenges, however, the 
States' experience using CAERS for the 2018 through 2020 inventory 
years has been that their work is primarily focused on supporting 
facilities and quality assuring data, rather than setting up their data 
system or formatting data from the State system and submitting it to 
the EIS.\52\ Since CAERS includes the QA checks in EIS for owners/
operators to get feedback and make corrections while reporting, once 
the data has been accepted by CAERS, it largely can flow to the EIS 
without much effort for States.
---------------------------------------------------------------------------

    \52\ See ``Georgia Partners with the EPA to Pilot Combined Air 
Emissions Reporting System'' and ``From CHAOS to CAERS: Improving 
Inventory Reporting Workflows in the District of Columbia,'' which 
are both available in the docket for this proposal.
---------------------------------------------------------------------------

    Based on these considerations, the EPA proposes to change the 
reporting thresholds so that they are the same for all years (EPA will 
no longer distinguish between Type A and Type B sources). Further, the 
EPA proposes implementation of this requirement to take effect the 
first non-triennial year after promulgation of the final rulemaking for 
this proposed rulemaking (expected to be 2027).
    The EPA is also considering whether the 2027 inventory year is too 
soon for some States to implement changes that would enable them to 
collect data from all point sources that otherwise would not be 
reported until the 2029 inventory year. Thus, the EPA is considering 
Alternative G2 to use the 2028 inventory year as the first year for 
implementation of the same reporting thresholds every year. The EPA is 
interested in comments about the feasibility of the base alternative of 
a 2027 inventory year requirement (data would be due by September 30, 
2028, under the preferred phase-in alternative described in section 
IV.F.1 of this preamble) when compared to Alternative G2 that would use 
a 2028 inventory year requirement (data would be due by September 30, 
2029, under the preferred phase-in alternative).
    Irrespective of the implementation challenges for States, the EPA 
is proposing that owners/operators within States not reporting on their 
behalf would report annual emissions data for the same sources every 
year beginning with the 2026 inventory year. As previously described, 
the EPA is proposing that owners/operators operating facilities within 
Indian country and Federal waters would report annual emissions data 
for all applicable sources beginning with the 2025 inventory year. The 
requirement for annual reporting by owners/operators is based on the 
importance of year-specific data for many sources and EPA's ability to 
implement CAERS for many new reporters. Nevertheless, the EPA is 
interested in comments providing information and analysis about the 
feasibility for sources to report directly to the EPA voluntarily for 
the 2024 inventory year in two cases: (1) facilities that are within 
the geographic scope of a State's implementation planning authority and 
(2) all other facilities. In the first case, if there would be 
unforeseen challenges for States or owners/operators in the case where 
owners/operators are reporting HAP when the State is reporting CAPs, it 
would be helpful for commenters to provide information on any such 
challenges so the EPA can better evaluate the options it is considering 
in this rulemaking.
    A provision of the current AERR in 40 CFR 51.35 provides States the 
opportunity to submit Type B point sources over a 3-year period to 
spread out their emissions inventory work rather than have a reporting 
burden spike in the triennial years. For point sources, this existing 
provision at Sec.  51.35(a)(2) says that States may ``collect data for 
one-third of your sources that are not Type A point sources.'' That 
provision continues by including ``Collect data for a different third 
of these sources each year so that data has been collected for all of 
the sources that are not Type A point sources by the end of each 3-year 
cycle. You must save 3 years of data and then report all emissions from 
the sources that are not Type A point sources on the triennial 
inventory due date.'' The advantage of this provision is that States 
can balance state workload. With the annual reporting for all sources 
proposed in this action, the EPA is additionally proposing to remove 
the provisions of 40 CFR 51.35 in the current AERR.

H. Clarification About Confidential Treatment of Data

    The existing requirements in the AERR include a statement about 
confidential data at 40 CFR 50.15(d), which states ``[w]e do not 
consider the data in Tables 2a and 2b in Appendix A of this subpart 
confidential, but some States limit release of these types of data. Any 
data that you submit to the EPA under this subpart will be considered 
in the public domain and cannot be treated as confidential. If Federal 
and State requirements are inconsistent, consult your EPA Regional 
Office for a final reconciliation.'' This section of the current AERR 
was intended to clarify that the data required to be reported to the 
EPA under the AERR would not be treated as confidential by EPA.
    The context of this discussion and clarification on confidential 
data and the NEI relates to EPA's intent to continue its current 
practice of releasing point source emissions data on a regular basis. 
Point source emissions data collected by the Agency will be available 
to States and EPA staff via the EIS within months of its receipt. The 
EPA expects to make such data publicly available via EPA's website 
within the year after receipt. While some data fields may not currently 
be published on EPA's website, the EPA provides that data upon request. 
The EPA may change the composition of the data published, timing, or 
method of any release of collected information without further notice.
    Since the provision in Sec.  50.15(d) of the current AERR was 
promulgated, it has led to some confusion that the EPA is now seeking 
to clarify with revisions.

[[Page 54164]]

For example, the EPA has received claims by States that, under the 
current AERR, they do not need to report some data to the EPA because 
the State considers that data entitled to confidential treatment. One 
local air agency claimed that it could not report SCCs that describe 
the emissions process to the EPA under the requirements of the AERR 
because it claimed that information was confidential under State law. 
Other agencies do not report the throughput data from their sources, 
despite it being a required field currently in the AERR. The EPA's 
understanding of the reasons for withholding such required data is that 
States consider the throughput data to be confidential so the local 
agencies cannot report it. The EPA recognizes that the existing wording 
of Sec.  50.15(d) could be confusing and could contribute to the lack 
of reporting for certain data elements. Nevertheless, the existing 
language of Sec.  50.15(d) was not intended to allow States not to 
submit certain data or to claim required data as entitled to 
confidential treatment from EPA.
    To address this confusion and to articulate more clearly EPA's 
position on confidentiality for all information States and owners/
operators are required to report under the AERR, the EPA proposes to 
add language to clarify the classification of data collected under this 
action. In addition, the EPA is proposing changes to clarify that those 
parties required to report under this subpart cannot decline to report 
certain data elements based on a claim that the data is entitled to 
confidential treatment. Specifically, the EPA proposes to add the 
determination that all data that parties are required to report under 
the revised AERR, including the data from the additional categories 
associated with emissions testing, is ``emissions data'' as defined at 
40 CFR 2.301(a)(2)(i). As emissions data, the reported information is 
not subject to confidential treatment in accordance with CAA section 
114(c), which provides for the public disclosure of such information. 
This proposed revision is intended to clarify that the EPA will not 
treat any data reported to the EPA under this rule (including the HAP 
data) as confidential in accordance with CAA requirements for emissions 
data and that entities who are responsible for reporting cannot 
withhold information based on claims of confidentiality.
    The EPA also proposes to amend 40 CFR 2.301 to clarify that 
information the EPA collects through the AERR is emission data that is 
not subject to confidential treatment. Within that subpart, Sec.  2.301 
includes regulations governing certain information obtained under the 
CAA. Section 2.301(a)(2)(i) defines the term emission data ``with 
reference to any source of emission of any substance to air'' to mean 
under paragraph (A) ``information necessary to determine the identity, 
amount, and frequency, concentration, or other characteristics (to the 
extent related to air quality) of any emission which has been emitted 
by the source (or of any pollutant resulting from any emission by the 
source), or any combination of the foregoing.'' In addition, the 
definition is further established by Sec.  2.301(a)(2)(i)(B) to include 
``[i]nformation necessary to determine the identity, amount, frequency, 
concentration, or other characteristics (to the extent related to air 
quality) of the emissions which, under an applicable standard or 
limitation, the source was authorized to emit (including, to the extent 
necessary for such purposes, a description of the manner or rate of 
operation of the source).'' Lastly, Sec.  2.301(a)(2)(i)(C) further 
defines emission data to include ``[a] general description of the 
location and/or nature of the source to the extent necessary to 
identify the source and to distinguish it from other sources 
(including, to the extent necessary for such purposes, a description of 
the device, installation, or operation constituting the source).''
    Also codified in Sec.  2.301(a)(2)(ii) are certain exceptions to 
the general rule of paragraph (i) described above. This paragraph 
elaborates that certain information ``shall be considered to be 
emission data only to the extent necessary to allow the EPA to disclose 
publicly that a source is (or is not) in compliance with an applicable 
standard or limitation, or to allow the EPA to demonstrate the 
feasibility, practicability, or attainability (or lack thereof) of an 
existing or proposed standard or limitation.'' If these conditions do 
not apply, then Sec.  2.301(a)(2)(ii)(A) excludes from the definition 
of ``emission data'' any ``information concerning research, or the 
results of research, on any project, method, device or installation (or 
any component thereof) which was produced, developed, installed, and 
used only for research purposes.'' Similarly, Sec.  2.301(a)(2)(ii)(B) 
excludes ``[i]nformation concerning any product, method, device, or 
installation (or any component thereof) designed and intended to be 
marketed or used commercially but not yet so marketed or used.''
    With this action, the EPA is proposing to determine that all data 
that would be required to be reported or optionally reported under the 
proposed AERR revisions are emission data as defined by 40 CFR 2.301. 
To support this proposed determination, the EPA has created a list of 
the optional and required point source data elements for annual 
emissions data and has identified the part of 40 CFR 2.301 that applies 
to each element. The spreadsheet ``AERR point source data 
elements.xlsx'' provides this information and is available in the 
docket. Point source data elements are particularly relevant to 
considerations of confidentiality since individual point sources are 
owned by business interests and the data that the EPA collects is 
highly detailed. Point source data are also the type of information 
that has been claimed as confidential in the past.
    In addition to the list of point source data elements described 
above, source test data collection included in section IV.C of this 
preamble describes collection of source test data. The EPA proposes 
that all required data elements for the ERT and such additional data 
that owners/operators would need to include when reporting source test 
data under this proposed action classify as emissions data. For 
example, this action proposes to require load, process operation, and 
parameter data, and all of these are necessary to develop emissions 
factors. The EPA identifies these data elements as meeting the 
definition of emissions data because they are, as per from 40 CFR 
2.301(a)(2)(i)(B), ``other characteristics'' needed to provide ``a 
description of the manner or rate of operation of the source'' that the 
EPA needs ``to determine the identity, amount, frequency, 
concentration, or other characteristics (to the extent related to air 
quality) of the emissions.''
    For States, the emissions reporting requirement for annual total 
emissions extends to all the types of sources listed under Sec.  51.15 
of the proposed regulatory text. The data that would be required under 
the proposed Sec.  51.15 includes totals of pollutants, activity 
creating the emissions, characteristics of the sources, and in some 
cases model input and documentation. States would be required to report 
for point sources, aircraft and GSE, rail yards, nonpoint sources, 
onroad mobile, nonroad mobile, and prescribed fires. States would be 
able to optionally report wildfire and agricultural fire data. The EPA 
is proposing to determine that all the required and optional data 
fields, including those listed above, to be reported by States for all 
these sources meet the definition of emissions data and, therefore, are 
not subject to confidential treatment under the CAA.

[[Page 54165]]

Moreover, States would optionally be able to report wildfires and 
agricultural fires.
    For example, the type of pollutants, magnitude of those pollutants, 
and emission rates of a source all meet the definition of emission data 
under paragraph 40 CFR 2.301(a)(2)(i)(A) as ``information necessary to 
determine the . . . amount, . . . concentration, or other 
characteristics (to the extent related to air quality) of any emission 
which has been emitted by the source.'' In addition, data elements that 
identify the source of any such emissions, such as the location, name, 
industry codes, units, processes, release points, controls, and all 
their characteristics all serve as ``information necessary to determine 
the identity'' of such emission data as per the Sec.  2.301(a)(2)(i)(A) 
definition. Many required data elements meet the definition of Sec.  
2.301(a)(2)(i)(C) in that they ``identify the source and distinguish it 
from other sources (including, to the extent necessary for such 
purposes a description of the device, installation, or operation 
constituting the source).'' Examples of data elements that meet this 
definition in paragraph (C) include any data elements related to (1) 
installation dates of units, processes, and controls; (2) effective 
dates of use for units, processes, release points, and controls; and 
(3) the throughput of each emission process for both annual reporting 
and source test data reports. Many of the data elements about source 
characteristics that meet the definition under Sec.  2.301(a)(2)(i)(A) 
also meet the definition provided under Sec.  2.301(a)(2)(i)(C).
    This action proposes various requirements that relate to what 
information is entitled to confidential treatment. First, this proposal 
includes requirements through listing of data elements. Data elements 
for annual reporting of point sources are listed in Tables 2a and 2b to 
Appendix A of Subpart A to Part 51. The source test reporting that the 
EPA proposes in section IV.C of this preamble requires use of the ERT; 
therefore, this proposal contains those elements required to use ERT, 
and additionally requires four data elements that would otherwise be 
optional if we had relied only on the mandatory reporting requirements 
of the ERT.
    The proposed determination that all data required to be reported by 
the AERR are ``emissions data'' serves two purposes: (1) to re-state 
and clarify EPA's position on the data that the current AERR is 
collecting and would continue under any final action, and (2) to apply 
to the newly added data fields the EPA is proposing to require (as per 
section IV.I of this preamble). Therefore, this proposed 
confidentiality determination is intended to apply to both the current 
AERR and the proposed AERR revisions.
    There are some required data elements included in the proposed 
requirement to use electronic reporting via the EIS, CAERS, and CEDRI 
that do not meet the definition of emission data. These are data 
elements that identify the individuals responsible for submitting such 
data and their contact information. While this submitter information 
does not meet the definition of emission data, the Agency is making a 
final determination through this rulemaking that this contact 
information does not meet the standard for confidential treatment under 
5 U.S.C. 552(b)(4) and upon finalization of this rule, may be released 
to the public without further notice to the submitter. These data 
elements do not meet the definition of emission data, but also do not 
meet the definition of information needing confidential treatment.
    Based on these considerations, the EPA proposes to determine that 
all data elements collected by the AERR are emissions data not entitled 
to confidential treatment, and thus that the EPA may release this 
information to the public without further notice to the submitter upon 
finalization of this rule. To implement this determination, the EPA 
proposes to add paragraph (k) to apply to data required to be submitted 
under 40 CFR 2.301.

I. Additional Point Source Reporting Revisions

    The EPA has identified new requirements for point sources, new 
voluntary data elements, and various clarifications. New requirements 
include both the formalization of special cases that have previously 
been handled voluntarily and completely new required data elements. 
Clarifications include those for existing requirements that will newly 
be enforced by EPA data systems as well as clarifications for how to 
report certain data.
1. Formalizing the Approach for Aircraft and Ground Support Equipment
    Over the past four or more triennial inventory years, the EPA has 
developed a comprehensive inventory of all airports to support analyses 
that may result in new regulations affecting emissions sources at 
airports, including aircraft and GSE. These sources can additionally be 
sources of HAP and impact communities, especially when the boundaries 
of airports are close to housing, schools, and workplaces. Most 
airports do not meet the emissions reporting thresholds for CAPs that 
are in effect through this subpart, and many will not meet the 
reporting thresholds for HAP proposed by this action. When stationary 
sources at airports meet point source reporting thresholds, States 
currently report emissions of stationary sources at airports (e.g., 
boilers) as stationary point sources, and this approach is unchanged by 
this proposed action. However, other approaches are necessary for 
aircraft and GSE to ensure a complete airport inventory.
    To date, the EPA has worked with States during previous triennial 
emission inventory years through voluntary review of LTO data for all 
airports. In past triennial inventory years, the EPA compiled and 
distributed the LTO data for voluntary State review and accepted 
comments and revisions to that data from States. The EPA estimated 
emissions using the final LTO data as input to the Federal Aviation 
Administration (FAA) Aviation Environmental Design Tool (AEDT).\53\ 
This model includes emissions from aircraft up to 3,000 feet from the 
surface, and past guidance to States on airport emissions was to use 
that same elevation as part of the ``point source'' emissions. The 
resulting emissions data from aircraft and ground support equipment 
using these methods provide a fallback estimate of emissions from these 
sources at airports not reported by States.
---------------------------------------------------------------------------

    \53\ Aviation Environmental Design Tool website, https://aedt.faa.gov/.
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    In assessing States' compliance with the provisions of the current 
AERR, the EPA has previously accepted the States' provision of LTO data 
as being sufficient to meet the point source requirements for those 
airports that exceed the point source reporting thresholds. This 
approach both reduces burden for States as well as provides the EPA 
relevant information for use of the AEDT to estimate emissions. When 
the NEI includes EPA-created emissions, the EPA and the public have 
full transparency about how the data have been created including QA 
steps. The approach also creates a consistent dataset for all airports 
to use in QA of state-provided annual total emissions submitted, and it 
allows the EPA to use the latest available AEDT version. This last 
advantage allows the EPA to use AEDT updates that may be released by 
the FAA after the State point source reporting deadline.
    Collection of LTO data provides the most advantage when used 
consistently across all airports. While airport

[[Page 54166]]

emissions data provided by States is also useful, when LTO data are not 
also provided, the EPA then lacks a consistent basis for comparing the 
AEDT results it creates with the state-reported emissions. Furthermore, 
without documentation provided about state-reported emissions, the EPA 
does currently require the method by which the State estimated 
emissions or performed QA, unless the EPA and the State incur the 
further burden of follow-up outside the existing electronic reporting 
process. The EPA has observed that implementing follow-up steps for 
clarification is less efficient than using a process by which the 
information is required from the outset.
    Given these considerations, the EPA is proposing distinct 
requirements for reporting of aircraft and GSE data by States, which 
differ from the more general point source requirements. This action 
proposes in 40 CFR 51.15(b) to add two options for States to report 
data for airports in triennial years: either (1) submit LTO activity 
data for some or all airports within the geographic scope of the 
State's implementation planning authority using formats provided by the 
EPA and/or (2) review LTO data and annual emission totals provided by 
the EPA, send comments on that data, and notify the EPA that the State 
accepts that data. Under this proposed addition, States can choose one 
of these two options for each airport for which they would be required 
to report. The EPA additionally proposes that the deadline for 
reporting activity data would be by September 30 of the year after the 
inventory year, or 60 calendar days after the EPA provides airport data 
to a State, whichever is later (i.e., for the 2023 inventory year, by 
September 30, 2024, or later). This deadline and others are summarized 
below in section IV.S of this preamble.
    In addition, the EPA is considering that there is a distinction 
between emissions from stationary source units (e.g., boilers) at 
typical point sources as compared to the emissions from aircraft and 
ground support equipment. To the extent that an airport has emissions 
sources other than aircraft and ground support equipment, and the 
emissions from the airport exceed the point source reporting thresholds 
included in this proposed action, those additional stationary sources 
should be reported consistent with non-airport point source 
requirements. For example, if a boiler is run at an airport for heating 
and the total airport emissions cause the airport to meet the point 
source reporting thresholds, then emissions from that boiler would need 
to be reported under this proposed action. To clarify this point, the 
EPA proposes that States must report stationary sources and qualifying 
mobile sources as per IV.I.16 of this preamble (other than aircraft and 
GSE) at airports.
    States may voluntarily submit annual total emissions for aircraft 
and GSE for some or all airports. However, the EPA is proposing a 
requirement that if a State chooses to report annual total emissions, 
they would be required to: (1) use the latest airport emissions model 
specific in the NEI plan, (2) submit all pollutants estimated by the 
latest airport emission model, and (3) submit documentation that 
describes how States used the model to estimate emissions and performed 
QA steps.
2. Formalizing the Approach for Rail Yards
    Like airports, rail yards may sometimes meet the existing 
definition of point sources under this subpart, and with this proposed 
action including HAP emissions reporting thresholds described in 
section IV.A.8 of this preamble, additional rail yards may be defined 
as point sources for the AERR in the future. Rail yard data include 
emissions from yard locomotive switchers and can include other 
emissions sources if present. As with airports, the Agency's goal of 
complete emissions is supported by a comprehensive inventory of 
emissions associated with locomotives to support analyses that may 
result in new regulations affecting these sources. Rail yards have also 
been identified as important sources of HAP in some communities.\54\ 
For these reasons, the EPA has reviewed its approach for rail yard 
emissions, which has many similarities to the airport approach.
---------------------------------------------------------------------------

    \54\ Spencer-Hwang, R., Montgomery, S., Dougherty, M., 
Valladares, J., Rangel, S, Gleason, P, Soret, S, Experiences of a 
Rail Yard Community: Life is Hard, J Environ Health. 2014 Sep; 
77(2): 8-17. Eiguren-Fernandez, A, Exposure to Rail Yard Emissions 
and Possible Health Impacts on Adjacent Communities, Center for 
Occupational and Environmental Health, Southern California Particle 
Center, October 4, 2010, http://www.scientificintegrityinstitute.org/coehrail100410.pdf.
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    EPA works with rail companies who voluntarily provide activity data 
about rail yards for point sources and locomotive activity for nonpoint 
sources. Emissions from both rail yards and locomotives are 
interrelated, and a complete accounting of these sources and activities 
would create a comprehensive and consistent emission inventory across 
these activities. Accounting of rail yards cannot be only for those 
that meet the definition of point sources because data from all rail 
yards are needed to fully understand the locomotive emissions on rail 
lines and achieve a complete inventory.
    In past triennial inventory years, the EPA provided the rail yard 
data for voluntary State review and accepted comments and revisions to 
that data from States. The EPA estimated emissions relying heavily on 
collaboration with the Eastern Research Technical Advisory Committee 
(ERTAC). The resulting emissions data for rail yards provided a 
fallback estimate of emissions at rail yards not reported by States.
    In assessing States' compliance with the current AERR, the EPA has 
previously accepted the States' provision of rail activity data as 
being sufficient to meet the point source requirements for those rail 
yards that exceed the point source reporting thresholds. This approach 
both reduces burden for States as well as provides the EPA information 
to estimate emissions. When the NEI includes EPA-created emissions, the 
public has full transparency about how the data have been created 
including QA steps. The approach also creates a consistent dataset for 
all rail yards to use in QA of state-provided annual total emissions 
submitted, and it allows the EPA to use the latest available emissions 
estimation approaches.
    As with airports, the existing voluntary approach with States 
provides the most advantage when used consistently across all rail 
yards. This is true for the same reasons as for airports and to meet 
EPA's interest in comprehensively understanding rail yard emissions to 
best meet Agency goals.
    In the past, many States have not had an independent source of data 
other than that provided by EPA. One approach for States to obtain that 
data would be for States to require it from rail companies; however, 
since rail companies operate across State boundaries, it is preferable 
for these companies to work directly with a central coordinator like 
the EPA and ERTAC. Nevertheless, nothing in the existing requirements 
of this subpart or any proposed requirements of this action would 
prevent States from collecting such information from rail companies if 
such data were not otherwise available.
    Unlike the publicly available LTO data for airports, the current 
rail yard approach for the NEI relies on voluntary reporting by a 
limited number of existing rail companies. While this approach has 
mutual benefit to both the EPA and those companies, it is nevertheless 
a voluntary measure. Thus, in formulating the requirements under

[[Page 54167]]

this proposed action, the EPA is considering the possibility that rail 
companies may not provide data voluntarily for one or more triennial 
years. This exact situation has been experienced by the EPA for the 
2020 triennial inventory. In this case, this proposed action must 
consider that the EPA cannot offer States an option to reduce State 
burden by compiling the rail yard activity when such data are not 
provided by rail companies.
    Given these considerations, the EPA is proposing distinct 
requirements for reporting of rail yard data by States, which differ 
from the more general point source requirements. This action proposes 
in Sec.  51.15(c) to add two options for States to report data for rail 
yards in triennial years. States may either (1) submit rail yard 
activity data and documentation for some or all rail yards within the 
geographic scope of the States' implementation planning authority using 
formats provided by the EPA or (2) review rail yard data and annual 
emission totals provided by EPA, submit comments on that data, and/or 
notify the EPA that the State accepts that data. This second option is 
available to States because rail companies voluntarily provide rail 
yard data to the EPA (included as part of the voluntary burden 
estimates for this proposed action). This voluntary data flow is likely 
more convenient for rail companies than if each State needed to collect 
data from them individually to meet the provisions of these proposed 
requirements.
    The EPA is additionally proposing that States may voluntarily 
submit annual total emissions for some or all rail yards, and if a 
State chooses to report emissions would then be required to meet the 
following requirements for the EPA to consider using such data. The EPA 
is proposing to consider state-submitted emissions data for rail yards 
only when the State: (1) submits all pollutants estimated by EPA's rail 
yard emissions method to be used for the relevant inventory year 
(described by the NEI Plan) and (2) submits documentation that 
describes how States calculated annual total rail yard emissions and 
performed QA steps.
    While the proposed approach above is EPA's preferred approach, the 
EPA is also considering a ``Rail Companies'' Option that would 
additionally regulate the rail companies directly to provide activity 
data to EPA. For the Rail Companies Option, the EPA proposes that 
owners/operators of rail companies would be required to report activity 
data from of those yards to EPA. The Rail Companies Option would have a 
disadvantage of imposing more requirements than continuing the ongoing 
voluntary approach with rail companies. The EPA requests comment on the 
Rail Companies Option and urges commenters to provide any additional 
information that would be helpful to the EPA in deciding between a 
voluntary and mandatory rail yard activity reporting approach.
3. New Requirements for Point Source Control Data
    Since the EPA started collecting emissions data through the EIS, 
some States have made the EPA aware that allowing States to specify 
controls was insufficient to appropriately allow specification of the 
necessary details. In the current control device reporting requirements 
of this subpart, States have been unable to describe fully how controls 
are configured at a facility (e.g., series or parallel), define the 
relationship among multiple control measures and the units, processes, 
and/or release points at a facility, or reuse the definition of a 
control measure in the dataset so that the same control measure can be 
associated with more than one unit, process, or release point. Such 
control configuration information is relevant to certain uses of the 
NEI, such as Technical Reviews and Regulatory Impact Analyses.
    Based on this understanding, the EPA is proposing a requirement to 
specify controls to remove the limitations of the current requirements. 
This new proposed requirement would use a list of control measures for 
a facility that is analogous to those control measures that exist in 
the real world, wherein each control would define only a single piece 
of control equipment or control measure, and a control path can be 
defined that would allow control measures to be arranged in any 
configuration of series and parallel control measures.
    This action proposes revisions to the data elements required for 
specifying controls. This proposed action adds new data elements in 
Table 2a to Appendix A of Subpart A to Part 51. These proposed data 
elements include control paths, which are defined as one or more 
controls at a facility that are linked. The path can consist of groups 
of control measures or other paths in parallel or in series. The 
proposed data elements also include control apportionment, which is 
defined as the percentage of the emissions that flows to the next 
control or path, and control assignment, which defines the sequence in 
which controls are configured within a path. Other proposed data 
elements to specify controls are similar to existing requirements, such 
as the pollutants affected, and percent reduction achieved. to Appendix 
A. More information on controls is available in Appendix A of the CAERS 
User Guide.\55\
---------------------------------------------------------------------------

    \55\ Combined Air Emissions Reporting System (CAERS) User's 
Guide, Version 2.0, U.S. EPA, 2/25/2021, https://www.epa.gov/e-enterprise/combined-air-emissions-reporting-system-caers-users-guide.
---------------------------------------------------------------------------

4. New Requirements for Point Source Throughput in Specific Units of 
Measure
    The EPA has observed during past triennial inventory cycles a 
potential for double counting of emissions from stationary sources of 
fuel combustion, because those sources exist both in the point source 
and nonpoint data categories. Stationary fuel combustion for point 
sources occurs at sources that meet the point source reporting 
thresholds while fuel combustion for nonpoint sources reflects 
emissions from smaller commercial and institution facilities such as 
shopping malls, office buildings, municipal buildings, and hospitals. 
These nonpoint emissions are captured in the NEI through the 
industrial, commercial and institutional (ICI) fuel combustion sectors, 
and these sources are a significant portion of the total emissions 
inventory for many areas. For example, according to the 2017 NEI, 
statewide NOX from ICI combustion sources represented up to 
27 percent of NOX, with a median of 9.1 percent over all 
States, when calculated by excluding fires and biogenic sources from 
the total. Using the same calculation approach, statewide 
PM2.5 from ICI combustion sources represented up to 28 
percent of statewide PM2.5 with a median of 3.2 percent. 
Nonpoint commercial and institutional fuel combustion includes 
emissions from boilers, engines, and other combustion sources that burn 
natural gas, biomass, distillate fuel oil, residual fuel oil, kerosene, 
liquefied petroleum gas (LPG), and coal.
    The EPA's approach to capture nonpoint ICI fuel combustion uses 
statewide fuel consumption data from the U.S. Energy Information 
Administration for the various fuel types and allocates it to counties 
based on employment in the industrial or commercial sector from the 
Census Bureau's County Business Patterns data. The EPA makes numerous 
adjustments to the fuel consumption based on various data available to 
EPA, such as subtracting nonroad source fuel consumption and non-
combustion uses from State total fuel use.
    To avoid double counting with point source emissions, the EPA 
currently

[[Page 54168]]

provides, as part of the nonpoint data collection, various options for 
States to supply point source fuel consumption. Some States, however, 
do not provide such data in part because they do not have that data 
from facilities. Over many triennial NEI years, the EPA has observed 
that some States claim that their State does not have any nonpoint fuel 
consumption; however, the EPA finds this claim implausible given that 
those States do not include every shopping mall, office building, 
municipal building, and hospital in their point source inventory. As a 
result, the EPA has had to make assumptions about point source fuel 
consumption to subtract it from the nonpoint fuel consumption totals. 
These assumptions reduce the accuracy of the inventory. Such inaction 
on the part of States directly contradicts the CAA section 172(c)(3) 
requirement for ``comprehensive, accurate'' inventories. Furthermore, 
this issue is not only significant for the NEI, but also is relevant 
for emissions inventories required under the Ozone and PM2.5 
SIP Implementation Rules.
    To date, the EPA has attempted to resolve the issue through 
collection of total point source fuel use by each State as part of the 
nonpoint ICI data collection. The EPA has experienced that some States 
continue to avoid this requirement by making implausible claims that 
all such sources for all fuel types do not exist or stating that States 
lack the data. Given the importance of such information to States and 
EPA, the EPA is proposing action to ensure States are aware of this 
issue and to support creation of accurate ICI fuel combustion emissions 
for both point and nonpoint sources.
    Further, the EPA recognizes the potential for directly receiving 
such information from owners/operators of point sources as part of the 
requirements proposed by this action. To address the connection with 
direct reporting to the EPA by owners/operators, the following 
paragraphs explain what owners/operators would potentially do to 
support the Agency's need for fuel consumption data.
    The EPA has developed and implemented a point-nonpoint 
reconciliation approach to resolve any double counting of ICI fuel 
combustion sources, but challenges remain. The EPA has refined the 
nonpoint ICI fuel combustion approach for each NEI triennial year, 
resulting in the most recent approach as described in the 2020 NEI 
TSD.\56\ The EPA's revisions to the approach have relied on States' 
comments and concerns as part of each triennial NEI process. Based on 
these activities, the EPA has concluded that to prevent double counting 
of emissions between point and nonpoint ICI sources, the point-nonpoint 
reconciliation must be based on subtracting point source fuel 
consumption from the total fuel consumption within a State. This is in 
contrast with past approaches that allowed subtraction of emissions, 
which has been found to be insufficient because point source emissions 
are often controlled such that subtracting emissions does not remove 
the correct proportion of ICI activity from the nonpoint emissions.
---------------------------------------------------------------------------

    \56\ U.S. EPA, 2020 National Emissions Inventory, Technical 
Support Document, March 2023, EPA Document number EPA-454/R-23-001, 
https://www.epa.gov/air-emissions-inventories/2020-national-emissions-inventory-nei-technical-support-document-tsd.
---------------------------------------------------------------------------

    When States use the approach currently provided, the EPA is 
satisfied that the emissions estimates avoid double counting and 
provide the best available emissions inventory estimates. While the 
nonpoint approach may continue to evolve, the EPA expects that the 
point source fuel use will continue to be a critical part of that 
process. While the current approach is conceptually simple, the EPA has 
concluded that this proposed action should ensure that the EPA and 
States have access to the fuel consumption data from point sources.
    To ensure that the EPA and States have data to support point-
nonpoint reconciliation for ICI fuel combustion, this action proposes 
to require States to collect and report point source fuel consumption 
for certain emissions processes. These proposed changes are reflected 
in the proposed Table 2b to Appendix A of this subpart. It is necessary 
to collect fuel consumption from point sources, because under this 
proposed action, point source data would be reported every year for all 
sources. The annual reporting would allow the EPA and States to 
subtract point source fuel consumption from State total fuel 
consumption irrespective of whether States report nonpoint data on a 
triennial year. The EPA is proposing that fuel consumption totals by 
fuel to be required for all SCCs for a given inventory year that 
reflect any fuel consumed after it has been produced and sold for 
consumption. Thus, any in-process fuel combustion (such as combustion 
of captured process gases) would be exempt from this proposed 
requirement. For triennial years, States would have additional 
requirements for nonpoint sources, which are described in section IV.J 
of this preamble.
    EPA additionally proposes that owners/operators of point sources, 
who are reporting directly to EPA, must include fuel consumption data. 
The EPA has already added this collection approach into the CAERS for 
use by owners/operators. To the extent that States wish to leverage 
this feature of CAERS rather than comply with their fuel use reporting 
requirement a different way, the EPA recommends that States evaluate 
the possibility of using fuel consumption data provided by facilities 
that report using CAERs.
    Depending on States' choices about reporting HAP on behalf of 
owners/operators, the EPA recognizes that the fuel consumption data may 
come from owners/operators for some facilities and processes (i.e., 
those with HAP emissions), but fuel consumption data for other 
facilities and processes may come from States reporting CAP emissions. 
As previously described, this proposed action would not require States 
to participate in CAERS. This flexibility for States could result in 
owners/operators needing to report the fuel consumption both to the EPA 
through CAERS and to the State. To avoid this additional burden on 
owners/operators, the EPA encourages States to participate with CAERS 
in one of the data flows that would avoid duplicative burden on owners/
operators for fuel consumption.
5. New Requirement for Including Title V Permit Identifier
    Title V of the CAA forbids major sources and certain non-major 
sources from operating without a permit. The vast majority of ``title 
V'' operating permits are issued by State or local authorities under 
State rules approved by the EPA to issue such. Title V operating 
permits are required to address all applicable pollution control 
obligations (i.e., applicable requirements) under the SIP or Federal 
implementation plan (FIP), the acid rain program, the air toxics 
program, or other applicable provisions of the CAA (e.g., NSPS 
including solid waste incineration rules). Sources must also submit 
periodic reports to the permitting authority concerning the extent of 
their compliance with permit obligations. The EPA has adopted 
regulations at 40 CFR part 70, which define the minimum elements 
required for State operating permit programs. In certain circumstances, 
the EPA also issues title V permits under 40 CFR part 71, the Federal 
operating permit program.
    The EPA receives copies of permit applications, permits and 
facility annual

[[Page 54169]]

compliance reports and is aware that a great deal of information is 
available from title V operating permits and from the reports that 
result from the monitoring and reporting requirements that the permits 
are required to contain. For the same reason, users of the NEI data 
often seek permitting information about facilities within the NEI. 
States and the EPA have developed repositories of title V permits, with 
much of that information available online. In most cases, perhaps all 
cases, the title V operating permits have a permit identifier that 
allow for distinguishing a permit from other title V operating permits. 
While there is no requirement under 40 CFR part 70 for assigning a 
unique identifier for title V operating permits, federally permitted 
title V sources do have permit identifiers and the EPA is aware that 
most, if not all, State permit programs also use permit identifiers. 
Based on EPA's current information, States often rely on a variety of 
numbers to uniquely identify various versions of a source's title V 
permit, including the title V permit number, an application number, 
project number, and the State's source identifier number. The EPA is 
seeking comment on which unique identifiers it should collect as a 
permit identifier.
    Given the importance of easily associating point sources within the 
NEI with their Title V operating permits, this action proposes to 
require States to report Title V operating permit identifiers for all 
Title V sources that are also point sources as defined by the proposed 
revision to 40 CFR 51.50. Similarly, this action proposes to require 
owners/operators of facilities to report a Title V operating permit 
identifier when they would report annual emissions totals and 
associated data to the EPA under this action. The EPA additionally 
proposes that this requirement would take effect starting with the 2026 
inventory year. Because the definition of point sources in this action 
does not necessarily include all Title V sources, it is possible that 
this action will not collect all Title V operating permit identifiers, 
but the EPA expects most of them to be collected under this proposed 
action based on the proposed point source definition.
6. New Requirement To Use the Best Available Emission Estimation Method
    EPA guidance published in AP-42 has long established a hierarchy of 
information quality on which States and sources should rely to estimate 
emissions. The Introduction to AP-42, Volume I \57\ provides general 
guidance about different ways to estimate emissions from sources. 
Regarding stationary sources, page 1 of the Introduction to AP-42 
describes that ``[d]ata from source-specific emission tests or 
continuous emission monitors are usually preferred for estimating a 
source's emissions because those data provide the best representation 
of the tested source's emissions.'' The document goes on to acknowledge 
on page 1 that such tests may not be available, and that in such cases, 
emissions factors are ``the best or only method available for 
estimating emissions.'' It also describes on page 2, ``because 
emissions factors essentially represent an average of a range of 
emission rates, approximately half of the subject sources will have 
emission rates greater than the emissions factor and the other half 
will have emission rates less than the factor.''
---------------------------------------------------------------------------

    \57\ The Introduction to AP-42, Volume I, Fifth Edition, U.S. 
EPA, January 1995, https://www.epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors.
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    Figure 1 of Introduction to AP-42 provides a hierarchy of emission 
calculation methods whereby the methods near the top of the hierarchy 
are methods with greater accuracy and methods near the bottom would 
generally have lower accuracy. In reference to this figure, the 
Introduction to AP-42 guides those who seek to estimate emissions by 
stating on page 3, ``[s]electing the method to be used to estimate 
source-specific emissions may warrant a case-by-case analysis 
considering the costs and risks in the specific situation.'' In this 
case, the ``cost'' consideration primarily applies to the decision 
about whether to add a CEMS or perform a source test, since the costs 
for simply looking up an emissions factor and applying it in a 
calculation are negligible in comparison to those other measurement 
options. Another cost could be incurred in cases where a new emissions 
estimation method needs to be developed because none are available.
    As described previously, the EPA is interested in obtaining high 
quality emissions data. Regulatory and other decisions are made by the 
EPA based on the data collected by the AERR; however, the current AERR 
requirements are silent on the question of how emissions should be 
calculated. While this lack of specificity provides States and their 
regulated sources flexibility in how emissions estimates are created, 
the current AERR leaves open the possibility that the best available 
emissions estimation approach may not be used in estimating and 
reporting annual emission totals.
    The EPA is considering the advisability of adding requirements for 
emissions testing at facilities for the purpose of improved emissions 
estimates. In addition to a large burden any such requirement would 
impose, the great variability of source types, source sizes, 
pollutants, source measurement methods, and other factors would make 
structuring such a requirement extremely difficult. Many requirements 
on facilities to perform source tests and performance tests for 
compliance purposes already exist. Given these considerations, an 
addition of source testing requirements would likely be too unwieldy to 
be successful.
    Without a requirement for sources to perform additional 
measurements above and beyond what they are currently performing, the 
EPA can still rely on the available data that States and owners/
operators of point sources have to estimate emissions. To ensure the 
highest possible quality data be provided, the EPA proposes to require 
in Sec.  51.5(a) that States and owners/operators of facilities use the 
best available methods to report annual actual emissions. Further, the 
EPA proposes to refer to Figure 1 of the Introduction of AP-42 and 
include the expectation that States and owners/operators of facilities 
should preferentially use available emissions calculation methods at 
the top of the hierarchy over emissions calculation approaches lower in 
the hierarchy. The EPA also proposes that the best available emissions 
estimation method be used both to determine whether emissions exceed 
any proposed reporting threshold and for reporting emissions to the EPA 
when required or voluntarily reported. Finally, paragraph (a) of the 
proposed regulatory text explains that where current guidance materials 
are outdated or are not applicable to sources or source categories, 
owners/operators should develop and document new techniques for 
estimating emissions, which should rely on any available source 
measurements applicable to the emissions source(s). In proposing this 
approach, the EPA is seeking to strike the appropriate balance between 
EPA's need to obtain the best information and the burden that would be 
imposed by requiring additional source testing.
    The CAA delegates responsibility for estimating emissions of CAPs 
to States and requires emission inventories reported by States to be 
``comprehensive, accurate, and current'' in CAA section 172(c)(3). 
Thus, when source tests, performance tests, or

[[Page 54170]]

continuous emissions monitor data are not available, States and owners/
operators of facilities may use available emission rates from EPA 
compilations of emissions factors such as WebFIRE and AP-42 to estimate 
emissions. The EPA proposes a clarification in Sec.  51.5(e) of the 
proposed regulatory text that emissions factors should represent the 
emissions process and controls at the facility.
    The EPA has observed that many States use EPA's emissions factor 
compilations as the primary source of emission rates in their emissions 
data collection tools. For this reason, States sometimes do not report 
emissions from a process that does not have an EPA-provided emissions 
factor. While the EPA strives for a complete compilation of emissions 
factors, the CAA holds the States responsible for providing emission 
inventory data for CAPs. Therefore, States may not claim that emissions 
do not need to be reported simply because an EPA emissions factor is 
not available through EPA's emissions factor compilations.
    Related to the possibility of missing emissions factors or 
calculation methods, the SBAR Panel Report completed for this proposed 
rule included a recommendation that the EPA avoid requiring small 
entities to develop a new emissions estimation method when none 
existed. Small entity representatives who participated in the panel 
process indicated that such efforts are beyond their resources and 
would impose an undue burden on small entities.
    To clarify the expectation of emissions reporting while avoiding 
undue burden on small entities, the EPA proposes to include within 
Sec.  51.5(a) a statement that ``where current guidance materials are 
outdated or are not applicable to sources or source categories, an 
owner/operator (other than a small entity) should develop and document 
new techniques for estimating emissions, which should rely on any 
available source measurements applicable to the emissions sources(s).'' 
States may estimate emissions with other approaches as described above.
    The EPA is responsible for quality assurance of emissions data 
collected from owners/operators. While the requirements described in 
this section should help ensure high quality data is reported, the EPA 
may identify problems with the data as part of quality review. Based on 
this consideration, the EPA is proposing a statement at Sec.  51.25(c) 
that as part of this review, the EPA may require an owner/operator of a 
point source to review and/or revise data that do not meet quality 
assurance criteria. The EPA proposes that it may additionally require 
an owner/operator of a point source to provide other data or 
documentation to support their submissions when information provided 
does not fully explain the source or quality of the data provided.
7. New Requirement To Use Source Test Reports for Emission Rates
    In the case of source test or performance test data being used for 
emissions estimates, the tests that represent the typical operation of 
a source during the year should be used. Fortunately, many source tests 
are designed to measure emissions during typical operations of a 
source. Because of this, the EPA expects that most source tests should 
be relevant for estimation of emissions from the part of a facility 
that has been measured.
    In addition to the use of the best available emission estimation 
method as described above, the EPA proposes requirements specifically 
regarding the use of source test data. The EPA proposes to require at 
Sec.  51.5(c) that owners/operators of point sources that are 
submitting point source emissions data directly to the EPA under this 
subpart must use the most recent source test(s) or CEMS data applicable 
to the operating conditions of the facility during that year to provide 
annual actual emissions. When reporting directly to EPA, owners/
operators should determine which data to include in any averaged 
emission rate used to estimate actual annual emissions. The EPA 
additionally proposes that when an owner/operator has source test or 
monitoring data for a unit, process, or release point that operated 
during the reporting year and the owner/operator does not use that data 
to estimate emissions, the owner/operator would be required to submit a 
justification for that choice for each unit and pollutant for which 
such data are not used to estimate emissions.
    States would not be subject to the requirements for emissions data 
on owners/operators of point sources. To account for this, the EPA 
proposes a related requirement on states in Sec.  51.5(d). The EPA 
proposes that states submitting point source emissions on behalf of 
owners/operators to the EPA under this subpart must ensure that owners/
operators of facilities submitting data to the State take the same 
approaches as described in paragraphs Sec.  51.5(a) through (c) of this 
subpart. If a State submits data for a facility that has not used 
available source test data or continuous monitor data to estimate 
emissions, then the State must submit a justification for that choice 
for each unit and pollutant for which such data are not used to 
estimate emissions. The EPA expects that the justification would be 
collected by the State from owners/operators.
8. New Requirement To Identify Regulations That Apply to a Facility
    The EPA and States have numerous regulations that require owners/
operators to meet various requirements and emissions limits for a wide 
variety of source categories. When the EPA or States issue a permit for 
a facility (e.g., Title V operating permit), the permit includes the 
regulations to which a facility is subject. This existing permitting 
paradigm allows EPA, States, and the public to easily determine the 
regulations that affect a specific facility. However, since these 
permits are primarily on paper or an electronic format such as Portable 
Document Format (PDF), the current permitting approach makes it 
difficult for EPA, States, or the public to determine all the emissions 
units across the U.S. that are affected by a given regulation. With 
this action, the EPA is considering addressing this limitation by 
collecting certain additional data elements from owners/operators and 
States that would link key permit information with facilities and units 
in the emissions inventory.
    An approach to provide such linking would be prudent because the 
EPA routinely needs to identify all the facilities and units that are 
regulated under Federal or State regulations that reduce emissions. For 
example, the EPA needs to identify those facilities and units subject 
to a particular NESHAP so that the EPA can evaluate the residual risk 
associated with the source category or to perform a technology review. 
Likewise, in making estimates of future-year emissions necessary for a 
RIA or proposing solutions to transported emissions, the EPA needs to 
understand which units are subject to state-imposed pollution reduction 
programs that may go beyond EPA requirements as opposed to a State 
implementing a particular EPA requirement. In addition, accurate 
information about how a regulation affects facilities nationwide would 
help the public know more about the ongoing benefits of EPA's 
regulations.
    Using the current approach of paper of PDF permits, the EPA is able 
to identify affected units for selected regulations; however, the EPA 
has found such efforts to be labor intensive, time consuming, and 
subject to error. While some States do have electronic permitting 
systems that reduce these burdens for EPA, the systems are

[[Page 54171]]

typically not designed in a way that meets EPA's needs and even if such 
a design were available, it would cover only those States that provided 
it.
    In addition to the challenges posed by paper/PDF formatting versus 
electronic datasets, the EPA has identified several reasons why the 
current permitting approach is not sufficient for these emissions 
inventory purposes. One reason is that unit identifiers included in 
permits are not always the same as those identifiers used in the 
emissions inventory. Thus, it is not necessarily possible to match the 
unit(s) as identified in a permit with those units and their emissions 
from an inventory. A second reason is that States do not have a uniform 
permitting approach that could allow for automating the scanning of 
paper/PDF documents. One way to eliminate these challenges would be a 
wholesale revamping of permitting that connects permits to emissions 
inventories (as some States have done) and to ensure facility IDs and 
units are synchronized across permitting and emissions inventories. 
However, this sort of endeavor would generate significant burden and 
would affect much more about the permitting process than simply getting 
the data that the EPA needs for inventory purposes.
    To create the data flow needed to address this issue and to 
minimize burden, this action proposes to require certain additional 
data elements for point sources from States and owners/operators of 
point sources. For the major source designation, this action has 
already described a proposed requirement for States and owners/
operators of facilities to provide a title V permit identifier, and 
that requirement would help provide the Major source designation 
information but does not address whether the source is a Major source 
for CAPs, HAP, or both. To allow for full categorization, this action 
proposes to include a reporting requirement in Table 2a to Appendix A 
of this subpart, a Facility Source Category Code. This code would allow 
a facility to be designated as one of the following: CAP major, HAP 
major, HAP and CAP major, HAP, and nonattainment area major, 
nonattainment area major, non-major, or synthetic non-major. The EPA 
additionally proposes that this requirement would not take effect until 
the 2026 inventory year (to be reported by May 31, 2027).
    This action additionally proposes to require States and owners/
operators of point sources with State or Federal operating permits to 
report the regulatory applicability for each unit or process for which 
a federally enforceable regulation applies and is included in EPA's 
list of regulatory codes. Currently the list includes regulations 
within 40 CFR parts 59, 60, 61, 63, and 65. The EPA provides the list 
through the EIS and has included the current list in the EPA docket for 
this action. As described in section IV.A.12 of this preamble, this 
proposed requirement would include an optional accommodation for small 
entities (that meet certain criteria) to require only reporting of 
these additional data elements by unit, even when the regulation 
applies only for a particular process of the unit. The EPA additionally 
proposes that these requirements would not take effect until the 2026 
inventory year (to be reported by May 31, 2027).
    Under this proposed action, States or owners/operators of permitted 
sources would be required to provide the regulatory codes for a unit 
when the entire unit is subject to a particular regulatory requirement 
in EPA's list and would be required (if not a small entity) to provide 
the regulatory codes for a process (e.g., a particular fuel burned at 
that unit) if a single process within a unit is subject to a regulation 
but not the entire unit. This requirement would apply to all facilities 
for which a State/local/tribal CAA permitting authority (including the 
EPA as the permitting authority) has issued a permit for construction 
or for operation.
    If a State or owner/operator provides a regulatory code for a unit 
(rather than a process at that unit), then the EPA would assume that 
regulation applies to all processes at that unit. In addition, the 
required data would include the start-year and any end-year of 
applicability of the regulation to the unit or process. Finally, States 
and owners/operators may optionally include any State regulations 
associated with units and processes. If such optional regulations are 
included, then the State or owner/operator would also need to include a 
description of the State regulation.
    The EPA recognizes that this proposed requirement would impose some 
incremental burden on owners/operators and States. Most of this burden 
would occur in the first year of reporting under the new requirements 
as proposed, and subsequent years would see a decline in that burden 
because only changes to the information would be required to be 
reported, as the EIS and CAERS carries forward data about regulations 
from one year to the next.
9. Existing Regulatory Requirements To Be Required by EPA Data Systems
    The EPA has identified several data fields that are relevant to 
perform its regulatory functions, for which States have not always 
provided complete data. The current AERR requires reporting of design 
capacity and associated data elements like unit of measure for any 
point source combustion units. The current AERR additionally requires 
the throughput that is used to calculate emissions when emissions are 
calculated using emissions factors. EIS does not currently reject 
States' data when it does not include these required data elements. The 
current approach is based on feedback from States offered as part of 
routine collaboration for the NEI in which States indicated that the 
information was not available in their data systems when the EPA 
started using the EIS for the 2008 inventory. After collecting 2008 
inventory data, the EPA observed that some States used default values 
rather than obtain accurate data for these fields. For this reason, the 
EPA stopped requiring those fields so as not to clutter its 
repositories with inaccurate data based on State defaults.
    Accurate information on design capacity and associated fields will 
help the EPA better understand the size of combustion units when 
evaluating alternative regulatory approaches to reducing emissions from 
these sources. Accurate and complete data about throughputs used to 
estimate emissions is critical to include so that the EPA can quality 
assure the resulting emissions data and have all information needed to 
transparently provide the origin of the emissions estimates in the NEI. 
To achieve this, the EPA plans to reject data submitted to EIS that 
does not include the unit design capacity and associated data elements 
required under the current AERR and in this proposed revision to the 
AERR for any combustion unit starting with the 2023 inventory cycle. 
Likewise, the EPA plans to reject data submitted to EIS for emissions 
estimation methods that require throughput to calculate emissions 
(e.g., emissions factors) when the throughput data are not included in 
the submitted emissions reports. The EPA is not reopening these 
requirements included in the current AERR but rather is simply using 
this preamble to explain the Agency's intent to start collecting these 
data once again.

[[Page 54172]]

10. Option for Reporting Two-Dimensional Fugitive Release Points
    The current version of this subpart already allows for States to 
report two-dimensional fugitive release points. These fugitive release 
points can take the form of a series of vents near the top of a 
manufacturing building, whereby any pollutants inside the building can 
be vented to the ambient air. These two-dimensional releases can be 
oriented in any position. The current version of this subpart provides 
that these two-dimensional fugitive release points can be specified 
using a latitude/longitude of the southwest corner of the release, 
width, length, and an orientation angle in degrees from north, measured 
positive in the clockwise direction from the western-most point. The 
definition of the appropriate angle to use has been challenging for 
States to understand and implement.
    Fugitive release parameters are very important because they impact 
modeled risk. Often fugitive releases are lower to the surface and thus 
may pose an increased risk to nearby communities as compared to tall 
stacks that disperse the pollutants before they reach ground level. The 
EPA's review of data from past inventory cycles shows that either 
fugitive releases are not included in State submissions or when 
submitted, the two-dimensional release parameters are incorrect. The 
inaccuracy of these data is a significant reason for adjustments to the 
NEI for use in EPA technology reviews and risk reviews, after the NEI 
has been completed. This additional review takes time and delays 
regulatory actions and consequently delays protection of public health. 
These delays could be avoided if States (and/or owners/operators of 
facilities reporting to EPA) were to submit correct information. To 
address the challenges of the existing angle-based, two-dimensional 
fugitive release points, the EPA is proposing a simpler approach.
    The EPA has devised a new approach that is easier to understand and 
has been previously implemented as part of the RTR program's 
information collections under CAA section 114 and in CAERS. This 
approach relies only on the width of the two-dimensional releases 
(e.g., the building width) and coordinates of the midpoints each end of 
the length of the release. The latitude/longitude coordinates are 
readily obtained through GPS devices on common cell phones, and the 
building width can either be measured or obtained from building plans. 
The greater simplicity of this proposed additional approach suggests 
that it will assist States and owners/operators in complying with the 
provisions of this subpart that include reporting fugitive release 
points and their associated coordinates.
    Based on these considerations, the EPA proposes to allow States and 
owners/operators to use either the existing angle-based approach for 
this current subpart or the new approach as just described. The current 
approach allows for States who have previously collected accurate two-
dimensional release point data to continue to provide that. The new 
approach will help reduce burden, improve compliance with this subpart, 
and improve data quality. It allows reporting the orientation of two-
dimensional fugitive releases by providing the latitudes and longitudes 
for center of the sides of each release. For the example of a 
rectangular building with vents (a common fugitive release), this 
approach would allow a GPS-provided location to be collected by someone 
while standing first at the midpoint of one side of the building, then 
at the midpoint of the opposite side.
    While this action proposes to retain the angle-based approach, the 
EPA continues to consider a second option that would phase-out the 
angle-based approach in the future. This ``Single Fugitive Approach 
Option'' would provide less overall complexity for the data system and 
allow for easier quality control. It also would compel States that may 
incorrectly assume that their data are accurate to regenerate that data 
using the new approach, improving the accuracy of the emissions data. 
If the EPA were to eliminate the angle-based approach from the 
reporting structure, it would consider doing so as early as the 2023 
inventory year (which would be due under this proposal by January 15, 
2025) or as late as the 2032 inventory year (which would be due under 
this proposal by May 31, 2033). The EPA urges commenters to provide 
input on the advisability of retaining the angle-based approach 
indefinitely or phasing it out during the periods suggested.
11. Changes To Reporting the North American Industrial Classification 
System Code
    The current AERR requires that point source reports include a 
single NAICS that applies to a facility. The EPA has observed that 
multiple NAICS may apply to a single facility. To support the interest 
that some States and owners/operators may have in reporting all 
applicable NAICS codes, the EPA has included in its latest reporting 
formats (as included in the docket for this proposal) a capability that 
allows States to report multiple NAICS for the same facility. When 
multiple NAICS are reported voluntarily, States need to provide an 
additional data element to indicate which NAICS is considered the 
primary NAICS and allows for labeling the other NAICS provided as 
secondary, tertiary, etc.
    EPA is proposing to formalize this voluntary approach by including 
an additional NAICS Type data element, and that this data element is 
only required when multiple NAICS are reported. The EPA proposes that 
reporting multiple NAICS and including the NAICS Type data element 
would be voluntary for both States and owners/operators. However, when 
multiple NAICS are voluntarily reported, the NAICS Type data for at 
least one NAICS would be required to indicate the primary NAICS. The 
EPA would assume that any State and owner/operator reporting a single 
NAICS is reporting the primary NAICS.
    With the addition of the concept of primary NAICS, the EPA has 
identified the need to define that term. The EPA considered definitions 
available from the small business administration (13 CFR 127.102), the 
GHGRP (40 CFR 98.3), and the TRI program (40 CFR 372.22). After 
reviewing these available definitions, the EPA is proposing to define 
primary NAICS as ``the NAICS code that most accurately describes the 
facility or supplier's primary product/activity/service. The primary 
product/activity/service is the principal source of revenue for the 
facility or supplier.''
    In addition, the EPA is proposing to specify the number of digits 
for the NAICS value that States and owners/operators must include when 
reporting. The NAICS system allows for NAICS codes from 2-digits to 6-
digits, where more digits provide more specifics about the business 
activity. As previously described in section IV.A.8, the EPA is 
proposing a list of NAICS codes for which facilities with that primary 
NAICS code would report HAP for those emitted pollutants that exceed 
proposed reporting thresholds. This list of NAICS sometimes includes 5- 
and 6-digit NAICS, so it will sometimes be necessary for facilities to 
identify a NAICS at that degree of specificity.
    In its work with States, the EPA has learned that some State 
systems continue to allow facilities to report emissions with only 
Standard Industry Codes (SICs), which OMB replaced for use by Federal 
agencies in 1997.\58\ In 2008, the EPA required that NAICS be used in 
State reports under the AERR

[[Page 54173]]

(73 FR 76539); however, when States collect SIC, they must map it to a 
NAICS code for reporting for this subpart. This mapping can result in 
less specific NAICS. For this and other reasons, some States have been 
unable to report NAICS beyond a 4-digit degree of specificity.
---------------------------------------------------------------------------

    \58\ See U.S. Census, North American Industry Classification 
System, 2023. https://www.census.gov/naics/?99967.
---------------------------------------------------------------------------

    As will be described in section IV.R, the AERR is referenced as 
providing a required data format for numerous SIP inventory 
requirements. Given nearly every State has at some point since 2008 
needed to prepare SIP emissions inventories, the EPA does not know why 
some States do not collect NAICS from their facilities for meeting the 
AERR and SIP inventory reporting requirements. The EPA seeks comment 
from States on what obstacles exist for modernizing their collection. 
Considering that the EPA now provides the CAERS for use by States and 
CAERS includes collection of NAICS, the EPA expects all States should 
update their emissions collections from facilities to meet the AERR 
requirements for NAICS, originally issued in 2008.
    Additionally, the EPA describes in section IV.A.6 its proposal to 
allow States to voluntarily report HAP on behalf of owners/operators, 
which would require States to adopt the same reporting requirements for 
HAP as the EPA has issued in a final AERR rulemaking. If finalized, 
this provision would make collection of NAICS by States essential to 
being able to report on behalf of owners/operators.
    As part of its efforts through CAERS to better share facility data 
across emissions inventory programs, the EPA has evaluated the 
requirements of the TRI, CEDRI, and GHGRP collections and the 
requirement for NAICS. The TRI program requires a 6-digit NAICS code 
(40 CFR 372.85(b)(5)). The CEDRI program does not require NAICS, but 
when it is provided voluntarily, requires that it be provided with 6 
digits. Finally, the GHGRP program requires at 40 CFR 98.3(c)(10) that 
the NAICS be provided ``that most accurately describes the facility or 
supplier's primary product/activity/service.'' The GHGRP has 
implemented this using a 6-digit NAICS requirement.
    Given these considerations, the EPA is proposing to require 6-digit 
NAICS in reports from States and owners/operators under this subpart. 
In many cases, 5-digit NAICS are the same as 6-digit NAICS available by 
appending a zero. In cases where there are more specific 6-digit NAICS 
that correctly describe a facility, then States and owners/operators 
should use it. When a 5-digit NAICS is the best representation of a 
facility, such as when none of the more specific 6-digit NAICS 
correctly describe the primary economic activity at a facility, States 
and owners/operators may instead report a 5-digit NAICS. For those 
owners/operators of facilities also reporting to other programs with a 
6-digit NAICS, the EPA would encourage reporting with the same NAICS 
when appropriate. In addition, a 6-digit NAICS would support 
determination by States and owners/operators whether they are subject 
to reporting requirements if the EPA finalizes the proposal to use 
NAICS as one basis for HAP reporting requirements for non-major 
sources. Further, if the EPA were to finalize the SBA Definition 
Alternative for defining small entities (see section IV.A.14), 6-digits 
would be necessary for implementing NAICS-specific criteria for small 
business definitions. This proposed requirement would also provide the 
EPA more specific information about activities at each facility and 
better standardize the available data to the agency, States, and the 
public.
12. Clarification About Definition of the Facility Latitude/Longitude
    Since the inception of the NEI program, the EPA has observed 
problems with the accuracy of facility locations. In the current AERR, 
Table 2a to Appendix A of this subpart specifies that for point 
sources, States must report ``latitude and longitude at facility 
level.'' However, the AERR provides no definition of this location.
    As described in sections IV.A.11, EPA is additionally proposing 
requirements to collect coordinates for release points, to allow for 
appropriately accurate estimation of cancer risk and other health 
impacts associated with HAP. This ``facility-level'' coordinate serves 
several purposes in implementing the NEI program. First, EPA uses the 
facility-level coordinate to quality assure release point coordinates 
as they are being submitted electronically, to make sure that the 
release point coordinates are within a reasonable distance to the 
facility-level coordinate (EPA has adjusted and may further customize 
these ``reasonable'' distances for each facility to further improve the 
quality assurance). In addition, the single facility-level coordinate 
is used to provide a mapping location of the facility for displaying 
facility-level emissions data for products such as AirToxScreen. Under 
the current AERR, the facility-level coordinates serve as a default 
location for all release points at a facility, and those release point 
locations are used in air quality modeling that supports EPA's NAAQS 
and air toxics programs. Under this proposal, those facility-level 
locations would continue to serve as a default for certain small 
businesses that choose to use the alternative reporting requirements 
available as part of this proposal.
    Many ways exist for interpreting a facility-level coordinate. As a 
result, States provide various interpretations of the location, which 
includes geocoded addresses (which results in a coordinate at the 
roadside) as well as points taken manually from a map. This variability 
is understandable considering the lack of detail in the current rule. 
Without a more specific definition, it is difficult for the EPA to 
obtain quality data to best implement the NEI program.
    The EPA also recognizes that a single facility may have many 
contexts in which a facility-wide coordinate could be used 
appropriately. Thus, the EPA is considering which terms would best 
describe the requirements of this subpart, while also allowing for 
other contexts. Any such term would ideally not conflict with terms 
that may be used to set geocoded addresses or locations in the context 
of regulations related to other environmental mediate (e.g., water and 
solid waste).
    Within the NEI program, the facility coordinates are important for 
two primary reasons: (1) to display the location of the facility on 
maps for end users and (2) to provide a centroid location that defines 
a facility-specific quality assurance perimeter. Using the facility 
coordinates and a facility-specific radius, the EIS can QA release 
point coordinates to ensure that all such coordinates fall within such 
a radius. To address these considerations, the EPA is proposing a 
specific definition of facility coordinates in 40 CFR 51.50 to ensure 
high quality data for mapping purpose and to allow for the effective 
implementation of release point coordinates.
    The proposed definition reads as follows: ``Facility air centroid 
coordinates means a latitude/longitude using the WGS84 or NAD83 datum 
that maps to or near the centroid of the air emissions activities at a 
facility.'' This definition would allow for separation of this 
facility-wide coordinate from other coordinates that currently exist 
outside of the NEI program. In addition to the definition, Table 2a to 
Appendix A of this subpart would be modified to include the term 
``facility air centroid coordinates'' rather than ``latitude and 
longitude at facility level.''
    In addition to defining the term, this proposed change would add 
the specification of which datum should be used when determining 
coordinates to report. In past collections, the EPA has received other 
types of datum without

[[Page 54174]]

specification. The previous AERR did not require specific datum or 
require that a field identifying the datum be included in the report. 
The EPA identified this error in the data after the data had been 
reported, rather than before the data was accepted by the EPA from the 
State. To allow for checking the datum used for the coordinates 
reported, the EPA proposes to add a new required field for States and 
owners/operators to fill in when reporting any coordinates (facility 
air centroid coordinates and release point coordinates).
13. Clarification To Use the Latest Reporting Codes for Electronic 
Reporting
    The EPA has observed that, in past emissions inventory reporting 
cycles, States may try to report their emissions inventory data using 
outdated emissions inventory reporting codes, such as SCCs, unit type 
codes, or control measure codes. When States use outdated codes and 
report to the EIS, the data records using such codes are rejected by 
EIS. If States do not review the EIS feedback report notifying them 
that certain data were rejected, correction of the error(s) is delayed, 
creating unnecessary additional work for both States and EPA.
    To help avoid this problem for States and prevent this problem for 
owners/operators who may be required to report directly to the EPA 
under a final version of this proposed action, the EPA proposes to add 
new requirements about use of the latest EPA codes in submitting 
emissions inventories. The EPA is proposing to add a statement in 40 
CFR 51.5(j) that would require States and owners/operators of point 
sources reporting directly to the EPA under this subpart to use the 
most current data reporting codes for electronic reporting that are 
available at the time of reporting. Reporting codes can change over 
time, and the EPA will strive to publish the reporting codes that can 
be used for each inventory year by June 30th of each inventory year. 
For example, the EPA would plan to publish codes that are to be used 
for reporting 2024 emissions will be published by June 30, 2024. Since 
the proposed regulations would require reporting in accordance with the 
most current codes, entities responsible for reporting should check to 
see if the EPA has published updated reporting codes before they 
report.
14. Clarification About Reporting Individual Pollutants or Pollutant 
Groups
    Some HAP pollutants have different degrees of specificity in how 
they can be reported. For example, mercury could be reported as total 
mercury compounds (i.e., compounds that include mercury but have other 
elements that comprise the compound mass), total mercury (i.e., only 
mercury), or reported separately for elemental gaseous mercury, gaseous 
divalent mercury, and particulate divalent mercury. In proposing the 
addition of HAP reporting to the AERR, the EPA is clarifying in this 
proposed action whether individual pollutants or grouped pollutants 
should be reported.
    EPA has developed experience in collecting HAP information based on 
the existing voluntary HAP reporting from States. As part of this 
voluntary program, the EPA has implemented choices for each case where 
a pollutant group or a specific pollutant could be reported. This 
choice depends on many factors that change over time, including source 
measurement methods, available emissions factors, data system 
capabilities, and QA approaches. To provide a degree of flexibility for 
the data collection approach, the pollutants that are permitted to be 
reported are listed via the EIS for State reporters and via CAERS for 
use by owners/operators. The EPA lists the pollutants that may be 
reported following the reporting codes schedule described in section 
IV.I.13 of this preamble.
    The EPA is proposing that States or owners/operators would be 
required to report the most detailed pollutants possible based on the 
available data (e.g., continuous monitors, source tests, emissions 
factors), so long as the system allows it to be reported. The 
pollutants to be reported may be more detailed than when the pollutant 
group is used to determine if a facility is a point source. For 
example, in section IV.A.4 of this preamble, the EPA proposes that a 
facility could be determined to be a point source when the sum of 
dioxins/furans exceeds a mass-based reporting threshold. The EPA is 
proposing to require the individual congeners of dioxins/furans to be 
reported, in a manner similar to how dioxins/furans are reported to 
TRI, because they have different degrees of toxicity. EPA would use the 
latest available toxicity information to compute the TEQ of the dioxin/
furan group.
    To implement this approach, the EPA proposes to add Sec.  51.5(q) 
to require owners/operators or States reporting on their behalf to 
report the most detailed pollutants available (e.g., the component 
pollutants from Table 1D to Appendix A of this subpart) preferentially 
over pollutant groups. The specific cases listed are polychlorinated 
biphenyls, and mercury. This action further proposes that, when the 
detailed pollutants do not comprise the total mass of the pollutant 
group, owners/operators report the remaining portion of mass for the 
pollutant group. In all cases, owners/operators must only report 
detailed compounds or pollutant groups that are supported by the EPA 
electronic reporting system.
15. Clarification About How To Report HAP That Are Part of Compounds
    For pollutant groups such as ``Lead compounds'' or ``Nickel 
compounds,'' the existing voluntary HAP program has caused confusion 
about how to report such emissions. This confusion stems from the fact 
that the HAP portion of such compounds can be a different amount of 
mass than the total compound, which includes mass of other non-
hazardous elements.
    To avoid further confusion for States or owners/operators who may 
report HAP, this action proposes at Sec.  51.5(p) to require that 
emissions must be reported for the metal portion of the metal group (Pb 
or Nickel in these examples). This proposed approach is consistent with 
the guidance that the EPA has provided to States informally when NEI 
reporting questions have arisen, but this proposed action attempts to 
formalize the approach. If finalized, this proposed action would 
further clarify that no adjustment is needed to estimate the metal 
portion when using emissions factors and source tests, because the 
source measurement methods used to create emissions factors and source 
tests already reflect the metal portion of the compounds. Other 
estimations methods such as material balance or engineering judgement 
may need to include calculations to adjust the mass to reflect just the 
toxic portion of the pollutant group. When no composition information 
is known, the EPA proposes that the entire mass of the material emitted 
be considered and reported as HAP.
16. Requirement To Include Certain Mobile Sources Within Point Source 
Reports
    The EPA has received questions during past NEI years regarding 
whether emissions from mobile sources operating within a facility site 
should be included as emissions from that point source. These mobile 
sources can include mining equipment and other vehicles and have 
emissions both from combustion engines and from road dust

[[Page 54175]]

generated by the vehicles. To resolve any confusion that may exist, the 
EPA proposes to include a statement to clarify that such emissions 
should be included in point source reports.
    The EPA further proposes to define which mobile sources should be 
included to distinguish the mobile sources that are part of the 
functioning of the facility (which would be included) from vehicles 
like cargo trains, employees' personal vehicles, or delivery trucks 
(which would not be included). To accomplish this, the EPA proposes to 
include a statement in 40 CFR 51.5(b) that would require States and 
owners/operators to include in their point source reports the emissions 
from those ``mobile sources (excluding aircraft and ground support 
equipment (GSE)) operating primarily within the facility site 
boundaries of a point source or multiple adjacent point sources''. The 
EPA additionally proposes that this requirement applies when assessing 
whether its facility emissions exceed the emissions reporting 
thresholds in Tables 1A and 1B to Appendix A of this subpart and when 
submitting point source emissions data under this subpart.
    EPA is proposing to exclude aircraft and GSE from 40 CFR 51.5(b) to 
ensure that the section does not conflict with the proposed approach 
for States to report data about aircraft and GSE described in section 
IV.I.1 of this preamble. As previously described, the EPA is proposing 
that for these sources, the EPA would provide LTO data for States to 
review, accept, or provide comments about. Based on the LTO data, the 
EPA would calculate emissions of aircraft and GSE. If those sources 
were to be also included in 40 CFR 51.5(b) to determine point source 
status of a facility, then States and owners/operators would need to 
calculate those emissions independently of EPA. Rather than impose this 
additional burden, the EPA is proposing to exclude those sources from 
point source determinations. Other sources at airports such as 
combustion units and other mobile sources as defined by 40 CFR 51.5(b) 
should be included in making any determination of point source status 
for airports.
    The proposed inclusion of the ``multiple adjacent'' phrase exists 
account for co-located facilities that may share the use of such mobile 
equipment or vehicles. This part of the proposed requirement is 
intended to capture emissions from equipment used in the production and 
operation of a facility, for example, nonroad vehicles and trucks at 
mines, forklifts, and movable electricity generators. The proposed 
requirement is intended to exclude vehicles of employees, temporary or 
occasional on-site contractors (such as temporary construction, 
landscapers, or repair services), and other mobile sources operated in 
many other locations and/or for other purposes.
17. Cross-Program Identifiers Option
    During the SBAR panel, small entities asked about whether the EPA 
would be able to use activity data about industrial throughput that the 
EPA already collects as part of the Toxic Substances Control Act (TSCA) 
section 8. They indicated that that activity data could be especially 
relevant for helping small entities use facility-wide throughputs that 
could be used to estimate emissions using EPA's emissions estimation 
tool (see section IV.A.13 of this preamble). During discussions with 
the panel, the EPA explained that to be able to use such information, 
the EPA would need to be able to match facilities across the NEI and 
TSCA programs. As a result of these discussions, the SBAR panel 
recommended that the EPA take comment on whether small entities would 
prefer to provide the EPA an additional data element with the TSCA 
section 8 facility identifier, so that the EPA could use those 
identifiers to support owners/operators use of the TSCA data, when 
appropriate, for estimating facility-wide emissions. The EPA expects 
that if TSCA identifiers were available, then connections between TSCA 
section 8 data and emissions estimates for AERR could likely be 
included in the emissions estimation tool and/or the CAERS collection 
approach.
    Based on this recommendation and other information included in this 
section, the EPA urges small entities and other commenters to provide 
information about cross-program identifiers. In the case of the TSCA 
section 8 identifiers, the EPA seeks to clarify our current 
understanding that the throughput information from TSCA section 8 may 
not be the relevant throughput for a particular facility, depending on 
the emissions factors and other information available to EPA, to use to 
estimate facility-wide air emissions. In addition, the EPA believes 
that it would be impractical to require reporting of TSCA section 8 
facility IDs only in certain circumstances. Thus, if the EPA 
implemented this approach in any final action, the EPA expects that the 
TSCA section 8 identifier would be an optional data field that could be 
used to help small entities estimate emissions only when provided and 
relevant.
    In addition to TSCA section 8 identifiers, the EPA has many air 
emissions programs with different identifiers from the facility and 
other identifiers that have been collected under the AERR for many 
years and would continue to be collected. Through the CAERS program, 
the EPA has developed a conceptual model of facilities, by which 
emissions from each unit, process, and release point within a facility 
are linked to different air emissions programs. If the detailed data 
reported under the AERR also had cross-program identifiers, then EPA, 
States, and other air emissions data users could better understand the 
relationship among these programs. In some cases, facilities have the 
same definitions across programs and a facility-level cross-program 
identifier is sufficient to map across two programs. In other cases, 
units within a facility as defined by the AERR may be grouped and 
reported as two separate facilities based on the facility definition of 
another program. Similarly, emissions processes (e.g., emissions from a 
primary fuel) might be relevant for reporting separately to one program 
from a different process at the same unit (e.g., emissions from a 
secondary fuel, which happens to be biomass).
    Based on experience with cross-program mapping for air emissions 
programs, the EPA has observed that its attempts to map across programs 
can be error prone. While it is extremely difficult for the EPA to do 
this mapping, the EPA believes that the owners/operators of facilities 
are aware of which units and processes within a facility contribute 
emissions for reporting to each program. Based on discussions with 
owners/operators and States, the EPA is aware that owners/operators 
often estimate emissions at a unit or process level before aggregating 
emissions to a facility level before reporting facility total 
emissions.
    For source test collections involving CEDRI, the EPA is aware that 
owners/operators perform source tests on a specific unit and/or process 
with control devices installed. When reporting these source tests 
however, facilities are not required to use the identifiers that are 
used for reporting emissions under the AERR. If these identifiers were 
used, then EPA, States, and owners/operators could easily map the 
source test data reported to CEDRI to use in calculating emissions when 
it is appropriate to do so. If the EPA had this information from source 
test reports, then it could use it in CAERS to provide the source test 
data to owners/operators using CAERS for calculating their emissions. 
This would lessen burden on owners/operators (and States adopting 
CAERS) to meet the

[[Page 54176]]

proposed requirement to use source test data when it is available. 
Under this scenario, CAERS could link to CEDRI and provide the 
available source test data, and if not selected, require an explanation 
for why it is not suitable as is also proposed to be required by this 
action.
    As mentioned above, the EPA urges commenters to provide information 
regarding the advisability of requiring or optionally allowing cross-
program identifiers, called the ``Cross-Program Identifiers Option'' 
for TSCA section 8, CEDRI, TRI, and GHGRP. If the EPA decided to 
include such a provision in any final action, the EPA would include 
additional data elements in Table 1A to Appendix A of this subpart that 
would allow for owners/operators to report these identifiers. The EPA 
seeks information about the availability of information, the burden 
associated with providing such information, whether cross-program 
identifiers should be required, which programs should be included, and 
what the EPA can do to encourage such reporting, and other ideas for 
using cross-program mapping information to reduce burden on owners/
operators and States.
18. New Requirements When Using Speciation Profiles To Calculate 
Emissions
    One approach for estimation of emissions that may be used when 
other approaches are not available includes speciation profiles. A 
speciation profile is a set of pollutants with associated fractions of 
some other related or ``base'' pollutant. For example, a speciation 
profile could provide a ratio between a benzene and VOC to use to 
estimate emissions of the benzene when a VOC emission value is 
available. If the amount of VOC has been computed for a particular 
source, the fraction of benzene from the speciation profile could be 
multiplied by the mass of the base VOC emissions to calculate benzene. 
This calculation would only be appropriate when the speciation profile 
is relevant for the emissions source. A speciation profile is relevant 
when it has been compiled based on measurements of sources like the one 
for which the speciation profile is being applied.
    Emissions reporting by States under the current AERR allows States 
to use speciation profiles to estimate emissions. Since this approach 
is generally a lower quality method of estimating emissions as compared 
to source tests, emissions factors, or mass balance approaches, 
speciation profiles are typically used only if other sources of data 
are not available.
    To address these considerations, the EPA proposes that a State or 
owner/operator may use the SPECIATE database \59\ or other credible, 
publicly available speciation profile data to calculate ratios of 
related pollutants if relevant speciation profiles are available. In 
addition, to allow the EPA to assess the quality of the information 
provided, the EPA proposes to collect additional information about the 
speciation profile. Specifically, the EPA proposes that starting with 
the 2026 inventory year, when using a speciation profile, a State or 
owner/operator must provide (1) the speciation factor used, (2) the 
SPECIATE profile code when a SPECIATE profile is used or in the case of 
other speciation profiles, the journal citation or reference to a 
publicly available report, and (3) the actual emissions value and all 
relevant required fields (e.g., throughput, emissions factor) used for 
calculating the base pollutant emissions.
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    \59\ SPECIATE Database available at https://www.epa.gov/air-emissions-modeling/speciate.
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    This proposed change would require the emissions value and 
associated required data fields for the base pollutant even if not 
otherwise required by the AERR. For example, some SPECIATE profiles are 
based on total organic gases (TOG), but the current AERR does not 
require TOG reporting. Under this proposed change, however, if a State 
or owner/operator used a TOG-based speciation profile to estimate and 
report emissions, then the State or owner/operator would also need to 
report TOG and the other required elements included in Table 2B to 
Appendix A of this subpart.
19. New Requirement for Small Entity Type
    The EPA has a need to collect and retain information about which 
facilities are owned by small entities and to be able to distinguish 
which small entity definitions apply to a facility. As previously 
described, the EPA expects the proposed revisions to impact small 
entities, and the degree of that impact will depend on the definition 
of small entity that the EPA uses in a final action. Irrespective of 
that definition, the EPA expects States to continue to report emissions 
for whatever businesses State regulations require, including voluntary 
reporting of facilities smaller than the reporting thresholds included 
in this proposal. If these reports included information about which 
facilities are owned or operated by small entities, the EPA recognizes 
that such information would be beneficial for several reasons as 
follows.
    First, generally knowing whether a facility is owned or operated by 
a small entity would allow the EPA to implement different reporting 
options for small entities. Without a facility self-identifying as a 
small entity, the EPA would not be able to provide such options or 
analyze its data to know which facilities that owners/operators have 
reported as a facility total versus which have been reported only a 
single facility, unit, and process. Second, knowing which owners/
operators meet the CAA definition of small entities would support 
implementation of the various expectations of SBEAPs for outreach and 
support of these businesses. Third, knowing which owners/operators meet 
the SBA Definition of small entities would allow the EPA to have more 
information about such entities to more efficiently and effectively 
analyze whether regulations being developed or revised may have a 
significant impact on small entities, as is required by the RFA as 
amended by the SBREFA. Finally, the EPA anticipates interest in 
reviewing the AERR requirements as they apply to small entities in the 
future. For example, the EPA may be expected to assess the utility of 
collecting from small entities. By having this information in the data 
for any small entities reporting under this proposed action, the EPA 
would be able perform any such reviews and assessments.
    Based on these considerations, the EPA proposes to require 
reporting of a Small Entity Type at the facility level starting with 
the 2026 inventory year. This data element would be defined as the 
small entity definitions that apply to an owner/operator responsible 
for reporting emissions for a given facility, and it would be reported 
as an attribute of a facility. We further propose that the available 
types would be ``None'', ``CAA,'' and ``SBA,'' where ``CAA'' refers to 
the definition of CAA section 507(c) and ``SBA'' refers to the 
definition previously described as the SBA Definition Alternative (see 
section IV.A.14 of this preamble).

J. Nonpoint Activity Data Reporting and Nonpoint Survey

    The current AERR requires States to report nonpoint emissions of 
CAPs in triennial years. Nonpoint emissions can be estimated by 
multiplying throughput or activity data (e.g., volume of fuel used) by 
an emissions factor (e.g., quantity of nitrogen dioxide gas produced 
per unit of fuel) to arrive at an emission value (e.g., amount of 
NOX emitting in a year). Nonpoint emissions

[[Page 54177]]

estimates using emissions factors may also be adjusted by a control 
factor when the emissions factor does not already account for emissions 
reductions achieved by owners/operators due to their compliance with 
regulations. More rarely, nonpoint emissions are estimated by 
collecting point source data and summing it across counties to report 
as a county total. In review of the current AERR, the EPA has 
documented some significant reporting gaps that result from the current 
requirements. As described below, the EPA is proposing to retain the 
triennial reporting requirement for nonpoint sources and is proposing 
to make other changes to reduce burden and improve the reporting 
process.
    One key gap is that some States do not submit any nonpoint 
emissions data. As part of the normal collaboration with States for the 
NEI program, some States have explained that they do not have 
sufficient resources to fulfil all AERR the requirements (i.e., lack of 
staff or time). Another gap results when States submit incomplete 
datasets that may exclude whole sectors or parts of sectors. Also, a 
gap is caused when States do supply nonpoint emissions data but have 
calculated emissions using an outdated method, a method that State 
staff cannot explain, or a method without documentation. Another issue 
is not knowing whether the State is using a different SCC or data 
category to report emissions; in other words, some emissions may be 
reported under an SCC that aligns with how the State categorizes a 
sector, but this may not be the same categorization that the EPA uses 
based on documented methods.
    The current AERR does not have a requirement to submit 
documentation of emissions estimation methods alongside the data. Thus, 
when States do submit their emissions estimates, they do not provide 
documentation unless the EPA requests additional information. The 
result can be a lengthy correspondence with State staff to try to 
understand how they estimated emissions. The current AERR includes in 
40 CFR 51.15(c) a provision for the EPA to ask States to voluntarily 
provide supporting information, but the EPA has found this approach to 
be very inefficient. Data quality issues, completeness problems, or 
lack of documentation can be found months after the data have been 
submitted, which has caused the EPA and State to redo work and creates 
delays in completing the emissions inventory. For the 2020 triennial 
inventory year, the EPA has developed enhanced nonpoint QA approaches 
that could further improve quality control of NEI nonpoint sources with 
additional adjustments.
    Since the last AERR revision in 2015, the EPA has observed the 
problems just described in recent NEI cycles. While the EPA provides 
emissions calculation methods with extensive documentation to ensure 
robust methods and reduce State burden, the current AERR process does 
not require use of those emissions methods. Further, when a State has 
emissions calculation methods the State believes represents emissions 
more accurately than EPA's methods, the EPA wants States to report 
emissions totals for nonpoint sources; however, emissions data without 
documentation explaining how it was calculated poses a problem. The EPA 
needs to obtain documentation about those methods to assess State data 
in comparison to the EPA methods and to consider it for possible 
improvements to the EPA methods for future NEI years. Documentation is 
also needed to support transparency of the data and for reproducibility 
for subsequent inventory cycles or release of updated activity to 
improve the estimates.
    Further, both the EPA and States benefit from a process that 
considers the possibility of new information after a State submits and 
other factors. For example, if a State reports emissions and the EPA 
uses that data, the State's calculation method could be superseded by 
improvements in an EPA method. Further, because the EPA uses the NEI to 
estimate future emissions for use in regulatory development, 
documentation of State emissions supports the EPA projecting those 
emissions to the future with full understanding of the origin of those 
data. Without a clear understanding of State methods, it is difficult 
for the EPA to ensure emissions projections are consistent with the 
assumptions a State may make to create their nonpoint emissions 
submission. These considerations support EPA's interest in collecting 
documentation of State emissions calculation methods.
    States continue to experience resource constraints, and any 
approach taken by the EPA should consider that such resource 
constraints could likely continue. At the same time, the nonpoint 
emissions in the NEI are growing in relative importance to other 
sources due to regulations that have significantly reduced point source 
and onroad mobile source emissions over the past 20 years. This is 
illustrated by research in Los Angeles County, CA, where VOC emissions 
(among other pollutants) are important precursors to ozone and 
PM2.5 formation. In Los Angeles, mobile-source VOC emissions 
have decreased, but emissions from pesticides, coatings, printing inks, 
adhesives, cleaning agents, and personal care products have decreased 
less, or in some cases, have increased. In addition, recent studies 
have shown that the chemical components of the VOC emissions from these 
and other nonpoint categories can have an outsized influence on both 
ozone and secondary PM2.5 formation. As a result, nonpoint 
VOC sources have been identified as an increasingly important area of 
study for contribution to public health harms.\60\ Thus, any adjustment 
to the AERR for nonpoint sources should support States without 
sufficient resources as well as promote high-quality and well 
documented data collection.
---------------------------------------------------------------------------

    \60\ McDonald et al. (2018), https://www.science.org/doi/10.1126/science.aaq0524.
---------------------------------------------------------------------------

    Through EPA's work with States, the EPA has continued to refine and 
publish new nonpoint emissions methods and tools for use by the EPA and 
States. The EPA provides States with extensive opportunities to give 
input on the nonpoint emissions methods and incorporates state-provided 
emissions factors and ideas. As a result of this work and State input, 
the EPA has developed a nonpoint estimation tool called the Wagon Wheel 
(WW) as described most recently by the 2020 NEI TSD. The WW Tool 
provides a central hub of the activity data inputs for estimation of 
emissions for many nonpoint sectors. It also provides templates for 
States to submit input activity data and estimation tool assumption 
parameters, and it calculates emissions using county-specific data and 
the latest emissions calculation methods. Under the current AERR, 
States have been using the WW Tool (and its predecessors) voluntarily 
because it reduces the burden of devising their own calculation 
methods, tools, and submitting the emissions data to EIS.
    The EPA and States have also worked together to create other tools 
and approaches (e.g., spreadsheets). Primary among these is the oil and 
gas tool, which the EPA has revised each triennial inventory year since 
2011. States and other stakeholders work closely with the EPA and 
provide comments and input data to improve calculation approaches.
    When EPA's tools are used by States, this provides a consistent, 
documented approach. Also, the burden on States who do not have the 
resources to develop their own tools is greatly reduced with the WW 
Tool and other EPA tools. Using these tools reduces the reporting 
burden on States because the

[[Page 54178]]

process collects activity data in simpler formats (e.g., text, comma-
separated value) than the XML formats required when States report 
emissions to EIS. In addition, when States provide activity data, the 
States can upload this directly to the WW Tool to obtain updated 
emission estimates and provide updated activity data to the EPA to 
ensure more expedient error corrections in emissions estimates when the 
EPA reruns these emissions calculation tools.
    Sometimes States are ahead of the EPA regarding the latest 
emissions from certain nonpoint sectors, or the EPA tools do not yet 
meet a State's needs. For example, some States are not yet able to use 
the Oil and Gas Tool to estimate emissions from that sector while other 
States do not believe that the WW Tool represents their residential 
wood combustion emissions properly. The EPA has observed over the years 
while collecting data for past inventories that there are cases where 
States have better local input data and/or emissions calculation 
methods for sectors that the EPA does not yet have tools for, or others 
in which EPA's tools are not as appropriate for estimates in the State 
as the State's own tools. For example, in past inventory years, States 
have submitted emissions for such categories as cigarette smoke, human 
perspiration, and industrial composting. In these situations, it is 
appropriate for States to provide emissions totals. However, the EPA 
must still be able to access documentation about emissions submissions.
    In addition to the WW Tool, input templates, and other calculation 
tools, the EPA has implemented and used for the 2017 and 2020 triennial 
years an online nonpoint survey as part of NEI collection, as most 
recently explain in the 2020 NEI Plan.\61\ This ``Nonpoint Survey'' 
allows States to indicate their plans for nonpoint sources so that 
States can communicate their intentions for accepting EPA data or 
reporting their own data. This survey greatly assists States and the 
EPA in QA to compare what States submitted to what they intended and to 
allow States to accept EPA estimates.
---------------------------------------------------------------------------

    \61\ 2020 NEI Plan, August 2020, U.S. EPA, https://www.epa.gov/air-emissions-inventories/2020-national-emissions-inventory-nei-plan.
---------------------------------------------------------------------------

    As explained in the TSD, the EPA identified about 53,000 instances 
for which State emissions data submissions for the 2017 triennial 
inventory were inconsistent with EPA's expectations and were, 
therefore, removed from the inventory. In these cases, the EPA needed 
to use its own estimates from the WW Tool and other tools instead of 
relying on state-submitted data. The EPA also prefers to use EPA 
methods because of the consistency and transparency that approach 
provides but wants to make sure that those methods best represent State 
activity inputs. An improved process would both recognize the lack of 
State reporting in many cases as well as steer towards a consistent and 
transparent approach. Any such process might also allow for the case 
where States want the EPA to consider their emissions totals even when 
the calculation method is different from EPA methods and when the State 
is obligated to report emissions that are not estimated by the 
available EPA tools.
    Based on these considerations, the EPA proposes to include a 
requirement at Sec.  51.15(d)(2) for States to complete and submit an 
online survey (the ``nonpoint survey'') to indicate for which nonpoint 
sources States intend to: (1) report input data for tools, (2) accept 
EPA input data, (3) report emissions data, and (4) notify the EPA 
whether or not to supplement data because the emissions are covered by 
a different submitted SCC, the State does not have a particular source, 
or the source is included in a point inventory submission. The EPA 
further proposes at Sec.  51.15(d)(3)(i) that for nonpoint sources, 
excluding commercial marine vessels and locomotives, States would be 
required to report input data for EPA nonpoint tools using the formats 
provided by EPA. In lieu of reporting tool inputs, the EPA proposes at 
Sec.  51.15(d)(3)(ii) to allow States to comply with this requirement 
by reviewing and accepting EPA-provided nonpoint tool inputs.
    For nonpoint sources with EPA tools excluding commercial marine 
vessels and locomotives, the EPA additionally proposes to add an option 
at Sec.  51.15(d)(3)(iii) that would allow States to optionally report 
emissions of any pollutants allowed by the EPA electronic reporting 
system and would require States to provide documentation that describes 
how the emissions estimates were made and QA steps performed. The EPA 
intends to evaluate the documentation provided to determine the best 
approach for ensuring complete data from nonpoint sources that uses 
sufficiently robust and transparent approaches. If documentation were 
to be insufficient or approaches of lower quality than the EPA provided 
approach, then some state-submitted nonpoint data may not be used.
    The EPA additionally proposes provisions for commercial marine and 
locomotive sources. These requirements differ from those of other 
nonpoint sources because of processes available to the Agency. In the 
case of commercial marine vessels, the EPA processes satellite-based 
data available from the Automatic Identification System (AIS), which is 
an automatic tracking system that uses transceivers on ships. In the 
case of locomotives, section IV.I.2 of this preamble describes that the 
EPA works with rail companies to collect the data about locomotive 
activity that is also connected to rail yard emissions. To accommodate 
these special cases, the EPA proposes to add a requirement in Sec.  
51.15(d)(4) that States must either (1) report annual actual emissions 
of required pollutants, (2) provide comment on EPA-provided annual 
actual emissions data, or (3) accept EPA-provided emissions data.
    In addition to those sectors for which the EPA provides tools, the 
AERR must reflect all nonpoint sources for CAPs to support the need for 
comprehensive emissions estimates. To address this need, the EPA 
additionally proposes to add a requirement in Sec.  51.15(d)(5) that, 
for nonpoint sources without EPA tools, States must report emissions 
and documentation that describes how the emissions estimates were made 
and QA steps performed. This proposed requirement would apply for any 
additional sources not reported under Sec.  51.15(d)(3) or (4) of the 
proposed regulatory text, not episodic windblown dust as described 
under Sec.  51.15(d)(7) of the proposed regulatory text, and not such a 
small source that it meets a de minimus standard described under Sec.  
51.15(d)(8) of the proposed regulatory text. Paragraphs (7) and (8) 
would be moved from the current AERR Sec.  51.20(d) to these new 
paragraphs. The EPA intends to evaluate the documentation provided to 
determine the best approach for ensuring complete data from nonpoint 
sources that uses sufficiently robust and transparent approaches. If 
documentation were to be insufficient, then some state-submitted 
nonpoint data may not be used.
    The EPA has revised the windblown dust exemption from the current 
AERR at 40 CFR 51.20(d) which states, ``[e]pisodic wind-generated 
particulate matter (PM) emissions from sources that are not major 
sources may be excluded, for example dust lifted by high winds from 
natural or tilled soil.'' The EPA proposes at Sec.  51.15(d)(7) to 
retain this exemption but remove the limitation of ``PM emissions'' 
from the exemption. The EPA proposes this change because the EPA does 
not need to receive any emissions information about windblown dust, 
which would also exclude HAP. While the EPA is not proposing to

[[Page 54179]]

require HAP from nonpoint sources for other categories, the EPA also 
prefers States not to voluntarily report HAP from windblown dust 
currently.
    In general, the goal of the documentation will be to replicate the 
key information provided in the Nonpoint Emissions Method and Operation 
(NEMO) documents. In some cases that type of documentation would not be 
relevant because a State nonpoint estimate could be summed from data 
collected from individual facilities. To define documentation to be 
reported by States, the EPA would require different information in each 
of these cases. For the general case of nonpoint emissions computed as 
a county total, the EPA proposes that for each SCC and pollutant, the 
State would need to provide any equations used to compute emissions, 
all input values used for those equations, and all references for those 
input values (e.g., government agency websites or publications). These 
input values would need to include activity data, emissions factors, 
and any other parameters of the equations.
    In the case of documentation needed when States provide nonpoint 
emissions as a summed value from facilities, the EPA proposes to 
require States to provide a spreadsheet that contains for each 
facility: the State's facility identifier, a facility name, a facility 
address, a primary NAICS code, the nonpoint SCC to which the emissions 
were mapped, the facility emissions for each pollutant, the emissions 
factor used to compute those emissions (when applicable), any control 
measure applied to the emissions factor, and the type of control (using 
EIS control measure codes). The EPA would provide a template for that 
information for States to use, but States would be free to provide such 
information in other formats.
    In cases where a State is both required to report input data for 
EPA tools and voluntarily submits emissions data, the State burden 
would be higher than under the current AERR. The EPA is considering 
requiring documentation even though the trigger for that requirement is 
a voluntary reporting of emissions by a State. The EPA is proposing 
that such additional burden is warranted for the following reasons. 
First, a State may believe its emissions estimates to be preferable to 
EPA-methods, but the EPA must decide that issue on the merits of the 
method documentation provided by the State. Second, the EPA would use 
the required state-provided tool input data to be able to make a fair 
comparison of EPA's method emissions totals compared to the state-
provided emissions totals. Third, the completion of the Nonpoint Survey 
would remove confusion from differing SCCs, meaning potential 
differences in State and EPA categorization of specific sectors could 
be noted and resolved. Fourth, through discussions with States in past 
NEI efforts, the EPA realizes that States may not be familiar with the 
latest approaches and choose to report emissions even if they are 
unable to find the underlying data that would be needed for complete 
transparency. Finally, if the State later realizes that its provided 
emissions totals are in error, or if the EPA revises its calculation 
method to further improve the emissions estimations in a way the State 
prefers, then the EPA would already have in hand the necessary EPA tool 
input data to calculate emissions for the State.
    The EPA will QA all state-submitted input data and emissions with 
associated documentation. Quality assurance will focus on the resulting 
state-submitted emission estimates compared to EPA input data/methods, 
if available, and previous state-submitted data, checking for data 
completeness for pollutants and geographic coverage, and magnitude. The 
EPA may not use state-submitted input data and/or emissions if it does 
not pass QA checks, so the EPA can comply with the OAQPS Quality 
Management Plan.\62\ Therefore, the EPA proposes to add paragraph Sec.  
51.15(l) stating that the EPA may elect not to use the state-provided 
data if it does not pass QA or if a State's documentation does not 
adequately explain the origin and quality of the submitted data.
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    \62\ U.S. EPA, Office of Air Quality Planning and Standards 
Quality Management Plan, May 20, 2020, https://www.epa.gov/sites/default/files/2021-05/documents/final_oapqs_qmp_2020-05-20.pdf.
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K. Nonpoint Year-Specific Data and Timing of Reporting

    One key goal for the NEI program is to ensure emissions are 
accurately reported for the year of the inventory, and an important 
question for how to achieve that goal is when the submissions should be 
due. This section discusses the considerations and EPA's proposal for 
the timing of AERR submissions.
    Part of ensuring accurate nonpoint emissions is point-nonpoint 
reconciliation as previously explained in section IV.I.4, which 
prevents double counting and can be done with appropriate accuracy only 
when nonpoint activity data are specific to the inventory year. 
Furthermore, because the NEI is used as a starting point for SIPs that 
require the use of ``accurate'' data (see CAA section 172(c)(3)), the 
NEI program goal is consistent with that requirement and the 
expectation of data users that the emissions reflect the listed year of 
the inventory. Finally, when the EPA uses the NEI for regulatory 
actions, it is appropriate for the EPA to follow the Agency's guidance 
on inventories that emissions reflect the year in which they occurred 
as best as possible. For these reasons, this action considers how best 
to achieve year-specific nonpoint emissions inventories.
    On the issue of triennial versus annual reporting, the EPA intends 
to retain the current triennial nonpoint reporting approach for 
nonpoint sources. The EPA is not yet ready to support annual reporting 
for nonpoint sources but may be able to do so in the future (in which 
case we may conduct further rulemaking to require more frequent 
reporting for nonpoint sources). Additionally, the EPA has successfully 
used the data from States during triennial years, EPA tools, and data 
collected from other Federal agencies to estimate emissions on years 
other than triennial years. By retaining triennial nonpoint reporting, 
the EPA additionally would not increase burden on States.
    The current AERR requires that, for each triennial inventory year, 
States must report nonpoint emissions by December 31 of the following 
year. As described in section IV.J of this preamble, this action 
proposes to change the nonpoint requirement such that a State would: 
(1) complete a nonpoint survey, (2) provide inputs for sources where 
EPA tools are available, and (3) report emissions for other nonpoint 
sources without EPA tools. As also described above, States may (4) 
voluntarily report emissions for sources with EPA tools and (5) when 
emissions data are provided, the State must also include documentation. 
This section proposes when each of these required and optional 
submissions would be due.
    In addition to collection of data, the EPA collaborates on a 
continuous basis with States to improve nonpoint emissions calculation 
tools. Based on input from States, peer reviewed literature, and EPA 
research, the EPA develops NEMO documents for comment by States.\63\ 
States can voluntarily comment on these documents over some review 
period provided by EPA. This work can be done independently of any 
annual

[[Page 54180]]

reporting NEI cycle, but in many cases, new methods are developed in 
time for their inclusion in a particular inventory reporting year. The 
EPA has monthly webinars with States to provide many updates including 
the review and discussion of NEMO documents and new methods.
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    \63\ The EPA has provided the most recent NEMO documents with 
the release of its 2017 NEI. These documents are available on the 
EPA website at https://gaftp.epa.gov/air/nei/2017/doc/supporting_data/nonpoint/.
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    Nonpoint emissions calculation methods rely on activity data from 
other Federal agencies and other sources, and these data are released 
after the current AERR deadline for nonpoint sources. For example, the 
U.S. Census County Business Patterns dataset is important for nonpoint 
calculations, but it is released approximately in April, about 16 
months after the end of the inventory year. In the current AERR, States 
must report emissions data 12 months after the end of the inventory 
year and, thus, would need to use county business pattern data from the 
prior year to estimate emissions.
    While using input data for a different year may be acceptable for 
some sectors where the input data does not change much, other nonpoint 
sectors can have significant local and national changes in emissions 
from year to year (e.g., oil & gas exploration and extraction, 
residential wood combustion). These sectors vary greatly depending on 
unpredictable economic, weather, and other unexpected events. To 
address this year-specific importance for some nonpoint categories and 
the challenges caused by the current deadlines, the EPA is proposing 
changes to the timing of nonpoint requirements.
    Another factor to consider is a current AERR provision that 
undermines the argument for using year-specific data. Within the 
current AERR, Sec.  51.35 provides States directions regarding how to 
equalize the emission inventory effort from year to year, since a 
triennial inventory means more effort on every third year. This section 
explains that States may ease the workload spike by collecting one 
third of their point sources that are not reported every year (i.e., 
the sources that are Type B but not Type A) and collect data for one-
third of the nonpoint, nonroad mobile, and onroad mobile sources. This 
section further explains that States must use a consistent approach 
between the 3 years for whatever source category is collected over 3 
years. This section of the current AERR provides a burden equalization 
approach for States but does not reflect the points made above about 
the importance of year-specific inventories.
    In section IV.G of this preamble, the EPA proposes to require 
States and owners/operators to use the same criteria each year to 
determine which point sources should report. This provision would make 
the current Sec.  51.35 ``burden equalization'' approach irrelevant for 
point sources. In addition, this section has described the importance 
of having year-specific data for nonpoint sources in some cases. At the 
time that Sec.  51.35 was originally published, the EPA had a much less 
robust support system to help States estimate emissions from nonpoint 
sources. Now, many tools are available for States to estimate nonpoint 
emissions, and it is important that States all use current methods to 
do so. With the ongoing development of emissions methods by EPA, 
allowing a State to make estimates based on an old methodology 2 years 
before the data are due does not promote the data quality needed for 
the NEI.
    Additionally, the EPA has realized that, even with this burden 
reduction approach available to States, many States have not met their 
nonpoint source reporting requirements in recent past NEI years. As a 
result, the EPA has described in section IV.J of this preamble how 
States would be able to comply with this proposed action simply by 
reviewing and accepting EPA-provided activity data. Further, under this 
proposed action, States would be required to use the emissions 
calculation methods provided by the WW Tool. None of these provisions 
would be workable under the current provisions of Sec.  51.35. As a 
result of these considerations and in addition to the reasons described 
in section IV.G of this preamble, the EPA proposes to remove the 
equalization provisions of Sec.  51.35 and add a new set of timing 
requirements that would allow the EPA to obtain appropriate, year-
specific data as needed while still including provisions that spreads 
out the work for States.
    As previously described, nonpoint tool inputs can become available 
after the current AERR reporting deadline. Depending on the data, they 
are available to the EPA and States starting approximately 6 months 
after the end of an inventory year (e.g., June of 2024 for the 2023 
inventory year) through October of the second year (e.g., October of 
2025 for the 2023 inventory year). As a result, the EPA targets March 
of the third year after the inventory year for the final NEI nonpoint 
data (e.g., March 2026 for the 2023 inventory year). Since the EPA does 
not control the timing of release of that data, the EPA also recognizes 
the importance of building flexibility into the process.
    Based on these considerations, the EPA proposes several changes to 
the timing of the nonpoint collection. First, this action proposes that 
States would complete the nonpoint survey in EIS by 15 months after 
each triennial inventory year (e.g., March 31, 2025, for the 2023 
inventory year). In addition, for any emissions sources without an EPA 
tool, but not meeting the de minimis criteria included in this proposed 
action, the State would report emissions and documentation by March 31, 
15 months after a triennial inventory year. These deadlines and others 
are summarized below in section IV.S of this preamble.
    Second, the EPA proposes to spread out requirements for submission 
of input data for EPA tools, including the option to review and accept 
EPA tool inputs. The EPA expects to release draft tool inputs and 
emissions results on an incremental basis between July after the 
inventory year (e.g., starting July of 2024 for the 2023 inventory 
year) and December of the second year after the inventory year (e.g., 
through December 2025 for the 2023 inventory year). The EPA proposes to 
add regulatory text stating that the States would have no fewer than 30 
days to review, comment, and/or provide revised tool inputs based on 
the information released by EPA, and that the EPA may allow a longer 
period for review source categories with more complicated input data or 
calculation approaches and would notify the States of this when the 
data are released. To communicate a longer period, the EPA proposes to 
indicate the period for review to States at the time the data are 
provided for review. The EPA intends to include this information in its 
periodic NEI newsletters included on the NEI Sharepoint site.
    After receiving the emissions based on EPA methods, States may 
determine that the EPA tool calculation is insufficient. In this case, 
the EPA proposes to add regulatory text stating that the States would 
submit nonpoint tool inputs within 30 days of the EPA providing tool 
inputs to the State, or within the period defined by the EPA at the 
time the tool inputs are provided to States, whichever is longer. For 
example, if the EPA released tool input data and draft emissions on 
August 1 for State review with a 30-day review period (until August 
31), States would have until September 30 to review/submit revised tool 
inputs. Additionally, the EPA proposes to add regulatory text that 
would set a timeline for States optionally submitting emissions and the 
associated documentation within 60 days of the EPA providing inputs to 
the State, or within the period defined by the EPA at the time the tool 
inputs are provided, whichever is longer.
    In addition to collection of tool inputs, a key aspect of nonpoint

[[Page 54181]]

emissions work with States is the emissions calculation approach, 
captured in the NEMO documents. While the EPA does not plan to require 
States to contribute to these documents at this time, it anticipates 
that many States will continue to do so voluntarily. To accommodate 
this voluntary State collaboration, each NEI Plan gives States 
timeframes during which they may provide these voluntary comments so 
that the emission methods would be ready for use in a triennial 
inventory. In cases where a State misses these deadlines, the Agency is 
under no obligation to consider late-filed State comments but rather 
intends to defer consideration of such late comments into the method 
improvements that would be done for the next triennial inventory cycle.
    Under this proposal, the bulk of State's burden for nonpoint 
submitting data would occur in the starting 6 months after the 
triennial inventory year and continuing through the second year after 
the triennial inventory year. Given this timing, the EPA plans to 
coordinate the timing of the voluntary State review of emissions 
methods so that States' work would be done primarily during periods the 
EPA has proposed to require triennial nonpoint emissions data. For 
example, for 2023 (the next triennial inventory year), the EPA would 
plan to support voluntary comments from States on methods between 
January 2023 and June 2024.

L. Nonpoint Reporting for Tribes and States With Counties Overlapping 
Indian Country

    With this action, the EPA is proposing new requirements that would 
resolve existing challenges associated with use of nonpoint emissions 
submitted by tribes and prevent double counting with state-submitted 
county total emissions. The EPA and States estimate nonpoint emissions 
data with techniques that use county total activity data from other 
agencies such as the U.S. Census Bureau. There are two cases that can 
cause the potential for double counting without the approach that the 
EPA proposes in this action.
    In the simplest case, EPA's nonpoint emissions tools multiply 
county total activity data with emissions factors to estimate 
emissions. When counties overlap with Indian country, the tools do not 
automatically account for the portion of the county that is within 
Indian country. When States report emissions for areas overlapping an 
area reported by a tribe, the NEI could potentially double count 
emissions unless those reporters take additional steps to adjust the 
activity data prior to calculating emissions.
    The second case can occur when States accept emissions from EPA's 
tools. In these cases, because EPA's tools include activity for the 
entire county, double counting would occur when a tribe reports 
nonpoint emissions data for Indian country overlapping those counties 
using EPA's estimates. Further, the current AERR does not require 
activity data for nonpoint categories from tribes that could be used to 
subtract from the counties' data to avoid double counting. As a result 
of this complexity, to date the EPA has chosen to use only the State 
provided nonpoint data when using the NEI as an input for air quality 
modeling. The EPA prefers and considers it more equitable for tribes to 
be able to have tribal data used in the same ways as State data.
    The current AERR at 40 CFR 51.1 says that ``[s]tates must inventory 
emission sources located on nontribal lands and report this information 
to EPA.'' This is the only reference under the current AERR to the 
concept of excluding Indian country from emissions estimates. Further, 
this statement is confusing because, as explained in the preamble to 
the original AERR (71 FR 69), the term ``states'' is defined in the 
AERR as referring to States, locals, or tribes with a TAS agreement. 
The EPA is proposing at Sec.  51.1(b) language that describes the 
specific situation in which an Indian Tribe would be required to report 
under Subpart A of 40 CFR part 51.
    In addition to the potential confusion created by the current text 
of Sec.  51.1, other parts of the current AERR could be read to be 
inconsistent with Sec.  51.1. First in Sec.  51.25, entitled ``What 
geographic area must my state's inventory cover?'', the current AERR 
makes no mention of Indian country but rather says ``because of the 
regional nature of these pollutants, your State's inventory must be 
statewide, regardless of any area's attainment status.'' ``Statewide'' 
could potentially be read as inclusive of Indian country. In addition, 
the current version of Sec.  51.15(b)(2) explains that for nonpoint 
submissions, ``states may choose to meet the requirements for some of 
their nonpoint sources by accepting EPA's estimates for the sources for 
which the EPA makes calculations.'' Given that EPA calculations have 
not excluded (and are not planned to exclude) Indian country emissions 
from the emissions that States report, this statement neglects to 
clarify that a State would need to make an adjustment based on the 
requirement to exclude Indian country as specified in the current AERR 
at Sec.  51.1. As a result of these potentially confusing requirements, 
the approach taken by States has been inconsistent in submitting 
emissions data. Under the current AERR, some States exclude Indian 
country emissions from their emissions while others do not.
    With this action, the EPA proposes an updated reporting approach 
for nonpoint sources with EPA tools such that all agencies (including 
tribes with TAS status) would report tool inputs, including activity 
data. For those tribes that would report nonpoint activity data, the 
EPA would need to have sufficient information from tribes to be able to 
reconcile the county-total activity with the tribal activity to avoid 
double counting.
    Based on these considerations, the EPA is proposing several 
revisions intended to ensure clarity for States and tribes. First, the 
EPA proposes to add paragraph (b) to Sec.  51.1 to clarify that tribes 
that have obtained TAS status are subject to the AERR to the extent 
allowed in their TIP, and that, to the extent a tribal government has 
applied for and received TAS status for air quality control purposes 
and is subject to the AERR under its TIP, the use of the term ``state'' 
in the AERR should be read to include that tribal government.
    Additionally, the EPA proposes additional nonpoint requirements to 
address the issues described in this section. Taken together, these 
requirements will allow both State/local and tribal nonpoint tool 
inputs and emissions to avoid double counting and to be used as inputs 
to air quality modeling. First, the EPA proposes at Sec.  51.15(d)(9) 
of the proposed regulatory text that a State with counties that overlap 
Indian country would avoid double counting by excluding the activity 
and/or emissions associated with Indian country when the Tribe is 
expected to report emissions. A State would need to become familiar 
with which of the tribes with Indian country that overlaps a State's 
counties would be required to report under this proposed action and 
which tribes intend to voluntarily report. Similarly, tribes can assist 
in preventing double counting by notifying States of their plans to 
submit emissions (though the EPA is not proposing that tribes would be 
required to do so).
    Second, the EPA proposes at Sec.  51.15(d)(10) of the proposed 
regulatory text that tribes meeting the TAS and TIP criteria of the new 
Sec.  51.1(b) of the proposed regulatory text would be required to 
report nonpoint tool inputs or emissions from Indian country by 
reporting those data separately for each portion of a county across 
which Indian

[[Page 54182]]

country boundaries overlap. To assist tribes in making such 
calculations, the EPA could provide tribes with ratios that they may 
use for performing these calculations. A tribe meeting the criteria of 
the proposed Sec.  51.1(b) would be subject to the nonpoint reporting 
requirements associated with the new Sec.  51.15(d)(3) through (8) of 
the proposed regulatory text when the tribe has sources that meet the 
criteria for reporting a nonpoint source (i.e., sources that have the 
EPA nonpoint tools or are not small enough to meet a de minimus 
percentage of the tribe total emissions). The EPA believes that tribes 
could use the EPA tools by adjusting the county values included in the 
default templates to provide tribe-specific activity levels. Similarly, 
tribes submitting emissions would report those data in association with 
county boundaries by apportioning the total tribal emissions to each of 
the county areas overlapping Indian country.

M. Requirements for Prescribed Burning

    Recent increases in the frequency of damaging wildfire events 
underscore the need for improved management schemes that anticipate and 
consider climate change factors like drought and temperature extremes. 
Prescribed burning (of forestland, shrubland, grassland, wetlands, 
wildland urban interfaces (WUIs), and timberland) \64\ is a way to 
prepare for and mitigate wildfire events and manage grasslands, and 
many States \65\ have implemented burning programs to improve ecosystem 
health and reduce chances of catastrophic wildfires. The U.S. 
Department of Agriculture Forest Service (USFS) Wildfire Crisis 
Strategy,\66\ published in January 2022, indicates an interest in 
increasing prescribed burning to treat up to an additional 20 million 
acres on National Forest System lands and up to an additional 30 
million acres of other Federal, State, Tribal, and private lands.\67\ 
While these prescribed burns are controlled and limit emissions as 
compared to wildfires, they still produce significant emissions of CAPs 
such as PM, VOC, HAP, and carbon dioxide, all of which are important 
contributors to environmental health risks and climate change. The EPA 
proposes additional requirements for States to report prescribed 
burning data and consequently allow the EPA to have access to improved 
data sources as compared to the data it has been collecting voluntarily 
under the current AERR.
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    \64\ In this section, the use of the term ``prescribed fire'' 
and ``prescribed burning'' refers to burns that could occur on all 
of these land types, unless otherwise specified.
    \65\ In Section III of this preamble, the EPA has previously 
defined ``States'' to mean delegated local agencies and certain 
tribes.
    \66\ U.S. Department of Agriculture, Forest Service, Confronting 
the Wildfire Crisis: A Strategy for Protecting Communities and 
Improving Resilience in America's Forests, January 2022. See also 
https://www.fs.usda.gov/sites/default/files/Confronting-Wildfire-Crisis.pdf.
    \67\ U.S. Department of the Interior, ``Infrastructure 
Investment and Jobs Act, Wildfire Risk Five-Year Monitoring, 
Maintenance and Treatment Plan,'' April 2022. See also https://www.doi.gov/sites/doi.gov/files/bil-5-year-wildfire-risk-mmt-plan.04.2022.owf_.final_.pdf.
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    The EPA currently uses satellite data to identify the locations of 
fires and uses various techniques and data from other agencies to label 
fires as wildfires, prescribed fires, or agricultural fires. The EPA 
has a goal of improving emissions estimates for all types of fires, and 
this proposal strikes a balance between the information proposed to be 
required and the burden that will be incurred by the many States that 
will need to implement new data collection programs. The EPA's 
experience over the past decade has determined that without more data, 
it is not possible to accurately differentiate prescribed burning from 
other types of fires in most States. The satellite data provide 
estimates of the extent of burning each day but, in many cases, the EPA 
must assume information about the type of fire, the biomass fuel type, 
the amount of biomass consumed and other critical parameters. National-
level and other data sources are available to identify wildfires, and 
these allow the EPA to reasonably conclude that other fires are 
prescribed or agricultural fires. Using these sources of wildfire data 
has also revealed that the additional fuel and burning data greatly 
affect and improve the emissions estimates. For prescribed burning, 
however, there is no central collection of national data, and few 
States collect the information that the EPA would need to properly 
label each fire.
    Available evidence indicates that wildfire acres burned have 
increased over time,\68\ which, in turn, has drawn attention to 
prescribed burns as a mitigating measure.\69\ Thus, the EPA expects 
that prescribed burning activity will increase, making it important to 
properly estimate the emission impacts from these sources. 
Additionally, new satellites have become available in the last few 
years that detect many more (and smaller) fire events. As a result, we 
now have information about more fires and have an opportunity to 
improve the current approach for estimating emissions from fire events.
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    \68\ U.S. EPA, Climate change indicators: Wildfires, Figure 5: 
Change in Annual Burned Acreage by State Between 1984-2001 and 2002-
2018. https://www.epa.gov/climate-indicators/climate-change-indicators-wildfires.
    \69\ Hunter, M. E. and Robles, M. D, Tamm review: The effects of 
prescribed fire on wildfire regimes and impacts: A framework for 
comparison. Forest Ecology and Management, 475, 118435. https://www.sciencedirect.com/science/article/pii/S0378112720312044.
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    While some States currently submit data on prescribed burns 
voluntarily, there is currently no national minimum approach to ensure 
collection of information about prescribed burning. While some States 
have permitting programs for prescribed burning to ensure that the 
burns do not cause undue impact on communities, most of those programs 
have not led to collection of data. Many permits may be issued that do 
not result in a burn and its only possible to determine some aspects of 
a burn (such as the acres burned) after it occurs. A minimum set of 
prescribed burning data collected from all States would allow both for 
higher quality emissions data and more equitable characterization of 
the emissions that impact downwind communities.
    The 2015 AERR eliminated the requirement that States report 
emissions from wildfires and prescribed fires, which had been required 
via the 2008 AERR as county totals. At that time, the EPA had believed 
that the satellite-based approach and other available datasets would be 
sufficient to properly characterize emissions from these fires. While 
EPA's expectation has come to pass for wildfire emissions, based on the 
reasons described above, the satellite-based approach is too uncertain 
to properly characterize prescribed burning. Further refinement of the 
wildfire estimation technique will be sought, and EPA encourages 
voluntary submission of wildfire data such as fuel type and consumption 
information that provides refinement of these emissions estimates.
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    \70\ National Association of State Foresters and the Coalition 
of Prescribed Fire Councils, 2020 National Prescribed Fire Use 
Survey Report, December 2020, https://www.stateforesters.org/newsroom/2020-national-prescribed-fire-use-report/.
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    The National Interagency Coordination Center (NICC) estimates that 
between 2009 and 2018, in the United States, on average about 86,300 
prescribed fires burned about 3 million acres annually; however, these 
data are known to be incomplete. The National Prescribed Fire Use 
Survey Report \70\ is a more complete source for estimating prescribed 
acres burned nationally, and the 2020 survey puts the national estimate 
at about 9-10 million acres burned annually. About 75-80 percent of 
these acres burned are in the eastern

[[Page 54183]]

U.S.; the amount of prescribed burning in the western States is small 
in comparison. The 2018 National Prescribed Fire Use Survey Report 
provided an estimate of 11.3 million acres treated with prescribed fire 
in 2017.\71\
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    \71\ National Association of State Foresters and the Coalition 
of Prescribed Fire Councils, 2018 National Prescribed Fire Use 
Survey Report, December 2018, https://www.stateforesters.org/wp-content/uploads/2018/12/2018-Prescribed-Fire-Use-Survey-Report-1.pdf.
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    Other information suggests that even the National Prescribed Fire 
Use Survey report is incomplete. The 2017 NEI estimate that includes 
satellite-based observations and excludes wildfires as best as possible 
put the national prescribed acreage burned for that year at about 14-15 
million. While this may be an over-estimate because many of those fire 
sizes were not documented, the difference in the satellite-based 
estimate as compared documented fires suggests that the National 
Prescribed Fire Use Survey may be incomplete. Another challenge in 
determining whether a fire detection is a wildfire or prescribed fire 
is that both activities sometimes occur at the same time especially in 
areas with high use of prescribed fire such as the southeast.
    The importance of accurate wildfire and prescribed burning data is 
highlighted by the many uses of that data by the EPA and States for air 
quality management: exceptional event determinations, non-attainment 
area inventories for PM and ozone, ozone and PM transport analysis, and 
EPA's air quality modeling to support risk analysis, NAAQS review/risk 
assessments, and regional haze. In addition, the EPA includes the fire 
emissions data in emissions trends to provide environmental information 
for the public and to meet international reporting agreements.
    For the 2017 NEI, prescribed fire emissions data (either activity 
information or emissions) were estimated with voluntary help from 19 
State air quality agencies.\72\ A mandatory prescribed burning 
reporting program would be to the benefit of the many data uses listed 
above. To assess how a mandatory program might be designed, the EPA is 
considering what attributes would need to be part of any mandatory 
prescribed burning reporting program. These attributes are (1) the 
frequency of reporting, (2) the timing of reporting, (3) the size of 
burn events to be reported, (4) the type of burn events to be reported, 
and (5) the minimum data fields needed to address the current 
limitations of the voluntary program. Each of these considerations is 
described here.
---------------------------------------------------------------------------

    \72\ While EPA received the 2017 NEI data from state air quality 
agencies, EPA is aware that many of those states have coordinated 
with their state forestry agencies to provide EPA the data.
---------------------------------------------------------------------------

    The EPA has been estimating daily emissions of prescribed fires for 
CAPs and HAP every year since 2005. These data inform annual fire 
trends and the EPA uses the daily event data as input to annual air 
quality modeling that supports both regulatory and non-regulatory 
agency priorities. As previously described in section IV.G, regulatory 
modeling needs may arise for the EPA and for State SIPs for any year 
and not only triennial inventory years. Thus, the EPA must assume in 
any policy the same potential need for data for every year. 
Additionally, existing data shows that prescribed burning acres can 
vary widely from year to year. As shown in Figure 1a (which is Figure 
7-6 of the 2020 NEI TSD), from between 2006 and 2020, prescribed 
burning acreage ranged from about 7 million acres per year to more than 
15 million acres. Similarly, as shown in Figure 1b (which is Figure 7-5 
of the 2020 NEI TSD), the PM2.5 emissions from prescribed 
burning ranged from about 600,000 tpy to about 1,000,000 tpy. These 
ranges suggest sufficient variability from year to year to support 
annual collection of data.
BILLING CODE 6560-50-P

[[Page 54184]]

[GRAPHIC] [TIFF OMITTED] TP09AU23.033

    In addition to an annual need for prescribed burning data, the 
spatial and temporal differences across years should impact a decision 
on reporting frequency. While grassland prescribed burning tends to 
occur every year in the same locations, forest prescribed burning 
usually occurs in different locations because the undergrowth burned in 
one year is not in need of clearing again the following year. Further, 
for both grasslands and forest prescribed burning, while the general 
time periods are similar from year to year in each State, the specific 
burn timing necessarily varies based on meteorological and air quality 
considerations each year. Consequently, the variability of the data 
suggests that collecting it each year is consistent with the nature of 
the activity which the EPA is seeking to collect data on.
    The EPA is considering both the date that States would report data 
and which inventory year would be the first for any proposed 
requirements. For the reporting date, the EPA is aware that State air 
quality and forestry agencies are in a cycle of managing the current 
fire season and preparing for the next fire season. In recent years, in 
some areas, the fire season has become longer and less predictable, 
which complicates finding an optimal time for any data reporting 
requirement. In general, however, wildfires tend to occur in the summer 
and fall as temperatures are high, vegetation dries out from lack of 
rain, and lightning is more prevalent. Time periods allowed for 
prescribed burning usually occur outside of the wildfire season, 
depending on the area. These facts suggest that, while the summer is a 
busy time because of wildfires, the spring and fall can be a busy time 
for prescribed burning and that the added workload for any prescribed 
burn data reporting might, therefore, benefit from a flexible time 
window during which to report data.
    This workload consideration would also need to be balanced with 
when States could practically complete data collection, QA, and data 
submission, including any coordination necessary between State air 
quality and forestry departments. Not only must State coordination 
internally be considered, but also any coordination needed with the 
representatives of military bases who are responsible for prescribed 
burning on those Federal lands. A final relevant factor for a proposed 
due date is when the EPA would need the data to meet timing objectives 
for the NEI, allowing enough time for review by data partners at State 
air quality and forestry departments.
    To determine the first year for any requirements to report 
prescribed fire data, the EPA is considering the extent to which 
agencies are providing detailed data voluntarily. It is expected that 
any agency not currently providing voluntary input may not have a 
program

[[Page 54185]]

to collect prescribed burning data after the burn has occurred. In the 
2017 and 2020 NEIs, 19 agencies voluntarily participated in providing 
input to the prescribed burning activity data, which is one of the best 
participation rates of any triennial NEI years. To aid in deciding on a 
proposed action and to assess burden, we assumed that 63 State, local, 
or tribal agencies would need to develop some aspect of a prescribed 
burning data collection program. We recognize that there are some areas 
in which prescribed burning does not occur. It is expected that most 
air agencies (States, locals, or tribes) encompassing areas in which 
prescribed burning activity occurs may have a permitting program in 
place from which they could build a data collection program. The EPA 
urges commenters to provide any additional information about how many 
State, local, or tribal agencies may be required to report prescribed 
fire data if the EPA were to finalize the proposed requirements of this 
action.
    EPA is considering the locations from which fires should be 
reported and the size of fires to be included. Regarding the locations 
of fires, the EPA is already able to obtain data needed for some 
Federal lands from national databases,\73\ but military prescribed 
burning is not usually included. Based on analysis of available data 
sources, prescribed burns on private lands within States and on 
military lands appear to be the bulk of the data not currently 
available.
---------------------------------------------------------------------------

    \73\ Hazard Mapping System (National Oceanic and Atmospheric 
Administration); Incident Command System Form 209: Incident Status 
Summary; Forest Service Activity Tracking System (U.S. Forest 
Service); U.S. Fish and Wildland Service fire database.
---------------------------------------------------------------------------

    The EPA has analyzed voluntarily reported data from States for the 
2017 NEI to consider an acreage reporting threshold above which data 
would be required to be reported. The higher the acreage reporting 
threshold, the fewer burns would need to be reported and the lesser the 
burden on States. In that data, almost 90 percent of the acres from 
prescribed burns were from events of 50 acres or more, and 95 percent 
of the acres burned were from burns of 25 acres or more. This finding 
suggests that setting the reporting threshold at either 50 or 25 acres 
should capture the bulk of prescribed burning events occurring on 
State, military and private lands that would be required under this 
proposal. These data generally do not include prescribed burns on 
military lands, and thus no information about those is currently 
available to the EPA for analysis.
    The burden consideration should be balanced with the need to 
characterize satellite-detected burns as being prescribed burns, since 
otherwise they could be characterized as wildfires and assigned higher 
emission rates in creating the NEI. Without other information, the NEI 
approach assigns fires as prescribed burns or wildfires based on the 
satellite data, the State, and the month; a chart of these assumptions 
is available in Figure 2 (based on Figure 7-3 of the 2020 NEI TSD). 
Additional information from States would improve this approach.
[GRAPHIC] [TIFF OMITTED] TP09AU23.034

BILLING CODE 6560-50-C
    The satellite data can also cause uncertainty in the acres burned 
per fire, without ground-based observation data. The pixel size of the 
satellite images determines the default size of these burns, which is 
from 12 to 62 acres per pixel, depending on where in the U.S. the fire 
occurs. Emissions from burns smaller than the assumed acres based on 
pixel size would be overestimated, and emissions from burns larger than 
the assumed size would be underestimated.
    Additionally, the EPA is aware of various types of prescribe burns: 
broadcast burns, understory burning/underburning, and pile burns. These

[[Page 54186]]

burn types are defined by the Bureau of Land Management (BLM) on their 
Prescribed Fire Terminology website.\74\ Broadcast burns are defined as 
``a prescribed fire ignited in areas with little or no forest canopy 
present.'' Understory burning is defined as ``A prescribed fire ignited 
under the forest canopy that focuses on the consumption of surface 
fuels but not the overstory vegetation,'' and pile burns are defined as 
``a prescribed fire used to ignite hand or machine piles of cut 
vegetation resulting from vegetation or fuel management activities.'' 
These burns can have different emission rates and other 
characteristics, so the EPA would ideally have data from all these fire 
types and would know the type of each fire reported. Additionally, 
evidence suggests that in general, broadcast and understory burns 
impact larger acres per event, because collecting material for pile 
burns tends to happen over smaller, more manageable areas. Broadcast 
and understory burning can include cuttings from fuels reduction 
treatments and logging slash.
---------------------------------------------------------------------------

    \74\ Bureau of Land Management, ``Prescribed Burn Terminology,'' 
https://www.blm.gov/or/resources/fire/prescribedburns/burn_terminology.php.
---------------------------------------------------------------------------

    Different information is needed about prescribed burns depending on 
the type of burning. The EPA recognizes that certain data fields needed 
for pile burns are not available in the current reporting formats. 
After consideration, the EPA proposes that for broadcast burns and 
understory burns, the minimum data fields needed are: (1) a unique 
identifier for the State, (2) the date of the burn, (3) State and 
county code or tribal code, (4) the centroid of the latitude/longitude 
coordinates of the burn for that date, (5) SCC (which provides the type 
of burn), and (6) either the acres burned or the total planned acres 
and percent burned. Additional data fields would be available for 
optional reporting, including fuel type, fuel loading per acre, fuel 
moisture (any or all of 1-hr, 10-hr, 100-hr, and 1000-hr values), 
emission reduction technique, and burn perimeter geographic information 
system (GIS) shape data. Emission reduction techniques are smoke 
management practices that are used by fire managers to reduce air 
quality impacts from prescribed fire and include burning fewer acres, 
burning when large woody fuels have a higher fuel moisture content, 
removing fuels before ignition among other techniques.\75\
---------------------------------------------------------------------------

    \75\ National Wildfire Coordinating Group, ``NWCG Smoke 
Management Guide for Prescribed Fire,'' November 2020, PMS 420-3/
NFES 001279, Chapter 4, Section 2, pp. 146-164.
---------------------------------------------------------------------------

    For pile burns for each event, the EPA is considering that the 
minimum data fields are essentially the same as for broadcast or 
understory burns, but rather than acres burned (or total planned acres 
and percent burned) a State would be required to report the number of 
hand piles per acre and the number of machine piles per acres. In 
addition, optional data fields for pile burns would include average 
height and diameter of the piles.
    Given these considerations, this action proposes to require that 
States report data for prescribed burns for certain burns within State 
boundaries, including burns conducted on state-owned/managed, private, 
and military lands. This proposed requirement would exclude reporting 
of burns for which such data are already documented by certain agencies 
or Federal Land Managers via freely provided Federal databases. This 
proposed requirement considers that the EPA already has access to 
prescribed burning data provided by USFS and the Department of the 
Interior and thus avoids duplication of effort by States by excluding 
such data from the proposed requirements (however, States are free to 
report data from Federal lands if they choose to do so). This proposal 
includes new data formats for reporting prescribing burning activity 
data.
    The EPA additionally proposes that agricultural and land clearance 
burns be excluded from the prescribed burns required to be reported. To 
facilitate this exclusion, the EPA proposes to use the definition of 
prescribed burns defined by 40 CFR 51.301 and proposes a definition of 
agricultural burns to mean ``the use of a prescribed fire to burn crop 
residue.''
    EPA is additionally proposing a requirement that State reports on 
prescribed burns would be due within 6 months of the end of the 
inventory year (i.e., the calendar year in which the emissions 
occurred) starting with the 2026 inventory year; thus, if finalized, 
prescribed burning data would be due by July 1, 2027, and then every 
July 1 thereafter. This deadline and others are summarized below in 
section IV.S. The EPA also proposes a requirement for States to report 
data for broadcast and understory burns when such burns impact 50 acres 
or more and to report data for pile burns when biomass is collected 
from 25 acres or more. Further, the EPA proposes to require States to 
report for burns with aspects of both broadcast/understory and pile 
burning that are 25 acres or more and to report each aspect of a burn 
separately. For all burns, the EPA proposes to require the minimum data 
elements previously listed. States would still be able to voluntarily 
report data about fires smaller than those proposed to be required 
above.
    The EPA also is considering the size of the prescribed burns and 
believes that it would be possible to calculate the acreage of a 
prescribed burn in such a way as to avoid additional reporting 
requirements. Therefore, the EPA is proposing a requirement that, in 
determining whether a burn must be reported, States would add acres of 
adjoining parcels of land together when those parcels would be burned 
on the same day (e.g., if two pile burns were conducted on adjoining 
parcels in increments of 15 acres on the same day, those burns would be 
considered as 30 acres and would, under these proposed requirements, be 
reported together because they would exceed the proposed 25-acre 
reporting threshold for pile burns). Finally, irrespective of any 
acreage threshold for mandatory reporting, the EPA intends to retain 
voluntary reporting for fires of any size or type for both wildfire and 
prescribed burning, which includes allowing States to report prescribed 
burns that occurred on Federal lands when they are included in State 
databases.
    One approach to ensure that the EPA has all needed data for 
prescribed burning would be an effort to consolidate existing data 
collection from other Federal agencies with State data collection; 
however, this approach would require additional time, coordination, and 
agreement with other Federal agencies. Proposing an approach that 
requires such coordination would likely delay implementation; 
therefore, in this proposed action, the EPA relies on other Federal 
agencies continuing to provide such data voluntarily. This proposed 
approach would allow the EPA to obtain the information currently 
unavailable (i.e., prescribed burns on state-owned/managed land, 
private land, and military land) without delaying its collection as 
would occur if a coordinated state-Federal approach needed to be 
devised. A similar voluntary approach has been used for point sources, 
in which the Bureau of Ocean Energy Management voluntarily provides 
point source emissions data for offshore oil platforms.
    The EPA is also considering several alternatives in addition to the 
preferred alternative requirements described above. In the preferred 
alternative, the EPA is proposing the 2026 inventory year as the first 
inventory year to allow States more time to develop a prescribed 
burning data collection program. These data would be required by July 
1, 2027,

[[Page 54187]]

and every year thereafter. The EPA requests comment on Alternative M1, 
which would include all aspects of the preferred alternative but would 
start the reporting for the 2025 inventory year and data would be due 
by July 1, 2026, and every year thereafter. The EPA requests comment on 
Alternative M1 because we recognize the importance of creating this new 
data flow about prescribed fires as soon as possible. In support of 
Alternative M1 are several considerations: (1) many States already 
permit prescribed fires and, therefore, the data collection may be more 
easily developed building from a permitting program, (2) the regulatory 
approach for prescribed burning is not on industrial facilities, and 
thus States may have more flexibility in implementation, and (3) States 
may want to push forward quickly with collection of this information to 
better reflect the fire emissions in their State. The EPA urges 
commenters to provide any additional information for the EPA to 
consider that would address the challenges and benefits of an earlier 
start to a prescribed fires requirement.
    The EPA is also soliciting comment on Alternative M2, which would 
provide States more time to implement a prescribed burning reporting 
requirement. Alternative M2 would include all aspects of the proposed 
approach but would delay the reporting to start for the 2027 inventory 
year, with the first collection on July 1, 2028. The primary reason to 
consider this option is that it provides more time for States to 
implement the necessary collection. The disadvantage of this approach 
is that the data are not available sooner when compared to the 
preferred alternative.
    Finally, the EPA is soliciting comment on Alternative M3, which 
would be significantly different from the proposed requirements above. 
Rather than collect data on a per-burn basis, Alternative M3 would 
require States to report the counties, dates, and/or months in which 
prescribed burns occurred. With Alternative M3, the EPA would use the 
satellite detection information along with the additional information 
from States such as comprehensive ground-based wildfire activity to 
improve EPA's assumptions about which fires are prescribed burns. Fires 
identified by satellite would be mapped to the counties, dates, and/or 
months provided by States to better determine whether a fire is a 
prescribed burn or a wildfire and to allow the EPA to use the most 
appropriate emissions factors to estimate emissions. The primary 
advantage of Alternative M3 over the preferred alternative is that it 
lowers the burden on States and could presumably be implemented more 
quickly. If the EPA were to select Alternative M3 (either alone or in 
combination with one of the other alternative above), the EPA could 
implement such a requirement as early as the 2024 inventory year, with 
the same July 1 deadline as described above for the preferred 
alternative. The disadvantage of Alternative M3 is that it does not 
include information about the actual size or type of each burn, which 
would allow for improved emissions estimates. For example, the number 
of acres burned would continue to be estimated based on the pixel size, 
which as previously described can overestimate or underestimate the 
area burned and the emissions.

N. Revisions to Requirements for Agricultural Fires and Optional 
Reporting for Wildfires

    Agricultural burning is an important source of emissions at the 
regional scale and poses a unique challenge on the days in which burns 
occur. The current AERR collects data on emissions of agricultural 
burning from States as a nonpoint source (i.e., annual total emissions 
by county and SCC). However, the day-specific nature of agricultural 
burning can be critical because it can impact local air quality on 
specific days and could contribute to regional haze or other episodic 
pollutant problems in urban and rural environments. As a result of this 
difference between the data collected from States and the timescale on 
which the emissions occur, the EPA has concluded that the current AERR 
requirements are insufficient to fully understand the impact of those 
emissions. In considering improvements to the AERR, the EPA has 
explored how to best gather information on agricultural burning 
emissions.
    The EPA has developed a method to devise day-specific agricultural 
burning emissions. This approach does not rely on state-submitted data 
but can benefit from State input. The EPA is considering that the 
availability of this method to calculate day-specific fires could 
provide useful data without burdening States.
    The idea of day-specific agricultural burning was received as part 
of comments during the public review of the 2013 AERR proposed 
rule.\76\ The EPA's response to those comments stated, ``[t]he the EPA 
disagrees with this comment because the lower emissions associated with 
agricultural fires do not necessitate having the fires as daily 
events.'' \77\ However, since the AERR was finalized in 2015, the EPA 
continued to explore the possible impacts of agricultural burning 
events and has determined that such events could, under the right 
conditions, have a significant enough impact on downwind air quality 
that a day-specific approach could be warranted.
---------------------------------------------------------------------------

    \76\ Comments submitted by Washington Department of Ecology, see 
docket entry EPA-HQ-OAR-2004-0489-0066.
    \77\ See ``AERR Response to Comment document'' see docket entry 
EPA-HQ-OAR-2004-0489-0077.
---------------------------------------------------------------------------

    Under the current AERR and for the 2017 NEI, six States and four 
tribes submitted nonpoint, annual total emissions of agricultural 
fires. To use these emissions for air quality modeling, the EPA uses 
its own day-specific estimates to apportion the state-submitted 
nonpoint data to days. This process can lead to errors when compared 
with using day-specific ``event'' data, as is done for wildfires and 
prescribed burning. The remaining State, local, and tribal agencies 
either notified the EPA that they excepted EPA agricultural fire 
emissions, or they were silent on this topic. This information suggests 
that most States support EPA's agricultural fires method and would not 
be impacted by any changes made to reporting requirements.
    Based on these considerations, the EPA proposes to add a new 
subparagraph Sec.  51.15(h) in the proposed regulatory text that would 
specify that when States report agricultural burning emissions, the 
data would need to be reported in the same event-based data format as 
is used for prescribed burning. Furthermore, this action allows for the 
EPA to continue to provide the agricultural fires as day-specific data 
for States to review, comment, or revise event-based submissions. This 
proposed revision would take effect starting with the 2023 inventory 
year.
    The current AERR allows for voluntary reporting by States of 
wildfire emissions. Rather than reporting emissions, most States have 
reviewed and commented on EPA's activity data compiled from national 
databases in conjunction with satellite data. To formalize that 
approach, the EPA proposes that States could voluntarily review and 
comment on EPA-provided wildfire activity and emissions data. In 
addition, the EPA proposes that a State may report wildfire timing and 
activity data using the same event-based data format as is used for 
prescribed burning.

O. Revisions for Onroad and Nonroad Emissions Reporting for California

    The EPA approves onroad mobile models for California for 
transportation

[[Page 54188]]

conformity purposes and for use in SIPs. For the current AERR, 
California is already required to report emissions from onroad mobile 
sources rather than report MOVES inputs. While there is no EPA-approved 
nonroad model, California has its own state-specific model. The current 
AERR requirements, however, have limitations on two points that the EPA 
has reconsidered in developing this proposed action.
    First, the current AERR does not specify what version of the 
California onroad mobile model should be used when reporting to EPA, 
nor what pollutants should be reported for onroad and nonroad mobile 
sources. In reevaluating the existing requirements, the EPA is 
proposing new language that would specify using an approved version of 
the California onroad mobile model. This would ensure data quality and 
that the latest methods are used, which would be consistent with EPA's 
use of the latest version of MOVES for other States. In addition, the 
EPA proposes that this subpart requires the same CAPs from California 
as States.
    Second, the existing requirements cause a limitation in EPA's 
understanding of how California has applied its model to estimate 
emissions. Since there is no requirement to provide documentation, 
there is no way for the EPA to provide transparency for NEI users about 
the emissions data or QA measures that have been taken.
    Based on these considerations, the EPA proposes to add a new Sec.  
51.15(e)(3) in the proposed regulatory text to specify that the EPA 
would retain the existing approach of requiring California to report 
CAP emissions from onroad and nonroad sources. The EPA additionally 
proposes to include three new requirements to this subpart to address 
the issues identified during EPA's review.
    First, to resolve the question of the latest version of the onroad 
mobile model, the EPA proposes to add a new Sec.  51.5(m) in the 
proposed regulatory text that would require California to use the 
latest model version approved by the EPA as of January 1 of the 
emissions inventory year and may optionally use a newer approved model. 
For example, the onroad model approved as of January 1, 2023, should be 
used to estimate and report emissions to meet the proposed requirements 
in the new subparagraph Sec.  51.15(e)(3) of the proposed regulatory 
text for the 2023 reporting year, or the State could optionally choose 
to use a model approved by the EPA after that date.
    Second, to resolve the question of which pollutants should be 
reported, the EPA proposes to add a new subparagraph Sec.  
51.15(e)(3)(i) in the proposed regulatory text that would require 
California to report emissions values for the same pollutants estimated 
by the EPA model for criteria pollutants and precursors. Additionally, 
this action proposes to add a new subparagraph Sec.  51.15(e)(3)(iii) 
that would specify that California may voluntarily submit emissions of 
HAP, greenhouse gases, or other pollutants, consistent with those 
pollutants that are estimated by the MOVES model. If California does 
not report these data, the EPA intends to use CAP/HAP ratios consistent 
with the MOVES model and if California does report such emissions, the 
EPA will evaluate the data and documentation to decide which approach 
would be to the best advantage for the purposes of the NEI.
    Third, to resolve the lack of documentation about California's 
onroad and nonroad mobile emissions, the EPA proposes to add a new 
subparagraph Sec.  51.15(e)(3)(ii) in the proposed regulatory text that 
would require California to submit documentation that describes the 
model inputs, use of the model and any options selected, post-
processing steps, and the QA performed to estimate the emissions for 
each county and SCC. This proposed requirement would allow commensurate 
documentation, quality review, and transparency for California's onroad 
and nonroad emissions as exists for mobile sources in the NEI for other 
States. The EPA intends to evaluate the documentation provided by 
California, particularly for HAP, and determine the best approach for 
ensuring complete HAP data from mobile sources that uses sufficiently 
robust and transparent approaches.

P. Clarifications for Reporting Emission Model Inputs for Onroad and 
Nonroad Sources

    The current version of the AERR requires States, except for 
California, to report MOVES model inputs for onroad and nonroad sources 
or to accept EPA-provided emissions data. The EPA has reviewed the 
current process and is aware that States may have access to better data 
than the EPA can obtain on its own, for example, to vehicle 
registration data and inspection and maintained program data maintained 
by States that are not available in any national databases (except as 
collected under this subpart). The EPA recognizes that the current AERR 
is not specific about which parts of the MOVES model inputs are most 
critical or whether there are some parts of those inputs that the EPA 
would not use. Additional clarification about which MOVES inputs are 
the most important could encourage States to submit at least that 
minimum amount of data and could also help to avoid misunderstandings 
regarding which data elements the EPA does not intend to use.
    In addition, the current AERR does not specify a mechanism by which 
States may express their review and acceptance of EPA-provided MOVES 
inputs and emissions. Like nonpoint sources as described above, such a 
mechanism would be useful to allow the EPA to develop a formal record 
of States' choices about submitting model inputs or accepting EPA 
inputs and emissions.
    Furthermore, some States do not notify the EPA of their acceptance 
of MOVES inputs or emissions. While the EPA might simply assume that no 
notification means that States do accept it, such an approach does not 
create a clear record for the EPA if disputes in emissions data arise 
later. Resolving this limitation of the current process would avoid 
possible conflicts in the future.
    While many States submit MOVES inputs, some States still do not. 
Section 5.5 (Table 5-4) of the 2020 NEI TSD describes that 28 States, 
including the District of Columbia, and 5 local agencies provided MOVES 
inputs, out of 82 total States and local agencies reporting. 
Furthermore, different agencies provided different degrees of input, 
suggesting that an approach to clarify the most important data formally 
with this action could be useful to agencies seeking to prioritize 
their efforts. While there are many separate inputs listed in the 2020 
NEI TSD, just a handful of these are most important to receive from 
States.
    To ensure more data provision by States and avoid confusion, the 
EPA proposes to list the minimal MOVES input requirements. 
Specifically, the new Sec.  51.15(e)(1) included in the proposed 
regulatory text would require that the minimum requirements for States 
to provide are: (1) a county database checklist, (2) vehicle miles 
travelled by county and road type, and (3) vehicle population by 
county, vehicle type, fuel type, and age.
    Further, this action proposes to clarify with the new Sec.  
51.15(e)(2) in the proposed regulatory text that if a State has 
relevant data for the inventory year, States may optionally provide 
inputs to the latest EPA-developed mobile emissions model for the 
following data: (1) hourly average speed distribution by vehicle type, 
ideally different for weekday and weekend (distance traveled in miles 
divided by the time in hours), (2) vehicle age distribution, (3) 
inspection and maintenance program

[[Page 54189]]

information, and (4) documentation that describes how model inputs were 
created and the QA steps performed. The intent of listing out these 
optional MOVES inputs is to explicitly exclude those MOVES inputs that 
the EPA does not intend to use, which are fuel data and meteorological 
data. Any fuel data that States would like the EPA to consider should 
be incorporated into the default MOVES database. If available, States 
may optionally send fuel data to the EPA at [email protected].
    As noted above, some States do not notify the EPA of their 
acceptance of EPA-provided MOVES inputs and emissions. To address this 
issue, the EPA is proposing a more formal approach in future inventory 
years. If a State were to not respond using the standard approach 
provided, the EPA could follow up with the State to notify them of the 
compliance concerns and allow the State the opportunity to comply with 
the AERR.
    To address this issue, the EPA proposes to add a new subparagraph 
Sec.  51.15(e)(4) in the proposed regulatory text to clarify that 
States other than California may, in lieu of submitting any data, 
review and accept existing the EPA model inputs and emission estimates. 
The EPA further proposes in the paragraph that States would be required 
to use an electronic data collection approach provided by the EPA to 
review, comment on, and accept EPA model inputs and emission estimates. 
The approach that the EPA would implement to support that proposed 
requirement would be in EIS like the Nonpoint Survey described in 
section IV.J of this preamble or an approach to upload data files and 
enter data on a shared folder such as Sharepoint. This goal with these 
proposed provisions is to achieve the consistency needed for the Agency 
to avoid the potential problems created under the current less specific 
approach.

Q. Definition of Actual Emissions

    The term ``actual emissions'' is used in CAA sections 112, 172, and 
182 among others, but no definition is provided of that term by the 
Act. In CAA section 112(a), the term is used to define the terms 
``modification,'' ``offsets,'' and ``early reduction.'' In CAA section 
172(c)(3) and section 182(a)(1), the term is used to describe the 
emissions that must be reported by States as part of SIPs. Because this 
subpart implements aspects of the Act for emissions reporting to EPA, a 
definition of this term that is appropriate for reporting of emissions 
would be useful to ensure clarity about which emissions are required to 
be reported. The EPA recognizes that the phrase ``actual emissions'' is 
used in other contexts within 40 CFR part 51 that are distinct from the 
emissions data reporting context. The proposed definition would only 
apply to the provisions of the AERR; therefore, it would affect both 
annual emissions data reporting as well as emissions included in SIP 
inventories.
    The current AERR regulations in Subpart A of Part 51 have not 
previously provided a definition of ``actual emissions'' for use in 
implementing this subpart. A lack of a definition has caused confusion 
because emissions generating activities can be divided into categories, 
including emissions occurring during (1) steady State operating 
conditions, (2) periods of process startup or shutdown, and (3) periods 
of process malfunction. This confusion has prompted the need for the 
EPA to clarify.
    To attempt to clarify what should be reported for SIP purposes, the 
EPA has previously included a definition of ``actual emissions'' 
through the guidance document ``Emissions Inventory Guidance for 
Implementation of Ozone and Particulate Matter National Ambient Air 
Quality Standards (NAAQS) and Regional Haze Regulations.'' \78\ The 
guidance definition States, ``actual emissions means the emissions of a 
pollutant from an affected source determined by taking into account 
actual emission rates associated with normal source operation and 
actual or representative production rates (i.e., capacity utilization 
and hours of operation) (40 CFR 51.491). This is in contrast with 
potential emissions or allowable emissions. These actual emissions 
should include emissions of a pollutant that occur during periods of 
startup, shutdown, and malfunction.''
---------------------------------------------------------------------------

    \78\ Emissions Inventory Guidance for Implementation of Ozone 
and Particulate Matter National Ambient Air Quality Standards 
(NAAQS) and Regional Haze Regulations, U.S. EPA, EPA-454/B-17-002, 
May 2017.
---------------------------------------------------------------------------

    The EPA is also considering the connection between the term actual 
emissions and duration of the emissions for the NEI (annual) versus for 
SIPs that can include other durations (e.g., ozone-season-weekday for 
the ozone NAAQS or average season day for the 24-hour PM2.5 
NAAQS). To support all EPA functions that use data collected by the 
AERR, the term actual emissions in the context of the AERR must reflect 
the types of activities relevant to include in an emission value rather 
than whether that emissions value is annual or some other temporal 
resolution like average day. Thus, an ideal definition for the AERR 
would allow for the annual NEI reporting to refer to ``annual actual 
emissions'' while an ozone SIP requirement ozone-summer-weekday 
emissions could also be ``actual emissions'' associated with summer 
weekdays.
    Based on these considerations, the EPA proposes to add a definition 
of ``actual emissions'' within Sec.  51.50 of this subpart. The 
proposes definition states, ``Actual emissions'' means, for the 
purposes of this subpart, the emissions of a pollutant from a source 
that is required to be reported under this rule, determined by 
accounting for actual emission rates associated with normal source 
operation and actual or representative production rates (i.e., capacity 
utilization and hours of operation). Actual emissions include emissions 
of a pollutant that occur during periods of startup, shutdown, and may 
include malfunctions. Since malfunctions are, by nature, unpredictable 
and given the myriad different types of malfunctions that can occur, 
malfunction emissions are difficult to estimate. However, to the extent 
that malfunctions become a regular and predictable event, then such 
emissions should be quantified with regular and predictable emissions 
and included in actual emissions.''
    To the extent that malfunction emissions can be included in the 
emissions reported under the AERR, the EPA is additionally considering 
that emissions from malfunctions may need to have special treatment for 
use in both the NEI and SIP contexts. For example, when the emissions 
are used for air quality modeling for model performance evaluation, it 
would be critical to have the time span during which malfunction-
related emissions occurred. If malfunction emissions were included as a 
single value summed with other emissions, then the emissions would not 
exhibit the hourly or daily peaks in emissions associated with the 
malfunction. This would not only miss those peak impacts during the 
times of the malfunction, but also could increase emissions across the 
entire year to a level not useful for model performance evaluation. 
Another example is that for projected inventories required for the 
nonattainment area for the PM2.5 SIP or for ozone and 
PM2.5 modeled attainment demonstrations, including 
malfunctions from the base year in future year modeling may not result 
in the best policy outcomes. This is because malfunctions, if they 
occurred in the future year, would undoubtedly be different in both 
timing and magnitude. Since malfunctions by definition are not

[[Page 54190]]

predictable, including them in future year modeling could be 
problematic.
    The EPA is soliciting comment on a possible additional requirement 
that may be included in any final action on this proposal. This 
additional ``Malfunction Option'' requirement would be for States and 
owners/operators to report their malfunction emissions as a separate 
value from the other emissions. This would allow for consistency across 
NEI, SIPs, and all States to ensure that both malfunction emissions are 
included (based on the proposed definition), but also the malfunction 
emissions do not adversely impact the use of the emissions data for 
some purposes such as modeling and projected inventories. If the EPA 
were to require the Malfunction Option in the final rule, States and 
owners/operators would need to report the approximate date of 
occurrence, the approximate number of days of the occurrence (if more 
than one day), and the estimated emissions associated with each 
malfunction. These additional fields would be reported as associated 
with the affected units and processes (when applicable) and release 
points. The EPA proposes that reporters would assign each emissions 
value with an emissions operating type code that denotes the emissions 
as being associated with a malfunction. In addition, the EPA intends to 
adjust the available codes in the EIS (and CAERS) by retiring the 
existing codes and creating codes for routine (steady-state and 
startup/shutdown), malfunction, and startup/shutdown. Under this 
proposed requirement, the routine value would always be required (and 
as described above, would be expected to include startup/shutdown). The 
malfunction value would be required in the event of a malfunction. The 
startup/shutdown value would be an optional value that a State or 
owner/operator could provide to give additional information about the 
startup/shutdown portion of the routine emissions.
    EPA is additionally considering an alternative implementation of 
the Malfunction Option. In this alternative implementation, rather than 
requiring approximate date, approximate duration, and associated 
emissions, owners/operators would only need to report the annual total 
emissions and the emissions operating type code for all malfunctions 
that occurred each year.

R. Provisions for State Implementation Plans

    To promote a consistent approach to emissions inventory data 
collection from States, portions of 40 CFR part 51 that address SIP 
requirements reference the current AERR when addressing SIP inventory 
requirements. Within Part 51, Subparts G, P, X, Z, AA, and CC all 
reference the AERR. The EPA has reviewed these references to the AERR 
to ensure that the changes proposed to the AERR do not require changes 
to those other subparts. The EPA determined that no such changes to 
these other subparts were necessary. However, the EPA did identify 
certain aspects of the current AERR and proposed AERR revisions that 
could cause confusion for SIP inventory requirements. As a result, the 
EPA is proposing additional revisions within the AERR to prevent such 
confusion, and these changes relate to three considerations: (1) the 
definition of point sources, (2) the level of detail required for 
emission inventories, and (3) the timing of the triennial NEI. Each of 
these considerations is handled separately in the paragraphs below.
1. Point Source Thresholds
    Subpart G refers to the AERR point source definition directly or 
indirectly at Sec.  51.122(g); Subpart X at Sec.  51.915; Subpart Z at 
Sec.  51.1008(a)(1), (a)(2) and (b)(1); Subpart AA at Sec.  51.1115(d) 
and (e), and Subpart CC at Sec.  51.1315(d) and (e). Subpart G directs 
States to submit a statewide NOx emissions inventory and, in doing so, 
to use the AERR point source definition. The ozone implementation rules 
(Subparts X, AA, and CC) require States to report point sources for the 
base year inventory for the nonattainment area using the AERR point 
source definition. Finally, the PM implementation rule of Subpart Z 
directs States to use the AERR point source definition to determine 
point sources, which applies for both the base year inventory and for 
the attainment projected inventory for the nonattainment area.
    In referencing the AERR, the SIP inventory requirements do not 
mention specific pollutants for which the AERR point source definition 
(which uses reporting thresholds for all CAPs) should be used. For 
example, the ozone implementation rules' inventory requirements rely on 
CAA section 172(c)(3), which requires emissions of ``the relevant 
pollutant or pollutants'' when preparing nonattainment SIP inventories 
for ozone. In the case of ozone, these relevant pollutants are 
NOX and VOC, but the references from the ozone SIP 
requirement rules to the AERR are not specific to these pollutants. 
Thus, under the current approach, one could incorrectly assume that all 
AERR point sources defined with all CAP PTE reporting thresholds would 
need to be treated as point sources for an ozone SIP, irrespective of 
the level of NOX and VOC at those sources. This proposal 
clarifies that only those sources with NOX or VOC emissions 
exceeding the AERR point source PTE reporting thresholds would be 
required to be reported as point sources in an ozone SIP. Similarly, 
this proposal would include similar clarifications for PM2.5 
and its precursors when preparing nonattainment SIP inventories for 
PM2.5. In addition, the EPA intends for the addition to the 
point source definition included in this proposal based on HAP should 
not impact the point source definition for SIPs.
    To ensure no change to the other subparts that refer to the AERR's 
point source requirements, the EPA proposes to revise Sec.  51.10 of 
this subpart by adding paragraph (b) to list Part 51 Subparts G, X, Z, 
AA, and CC and specify the parts of the point source definition that 
are applicable to each. Specifically, for Subpart G, the EPA proposes 
that only the NOX reporting threshold of the proposed Table 
1A to Appendix A of this subpart would be relevant. For ozone 
implementation under Subparts X, AA, and CC, the EPA proposes that the 
NOX and VOC reporting thresholds of the proposed Table 1A to 
Appendix A of this subpart would be relevant. For PM implementation 
under Subpart Z, the EPA proposes that the NOX, VOC, 
SO2, NH3, PM2.5, and PM10 
reporting thresholds of the proposed Table 1A to Appendix A of this 
subpart would be relevant.
2. Detail Required by Emission Inventory Provisions of SIP 
Implementation Rules
    In addition to the point source definition referenced throughout 
Part 51, the SIP requirements within Part 51 refer to the AERR by 
requiring that the detail of the emissions inventory under those 
subparts ``shall be consistent with the data elements required by 40 
CFR part 51, subpart A'' (see 40 CFR 51.122(g), Sec.  51.915, Sec.  
51.1008 (a)(1)(vi), Sec.  51.1115(e), and Sec.  51.1315(e)). Several 
revisions are being proposed by this action that would impact the 
``detail of the emissions inventory,'' so additional information has 
been included in this proposed action to clarify which changes do not 
apply to the SIP inventory requirements.
    The proposed revisions to this subpart for State requirements 
regarding the ``detail of the emissions inventory'' have been described 
above and are summarized here to provide clarity about which changes 
would need to be considered when interpreting the Part

[[Page 54191]]

51 references to the AERR. Table 4 below lists the proposed changes to 
relevant requirements of action in the left column and how the EPA 
proposes that they would or would not impact the ``detail of the 
emission inventory'' requirement included in the SIP inventory 
requirements.

   Table 4--Impacts of Proposed State Reporting Requirements on 40 CFR
                      Subparts G, X, Z, AA, and CC
------------------------------------------------------------------------
                                                   Impact of proposed
                     Proposed new or revised     requirement on 40 CFR
                         State  reporting      subparts G, X, Z, AA, and
                     requirement for the AERR         CC? (Yes/No)
------------------------------------------------------------------------
1.................  Requirement to report      No: Does not change
                     intermittent electricity   emissions required to be
                     generation fuel use        reported under these
                     (section IV.D of this      subparts. Emissions (but
                     preamble).                 not daily activity data)
                                                from intermittent
                                                electricity generation
                                                sources would continue
                                                to be required to be
                                                included in SIP
                                                inventories. The
                                                proposed AERR revisions
                                                improve States' ability
                                                to gather the data they
                                                need to estimate and
                                                consider these emissions
                                                in SIPs.
2.................  Requirements to use        Yes: Point source
                     source test data when      emissions would need to
                     available, indicate why    be estimated as proposed
                     it is not used, and        in new Sec.   51.5(a)
                     otherwise use best         through (d) of the
                     available emissions        proposed regulatory
                     estimation method          text.
                     (sections IV.I.6 and
                     IV.I.7 of this preamble).
3.................  Additional required point  Yes: Point source
                     source data fields         inventories developed
                     (sections IV.E, IV.I.3,    and submitted under
                     IV.I.4, IV.I.5, IV.I.8,    these subparts would
                     IV.I.10, IV.I.11,          need to include
                     IV.I.12, and IV.I.16 of    additional data fields.
                     this preamble).            See new Sec.
                                                51.15(j)(1) and Sec.
                                                51.40(b) of the proposed
                                                regulatory text.
4.................  More specific airport and  No: Airport and rail yard
                     rail yard requirements     emissions are still
                     and implementation         required as point
                     options (sections IV.I.1   sources if those
                     and IV.I.2 of this         facilities exceed the
                     preamble).                 point source reporting
                                                thresholds in Table 1A
                                                to Appendix A of this
                                                subpart. See new Sec.
                                                51.15(j)(1) of the
                                                proposed regulatory
                                                text.
5.................  Requirement to complete    No: Only relevant for NEI
                     an online nonpoint         process and not for
                     survey (section IV.J of    SIPs. See New Sec.
                     this preamble).            51.15 and Sec.
                                                51.15(j)(2) of the
                                                proposed regulatory
                                                text.
6.................  Requirement to report      No: Nonpoint emissions
                     nonpoint activity data     are still required. See
                     and optionally report      new Sec.   51.15 and
                     emissions data for some    Sec.   51.15(j)(2) of
                     emissions sectors,         the proposed regulatory
                     including an option to     text.
                     review and accept EPA-
                     provided data to comply
                     (section IV.J of this
                     preamble).
7.................  Requirement for            No: Nonpoint emissions
                     documentation when         are still required and
                     nonpoint emissions are     no additional
                     reported (section IV.J     documentation
                     of this preamble).         requirement. See new
                                                Sec.   51.15 and Sec.
                                                51.15(j)(2) of the
                                                proposed regulatory
                                                text.
8.................  Requirement for            No: Onroad and nonroad
                     documentation when         emissions are still
                     onroad and nonroad         required and no
                     emissions are reported     additional documentation
                     by California or by        requirement. See new
                     other States when they     Sec.   51.15 and Sec.
                     optionally provide         51.15(j)(3) of the
                     emissions in addition to   proposed regulatory
                     MOVES inputs (section      text.
                     IV.O of this preamble).
9.................  Specific approach for      Yes (for States
                     reporting nonpoint         overlapping tribes that
                     activity data and          have emissions inventory
                     emissions when Indian      reporting obligations):
                     country boundaries         Clarifies how States and
                     overlap with county        tribes should report
                     boundaries (section IV.L   nonpoint, onroad, and
                     of this preamble).         nonroad emissions when
                                                both the State and the
                                                tribe have
                                                implementation planning
                                                authority within a
                                                nonattainment area. See
                                                new Sec.   51.15 and
                                                Sec.   51.15(j)
                                                paragraphs (2)(iv) and
                                                (3)(ii) of the proposed
                                                regulatory text.
10................  Requirement to report      No: Prescribed fire
                     prescribed burning         emissions are still
                     activity data (section     required. See new Sec.
                     IV.M of this preamble).    51.15 and Sec.
                                                51.15(j)(2)(ii) of the
                                                proposed regulatory
                                                text.
11................  Change to make             No: Agricultural burning
                     agricultural burning       emissions are still
                     optional and submitted     required as a nonpoint
                     as an event source         source. See new Sec.
                     (section IV.N of this      51.15 and Sec.
                     preamble).                 51.15(j)(2)(ii) of the
                                                proposed regulatory
                                                text.
------------------------------------------------------------------------

    As shown in the table above, only three of the proposed changes for 
State annual or triennial reporting under this action impact the 
requirements of Part 51 Subparts G, X, Z, AA, and CC. The three that do 
impact the requirements help with resolving ongoing nonattainment 
emissions data challenges, so it is appropriate for these subparts to 
continue to refer to the AERR as revised.
    For the proposed requirement 1 in Table 4, more completely 
described in section IV.D of this preamble, the proposed change to the 
AERR has a positive impact on emissions data that would be available to 
the State after implementing the provisions of this action. This 
proposed action facilitates activity data collection from small 
generating units as an annual requirement, which would allow States 
with small generating units operating to offset or meet peak 
electricity demand to have the data that they need to better reflect 
emissions from such sources in their planning inventories for SIPs.
    The proposed set of requirements listed as item 2 in Table 5 
specifies data quality requirements for calculating and reporting 
emissions for point sources. These are described more completely in 
sections IV.I.6 and IV.I.7 of this preamble. If these proposed 
requirements were finalized, point sources reporting CAP emissions to 
States for both annual emissions reporting to the EPA and SIP purposes 
would need to meet new data quality requirements.
    The proposed requirement 3 in Table 4 is a collection of specific 
new data fields that are more completely described in section IV.I of 
this preamble and the proposed Table 2A to Appendix A of this subpart. 
Any new data elements finalized from this proposed action would be 
collected by States to meet requirements of the AERR and, therefore, 
would be available for States to submit as part of their planning 
inventories for SIPs. Thus, while the SIP inventory requirements are 
indirectly modified by this proposed action, this

[[Page 54192]]

action does not impose additional burden for nonattainment area 
inventories because this subpart uses the same requirements for both 
annual reporting of point sources and for States' planning inventories 
for SIPs.
    Finally, the proposed requirement 9 of proposed Table 4 is fully 
described in section IV.L of this preamble addresses an existing 
challenge for both the NEI and SIP planning inventories. As previously 
described, a clear approach for States and tribes to share reporting of 
county total emissions data has not been available. When both a State 
and an Indian Tribe share implementation planning authority for a 
nonattainment area, this action proposes a new requirement for how 
States and tribes (or the EPA on their behalf) should develop and 
report nonpoint, onroad, and nonroad emissions. As proposed in new 
paragraph Sec.  51.15(j), subparagraphs (2)(iv) and (3)(ii) of the 
proposed regulatory text, the approach would apply the same technique 
described for nonpoint activity and emissions for triennial reporting 
to the emissions reporting for the nonattainment area needed for SIPs. 
To be clear, this situation would arise if the nonattainment area 
included some lands that fell within the geographic scope of the 
State's implementation planning authority as well as some lands within 
the geographic scope of the tribe's implementation planning authority 
in accordance with TAS for that tribe.
    In evaluating the connection between the elements required to be 
reported under the AERR and the elements required to be provided in SIP 
submissions pursuant to other Part 51 subparts that generally reference 
the AERR, the EPA noticed several differences. The current AERR 
includes some requirements that were intended to apply only to the 
triennial NEI emissions data collection and not to impact requirements 
for SIPs. The primary discrepancy is that as per CAA Section 172(c)(3), 
SIPs ``shall include a comprehensive . . . inventory of actual 
emissions from all sources of the relevant pollutant or pollutants.'' 
The ``comprehensive'' and ``all sources'' part of this requirement are 
not technically satisfied for certain provisions of the AERR. For 
example, the AERR allows for reporting model inputs (rather than 
``emissions'') for mobile sources. Similarly, the AERR makes optional 
certain important emissions sources such as windblown dust, biogenic 
emissions from soils and vegetation, prescribed fires, and wildfires, 
but these sources must generally be included in inventories pursuant to 
172(c)(3). The EPA provides guidance documents and training for SIP 
inventory preparation that help ensure that these differences do not 
result in inadequate SIP inventories. This action proposes to provide 
additional clarity on these issues regarding what States need to 
report.
    Part of this additional clarity has previously been described in 
section IV.R.1 of this preamble regarding which pollutants should be 
included in SIP planning inventories associated with the Part 51 
subparts that reference the AERR. In addition, this proposed action 
includes a new paragraph Sec.  51.15(j) in the proposed regulatory text 
that lists out inventory requirements for SIPs required under Part 51 
Subparts G, X, Z, AA, and CC that are different from requirements for 
annual or triennial reporting for the NEI. First, this proposed action, 
when referring to SIP planning inventories, would define point sources 
only by the relevant CAP point source reporting thresholds under a new 
paragraph Sec.  51.10(b) in the proposed regulatory text and not by the 
other criteria such as the new criteria for HAP for major and non-major 
sources. This proposed revision would retain the existing definition of 
point sources in this subpart for references from other Part 51 
subparts to the AERR. Second, this proposed action would clarify that 
for SIP planning inventories, airports and railyards would need to be 
reported as point sources only when they meet the point source 
reporting threshold and otherwise could be included as a nonpoint 
(county-total) source. This contrasts with the triennial requirement 
for which the EPA provides data for review and comment by States for 
all airports and railyard data, including ones much smaller than the 
point source reporting thresholds. Third, this proposed action would 
further clarify in new paragraph Sec.  51.15(j)(2)(iii) that SIP 
planning inventories should include emissions from all sources, 
irrespective of any other approaches required or made optionally 
available by the AERR for the triennial submission of nonpoint, onroad, 
and nonroad sources.
3. Emission Inventory Years
    The third and final type of reference to the AERR from other 
subparts within Part 51 is about the year of the triennial NEI. Such 
references appear in Subpart P at Sec.  51.308(f)(2)(iii) and Sec.  
51.308(g)(4); Subpart X at Sec.  51.910(d); Subpart AA at Sec.  
51.1110(b), and Subpart CC at Sec.  51.1310(b).
    Subpart P provides requirements for State implementation of the 
regional haze program, and Sec.  51.308(f)(2) provides the requirements 
for the long-term strategy to be included in periodic revisions of 
regional haze SIPs. For emissions inventories, paragraph (f)(20)(ii) 
states that ``[t]he emissions information must include, but need not be 
limited to, information on emissions in a year at least as recent as 
the most recent year for which the State has submitted emission 
inventory information to the Administrator in compliance with the 
triennial reporting requirements of Subpart A of this part.'' 
Additionally, paragraph (g)(4) of the same section provides 
requirements for periodic reports describing progress towards the 
reasonable progress goals; and this paragraph has a similar reference 
to the year of triennial submissions to indicate the period over which 
the State must perform an analysis tracking the change in emissions. No 
provision of this proposed action would impact the inventory year 
required for regional haze SIPs, because this action proposes to retain 
triennial inventory requirements. Thus, under this action, the subpart 
P requirement that references triennial reporting is still relevant 
since emissions inventories would continue under this proposed action 
to be collected on triennial inventory years.
    Within Part 51 Subpart X, Sec.  51.910(d) addresses what year 
should be used for the baseline emissions inventory for Reasonable 
Further Progress (RFP) plans. This paragraph requires that the 
appropriate year is at least as recent as the most recent year for 
which a complete inventory is required to be submitted to the EPA under 
the provisions of the AERR. The phrase ``complete inventory'' means the 
triennial inventory, which are the only inventories for which all 
source categories could be reported by a State under the AERR. No 
provision of this proposed action would impact the inventory year 
required for SIPs under Subpart X, because this action proposes to 
retain triennial inventory requirements.
    Part 51 Subpart AA includes the same statement to specify the 
baseline emission inventory year needed to meet requirements for RFP, 
which appears at Sec.  51.1110(b). In addition, Sec.  51.1115(a) refers 
to the year used for the baseline emission inventory for RFP to explain 
which years can be used for the base year inventory for the 
nonattainment area. Likewise, Part 51 Subpart CC includes the same 
reference to the triennial inventory year at Sec.  51.1310(b). In all 
cases, no provision of this proposed action would impact the inventory 
year required for SIPs under Subparts X, AA, or CC because this

[[Page 54193]]

action proposes to retain triennial inventory requirements.

S. Summary of Expected Timing for Proposed Revisions

    Unless otherwise noted, the proposed revisions in this action would 
apply for the first inventory reporting year after promulgation of the 
final rule. At the time of this proposal, the EPA expects that the 
final rule will be in place for the 2023 triennial reporting year, 
though some provisions would not take effect until later years. These 
proposed deadlines depend on an assumed final rule promulgation date 
prior to December 2024. If a final version of this subpart were delayed 
beyond December 2024, the EPA may delay the phase-in of earlier 
deadlines. Table 5 below summarizes the intent of this proposed action 
with respect to deadlines.

   Table 5--Proposed First Possible Date for Deadlines Associated With
                Proposed Revisions to 40 CFR 51 Subpart A
------------------------------------------------------------------------
     First possible date                      Requirement
------------------------------------------------------------------------
                     Dates for States--point sources
------------------------------------------------------------------------
11/1/2025....................  Proposed first deadline to notify the EPA
                                if intend to use CAERS (for 2026
                                inventory year).
9/30/2024....................  Proposed first deadline for States/locals
                                to submit landing and takeoff data for
                                the 2023 inventory year (could be later
                                than this, since States have minimum of
                                60 dates to review).
1/15/2025....................  Proposed deadline for air agencies 2023
                                NEI point source reporting (for CAP and
                                voluntary HAP including airports and
                                rail yards).
1/15/2026....................  Proposed deadline for air agencies 2024
                                NEI point source reporting (for CAP and
                                voluntary HAP).
3/31/2026....................  Proposed first deadline for States to
                                submit their HAP reporting application
                                (for the 2026 inventory year).
1/15/2027....................  Proposed deadline for 2025 NEI point
                                source reporting (for CAP and voluntary
                                HAP).
1/15/2028....................  Proposed deadline for 2026 NEI point
                                source reporting, for CAP and mandatory
                                HAP when the State has an approved HAP
                                reporting application. Includes the
                                first year for mandatory reporting for
                                intermittent EGUs and required new data
                                fields including release point
                                coordinates, title V permit ID,
                                regulatory codes, and changes to
                                portable sources reporting.
9/30/2028....................  Proposed first deadline for earlier State
                                point source reporting (for 2027
                                inventory year). This is also the first
                                deadline for which the same point
                                sources must be reported each year (no
                                higher reporting thresholds for non-
                                triennial inventories).
5/31/2031....................  Proposed first deadline for even earlier
                                State point source reporting (for 2030
                                inventory year and later).
------------------------------------------------------------------------
              Dates for States--other sources besides point
------------------------------------------------------------------------
1/15/2025....................  Proposed deadline for 2023 NEI for rail
                                yards, mobile source inputs, California
                                mobile source emissions and
                                documentation, and nonpoint source
                                emissions and documentation for sources
                                without EPA tools.
3/31/2025....................  Proposed deadline for 2023 NEI nonpoint
                                survey.
7/1/2027.....................  Proposed first deadline for required
                                annual prescribed burning activity data.
Within 30 days, or longer as   Proposed timing for States to report
 provided by EPA.               nonpoint tool inputs during the year of
                                the inventory and the year after (e.g.,
                                during 2023 and 2024 for the 2023
                                triennial inventory year).
Within 60 days, or longer as   Proposed timing for States to report
 provided by EPA.               nonpoint emissions data for nonpoint
                                sources with EPA tools (e.g., during
                                2023 and 2024 for the 2023 triennial
                                inventory year).
------------------------------------------------------------------------
                       Dates for owners/operators
------------------------------------------------------------------------
10/31/2024...................  Proposed deadline for the ``One-time
                                Collection Option'' for HEDD-related
                                small generating units (if this option
                                were selected for the final rule).
5/31/2025....................  Proposed deadline for voluntary reporting
                                by owners/operators (for the 2024
                                inventory year).
5/31/2026....................  Proposed deadline for owners/operators
                                with point sources within Indian country
                                not reported by tribes to report CAP and
                                HAP (for the 2025 inventory year). Also,
                                the deadline for voluntary reporting by
                                other owners/operators.
5/31/2027....................  Proposed first deadline for all owners/
                                operators to report HAP for 2026
                                reporting year.
3/31/2028....................  First earlier proposed deadline for
                                owners/operators to report for the 2030
                                reporting year.
To meet Federal or State       Source test/performance test collection.
 testing requirement or
 otherwise within 60 days
 after completing testing.
------------------------------------------------------------------------

T. Summary of Regulatory Impact Analysis

    In this preamble section, we briefly summarize the costs and 
benefits of this proposal. The RIA for this proposed rule provides 
additional detail on these costs and benefits.\79\ The EPA encourages 
commenters to provide any additional information not considered in the 
RIA for this proposed rule or to provide comments on EPA's cost 
estimation approaches.
---------------------------------------------------------------------------

    \79\ The RIA is available through the docket for this action.
---------------------------------------------------------------------------

    While methodological limitations prevented the EPA from monetizing 
the potential human health and environmental benefits, given that no 
changes in emissions or other environmental effects can currently be 
estimated that may be directly attributed to the greater availability 
and quality of emissions data, and in particular HAP emissions, we 
present a qualitative discussion of benefits. These benefits include 
those to communities that may be particularly impacted by pollutant 
emissions, whether they be HAP or CAP.
    The benefits of the proposed revisions to the AERR of collecting 
additional HAP, CAPs, controls, and sub-facility data include improved 
understanding, awareness, and decision making related to the provision 
and distribution of information. The information shared with EPA, and 
incorporated into the NEI, could enable the public to make

[[Page 54194]]

more informed decisions on where to live and work, strengthen the 
public's ability to adequately protect themselves from potential harm 
from criteria air pollutants and air toxics, and provide a greater 
capacity for meaningful involvement in the development and 
implementation of local pollution management policies.
    This proposed action would ensure that communities have the data 
needed to understand significant sources of air pollution that may be 
impacting them and address existing environmental justice issues that 
are discussed previously in this preamble. Additional benefits to these 
communities include building public confidence through clear and 
transparent emission measures and reports and the ability of the public 
to better make facilities accountable for their emissions. Availability 
of increased information on HAP emissions can also be used to advance 
the Agency's environmental justice goals by increasing the 
understanding of the potential impacts of air toxics emissions from 
regulated facilities on minority and disadvantaged communities who have 
been historically burdened by often difficult to detect and undisclosed 
pollution that is experienced on a regular basis. The required 
reporting of HAP emissions data will increase EPA's ability to 
accurately conduct technology reviews pursuant to CAA section 
112(d)(6), and risk reviews under CAA section 112(f)(2), which should 
lead to future regulation of HAP that will be more effective in 
reducing the burden of exposure of such emissions from what has 
occurred in the past. These provisions are additionally informed by 
Federal policy on environmental justice, including Executive Order 
12898, which overlays environmental justice considerations for the EPA 
to assess as part of such work. Even for owners/operators who also must 
report emissions to the TRI program, this proposed action would 
require_additional sub-facility details necessary for air quality 
modeling that, in turn, would allow the EPA and other authorities to 
assess local-scale community impacts and devise solutions for high-risk 
areas.
    The proposed amendments would ensure HAP emissions data are 
collected_consistently for all communities across the country. 
Currently, the availability and detail of HAP emissions data varies 
across States, which creates a situation where some communities have 
incomplete or less accurate information than others, while still facing 
the same or greater_potential risks. Transparent, public data on 
emissions allows for accountability of polluters to the public 
stakeholders, including communities, that bear the social cost of the 
pollution.
    Finally, the proposed provision of additional information could 
also lead to behavioral changes that could result in additional 
benefits. In particular, voluntary initiatives by facilities to review 
emissions control management practices and facility processes, set 
goals for reductions in emissions, and institute ``good neighbor'' 
policies may result from provision of additional emissions data. 
Potential changes in facility operations, such as reductions in 
pollutant releases, could yield health and environmental benefits. 
There may be instances where pollutant emissions are themselves 
valuable product from a market standpoint (e.g., natural gas, that 
includes HAP and methane, leaking from a pipeline), and their control 
or capture may not only be beneficial to the environmental but also 
beneficial to the firms that own the natural gas. While behavioral 
changes from the provision of information may result from the rule and 
are, in fact, one goal of these types of policies, they are not 
mandated by the proposed action. The reporting of such emission data, 
and its public disclosure, may provide social benefits in itself since 
this data disclosure may incentivize emission reductions.
    Regarding the costs of this proposal, the proposed rule's cost to 
State, local, Tribal government authorities is estimated at $28.5 
million on average annually from 2024 to 2026, and then is estimated at 
$27.7 million in 2027. For owners and operators of affected sources, 
the proposed rule's cost is estimated at $89.0 million on average 
annually from 2024 to 2026, and then is estimated at $450.1 million in 
2027. Thus, the proposed rule's total cost impact is estimated at 
$117.4 million on average annually from 2024 to 2026, and then is 
estimated at $477.9 million in 2027. All of these costs are in 2021 
dollars. The increase in costs for owners and operators of affected 
sources in 2027 reflects full implementation of the proposed rule if 
finalized for the entire population of affected sources.
    Regarding the population of affected sources for the 2024-2026 time 
period, the EPA estimates the proposed rule would impact 85 State/
local/Tribal respondents and 820 owners/operators of facilities outside 
of States' implementation planning authority. Owners/operators for an 
estimated 40,315 facilities per year would also need to prepare for new 
reporting requirements starting in 2027. Also, during this period, the 
EPA estimates that owners/operators of 13,420 facilities would report 
source test and performance evaluation data each year. Based on these 
proposed requirements, States would continue to collect emissions data 
from owners/operators of an estimated 13,420 facilities (based on State 
regulations requiring owners/operators to do so). Starting in 2027, the 
EPA estimates that, under the proposed AERR, owners/operators from 
about 129,490 facilities would be required to report HAP as would about 
235 owners/operators for reporting small generating unit data. More 
information on the costs and estimates of affected facilities can be 
found in the ICR supporting statement and the RIA for this proposal, 
located in the docket for this action.
    In addition, as part of fulfilling analytical guidance with respect 
to E.O. 12866, EPA presents estimates of the present value (PV) of the 
social costs of the proposal over the period 2024 to 2033, an 
analytical timeline that is approximately the first 10 years after this 
rule is finalized as proposed. To calculate the present value of the 
social costs of the proposed rule, annual costs are discounted to 2023 
at 3 percent and 7 discount rates as directed by OMB's Circular A-4. 
The EPA also presents the equivalent annualized value (EAV), which 
represents a flow of constant annual values that, had they occurred in 
each year from 2024 to 2033, would yield a sum equivalent to the PV. 
The EAV represents the value of a typical cost or benefit for each year 
of the analysis, consistent with the estimate of the PV, in contrast to 
the year-specific estimates mentioned earlier in the RIA. The PV of the 
compliance costs, in 2021 dollars and discounted to 2023, is $2.41 
billion when using a 7 percent discount rate and $3.06 billion when 
using a 3 percent discount rate. The EAV, an estimate of the annualized 
value of the costs consistent with the present values, is $343 million 
when using a 7 percent discount rate and $358 million when using a 3 
percent discount rate. Table 6 summarizes the costs and benefits of 
this proposal.

[[Page 54195]]



   Table 6--Summary of Benefits, Costs and Net Benefits for the Proposal From 2024 to 2033, Discounted to 2023
                                                [Million 2021$ a]
----------------------------------------------------------------------------------------------------------------
                                                                         Proposal impacts
                                                 ---------------------------------------------------------------
                                                             3 Percent                       7 Percent
                                                 ---------------------------------------------------------------
                                                        PV              EAV             PV              EAV
----------------------------------------------------------------------------------------------------------------
Total Monetized Benefits \a\....................                N/A
                                                                N/A
                                                 ---------------------------------------------------------------
Total Costs.....................................          $3,057            $358          $2,410            $343
                                                 ---------------------------------------------------------------
Net Benefits....................................                N/A
                                                                N/A
                                                 ---------------------------------------------------------------
Non-Monetized Benefits..........................  Improved emissions data access for State, local, and tribal
                                                  government agencies.
                                                  Increased emissions data for addressing local (environmental
                                                  justice) issues.
                                                  Better data to inform regulatory decision making
                                                  Increased emissions data to incentivize voluntary emission
                                                  reduction efforts by industry and others.
----------------------------------------------------------------------------------------------------------------
\a\ We have determined that quantification of benefits cannot be accomplished for this proposed rule. This is
  not to imply that there are no benefits of the proposal; rather, it is a reflection of the difficulties in
  monetizing the benefits for the listed categories with the data currently available. N/A = not available.

    These cost estimates include those for impacts to State, local, and 
Tribal organizations that are engaging in voluntary activities that 
would become codified as a result of this proposal if finalized. The 
EPA has broken out those costs separately and provides discussion of 
them in the RIA for this proposal. Similarly, we acknowledge that the 
cost estimates for this proposal include those for revisions to SIP 
planning activities, and we also break out these costs separately and 
provide discussion of them in the RIA for this proposal.

V. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulations and Regulatory Review

    This action is a ``significant regulatory action,'' as defined 
under section 3(f)(1) of Executive Order 12866, as amended by Executive 
Order 14094. Accordingly, EPA, submitted this action to the Office of 
Management and Budget (OMB) for Executive Order 12866 review. 
Documentation of any changes made in response to the Executive Order 
12866 review is available in the docket. The EPA prepared an analysis 
of the potential costs and benefits associated with this action. This 
analysis, ``Regulatory Impact Analysis for the Proposed Revisions to 
the Air Emissions Reporting Requirements,'' is also available in the 
docket and is briefly summarized in section IV.T of this preamble.

B. Paperwork Reduction Act

    The information collection activities in this proposed rule have 
been submitted for approval to the Office of Management and Budget 
(OMB) under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The 
draft Information Collection Request (ICR) document prepared by the EPA 
has been assigned the EPA ICR number 2170.09. You can find a copy of 
the ICR in the docket for this rule, and it is briefly summarized here.
    In past years, the information collection under the existing AERR 
has coordinated the various State emission inventory reporting 
requirements and has streamlined the activities involved in submitting 
certain emissions data to the EPA. The proposed revisions to the 
collection would (1) continue this coordination to enable the EPA to 
achieve uniformity and completeness in a national inventory to support 
national, regional, and local air quality planning and attainment of 
NAAQS and planning needed for meeting regional haze requirements, (2) 
greatly improve HAP data collections that are voluntary under the 
existing AERR, but are proposed herein to become mandatory (3) fill 
other identified gaps in emissions inventories for sources within 
Indian country, for certain small generation units, and for prescribed 
fires nationally, and (4) greatly improve the availability of data 
necessary for creating emissions factors.
    The draft ICR for this proposed action includes collection of both 
mandatory and voluntary data from States (as defined in section III to 
include certain local and tribal governments) for annual and more 
extensive triennial collections of emissions data. The draft ICR also 
covers the proposed collection of mandatory and voluntary data from 
owners/operators that emit emissions at or above proposed reporting 
thresholds and that perform source tests. While the focus of the draft 
ICR is the 2024-2026 period, additional costs from 2027 and beyond are 
included in Appendix A of the draft ICR to reflect additional costs 
associated with full implementation of the proposed revisions.
    Respondents/affected entities: For the 2024-2026 period covered by 
the draft ICR, the EPA estimates the proposed rule would impact 85 
State/local/Tribal respondents and 813 owners/operators of facilities 
outside States' implementation planning authority. Also, during this 
period, the EPA estimates that owners/operators of 13,420 facilities 
would report source test and performance evaluation data each year and 
120,945 facilities (40,315 per year) would collect release point 
latitude/longitude data for reporting in 2027. Based on these proposed 
requirements, States would continue to collect emissions data from 
owners/operators of an estimated 13,420 facilities (based on State 
regulations requiring owners/operators to do so). Starting in 2027, 
Appendix A of the draft ICR identifies owners/operators of an estimated 
129,500 facilities from which this proposed rule would require HAP 
reporting and for about 235 owners/operators, reporting of small 
generation unit data.

[[Page 54196]]

    Respondent's obligation to respond: Under this proposed action, the 
EPA estimates that 85 governmental entities would be required to report 
to EPA. Authority for such collection is provided by CAA sections 110, 
114, 172, 182, 187, 189, and 301(a). In addition, owners/operators 
would be required to report data to EPA, and authority for these 
collections is provided by the same CAA sections. Additionally, 7 
railroad companies are expected to voluntarily provide data to the EPA 
once every three years but would be under no obligation to do so.
    Estimated number of respondents: During the 2024-2026 period, the 
EPA expects 85 governmental entities, owners/operators from an 
estimated 14,233 facilities (13,420 to States and 819 to EPA), and 
owners/operators of 7 railroads to respond. The description above 
provides additional detail on the numbers and types of respondents for 
the draft ICR period and for subsequent periods.
    Frequency of response: States would submit emissions data annually, 
with more data required every third year. Owners/operators of 
facilities within Indian country would report each year, starting in 
2026 (for the 2025 emissions inventory year). The frequency of source 
test data reports depends on the testing requirements set by the EPA 
and States. Frequency can range from several times per year to once 
every several years. However, for the purpose of the draft ICR, the EPA 
estimates that owners/operators reporting source test data would report 
an average of 3 source tests per year. Starting in 2027, the States and 
owners/operators of facilities affected by this proposed rule would 
report the same amount of point source data every year. Also starting 
in 2027, States would report prescribed burning data each year. No 
change is being proposed to triennial reporting frequency for nonpoint 
and mobile sources.
    Total estimated burden: All burden estimates include additional 
burden associated with proposed options included in the preamble (or 
the most costly option when multiple options are described). Table 6 
includes total estimated burden split by respondent, activity, and 
mandatory or voluntary activities. Total estimated burden for all 
entities combined is 1,142,927 hours for mandatory activities and 
99,115 for voluntary hours during the 3-year period of this ICR. Of 
this, the estimated burden for States is 317,454 hours for mandatory 
activities and 99,087 for voluntary activities. Estimated burden for 
owners/operators is 825,473 hours for mandatory activities and 28 hours 
for voluntary activities. Burden is defined at 5 CFR 1320.3(b).
BILLING CODE 6560-50-P

[[Page 54197]]

[GRAPHIC] [TIFF OMITTED] TP09AU23.035

BILLING CODE 6560-50-C
    The draft ICR additionally provides, via Appendix C, State and 
owner/operator hours and costs associated with emissions data 
activities for SIP preparation, in compliance with OMB expectations 
that the EPA include those costs. Since those costs are not burden 
associated with the proposed revisions to the AERR, they are not 
included in Table 6, but are noted here as EPA

[[Page 54198]]

requests comment on the burden estimates.
    Total estimated cost: Annual capital or operation & maintenance 
costs include costs for the EPA and States. The EPA's expected annual 
capital costs for its data systems needed from 2024 through 2026 are 
$600,000. EPA's additional annual system development, operations, and 
maintenance costs are expected to be $3,625,000. States' total 
annualized capital costs are estimated to be $127,500, and their 
operation and maintenance costs about $10,156,000.
    An agency may not conduct or sponsor, and a person is not required 
to respond to a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR part 51 are listed in 40 CFR part 9.
    Submit your comments on the agency's need for this information, the 
accuracy of the provided burden estimates, and any suggested methods 
for minimizing respondent burden to the EPA using the docket identified 
at the beginning of this rule. You may also send your ICR-related 
comments to OMB's Office of Information and Regulatory Affairs via 
email to [email protected], Attention: Desk Officer for EPA. 
Since OMB is required to make a decision concerning the ICR between 30 
and 60 days after receipt, OMB must receive comments no later than 
September 8, 2023. The EPA will respond to any ICR-related comments in 
the final rule.

C. Regulatory Flexibility Act

    Pursuant to Section 603 of the RFA, the EPA prepared an initial 
regulatory flexibility analysis (IRFA) that examined the impact of the 
proposed rule on small entities along with regulatory alternatives that 
could minimize that impact. The complete IRFA is available for review 
in the docket (see Chapter 4 of the RIA in the docket for this 
proposal) and is summarized here. The EPA is soliciting comment on the 
presentation of its analysis of the impacts on small entities. As 
required by Section 604 of the RFA, the EPA will prepare a final 
regulatory flexibility analysis (FRFA) for this action as part of the 
final rule. The FRFA will address the issues raised by public comments 
on the IRFA.
    EPA is considering this proposal to fill gaps in the existing 
available emissions inventory data, most notably for HAPs, prescribed 
burning, and small generation units related to HEDD events. The HAP 
data collection supports improved understanding of pollutants 
surrounding at-risk communities. Additionally, the proposed revisions 
to the AERR would further streamline air emissions reporting, allow for 
improved consistency of emissions calculation methods, quality, and 
transparency of state-provided data.
    Through this proposal, the EPA will have improved emissions data on 
which to make decisions affecting implementation of the Clean Air Act 
for both the air toxics program and the NAAQS. As described in section 
III of this proposal, the EPA is proposing these amendments pursuant to 
its authority under CAA sections 110, 111, 112, 113, 114, 129, 172, 
182, 187, 189, and 301 (see also section III of this proposal). 
Further, EPA's proposed action supports better understanding of 
pollution to inform the EPA as it works to include environmental 
justice considerations as described by E.O. 12898 (see also section 
IV.A.1 of this preamble).
    EPA estimates that small entities will be affected by this proposal 
when they are major sources, and for non-major sources, have primary 
NAICS as listed in section II of this proposal. The EPA estimates that 
approximately 34,800 small entities could be impacted by this rule 
based on the CAA definition that the EPA proposes to use for this rule. 
That number would increase to approximately 44,600 if the EPA were to 
use the SBA definition.
    Based on this proposal, affected small entities would need to 
report unit-level information about their facilities and report 
facility-wide emissions in most circumstances. The small business 
accommodation that this proposal offers to small businesses to report 
with less detail could be eliminated for certain facilities if data 
submitted in past inventory years shows, through EPA modeling, an 
unacceptable level of risk. Small entities will need to be able to 
record basic information about their facility such as fuel consumed by 
certain activities, electricity used, amount of solvents consumed, 
amount of product produced, or number of employees. Small entities will 
additionally need to be able to enter this information in electronic 
forms.
    The EPA has reviewed other EPA emissions reporting requirements for 
duplication and is aware of the potential for duplication of limited 
data elements for certain other EPA collections, though it is not aware 
of any collection that is wholly or significantly duplicative. Further, 
the EPA is actively working to avoid this duplication with its CAERS 
development efforts. These potentially duplicative requirements include 
40 CFR parts 75, 98, and 372. The EPA requests comment on whether this 
list is comprehensive.
    EPA is considering a number of alternatives in this proposed rule 
to minimize any significant economic impact of the proposed rule on 
small entities. These proposed approaches are described in sections 
IV.A.12 through IV.A.14 of this preamble. The EPA has included various 
accommodations for small entities in the proposed rule based on 
recommendations from the SBAR Panel Report, and these are additionally 
reflected in the IRFA and proposed ICR.
    As required by Section 609(b) of the RFA, the EPA also convened a 
Small Business Advocacy Review (SBAR) Panel to obtain advice and 
recommendations from small entity representatives that potentially 
would be subject to the rule's requirements. The SBAR Panel evaluated 
the assembled materials and small-entity comments on issues related to 
elements of an IRFA. A copy of the full SBAR Panel Report is available 
in the rulemaking docket.

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more for State, local, or tribal governments as described in UMRA, 2 
U.S.C. 1531-1538, and does not significantly or uniquely affect small 
governments. This action does contain unfunded Federal mandates under 
UMRA that may result in annual expenditures of $100 million or more for 
the private sector. Accordingly, the costs and benefits associated with 
this action are discussed in section IV.T of this preamble and in the 
RIA, which is in the docket for this rule.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action has Tribal implications. However, it will neither 
impose substantial direct compliance costs on federally recognized 
Tribal governments, nor preempt Tribal law, and does not have 
substantial direct effects on the relationship between the Federal 
Government and Indian Tribes or on the distribution of power and 
responsibilities between the Federal Government and Indian Tribes, as 
specified in E.O. 13175. 65 FR 67249

[[Page 54199]]

(November 9, 2000). Consistent with the EPA Policy on Consultation and 
Coordination with Indian Tribes, the EPA will provide Tribal officials 
the opportunity to provide meaningful and timely input through 
government-to-government consultation during the development of this 
action. The majority of the facilities within Indian country expected 
to be affected by this proposed action are owned by private entities. 
For point sources, there would only be Tribal implications associated 
with this rulemaking in the case where a unit is owned by a Tribal 
government. The EPA notes that the reporting requirements for emissions 
data proposed are unlikely to impose substantial costs. For nonpoint 
sources, there would be Tribal implications for the proposed 
requirements for how Tribes should report nonpoint emissions when 
overlapping more than a single county within a State. Further, Tribal 
implications may exist for the proposed provision that directs States 
to include complete nonpoint source activity, inclusive of activity 
within Indian country, when tribes overlapping State boundaries are not 
required to report or optionally report nonpoint data to EPA.

G. Executive Order 13045: Protection of Children From Environmental 
Health and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. This action is not subject to 
Executive Order 13045 because it does not concern an environmental 
health risk or safety risk.

H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution or use of energy. Further, we have concluded that this 
action is not likely to have any adverse energy effects because the 
requirements to report emission data under this proposed action are 
either already being met as part of the current AERR or would be a 
small incremental impact on regulatory requirements for any facility 
required to report emission data under this action. The EPA does not 
anticipate that the provision described in section IV.D to collect 
daily fuel usage data from States for sources with intermittent 
electric generation would have any significant impact on the deployment 
of such sources.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs 
federal agencies, to the greatest extent practicable and permitted by 
law, to make environmental justice part of their mission by identifying 
and addressing, as appropriate, disproportionately high and adverse 
human health or environmental effects of their programs, policies, and 
activities on communities with environmental justice concerns.
    The EPA believes that this type of action does not concern human 
health or environmental conditions and, therefore, cannot be evaluated 
with respect to potentially disproportionate and adverse effects on 
communities with environmental justice concerns. This action would 
update reporting requirements for State, local, and tribal entities and 
add new reporting requirement for facilities for the collection of air 
emissions data that are used to inform EPA's technical analysis of 
impacts on human health and the environment.

K. Determinations Under CAA Section 307(b)(1) and (d)

    Section 307(b)(1) of the CAA governs judicial review of final 
actions by the EPA. This section provides, in part, that petitions for 
review must be filed only in the United States Court of Appeals for the 
District of Columbia Circuit: (i) When the agency action consists of '' 
any other nationally applicable regulations promulgated, or final 
action taken, by the Administrator,'' or (ii) when such action is 
locally or regionally applicable but ``such action is based on a 
determination of nationwide scope or effect and if in taking such 
action the Administrator finds and publishes that such action is based 
on such a determination.'' The CAA reserves to the EPA complete 
discretion to decide whether to invoke the exception in (ii) described 
in the preceding sentence.\80\
---------------------------------------------------------------------------

    \80\ Sierra Club v. EPA, 47 F.4th 738, 745 (D.C. Cir. 2022) 
(``EPA's decision whether to make and publish a finding of 
nationwide scope or effect is committed to the Agency's discretion 
and thus is unreviewable''); Texas v. EPA, 983 F.3d 826, 834-35 (5th 
Cir. 2020).
---------------------------------------------------------------------------

    This proposed action, if finalized, would be ``nationally 
applicable'' within the meaning of CAA Section 307(b)(1). In the 
alternative, to the extent a court finds the action to be locally or 
regionally applicable, the Administrator intends to exercise the 
complete discretion afforded to him under the CAA to make and publish a 
finding that the action is based on a determination of ``nationwide 
scope or effect'' within the meaning of CAA Section 307(b)(1).\81\
---------------------------------------------------------------------------

    \81\ In deciding whether to invoke the exception by making and 
publishing a finding that this action, if finalized, is based on a 
determination of nationwide scope or effect, the Administrator 
intends to take into account a number of policy considerations, 
including his judgment balancing the benefit of obtaining the D.C. 
Circuit's authoritative centralized review versus allowing 
development of the issue in other contexts and the best use of 
agency resources.
---------------------------------------------------------------------------

    This proposed action, if finalized, would implement a national 
emissions data collection program in all 50 States, the District of 
Columbia, U.S. territories, and Indian country, a geographic area that 
spans all 10 EPA regions and 12 Federal judicial circuits. The proposed 
action applies a uniform, nationwide approach to data collection and 
interpretation of the various CAA provision discussed in this preamble 
across all of these areas, and the proposed rule is based on a common 
core of legal, technical, and policy determinations (as explained in 
further detail in the following paragraph). For these reasons, this 
proposed action, if finalized, would be nationally applicable.
    Alternatively, to the extent a court finds this proposal, if 
finalized, to be locally or regionally applicable, the Administrator 
intends to exercise the complete discretion afforded to him under the 
CAA to make and publish a finding that the action is based on one or 
more determinations of nationwide scope or effect for purposes of CAA 
Section 307(b)(1).\82\ Specifically, the proposed rule is based on a 
common core of statutory analysis, factual findings, and policy 
determinations concerning the collection of emissions data from State, 
local, and tribal agencies nationwide and from owners/operators of 
emission sources located in those States, territories, and Indian 
country. In addition, the technical, scientific, and engineering 
information in support of the proposed emissions data collection 
requirements relies on a

[[Page 54200]]

nationally consistent modeling methodology to set emissions reporting 
thresholds, as set forth elsewhere in this proposed rule and in the 
relevant supporting documents in the docket for this proposed rule.
---------------------------------------------------------------------------

    \82\ In the report on the 1977 Amendments that revised section 
307(b)(1) of the CAA, Congress noted that the Administrator's 
determination that the ``nationwide scope or effect'' exception 
applies would be appropriate for any action that has a scope or 
effect beyond a single judicial circuit. See H.R. Rep. No. 95-294 at 
323, 324, reprinted in 1977 U.S.C.C.A.N. 1402-03.
---------------------------------------------------------------------------

    Therefore, pursuant to CAA section 307(b), any petitions for review 
of this action, if and when it is finalized, must be filed in the D.C. 
Circuit within 60 days from the date such final action is published in 
the Federal Register.
    In addition, pursuant to CAA section 307(d)(1)(V), the EPA hereby 
determines that this rulemaking action is subject to the requirements 
of section 307(d).

List of Subjects

40 CFR Part 2

    Environmental protection, Emission data, Administrative practice 
and procedure, Confidential business information, Courts, Freedom of 
information, Government employees.

40 CFR Part 51

    Environmental Protection, Administrative practice and procedure, 
Air pollution control, Emission data, Intergovernmental relations, 
Criteria pollutants, Hazardous Air Pollutants, Ozone, Particulate 
matter, Oxides of Nitrogen, Sulfur dioxide, Lead, Regional haze, 
Reporting and record keeping requirements, Stationary sources, Mobile 
sources, Prescribed fires.

Michael S. Regan,
Administrator.

    For the reasons stated in the preamble, title 40, chapter I, Part 2 
of the Code of Federal Regulations is proposed to be amended and Part 
51 is proposed to be revised as follows:

PART 2--[AMENDED]

0
1. The authority for part 2 continues to read as follows:

    Authority:  5 U.S.C. 552, 552a, 553; 28 U.S.C. 509, 510, 534; 31 
U.S.C. 3717.

Subpart A--Procedures for Disclosure of Records Under the Freedom 
of Information Act

0
2. Amend Sec.  2.301 by adding paragraph (k) to read as follows.


Sec.  2.301  Special rules governing certain information obtained under 
the Clean Air Act.

* * * * *
    (k) Data submitted under 40 CFR part 51, subpart A.
    (1) Sections 2.201 through 2.215 do not apply to data submitted 
under 40 CFR part 51, subpart A that the EPA has determined, pursuant 
to 42 U.S.C. 7414 in a rulemaking subject to 42 U.S.C. 7607(d), to be 
emission data as defined in paragraph (a)(2)(i) of this section.
    (2) The provisions of 40 CFR 2.201 through 2.215 continue to apply 
for categories of reported information identified in 40 CFR part 51, 
subpart A for which there is no emission data determination in 40 CFR 
part 51, subpart A.

PART 51--[AMENDED]

0
3. The Authority citation for part 51 continues to read as follows:

    Authority:  23 U.S.C. 101; 42 U.S.C. 7401-7671q.

0
4. Subpart A of part 51 is revised to read as follows:

Subpart A--Air Emissions Reporting Requirements

    General Information for Inventory Preparers


Sec.  51.1  Who is responsible for what actions described in this 
subpart?

    Both States \1\ and certain owners/operators of facilities emitting 
``air pollutants'' (as defined by Sec.  51.50 of this subpart) are 
subject to requirements included in this section.
---------------------------------------------------------------------------

    \1\ The term ``State'' is defined to include delegated local 
agencies and tribes that have elected to seek treatment in the same 
manner as a state (TAS) status and have obtained approval to 
implement rules such as the AERR through a Tribal Implementation 
Plan (TIP).
---------------------------------------------------------------------------

    (a) Owners and operators of facilities.
    (1) An owner/operator of a point source within a State's 
implementation planning authority must report emissions data as 
described by Sec.  51.25 of this subpart.
    (2) An owner/operator of a point source that is outside the 
geographic scope of a State's implementation planning authority must 
report emissions data as described by Sec.  51.27 of this subpart. This 
could include owners/operators of facilities located within certain 
portions of Indian country, owners/operators of (1) deepwater ports 
subject to CAA requirements under the Deepwater Port Act, and (2) 
owners/operators of OCS sources as defined in CAA section 328(a) with 
the exception of owners/operators of facilities that are regulated 
under 43 U.S.C. 1331 et seq. (the Outer Continental Shelf Lands Act) 
and that are located (a) offshore of the North Slope Borough of the 
State of Alaska, or (b) offshore of the United States Gulf Coast 
westward of longitude 87 degrees and 30 minutes.
    (3) An owner/operator of a point source that collects source test 
data or performance evaluations may need to report that data as 
described by Sec. Sec.  51.25 and 51.27 of this subpart.
    (4) If the owner and operator of a facility are different parties, 
only one party needs to report under this subpart.
    (b) Indian tribes with Treatment as a State status. An Indian tribe 
(as defined by CAA section 302(r)) may elect to seek Treatment as State 
(TAS) status as prescribed by the Tribal Authority Rule 40 CFR part 49, 
subpart A. An Indian tribe may obtain approval to implement reporting 
for this subpart through a Tribal Implementation Plan (TIP), but Indian 
tribes are under no obligation to do so. Those Indian Tribes that have 
obtained TAS status are subject to this subpart to the extent allowed 
in their TIP. Accordingly, for an Indian Tribe that has applied for and 
received TAS status for air quality control purposes and is subject to 
the AERR under its TIP, the use of the term state in this subpart 
should be read to include that tribal government.
    (c) State mandatory reporting.
    (1) A State must collect and report to the EPA criteria pollutant 
and precursor emissions data from point sources (as defined by Sec.  
51.50 of this subpart) as described by Sec.  51.15(a) of this subpart. 
A State must collect and report data for all such sources within the 
State's implementation planning authority, including any offshore areas 
within State waters or within any Federal waters for which a State 
agency has delegated authority. A lack of State permitting for point 
sources or pollutants associated with them does not exempt a facility 
or pollutant from being reported.
    (2) A State must report to the EPA data from airports as described 
by Sec.  51.15(b) of this subpart.
    (3) A State must report to the EPA rail yard data as described by 
Sec.  51.15(c) of this subpart.
    (4) A State must report to the EPA nonpoint source data as 
described by Sec.  51.15(d) of this subpart.
    (5) A State must report to the EPA mobile source data as described 
by Sec.  51.15(e) of this subpart.
    (6) A State must report data about certain prescribed burning (as 
defined by 40 CFR 51.301) to the EPA (as described by Sec.  51.15(f) of 
this subpart) for those prescribed burns that meet the following 
criteria:
    (i) The prescribed burn is not an agricultural burn or a land 
clearance burn (as defined by Sec.  51.50 of this subpart); and
    (ii) The prescribed burn occurs on State lands or military lands, 
excluding prescribed burns on such lands conducted by Federal Land 
Managers (as defined by CAA 302(i)); and

[[Page 54201]]

    (iii) The prescribed burn is one of the following:
    (A) A broadcast burn or understory burn that impacts at least 50 
acres; and/or
    (B) A pile burn that includes biomass from at least 25 acres; and/
or
    (C) A prescribed burn that includes pile burning as well as other 
prescribed burn types that in total collects biomass from or burns at 
least 25 acres.
    (7) EPA urges State environmental agencies to coordinate with State 
forestry agencies to collect, obtain, and report the data described by 
Sec.  51.1(c)(6). A lack of State permitting requirements or other 
planning processes does not exempt a prescribed burn from being 
reported.
    (d) State optional reporting.
    (1) For inventory years 2026 and later, a State that intends to 
collect and report hazardous air pollutants (HAP) on behalf of owners/
operators for a given emissions inventory year must:
    (i) Promulgate a State regulation to collect facility inventory and 
actual annual emissions data for HAP to meet the requirements for 
owners/operators by:
    (A) Replicating requirements on owners/operators from Sec.  51.5 of 
this subpart, excluding paragraphs Sec.  51.5(h) and (i);
    (B) Ensuring the definition of point sources is consistent with 
Sec.  51.50 of this subpart;
    (C) Ensuring reporting of all HAP as described by Sec.  51.12(b) of 
this subpart and requirements for specific situations described by 
Sec.  51.12(d) and (e) of this subpart;
    (D) Ensuring reporting of incidental criteria pollutants and 
precursors as described by Sec.  51.12(c) of this subpart;
    (E) Including the timing for point source reporting from owners/
operators to the State as described by Sec.  51.30 of this subpart; and
    (F) Ensuring reporting of all required data elements as described 
by Sec.  51.40(a) and (b) of this subpart.
    (ii) Apply to the EPA in writing by March 31 of the first inventory 
year for which the State intends to report emissions data for HAP 
(e.g., for the 2026 emissions inventory year, a State must apply by 
March 31, 2026) by providing citations to the State regulation for each 
of the elements listed in Sec.  51.1(d)(1)(i).
    (2) The EPA will notify a State as expeditiously as possible 
regarding its application, any needed adjustments, and post final 
approval decisions on the EPA Air Emissions Inventories website 
(https://epa.gov/air-emissions-inventories) for use by the State and 
owners/operators.
    (3) A State must reapply for HAP reporting approval when one or 
more of the following events occurs:
    (i) The State changes its emissions inventory reporting 
requirements related to any aspect of the application requirements 
described by Sec.  51.1(d)(1)(i) of this subpart.
    (ii) EPA revises requirements of this subpart for pollutants 
described by Sec.  51.12 (b) through (e) of this subpart, HAP reporting 
thresholds (for which the initial reporting thresholds are presented in 
Table 1B to Appendix A of this subpart) or the associated required data 
elements as described by Sec.  51.40.
    (iii) The EPA notifies a State in writing that a new application is 
required for any reason, including that the State failed to meet any 
requirement of this subpart.
    (4) If a State intends to use or integrate with the Combined Air 
Emissions Reporting System (CAERS) for a particular inventory year, the 
State should notify the EPA of this intent by two months prior to start 
of the inventory year (e.g., for the 2024 inventory year, a State 
should notify the EPA by November 1, 2023).
    (5) If a State intends to stop collecting and reporting HAP for 
point sources, the State must notify the EPA in writing by November 1 
of the year prior to the inventory year (e.g., for the 2024 inventory 
year, a State must notify the EPA by November 1, 2023).
    (6) The EPA approval for a State to report HAP remains effective 
for subsequent inventory years until the EPA revokes that approval and 
transfers responsibility back to owners/operators.
    (e) The State (as defined by CAA section 302(d)) may authorize a 
municipality (as defined by CAA section 302(f)) to fulfill the data 
collection and reporting requirements of this subpart on behalf of the 
State and to submit data to the EPA for emissions within that 
municipality's authority. Such authorization does not relieve the State 
of responsibility for carrying out the applicable requirements of this 
subpart. Accordingly, for municipalities that have obtained authority 
to collect and report under this subpart, the use of the term ``State'' 
in this subpart should be read to include that municipality.


Sec.  51.5  What data, tools and other considerations apply for 
emissions reporting?

    The requirements in this section are effective starting with 
different inventory years, as follows: Paragraphs (b) through (f) of 
this section are effective starting with the 2026 inventory year. All 
other paragraphs are effective starting with the 2023 inventory year.
    (a) A State or owner/operator must estimate annual actual emissions 
as defined in Sec.  51.50 of this subpart using the best available 
estimation methods for assessing whether its facility emissions exceed 
the emissions reporting thresholds in Tables 1A and 1B to Appendix A of 
this subpart and for submitting point source emissions data under this 
subpart. The ``Introduction to the EPA Compilation of Air Pollutant 
Emissions Factors (AP-42)'' \2\ describes many techniques for 
calculating emissions and provides on page 4 a hierarchy of emissions 
estimation methods. For the purposes of this subpart, a State or owner/
operator should preferentially use available emissions calculation 
methods at the top of the hierarchy over emissions calculation 
approaches lower in the hierarchy. Where current the EPA guidance 
materials are outdated or are not applicable to sources or source 
categories, an owner/operator (other than a small entity, as defined by 
Sec.  51.50 of this subpart) should develop and document new techniques 
for estimating emissions, which should rely on any available source 
measurements applicable to the emissions source(s).
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    \2\ https://epa.gov/air-emissions-factors-and-quantification/ap-42-compilation-air-emissions-factors.
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    (b) A State or owner/operator must include emissions from mobile 
sources (excluding aircraft and ground support equipment) operating 
primarily within the facility site boundaries of a point source or 
multiple adjacent point sources when assessing whether its facility 
emissions exceed the emissions reporting thresholds in Tables 1A and 1B 
to Appendix A of this subpart and when submitting point source 
emissions data under this subpart.
    (c) An owner/operator submitting emissions data directly to the EPA 
under this subpart must use continuous monitor data applicable to the 
units and processes that operated during the reporting year to 
calculate annual actual emissions. In the absence of monitored data, an 
owner/operator must use the most recent source test(s) applicable to 
the operating conditions of the units and processes during that year to 
estimate annual actual emissions. An owner/operator should determine 
which source test data should be included to best estimate annual 
actual emissions. If a facility has source tests, performance 
evaluations, or continuous emissions monitoring data for a unit or 
process that operated during the reporting year and the owner/operator 
does not use

[[Page 54202]]

that data to estimate annual emissions, then the owner/operator must 
submit a justification for that choice for each unit and pollutant for 
which such data are not used to estimate emissions.
    (d) A State submitting point source emissions on behalf of owners/
operators under this subpart must ensure that owners/operators of 
facilities submitting data to the State take the same approaches as 
described in paragraph Sec.  51.5(a) through (c) of this subpart. If a 
State submits data for an owner/operator who has not used available 
source test data or continuous monitor data to estimate emissions, then 
the State must submit a justification for each unit and pollutant for 
which such data are not used to estimate emissions.
    (e) When source tests, performance tests, or continuous emissions 
monitor data are not available, a State and owner/operator may use 
emission rates from the EPA compilations of emission factors such as 
WebFIRE and AP-42 to estimate emissions. An owner/operator may also use 
emission factors provided by States. To estimate emissions from point 
sources, a State or owner/operator should use emission factors that 
represent the emissions process and controls at the facility. If 
existing emission factors are insufficient for developing 
representative annual actual emissions, a State or owner/operator 
(other than a small entity, as defined by Sec.  51.50 of this subpart) 
should develop new emission factors through emission testing of point 
sources when existing EPA source test methods are available.
    (f) When data described in paragraphs (c), (d), and (e) of this 
section are not available, a State or owner/operator may use the 
SPECIATE database \3\ or other credible, publicly available speciation 
profile data to calculate ratios of related pollutants if relevant 
speciation profiles are available. Starting with the 2026 inventory 
year, when using a speciation profile, a State or owner/operator must 
provide the speciation profile code with their data. When estimating 
emissions using speciation data, the emissions data must include:
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    \3\ SPECIATE Database available at https://epa.gov/air-emissions-modeling/speciate.
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    (1) The most applicable emissions calculation method indicating the 
type of speciation profile used;
    (2) The speciation factor used in the calculation, reported as the 
emission factor;
    (3) The pollutant code that identifies the pollutant used to 
calculate another pollutant, reported as the denominator of the 
emission factor;
    (4) The pollutant code that identifies the pollutant calculated 
from the speciation profile, reported as the numerator of the emission 
factor;
    (5) The emissions value and associated required data elements for 
the pollutant identified in Sec.  51.5(f)(3), reported as an annual 
emissions value even if that pollutant is not otherwise required (e.g., 
Total organic gases); and
    (6) In the case of a SPECIATE profile, the profile code reported as 
the emission factor comment, or in the case of other speciation 
profiles, the journal citation or reference to a publicly available 
report reported as the emission factor comment.
    (g) A State must report data using the Emissions Inventory System 
(EIS) or analogous electronic reporting approach provided by the EPA to 
report data required by this subpart. Submission to the EIS can be done 
using EPA's Central Data Exchange (CDX).\4\ Unless otherwise noted in 
this section, the EPA provides states information about reporting data, 
required and optional data fields, and explains how to access all data 
needed for reporting to EIS as part of a NEI plan available at https://epa.gov/air-emissions-inventories/national-emissions-inventory-nei.
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    \4\ Central Data Exchange is available at https://cdx.epa.gov/.
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    (h) An owner/operator reporting directly to the EPA under this 
subpart must use the Combined Air Emissions Reporting System (CAERS) or 
analogous electric reporting approach provided by the EPA to report 
emissions data. The EPA provides owners/operators information about 
reporting data, required and optional data fields, and explains how to 
access to all data needed for reporting with CAERS at https://epa.gov/air-emissions-inventories.
    (i) An owner/operator reporting directly to the EPA under this 
subpart must use the Compliance and Emissions Data Reporting Interface 
(CEDRI) to report source test data and performance reports as required 
by Sec. Sec.  51.25 and 51.27 or use an analogous electronic reporting 
approach provided by the EPA. CEDRI can be accessed through the CDX.\4\ 
CEDRI works with the EPA's Electronic Reporting Tool (ERT) available 
from EPA's ERT website (https://epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert). A list of test methods, 
performance evaluations, and pollutants compatible with the Electronic 
Reporting Tool (ERT), as well as the date on which those methods or 
performance evaluations were available on the ERT, is available from 
the EPA via the ERT website https://epa.gov/system/files/documents/2021-09/ert-compatible-methods-and-pollutants.pdf).
    (j) A State or owner/operator of point sources reporting under this 
subpart must use the most current data reporting codes for electronic 
reporting that are available at the time of reporting. Reporting codes 
can change over time, and the EPA will strive to publish the EIS 
reporting codes that can be used for each inventory year by June 30 of 
inventory year. For example, the EPA would plan to publish by June 30, 
2024, codes that are to be used for reporting 2024 emissions. Codes are 
published by the EPA as follows:
    (1) Source classification codes (SCCs) can be obtained from the EPA 
SCC website (https://epa.gov/scc). Materials provided on this website 
explain what to do if a SCC is not available for an emissions process; 
and
    (2) Other reporting codes are available through EPA's electronic 
reporting data systems (e.g., EIS and CAERS), and the EPA may make them 
available through references within the NEI plan for each inventory 
year.
    (k) The EPA provides States for their use nonpoint emissions 
calculation methods, associated tools/spreadsheets, and draft activity 
and emissions data for nonpoint sources, point source aircraft, and 
point source rail yards. The nonpoint information includes approaches 
and data based on county totals for commercial marine vessels that are 
treated in this subpart as nonpoint sources for reporting purposes. The 
EPA provides on its Air Emissions Inventories website (https://epa.gov/air-emissions-inventories) an NEI Plan that includes directions for 
which methods, tools, and models should be used and instructions for 
accessing data described in this paragraph.
    (l) The EPA provides the Motor Vehicle Emissions Simulator (MOVES) 
model including quality assurance tools for input data at the MOVES 
website (https://epa.gov/moves). The EPA also provides draft and final 
onroad and nonroad emissions data based on the MOVES model. States, 
except for California, must use MOVES model input formats and the 
quality assurance tools or the same for the latest available on-road 
and nonroad EPA models to meet the requirements of Sec.  51.15(e). The 
model version to be used for a given inventory reporting year will be 
defined in an emissions inventory plan as per paragraph (k).
    (m) For onroad mobile sources, the EPA approves onroad mobile 
models for California for transportation conformity purposes and for 
use in State Implementation Plans (SIPs). For this

[[Page 54203]]

subpart, California must report emissions from onroad mobile sources 
using the latest model version approved by the EPA as of January 1 of 
the emissions inventory year and may optionally use a newer approved 
model. For example, the onroad model approved as of January 1, 2023, 
should be used to estimate and report emissions to meet the 
requirements in Sec.  51.15(e)(3) for the 2023 reporting year, or the 
State could optionally choose to use a model approved by the EPA after 
that date.
    (n) Confidential data/Confidential Business Information (CBI). 
Emissions data are defined by 40 CFR 2.301(a)(2)(i) and are not 
confidential pursuant to 42 U.S.C. 7414(c). The specific data elements 
submitted under this subpart all fall within the definition of 
emissions data and are therefore not entitled to confidential 
treatment. Further, pursuant to 42 U.S.C. 7414(c), the EPA is required 
to make emissions data available to the public. Thus, all data elements 
submitted under this subpart will not be protected as CBI and will be 
made publicly available without further notice to States or the owner/
operator of facilities.
    (o) An owner operator or State reporting on their behalf must 
consider the recommendations and requirements of paragraphs (a) through 
(f), (n), (p), and (q) of this section when:
    (1) Estimating emissions to determine whether a facility's annual 
actual emissions of HAP exceed point source reporting thresholds in 
Table 1B to Appendix A of this subpart; and
    (2) When estimating emissions to report to EPA.
    (p) To estimate emissions for pollutant groups (e.g., ``Lead and 
compounds'' or ``Nickel and compounds''), an owner/operator or a State 
reporting on their behalf should ensure emissions values accurately 
reflect the mass of the metal/toxic portion of the group (Lead or 
Nickel in these examples) by:
    (1) Using emission factors or source test emission rates without 
any adjustments; or
    (2) Accounting for chemical compounds to reflect only the toxic 
portion of the pollutant group when estimating emissions based on 
material balance or engineering judgement; or
    (3) When no other information is available, assuming the entire 
mass of the HAP reported is the toxic portion.
    (q) Some HAP may be measured or have emission factors for a 
pollutant group as well as for individual compounds within the group. 
An owner/operator or a State reporting on their behalf must report the 
most detailed pollutants available preferentially over pollutant 
groups. When the detailed pollutants do not comprise the total mass of 
the pollutant group, the remaining portion of mass for the pollutant 
group must be reported as implemented in the electronic reporting 
approach (as described by Sec.  51.5(g)). Specific compound groups and 
individual pollutants are provided in Tables 1B and 1D to Appendix A of 
this subpart.


Sec.  51.10  What criteria determine when facilities must be reported 
as point sources?

    (a) For point sources (as defined by Sec.  51.50 of this subpart), 
when determining whether emissions data from a facility must be report 
as a point source, States and owners/operators must:
    (1) Include total annual actual emissions from all stack and 
fugitive release points at the facility; and
    (2) Include emissions from mobile sources as described by Sec.  
51.5(b) of this subpart, and in doing so, may exclude emissions from 
aircraft and ground support equipment occuring at the facility.
    (b) For point sources associated with emission inventories required 
by Part 51 Subpart G, Subpart X, Subpart Z, Subpart AA, Subpart CC, 
States must interpret the definition of point sources (as per Sec.  
51.50 of this subpart) as follows:
    (1) Use only the criteria of Table 1A to Appendix A of this subpart 
in assessing the definition;
    (2) For Subpart G, the reporting threshold applies for oxides of 
nitrogen (NOX);
    (3) For Subparts X, AA, and CC, the reporting thresholds apply for 
NOX, carbon monoxide (CO), and volatile organic compounds 
(VOC); and
    (4) For Subpart Z, the reporting thresholds apply for Nox, CO, VOC, 
sulfur dioxide (SO2), ammonia (NH3), total 
particulate matter whose aerodynamic diameter is 2.5 microns or less 
(PM2.5), and total particulate matter whose aerodynamic 
diameter is 10 microns or less (PM10).
    (c) If EPA finalizes revisions to any HAP reporting thresholds 
presented in Table 1B to Appendix A of this subpart, only those revised 
reporting thresholds published in the Federal Register at least 6 
months before the start of an inventory year apply for that inventory 
year (e.g., revised thresholds finalized by June 30, 2026, would apply 
for the 2026 emissions reports).
    (d) To develop new HAP reporting thresholds for revisions of this 
subpart, the EPA would apply the following formula for changes to UREs: 
Revised reporting threshold = (Initial threshold in Table 1B to 
Appendix A of this subpart x URE in 2022)/Revised URE; and
    (e) To develop new HAP reporting thresholds for revisions of this 
subpart, the EPA would apply the following formula for changes to RfCs: 
Revised reporting threshold = (Initial threshold in Table 1B to 
Appendix A of this subpart x Revised RfC)/RfC in 2022.


Sec.  51.12  What pollutants must be reported for point sources?

    (a) Criteria air pollutants and precursors. For the purposes of 
reporting emissions data for this subpart, criteria pollutants and 
precursors are CO, NOX, VOC, SO2, NH3, 
total PM2.5, total PM10, Pb, and either 
condensable PM (when emitted by the facility), or filterable 
PM2.5. When the facility potential to emit of any such 
pollutant is greater than or equal to the reporting thresholds listed 
in Table 1A to Appendix A of this subpart, all such pollutants must be 
reported.
    (b) Hazardous air pollutants.
    (1) For major point sources, reported HAP must include all HAP as 
listed in section 112(b)(1) of the Clean Air Act, 42 U.S.C. 7412(b)(1), 
and 40 CFR 63.64(a).
    (2) For point sources other than major sources, reported HAP must 
include any pollutant listed in Table 1B to Appendix A of this subpart 
when the annual actual emissions of that pollutant or pollutant group 
is greater than or equal to the HAP reporting threshold (presented in 
Table 1B to Appendix A of this subpart).
    (c) Incidental criteria air pollutants or precursors. If a facility 
meets the point source definition of Sec.  51.50 because of the 
facility HAP emissions but does have PTE or actual emissions of 
criteria pollutants or precursors exceeding the reporting thresholds of 
Table 1A to Appendix A of this subpart, emission reports for that 
facility must include incidental criteria pollutants or precursors as 
listed in the ``Associated CAPs'' columns Tables 1B and 1D to Appendix 
A of this subpart.

Specific Reporting Requirements for State Reporters


Sec.  51.15  What data does my State need to report to EPA?

    State annual and triennial requirements are included in paragraphs 
(a) through (f) of this section, with the first inventory year for each 
requirement included in Sec.  51.20. At a State's option, a State may 
report other emissions data described by paragraphs (g) through (i) of 
this section. Requirements on a State for inventories required by 40 
CFR

[[Page 54204]]

Subparts G, X, Z, AA, and ZZ are included at paragraph (j) of this 
section.
    (a) Point sources.
    (1) A State must report the facility inventory and annual actual 
emissions of all criteria pollutants and precursors as described by 
Sec.  51.12(a).
    (2) If the EPA has approved a HAP reporting application as per 
Sec.  51.1(d)(2) of this subpart, a State must report emissions of HAP 
consistent with Sec.  51.12(b) and (c) of this subpart. A State may 
report one or more HAP voluntarily through the 2025 inventory year and 
may not report HAP without an approved application starting with the 
2026 inventory year.
    (3) Starting with the 2026 inventory year, a State must report the 
facility inventory and daily fuel consumption and associated required 
data elements as described in Sec.  51.40 for small generating units 
when:
    (i) Hourly or daily emissions and activity data from the unit are 
not otherwise reported to the EPA, and
    (ii) The unit was operated to offset electricity demand from the 
electricity grid; and
    (iii) The unit is located at a facility that operates on land.
    (4) For electricity generation to offset electricity demand from 
the electricity grid, a State need not include any units in their 
report when an owner/operator has reported daily or hourly emissions or 
activity data directly to the EPA. The unit is located at a facility 
that operates on land.
    (5) A State may report additional pollutants not required by Sec.  
51.12 of this subpart when supported by the EPA electronic reporting 
approaches (as described by Sec. Sec.  51.5(g) and (h) of this 
subpart).
    (6) A State must report point source data consistent with the 
required data elements described by Sec.  51.40 of this subpart.
    (b) Airports. Airport data includes emissions from aircraft that 
occur lower than 3,000 feet above the ground surface (the typical 
height considered to be part of the take-off or landing cycle) and 
emissions from ground support equipment (GSE). A State must report 
stationary sources and qualifying mobile sources as defined by Sec.  
51.5(b) (other than aircraft and GSE) at airports as part of Sec.  
51.15(a) and report aircraft and GSE data for triennial inventory years 
for all airports within a State's implementation planning authority:
    (1) A State must submit activity data (i.e., landings and 
takeoffs).
    (2) In lieu of submitting aircraft activity data required by Sec.  
51.15(b)(1), a State may instead review EPA-provided data as described 
in Sec.  51.5(k) of this subpart, submit comments on that data, and/or 
notify the agency that the State accepts these data.
    (3) In addition to Sec.  51.15(b)(1) or (2), a State may 
voluntarily submit annual actual emissions of aircraft and GSE for some 
or all airports. If submitting annual actual emissions, a State must:
    (i) Use the latest aircraft emissions model specified by the NEI 
plan (as described by Sec.  51.5(k) of this subpart);
    (ii) Submit all pollutants estimated by the latest aircraft 
emissions model;
    (iii) Submit documentation that describes how the State used the 
aircraft emissions model to estimate annual actual emissions and 
quality assured the data; and
    (iv) Report aircraft data consistent with the required data 
elements described by Sec.  51.40 of this subpart.
    (c) Rail yards. Rail yard data include emissions from yard 
locomotive switchers and can include other emissions sources if 
present. For triennial inventory years for all rail yards within a 
State's implementation planning authority:
    (1) A State must submit activity data and documentation that 
explains how the State collected or created the data.
    (2) In lieu of submitting rail yard activity data and documentation 
required by Sec.  51.15(c)(1), a State may instead review EPA-provided 
data as described in Sec.  51.5(k) of this subpart, submit comments on 
that data, and/or notify the EPA that the State accept these values.
    (3) In addition to Sec.  51.15(c)(1) or (2), a State may 
voluntarily submit annual actual emissions for some or all rail yards. 
If submitting annual actual emissions, a State must:
    (i) Submit all pollutants estimated by the EPA rail yard emissions 
method;
    (ii) Submit documentation that describes how the State estimated 
rail yard annual actual emissions and quality assured the data; and
    (iii) Report rail yard data consistent with the required data 
elements described by Sec.  51.40 of this subpart.
    (d) Nonpoint sources. For triennial inventory years, a State must 
report nonpoint sources, including information for all stationary 
source emissions not reported as point sources. For reporting purposes, 
nonpoint sources include commercial marine vessels and underway 
locomotives.
    (1) For this section, ``tool'' refers to any calculation tool, 
spreadsheet, or other electronic instrument provided by the EPA for the 
purpose of nonpoint source emission calculations.
    (2) A State must complete an online survey in the electronic 
reporting approach described in Sec.  51.5(g) to indicate by source 
classification code (SCC) for which nonpoint sources a State will 
report nonpoint tool input data, accept EPA-provided tool input data, 
and/or report annual actual emissions.
    (3) For nonpoint sources with EPA-provided emissions calculation 
tools (as described by Sec.  51.5(k)), excluding commercial marine 
vessels and locomotives:
    (i) A State must report input data for the nonpoint tools in the 
formats provided by EPA; or
    (ii) In lieu of submitting tool inputs, a State may review and 
accept EPA-provided nonpoint tool input data; and
    (iii) In addition to Sec.  51.15(d)(3)(i) or (ii), a State may 
voluntarily submit annual actual emissions of any pollutants allowed by 
the electronic reporting approach (as described by Sec.  51.5(g)).
    (4) For commercial marine vessels and locomotives, a State must 
either:
    (i) Report annual actual emissions of pollutants described by Sec.  
51.12(a); or
    (ii) Provide comment on EPA-provided annual actual emissions data; 
or
    (iii) Accept EPA-provided emissions data.
    (5) For nonpoint sources without the EPA tools:
    (i) A State must report annual actual emissions of pollutants 
described by Sec.  51.12(a) of this subpart if the nonpoint source is 
not excluded by paragraphs (a) (6) and (8) of this section.
    (ii) A State may report emissions of HAP listed in Table 1B.
    (6) For actual annual emissions reported under Sec.  51.15 (d) (3) 
through (5) of this subpart, a State must submit documentation that 
describes how the State estimated nonpoint annual actual emissions and 
quality assured the data.
    (7) A State should exclude episodic wind-generated emissions from 
sources that are not point sources and exclude biogenic sources of 
emissions from vegetation and soils.
    (8) A State may exclude nonpoint sources when such sources are 
reasonably estimated by the State to represent a de minimus percentage 
of total county and State emissions of a given pollutant.
    (9) The EPA nonpoint tools include input data for the entire area 
within county boundaries and State waters, including any Indian 
country. For paragraphs Sec.  51.15 (d) (3) through (6), a State must 
either:
    (i) Include total activity input (inclusive of Indian country) when 
reporting nonpoint emissions; or
    (ii) For a State that includes counties overlapping Indian country 
for an

[[Page 54205]]

Indian Tribe expected to report emissions as per Sec.  51.1(b), the 
State must avoid double counting by excluding the activity within and 
emissions from Indian country from the county total data reported.
    (10) An Indian tribe that reports nonpoint tool inputs and/or 
emissions to meet the requirements of paragraphs (3) through (7) of 
this section must report that data separately for each county that 
includes Indian country. When an Indian tribe reports nonpoint 
emissions, the EPA encourages the tribe to coordinate with the State(s) 
and to use EPA-provided tools and include documentation with their 
submissions.
    (e) Onroad mobile and nonroad mobile sources. For triennial 
inventory years, a State must report onroad mobile and nonroad mobile 
data and include information for all onroad and nonroad categories 
included in the EPA mobile emissions model, such as the MOVES model.
    (1) A State must provide model inputs to the EPA model. A State 
must include at a minimum:
    (i) A county database checklist;
    (ii) Vehicle miles travelled (by county and road type); and
    (iii) Vehicle population (by county, vehicle type, fuel type and 
age).
    (2) If a State has relevant data for the inventory year, a State 
may optionally provide inputs to the latest EPA-developed mobile 
emissions model for the following:
    (i) Hourly average speed distribution by vehicle type, ideally 
different for weekday and weekend (distance traveled in miles divided 
by the time in hours);
    (ii) Vehicle age distribution;
    (iii) Inspection and maintenance program information; and
    (iv) Documentation that describes how the State created these 
inputs and quality assured the data.
    (3) In lieu of submitting model inputs for onroad and nonroad 
mobile sources, California:
    (i) Must submit emissions values for the same pollutants estimates 
by the EPA model for criteria pollutants and precursors;
    (ii) Must submit documentation that describes the model inputs, use 
of the model and any options selected, post-processing steps, and the 
quality assurance performed to estimate the emissions; and
    (iii) May submit emissions of HAP, greenhouse gases, and other 
pollutants. The EPA urges California to include these other pollutants 
when they are estimated by the EPA onroad and nonroad model.
    (iv) Must submit data consistent with the required data elements 
described by Sec.  51.40 of this subpart.
    (4) In lieu of submitting any data, States other than California 
may review and accept EPA-provided model inputs and emission estimates. 
Such States must use the electronic reporting approach provided by the 
EPA (as described by Sec.  51.5(g) of this subpart).
    (f) Prescribed fires other than agricultural burning or land 
clearance burning. A State must annually report data for any prescribed 
burn other than an agricultural burn or land clearance burn that meets 
the criteria described by Sec.  51.1(c)(6) of this subpart. The EPA 
urges States to coordinate between State environmental agencies and 
forestry agencies, and forestry agencies may submit for the State.
    (1) A State must report data consistent with the required and 
optional data elements described by Sec.  51.40 and Table 3 to Appendix 
A of this subpart and other optional data fields as provided by the EPA 
through reporting format instructions.
    (2) For burns that are a combination of broadcast or understory 
burns and pile burns, a State must submit separate entries for the 
broadcast or understory portion of the burn and for the pile burn.
    (g) Wildfires. A State may report wildfire timing and activity data 
using the data elements described by Sec.  51.40 of this subpart. A 
State may review and submit comments about EPA-provided emissions and 
activity data. The EPA urges States to coordinate between State 
environmental agencies and forestry agencies, and forestry agencies may 
submit for the State.
    (h) Agricultural Fires. A State may report agricultural fire timing 
and activity data using the data elements described by Sec.  51.40(f) 
of this subpart. A State may review and submit comments about EPA-
provided emissions and activity data.
    (i) A State may submit sub-annual data to EPA.
    (1) A State may choose to report NOX and VOC summer day 
emissions as required by the ozone SIP requirements rules (40 CFR 
Subparts, X, AA, or CC) or report CO winter work weekday emissions for 
CO nonattainment areas or CO attainment areas with maintenance plans to 
the EIS using the data elements described in this subpart.
    (2) A State may choose to report ozone season day emissions of 
NOX as required under the NOX SIP Call and summer 
day emissions of NOX that may be required under the 
NOX SIP Call (40 CFR 51.122) for controlled sources to the 
EIS using the data elements described in this subpart.
    (3) A State may choose to report average day emissions of any 
pollutants submitted under the PM2.5 SIP Requirements Rule 
(40 CFR Subpart Z) to the EIS using the data elements described in this 
subpart.
    (j) Inventory requirements for State Implementation Plans required 
under Part 51 Subparts G, X, Z, AA, and CC. The following paragraphs 
provide specifications that define how a State shall be consistent with 
the data elements required as per 40 CFR 51.122(g), Sec. Sec.  51.915, 
51.1008 (a)(1)(vi), 51.1115(e), and 51.1315(e).
    (1) Point sources, aircraft and GSE, and railyards. A State must:
    (i) Report sources as point sources as defined by Sec.  51.50 of 
this subpart;
    (ii) Meet the requirements of Sec.  51.15(a)(1), limiting reports 
to those pollutants required by the SIP; and
    (iii) Compile point source data consistent with the required data 
elements described by Sec.  51.40 of this subpart.
    (2) Nonpoint sources. A State must:
    (i) Compile emissions for pollutants required for the SIP using the 
required data elements as described by Sec.  51.40 of this subpart;
    (ii) Include any airports (including aircraft and GSE) not reported 
as a point source; commercial marine vessels, locomotives, agricultural 
burning, prescribed burning, and wildfires;
    (iii) Include all sources of emissions (including biogenic and 
geogenic sources) allowing for the provision of Sec.  51.15(d)(8) of 
this subpart; and
    (iv) Meet the requirements related to adjacent State land and 
Indian country of Sec.  51.15(d) paragraphs (9) and (10) of this 
subpart when Indian country is within a nonattainment area.
    (3) Onroad and nonroad. A State must:
    (i) Compile emissions for pollutants required for the SIP rather 
than model input data using the required data elements as described in 
Sec.  51.40 of this subpart; and
    (ii) Meet the requirements related to adjacent State land and 
Indian country described by Sec.  51.15(d) paragraphs (9) and (10) of 
this subpart when Indian country is within a nonattainment area. While 
Sec.  51.15(d) paragraphs (9) and (10) are for nonpoint sources for the 
triennial reporting requirement under this subpart, they apply to 
onroad and nonroad sources for the purposes of this paragraph.
    (k) Supporting information. A State must report the data elements 
in Tables 2A and 2B to Appendix A of this subpart and other data 
required for use

[[Page 54206]]

of EPA's electronic reporting approach (as described by Sec.  51.5(g)). 
The EPA may ask States to report other data or documentation as needed 
to meet special purposes.
    (l) Quality assurance and supporting information. In addition to 
the required reporting and documentation described in paragraphs (a) 
through (k) of this section, the EPA may ask States to review or revise 
data concerns identified through EPA quality assurance. The EPA may ask 
States for other data or documentation to support a State submission 
when the information provided does not fully explain the source or 
quality of the data. Based on the EPA quality review, the EPA may elect 
not to use the state-provided data if it does not pass quality 
assurance checks or if the State's documentation does not adequately 
explain the origin and quality of the submitted data.


Sec.  51.20  When does my State report which information to EPA?

    A State is required to report both annual and triennial emission 
inventories to the EPA. The content of these inventories may vary 
depending on the inventory year and choices made by a State in 
accordance with the provisions of Sec.  51.1(d).
    (a) Annual inventory.
    (1) For the 2023 through 2026 inventory years, a State must report 
data for point sources to the EPA (as defined by Sec.  51.15(a) of this 
subpart) within 12 months and 15 days of the end of the inventory year 
(e.g., for the 2022 inventory year, by January 15, 2024). For 2023 
through 2025, this requirement excludes reporting of data for small 
generating units consistent with the requirements of Sec.  51.15(a)(3) 
of this subpart.
    (2) Starting with the 2026 inventory year, a State is required to 
report prescribed fire data (except for agricultural burning and land 
clearance burning, as described by Sec.  51.15 (f)) within 6 months 
after the end of the inventory year. For example, 2026 data will be due 
by July 1, 2027, and then every July 1 thereafter. Prior to the 2026 
inventory year, a State may report prescribed burning data or review 
EPA-provided data within 6 months after the end of the inventory year.
    (3) A State may report wildfire and agricultural burning data or 
review EPA-provided data as identified in Sec.  51.15 (g) and (h) by 
the same deadline of Sec.  51.20(a)(2).
    (4) For the 2027 through 2029 inventory years, a State must report 
point source data to the EPA (as described by Sec.  51.15(a) of this 
subpart) within 9 months after the end of the inventory year (e.g., for 
the 2027 inventory year, by September 30, 2028).
    (5) Starting with the 2030 inventory year and for every inventory 
year thereafter, a State must report point source data to the EPA (as 
described by Sec.  51.15(a) of this subpart) within 5 months after the 
end of the inventory year (e.g., for the 2030 inventory year, by May 
31, 2031).
    (b) Triennial inventory. In addition to the annual inventory 
requirements of Sec.  51.20(a) of this subpart, a State must report 
additional data starting with the 2023 inventory year and every 
triennial year thereafter (2026, 2029, etc.) by the dates provided 
below.
    (1) A State must report airport data (as described by Sec.  51.15 
(b) of this subpart) within 9 months after the inventory year, or 60 
calendar days after the EPA provides airport data to a State, whichever 
is later (i.e., for the 2023 inventory year, by September 30, 2024, or 
later).
    (2) A State must report data within 12 months and 15 days after the 
end of the inventory year (i.e., for the 2023 inventory year, by 
January 15, 2025) for:
    (i) Rail yard sources (as described by Sec.  51.15 (c) of this 
subpart);
    (ii) Onroad and nonroad sources (as described by Sec.  51.15 (e) of 
this subpart); and
    (iii) Nonpoint emissions for sources without EPA tools (as 
described by Sec.  51.15(d)(5) of this subpart).
    (3) A State must submit an online nonpoint survey (as described by 
Sec.  51.15(d)(2) of this subpart) within 15 months after the end of 
the inventory year (i.e., for the 2023 inventory year, by March 31, 
2025).
    (4) A State must submit nonpoint tool inputs (as described by Sec.  
51.15(d)(3) of this subpart), within 30 days of the EPA providing tool 
inputs to the State, or within the period defined by the EPA at the 
time the tool inputs are provided, whichever is longer.
    (5) When a State optionally provides nonpoint emissions for 
nonpoint sources with EPA tools (as described by Sec.  51.15(d)(3)(iii) 
of this subpart), a State must report such data and documentation (as 
described by Sec.  51.15(d)(6) of this subpart) within 60 days of the 
EPA providing tool inputs to the State, or within the period defined by 
the EPA at the time the tool inputs are provided, whichever is longer.

Specific Reporting Requirements for Owners and Operators of Facilities


Sec.  51.25  What data do owners or operators of facilities within 
States need to report to EPA?

    (a) An owner/operator of a facility within a State must report the 
facility inventory and annual actual emissions of HAP consistent with 
Sec.  51.5 provisions of this subpart for owners/operators, Sec.  
51.12(b) and (c) of this subpart, and associated required data elements 
(as described by Sec.  51.40 of this subpart) if:
    (1) The facility is in a State that does not have an approved 
application (as per Sec.  51.1(d)(1) of this subpart); and
    (2) The facility is a point source as defined by Sec.  51.50 of 
this subpart.
    (b) An owner/operator of a point source must report results of 
source tests and performance evaluations if:
    (1) Such results are not otherwise reported to the EPA based on 
regulations listed at https://epa.gov/electronic-reporting-air-emissions/cedri#list;
    (2) Such results are gathered to meet any other Federal or State 
requirement;
    (3) Such results are supported by an EPA electronic reporting 
system at the time the test conducted as described in Sec.  51.35 of 
this subpart; and
    (4) The tests are not subject to confidential treatment in 
accordance with exceptions for emission data provided by 40 CFR 2.301 
paragraphs (a)(2)(ii)(A) and (a)(2)(ii)(B).
    (c) Quality assurance and supporting information. The EPA may 
require an owner/operator of a point source to review and/or revise 
data that do not meet quality assurance criteria. The EPA may require 
an owner/operator of a point source to provide other data or 
documentation to support their submissions when information provided 
does not fully explain the source or quality of the data provided.


Sec.  51.27  What data do owners or operators of other facilities need 
to report to EPA?

    (a) An owner/operator of a point source outside the geographic 
scope of a States' implementation planning authority is subject to the 
requirements of Sec.  51.25(b) and (c) of this subpart.
    (b) An owner/operator of a point source outside the geographic 
scope of a States' implementation planning authority must:
    (1) Report the facility inventory and annual actual emissions of 
criteria pollutants, precursors, and HAP consistent with Sec.  51.5 
provisions for owners/operators, Sec.  51.12(a) through (c) of this 
subpart and associated required data elements as described in Sec.  
51.40 of this subpart;

[[Page 54207]]

    (2) Report the facility inventory and daily fuel consumption and 
associated required data elements as described in Sec.  51.40 for small 
generating units when:
    (i) Hourly or daily emissions and activity data from the unit are 
not otherwise reported to the EPA;
    (ii) The unit was operated to offset electricity demand from the 
electricity grid; and
    (iii) The unit is located at a facility that operates on land.
    (3) For portable facilities operating across State and/or Indian 
country boundaries, report the facility inventory and the portion of 
annual emissions not reported by those States and/or tribes.
    (c) For owners/operators of offshore facilities subject to Title V 
emissions reporting and/or emissions quantification requirements, 
owners/operators should use approaches consistent with those permits to 
identify the emissions sources of such facilities and to estimate and 
submit emissions data.
    (d) An owner/operator of a facility subject to the requirements of 
40 CFR 49.138 that also meets the point source definition of this 
subpart is still required to report in accordance with this subpart 
except that such facilities:
    (1) Are exempt from the requirements of this subpart to report 
emissions of those pollutants which are reported under 40 CFR 49.138, 
and
    (2) May at the option of the owner/operator, report those exempt 
pollutants to the EPA electronic reporting system described in Sec.  
51.5(h) of this subpart.


Sec.  51.30  When do owners or operators of facilities need to report 
data to EPA?

    (a) Optional reporting for 2024 and 2025. For the 2024 and 2025 
emissions inventory years, an owner/operator of a point source has the 
option to complete submission of data in accordance with Sec. Sec.  
51.25(a) and 51.27(b) through (d) of this subpart within 6 months after 
the end of the inventory year. The first date for meeting this optional 
reporting approach is May 31, 2025, for the 2024 inventory year.
    (b) Mandatory reporting for 2025. For the 2025 emissions inventory 
year, an owner/operator of a point source within Indian country must 
complete submission of data in accordance with Sec. Sec.  51.25(a) and 
51.27(b) through (d) of this subpart by May 31, 2026.
    (c) Mandatory reporting for 2026. For the 2026 emissions inventory 
year, an owner/operator of a point source reporting under this subpart 
directly to the EPA must complete submission of data required by 
Sec. Sec.  51.25(a) and 51.27(b) through (d) of this subpart by May 31, 
2027.
    (d) Mandatory reporting for 2027 and subsequent years. Starting 
with the 2027 emissions inventory year and every year thereafter, an 
owner/operator of a point source reporting under this subpart directly 
to the EPA must complete submission of data required by Sec. Sec.  
51.25(a) and 51.27(b) through (d) of this subpart within 3 months after 
the inventory year. The first date for meeting this requirement is 
March 31, 2028, for the 2027 inventory year.
    (e) Owners/operators conducting performance tests and performance 
evaluations that meet the requirements of Sec.  51.25(b) of this 
subpart must report results from all such tests electronically to the 
EPA using approaches required by Sec.  51.35 of this subpart. Test 
results conducted on and after the effective date of the final rule 
must be reported by:
    (1) The earliest scheduled reporting date for any form of reporting 
(electronic or otherwise) as required by the Federal or State action 
motivating the measurements; or
    (2) If no scheduled date exists, within 60 days of completing the 
measurements.


Sec.  51.35  How do owners or operators of a facility report emissions, 
source test, and performance evaluation results?

    For purposes of this section, the terms ERT and CEDRI mean ERT and 
CEDRI or analogous electronic reporting approaches provided by the EPA, 
as per Sec.  51.5(i).
    (a) Performance Tests and Performance Evaluations. Owners or 
operators of facilities must submit performance test and performance 
evaluation data following the procedures specified in paragraphs (a)(1) 
through (3) of this section. Section Sec.  51.5(i) of this subpart 
provides more information on ERT and a list of test methods, 
performance evaluations, and pollutants supported.
    (1) Performance Test Methods that are supported by the ERT as 
listed on the ERT website at the time the test is conducted. Upload the 
ERT project data file or an electronic file consistent with the XML 
schema with the appropriate data to CEDRI as a part 51 submission.
    (2) Performance Evaluations of CEMS measuring relative accuracy 
test audit (RATA) pollutants that are supported by the ERT as listed on 
the ERT website at the time the evaluation is conducted. Submit the 
results of the performance evaluation to the EPA via CEDRI. Submit the 
data in a file format generated using the ERT. Alternatively, submit an 
electronic file consistent with the XML schema listed on the ERT 
website.
    (3) Performance Test Methods or Performance Evaluations that are 
not supported by the ERT as listed on EPA's ERT website at the time of 
the test or evaluation is conducted. The results of the performance 
test method or performance evaluation must be included as an attachment 
(such as a Portable Document Format (PDF) file) in the ERT or an 
alternate electronic file consistent with the XML schema listed on 
EPA's ERT website. Submit the ERT-generated package or alternate file 
to the EPA via CEDRI.
    (b) Performance Test and Performance Evaluation Submission Content. 
In addition to the data required to be submitted in Sec.  51.35(a) of 
this subpart, unless otherwise approved by the Administrator in 
writing, submit the following elements identified in paragraphs (b)(1) 
through (11) of this section. If the elements are not already included 
as part of the performance test method or performance evaluation, put 
these elements in an attachment (such as a PDF file) in the ERT or an 
alternate electronic file consistent with the XML schema listed on 
EPA's ERT website. Submit the ERT-generated package or alternate file 
to the EPA using CEDRI.
    (1) The capacity of the unit being tested.
    (2) The load of the unit, in terms of percent capacity, during the 
testing period.
    (3) The level of activity of the unit during the testing period 
(e.g., input consumption rate, product consumption, heat input, and/or 
output production rate).
    (4) The operating conditions of the unit during the testing period.
    (5) The process data, such as temperatures, flow rates, pressure 
differentials, pertaining to the unit and its control devices during 
the testing period.
    (6) General identification information for the facility including a 
mailing address, the physical address, the owner or operator or 
responsible official (where applicable) and his/her email address, and 
the appropriate Federal Registry System (FRS) number for the facility.
    (7) Purpose of the test or evaluation including the applicable 
regulation requiring the test (if any), the pollutant(s) and other 
parameters being measured, the applicable emission standard (if any), 
any process parameter component, and a brief process description.
    (8) Description of the emission unit undergoing testing or 
evaluation including fuel burned, control devices, and vent 
characteristics; the appropriate source classification code (SCC); the

[[Page 54208]]

permitted maximum process rate (where applicable); and the sampling 
location.
    (9) Description of sampling or evaluation and analysis procedures 
used and any modifications to standard procedures, quality assurance 
procedures and results, record of process operating conditions that 
demonstrate the applicable test or evaluation conditions are met, and 
values for any operating parameters for which limits were being set 
during the test or evaluation, as applicable.
    (10) Where a performance test method or performance evaluation 
requires you to record or report, the following shall be included in 
your submission: Record of preparation of standards, record of 
calibrations, raw data sheets for field sampling, raw data sheets for 
field and laboratory analyses, chain-of-custody documentation, and 
example calculations for reported results.
    (11) Identification of the company conducting the performance test 
or evaluation including the company's primary office address, telephone 
number, email address, and the name of the company employee who 
conducted the test.
    (c) Extensions for CDX/CEDRI Outages. If you are required to 
electronically submit a report through CEDRI in the CDX, you may assert 
a claim of an EPA system outage for failure to timely comply with that 
reporting requirement. To assert a claim of an EPA system outage, you 
must meet the requirements outlined in paragraphs (c)(1) through (5) of 
this section. The decision to accept the claim of an EPA system outage 
and allow an extension to the reporting deadline is solely within the 
discretion of the Administrator.
    (1) You must have been or will be precluded from accessing CEDRI 
and submitting a required report within the time prescribed due to an 
outage of either the CEDRI or CDX systems.
    (2) The outage must have occurred within the period beginning five 
business days prior to the date that the submission is due. The outage 
may be planned or unplanned.
    (3) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (4) You must provide to the Administrator a written description 
identifying:
    (i) The date(s) and time(s) when CDX or CEDRI was accessed, and the 
system was unavailable;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to an EPA system outage;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (5) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (d) Extensions for Force Majeure Events. If you are required to 
electronically submit a report through CEDRI, you may assert a claim of 
force majeure for failure to timely comply with that reporting 
requirement. To assert a claim of force majeure, you must meet the 
requirements outlined in paragraphs (d)(1) through (4) of this section.
    (1) You may submit a claim if a force majeure event is about to 
occur, occurs, or has occurred or there are lingering effects from such 
an event within the period beginning five business days prior to the 
date the submission is due. For the purposes of this section, a force 
majeure event is defined as an event that will be or has been caused by 
circumstances beyond the control of the affected facility, its 
contractors, or any entity controlled by the affected facility that 
prevents you from complying with the requirement to submit a report 
electronically by the due date. Examples of such events are acts of 
nature (e.g., hurricanes, earthquakes, or floods), acts of war or 
terrorism, or equipment failure or safety hazard beyond the control of 
the affected facility (e.g., large scale power outage).
    (2) You must submit notification to the Administrator in writing as 
soon as possible following the date you first knew, or through due 
diligence should have known, that the event may cause or has caused a 
delay in reporting.
    (3) You must provide to the Administrator:
    (i) A written description of the force majeure event;
    (ii) A rationale for attributing the delay in reporting beyond the 
regulatory deadline to the force majeure event;
    (iii) A description of measures taken or to be taken to minimize 
the delay in reporting; and
    (iv) The date by which you propose to report, or if you have 
already met the reporting requirement at the time of the notification, 
the date you reported.
    (4) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
    (5) The decision to accept the claim of force majeure and allow an 
extension to the reporting deadline is solely within the discretion of 
the Administrator.
    (e) Recordkeeping. Any records required to be maintained by this 
subpart that are submitted electronically via EPA's CEDRI may be 
maintained in electronic format. This ability to maintain electronic 
copies does not affect the requirement for facilities to make records, 
data, and reports available upon request to a State or the EPA as part 
of an on-site compliance evaluation. For a minimum of 5 years after a 
performance test or performance evaluation is conducted, an owner/
operator must retain and make available upon request, for inspection by 
the Administrator, the records or results of such performance test or 
performance evaluation and other data needed to determine emissions 
from a source.

Additional Specifications for Emission Reports


Sec.  51.40  In what form and format should emissions data be reported 
to EPA?

    (a) General. A State or owner/operator reporting annually or 
triennially under this subpart must report the required data elements 
described in this section using the formats required by the EPA 
electronic data collection approaches described in Sec.  51.45 of this 
subpart. A State or owner/operator must use reporting code values for 
certain data elements consistent with Sec.  51.5(j) of this subpart. 
Because electronic reporting technology changes over time, the EPA 
provides the latest reporting format information and reporting codes on 
the EPA websites referenced in Sec.  51.5 of this subpart.
    (b) Point sources.
    (1) A State or owner/operator (unless the facility is eligible for 
and elects to comply with reporting as provided in Sec.  51.40(b)(3)) 
must:
    (i) Report facility inventory data for the data elements listed in 
the ``point'' column in Table 2A to Appendix A of this subpart;
    (ii) Report emissions data for the data elements listed in the 
``point, airports, railyards'' column in Table 2B to Appendix A of this 
subpart;
    (iii) Use the same unit, process, and release point identifiers for 
all pollutants emitted from the same unit, process, and release point 
at the facility; and
    (iv) Report daily activity data for small generating units 
described by Sec. Sec.  51.15(a)(3) and 51.27(b)(2) of this subpart 
using the data elements listed in Table 2C to Appendix A of this 
subpart.
    (2) An owner/operator of a facility (or a State reporting on their 
behalf) is eligible to use the alternative reporting

[[Page 54209]]

approach of Sec.  51.40(b)(3) for a facility when:
    (i) The owner/operator is a small entity (as defined by Sec.  51.50 
of this subpart);
    (ii) The owner/operator of the facility has never been notified 
that the EPA has modeled a cancer risk for that facility of 20/million 
or more, or the EPA has made such a notification less than 180 days 
prior to the next point source emissions reporting deadline as per 
Sec.  51.20 for owners/operators reporting to a State and as per Sec.  
51.30 for owners/operators reporting to EPA; and
    (iii) Estimates of more detailed emissions are not required by a 
State.
    (3) An owner/operator of a facility (or a State reporting on their 
behalf) meeting the conditions of Sec.  51.40(b)(2) may, as an 
alternative to the reporting requirements of Sec.  51.40(b)(1) report 
as follows:
    (i) Report facility inventory data for the data elements required 
as per the ``point (small entity)'' column in Table 2A to Appendix A of 
this subpart; and
    (ii) Report emissions data for the data elements required as per 
the ``point (small entity)'' column in Table 2B to Appendix A of this 
subpart.
    (c) Airports and rail yards. The EPA provides default data tables 
(e.g., a spreadsheet) for a State to use (as described by Sec.  51.5(k) 
of this subpart).
    (1) To meet the requirement of Sec. Sec.  51.15(b)(1) or (2) and 
51.15(c)(1) or (2) of this subpart, a State must use the data tables 
provided by the EPA to submit data in an electronic format.
    (2) For a State that optionally reports emissions and documentation 
for these sources, the State must:
    (i) Report facility inventory data elements using the data elements 
as described by Table 2A to Appendix A of this subpart.
    (ii) Report aircraft and rail yard source emissions using the data 
elements as described by Table 2B to Appendix A of this subpart.
    (d) Nonpoint sources. The EPA provides default data tables (e.g., 
tools or spreadsheet) for a State to use for some nonpoint sources as 
described by Sec.  51.5(k) of this subpart.
    (1) For nonpoint sources with EPA tools/spreadsheets excluding 
commercial marine vessels and locomotives (as described by Sec.  
51.15(d)(3), a State must use (i.e., review and/or edit and submit 
online) the data tables provided.
    (2) For a State that reports nonpoint actual emissions and 
documentation voluntarily or to meet a requirement of Sec.  51.15(d), 
the State must report nonpoint sources using the data elements listed 
in Table 2B in Appendix A of this subpart. Documentation must be 
submitted in one of the formats supported by the electronic reporting 
system described by Sec.  51.5(g).
    (e) Onroad and nonroad sources.
    (1) For a State submitting MOVES inputs, the State must use MOVES 
input formats for the version of MOVES and meet other requirements for 
electronic submission for a given inventory year (as described by Sec.  
51.5(l)).
    (2) When California reports emissions to comply with Sec.  
51.15(e)(3), the State must report data and documentation to comply 
using the data elements listed in Table 2B in Appendix A of this 
subpart. Documentation must be submitted in one of the formats 
supported by the electronic reporting approach (as described by Sec.  
51.5(g)).
    (f) Prescribed burning, wildfires, and agricultural. When reporting 
required and/or optional data for fires, a State must report data using 
the data elements listed in Table 3 in Appendix A of this subpart. The 
same format is used for both the mandatory data (prescribed burning 
except for agricultural burning or land clearance burning) and the 
voluntary data (wildfires and agricultural burning).


Sec.  51.45  How should States and owners/operators report the data 
required by this subpart?

    (a) A State must submit required annual actual emissions and 
related data and documentation to comply with Sec.  51.15 of this 
subpart to the EPA through the EIS or a comparable electronic reporting 
approach provided by the EPA (as described by Sec.  51.5(g) of this 
subpart).
    (b) An owner/operator must submit annual actual emissions and 
related data and documentation to comply with Sec.  51.25(a) or Sec.  
51.27(b) of this subpart to the EPA through CAERS or a comparable 
electronic reporting approach provided by the EPA (as described by 
Sec.  51.5(h) of this subpart).
    (c) An owner/operator must submit source test and performance 
evaluation data and documentation to comply with Sec.  51.25(b) of this 
subpart to the EPA through CEDRI or a comparable electronic reporting 
approach provided by the EPA (as described by Sec.  51.5(i) of this 
subpart).


Sec.  51.50  What definitions apply to this subpart?

    Aircraft engine type means a code defining a unique combination of 
aircraft and engine used as an input parameter for calculating 
emissions from aircraft.
    Activity data means data needed to calculate emissions using an 
emission factor or emissions calculation tool. Activity data varies 
depending on the emissions calculation approach and therefore the 
emissions source. Examples of activity data include fuel consumed for 
combustion emissions, landing and takeoff data for airport emissions, 
acres burned, material used for solvent evaporation emissions, and 
vehicle miles traveled for onroad mobile source emissions.
    Actual emissions means (for the purposes of this subpart) the 
emissions of a pollutant from a source that is required to be reported 
under this rule, determined by accounting for actual emission rates 
associated with normal source operation and actual or representative 
production rates (i.e., capacity utilization and hours of operation). 
Actual emissions include emissions of a pollutant that occur during 
periods of startup, shutdown, and may include malfunctions. Since 
malfunctions are, by nature, unpredictable and given the myriad 
different types of malfunctions that can occur, malfunction emissions 
are difficult to estimate. However, to the extent that malfunctions 
become a regular and predictable event, then such emissions should be 
quantified with regular and predictable emissions and included in 
actual emissions.
    Agency regulation description means the description of the State, 
local, or tribal regulation when reporting a regulation for which no 
code is available for reporting in EIS.
    Agricultural burn means the use of a prescribed fire to burn crop 
residue.
    Annual emissions means actual emissions for a facility, point, or 
process that are measured or calculated to represent a calendar year.
    Air pollutants means criteria pollutants and their precursors, and 
hazardous air pollutants.
    Aircraft engine type code means a code that defines the engine 
aircraft type for reporting airport emissions to EIS.
    Broadcast burn means a prescribed burning event for which the 
biomass is burned in place, as opposed to being collected for a pile 
burn. Broadcast burning can include cuttings from fuels reduction 
treatments and logging slash that are not piled.
    Combined Air Emissions Reporting System (CAERS) means the 
electronic reporting interface developed by the EPA to enable facility 
reporting to multiple EPA and State emissions reporting programs.
    CDX means EPA's central data exchange, a system used for many 
electronic environmental data submissions to the U.S. EPA.

[[Page 54210]]

    CEDRI means Compliance and Emissions Data Reporting Interface, a 
data collection system used by the EPA to collect electronic 
performance test reports, notification reports, and periodic reports.
    CEMS means continuous emissions monitoring system, which is the 
total equipment necessary for the determination of a concentration or 
emission rate emitted from a source.
    Control identifier means a unique code for a facility that 
identifies a control device, process specialization, or operational 
practice used to reduce emissions (e.g., wet scrubber, low 
NOX burner, flaring, process change, ban).
    Control measure code means an EIS code used to specify the type of 
control measure.
    Control measure percent pollutant reduction efficiency means the 
percent reduction achieved for the pollutant when the control measure 
is operating as designed.
    Control percent effectiveness means an estimate of the portion of 
the reporting period's activity for which the control device was 
operating as designed (regardless of whether the control device is due 
to rule or voluntary).
    Control pollutant code means the pollutant code for the pollutant 
associated with a control measure that has emissions changes caused by 
the control measure.
    Control status code means the EIS code that identifies the 
operating status of the facility site (e.g., operating, temporarily 
shut down, permanently shut down).
    Control status year means the first inventory year for which the 
reported control status code applies.
    Emission calculation method means the code describing how the 
emissions for a pollutant were calculated, e.g., by stack test, 
continuous emissions monitor, EPA emission factor, etc.
    Emission factor means the ratio relating emissions of a specific 
pollutant to an activity throughput level.
    Emission operating type means the operational status of an 
emissions unit for the time period for which emissions are being 
reported, i.e., Routine (including Startup/Shutdown), Malfunction.
    Emission process identifier means a unique code for the process 
generating the emissions.
    Emissions year means the calendar year for which the emissions 
estimates are reported.
    ERT means the Electronic Reporting Tool.
    Facility air centroid coordinates means a latitude-longitude using 
the WGS84 or NAD83 datum that maps to or near the centroid of the air 
emissions activities at a facility.
    Facility attributes means the components of a facility including 
facility characteristics (e.g., name, address, latitude/longitude), 
emissions units and their properties (e.g., identification codes, name, 
capacity), emissions release points and their properties (e.g., stack 
identification code, fugitive release identification code, release 
point height, release point latitude/longitude, release point width or 
diameter), emissions processes and their properties (e.g., process 
identification code, source classification code), and emissions 
controls and their properties (e.g., control identification code, 
control method type).
    Facility inventory means the compilation of data about facility 
attributes for all facilities included in the national emissions 
inventory data repository.
    Facility site identifier means the unique code for a plant or 
facility treated as a point source, containing one or more pollutant-
emitting units. The EPA's reporting format allows for State submittals 
to use either the State's data system identifiers or EPA's EIS 
identifiers.
    Facility site name means the name of the facility.
    Facility site status code means the EIS code that identifies the 
operating status of the facility site (e.g., operating, temporarily 
shut down, permanently shut down).
    Facility site status year means the first inventory year for which 
the reported facility site status code applies.
    Facility source category code means the EIS code that indicates the 
Clean Air Act stationary source designation (e.g., major for criteria 
pollutants and precursors, major for HAP, non-major).
    Federal waters means those waters over the ``outer Continental 
Shelf'' as defined in the Outer Continental Shelf Lands Act (43 U.S.C. 
1331(a)).
    Fugitive release midpoint latitude means the measure of the angular 
distance on a meridian north or south of the equator.
    Fugitive release midpoint longitude means the measure of the 
angular distance on a meridian east or west of the prime meridian.
    Incidental criteria air pollutant or precursor means a criteria 
pollutant or precursor emitted from a facility that meets the point 
source reporting definition for emissions of HAP but not for emissions 
of criteria pollutants and precursors.
    Indian country means Indian country as defined by 18 U.S. Code 
1151.
    Land clearance burn means the use of a prescribed fire to burn 
vegetation debris resulting from land clearing projects for property 
development and right of way maintenance.
    Lead (Pb) means elemental Pb or as a chemical compound containing 
Pb, which should be reported as the mass of the Pb atoms only.
    Mobile source means a motor vehicle, nonroad engine or nonroad 
vehicle, where:
    (a) A motor vehicle is any self-propelled vehicle designed for 
transporting persons or property on a street or highway;
    (b) A nonroad engine is an internal combustion engine (including 
the fuel system) that is not used in a motor vehicle or a vehicle used 
solely for competition, or that is not subject to standards under 
sections 111 or 202 of the CAA; and
    (c) A nonroad vehicle is a vehicle that is powered by a nonroad 
engine and that is not a motor vehicle or a vehicle used solely for 
competition.
    NAICS means North American Industry Classification System code. The 
NAICS codes are U.S. Department of Commerce's codes for categorizing 
businesses by products or services and have replaced Standard 
Industrial Classification codes.
    NAICS type means whether the reported NAICS is a primary, 
secondary, tertiary, etc. NAICS code.
    Nitrogen oxides (NOX) means nitrogen oxides (NOX) as 
defined in 40 CFR 60.2 as all oxides of nitrogen except N2O. 
Nitrogen oxides should be reported on an equivalent molecular weight 
basis as nitrogen dioxide (NO2).
    Nonpoint sources collectively represent individual sources that 
have not been inventoried as specific point or mobile sources and are 
compiled as a county total. The individual sources treated collectively 
as nonpoint sources are typically too small, numerous, or difficult to 
inventory using the methods for the other classes of sources.
    Nonpoint survey means the form within the electronic reporting 
approach described in Sec.  51.5(g) that is used by States to specify 
the use of State and/or EPA data for each nonpoint source type.
    Particulate matter (PM) is a criteria air pollutant. For the 
purpose of this subpart, the following definitions apply:
    (a) Filterable PM2.5 or Filterable PM10: Particles that are 
directly emitted by a source as a solid or liquid at stack or release 
conditions and captured on the filter of a stack test train. Filterable 
PM2.5 is particulate matter with an aerodynamic diameter 
equal to or less than 2.5 micrometers. Filterable PM10 is 
particulate matter with an aerodynamic

[[Page 54211]]

diameter equal to or less than 10 micrometers.
    (b) Condensable PM: Material that is vapor phase at stack 
conditions, but which condenses and/or reacts upon cooling and dilution 
in the ambient air to form solid or liquid PM immediately after 
discharge from the stack.
    (c) Primary PM2.5: The sum of filterable PM2.5 and 
condensable PM.
    (d) Primary PM10: The sum of filterable PM10 and 
condensable PM.
    (e) Secondary PM: Particles that form or grow in mass through 
chemical reactions in the ambient air well after dilution and 
condensation have occurred. Secondary PM is usually formed at some 
distance downwind from the source. Secondary PM should not be reported 
in the emission inventory and is not covered by this subpart.
    Percent control approach effectiveness means the percentage of time 
or activity throughput for a nonpoint source that a control approach is 
operating as designed, including the capture and reduction devices. 
This percentage accounts for the fact that controls typically are not 
100 percent effective because of equipment downtime, upsets and 
decreases in control efficiencies.
    Percent control approach penetration means the percentage of a 
nonpoint source category activity that is covered by the reported 
control measures.
    Percent control measures reduction efficiency means the nonpoint 
source net emission reduction efficiency across all emissions control 
measures.
    Percent control reduction efficiency means the point source percent 
reduction achieved for the pollutant when all control measures are 
operating as designed.
    Percent control release point apportionment means the percentage of 
a point source exhaust gas stream captured for routing to a set of 
control devices.
    Physical address means the location address (street address or 
other physical location description), locality name, State, and postal 
zip code of a facility. This is the physical location where the 
emissions occur; not the corporate headquarters or a mailing address.
    Pile burn means a prescribed fire used to ignite hand or machine 
piles of cut vegetation resulting from vegetation or fuel management 
activities.
    Point source means a stationary or portable facility that (1) is a 
major source under 40 CFR part 70 for any pollutant, or (2) has PTE or 
annual actual emissions of pollutants greater than or equal to the 
reporting thresholds in Table 1A to Appendix A of this subpart, or (3) 
has a primary NAICS code listed in Table 1C to Appendix A of this 
subpart and annual actual emissions of pollutants greater than or equal 
to the reporting HAP reporting thresholds (presented in Table 1B to 
Appendix A of this subpart). In assessing whether emissions levels 
exceed reporting thresholds, all provisions of this subpart related to 
emissions estimation approaches apply, including Sec. Sec.  51.5 and 
51.10 of this subpart.
    Pollutant code means a unique code for each reported pollutant 
assigned by the reporting format specified by the EPA for each 
inventory year.
    Portable facility means a facility that does not have a fixed 
location such as an asphalt plant or portable drilling rig, mobile 
offshore drilling units (MODUs), and offshore installation vessels.
    Prescribed burning or prescribed burn means prescribed burning as 
defined by 40 CFR 50.1.
    Primary NAICS means the NAICS code that most accurately describes 
the facility or supplier's primary product/activity/service. The 
primary product/activity/service is the principal source of revenue for 
the facility or supplier.
    Process status code means the EIS code that indicates the current 
operating status of the process (e.g., operating, temporarily shut 
down, or permanently shut down).
    Process status year means the first inventory year for which the 
reported process status applies.
    Regulatory code means a unique code that identifies an air 
regulation that applies to an emission unit or process.
    Regulation start year means the first year the air regulation 
(identified by the regulatory code) reduced emissions from the unit or 
process.
    Regulation end year means the last year the air regulation 
(identified by the regulatory code) reduced emissions from the unit or 
process.
    Release point apportionment control status means Indicator as to 
whether the release point apportionment is controlled or uncontrolled.
    Release point apportionment identifier means the release point 
identifier to which an emission process is emitting when specifying the 
portion of the process emitting to that release point.
    Release point apportionment means the component name used to 
describe the intersection between an emissions process and a release 
point.
    Release point apportionment percent means the average annual 
percent of an emissions process that is vented through a release point.
    Release point apportionment site path means the site path 
identifier to apply the release point apportionment percent.
    Release point identifier means a code that uniquely identifies a 
release point of emissions at a facility.
    Release point exit gas flow rate means the numeric value of the 
flow rate of a stack gas.
    Release point exit gas temperature means the numeric value of the 
temperature of an exit gas stream in degrees Fahrenheit.
    Release point exit gas velocity means the numeric value of the 
velocity of an exit gas stream.
    Release point height means physical height of a stack or fugitive 
release above the surrounding terrain.
    Release point identifier means a unique code for the point where 
emissions from one or more processes release into the atmosphere.
    Release point identifier effective date means the date on which an 
agency began using the given identifier for the release point object.
    Release point identifier end date means the date on which an agency 
stopped using the given identifier for the release point object (if no 
value is given for this element, it is assumed the identifier is still 
active).
    Release point latitude means the location of a release point, the 
measure of the angular distance on a meridian north or south of the 
equator.
    Release point length means the length of the release in the North-
South direction as if the angle is zero degrees.
    Release point longitude means the location of a release point, the 
measure of the angular distance on a meridian east or west of the prime 
meridian.
    Release point stack diameter means the inner physical diameter of a 
stack.
    Release point status code means the EIS code that indicates the 
current operating status of the release point (e.g., operating, 
temporarily shut down, or permanently shut down).
    Release point status year means the first inventory year for which 
the reported release point status applies.
    Release point type code means the code for physical configuration 
of the release point.
    Release point width means width of the release in the East-West 
direction as if the angle is zero degrees.
    Reporting period type means the code describing the time period 
covered by the emissions reported, i.e., Annual, 5-month ozone season, 
summer day, or winter.
    Sequence number means the number that specifies the order of 
control measures and other site paths within a site path.

[[Page 54212]]

    Site path means a collection of control devices at a facility that 
work in conjunction with each other to reduce emissions from a release 
point.
    Site path average percent apportionment means the average percent 
of an emissions flow (during a year) that is vented through a control 
device (or control path) and provides for specification of venting to 
multiple controls and paths operating in parallel.
    Site path identifier means a code unique to a facility that 
identifies a site path.
    Site path name means the common name given for a site path (e.g., 
by an owner/operator to label the path with words).
    Site path percent effectiveness means an estimate of the portion of 
the reporting period's activity for which the overall control system 
was operating as designed (regardless of whether the control devices 
are due to a requirement or are voluntary).
    Site path pollutant code means the pollutant code for the pollutant 
that is controlled by a site path.
    Site path control measure percent reduction means the percent 
reduction achieved for the pollutant when all control measures are 
operating as designed.
    Site path definition means a collection of data elements that 
identifies the relationship between a path and a control (or a group of 
controls, which must include control identifier(s) and/or path 
identifier(s), the sequence of the controls via sequence numbers, and 
the site path average percent apportionment for each control)
    Small entity means an owner/operator that meets the small business 
definition of CAA section 507(c).
    Small entity type means the small business definitions that apply 
to an owner/operator responsible for reporting emissions for a given 
facility.
    Small generating unit means any boiler, turbine, internal 
combustion engine or other unit that combusts fuel on an occasional 
basis to generate electricity for the electricity grid or for on-site 
use by a facility other than for emergency use.
    Source classification code means a code assigned to an emission 
process identifier that describes the equipment, fuel, and/or operation 
characteristics of the process that emits air pollutants.
    State and county FIPS code means the system of unique identifiers 
in the Federal Information Placement System (FIPS) used to identify 
States, counties and parishes for the entire United States, Puerto 
Rico, and Guam.
    Throughput means a measurable factor or parameter that relates 
directly or indirectly to the emissions of an air pollution source 
during the period for which emissions are reported. Depending on the 
type of source category, activity information may refer to the amount 
of fuel combusted, raw material processed, product manufactured, or 
material handled or processed. It may also refer to population, time of 
operation, employment, or number of units. Activity throughput is 
typically the value that is multiplied against an emission factor to 
generate an emissions estimate.
    Understory burn means a prescribed burning event for which the 
biomass is burned in place under a forest canopy, as opposed to being 
collected for a pile burn. Understory burning can include cuttings from 
fuels reduction treatments and logging slash that are not piled
    Unit design capacity means a measure of the size of a point source, 
based on the reported maximum continuous throughput or output capacity 
of the unit.
    Unit identifier means a unique code for the unit that generates 
emissions, typically a physical piece of equipment or a closely related 
set of equipment.
    Unit status code means the EIS code that indicates the current 
operating status of the unit (e.g., operating, temporarily shut down, 
or permanently shut down).
    Unit status year means the first inventory year for which the 
reported unit status applies.
    VOC means volatile organic compounds (as defined by 40 CFR 51.100).
    XML means eXtensible Markup Language, which is a simple, text-based 
format for representing structured information for documents and data.

Appendix A to Subpart A of Part 51--Tables

 Table 1A--to Appendix A of Subpart A--Reporting Thresholds for Criteria Pollutants and Precursors for Treatment
                                                 as Point Source
----------------------------------------------------------------------------------------------------------------
                                                                 Thresholds for the 2023, 2026, and  subsequent
                                          Thresholds \1\ for                     inventory years
              Pollutant                 2021, 2022, 2024, and  -------------------------------------------------
                                         2025 inventory years          Most areas        Nonattainment areas \2\
----------------------------------------------------------------------------------------------------------------
(1) SO2..............................  >=2,500................  >=100..................  >=100.
                                                                                         PM2.5 (Serious) >=70.
(2) VOC..............................  >=250..................  >=100..................  >=100.
                                                                within OTR \3\ >=50....  within OTR \3\ >=50.
                                                                                         O3 (Serious) >=50.
                                                                                         O3 (Severe) >=25.
                                                                                         O3 (Extreme) >=10.
                                                                                         PM2.5 (Serious) >=70.
(3) NOX..............................  >=2,500................  >=100..................  >=100.
                                                                                         O3 (Serious) >=50.
                                                                                         O3 (Severe) >=25.
                                                                                         O3 (Extreme) >=10.
                                                                                         PM2.5 (Serious) >=70.
(4) CO...............................  >=2,500................  >=1,000................  >=1,000.
                                                                                         CO (all areas) >=100.
(5) Pb...............................  .......................  >=0.5 (actual).........  >=0.5 (actual).
(6) Primary PM10.....................  >=250..................  >=100..................  >=100.
                                                                                         PM10 (Serious) >=70.
(7) Primary PM2.5....................  >=250..................  >=100..................  >=100.
                                                                                         PM2.5 (Serious) >=70.
(8) NH3..............................  >=250..................  >=100..................  >=100.

[[Page 54213]]

 
                                                                                         PM2.5 (Serious) >=70.
----------------------------------------------------------------------------------------------------------------
\1\ Reporting thresholds for point source determination shown in tons per year of potential to emit as defined
  in 40 CFR part 70, except for Pb. Reported emissions should be in actual tons emitted for the required period.
\2\ The point source reporting thresholds vary by attainment status for SO2, VOC, NOX, CO, PM10, PM2.5, and NH3.
\3\ OTR = Ozone Transport Region, which means the area established by CAA section 184(a) or any other area
  established by the Administrator pursuant to CAA section 176A for purposes of ozone.

    This table contains the HAP reporting thresholds for non-major 
sources.

     Table 1B to Appendix A of Subpart A--Reporting Thresholds by Pollutant for Hazardous Air Pollutants for
                                            Treatment as Point Source
----------------------------------------------------------------------------------------------------------------
                                                                                               Actual  emissions
                                                                                               initial threshold
            Description                  Associated CAPs \1\           Pollutant code \2\         (short tons/
                                                                                                     year)
----------------------------------------------------------------------------------------------------------------
1,1,2-Trichloroethane.............  VOC.........................  79005......................               0.22
1,1,2,2-Tetrachloroethane.........  VOC.........................  79345......................                 10
1,2,4-Trichlorobenzene............  VOC.........................  120821.....................                 10
1,2-Dibromo-3-Chloropropane.......  VOC.........................  96128......................             0.0015
1,1-Dimethyl Hydrazine............  VOC.........................  57147......................                 10
1,2-Diphenylhydrazine.............  VOC.........................  122667.....................                 10
1,2-Epoxybutane...................  VOC.........................  106887.....................                 10
1,2-Propylenimine.................  VOC.........................  75558......................                 10
1,3-Butadiene.....................  VOC.........................  106990.....................              0.078
1,3-Dichloropropene...............  VOC.........................  542756.....................                1.1
1,3-Propanesultone................  VOC.........................  1120714....................             0.0043
1,4-Dichlorobenzene...............  VOC.........................  106467.....................               0.26
1-Bromopropane....................  VOC.........................  106945.....................                 10
2,2,4-Trimethylpentane............  VOC.........................  540841.....................                 10
2,4-Dinitrophenol.................  VOC.........................  51285......................                 10
2,4,6-Trichlorophenol.............  VOC.........................  88062......................                2.2
2,4-D, salts and esters...........  VOC.........................  See Table 1D...............                 10
2,4-Dinitrotoluene................  VOC.........................  121142.....................                 10
2,4-Toluene Diisocyanate..........  VOC.........................  584849.....................              0.079
2,4,5-Trichlorophenol.............  VOC.........................  95954......................                 10
2-Chloroacetophenone..............  VOC.........................  532274.....................               0.21
2-Nitropropane....................  VOC.........................  79469......................               0.58
3,3'-Dichlorobenzidine............  VOC.........................  91941......................              0.028
3,3'-Dimethoxybenzidine...........  VOC.........................  119904.....................                 10
3,3'-Dimethylbenzidine............  VOC.........................  119937.....................                 10
4,4'-Methylenebis(2-Chloraniline).  VOC.........................  101144.....................             0.0041
4,4'-Methylenedianiline...........  VOC.........................  101779.....................             0.0027
4,4'-Methylenediphenyl              VOC.........................  101688.....................               0.59
 Diisocyanate.
4-Aminobiphenyl...................  VOC.........................  92671......................                 10
4-Dimethylaminoazobenzene.........  VOC.........................  60117......................             0.0020
4-Nitrobiphenyl...................  VOC.........................  92933......................                 10
4-Nitrophenol.....................  VOC.........................  100027.....................                 10
4,6-Dinitro-o-cresol..............  VOC.........................  534521.....................                 10
Acetaldehyde......................  VOC.........................  75070......................               0.49
Acetamide.........................  VOC.........................  60355......................               0.15
Acetonitrile......................  VOC.........................  75058......................                 10
Acetophenone......................  VOC.........................  98862......................                 10
Acrolein..........................  VOC.........................  107028.....................               0.39
Acrylamide........................  VOC.........................  79061......................              0.016
Acrylic Acid......................  VOC.........................  79107......................                1.1
Acrylonitrile.....................  VOC.........................  107131.....................              0.040
Allyl Chloride....................  VOC.........................  107051.....................               0.54
Aniline...........................  VOC.........................  62533......................                1.5
Anisidine.........................  VOC.........................  90040......................                 10
Antimony..........................  PM..........................  7440360....................                 10
Arsenic...........................  PM..........................  7440382....................            2.3E-04
Asbestos..........................  PM..........................  1332214....................                 10
Benzene...........................  VOC.........................  71432......................              0.096
Benzidine.........................  VOC.........................  92875......................            1.5E-04

[[Page 54214]]

 
Benzotrichloride..................  VOC.........................  98077......................                 10
Benzyl Chloride...................  VOC.........................  100447.....................              0.080
Beryllium.........................  PM..........................  7440417....................            4.1E-04
Biphenyl..........................  VOC.........................  92524......................                 10
Bis(2-Ethylhexyl)Phthalate........  VOC.........................  117817.....................                2.0
Bis(Chloromethyl)Ether............  VOC.........................  542881.....................            3.8E-04
Bromoform.........................  VOC.........................  75252......................                3.8
Cadmium...........................  PM..........................  7440439....................            5.6E-04
Captan............................  VOC.........................  133062.....................                 10
Carbaryl..........................  VOC.........................  63252......................                 10
Carbon Disulfide..................  VOC.........................  75150......................                 10
Carbon Tetrachloride..............  VOC.........................  56235......................               0.45
Carbonyl Sulfide..................  VOC.........................  463581.....................                 10
Catechol..........................  VOC.........................  120809.....................                 10
Chlordane.........................  VOC.........................  57749......................              0.027
Chlorine..........................  ............................  7782505....................               0.26
Chloroacetic Acid.................  VOC.........................  79118......................                 10
Chlorobenzene.....................  VOC.........................  108907.....................                 10
Chlorobenzilate...................  VOC.........................  510156.....................               0.22
Chloroform........................  VOC.........................  67663......................                 10
Chloromethyl Methyl Ether.........  VOC.........................  107302.....................                 10
Chloroprene.......................  VOC.........................  126998.....................             0.0065
Chromium Compounds:
    Chromium......................  PM..........................  7440473....................            1.2E-04
    Chromium (III)................  PM..........................  16065831...................                 10
    Chromic Acid (VI) \3\.........  PM..........................  7738945....................            1.2E-04
    Chromium Trioxide \3\.........  PM..........................  1333820....................            1.2E-04
    Chromium (VI).................  PM..........................  18540299...................            1.2E-04
Cobalt............................  PM..........................  7440484....................            2.2E-04
Coke Oven Emissions...............  VOC.........................  140........................             0.0068
Cresol/Cresylic Acid (Mixed         VOC.........................  See Table 1D...............                 10
 Isomers).
Cumene............................  VOC.........................  98828......................                 10
Cyanide Compounds.................  PM..........................  See Table 1D...............                 10
DDE (1,1-Dichloro-2,2-Bis(p-        VOC.........................  72559......................                 10
 Chlorophenyl) Ethylene).
DDE (2,2-Bis(p-                     VOC.........................  3547044....................                 10
 chlorophenyl)ethane).
Dibenzofuran......................  VOC.........................  132649.....................                 10
Dibutyl Phthalate.................  VOC.........................  84742......................                 10
Dichloroethyl Ether...............  VOC.........................  111444.....................              0.012
Dichlorvos........................  VOC.........................  62737......................                 10
Diethanolamine....................  VOC.........................  111422.....................                 10
Diethyl Sulfate...................  VOC.........................  64675......................                 10
Dimethyl formamide................  VOC.........................  68122......................                 10
Dimethyl Phthalate................  VOC.........................  131113.....................                 10
Dimethyl Sulfate..................  VOC.........................  77781......................                 10
Dimethylcarbamoyl Chloride........  VOC.........................  79447......................                 10
Dioxins and Furans................  PM..........................  See Table 1D...............            1.1E-07
Epichlorohydrin...................  VOC.........................  106898.....................                1.3
Ethyl acrylate....................  VOC.........................  140885.....................                 10
Ethyl Carbamate...................  VOC.........................  51796......................             0.0058
Ethyl Chloride....................  VOC.........................  75003......................                 10
Ethyl Benzene.....................  VOC.........................  100414.....................                 10
Ethylene Dibromide................  VOC.........................  106934.....................             0.0038
Ethylene Dichloride...............  VOC.........................  107062.....................              0.092
Ethylene Glycol...................  VOC.........................  107211.....................                 10
Ethylene Oxide....................  VOC.........................  75218......................            4.1E-04
Ethylene Thiourea.................  VOC.........................  96457......................              0.079
Ethyleneimine (Aziridine).........  VOC.........................  151564.....................                 10
Ethylidene Dichloride.............  VOC.........................  75343......................                2.6
Fine Mineral Fibers...............  PM..........................  See Table 1D...............                 10
Formaldehyde......................  VOC.........................  50000......................              0.083
Glycol Ethers.....................  VOC.........................  See Table 1D...............                 10
Heptachlor........................  VOC.........................  76448......................             0.0021
Hexachlorobenzene.................  VOC.........................  118741.....................              0.010
Hexachlorobutadiene...............  VOC.........................  87683......................               0.14
Hexachlorocyclopentadiene.........  VOC.........................  77474......................               0.31
Hexachloroethane..................  VOC.........................  67721......................                 10
Hexamethylene Diisocyanate........  VOC.........................  822060.....................              0.010
Hexamethylphosphoramide...........  VOC.........................  680319.....................                 10

[[Page 54215]]

 
Hexane............................  VOC.........................  110543.....................                 10
Hydrazine.........................  ............................  302012.....................            3.8E-04
Hydrochloric Acid.................  ............................  7647010....................                 10
Hydrogen Fluoride.................  ............................  7664393....................                7.8
Hydroquinone......................  VOC.........................  123319.....................                 10
Isophorone........................  VOC.........................  78591......................                 10
Lead..............................  PM..........................  7439921....................              0.074
Lindane (all isomers).............  VOC.........................  See Table 1D...............             0.0015
Maleic Anhydride..................  VOC.........................  108316.....................               0.64
Manganese.........................  PM..........................  7439965....................               0.16
Mercury Compounds.................  PM..........................  See Table 1D...............             0.0026
Methanol..........................  VOC.........................  67561......................                 10
Methyl Bromide....................  VOC.........................  74839......................                 10
Methyl Chloride...................  VOC.........................  74873......................                 10
Methyl Chloroform.................  ............................  71556......................                 10
Methyl Iodide.....................  VOC.........................  74884......................                 10
Methyl Isobutyl Ketone............  VOC.........................  108101.....................                 10
Methyl Isocyanate.................  VOC.........................  624839.....................                1.1
Methyl Methacrylate...............  VOC.........................  80626......................                 10
Methyl Tert-Butyl Ether...........  VOC.........................  1634044....................                5.3
Methylene Chloride................  ............................  75092......................                 10
Methylhydrazine...................  VOC.........................  60344......................                 10
Naphthalene.......................  VOC.........................  91203......................              0.027
Nickel Compounds..................  PM..........................  See Table 1D...............             0.0021
Nitrobenzene......................  VOC.........................  98953......................              0.076
N,N-Dimethylaniline...............  VOC.........................  121697.....................                 10
N-Nitrosodimethylamine............  VOC.........................  62759......................            3.5E-04
N-Nitrosomorpholine...............  VOC.........................  59892......................            6.6E-04
o-Toluidine.......................  VOC.........................  95534......................              0.058
p-Dioxane.........................  VOC.........................  123911.....................               0.40
p-Phenylenediamine................  VOC.........................  106503.....................                 10
Parathion.........................  VOC.........................  56382......................                 10
Pentachloronitrobenzene...........  VOC.........................  82688......................                 10
Pentachlorophenol.................  VOC.........................  87865......................                1.7
Phenol............................  VOC.........................  108952.....................                 10
Phosgene..........................  VOC.........................  75445......................               0.48
Phosphine.........................  ............................  7803512....................               0.16
Phosphorus........................  PM..........................  7723140....................                 10
Phthalic Anhydride................  VOC.........................  85449......................                 10
Polychlorinated Biphenyls.........  VOC.........................  See Table 1D...............               0.29
Polycyclic Organic Matter:          VOC.........................  N590.......................              0.027
 Polycyclic aromatic compounds
 (includes 25 specific compounds).
    1,6-Dinitropyrene.............  VOC.........................  42397648...................             0.0011
    1,8-Dinitropyrene.............  VOC.........................  42397659...................             0.0025
    1-Nitropyrene.................  VOC.........................  5522430....................              0.028
    3-Methylcholanthrene..........  VOC.........................  56495......................           4.70E-04
    4-Nitropyrene.................  VOC.........................  57835924...................              0.028
    5-Methylchrysene..............  VOC.........................  3697243....................             0.0025
    6-Nitrochrysene...............  VOC.........................  7496028....................             0.0011
    7,12-Dimethylbenz[a]anthracene  VOC.........................  57976......................           4.90E-05
    7H-Dibenzo[c,g]carbazole......  VOC.........................  194592.....................             0.0025
    Benz[a]anthracene.............  VOC.........................  56553......................              0.028
    Benzo[a]phenanthrene            VOC.........................  218019.....................               0.31
     (Chrysene).
    Benzo[a]pyrene................  VOC.........................  50328......................             0.0025
    Benzo[b]fluoranthene..........  VOC.........................  205992.....................              0.028
    Benzo[j,k]fluorene              VOC.........................  206440.....................              0.027
     (Fluoranthene).
    Benzo[j]fluoranthene..........  VOC.........................  205823.....................              0.028
    Benzo[k]fluoranthene..........  VOC.........................  207089.....................               0.31
    Dibenz[a,h]acridine...........  VOC.........................  226368.....................              0.028
    Dibenz[a,j]acridine...........  VOC.........................  224420.....................              0.028
    Dibenzo[a,e]fluoranthene......  VOC.........................  5385751....................              0.027
    Dibenzo[a,e]pyrene............  VOC.........................  192654.....................             0.0025
    Dibenzo[a,h]anthracene........  VOC.........................  53703......................             0.0025
    Dibenzo[a,h]pyrene............  VOC.........................  189640.....................             0.0011
    Dibenzo[a,i]pyrene............  VOC.........................  189559.....................             0.0011
    Dibenzo[a,l]pyrene............  VOC.........................  191300.....................             0.0011
    Indeno[1,2,3-c,d]pyrene.......  VOC.........................  193395.....................              0.028
Polycyclic Organic Matter, other
 than N590:

[[Page 54216]]

 
    PAH, total \4\................  VOC.........................  130498292..................              0.027
    PAH/POM--Unspecified..........  VOC.........................  250........................              0.027
    Other POM.....................  VOC.........................  See Table 1D...............                 10
    1-Methylnaphthalene...........  VOC.........................  90120......................              0.027
    1-Methylphenanthrene..........  VOC.........................  832699.....................              0.027
    1-Methylpyrene................  VOC.........................  2381217....................              0.027
    12-Methylbenz(a)Anthracene....  VOC.........................  2422799....................              0.027
    2-Chloronaphthalene...........  VOC.........................  91587......................              0.027
    2-Methylnaphthalene...........  VOC.........................  91576......................              0.027
    2-Methylphenanthrene..........  VOC.........................  2531842....................              0.027
    2-Nitrofluorene...............  VOC.........................  607578.....................               0.31
    5-Nitroacenaphthene...........  VOC.........................  602879.....................              0.027
    9-Methyl anthracene...........  VOC.........................  779022.....................              0.027
    Acenaphthene..................  VOC.........................  83329......................              0.027
    Acenaphthylene................  VOC.........................  208968.....................              0.027
    Anthracene....................  VOC.........................  120127.....................              0.027
    Benzo(a)fluoranthene..........  VOC.........................  203338.....................              0.027
    Benzo(c)phenanthrene..........  VOC.........................  195197.....................              0.027
    Benzo(g,h,i)fluoranthene......  VOC.........................  203123.....................              0.027
    Benzo[e]pyrene................  VOC.........................  192972.....................              0.027
    Benzo[g,h,i]perylene..........  VOC.........................  191242.....................              0.027
    Benzofluoranthene.............  VOC.........................  56832736...................              0.027
    BenzoIphenanthrene............  VOC.........................  195197.....................              0.027
    Carbazole.....................  VOC.........................  86748......................               0.31
    Coal Tar......................  VOC.........................  8007452....................             0.0035
    Fluorene......................  VOC.........................  86737......................              0.027
    Indeno[1,2,3-c,d]Pyrene.......  VOC.........................  193395.....................              0.028
    Methylanthracene..............  VOC.........................  26914181...................              0.027
    Methylbenzopyrene.............  VOC.........................  65357699...................              0.027
    Methylchrysene................  VOC.........................  41637905...................             0.0025
    Perylene......................  VOC.........................  198550.....................              0.027
    Phenanthrene..................  VOC.........................  85018......................              0.027
    Pyrene........................  VOC.........................  129000.....................              0.027
Propionaldehyde...................  VOC.........................  123386.....................                5.7
Propoxur..........................  VOC.........................  114261.....................                 10
Propylene Dichloride..............  VOC.........................  78875......................                 10
Propylene Oxide...................  VOC.........................  75569......................                1.3
Quinoline.........................  VOC.........................  91225......................                 10
Quinone...........................  VOC.........................  106514.....................                 10
Selenium..........................  PM..........................  7782492....................                 10
Styrene...........................  VOC.........................  100425.....................                 10
Styrene oxide.....................  VOC.........................  96093......................                 10
Tetrachloroethylene...............  ............................  127184.....................                7.7
Titanium Tetrachloride............  ............................  7550450....................               0.22
Toluene...........................  VOC.........................  108883.....................                 10
Toluene-2,4-Diamine...............  VOC.........................  95807......................              0.010
Toxaphene.........................  VOC.........................  8001352....................             0.0084
Trichloroethylene.................  VOC.........................  79016......................               0.48
Triethylamine.....................  VOC.........................  121448.....................                9.5
Trifluralin.......................  VOC.........................  1582098....................                 10
Vinyl Acetate.....................  VOC.........................  108054.....................                 10
Vinyl Bromide.....................  VOC.........................  593602.....................               0.79
Vinyl Chloride....................  VOC.........................  75014......................               0.43
Vinylidene Chloride...............  VOC.........................  75354......................                 10
Xylenes...........................  VOC.........................  See Table 1D...............                 10
----------------------------------------------------------------------------------------------------------------
\1\ For pollutants denoted with ``PM,'' incidental CAPs include at least primary PM10 and PM2.5 and filterable
  PM10 and PM2.5.
\2\ The pollutant code is usually the Chemical Abstracts Service (CAS) code but is otherwise assigned for use in
  reporting to EPA.
\3\ Report as Chromium (VI), converting mass when emissions value represents compound mass rather than chromium
  mass.
\4\ If total PAH or any combination of individual PAH exceeds the total PAH reporting threshold or any
  individual PAH compound exceeds its reporting threshold, then all individual PAHs as well as total PAH must be
  reported.


[[Page 54217]]


 Table 1C to Appendix A of Subpart A--Applicable Primary NAICS Codes To
          Identify Non-Major Sources for Point Source Reporting
------------------------------------------------------------------------
             NAICS \1\                           Description
------------------------------------------------------------------------
21xxxx, 22xxxx, 3xxxxx except for   Industrial and manufacturing
 311811.                             industries.
4247xx............................  Petroleum and Petroleum Products
                                     Merchant Wholesalers.
481xxx............................  Scheduled Air Transportation.
486xxx............................  Pipeline Transportation.
4883xx............................  Support Activities for Water
                                     Transportation.
493xxx............................  Warehousing and Storage.
5417xx............................  Scientific Research and Development
                                     Services.
54199x............................  Other Professional, Scientific, and
                                     Technical Services.
56191x............................  Packaging and Labeling Services.
5622xx............................  Waste Treatment and Disposal.
5629xx............................  Waste Management and Remediation
                                     Services.
61131x............................  Colleges, Universities, and
                                     Professional Schools.
62211x............................  General Medical and Surgical
                                     Hospitals.
62231x............................  Specialty (except Psychiatric and
                                     Substance Abuse) Hospitals.
811121............................  Automotive Body, Paint and Interior
                                     Repair and Maintenance.\2\
8122xx............................  Death Care Services.
812332............................  Industrial Launderers.
92214x............................  Correctional Institutions.
927xxx............................  Space Research and Technology.
928xxx............................  National Security and International
                                     Affairs.
------------------------------------------------------------------------
\1\ Based on 2017 NAICS codes. The ``x'' values represent all NAICS
  codes starting with the digits preceding the ``x'' values.
\2\ Excluding small entities for primary NAICS 811121.


                 Table 1D--to Appendix A of Subpart A--Pollutants To Report for Compound Groups
----------------------------------------------------------------------------------------------------------------
              Pollutant group                     Component pollutant name       Associated CAPs  Pollutant code
----------------------------------------------------------------------------------------------------------------
2,4-D, salts and esters....................  2,4-Dichlorophenoxy Acetic Acid...              VOC           94757
                                             2,4-D sodium salt.................              VOC         2702729
                                             2,4-D diethanolamine salt.........              VOC         5742198
                                             2,4-D dimethylamine salt..........              VOC         2008391
                                             2,4-D isopropylamine salt.........              VOC         5742176
                                             2,4-D triisopropanolammonium salt.              VOC        32341803
                                             2,4-D butoxyethyl ester...........              VOC         1929733
                                             2,4-D 2-ethylhexyl ester..........              VOC         1928434
                                             2,4-D isopropyl ester.............              VOC           94111
                                             2,4-D butyl ester.................              VOC           94804
                                             2,4-D propylene glycol butyl ether              VOC         1320189
                                              ester (2,4-D 2-butoxymethyl-ethyl
                                              ester).
                                             2,4-D chlorocrotyl ester..........              VOC         2971382
                                             2,4-D 2-ethyl-4-methylpentyl ester              VOC        53404378
Cresol/Cresylic Acid (Mixed Isomers).......  Cresol/Cresylic Acid (Mixed                     VOC         1319773
                                              Isomers).                                      VOC          108394
                                             m-Cresol..........................
                                             o-Cresol..........................              VOC           95487
                                             p-Cresol..........................              VOC          106445
Cyanide Compounds..........................  Calcium Cyanamide.................              PM            57125
                                             Cyanide...........................              PM           156627
                                             Hydrogen Cyanide..................              PM            74908
Dioxins and Furans.........................  1,2,3,4,6,7,8,9-Octachlorodibenzo-              PM          3268879
                                              p-dioxin.
                                             1,2,3,4,6,7,8,9-                                PM         39001020
                                              Octachlorodibenzofuran.
                                             1,2,3,4,6,7,8-Heptachlorodibenzo-p-             PM         35822469
                                              dioxin.
                                             1,2,3,4,6,7,8-                                  PM         67562394
                                              Heptachlorodibenzofuran.
                                             1,2,3,4,7,8,9-                                  PM         55673897
                                              Heptachlorodibenzofuran.
                                             1,2,3,4,7,8-Hexachlorodibenzo-p-                PM         39227286
                                              dioxin.
                                             1,2,3,4,7,8-Hexachlorodibenzofuran              PM         70648269
                                             1,2,3,6,7,8-Hexachlorodibenzo-p-                PM         57653857
                                              dioxin.
                                             1,2,3,6,7,8-Hexachlorodibenzofuran              PM         57117449
                                             1,2,3,7,8,9-Hexachlorodibenzo-p-                PM         19408743
                                              dioxin.
                                             1,2,3,7,8,9-Hexachlorodibenzofuran              PM         72918219
                                             1,2,3,7,8-Pentachlorodibenzo-p-                 PM         40321764
                                              dioxin.
                                             1,2,3,7,8-Pentachlorodibenzofuran.              PM         57117416
                                             2,3,4,6,7,8-Hexachlorodibenzofuran              PM         60851345
                                             2,3,4,7,8-Pentachlorodibenzofuran.              PM         57117314
                                             2,3,7,8-Tetrachlorodibenzo-p-                   PM          1746016
                                              dioxin.
                                             2,3,7,8-Tetrachlorodibenzofuran...              PM         51207319
Fine Mineral Fibers........................  Fine Mineral Fibers...............              PM              383
                                             Ceramic Fibers (man-made fibers)..              PM              608
                                             Glasswool (man-made fibers).......              PM              613

[[Page 54218]]

 
                                             Slagwool (man-made fibers)........              PM              616
                                             Rockwool (man-made fibers)........              PM              617
Glycol Ethers..............................  1,2-Dimethoxyethane...............              VOC          110714
                                             2-(Hexyloxy)Ethanol...............              VOC          112254
                                             2-Butoxyethyl Acetate.............              VOC          112072
                                             2-Propoxyethyl Acetate............              VOC        20706256
                                             Butyl Carbitol Acetate............              VOC          124174
                                             Carbitol Acetate..................              VOC          112152
                                             Cellosolve Acetate................              VOC          111159
                                             Cellosolve Solvent................              VOC          110805
                                             Diethylene Glycol Diethyl Ether...              VOC          112367
                                             Diethylene Glycol Dimethyl Ether..              VOC          111966
                                             Diethylene Glycol Ethyl Methyl                  VOC         1002671
                                              Ether.
                                             Diethylene Glycol-Mono-2-Methyl-                VOC        10143563
                                              Pentyl Ether.
                                             Diethylene Glycol Monobutyl Ether.              VOC          112345
                                             Diethylene Glycol Monoethyl Ether.              VOC          111900
                                             Diethylene Glycol Monoisobutyl                  VOC        18912806
                                              Ether.
                                             Diethylene Glycol Monomethyl Ether              VOC          111773
                                             Ethoxytriglycol...................              VOC          112505
                                             Ethylene Glycol Diethyl Ether.....              VOC          629141
                                             Ethylene Glycol Methyl Ether......              VOC          109864
                                             Ethylene Glycol Mono-2-                         VOC        10137969
                                              Methylpentyl Ether.
                                             Ethylene Glycol Mono-Sec-Butyl                  VOC         7795917
                                              Ether.
                                             Ethylene Glycol Monomethyl Ether                VOC          110496
                                              Acetate.
                                             Ethylene Glycol Monophenyl Ether                VOC        23495127
                                              Propionate.
                                             Glycol Ethers.....................              VOC             171
                                             Isobutyl Cellosolve...............              VOC         4439241
                                             Methoxytriglycol..................              VOC          112356
                                             Methyl Cellosolve Acrylate........              VOC         3121617
                                             N-Hexyl Carbitol..................              VOC          112594
                                             Phenyl Cellosolve.................              VOC          122996
                                             Propyl Cellosolve.................              VOC         2807309
                                             Triethylene Glycol Dimethyl Ether.              VOC          112492
                                             Triglycol Monobutyl Ether.........              VOC          143226
                                             1,2,3,4,5,6-Hexachlorocyclohexane               VOC          608731
                                              (technical) (Mixed Isomers).
                                             .alpha.-Hexachlorocyclohexane.....              VOC          319846
                                             .beta.-Hexachlorocyclohexane......              VOC          319857
                                             .delta.-Hexachlorocyclohexane.....              VOC          319868
                                             .gamma.-Hexachlorocyclohexane                   VOC           58899
                                              (Lindane).
                                             .epsilon.-Hexachlorocyclohexane...              VOC         6108107
                                             .zeta.-Hexachlorocyclohexane......              VOC         6108118
                                             .eta.-Hexachlorocyclohexane.......              VOC         6108129
                                             .theta.-Hexachlorocyclohexane.....              VOC         6108130
                                             1,2,3,4,5,6-Hexachlorocyclohexane               VOC          608731
                                              (technical) (Mixed Isomers).
Mercury Compounds..........................  Mercury...........................  ...............         7439976
                                             Elemental gaseous mercury.........  ...............             200
                                             Gaseous divalent mercury..........  ...............             201
                                             Particulate divalent mercury......              PM              202
Nickel Compounds...........................  Nickel............................              PM          7440020
                                             Nickel Oxide......................              PM          1313991
                                             Nickel Refinery Dust..............              PM              604
                                             Nickel Subsulfide.................              PM         12035722
Other POM..................................  1-Amino-2,4-dibromoanthraquinone..              VOC           81492
                                             1-Amino-2-methylanthraquinone.....              VOC           82280
                                             2-Aminoanthraquinone..............              VOC          117793
                                             2-Phenylphenol....................              VOC           90437
                                             3,3'-Dichlorobenzidine                          VOC          612839
                                              dihydrochloride.
                                             3,3'-Dichlorobenzidine sulfate....              VOC        64969342
                                             3,3'-Dimethoxybenzidine                         VOC        20325400
                                              dihydrochloride.
                                             3,3'-Dimethoxybenzidine                         VOC       111984099
                                              monohydrochloride.
                                             3,3'-Dimethylbenzidine                          VOC          612828
                                              dihydrochloride.
                                             3,3'-Dimethylbenzidine                          VOC        41766750
                                              dihydrofluoride.
                                             4,4'-Diaminodiphenyl ether........              VOC          101804
                                             4,4'-Isopropylidenediphenol.......              VOC           80057
                                             4,4'-Methylenebis(N,N-                          VOC          101611
                                              dimethyl)benzenamine (4,4'-
                                              Methylenebis[N,N-
                                              dimethylaniline]).
                                             4,4'-Thiodianiline................              VOC          139651
                                             4-Aminoazobenzene.................              VOC           60093
                                             Acifluorfen, sodium salt..........              VOC        62476599
                                             alpha-Naphthylamine (1-                         VOC          134327
                                              Naphthalenamine).
                                             Amitraz...........................              VOC        33089611

[[Page 54219]]

 
                                             Benzoyl peroxide..................              VOC           94360
                                             beta-Naphthylamine (2-                          VOC           91598
                                              Naphthalenamine).
                                             Bifenthrin........................              VOC        82657043
                                             C.I. Acid Green 3.................              VOC         4680788
                                             C.I. Acid Red 114.................              VOC         6459945
                                             C.I. Basic Green 4 (Malachite                   VOC          569642
                                              green).
                                             C.I. Basic Red 1..................              VOC          989388
                                             C.I. Direct Black 38..............              VOC         1937377
                                             C.I. Direct Blue 218..............              VOC        28407376
                                             C.I. Direct Blue 6................              VOC         2602462
                                             C.I. Direct Brown 95..............              VOC        16071866
                                             C.I. Disperse Yellow 3............              VOC         2832408
                                             C.I. Food Red 15 (Rhodamine B)....              VOC           81889
                                             C.I. Food Red 5...................              VOC         3761533
                                             C.I. Solvent Orange 7.............              VOC         3118976
                                             C.I. Solvent Yellow 14............              VOC          842079
                                             C.I. Solvent Yellow 3.............              VOC           97563
                                             C.I. Solvent Yellow 34 (Auramine).              VOC          492808
                                             C.I. Vat Yellow 4.................              VOC          128665
                                             Cyfluthrin........................              VOC        68359375
                                             Cyhalothrin.......................              VOC        68085858
                                             Decabromodiphenyl oxide...........              VOC         1163195
                                             Desmedipham.......................              VOC        13684565
                                             Dichlorophene.....................              VOC           97234
                                             Diclofop methyl...................              VOC        51338273
                                             Dicofol...........................              VOC          115322
                                             Diflubenzuron.....................              VOC        35367385
                                             Diphenamid........................              VOC          957517
                                             Diphenylamine.....................              VOC          122394
                                             Fenarimol.........................              VOC        60168889
                                             Fenbutatin oxide..................              VOC        13356086
                                             Fenoxaprop-ethyl..................              VOC        66441234
                                             Fenoxycarb........................              VOC        72490018
                                             Fenpropathrin.....................              VOC        39515418
                                             Fenvalerate.......................              VOC        51630581
                                             Fluvalinate.......................              VOC        69409945
                                             Fomesafen.........................              VOC        72178020
                                             Hexachloronaphthalene.............              VOC         1335871
                                             Hexachlorophene...................              VOC           70304
                                             Hydramethylnon....................              VOC        67485294
                                             Lactofen..........................              VOC        77501634
                                             Michler's ketone..................              VOC           90948
                                             Nitrofen..........................              VOC         1836755
                                             N-Nitrosodiphenylamine............              VOC           86306
                                             Octachloronaphthalene.............              VOC         2234131
                                             Oxyfluorfen.......................              VOC        42874033
                                             Permethrin........................              VOC        52645531
                                             Phenolphthalein (3,3-Bis(4-                     VOC           77098
                                              hydroxyphenyl) phthalide).
                                             Phenothrin........................              VOC        26002802
                                             Phenytoin.........................              VOC           57410
                                             p-Nitrosodiphenylamine............              VOC          156105
                                             Polybrominated biphenyls (PBBs)...              VOC            N575
                                             Quizalofop-ethyl..................              VOC        76578148
                                             Sodium o-phenylphenoxide..........              VOC          132274
                                             Temephos..........................              VOC         3383968
                                             Tetrabromobisphenol A.............              VOC           79947
                                             Triphenyltin chloride.............              VOC          639587
                                             Triphenyltin hydroxide............              VOC           76879
                                             Trypan blue.......................              VOC           72571
                                             Warfarin and salts................              VOC            N874
Polychlorinated Biphenyls..................  2,3,3',4,4',5/2,3,3',4,4',5-                    VOC        38380084
                                              Hexachlorobiphenyl (PCBs156/157).
                                             2,3,3',4,4'-Pentachlorobiphenyl                 VOC        32598144
                                              (PCB-105).
                                             2,3',4,4',5,5'-Hexachlorobiphenyl               VOC        52663726
                                              (PCB-167).
                                             2,3,4,4',5-Pentachlorobiphenyl                  VOC        74472370
                                              (PCB-114).
                                             2,3',4,4',5-Pentachlorobiphenyl                 VOC        31508006
                                              (PCB118).
                                             2,4,4'-Trichlorobiphenyl (PCB-28).              VOC         7012375
                                             2-Chlorobiphenyl (PCB-1)..........              VOC         2051607
                                             3,3',4,4'-Tetrachlorobiphenyl (PCB-             VOC        32598133
                                              77).
                                             4,4'-Dichlorobiphenyl (PCB-15)....              VOC         2050682
                                             Decachlorobiphenyl (PCB-209)......              VOC         2051243
                                             Heptachlorobiphenyl...............              VOC        28655712

[[Page 54220]]

 
                                             Hexachlorobiphenyl................              VOC        26601649
                                             Nonachlorobiphenyl................              VOC        53742077
                                             Octachlorobiphenyl................              VOC        55722264
                                             Pentachlorobiphenyl...............              VOC        25429292
                                             Polychlorinated Biphenyls.........              VOC         1336363
                                             Tetrachlorobiphenyl...............              VOC        26914330
Xylenes....................................  m-Xylene..........................              VOC          108383
                                             o-Xylene..........................              VOC           95476
                                             p-Xylene..........................              VOC          106423
                                             Xylenes (Mixed Isomers)...........              VOC         1330207
----------------------------------------------------------------------------------------------------------------

    All required, conditionally required, and limited optional data 
elements are included in this table. To access a website with the 
reporting formats and all available optional data elements, refer to 
Sec.  51.5(g) and (h) of this subpart.

Table 2A--to Appendix A of Subpart-A--Facility Inventory Data Fields for Reporting Emissions from Point Sources,
                                         Where Required by 40 CFR 51.15
----------------------------------------------------------------------------------------------------------------
                                                  Required (R)\1\, Conditionally Required (C) or Optional (O)
----------------------------------------------------------------------------------------------------------------
                                                                 Point (small
                Data elements                      Point           entity)          Airports        Rail yards
----------------------------------------------------------------------------------------------------------------
State and County FIPS Code or Tribal                       R                R                R                R
 Code.\2\...................................
Facility Site Identifier....................               R                R                R                R
Small Entity Type...........................               O             \3\R   ...............  ...............
Unit Identifier.............................               R                R                R                R
Emission Process Identifier.................               R                O                R                R
Process Status Code and Process Status Code                R                O   ...............  ...............
 Year.......................................
Release Point Identifier....................               R                O                R                R
Facility Site Name..........................               R                R                R                R
Physical Address (Location Address, Locality               R                R                R                R
 Name, State and Postal Code)...............
Facility Source Category Code...............           \3\ R            \3\ R            \3\ R            \3\ R
Facility air centroid coordinates (latitude,               R                R                R                R
 longitude, and datum).\4\..................
Title V operating permit identifier.........            \3\ C            \3\ C            \3\ C            \3\ C
Source Classification Code..................               R                O                R                R
Aircraft Engine Type Code...................  ...............  ...............               R   ...............
Facility Site Status Code and Facility Site                R                R                R                R
 Status Year................................
Release point coordinates (latitude,                   \3\ R                O            \3\ R            \3\ R
 longitude, and datum).\4\..................
Fugitive release midpoint latitude and                      C               O                 C                C
 longitude.\4\..............................
Release Point Height and Unit of Measure....                C               O                 C                C
Release Point Stack Diameter and Unit of                    C               O   ...............  ...............
 Measure....................................
Release Point Exit Gas Temperature..........                C               O   ...............  ...............
Release Point Exit Gas Velocity or Release                  C               O   ...............  ...............
 Point Exit Gas Flow Rate and Unit of
 Measure....................................
Release Point Width, Release Point Length,                  C               O                 C                C
 and Units of Measure.......................
Release Point Status Code and Release Point                R                O                R                R
 Status Year................................
NAICS Code for Facility (5- or 6-digits)....               R                R                R                R
NAICS Type (e.g., ``PRIMARY'',                              C                C                C                C
 ``SECONDARY'', ``TERITIARY'')..............
Unit Design Capacity and Unit of Measure....                C                C               O                 C
Unit Type...................................               R                R                R                R
Unit Status Code and Unit Status Year.......               R                R                R                R
Source Classification Code..................               R                O                R                R
Release Point Apportionment Identifier......               O                O   ...............  ...............
Release Point Apportionment Control Status..                C               O   ...............  ...............
Release Point Apportionment Site Path.......                C               O   ...............  ...............
Release Point Apportionment Percent.........               R                O   ...............  ...............
Release Point Type Code.....................               R                O   ...............  ...............
Regulatory Code, Regulation Start Year, and            \3\ R            \3\ R            \3\ R            \3\ R
 Regulation End Year (as applicable and
 limited to those point sources with State
 or EPA permits)............................
Agency Regulation Description (when                     \3\ C            \3\ C            \3\ C            \3\ C
 providing agency regulations not covered by
 an available regulatory code)..............
Control Identifier..........................            \5\ C               O   ...............  ...............
Control Measure Code........................            \5\ C               O   ...............  ...............
Control Status Code and Control Status Year.            \5\ C  ...............  ...............  ...............
Control Pollutant Code......................            \5\ C               O   ...............  ...............
Control Measure Percent Pollutant Reduction             \5\ C               O   ...............  ...............
 Efficiency.................................
Control Percent Effectiveness...............            \5\ C  ...............  ...............  ...............
Site Path Name..............................            \5\ C               O   ...............  ...............
Site Path Identifier........................            \5\ C               O   ...............  ...............

[[Page 54221]]

 
Site Path Percent Effectiveness.............            \5\ C  ...............  ...............  ...............
Site Path Pollutant Code....................            \5\ C  ...............  ...............  ...............
Site Path Control Measure Percent Reduction.            \5\ C  ...............  ...............  ...............
Site Path Definition (Control Identifier(s)             \5\ C  ...............  ...............  ...............
 and/or Path Identifier(s), Sequence
 Number(s), and Site Path Average Percent
 Apportionment(s))..........................
----------------------------------------------------------------------------------------------------------------
\1\ Facility inventory data elements need only be reported once to the EIS and then revised if needed. They do
  not need to be reported for each triennial or annual emissions inventory.
\2\ Facilities meeting the definition of portable facilities should be reported by State using county code
  ``777''. In this case, facilities are exempt from reporting facility air centroid coordinates and release
  point coordinates.
\3\ Starting with the 2026 inventory year reports.
\4\ Only datum WGS84 and NAD83 are allowed.
\5\ Data are required when a control measure is present.

    All required, conditionally required, and limited optional data 
elements are included in this table. To access a website with the 
reporting formats and all available optional data elements, refer to 
Sec.  51.5(g) and (h) of this subpart.

Table 2B--To Appendix A of Subpart A--Data Fields for Reporting Emissions from Point, Nonpoint, Onroad Mobile and Nonroad Mobile Sources, Where Required
                                                                     by 40 CFR 51.15
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                        Required (R), Conditionally Required (C), Optional (O), or Facility Total (F)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          Point,
                           Data elements                                airports,       Point (small       Nonpoint          Onroad          Nonroad
                                                                        railyards         entity)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emissions Reporting Period.........................................               R                R                R                R                R
Reporting Period Type (e.g., Annual)...............................               R                R                R                R                R
Emission Operating Type (e.g., Routine)............................               R                R   ...............  ...............  ...............
State and County FIPS Code or Tribal Code..........................            \1\ C            \1\ C               R                R                R
Facility Identifier................................................               R                R   ...............  ...............  ...............
Unit Identifier....................................................               R                R   ...............  ...............  ...............
Emission Process Identifier \1\....................................               R                O   ...............  ...............  ...............
Shape Identifiers (for commercial marine vessels)..................  ...............  ...............                C  ...............  ...............
Source Classification Code.........................................  ...............  ...............               R                R                R
Emission Calculation Method........................................               R                R                R   ...............  ...............
Emission Factor (Value, Unit of Measure)...........................               R                O                R   ...............  ...............
Emission Factor Comment............................................            \2\ C               O   ...............  ...............  ...............
Throughput (Value, Material, Unit of Measure, and Type)............               R                O                R                R   ...............
Fuel Use for combustion processes, if not included as throughput                   C               O   ...............  ...............  ...............
 (Value, Unit of Measure)..........................................
Pollutant Code.....................................................               R                R                R                R                R
Annual Emissions and Unit of Measure...............................               R                F                R                R                R
Control Measure Code...............................................                                              \3\ C
Control Pollutant Code.............................................                                              \3\ C
Percent Control Measures Reduction Efficiency......................                                              \3\ C
Percent Control Approach Effectiveness.............................                                              \3\ C
Percent Control Approach Penetration...............................                                              \3\ C
Emissions Documentation Citation...................................  ...............  ...............               R                R                R
Emissions Documentation Attachment.................................  ...............  ...............               R                R                R
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ When using State, local, or tribal identifiers, rather than the unique EIS facility, unit, and emission process identifiers, the State/county FIPs
  code or tribal code must be included with the State, local, or tribal facility identifier, unit identifier and emission process identifiers and all
  codes must match those provided in the Facility Inventory (Table 2A).
\2\ Starting with 2026 inventory year, required when Emissions Calculation Method indicates use of speciation profile and when a source test or
  continuous emissions monitor value is available but not used.
\3\ Data are required when a control measure is present.

    All required data elements are included in this table. To access 
a website with the reporting formats and all available optional data 
elements, refer to Sec.  51.5(g) and (h) of this subpart.

[[Page 54222]]



Table 2C--To Appendix A of Subpart A--Data Fields for Reporting Fuel Use
 for Small Generating Units, Where Required by 40 CFR 51.15(a)(3) and 40
                             CFR 51.27(b)(2)
------------------------------------------------------------------------
                                           Required (R), Conditionally
---------------------------------------   Required (C) or Optional (O)
                                       ---------------------------------
                                             Point,
             Date elements                 airports,       Point (small
                                           railyards         entity)
------------------------------------------------------------------------
Emissions Reporting Period............               R                O
Reporting Period Type (Daily).........               R                O
State and County FIPS Code or Tribal              \1\ C               O
 Code.................................
Facility Site Identifier..............               R                O
Unit Identifier.......................               R                O
Emission Process Identifier...........               R                O
Date of activity......................               R                O
Activity: Fuel Used or Heat Input on                 R                O
 date.................................
Activity unit of measure..............               R                O
Start hour of operation...............               O                O
End hour of operation.................               O                O
------------------------------------------------------------------------
\1\ When using State, local, or tribal identifiers, rather than the
  unique EIS facility, unit, and emission process identifiers, the State/
  county FIPs code or tribal code must be included with the State,
  local, or tribal facility identifier, unit identifier and emission
  process identifiers and all codes must match those provided in the
  Facility Inventory (Table 2A).

    All required and selected optional data elements are included in 
this table. To access a website with the reporting formats and all 
available optional data elements, refer to Sec.  51.5(g) of this 
subpart.

Table 3--To Appendix A of Subpart A--Data Fields for Reporting Data from
              Event Sources, Where Required by 40 CFR 51.15
------------------------------------------------------------------------
                                                          Required (R),
                                                          Conditionally
                     Data elements                       Required (C) or
                                                           Optional (O)
------------------------------------------------------------------------
Emissions Reporting Period.............................               R
Event Identifier.......................................               R
Event Date.............................................               R
State and County FIPS Code or Tribal Code..............               R
Event latitude and longitude centroid for date.........               R
Source classification code.............................               R
Fuel loading per acre and unit of measure..............               O
Fuel moisture and unit of measure (any or all of 1-hr,                O
 10-hr, 100-hr, and 1000-hr values)....................
Emission reduction technique...........................               O
Burn perimeter geographic information system shape.....               O
For broadcast or understory burns:.....................  ...............
    Acres burned actual for date (if total planned                     C
     acres and percent burned not provided)............
    Total planned acres for date (if acres burned not                  C
     provided).........................................
Percent burned for date (if total planned acres                        C (if total
 provided).............................................   planned acres
                                                              provided)
For pile burns:........................................  ...............
    Affected acres.....................................                C
    Number of hand piles per acre......................                C
    Number of machine piles per acre...................                C
    Average height and diameter of hand piles..........               O
Average height and diameter of machine piles...........               O
------------------------------------------------------------------------


[FR Doc. 2023-16158 Filed 8-8-23; 8:45 am]
BILLING CODE 6560-50-P


