[Federal Register Volume 84, Number 89 (Wednesday, May 8, 2019)]
[Proposed Rules]
[Pages 20208-20238]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-09119]



[[Page 20207]]

Vol. 84

Wednesday,

No. 89

May 8, 2019

Part II





Environmental Protection Agency





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40 CFR Part 63





National Emission Standards for Hazardous Air Pollutants: Engine Test 
Cells/Stands Residual Risk and Technology Review; Proposed Rule

  Federal Register / Vol. 84 , No. 89 / Wednesday, May 8, 2019 / 
Proposed Rules  

[[Page 20208]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2018-0753; FRL-9993-20-OAR]
RIN 2060-AT01


National Emission Standards for Hazardous Air Pollutants: Engine 
Test Cells/Stands Residual Risk and Technology Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing the 
results of the residual risk and technology reviews (RTR) for the 
National Emission Standards for Hazardous Air Pollutants (NESHAP) for 
Engine Test Cells/Stands. We found risks due to emissions of air toxics 
from this source category to be acceptable and determined that the 
current NESHAP provides an ample margin of safety to protect public 
health. We identified no new cost-effective controls under the 
technology review to achieve further emission reductions. We are 
proposing no revisions to the numerical emission limit based on the 
risk analysis and technology review. We are proposing to amend 
provisions addressing periods of startup, shutdown, and malfunction 
(SSM), to amend provisions regarding electronic reporting and to make 
clarifying and technical corrections.

DATES: Comments. Comments must be received on or before June 24, 2019. 
Under the Paperwork Reduction Act (PRA), comments on the information 
collection provisions are best assured of consideration if the Office 
of Management and Budget (OMB) receives a copy of your comments on or 
before June 7, 2019.
    Public hearing. If anyone contacts us requesting a public hearing 
on or before May 13, 2019, we will hold a hearing. Additional 
information about the hearing, if requested, will be published in a 
subsequent Federal Register document and posted at https://www.epa.gov/stationary-sources-air-pollution/engine-test-cellsstands-national-emission-standards-hazardous-air. See SUPPLEMENTARY INFORMATION for 
information on requesting and registering for a public hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2018-0753, by any of the following methods:
     Federal eRulemaking Portal: https://www.regulations.gov/ 
(our preferred method). Follow the online instructions for submitting 
comments.
     Email: a-and-r-docket@epa.gov. Include Docket ID No. EPA-
HQ-OAR-2018-0753 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2018-0753.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2018-0753, Mail Code 28221T, 1200 
Pennsylvania Avenue NW, Washington, DC 20460.
     Hand/Courier Delivery: EPA Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Avenue NW, Washington, DC 20004. 
The Docket Center's hours of operation are 8:30 a.m.-4:30 p.m., Monday-
Friday (except Federal holidays).
    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 SUPPLEMENTARY 
INFORMATION section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Jim Eddinger, Sector Policies and Programs Division 
(Mail Code D243-01), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-5426; fax number: (919) 541-4991; 
and email address: eddinger.jim@epa.gov. For specific information 
regarding the risk modeling methodology, contact Ted Palma, Health and 
Environmental Impacts Division (C539-02), Office of Air Quality 
Planning and Standards, U.S. Environmental Protection Agency, Research 
Triangle Park, North Carolina 27711; telephone number: (919) 541-5470; 
fax number: (919) 541-0840; and email address: palma.ted@epa.gov. For 
questions about monitoring and testing requirements, contact Kevin 
McGinn, Sector Policies and Programs Division (Mail Code D243-05), 
Office of Air Quality Planning and Standards, U.S. Environmental 
Protection Agency, Research Triangle Park, North Carolina 27711; 
telephone number: (919) 541-3796; fax number: (919) 541-4991; and email 
address: [email protected] For information about the applicability 
of the national emissions standards for hazardous air pollutants 
(NESHAP) to a particular entity, contact Sara Ayres, Office of 
Enforcement and Compliance Assurance, U.S. Environmental Protection 
Agency, USEPA Region 5 (Mail Code E-19), 77 West Jackson Boulevard, 
Chicago, Illinois 60604; telephone number: (312) 353-6266; and email 
address: ayres.sara@epa.gov.

SUPPLEMENTARY INFORMATION: 
    Public hearing. Please contact Adrian Gates at (919) 541-4860 or by 
email at gates.adrian@epa.gov to request a public hearing, to register 
to speak at the public hearing, or to inquire as to whether a public 
hearing will be held.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2018-0753. All documents in the docket are 
listed in Regulations.gov. Although listed, some information is not 
publicly available, e.g., CBI (Confidential Business Information) 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. 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-
2018-0753. 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 information that you consider to be CBI or 
otherwise protected through https://www.regulations.gov/ or email. This 
type of information should be submitted by mail as discussed below.
    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 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,

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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 or email. Clearly mark the part or 
all of the information that you claim to be CBI. For CBI information on 
any digital storage media that you mail to the EPA, mark the outside of 
the digital storage media as CBI and then 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 Instructions 
above. 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. 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. Send or deliver information identified as CBI only 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-2018-0753.
    Preamble acronyms and abbreviations. We use multiple acronyms and 
terms in this preamble. While this list may not be exhaustive, to ease 
the reading of this preamble and for reference purposes, the EPA 
defines the following terms and acronyms here:

AEGL acute exposure guideline level
AERMOD air dispersion model used by the HEM-3 model
ATSDR Agency for Toxics Substances and Disease Registry
BACT best available control technology
CAA Clean Air Act
CalEPA California EPA
CBI Confidential Business Information
CDX Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CO carbon monoxide
DoD Department of Defense
ECHO Enforcement and Compliance History Online
EPA Environmental Protection Agency
ERPG Emergency Response Planning Guideline
ERT Electronic Reporting Tool
HAP hazardous air pollutant(s)
HCl hydrochloric acid
HEM-3 Human Exposure Model, Version 1.1.0
HF hydrogen fluoride
HI hazard index
hp horsepower
HQ hazard quotient
IRIS Integrated Risk Information System
km kilometer
LAER lowest achievable emissions rate
MACT maximum achievable control technology
MIR maximum individual risk
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NASA National Aeronautics and Space Administration
NEI National Emission Inventory
NESHAP national emission standards for hazardous air pollutants
OAQPS Office of Air Quality Planning and Standards
OMB Office of Management and Budget
PB-HAP hazardous air pollutants known to be persistent and bio-
accumulative in the environment
PM10 particulate matter with particles less than 10 
micrometers in diameter
POM polycyclic organic matter
ppmvd parts per million by volume dry basis
RACT reasonably available control technology
REL reference exposure level
RFA Regulatory Flexibility Act
RfC reference concentration
RfD reference dose
RTR residual risk and technology review
SAB Science Advisory Board
SCC Source Classification Code
SSM startup, shutdown, and malfunction
THC total hydrocarbons
TOSHI target organ-specific hazard index
tpy tons per year
TRIM.FaTE Total Risk Integrated Methodology.Fate, Transport, and 
Ecological Exposure model
UF uncertainty factor
[micro]g/m\3\ microgram per cubic meter
UMRA Unfunded Mandates Reform Act
URE unit risk estimate
VOC volatile organic compounds

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

I. General Information
    A. Does this action apply to me?
    B. Where can I get a copy of this document and other related 
information?
II. Background
    A. What is the statutory authority for this action?
    B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?
    C. What data collection activities were conducted to support 
this action?
    D. What other relevant background information and data are 
available?
III. Analytical Procedures and Decision-Making
    A. How do we consider risk in our decision-making?
    B. How do we perform the technology review?
    C. How do we estimate post-MACT risk posed by the source 
category?
IV. Analytical Results and Proposed Decisions
    A. What are the results of the risk assessment and analyses?
    B. What are our proposed decisions regarding risk acceptability, 
ample margin of safety, and adverse environmental effect?
    C. What are the results and proposed decisions based on our 
technology review?
    D. What other actions are we proposing?
    E. What compliance dates are we proposing?
V. Summary of Cost, Environmental, and Economic Impacts
    A. What are the affected sources?
    B. What are the air quality impacts?
    C. What are the cost impacts?
    D. What are the economic impacts?
    E. What are the benefits?
VI. Request for Comments
VII. Submitting Data Corrections
VIII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulation and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)

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    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    J. National Technology Transfer and Advancement Act (NTTAA)
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. General Information

A. Does this action apply to me?

    Table 1 of this preamble lists the NESHAP and associated regulated 
industrial source category that is the subject of this proposal. Table 
1 is not intended to be exhaustive, but rather provides a guide for 
readers regarding the entities that this proposed action is likely to 
affect. The proposed standards, once promulgated, will be directly 
applicable to the affected sources. Federal, state, local, and tribal 
government entities would not be affected by this proposed action. As 
defined in the Initial List of Categories of Sources Under Section 
112(c)(1) of the Clean Air Act Amendments of 1990 (see 57 FR 31576; 
July 16, 1992) and Documentation for Developing the Initial Source 
Category List, Final Report (see EPA-450/3-91-030, July 1992), the 
``Engine Test Facilities'' source category is any facility engaged in 
the testing of stationary and mobile engines, including turbines and 
reciprocating engines. Test cells/stands used for testing rocket 
engines were identified as an additional subcategory during the NESHAP 
rulemaking.

    Table 1--NESHAP and Industrial Source Categories Affected by This
                             Proposed Action
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        Source category               NESHAP           NAICS code \1\
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Engine Test Facilities........  Engine Test Cells/ 333120, 333618,
                                 Stands.            333111, 334312,
                                                    336111, 336120,
                                                    336112, 336992,
                                                    336312, 336350,
                                                    54171, 541380,
                                                    333611, 336411,
                                                    336412, 336414,
                                                    92711.
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\1\ North American Industry Classification System.

B. Where can I get a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
this action is available on the internet. Following signature by the 
EPA Administrator, the EPA will post a copy of this proposed action at 
https://www.epa.gov/stationary-sources-air-pollution/engine-test-cellsstands-national-emission-standards-hazardous-air. Following 
publication in the Federal Register, the EPA will post the Federal 
Register version of the proposal and key technical documents at this 
same website. Information on the overall RTR program is available at 
https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.
    A redline version of the regulatory language that incorporates the 
proposed changes in this action is available in the docket for this 
action (Docket ID No. EPA-HQ-OAR-2018-0753).

II. Background

    A. What is the statutory authority for this action?
    The statutory authority for this action is provided by sections 112 
and 301 of the Clean Air Act (CAA), as amended (42 U.S.C. 7401 et 
seq.). Section 112 of the CAA establishes a two-stage regulatory 
process to develop standards for emissions of hazardous air pollutants 
(HAP) from stationary sources. Generally, the first stage involves 
establishing technology-based standards and the second stage involves 
evaluating those standards that are based on maximum achievable control 
technology (MACT) to determine whether additional standards are needed 
to address any remaining risk associated with HAP emissions. This 
second stage is commonly referred to as the ``residual risk review.'' 
In addition to the residual risk review, the CAA also requires the EPA 
to review standards set under CAA section 112 every 8 years to 
determine if there are ``developments in practices, processes, or 
control technologies'' that may be appropriate to incorporate into the 
standards. This review is commonly referred to as the ``technology 
review.'' When the two reviews are combined into a single rulemaking, 
it is commonly referred to as the ``risk and technology review.'' The 
discussion that follows identifies the most relevant statutory sections 
and briefly explains the contours of the methodology used to implement 
these statutory requirements. A more comprehensive discussion appears 
in the document titled CAA Section 112 Risk and Technology Reviews: 
Statutory Authority and Methodology, in the docket for this rulemaking.
    In the first stage of the CAA section 112 standard setting process, 
the EPA promulgates technology-based standards under CAA section 112(d) 
for categories of sources identified as emitting one or more of the HAP 
listed in CAA section 112(b). Sources of HAP emissions are either major 
sources or area sources, and CAA section 112 establishes different 
requirements for major source standards and area source standards. 
``Major sources'' are those that emit or have the potential to emit 10 
tons per year (tpy) or more of a single HAP or 25 tpy or more of any 
combination of HAP. All other sources are ``area sources.'' For major 
sources, CAA section 112(d)(2) provides that the technology-based 
NESHAP must reflect the maximum degree of emission reductions of HAP 
achievable (after considering cost, energy requirements, and non-air 
quality health and environmental impacts). These standards are commonly 
referred to as MACT standards. CAA section 112(d)(3) also establishes a 
minimum control level for MACT standards, known as the MACT ``floor.'' 
The EPA must also consider control options that are more stringent than 
the floor. Standards more stringent than the floor are commonly 
referred to as beyond-the-floor standards. In certain instances, as 
provided in CAA section 112(h), the EPA may set work practice standards 
where it is not feasible to prescribe or enforce a numerical emission 
standard. For area sources, CAA section 112(d)(5) gives the EPA 
discretion to set standards based on generally available control 
technologies or management practices (GACT standards) in lieu of MACT 
standards.
    The second stage in standard-setting focuses on identifying and 
addressing any remaining (i.e., ``residual'') risk according to CAA 
section 112(f). For source categories subject to MACT standards, 
section 112(f)(2) of the CAA requires the EPA to determine whether 
promulgation of additional standards is needed to provide an ample 
margin of safety to protect public health or to prevent an adverse 
environmental effect. Section 112(d)(5) of the CAA provides that this 
residual risk review is not required for categories of area sources 
subject to GACT standards. Section 112(f)(2)(B) of the CAA further 
expressly preserves the EPA's use of the

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two-step approach for developing standards to address any residual risk 
and the Agency's interpretation of ``ample margin of safety'' developed 
in the National Emissions Standards for Hazardous Air Pollutants: 
Benzene Emissions from Maleic Anhydride Plants, Ethylbenzene/Styrene 
Plants, Benzene Storage Vessels, Benzene Equipment Leaks, and Coke By-
Product Recovery Plants (Benzene NESHAP) (54 FR 38044, September 14, 
1989). The EPA notified Congress in the Risk Report that the Agency 
intended to use the Benzene NESHAP approach in making CAA section 
112(f) residual risk determinations (EPA-453/R-99-001, p. ES-11). The 
EPA subsequently adopted this approach in its residual risk 
determinations and the United States Court of Appeals for the District 
of Columbia Circuit (the Court) upheld the EPA's interpretation that 
CAA section 112(f)(2) incorporates the approach established in the 
Benzene NESHAP. See NRDC v. EPA, 529 F.3d 1077, 1083 (D.C. Cir. 2008).
    The approach incorporated into the CAA and used by the EPA to 
evaluate residual risk and to develop standards under CAA section 
112(f)(2) is a two-step approach. In the first step, the EPA determines 
whether risks are acceptable. This determination ``considers all health 
information, including risk estimation uncertainty, and includes a 
presumptive limit on maximum individual lifetime [cancer] risk (MIR) 
\1\ of approximately 1 in 10 thousand.'' 54 FR 38045, September 14, 
1989. If risks are unacceptable, the EPA must determine the emissions 
standards necessary to reduce risk to an acceptable level without 
considering costs. In the second step of the approach, the EPA 
considers whether the emissions standards provide an ample margin of 
safety to protect public health ``in consideration of all health 
information, including the number of persons at risk levels higher than 
approximately 1 in 1 million, as well as other relevant factors, 
including costs and economic impacts, technological feasibility, and 
other factors relevant to each particular decision.'' Id. The EPA must 
promulgate emission standards necessary to provide an ample margin of 
safety to protect public health. After conducting the ample margin of 
safety analysis, we consider whether a more stringent standard is 
necessary to prevent, taking into consideration costs, energy, safety, 
and other relevant factors, an adverse environmental effect.
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    \1\ Although defined as ``maximum individual risk,'' MIR refers 
only to cancer risk. MIR, one metric for assessing cancer risk, is 
the estimated risk if an individual were exposed to the maximum 
level of a pollutant for a lifetime.
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    CAA section 112(d)(6) separately requires the EPA to review 
standards promulgated under CAA section 112 and revise them ``as 
necessary (taking into account developments in practices, processes, 
and control technologies)'' no less often than every 8 years. In 
conducting this review, which we call the ``technology review,'' the 
EPA is not required to recalculate the MACT floor. Natural Resources 
Defense Council (NRDC) v. EPA, 529 F.3d 1077, 1084 (D.C. Cir. 2008). 
Association of Battery Recyclers, Inc. v. EPA, 716 F.3d 667 (D.C. Cir. 
2013). The EPA may consider cost in deciding whether to revise the 
standards pursuant to CAA section 112(d)(6).

B. What is this source category and how does the current NESHAP 
regulate its HAP emissions?

    The NESHAP for the Engine Test Cells/Stands source category was 
promulgated on May 27, 2003 (68 FR 28774), and codified at 40 CFR part 
63, subpart PPPPP. As promulgated in 2003, the Engine Test Cells/Stands 
NESHAP applies to engine test cells/stands located at major sources of 
HAP emissions. An engine test cell/stand is any apparatus used for 
testing uninstalled stationary or uninstalled mobile engines. That is, 
the NESHAP regulates the testing of engines, not the testing of any 
final product (e.g., automobile, boat, or power generator). Engine test 
cells/stands are used for research and development activities (e.g., 
new model development, endurance testing) and for quality control at 
engine production facilities. The affected source is defined in the 
NESHAP as the collection of all equipment and activities associated 
with engine test cells/stands used for testing uninstalled engines. The 
NESHAP does not apply to any portion of the affected source used in 
research and teaching activities at facilities that are not engaged in 
the development of engines or engine test services for commercial 
purposes or any portion of the affected source operated to test or 
evaluate fuels, transmissions, or electronics.
    The NESHAP covers four subcategories of engine test cells/stands: 
(1) Cells/stands used for testing internal combustion engines with 
rated power of 25 horsepower (hp) or more; (2) cells/stands used for 
testing internal combustion engines with rated power of less than 25 
hp; (3) cells/stands used for testing combustion turbine engines; and 
(4) cells/stands used for testing rocket engines. The first two 
subcategories cover facilities where reciprocating engines are tested, 
such as automobile engines and emergency generators. The combustion 
turbine subcategory includes jet engines, turboprops, and gas turbines.
    The affected source is further classified as either an existing, 
new, or reconstructed source. An affected source is said to be 
``existing'' if its construction began on or before May 14, 2002, and 
no reconstruction of the source occurred after that date. An affected 
source is considered ``new'' or ``reconstructed'' if it was constructed 
or reconstructed after May 14, 2002. The distinction between 
``existing'' and ``new/reconstructed'' affected sources is important as 
existing affected sources testing engines are not subject to emission 
limits. However, new and reconstructed affected sources testing 
internal combustion engines with a rated power of 25 hp or more are 
subject to emission limits.
    The typical engine test cell consists of one or more stands for 
mounting engines, storage tanks, and piping for fuels and cooling 
fluids, an electronic control system, data acquisition instrumentation 
for monitoring and recording engine parameters during testing, blast 
panels, fire suppression equipment, and spill collection systems. Most 
engine testing is performed indoors in a purpose-built enclosure 
equipped with ventilation systems with hoods, ducts, and fans. However, 
testing of jet engines, turboprops, large turbines, and rocket engines 
is sometimes conducted on outdoor test stands. Some test cells/stands 
include climate control systems that enable testing to be completed 
under a variety of temperature, humidity, and pressure conditions. Test 
cells used for aircraft engines and rockets sometimes include specially 
designed air handling systems that simulate high altitude conditions. 
Most sources have between two and 10 engine test cells/stands. However, 
a few larger sources have over 100 test cells.
    Engine test cells/stands emit HAP in the exhaust gases from 
combustion of gaseous and liquid fuels in the engines tested. The 
emission rates and annual emissions vary based on the size and design 
of the engines tested, the types of fuels burned, and the number, type, 
and duration of tests performed. A wide range of engines are tested in 
the U.S., including two- and four-stroke reciprocating engines used in 
boats, automobiles, buses, and trucks; combustion turbines used for 
power generation; jet and turboprop engines used in military and 
civilian aircraft; and rocket engines used in a variety of military and 
civilian applications. Fuels

[[Page 20212]]

used during testing include biofuels, natural gas, propane, gasoline, 
kerosene, jet fuel, diesel, and various grades of fuel oil.
    The sources of emissions are the exhaust gases from combustion of 
fuels in the engines being tested in the test cells/stands. The primary 
HAP present in the exhaust gases from engine test cells/stands are 
formaldehyde, benzene, acetaldehyde, and 1,3-butadiene.
    The Engine Test Cells/Stands NESHAP provides the owner or operator 
of a new or reconstructed affected source used in whole or in part for 
testing internal combustion engines with rated power of 25 hp or more 
and located at a major source of HAP emissions two compliance options: 
(1) Reduce carbon monoxide (CO) or total hydrocarbons (THC) emissions 
in the exhaust from the new or reconstructed affected source to 20 
parts per million by volume dry basis (ppmvd) or less, at 15-percent 
oxygen (O2) content, or (2) reduce CO or THC emissions in 
the exhaust from the new or reconstructed affected source by 96 percent 
or more. If a new affected source elects to comply with the percent 
reduction emission limitation, the affected source must conduct an 
initial performance test to determine the capture and control 
efficiencies of the equipment and to establish operating limits to be 
achieved on a continuous basis.

C. What data collection activities were conducted to support this 
action?

    During the development of 40 CFR part 63, subpart PPPPP, the EPA 
collected information on the emissions, operations, and location of 
engine test cells/stands. Since this information was collected prior to 
the 2003 promulgation of 40 CFR part 63, subpart PPPPP, the EPA 
prepared a questionnaire in 2016 in order to collect current 
information on the location and number of engine test cells/stands, 
types and quantities of emissions, number and type of engines tested, 
length and purpose of tests, annual operating hours, types and 
quantities of fuels burned, and information on air pollution control 
devices and emission points. Ten companies completed the 2016 
questionnaire for which they reported data for 15 major source 
facilities. The EPA used data from the 2016 questionnaires to develop 
the modeling dataset for the 40 CFR part 63, subpart PPPPP risk 
modeling.
    The list of facilities that are subject to 40 CFR part 63, subpart 
PPPPP was developed using EPA's Enforcement and Compliance History 
Online (ECHO) database, the 2014 National Emissions Inventory (2014 
NEI) and the facility list developed for the 2003 promulgation of 40 
CFR part 63, subpart PPPPP. Facilities with engine test cells/stands 
were identified in the 2014 NEI records by either the source 
classification codes (SCCs) or NAICS codes. The facility list was then 
refined using air permit information to determine whether the facility 
was a major source of HAP and subject to 40 CFR part 63, subpart PPPPP. 
The initial list of facilities and their engine test cells/stands was 
posted to the EPA's Engine Test Cells/Stands: National Emission 
Standards for Hazardous Air Pollutants (NESHAP) website for review by 
industry and trade organizations.\2\ The EPA also emailed the list to 
several trade organizations as part of an outreach effort to the 
industry. EPA Regional offices and state and local air pollution 
control agencies were asked to review the list and provide corrections 
as necessary. The Department of Defense (DoD) and the National 
Aeronautics and Space Administration (NASA) were also consulted and 
provided information for engine testing facilities located at research 
sites and military bases. Changes to the facility list were made based 
on the new information received. The final risk modeling datafile 
included all 59 facilities, each with one or more engine test cells/
stands that are in the source category, not just the engine test cells/
stands facilities that are subject to emission limits.
---------------------------------------------------------------------------

    \2\ See https://www.epa.gov/stationary-sources-air-pollution/engine-test-cellsstands-national-emission-standards-hazardous-air#rule-summary.
---------------------------------------------------------------------------

D. What other relevant background information and data are available?

    In addition to the ECHO and NEI databases, the EPA reviewed the 
additional information sources listed below and consulted with 
stakeholders regulated under the Engine Test Cells/Stands NESHAP to 
determine whether there have been developments in practices, processes, 
or control technologies by engine testing sources. These include the 
following:
     Permit limits and selected compliance options from permits 
submitted by facilities as part of their response to the questionnaire 
and collected from state agencies;
     Information on air pollution control options in the engine 
testing industry from the reasonably available control technology/best 
available control technology/lowest achievable emission rate 
Clearinghouse (RBLC);
     Information on the most effective ways to control 
emissions of volatile organic compounds (VOC) and organic HAP from 
sources in various industries; and
     Communication with trade groups and associations 
representing industries in the affected NAICS categories and their 
members.

III. Analytical Procedures and Decision-Making

    In this section, we describe the analyses performed to support the 
proposed decisions for the RTR and other issues addressed in this 
proposal.

A. How do we consider risk in our decision-making?

    As discussed in section II.A of this preamble and in the Benzene 
NESHAP, in evaluating and developing standards under CAA section 
112(f)(2), we apply a two-step approach to determine whether or not 
risks are acceptable and to determine if the standards provide an ample 
margin of safety to protect public health. As explained in the Benzene 
NESHAP, ``the first step judgment on acceptability cannot be reduced to 
any single factor'' and, thus, ``[t]he Administrator believes that the 
acceptability of risk under section 112 is best judged on the basis of 
a broad set of health risk measures and information.'' 54 FR 38046, 
September 14, 1989. Similarly, with regard to the ample margin of 
safety determination, ``the Agency again considers all of the health 
risk and other health information considered in the first step. Beyond 
that information, additional factors relating to the appropriate level 
of control will also be considered, including cost and economic impacts 
of controls, technological feasibility, uncertainties, and any other 
relevant factors.'' Id.
    The Benzene NESHAP approach provides flexibility regarding factors 
the EPA may consider in making determinations and how the EPA may weigh 
those factors for each source category. The EPA conducts a risk 
assessment that provides estimates of the MIR posed by the HAP 
emissions from each source in the source category, the hazard index 
(HI) for chronic exposures to HAP with the potential to cause noncancer 
health effects, and the hazard quotient (HQ) for acute exposures to HAP 
with the potential to cause noncancer health effects.\3\ The assessment 
also provides estimates of the distribution of cancer risk within the

[[Page 20213]]

exposed populations, cancer incidence, and an evaluation of the 
potential for an adverse environmental effect. The scope of the EPA's 
risk analysis is consistent with the EPA's response to comments on our 
policy under the Benzene NESHAP where the EPA explained that:
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    \3\ The MIR is defined as the cancer risk associated with a 
lifetime of exposure at the highest concentration of HAP where 
people are likely to live. The HQ is the ratio of the potential 
exposure to the HAP to the level at or below which no adverse 
chronic noncancer effects are expected; the HI is the sum of HQs for 
HAP that affect the same target organ or organ system.

[t]he policy chosen by the Administrator permits consideration of 
multiple measures of health risk. Not only can the MIR figure be 
considered, but also incidence, the presence of non-cancer health 
effects, and the uncertainties of the risk estimates. In this way, 
the effect on the most exposed individuals can be reviewed as well 
as the impact on the general public. These factors can then be 
weighed in each individual case. This approach complies with the 
Vinyl Chloride mandate that the Administrator ascertain an 
acceptable level of risk to the public by employing his expertise to 
assess available data. It also complies with the Congressional 
intent behind the CAA, which did not exclude the use of any 
particular measure of public health risk from the EPA's 
consideration with respect to CAA section 112 regulations, and 
thereby implicitly permits consideration of any and all measures of 
health risk which the Administrator, in his judgment, believes are 
---------------------------------------------------------------------------
appropriate to determining what will `protect the public health'.

See 54 FR 38057, September 14, 1989. Thus, the level of the MIR is only 
one factor to be weighed in determining acceptability of risk. The 
Benzene NESHAP explained that ``an MIR of approximately one in 10 
thousand should ordinarily be the upper end of the range of 
acceptability. As risks increase above this benchmark, they become 
presumptively less acceptable under CAA section 112, and would be 
weighed with the other health risk measures and information in making 
an overall judgment on acceptability. Or, the Agency may find, in a 
particular case, that a risk that includes an MIR less than the 
presumptively acceptable level is unacceptable in the light of other 
health risk factors.'' Id. at 38045. Similarly, with regard to the 
ample margin of safety analysis, the EPA stated in the Benzene NESHAP 
that: ``EPA believes the relative weight of the many factors that can 
be considered in selecting an ample margin of safety can only be 
determined for each specific source category. This occurs mainly 
because technological and economic factors (along with the health-
related factors) vary from source category to source category.'' Id. at 
38061. We also consider the uncertainties associated with the various 
risk analyses, as discussed earlier in this preamble, in our 
determinations of acceptability and ample margin of safety.
    The EPA notes that it has not considered certain health information 
to date in making residual risk determinations. At this time, we do not 
attempt to quantify the HAP risk that may be associated with emissions 
from other facilities that do not include the source category under 
review, mobile source emissions, natural source emissions, persistent 
environmental pollution, or atmospheric transformation in the vicinity 
of the sources in the category.
    The EPA understands the potential importance of considering an 
individual's total exposure to HAP in addition to considering exposure 
to HAP emissions from the source category and facility. We recognize 
that such consideration may be particularly important when assessing 
noncancer risk, where pollutant-specific exposure health reference 
levels (e.g., reference concentrations (RfCs)) are based on the 
assumption that thresholds exist for adverse health effects. For 
example, the EPA recognizes that, although exposures attributable to 
emissions from a source category or facility alone may not indicate the 
potential for increased risk of adverse noncancer health effects in a 
population, the exposures resulting from emissions from the facility in 
combination with emissions from all of the other sources (e.g., other 
facilities) to which an individual is exposed may be sufficient to 
result in an increased risk of adverse noncancer health effects. In May 
2010, the Science Advisory Board (SAB) advised the EPA ``that RTR 
assessments will be most useful to decision makers and communities if 
results are presented in the broader context of aggregate and 
cumulative risks, including background concentrations and contributions 
from other sources in the area.'' \4\
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    \4\ Recommendations of the SAB RTR Panel are provided in their 
report, which is available at: https://yosemite.epa.gov/sab/
sabproduct.nsf/4AB3966E263D943A8525771F00668381/$File/EPA-SAB-10-
007-unsigned.pdf.
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    In response to the SAB recommendations, the EPA incorporates 
cumulative risk analyses into its RTR risk assessments, including those 
reflected in this proposal. The Agency (1) conducts facility-wide 
assessments, which include source category emission points, as well as 
other emission points within the facilities; (2) combines exposures 
from multiple sources in the same category that could affect the same 
individuals; and (3) for some persistent and bioaccumulative 
pollutants, analyzes the ingestion route of exposure. In addition, the 
RTR risk assessments consider aggregate cancer risk from all 
carcinogens and aggregated noncancer HQs for all noncarcinogens 
affecting the same target organ or target organ system.
    Although we are interested in placing source category and facility-
wide HAP risk in the context of total HAP risk from all sources 
combined in the vicinity of each source, we are concerned about the 
uncertainties of doing so. Estimates of total HAP risk from emission 
sources other than those that we have studied in depth during this RTR 
review would have significantly greater associated uncertainties than 
the source category or facility-wide estimates. Such aggregate or 
cumulative assessments would compound those uncertainties, making the 
assessments too unreliable.

B. How do we perform the technology review?

    Our technology review focuses on the identification and evaluation 
of developments in practices, processes, and control technologies that 
have occurred since the MACT standards were promulgated. Where we 
identify such developments, we analyze their technical feasibility, 
estimated costs, energy implications, and non-air environmental 
impacts. We also consider the emission reductions associated with 
applying each development. This analysis informs our decision of 
whether it is ``necessary'' to revise the emissions standards. In 
addition, we consider the appropriateness of applying controls to new 
sources versus retrofitting existing sources. For this exercise, we 
consider any of the following to be a ``development'':
     Any add-on control technology or other equipment that was 
not identified and considered during development of the original MACT 
standards;
     Any improvements in add-on control technology or other 
equipment (that were identified and considered during development of 
the original MACT standards) that could result in additional emissions 
reduction;
     Any work practice or operational procedure that was not 
identified or considered during development of the original MACT 
standards;
     Any process change or pollution prevention alternative 
that could be broadly applied to the industry and that was not 
identified or considered during development of the original MACT 
standards; and
     Any significant changes in the cost (including cost 
effectiveness) of applying controls (including controls the EPA 
considered during the development of the original MACT standards).

[[Page 20214]]

    In addition to reviewing the practices, processes, and control 
technologies that were considered at the time we originally developed 
the NESHAP, we review a variety of data sources in our investigation of 
potential practices, processes, or controls to consider. See sections 
II.C and II. D of this preamble for information on the specific data 
sources that were reviewed as part of the technology review.

C. How do we estimate post-MACT risk posed by the source category?

    In this section, we provide a complete description of the types of 
analyses that we generally perform during the risk assessment process. 
In some cases, we do not perform a specific analysis because it is not 
relevant. For example, in the absence of emissions of HAP known to be 
persistent and bioaccumulative in the environment (PB-HAP), we would 
not perform a multipathway exposure assessment. Where we do not perform 
an analysis, we state that we do not and provide the reason. While we 
present all of our risk assessment methods, we only present risk 
assessment results for the analyses actually conducted (see section 
IV.B of this preamble).
    The EPA conducts a risk assessment that provides estimates of the 
MIR for cancer posed by the HAP emissions from each source in the 
source category, the HI for chronic exposures to HAP with the potential 
to cause noncancer health effects, and the HQ for acute exposures to 
HAP with the potential to cause noncancer health effects. The 
assessment also provides estimates of the distribution of cancer risk 
within the exposed populations, cancer incidence, and an evaluation of 
the potential for an adverse environmental effect. The seven sections 
that follow this paragraph describe how we estimated emissions and 
conducted the risk assessment. The docket for this rulemaking contains 
the following document which provides more information on the risk 
assessment inputs and models: Residual Risk Assessment for the Engine 
Test Cells/Stands Source Category in Support of the 2019 Risk and 
Technology Review Proposed Rule. The methods used to assess risk (as 
described in the seven primary steps below) are consistent with those 
described by the EPA in the document reviewed by a panel of the EPA's 
SAB in 2009; \5\ and described in the SAB review report issued in 2010. 
They are also consistent with the key recommendations contained in that 
report.
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    \5\ U.S. EPA. Risk and Technology Review (RTR) Risk Assessment 
Methodologies: For Review by the EPA's Science Advisory Board with 
Case Studies--MACT I Petroleum Refining Sources and Portland Cement 
Manufacturing, June 2009. EPA-452/R-09-006. https://www3.epa.gov/airtoxics/rrisk/rtrpg.html.
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1. How did we estimate actual emissions and identify the emissions 
release characteristics?
    The list of facilities that are subject to 40 CFR part 63, subpart 
PPPPP, was developed using the ECHO database, the 2014 NEI and the 
facility list developed for the promulgation of the 2003 NESHAP. 
Facilities with engine test cells/stands were identified in the 2014 
NEI records by their SCC or NAICS codes. The facility list was then 
refined using air permit information to determine whether the facility 
was a major source of HAP and subject to 40 CFR part 63, subpart PPPPP. 
The EPA emailed the list to several trade organizations as part of an 
outreach effort to the industry. The EPA Regional offices and state and 
local air pollution control agencies were asked to review the list and 
provide corrections as necessary. The DoD and NASA were also consulted 
and provided information for engine testing facilities located at 
research sites and military bases. Changes to the facility list were 
made based on the new information received. The final risk modeling 
datafile included 59 facilities, each with one or more engine test 
cell/stand. We are interested in your comments on the development of 
the facility list used in our analysis. For more details on the 
facility list development, see the memorandum titled Emissions Data 
Used for the Engine Test Cells/Stands Residual Risk Modeling File, in 
the docket for this rulemaking (Docket ID No. EPA-HQ-OAR-2018-0753).
    To determine which HAP should be modeled, we reviewed NEI emissions 
data and several other relevant sources to identify the principal HAP 
emitted.6 7 8 9 Because the type and quantity of emissions 
are related to the engine type and fuel combusted, we developed a list 
of HAP for each engine type and fuel combination. The organic HAP 
selected for turbines and reciprocating engines are formaldehyde, 
acetaldehyde, acrolein, 1,3-butadiene, benzene, toluene, xylenes, and 
naphthalene. In addition to these eight listed organic HAP, for diesel-
fired turbines and reciprocating engines the following metal HAP 
compounds were also listed: Arsenic, beryllium, cadmium, chromium, 
cobalt, lead, manganese, mercury, nickel, and selenium. The eight 
organic HAP were modeled for all test cells/stands used for testing 
turbines and/or reciprocating engines. Metal HAP emissions are not 
expected from jet fuel-, kerosene-, naphtha-, natural gas-, or 
gasoline-fired engines. Hence, metal HAP emissions were included in the 
modeling file only for test cells/stands testing turbines and 
reciprocating engines that burn diesel or distillate fuels. Limited 
emissions information was available for rocket engines. Hence, we 
modeled only HAP reported to NEI by each of the seven facilities 
engaged in rocket testing. The HAP modeled varied by facility due to 
differences in the type of propellant used. The HAP modeled for rocket 
engine testing included organic HAP, metal HAP, chlorine, hydrogen 
chloride, and hydrogen fluoride.
---------------------------------------------------------------------------

    \6\ Memorandum from Melanie Taylor (Alpha-Gamma Technologies, 
Inc.) to Sims Roy (U.S. EPA OAQPS), Emissions Data for Reciprocating 
Internal Combustion Engines, February 4, 2002.
    \7\ Compilation of Air Pollutant Emissions Factors, AP-42, Fifth 
Edition, Volume 1: Stationary Point and Area Sources, U.S. 
Environmental Protection Agency, Research Triangle Park, NC, January 
1995.
    \8\ Web Factor and Information Retrieval System (WebFire), U.S. 
Environmental Protection Agency (https://cfpub.epa.gov/webfire/).
    \9\ U.S. EPA SPECIATE Database (version 4.5), available at 
https://www.epa.gov/air-emissions-modeling/speciate-version-45-through-40.
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    We compiled the actual emissions data using the following four-step 
approach. Step 1--where possible, the actual emissions from the 2014 
NEI and the 2016 questionnaires were used for the very few facilities 
that reported HAP emissions to either NEI or in their completed 2016 
questionnaires. For facilities where HAP data were not available from 
these sources, we proceeded to step 2 (for facilities that submitted 
2016 questionnaires) and step 3 for all others.
    Step 2--As noted above, facilities that completed the 2016 
questionnaire were asked to provide information on the types and 
quantities of each fuel consumed during engine testing. HAP emissions 
for these facilities, when not directly reported to NEI or in the 
questionnaire, were calculated by multiplying the fuel usage reported 
in the questionnaire by an emission factor. The emission factors used 
to calculate emissions were obtained from three 
sources.10 11 12 Where a reliable emissions factor for a HAP 
was not available, we calculated emissions of VOC and filterable 
particulate matter with diameter less than 10 microns (PM10) 
emissions using emission factors, and then used the VOC and 
PM10

[[Page 20215]]

emissions values in step 3 to calculate HAP emissions.
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    \10\ Memorandum on Emissions Data for RICE, Alpha-Gamma 
Technologies, Inc, to U.S. EPA, 2002.
    \11\ Speciation Profiles and Toxic Emission Factors for Nonroad 
Engines, Table 13.
    \12\ AP-42, Section 3.
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    Step 3--For those facilities that either reported VOC emissions to 
the 2014 NEI or for which we were able to calculate VOC emissions using 
fuel data from the 2016 questionnaire, we calculated organic HAP 
emissions by multiplying the VOC emissions by a speciation factor. 
Similarly, the metal HAP emissions were calculated by multiplying the 
PM10 emissions (either reported in the 2014 NEI or 
calculated from 2016 questionnaire data) by a metal HAP speciation 
factor. The speciation factors used were based on speciation profiles 
from EPA's SPECIATE database.\13\ Where no speciation profiles were 
available in SPECIATE, we developed speciation factors using AP-42 
emission factors. For those engine/fuel combinations where no organic 
HAP speciation profiles or AP-42 emission factors existed, we developed 
speciation factors using the average HAP-to-VOC ratio based on the 
available emissions data for sources operating under the same SCC. The 
same approach was used to develop metal HAP speciation factors using 
the average of the HAP-to-PM10 ratio using the available 
PM10 and HAP data for other sources operating under the same 
SCC.
---------------------------------------------------------------------------

    \13\ SPECIATE is the EPA's repository of volatile organic gas 
and particulate matter (PM) speciation profiles of air pollution 
sources.
---------------------------------------------------------------------------

    Step 4--Where data needed for steps 1 through 3 were not available, 
we based the HAP emissions on either:
    (1) The HAP emissions from other similar test cells/stands located 
at the same facility and operating under the same SCC; or
    (2) The HAP emissions from other similar test cells/stands located 
at a different facility that operate under the same SCC.
    An average annual emissions value was used where emissions data for 
more than one test cell/stand was available.
    Mercury emissions were modeled as three different species: Gaseous 
elemental mercury, gaseous divalent mercury, and particulate divalent 
mercury. Chromium emissions were modeled as hexavalent chromium and 
trivalent chromium. We used emissions for total mercury and total 
chromium determined by using the methods outlined above, in combination 
with speciation factors from the EPA's SPECIATE, to calculate the 
emissions of each species. The SPECIATE database contains source-
specific, weight-fraction emission speciation profiles. The total 
mercury emissions were multiplied by the speciation factors of 0.5 for 
elemental mercury, 0.30 for gaseous divalent mercury, and 0.20 for 
particulate divalent mercury. The total chromium emissions were 
multiplied by speciation factors of 0.18 for hexavalent chromium and 
0.82 for trivalent chromium.
2. How did we estimate MACT-allowable emissions?
    The available emissions data in the RTR emissions dataset include 
estimates of the mass of HAP emitted during a specified annual time 
period. These ``actual'' emission levels are often lower than the 
emission levels allowed under the requirements of the current MACT 
standards. The emissions allowed under the MACT standards are referred 
to as the ``MACT-allowable'' emissions. We discussed the consideration 
of both MACT-allowable and actual emissions in the final Coke Oven 
Batteries RTR (70 FR 19998-19999, April 15, 2005) and in the proposed 
and final Hazardous Organic NESHAP RTR (71 FR 34428, June 14, 2006, and 
71 FR 76609, December 21, 2006, respectively). In those actions, we 
noted that assessing the risk at the MACT-allowable level is inherently 
reasonable since that risk reflects the maximum level facilities could 
emit and still comply with national emission standards. We also 
explained that it is reasonable to consider actual emissions, where 
such data are available, in both steps of the risk analysis, in 
accordance with the Benzene NESHAP approach. (54 FR 38044, September 
14, 1989.)
    Generally, allowable emissions for risk modeling are set equal to 
the current emission limits included in the rule. For this NESHAP, 
however, there are no emission limits for existing engine test cells/
stands or for new test cells/stands used for testing combustion 
turbines, rockets, and internal combustion engines with rated power 
less than 25 hp. Although there are limits for new and reconstructed 
engine test cells/stands used to test internal combustion engines rated 
at 25 hp and above, only seven engine test cells/stands facilities have 
been constructed or reconstructed since the NESHAP was proposed in 
2002. Thus, 52 of the 59 affected facilities are not subject to 
emission limits. Because most engine test cells/stands are not subject 
to emission limits and the emissions from engine test cells/stands can 
be variable, we have taken a conservative approach to estimating the 
allowable emissions for this source category. We estimated the 
allowable emissions at 4.5 times the actual emissions that were 
determined using the methods as described in section III.C.1 of this 
preamble. The 4.5 multiplier was determined based on data provided by 
facilities responding to our 2016 questionnaire that showed most 
facilities operate their engine test cells/stands at slightly less than 
50 percent of their maximum potential. By setting the allowable 
multiplier at half the acute multiplier of 9.5, the estimated allowable 
emissions included in the modeling datafile are conservative estimates 
that take into consideration the potential variability in emissions 
from this source category.
3. How do we conduct dispersion modeling, determine inhalation 
exposures, and estimate individual and population inhalation risk?
    Both long-term and short-term inhalation exposure concentrations 
and health risk from the source category addressed in this proposal 
were estimated using the Human Exposure Model (HEM-3).\14\ The HEM-3 
performs three primary risk assessment activities: (1) Conducting 
dispersion modeling to estimate the concentrations of HAP in ambient 
air; (2) estimating long-term and short-term inhalation exposures to 
individuals residing within 50 kilometers (km) of the modeled sources; 
and (3) estimating individual and population-level inhalation risk 
using the exposure estimates and quantitative dose-response 
information.
---------------------------------------------------------------------------

    \14\ For more information about HEM-3, go to https://www.epa.gov/fera/risk-assessment-and-modeling-human-exposure-model-hem.
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a. Dispersion Modeling
    The air dispersion model AERMOD, used by the HEM-3 model, is one of 
the EPA's preferred models for assessing air pollutant concentrations 
from industrial facilities.\15\ To perform the dispersion modeling and 
to develop the preliminary risk estimates, HEM-3 draws on three data 
libraries. The first is a library of meteorological data, which is used 
for dispersion calculations. This library includes 1 year (2016) of 
hourly surface and upper air observations from 824 meteorological 
stations, selected to provide coverage of the United States and Puerto 
Rico. A second library of United States Census Bureau census block \16\ 
internal point locations and populations provides the basis of human 
exposure calculations (U.S. Census, 2010). In addition, for each census 
block, the census library includes the elevation and controlling

[[Page 20216]]

hill height, which are also used in dispersion calculations. A third 
library of pollutant-specific dose-response values is used to estimate 
health risk. These are discussed below.
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    \15\ U.S. EPA. Revision to the Guideline on Air Quality Models: 
Adoption of a Preferred General Purpose (Flat and Complex Terrain) 
Dispersion Model and Other Revisions (70 FR 68218, November 9, 
2005).
    \16\ A census block is the smallest geographic area for which 
census statistics are tabulated.
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b. Risk From Chronic Exposure to HAP
    In developing the risk assessment for chronic exposures, we use the 
estimated annual average ambient air concentrations of each HAP emitted 
by each source in the source category. The HAP air concentrations at 
each nearby census block centroid located within 50 km of the facility 
are a surrogate for the chronic inhalation exposure concentration for 
all the people who reside in that census block. A distance of 50 km is 
consistent with both the analysis supporting the 1989 Benzene NESHAP 
(54 FR 38044, September 14, 1989) and the limitations of Gaussian 
dispersion models, including AERMOD.
    For each facility, we calculate the MIR as the cancer risk 
associated with a continuous lifetime (24 hours per day, 7 days per 
week, 52 weeks per year, 70 years) exposure to the maximum 
concentration at the centroid of each inhabited census block. We 
calculate individual cancer risk by multiplying the estimated lifetime 
exposure to the ambient concentration of each HAP (in micrograms per 
cubic meter ([mu]g/m\3\)) by its unit risk estimate (URE). The URE is 
an upper-bound estimate of an individual's incremental risk of 
contracting cancer over a lifetime of exposure to a concentration of 1 
microgram of the pollutant per cubic meter of air. For residual risk 
assessments, we generally use UREs from the 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 similar to that used by the EPA, we may use such 
dose-response values in place of, or in addition to, other values, if 
appropriate. The pollutant-specific dose-response values used to 
estimate health risk are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
    To estimate individual lifetime cancer risks associated with 
exposure to HAP emissions from each facility in the source category, we 
sum the risks for each of the carcinogenic HAP \17\ emitted by the 
modeled facility. We estimate cancer risk at every census block within 
50 km of every facility in the source category. The MIR is the highest 
individual lifetime cancer risk estimated for any of those census 
blocks. In addition to calculating the MIR, we estimate the 
distribution of individual cancer risks for the source category by 
summing the number of individuals within 50 km of the sources whose 
estimated risk falls within a specified risk range. We also estimate 
annual cancer incidence by multiplying the estimated lifetime cancer 
risk at each census block by the number of people residing in that 
block, summing results for all of the census blocks, and then dividing 
this result by a 70-year lifetime.
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    \17\ The EPA's 2005 Guidelines for Carcinogen Risk Assessment 
classifies carcinogens as: ``carcinogenic to humans,'' ``likely to 
be carcinogenic to humans,'' and ``suggestive evidence of 
carcinogenic potential.'' These classifications also coincide with 
the terms ``known carcinogen, probable carcinogen, and possible 
carcinogen,'' respectively, which are the terms advocated in the 
EPA's Guidelines for Carcinogen Risk Assessment, published in 1986 
(51 FR 33992, September 24, 1986). In August 2000, the document, 
Supplemental Guidance for Conducting Health Risk Assessment of 
Chemical Mixtures (EPA/630/R-00/002), was published as a supplement 
to the 1986 document. Copies of both documents can be obtained from 
https://cfpub.epa.gov/ncea/risk/recordisplay.cfm?deid=20533&CFID=70315376&CFTOKEN=71597944. Summing 
the risk of these individual compounds to obtain the cumulative 
cancer risk is an approach that was recommended by the EPA's SAB in 
their 2002 peer review of the EPA's National Air Toxics Assessment 
(NATA) titled NATA--Evaluating the National-scale Air Toxics 
Assessment 1996 Data--an SAB Advisory, available at https://
yosemite.epa.gov/sab/sabproduct.nsf/
214C6E915BB04E14852570CA007A682C/$File/ecadv02001.pdf.
---------------------------------------------------------------------------

    To assess the risk of noncancer health effects from chronic 
exposure to HAP, we calculate either an HQ or a target organ-specific 
hazard index (TOSHI). We calculate an HQ when a single noncancer HAP is 
emitted. Where more than one noncancer HAP is emitted, we sum the HQ 
for each of the HAP that affects a common target organ or target organ 
system to obtain a TOSHI. The HQ is the estimated exposure divided by 
the chronic noncancer dose-response value, which is a value selected 
from one of several sources. The preferred chronic noncancer dose-
response value is the EPA RfC, defined as ``an estimate (with 
uncertainty spanning perhaps an order of magnitude) of a continuous 
inhalation exposure to the human population (including sensitive 
subgroups) that is likely to be without an appreciable risk of 
deleterious effects during a lifetime'' (https://iaspub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&vocabName=IRIS%20Glossary). In cases where an RfC 
from the EPA's IRIS is not available or where the EPA determines that 
using a value other than the RfC is appropriate, the chronic noncancer 
dose-response value can be a value from the following prioritized 
sources, which define their dose-response values similarly to the EPA: 
(1) The Agency for Toxic Substances and Disease Registry (ATSDR) 
Minimum Risk Level (https://www.atsdr.cdc.gov/mrls/index.asp); (2) the 
CalEPA Chronic Reference Exposure Level (REL) (https://oehha.ca.gov/air/crnr/notice-adoption-air-toxics-hot-spots-program-guidance-manual-preparation-health-risk-0); or (3), as noted above, a scientifically 
credible dose-response value that has been developed in a manner 
consistent with the EPA guidelines and has undergone a peer review 
process similar to that used by the EPA. The pollutant-specific dose-
response values used to estimate health risks are available at https://www.epa.gov/fera/dose-response-assessment-assessing-health-risks-associated-exposure-hazardous-air-pollutants.
c. Risk From Acute Exposure to HAP That May Cause Health Effects Other 
Than Cancer
    For each HAP for which appropriate acute inhalation dose-response 
values are available, the EPA also assesses the potential health risks 
due to acute exposure. For these assessments, the EPA makes 
conservative assumptions about emission rates, meteorology, and 
exposure location. We use the peak hourly emission rate,\18\ worst-case 
dispersion conditions, and, in accordance with our mandate under 
section 112 of the CAA, the point of highest off-site exposure to 
assess the potential risk to the maximally exposed individual.
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    \18\ In the absence of hourly emission data, we develop 
estimates of maximum hourly emission rates by multiplying the 
average actual annual emissions rates by a factor (either a 
category-specific factor or a default factor of 10) to account for 
variability. This is documented in Residual Risk Assessment for 
Engine Test Cells/Stands Source Category in Support of the 2019 Risk 
and Technology Review Proposed Rule and in Appendix 5 of the report: 
Analysis of Data on Short-term Emission Rates Relative to Long-term 
Emission Rates. Both are available in the docket for this 
rulemaking.
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    To characterize the potential health risks associated with 
estimated acute inhalation exposures to a HAP, we generally use 
multiple acute dose-response values, including acute RELs, acute 
exposure guideline levels (AEGLs), and emergency response

[[Page 20217]]

planning guidelines (ERPG) for 1-hour exposure durations), if 
available, to calculate acute HQs. The acute HQ is calculated by 
dividing the estimated acute exposure by the acute dose-response value. 
For each HAP for which acute dose-response values are available, the 
EPA calculates acute HQs.
    An acute REL is defined as ``the concentration level at or below 
which no adverse health effects are anticipated for a specified 
exposure duration.'' \19\ Acute RELs are based on the most sensitive, 
relevant, adverse health effect reported in the peer-reviewed medical 
and toxicological literature. They are designed to protect the most 
sensitive individuals in the population through the inclusion of 
margins of safety. Because margins of safety are incorporated to 
address data gaps and uncertainties, exceeding the REL does not 
automatically indicate an adverse health impact. AEGLs represent 
threshold exposure limits for the general public and are applicable to 
emergency exposures ranging from 10 minutes to 8 hours.\20\ They are 
guideline levels for ``once-in-a-lifetime, short-term exposures to 
airborne concentrations of acutely toxic, high-priority chemicals.'' 
Id. at 21. The AEGL-1 is specifically defined as ``the airborne 
concentration (expressed as ppm (parts per million) or mg/m\3\ 
(milligrams per cubic meter)) of a substance above which it is 
predicted that the general population, including susceptible 
individuals, could experience notable discomfort, irritation, or 
certain asymptomatic nonsensory effects. However, the effects are not 
disabling and are transient and reversible upon cessation of 
exposure.'' The document also notes that ``Airborne concentrations 
below AEGL-1 represent exposure levels that can produce mild and 
progressively increasing but transient and nondisabling odor, taste, 
and sensory irritation or certain asymptomatic, nonsensory effects.'' 
Id. AEGL-2 are defined as ``the airborne concentration (expressed as 
parts per million or milligrams per cubic meter) of a substance above 
which it is predicted that the general population, including 
susceptible individuals, could experience irreversible or other 
serious, long-lasting adverse health effects or an impaired ability to 
escape.'' Id.
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    \19\ CalEPA issues acute RELs as part of its Air Toxics Hot 
Spots Program, and the 1-hour and 8-hour values are documented in 
Air Toxics Hot Spots Program Risk Assessment Guidelines, Part I, The 
Determination of Acute Reference Exposure Levels for Airborne 
Toxicants, which is available at https://oehha.ca.gov/air/general-info/oehha-acute-8-hour-and-chronic-reference-exposure-level-rel-summary.
    \20\ National Academy of Sciences, 2001. Standing Operating 
Procedures for Developing Acute Exposure Levels for Hazardous 
Chemicals, page 2. Available at https://www.epa.gov/sites/production/files/2015-09/documents/sop_final_standing_operating_procedures_2001.pdf. Note that the 
National Advisory Committee for Acute Exposure Guideline Levels for 
Hazardous Substances ended in October 2011, but the AEGL program 
continues to operate at the EPA and works with the National 
Academies to publish final AEGLs (https://www.epa.gov/aegl).
---------------------------------------------------------------------------

    ERPGs are ``developed for emergency planning and are intended as 
health-based guideline concentrations for single exposures to 
chemicals.'' \21\ Id. at 1. The ERPG-1 is defined as ``the maximum 
airborne concentration below which it is believed that nearly all 
individuals could be exposed for up to 1 hour without experiencing 
other than mild transient adverse health effects or without perceiving 
a clearly defined, objectionable odor.'' Id. at 2. Similarly, the ERPG-
2 is defined as ``the maximum airborne concentration below which it is 
believed that nearly all individuals could be exposed for up to one 
hour without experiencing or developing irreversible or other serious 
health effects or symptoms which could impair an individual's ability 
to take protective action.'' Id. at 1.
---------------------------------------------------------------------------

    \21\ ERPGS Procedures and Responsibilities. March 2014. American 
Industrial Hygiene Association. Available at: https://www.aiha.org/get-involved/AIHAGuidelineFoundation/EmergencyResponsePlanningGuidelines/Documents/ERPG%20Committee%20Standard%20Operating%20Procedures%20%20-%20March%202014%20Revision%20%28Updated%2010-2-2014%29.pdf.
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    An acute REL for 1-hour exposure durations is typically lower than 
its corresponding AEGL-1 and ERPG-1. Even though their definitions are 
slightly different, AEGL-1s are often the same as the corresponding 
ERPG-1s, and AEGL-2s are often equal to ERPG-2s. The maximum HQs from 
our acute inhalation screening risk assessment typically result when we 
use the acute REL for a HAP. In cases where the maximum acute HQ 
exceeds 1, we also report the HQ based on the next highest acute dose-
response value (usually the AEGL-1 and/or the ERPG-1).
    For the Engine Test Cells/Stands source category, annual actual 
emission values were multiplied by a conservative factor of 9.5 instead 
of the default emissions multiplier of 10. This source category 
specific factor was developed using activity data collected from the 
2016 questionnaire. A further discussion of why this factor was chosen 
can be found in the memorandum, Emissions Data and Acute Risk Factor 
Used in Residual Risk Modeling: Engine Test Cell/Stands, available in 
the docket for this rulemaking.
    In our acute inhalation screening risk assessment, acute impacts 
are deemed negligible for HAP for which acute HQs are less than or 
equal to 1 (even under the conservative assumptions of the screening 
assessment), and no further analysis is performed for these HAP. In 
cases where an acute HQ from the screening step is greater than 1, we 
consider additional site-specific data to develop a more refined 
estimate of the potential for acute exposures of concern. For this 
source category, the data refinements employed consisted of looking at 
the impact of acute risks at only off source category property 
locations. These refinements are discussed more fully in the Residual 
Risk Assessment for the Engine Test Cells/Stands Source Category in 
Support of the 2019 Risk and Technology Review Proposed Rule, which is 
available in the docket for this source category.
4. How do we conduct the multipathway exposure and risk screening 
assessment?
    The EPA conducts a tiered screening assessment examining the 
potential for significant human health risks due to exposures via 
routes other than inhalation (i.e., ingestion). We first determine 
whether any sources in the source category emit any HAP known to be PB-
HAP, as identified in the EPA's Air Toxics Risk Assessment Library (see 
Volume 1, Appendix D, at https://www.epa.gov/fera/risk-assessment-and-modeling-air-toxics-risk-assessment-reference-library.
    For the Engine Test Cells/Stands source category, we identified PB-
HAP emissions of lead compounds, cadmium compounds, arsenic compounds, 
mercury compounds, and polycyclic organic matter (POM) (of which 
polycyclic aromatic hydrocarbons is a subset), so we proceeded to the 
next step of the evaluation. In this step, we determine whether the 
facility-specific emission rates of the emitted PB-HAP are large enough 
to create the potential for significant human health risk through 
ingestion exposure under reasonable worst-case conditions. To 
facilitate this step, we use previously developed screening threshold 
emission rates for several PB-HAP that are based on a hypothetical 
upper-end screening exposure scenario developed for use in conjunction 
with the EPA's Total Risk Integrated Methodology. Fate, Transport, and 
Ecological Exposure (TRIM.FaTE) model. The PB-HAP with screening 
threshold emission rates are arsenic compounds, cadmium compounds, 
chlorinated dibenzodioxins and furans, mercury compounds, and

[[Page 20218]]

POM. Based on the EPA estimates of toxicity and bioaccumulation 
potential, the pollutants above represent a conservative list for 
inclusion in multipathway risk assessments for RTR rules. (See Volume 
1, Appendix D at https://www.epa.gov/sites/production/files/201308/documents/volume_1_reflibrary.pdf). In this assessment, we compare the 
facility-specific emission rates of these PB-HAP to the screening 
threshold emission rates for each PB-HAP to assess the potential for 
significant human health risks via the ingestion pathway. We call this 
application of the TRIM.FaTE model the Tier 1 screening assessment. The 
ratio of a facility's actual emission rate to the Tier 1 screening 
threshold emission rate is a ``screening value.''
    We derive the Tier 1 screening threshold emission rates for these 
PB-HAP (other than lead compounds) to correspond to a maximum excess 
lifetime cancer risk of 1-in-1 million (i.e., for arsenic compounds, 
polychlorinated dibenzodioxins and furans and POM) or, for HAP that 
cause noncancer health effects (i.e., cadmium compounds and mercury 
compounds), a maximum HQ of 1. If the emission rate of any one PB-HAP 
or combination of carcinogenic PB-HAP in the Tier 1 screening 
assessment exceeds the Tier 1 screening threshold emission rate for any 
facility (i.e., the screening value is greater than 1), we conduct a 
second screening assessment, which we call the Tier 2 screening 
assessment.
    In the Tier 2 screening assessment, the location of each facility 
that exceeds a Tier 1 screening threshold emission rate is used to 
refine the assumptions associated with the Tier 1 fisher and farmer 
exposure scenarios at that facility. A key assumption in the Tier 1 
screening assessment is that a lake and/or farm is located near the 
facility. As part of the Tier 2 screening assessment, we use a U.S. 
Geological Survey (USGS) database to identify actual waterbodies within 
50 km of each facility. We also examine the differences between local 
meteorology near the facility and the meteorology used in the Tier 1 
screening assessment. We then adjust the previously-developed Tier 1 
screening threshold emission rates for each PB-HAP for each facility 
based on an understanding of how exposure concentrations estimated for 
the screening scenario change with the use of local meteorology and 
USGS waterbody data. If the PB-HAP emission rates for a facility exceed 
the Tier 2 screening threshold emission rates and data are available, 
we may conduct a Tier 3 screening assessment. If PB-HAP emission rates 
do not exceed a Tier 2 screening value of 1, we consider those PB-HAP 
emissions to pose risks below a level of concern.
    There are several analyses that can be included in a Tier 3 
screening assessment, depending upon the extent of refinement 
warranted, including validating that the lakes are fishable, 
considering plume-rise to estimate emissions lost above the mixing 
layer, and considering hourly effects of meteorology and plume rise on 
chemical fate and transport. If the Tier 3 screening assessment 
indicates that risks above levels of concern cannot be ruled out, the 
EPA may further refine the screening assessment through a site-specific 
assessment.
    In evaluating the potential multipathway risk from emissions of 
lead compounds, rather than developing a screening threshold emission 
rate, we compare maximum estimated chronic inhalation exposure 
concentrations to the level of the current National Ambient Air Quality 
Standard (NAAQS) for lead.\22\ Values below the level of the primary 
(health-based) lead NAAQS are considered to have a low potential for 
multipathway risk.
---------------------------------------------------------------------------

    \22\ In doing so, the EPA notes that the legal standard for a 
primary NAAQS--that a standard is requisite to protect public health 
and provide an adequate margin of safety (CAA section 109(b))--
differs from the CAA section 112(f) standard (requiring, among other 
things, that the standard provide an ``ample margin of safety to 
protect public health''). However, the primary lead NAAQS is a 
reasonable measure of determining risk acceptability (i.e., the 
first step of the Benzene NESHAP analysis) since it is designed to 
protect the most susceptible group in the human population--
children, including children living near major lead emitting 
sources. 73 FR 67002/3; 73 FR 67000/3; 73 FR 67005/1. In addition, 
applying the level of the primary lead NAAQS at the risk 
acceptability step is conservative, since that primary lead NAAQS 
reflects an adequate margin of safety.
---------------------------------------------------------------------------

    For further information on the multipathway assessment approach, 
see the Residual Risk Assessment for the Engine Test Cells/Stands 
Source Category in Support of the Risk and Technology Review 2019 
Proposed Rule, which is available in the docket for this action.
5. How do we conduct the environmental risk screening assessment?
a. Adverse Environmental Effect, Environmental HAP, and Ecological 
Benchmarks
    The EPA conducts a screening assessment to examine the potential 
for an adverse environmental effect as required under section 
112(f)(2)(A) of the CAA. Section 112(a)(7) of the CAA defines ``adverse 
environmental effect'' as ``any significant and widespread adverse 
effect, which may reasonably be anticipated, to wildlife, aquatic life, 
or other natural resources, including adverse impacts on populations of 
endangered or threatened species or significant degradation of 
environmental quality over broad areas.''
    The EPA focuses on eight HAP, which are referred to as 
``environmental HAP,'' in its screening assessment: Six PB-HAP and two 
acid gases. The PB-HAP included in the screening assessment are arsenic 
compounds, cadmium compounds, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), and lead compounds. The acid 
gases included in the screening assessment are hydrochloric acid (HCl) 
and hydrogen fluoride (HF).
    HAP that persist and bioaccumulate are of particular environmental 
concern because they accumulate in the soil, sediment, and water. The 
acid gases, HCl and HF, are included due to their well-documented 
potential to cause direct damage to terrestrial plants. In the 
environmental risk screening assessment, we evaluate the following four 
exposure media: Terrestrial soils, surface water bodies (includes 
water-column and benthic sediments), fish consumed by wildlife, and 
air. Within these four-exposure media, we evaluate nine ecological 
assessment endpoints, which are defined by the ecological entity and 
its attributes. For PB-HAP (other than lead), both community-level and 
population-level endpoints are included. For acid gases, the ecological 
assessment evaluated is terrestrial plant communities.
    An ecological benchmark represents a concentration of HAP that has 
been linked to a particular environmental effect level. For each 
environmental HAP, we identified the available ecological benchmarks 
for each assessment endpoint. We identified, where possible, ecological 
benchmarks at the following effect levels: Probable effect levels, 
lowest-observed-adverse-effect level, and no-observed-adverse-effect 
level. In cases where multiple effect levels were available for a 
particular PB-HAP and assessment endpoint, we use all of the available 
effect levels to help us to determine whether ecological risks exist 
and, if so, whether the risks could be considered significant and 
widespread.
    For further information on how the environmental risk screening 
assessment was conducted, including a discussion of the risk metrics 
used, how the environmental HAP were identified, and how the ecological 
benchmarks were selected, see Appendix 9 of the Residual Risk 
Assessment for the Engine Test Cells/Stands Source Category in

[[Page 20219]]

Support of the Risk and Technology Review 2019 Proposed Rule, which is 
available in the docket for this action.
b. Environmental Risk Screening Methodology
    For the environmental risk screening assessment, the EPA first 
determined whether any facilities in the Engine Test Cells/Stands 
source category emitted any of the environmental HAP (cadmium, dioxins, 
POM, mercury [both inorganic mercury and methylmercury], arsenic, and 
lead). For the Engine Test Cells/Stands source category, we identified 
emissions of arsenic, cadmium, HCl, HF, lead, mercury, and POMs. 
Because one or more of the environmental HAP evaluated are emitted by 
at least one facility in the source category, we proceeded to the 
second step of the evaluation.
c. PB-HAP Methodology
    The environmental screening assessment includes six PB-HAP, arsenic 
compounds, cadmium compounds, dioxins/furans, POM, mercury (both 
inorganic mercury and methyl mercury), and lead compounds. With the 
exception of lead, the environmental risk screening assessment for PB-
HAP consists of three tiers. The first tier of the environmental risk 
screening assessment uses the same health-protective conceptual model 
that is used for the Tier 1 human health screening assessment. 
TRIM.FaTE model simulations were used to back-calculate Tier 1 
screening threshold emission rates. The screening threshold emission 
rates represent the emission rate in tons of pollutant per year that 
results in media concentrations at the facility that equal the relevant 
ecological benchmark. To assess emissions from each facility in the 
category, the reported emission rate for each PB-HAP was compared to 
the Tier 1 screening threshold emission rate for that PB-HAP for each 
assessment endpoint and effect level. If emissions from a facility do 
not exceed the Tier 1 screening threshold emission rate, the facility 
``passes'' the screening assessment, and, therefore, is not evaluated 
further under the screening approach. If emissions from a facility 
exceed the Tier 1 screening threshold emission rate, we evaluate the 
facility further in Tier 2.
    In Tier 2 of the environmental screening assessment, the screening 
threshold emission rates are adjusted to account for local meteorology 
and the actual location of lakes in the vicinity of facilities that did 
not pass the Tier 1 screening assessment. For soils, we evaluate the 
average soil concentration for all soil parcels within a 7.5-km radius 
for each facility and PB-HAP. For the water, sediment, and fish tissue 
concentrations, the highest value for each facility for each pollutant 
is used. If emission concentrations from a facility do not exceed the 
Tier 2 screening threshold emission rate, the facility ``passes'' the 
screening assessment and typically is not evaluated further. If 
emissions from a facility exceed the Tier 2 screening threshold 
emission rate, we evaluate the facility further in Tier 3.
    As in the multipathway human health risk assessment, in Tier 3 of 
the environmental screening assessment, we examine the suitability of 
the lakes around the facilities to support life and remove those that 
are not suitable (e.g., lakes that have been filled in or are 
industrial ponds), adjust emissions for plume-rise, and conduct hour-
by-hour time-series assessments. If these Tier 3 adjustments to the 
screening threshold emission rates still indicate the potential for an 
adverse environmental effect (i.e., facility emission rate exceeds the 
screening threshold emission rate), we may elect to conduct a more 
refined assessment using more site-specific information. If, after 
additional refinement, the facility emission rate still exceeds the 
screening threshold emission rate, the facility may have the potential 
to cause an adverse environmental effect.
    To evaluate the potential for an adverse environmental effect from 
lead, we compared the average modeled air concentrations (from HEM-3) 
of lead around each facility in the source category to the level of the 
secondary NAAQS for lead. The secondary lead NAAQS is a reasonable 
means of evaluating environmental risk because it is set to provide 
substantial protection against adverse welfare effects which can 
include ``effects on soils, water, crops, vegetation, man-made 
materials, animals, wildlife, weather, visibility and climate, damage 
to and deterioration of property, and hazards to transportation, as 
well as effects on economic values and on personal comfort and well-
being.''
d. Acid Gas Environmental Risk Methodology
    The environmental screening assessment for acid gases evaluates the 
potential phytotoxicity and reduced productivity of plants due to 
chronic exposure to HF and HCl. The environmental risk screening 
methodology for acid gases is a single-tier screening assessment that 
compares modeled ambient air concentrations (from AERMOD) to the 
ecological benchmarks for each acid gas. To identify a potential 
adverse environmental effect (as defined in section 112(a)(7) of the 
CAA) from emissions of HF and HCl, we evaluate the following metrics: 
The size of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas, in acres and km\2\; the 
percentage of the modeled area around each facility that exceeds the 
ecological benchmark for each acid gas; and the area-weighted average 
screening value around each facility (calculated by dividing the area-
weighted average concentration over the 50-km modeling domain by the 
ecological benchmark for each acid gas). For further information on the 
environmental screening assessment approach, see Appendix 9 of the 
Residual Risk Assessment for the Engine Test Cells/Stands Source 
Category in Support of the Risk and Technology Review 2019 Proposed 
Rule, which is available in the docket for this action.
6. How do we conduct facility-wide assessments?
    To put the source category risks in context, we typically examine 
the risks from the entire ``facility,'' where the facility includes all 
HAP-emitting operations within a contiguous area and under common 
control. In other words, we examine the HAP emissions not only from the 
source category emission points of interest, but also emissions of HAP 
from all other emission sources at the facility for which we have data. 
For this source category, we conducted the facility-wide assessment 
using a dataset compiled from the 2014 NEI. The source category records 
of that NEI dataset were removed, evaluated, and updated as described 
in section II.C of this preamble (What data collection activities were 
conducted to support this action?). Once a quality assured source 
category dataset was available, it was placed back with the remaining 
records from the NEI for that facility. The facility-wide file was then 
used to analyze risks due to the inhalation of HAP that are emitted 
``facility-wide'' for the populations residing within 50 km of each 
facility, consistent with the methods used for the source category 
analysis described above. For these facility-wide risk analyses, the 
modeled source category risks were compared to the facility-wide risks 
to determine the portion of the facility-wide risks that could be 
attributed to the source category addressed in this proposal. We also 
specifically examined the facility that was associated with the highest 
estimate of risk and determined the percentage of that risk 
attributable to the source category of interest. The Residual

[[Page 20220]]

Risk Assessment for the Engine Test Cells/Stands Source Category in 
Support of the Risk and Technology Review 2019 Proposed Rule, available 
through the docket for this action, provides the methodology and 
results of the facility-wide analyses, including all facility-wide 
risks and the percentage of source category contribution to facility-
wide risks.
7. How do we consider uncertainties in risk assessment?
    Uncertainty and the potential for bias are inherent in all risk 
assessments, including those performed for this proposal. Although 
uncertainty exists, we believe that our approach, which used 
conservative tools and assumptions, ensures that our decisions are 
health and environmentally protective. A brief discussion of the 
uncertainties in the RTR emissions dataset, dispersion modeling, 
inhalation exposure estimates, and dose-response relationships follows 
below. Also included are those uncertainties specific to our acute 
screening assessments, multipathway screening assessments, and our 
environmental risk screening assessments. A more thorough discussion of 
these uncertainties is included in the Residual Risk Assessment for the 
Engine Test Cells/Stands Source Category in Support of the Risk and 
Technology Review 2019 Proposed Rule, which is available in the docket 
for this action. If a multipathway site-specific assessment was 
performed for this source category, a full discussion of the 
uncertainties associated with that assessment can be found in Appendix 
11 of that document, Site-Specific Human Health Multipathway Residual 
Risk Assessment Report.
a. Uncertainties in the RTR Emissions Dataset
    Although the development of the RTR emissions dataset involved 
quality assurance/quality control processes, the accuracy of emissions 
values will vary depending on the source of the data, the degree to 
which data are incomplete or missing, the degree to which assumptions 
made to complete the datasets are accurate, errors in emission 
estimates, and other factors. The emission estimates considered in this 
analysis generally are annual totals for certain years, and they do not 
reflect short-term fluctuations during the course of a year or 
variations from year to year. The estimates of peak hourly emission 
rates for the acute effects screening assessment were based on an 
emission adjustment factor applied to the average annual hourly 
emission rates, which are intended to account for emission fluctuations 
due to normal facility operations.
b. Uncertainties in Dispersion Modeling
    We recognize there is uncertainty in ambient concentration 
estimates associated with any model, including the EPA's recommended 
regulatory dispersion model, AERMOD. In using a model to estimate 
ambient pollutant concentrations, the user chooses certain options to 
apply. For RTR assessments, we select some model options that have the 
potential to overestimate ambient air concentrations (e.g., not 
including plume depletion or pollutant transformation). We select other 
model options that have the potential to underestimate ambient impacts 
(e.g., not including building downwash). Other options that we select 
have the potential to either under- or overestimate ambient levels 
(e.g., meteorology and receptor locations). On balance, considering the 
directional nature of the uncertainties commonly present in ambient 
concentrations estimated by dispersion models, the approach we apply in 
the RTR assessments should yield unbiased estimates of ambient HAP 
concentrations. We also note that the selection of meteorology dataset 
location could have an impact on the risk estimates. As we continue to 
update and expand our library of meteorological station data used in 
our risk assessments, we expect to reduce this variability.
c. Uncertainties in Inhalation Exposure Assessment
    Although every effort is made to identify all of the relevant 
facilities and emission points, as well as to develop accurate 
estimates of the annual emission rates for all relevant HAP, the 
uncertainties in our emission inventory likely dominate the 
uncertainties in the exposure assessment. Some uncertainties in our 
exposure assessment include human mobility, using the centroid of each 
census block, assuming lifetime exposure, and assuming only outdoor 
exposures. For most of these factors, there is neither an under nor 
overestimate when looking at the maximum individual risk or the 
incidence, but the shape of the distribution of risks may be affected. 
With respect to outdoor exposures, actual exposures may not be as high 
if people spend time indoors, especially for very reactive pollutants 
or larger particles. For all factors, we reduce uncertainty when 
possible. For example, with respect to census-block centroids, we 
analyze large blocks using aerial imagery and adjust locations of the 
block centroids to better represent the population in the blocks. We 
also add additional receptor locations where the population of a block 
is not well represented by a single location.
d. Uncertainties in Dose-Response Relationships
    There are uncertainties inherent in the development of the dose-
response values used in our risk assessments for cancer effects from 
chronic exposures and noncancer effects from both chronic and acute 
exposures. Some uncertainties are generally expressed quantitatively, 
and others are generally expressed in qualitative terms. We note, as a 
preface to this discussion, a point on dose-response uncertainty that 
is stated in the EPA's 2005 Guidelines for Carcinogen Risk Assessment; 
namely, that ``the primary goal of EPA actions is protection of human 
health; accordingly, as an Agency policy, risk assessment procedures, 
including default options that are used in the absence of scientific 
data to the contrary, should be health protective'' (the EPA's 2005 
Guidelines for Carcinogen Risk Assessment, page 1-7). This is the 
approach followed here as summarized in the next paragraphs.
    Cancer UREs used in our risk assessments are those that have been 
developed to generally provide an upper bound estimate of risk.\23\ 
That is, they represent a ``plausible upper limit to the true value of 
a quantity'' (although this is usually not a true statistical 
confidence limit). In some circumstances, the true risk could be as low 
as zero; however, in other circumstances the risk could be greater.\24\ 
Chronic noncancer RfC and reference dose (RfD) values represent chronic 
exposure levels that are intended to be health-protective levels. To 
derive dose-response values that are intended to be ``without 
appreciable risk,'' the methodology relies upon an uncertainty factor 
(UF) approach,\25\ which considers uncertainty, variability, and gaps 
in the available data. The UFs are applied to derive dose-response 
values that are intended to protect

[[Page 20221]]

against appreciable risk of deleterious effects.
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    \23\ IRIS glossary (https://ofmpub.epa.gov/sor_internet/registry/termreg/searchandretrieve/glossariesandkeywordlists/search.do?details=&glossaryName=IRIS%20Glossary).
    \24\ An exception to this is the URE for benzene, which is 
considered to cover a range of values, each end of which is 
considered to be equally plausible, and which is based on maximum 
likelihood estimates.
    \25\ See A Review of the Reference Dose and Reference 
Concentration Processes, U.S. EPA, December 2002, and Methods for 
Derivation of Inhalation Reference Concentrations and Application of 
Inhalation Dosimetry, U.S. EPA, 1994.
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    Many of the UFs used to account for variability and uncertainty in 
the development of acute dose-response values are quite similar to 
those developed for chronic durations. Additional adjustments are often 
applied to account for uncertainty in extrapolation from observations 
at one exposure duration (e.g., 4 hours) to derive an acute dose-
response value at another exposure duration (e.g., 1 hour). Not all 
acute dose-response values are developed for the same purpose, and care 
must be taken when interpreting the results of an acute assessment of 
human health effects relative to the dose-response value or values 
being exceeded. Where relevant to the estimated exposures, the lack of 
acute dose-response values at different levels of severity should be 
factored into the risk characterization as potential uncertainties.
    Uncertainty also exists in the selection of ecological benchmarks 
for the environmental risk screening assessment. We established a 
hierarchy of preferred benchmark sources to allow selection of 
benchmarks for each environmental HAP at each ecological assessment 
endpoint. We searched for benchmarks for three effect levels (i.e., no-
effects level, threshold-effect level, and probable effect level), but 
not all combinations of ecological assessment/environmental HAP had 
benchmarks for all three effect levels. Where multiple effect levels 
were available for a particular HAP and assessment endpoint, we used 
all of the available effect levels to help us determine whether risk 
exists and whether the risk could be considered significant and 
widespread.
    Although we make every effort to identify appropriate human health 
effect dose-response values for all pollutants emitted by the sources 
in this risk assessment, some HAP emitted by this source category are 
lacking dose-response assessments. Accordingly, these pollutants cannot 
be included in the quantitative risk assessment, which could result in 
quantitative estimates understating HAP risk. To help to alleviate this 
potential underestimate, where we conclude similarity with a HAP for 
which a dose-response value is available, we use that value as a 
surrogate for the assessment of the HAP for which no value is 
available. To the extent use of surrogates indicates appreciable risk, 
we may identify a need to increase priority for an IRIS assessment for 
that substance. We additionally note that, generally speaking, HAP of 
greatest concern due to environmental exposures and hazard are those 
for which dose-response assessments have been performed, reducing the 
likelihood of understating risk. Further, HAP not included in the 
quantitative assessment are assessed qualitatively and considered in 
the risk characterization that informs the risk management decisions, 
including consideration of HAP reductions achieved by various control 
options.
    For a group of compounds that are unspeciated (e.g., glycol 
ethers), we conservatively use the most protective dose-response value 
of an individual compound in that group to estimate risk. Similarly, 
for an individual compound in a group (e.g., ethylene glycol diethyl 
ether) that does not have a specified dose-response value, we also 
apply the most protective dose-response value from the other compounds 
in the group to estimate risk.
e. Uncertainties in Acute Inhalation Screening Assessments
    In addition to the uncertainties highlighted above, there are 
several factors specific to the acute exposure assessment that the EPA 
conducts as part of the risk review under section 112 of the CAA. The 
accuracy of an acute inhalation exposure assessment depends on the 
simultaneous occurrence of independent factors that may vary greatly, 
such as hourly emissions rates, meteorology, and the presence of humans 
at the location of the maximum concentration. In the acute screening 
assessment that we conduct under the RTR program, we assume that peak 
emissions from the source category and worst-case meteorological 
conditions co-occur, thus, resulting in maximum ambient concentrations. 
These two events are unlikely to occur at the same time, making these 
assumptions conservative. We then include the additional assumption 
that a person is located at this point during this same time period. 
For this source category, these assumptions would tend to be worst-case 
actual exposures, as it is unlikely that a person would be located at 
the point of maximum exposure during the time when peak emissions and 
worst-case meteorological conditions occur simultaneously.
f. Uncertainties in the Multipathway and Environmental Risk Screening 
Assessments
    For each source category, we generally rely on site-specific levels 
of PB-HAP or environmental HAP emissions to determine whether a refined 
assessment of the impacts from multipathway exposures is necessary or 
whether it is necessary to perform an environmental screening 
assessment. This determination is based on the results of a three-
tiered screening assessment that relies on the outputs from models--
TRIM.FaTE and AERMOD--that estimate environmental pollutant 
concentrations and human exposures for five PB-HAP (dioxins, POM, 
mercury, cadmium, and arsenic) and two acid gases (HF and HCl). For 
lead, we use AERMOD to determine ambient air concentrations, which are 
then compared to the secondary NAAQS standard for lead. Two important 
types of uncertainty associated with the use of these models in RTR 
risk assessments and inherent to any assessment that relies on 
environmental modeling are model uncertainty and input uncertainty.\26\
---------------------------------------------------------------------------

    \26\ In the context of this discussion, the term ``uncertainty'' 
as it pertains to exposure and risk encompasses both variability in 
the range of expected inputs and screening results due to existing 
spatial, temporal, and other factors, as well as uncertainty in 
being able to accurately estimate the true result.
---------------------------------------------------------------------------

    Model uncertainty concerns whether the model adequately represents 
the actual processes (e.g., movement and accumulation) that might occur 
in the environment. For example, does the model adequately describe the 
movement of a pollutant through the soil? This type of uncertainty is 
difficult to quantify. However, based on feedback received from 
previous EPA SAB reviews and other reviews, we are confident that the 
models used in the screening assessments are appropriate and state-of-
the-art for the multipathway and environmental screening risk 
assessments conducted in support of RTR.
    Input uncertainty is concerned with how accurately the models have 
been configured and parameterized for the assessment at hand. For Tier 
1 of the multipathway and environmental screening assessments, we 
configured the models to avoid underestimating exposure and risk. This 
was accomplished by selecting upper-end values from nationally 
representative datasets for the more influential parameters in the 
environmental model, including selection and spatial configuration of 
the area of interest, lake location and size, meteorology, surface 
water, soil characteristics, and structure of the aquatic food web. We 
also assume an ingestion exposure scenario and values for human 
exposure factors that represent reasonable maximum exposures.
    In Tier 2 of the multipathway and environmental screening 
assessments, we refine the model inputs to account

[[Page 20222]]

for meteorological patterns in the vicinity of the facility versus 
using upper-end national values, and we identify the actual location of 
lakes near the facility rather than the default lake location that we 
apply in Tier 1. By refining the screening approach in Tier 2 to 
account for local geographical and meteorological data, we decrease the 
likelihood that concentrations in environmental media are 
overestimated, thereby increasing the usefulness of the screening 
assessment. In Tier 3 of the screening assessments, we refine the model 
inputs again to account for hour-by-hour plume rise and the height of 
the mixing layer. We can also use those hour-by-hour meteorological 
data in a TRIM.FaTE run using the screening configuration corresponding 
to the lake location. These refinements produce a more accurate 
estimate of chemical concentrations in the media of interest, thereby 
reducing the uncertainty with those estimates. The assumptions and the 
associated uncertainties regarding the selected ingestion exposure 
scenario are the same for all three tiers.
    For the environmental screening assessment for acid gases, we 
employ a single-tiered approach. We use the modeled air concentrations 
and compare those with ecological benchmarks.
    For all tiers of the multipathway and environmental screening 
assessments, our approach to addressing model input uncertainty is 
generally cautious. We choose model inputs from the upper end of the 
range of possible values for the influential parameters used in the 
models, and we assume that the exposed individual exhibits ingestion 
behavior that would lead to a high total exposure. This approach 
reduces the likelihood of not identifying high risks for adverse 
impacts.
    Despite the uncertainties, when individual pollutants or facilities 
do not exceed screening threshold emission rates (i.e., screen out), we 
are confident that the potential for adverse multipathway impacts on 
human health is very low. On the other hand, when individual pollutants 
or facilities do exceed screening threshold emission rates, it does not 
mean that impacts are significant, only that we cannot rule out that 
possibility and that a refined assessment for the site might be 
necessary to obtain a more accurate risk characterization for the 
source category.
    The EPA evaluates the following HAP in the multipathway and/or 
environmental risk screening assessments, where applicable: Arsenic, 
cadmium, dioxins/furans, lead, mercury (both inorganic and methyl 
mercury), POM, HCl, and HF. These HAP represent pollutants that can 
cause adverse impacts either through direct exposure to HAP in the air 
or through exposure to HAP that are deposited from the air onto soils 
and surface waters and then through the environment into the food web. 
These HAP represent those HAP for which we can conduct a meaningful 
multipathway or environmental screening risk assessment. For other HAP 
not included in our screening assessments, the model has not been 
parameterized such that it can be used for that purpose. In some cases, 
depending on the HAP, we may not have appropriate multipathway models 
that allow us to predict the concentration of that pollutant. The EPA 
acknowledges that other HAP beyond these that we are evaluating may 
have the potential to cause adverse effects and, therefore, the EPA may 
evaluate other relevant HAP in the future, as modeling science and 
resources allow.

IV. Analytical Results and Proposed Decisions

A. What are the results of the risk assessment and analyses?

1. Inhalation Risk Assessment Results
    Table 2 of this preamble provides a summary of the results of the 
inhalation risk assessment for the source category. More detailed 
information on the risk assessment can be found in the risk document, 
available in the docket for this action.

                                          Table 2--Engine Test Cells/Stands Inhalation Risk Assessment Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                   Maximum individual      Population at increased   Annual cancer incidence       Maximum chronic           Maximum
                                    cancer risk (in 1      risk of cancer >=1-in-1      (cases per year)         noncancer TOSHI \3\     screening acute
                                      million) \2\                 million         ---------------------------------------------------- Noncancer HQ \4\
                               ----------------------------------------------------      Based on . . .            Based on . . .      -----------------
   Number of Facilities \1\          Based on . . .            Based on . . .      ----------------------------------------------------
                               ----------------------------------------------------
                                   Actual     Allowable      Actual     Allowable      Actual     Allowable      Actual     Allowable    Based on actual
                                 emissions    emissions    emissions    emissions    emissions    emissions    emissions    emissions    emissions level
                                   level        level        level        level        level        level        level        level
--------------------------------------------------------------------------------------------------------------------------------------------------------
59............................          20           70        2,700      190,000        0.005         0.02          0.1          0.5   HQREL = 9
                                                                                                                                         (acrolein).
                                                                                                                                        HQAEGL-1 = 0.4.
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Number of facilities evaluated in the risk analysis.
\2\ Maximum individual excess lifetime cancer risk due to HAP emissions from the source category.
\3\ Maximum TOSHI. The target organ system with the highest TOSHI for the source category is respiratory. The respiratory TOSHI was calculated using the
  CalEPA chronic REL for acrolein. The EPA is in the process of updating the IRIS RfC for acrolein. If the RfC is updated prior to signature of the
  final rule, we will use it in the assessment.
\4\ The maximum estimated acute exposure concentration was divided by available short-term threshold values to develop an array of HQ values. HQ values
  shown use the lowest available acute threshold value, which in most cases is the REL. When an HQ exceeds 1, we also show the HQ using the next lowest
  available acute dose-response value.

As shown in Table 2, the chronic inhalation cancer risk assessment, 
based on actual emissions could be as high as 20-in-1 million, with 
benzene, 1,3-butadiene, formaldehyde, and acetaldehyde emissions from 
reciprocating engine testing as the major contributors to the risk. The 
total estimated cancer incidence from this source category is 0.005 
excess cancer cases per year, or one excess case in every 200 years. 
About 2,700 people are estimated to have cancer risks above 1-in-1 
million from HAP emitted from this source category, with 60 of those 
people estimated to have cancer risks above 10-in-1 million. The 
maximum chronic noncancer HI value for the source category could be up 
to 0.1 (respiratory) driven by emissions of acrolein, acetaldehyde, 
formaldehyde, and naphthalene from reciprocating engine testing, and no 
one is exposed to TOSHI levels above 1.
    Results from the inhalation risk assessment using the MACT-
allowable emissions indicate that the cancer MIR could be as high as 
70-in-1 million with benzene, 1,3-butadiene, formaldehyde, and 
acetaldehyde emissions from

[[Page 20223]]

reciprocating engine testing driving the risks, and that the maximum 
chronic noncancer TOSHI (respiratory) value could be as high as 0.5 at 
the MACT-allowable emissions level with acrolein, acetaldehyde, 
formaldehyde, and naphthalene emissions from reciprocating engine 
testing driving the TOSHI. The total estimated cancer incidence from 
this source category considering allowable emissions is expected to be 
about 0.02 excess cancer cases per year or 1 excess case in every 50 
years. Based on allowable emission rates, approximately 190,000 people 
are estimated to have cancer risks above 1-in-1 million, with 500 of 
those people estimated to have cancer risks above 10-in-1 million. No 
people are estimated to have a noncancer HI above 1.
2. Acute Risk Results
    Table 2 of this preamble provides the worst-case acute HQ (based on 
the REL) of 9, driven by actual emissions of acrolein. To better 
characterize the potential health risks associated with estimated 
worst-case acute exposures to HAP, and in response to a key 
recommendation from the SAB's peer review of the EPA's RTR risk 
assessment methodologies, we examined a wider range of available acute 
health metrics than we do for our chronic risk assessments. This is in 
acknowledgement that there are generally more data gaps and 
uncertainties in acute reference values than there are in chronic 
reference values. By definition, the acute REL represents a health-
protective level of exposure, with effects not anticipated below those 
levels, even for repeated exposures. However, the level of exposure 
that would cause health effects is not specifically known. Therefore, 
when an REL is exceeded and an AEGL-1 or ERPG-1 level is available 
(i.e., levels at which mild, reversible effects are anticipated in the 
general public for a single exposure), we typically use them as an 
additional comparative measure, as they provide an upper bound for 
exposure levels above which exposed individuals could experience 
effects. As the exposure concentration increases above the acute REL, 
the potential for effects increases.
    The highest refined screening acute HQ value was 9 (based on the 
acute REL for acrolein). This value includes a refinement of 
determining the highest HQ value that is outside facility boundaries. 
In this case the highest value (9) occurs adjacent to the property 
boundary in a remote wooded location. HQ values at any nearby 
residential location are below 1. As noted previously, the highest HQ 
assumes that the primary source of the acrolein emissions from turbine 
engine testing operations was modeled with an hourly emissions 
multiplier of 9.5 times the annual emissions rate. As presented in 
Table 2, no facilities are estimated to have an HQ based on an AEGL or 
an EPRG greater than 1.
3. Multipathway Risk Screening Results
    Of the 59 facilities in the source category, 21 facilities reported 
emissions of carcinogenic PB-HAP (arsenic and POM), and 23 facilities 
reported emissions of non-carcinogenic PB-HAP (cadmium and mercury). Of 
the facilities included in the assessment, three facilities reported 
emissions of a carcinogenic PB-HAP (arsenic) that exceeded a Tier 1 
cancer screening threshold emission rate, and one facility reported 
emissions of non-carcinogenic PB-HAP (cadmium and mercury) that 
exceeded a Tier 1 noncancer screening threshold emission rate. For 
facilities that exceeded the Tier 1 multipathway screening threshold 
emission rate for one or more PB-HAP, we used additional facility site-
specific information to perform a Tier 2 assessment and determine the 
maximum chronic cancer and noncancer impacts for the source category. 
Based on the Tier 2 multipathway cancer assessment, the arsenic 
emissions exceeded the Tier 2 screening threshold emission rate by a 
factor of 2.
    An exceedance of a screening threshold emission rate in any of the 
tiers cannot be equated with a risk value or an HQ (or HI). Rather, it 
represents a high-end estimate of what the risk or hazard may be. For 
example, a screening threshold emission rate of 2 for a non-carcinogen 
can be interpreted to mean that we are confident that the HQ would be 
lower than 2. Similarly, a tier screening threshold emission rate of 30 
for a carcinogen means that we are confident that the risk is lower 
than 30-in-1 million. Our confidence comes from the conservative, or 
health-protective, assumptions encompassed in the screening tiers: We 
choose inputs from the upper end of the range of possible values for 
the influential parameters used in the screening tiers, and we assume 
that the exposed individual exhibits ingestion behavior that would lead 
to a high total exposure.
    The Tier 2 noncancer screening threshold emission rate for both 
mercury and cadmium emissions were below 1. Thus, based on the Tier 2 
results presented above, additional screening or site-specific 
assessments were not deemed necessary.
4. Environmental Risk Screening Results
    As described in section III.A of this document, we conducted an 
environmental risk screening assessment for the Engine Test Cells/
Stands source category for the following pollutants: Arsenic, cadmium, 
HCl, HF, lead, mercury (methyl mercury and mercuric chloride), and 
POMs.
    In the Tier 1 screening analysis for PB-HAP (other than lead, which 
was evaluated differently), arsenic and POM emissions had no 
exceedances of any of the ecological benchmarks evaluated. Divalent 
mercury, methyl mercury and cadmium emissions had Tier 1 exceedances at 
one facility of surface soil benchmarks by a maximum screening value of 
3.
    A Tier 2 screening analysis was performed for divalent mercury, 
methyl mercury, and cadmium emissions. In the Tier 2 screening 
analysis, there were no exceedances of any of the ecological benchmarks 
evaluated for any of the pollutants.
    For lead, we did not estimate any exceedances of the secondary lead 
NAAQS. For HCl and HF, the average modeled concentration around each 
facility (i.e., the average concentration of all off-site data points 
in the modeling domain) did not exceed any ecological benchmark. In 
addition, each individual modeled concentration of HCl and HF (i.e., 
each off-site data point in the modeling domain) was below the 
ecological benchmarks for all facilities.
    Based on the results of the environmental risk screening analysis, 
we do not expect an adverse environmental effect as a result of HAP 
emissions from this source category.
5. Facility-Wide Risk Results
    The facility-wide chronic MIR and TOSHI are based on emissions from 
all sources at the identified facilities (both MACT and non-MACT 
sources). The results of the facility-wide assessment for cancer risks 
indicate that 23 facilities have a facility-wide cancer MIR greater 
than or equal to 1-in-1 million, and 10 of those facilities have a 
facility-wide cancer MIR greater than or equal to 10-in-1-million. The 
maximum facility-wide cancer MIR is 70-in-1 million, mainly driven by 
emissions of chromium (VI) compounds from organic solvent 
(miscellaneous VOC) evaporation. The total estimated cancer incidence 
from the whole facility is 0.03 excess cancer cases per year, or about 
one excess case in every 33 years. Approximately 190,000 people are 
estimated to have cancer risks above 1-in-1 million from exposure to 
HAP emitted from both MACT and non-

[[Page 20224]]

MACT sources at the 59 facilities in this source category, with 6,800 
of those people estimated to have cancer risks above 10-in-1 million. 
The maximum facility-wide TOSHI (neurological) for the source category 
is estimated to be less than 1 (at 0.4), mainly driven by emissions of 
lead compounds and hydrogen cyanide from open burning of rocket 
propellant (an industrial solid waste disposal process) and by 
trichloroethylene emissions from liquid waste (a general waste 
treatment process). No people are exposed to noncancer HI levels above 
1, based on facility-wide emissions from the 59 facilities in this 
source category.
6. What demographic groups might benefit from this regulation?
    To examine the potential for any environmental justice issues that 
might be associated with the source category, we performed a 
demographic analysis, which is an assessment of risk to individual 
demographic groups of the populations living within 5 km and within 50 
km of the facilities. In the analysis, we evaluated the distribution of 
HAP-related cancer and noncancer risk from the Engine Test Cells/Stands 
source category across different demographic groups within the 
populations living near facilities.\27\
---------------------------------------------------------------------------

    \27\ Demographic groups included in the analysis are: White, 
African American, Native American, other races and multiracial, 
Hispanic or Latino, children 17 years of age and under, adults 18 to 
64 years of age, adults 65 years of age and over, adults without a 
high school diploma, people living below the poverty level, people 
living two times the poverty level, and linguistically isolated 
people.
---------------------------------------------------------------------------

    The results of the demographic analysis are summarized in Table 3 
below. These results, for various demographic groups, are based on the 
estimated risk from actual emissions levels for the population living 
within 50 km of the facilities.

                       Table 3--Engine Test Cells/Stands Demographic Risk Analysis Results
----------------------------------------------------------------------------------------------------------------
       Engine test cells/stands source category:  Demographic assessment results--50 km study area radius
-----------------------------------------------------------------------------------------------------------------
                                                                                    Population
                                                                                    with cancer
                                                                                   risk greater     Population
                                                                                   than or equal      with HI
                                                                                     to 1 in 1    greater than 1
                                                                                      million
----------------------------------------------------------------------------------------------------------------
                                                                    Nationwide            Source Category
----------------------------------------------------------------------------------------------------------------
Total Population................................................     317,746,049           2,745               0
----------------------------------------------------------------------------------------------------------------
                                                                           White and Minority by Percent
----------------------------------------------------------------------------------------------------------------
White...........................................................              62              90               0
Minority........................................................              38              10               0
----------------------------------------------------------------------------------------------------------------
                                                                                Minority by Percent
----------------------------------------------------------------------------------------------------------------
African American................................................              12               3               0
Native American.................................................             0.8             0.4               0
Hispanic or Latino (includes white and nonwhite)................              18               2               0
Other and Multiracial...........................................               7               4               0
----------------------------------------------------------------------------------------------------------------
                                                                                 Income by Percent
----------------------------------------------------------------------------------------------------------------
Below Poverty Level.............................................              14              13               0
Above Poverty Level.............................................              86              87               0
----------------------------------------------------------------------------------------------------------------
                                                                               Education by Percent
----------------------------------------------------------------------------------------------------------------
Over 25 and without a High School Diploma.......................              14               9               0
Over 25 and with a High School Diploma..........................              86              91               0
----------------------------------------------------------------------------------------------------------------
                                                                        Linguistically Isolated by Percent
----------------------------------------------------------------------------------------------------------------
Linguistically Isolated.........................................               6               2               0
----------------------------------------------------------------------------------------------------------------

    The results of the Engine Test Cells/Stands source category 
demographic analysis indicate that emissions from the source category 
expose approximately 2,700 people to a cancer risk at or above 1-in-1 
million and no people to a chronic noncancer TOSHI greater than 1. 
Regarding cancer risk, the specific demographic results indicate that 
the percentage of the population potentially impacted by engine test 
cells/stands emissions is greater than its corresponding nationwide 
percentage for the following demographics: Above Poverty Level (87 
percent for the source category compared to 86 percent nationwide), and 
Over 25 and with a High School Diploma (91 percent for the source 
category compared to 86 percent nationwide). The remaining demographic 
group percentages are the same or less than the corresponding 
nationwide percentages.
    The methodology and the results of the demographic analysis are 
presented in a technical report, Risk and Technology Review--Analysis 
of Demographic Factors for Populations Living Near Engine Test Cells/
Stands Source Category Operations, available in the docket for this 
action.

[[Page 20225]]

B. What are our proposed decisions regarding risk acceptability, ample 
margin of safety, and adverse environmental effect?

1. Risk Acceptability
    As noted in section III of this preamble, the EPA sets standards 
under CAA section 112(f)(2) using ``a two-step standard-setting 
approach, with an analytical first step to determine an `acceptable 
risk' that considers all health information, including risk estimation 
uncertainty, and includes a presumptive limit on MIR of approximately 
1-in-10 thousand'' (see 54 FR 38045, September 14, 1989). In this 
proposal, the EPA estimated risks based on actual and allowable 
emissions from engine test cells/stands located at major sources of 
HAP, and we considered these in determining acceptability.
    The estimated inhalation cancer risk to the individual most exposed 
to actual or allowable emissions from the source category is 70-in-1 
million. The estimated incidence of cancer due to inhalation exposures 
is 0.02 excess cancer cases per year, or one excess case every 50 
years. Approximately 190,000 people face an increased cancer risk at or 
above 1-in-1 million due to inhalation exposure to actual or allowable 
HAP emissions from this source category. The estimated maximum chronic 
noncancer TOSHI from inhalation exposure for this source category is 
0.5. The screening assessment of worst-case inhalation impacts 
indicates a worst-case maximum acute HQ of 9 for acrolein based on the 
1-hour REL and concentrations that are only 30 percent of the 1-hour 
AEGL-1 and ERPG-1.
    Potential multipathway human health risks were estimated using a 3-
tier screening assessment of the PB-HAP emitted by facilities in this 
source category. The only pollutant with elevated Tier 1 and Tier 2 
screening values was arsenic, which is a carcinogen. The Tier 2 
screening value for arsenic was 2. For noncancer, the Tier 2 screening 
values for all pollutants were less than 1.
    In determining whether risks are acceptable for this source 
category, the EPA considered all available health information and risk 
estimation uncertainty as described above. The risk results indicate 
that both the actual and allowable inhalation cancer risks to the 
individual most exposed are well below 100-in-1 million, which is the 
presumptive limit of acceptability. In addition, the highest chronic 
noncancer TOSHI is well below 1, indicating low likelihood of adverse 
noncancer effects from inhalation exposures. The maximum acute HQ for 
all pollutants is 9 based on the REL for acrolein. As discussed in 
section III.C.3.c of this preamble, exceeding the REL does not 
automatically indicate an adverse health impact. Because of the 
conservative nature of the acute inhalation screening assessment 
(concurrent maximum emissions from all emission points, worst-case 
meteorology, and an exposed person at the location of highest 
concentration for a full hour), there is low probability that the 
maximum HQ of 9 is associated with adverse health effects. Further, the 
highest 1-hour acrolein concentration is only 30 percent of the 1-hour 
AEGL-1 and ERPG-1. There are also low risks associated with ingestion 
via multipathway exposure, with the highest cancer risk being 2-in-1 
million and the highest noncancer HI being less than 1, based on a Tier 
2 multipathway assessment.
    Considering all the health risk information and factors discussed 
above, including the uncertainties discussed in section III of this 
preamble, the EPA proposes that the risks are acceptable for this 
source category.
2. Ample Margin of Safety Analysis
    As directed by CAA section 112(f)(2), we conducted an analysis to 
determine whether the current emissions standards provide an ample 
margin of safety to protect public health. Under the ample margin of 
safety analysis, the EPA considers all health factors evaluated in the 
risk assessment and evaluates the cost and feasibility of available 
control technologies and other measures (including the controls, 
measures, and costs reviewed under the technology review) that could be 
applied to this source category to further reduce the risks (or 
potential risks) due to emissions of HAP identified in our risk 
assessment. In this analysis, we considered the results of the 
technology review, risk assessment, and other aspects of our MACT rule 
review to determine whether there are any emission reduction measures 
necessary to provide an ample margin of safety with respect to the 
risks associated with these emissions.
    Our risk analysis indicated the risks from the source category are 
low for both cancer and noncancer health effects, and, therefore, any 
risk reductions from further available control options would result in 
minimal health benefits. Moreover, as noted in our discussion of the 
technology review in section IV.C of this preamble, no additional cost-
effective measures were identified for reducing HAP emissions from 
affected sources in the Engine Test Cells/Stands source category. Thus, 
we are proposing that the current Engine Test Cells/Stands NESHAP 
provides an ample margin of safety to protect public health.
3. Adverse Environmental Effect
    Based on the results of our environmental risk screening 
assessment, we conclude that there is not an adverse environmental 
effect from the Engine Test Cells/Stands source category. We are 
proposing that it is not necessary to set a more stringent standard to 
prevent, taking into consideration costs, energy, safety, and other 
relevant factors, an adverse environmental effect.

C. What are the results and proposed decisions based on our technology 
review?

1. How did we evaluate technological developments?
    Section 112(d)(6) of the CAA requires a review of ``developments in 
practices, processes and control technologies'' in each source category 
as part of the technology review process. For this technology review, 
the ``developments'' we consider include:
     Add-on control technology that was not identified during 
the current NESHAP development;
     Improvement to an existing add-on control technology 
resulting in significant additional HAP emissions reductions;
     Work practice or operational procedure that was not 
previously identified during the current NESHAP development; or
     Process change or pollution prevention alternative that 
was not identified and considered during the current NESHAP 
development.
    Developments in practices, processes, and control technologies were 
investigated through discussions with industry representatives, reviews 
of available construction and operating permits, searches of the EPA's 
RBLC, site visits, and literature searches. We also included questions 
on developments in practices, processes, and control technology in this 
source category in the 2016 questionnaire that was completed by 10 
companies. The questionnaire, along with the responses received, are 
included in the docket.
2. What was our analysis and what are our conclusions regarding 
technological developments?
    Our review of the practices, processes, and control technology for 
the Engine Test Cells/Stands source category did

[[Page 20226]]

not reveal any development that would result in revisions to the 
emission standards. In the original NESHAP, the technology basis for 
the MACT standard was the use of add-on capture systems and control 
devices (i.e., thermal oxidizers or catalytic oxidizers). Our review 
did not identify any new or improved add-on control technology, any new 
work practices, operational procedures, process changes, or new 
pollution prevention approaches that reduce emissions in the category 
that have been implemented at engine testing operations since 
promulgation of the current NESHAP. Consequently, we propose that no 
revisions to the NESHAP are necessary pursuant to CAA section 
112(d)(6). For a detailed discussion of the findings, refer to the 
Technology Review for the Engine Test Cells/Stands Source Category 
memorandum in the docket.

D. What other actions are we proposing?

    In addition to the proposed actions described above, we are 
proposing additional revisions to the NESHAP. We are proposing 
revisions to the SSM provisions of the MACT rule in order to ensure 
that they are consistent with the Court decision in Sierra Club v. EPA, 
551 F. 3d 1019 (D.C. Cir. 2008), which vacated two provisions that 
exempted sources from the requirement to comply with otherwise 
applicable CAA section 112(d) emission standards during periods of SSM. 
We also are proposing to require electronic submittal of notifications, 
semiannual reports, and compliance reports (which include performance 
test reports). Our analyses and proposed changes related to these 
issues are discussed below.
1. SSM
    In its 2008 decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008), the Court vacated portions of two provisions in the EPA's 
CAA section 112 regulations governing the emissions of HAP during 
periods of SSM. Specifically, the Court vacated the SSM exemption 
contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that 
under section 302(k) of the CAA, emissions standards or limitations 
must be continuous in nature and that the SSM exemption violates the 
CAA's requirement that some CAA section 112 standards apply 
continuously.
    We are proposing the elimination of the SSM exemption in this rule, 
which appears at 40 CFR 63.9305, 40 CFR 63.9340, and in Table 7 to 
subpart PPPPP of 40 CFR part 63. Consistent with Sierra Club v. EPA, we 
are proposing standards in this rule that apply at all times. We are 
also proposing several revisions to Table 7 (the General Provisions 
Applicability Table) as is explained in more detail below. For example, 
we are proposing to eliminate the incorporation of the General 
Provisions' requirement that the source develop an SSM plan. We also 
are proposing to eliminate and revise certain recordkeeping and 
reporting requirements related to the SSM exemption as further 
described below.
    The EPA has attempted to ensure that the provisions we are 
proposing to eliminate are inappropriate, unnecessary, or redundant in 
the absence of the SSM exemption. We are specifically seeking comment 
on whether we have successfully done so. The EPA believes the removal 
of the SSM exemption creates no additional burden to facilities 
regulated under the Engine Test Cells/Stands NESHAP. Deviations 
currently addressed by a facility's SSM plan are required to be 
reported in the Semiannual Compliance Report, a requirement that 
remains under the proposal (40 CFR 63.9350). Facilities will no longer 
need to develop an SSM plan or keep it current (Table 7, 40 CFR part 
63, subpart PPPPP). We are specifically seeking comment on whether we 
have successfully removed the SSM exemption.
    In proposing the standards in this rule, the EPA has taken into 
account startup and shutdown periods and, for the reasons explained 
below, is not proposing alternate standards for those periods. For add-
on control systems, the Engine Test Cells/Stands NESHAP requires the 
measurement of thermal oxidizer operating temperature or catalytic 
oxidizer average temperature across the catalyst bed as well as the 
measurement of the emission capture system volumetric flow rate or 
facial velocity. Operating limits apply at all times (40 CFR 63.9302), 
including during periods of startup and shutdown. The Engine Test 
Cells/Stands NESHAP requires thermal oxidizer or catalytic oxidizer 
operating temperature and other add-on control device operating 
parameters to be recorded at least once every 15 minutes. The Engine 
Test Cells/Stands NESHAP specifies in 40 CFR 63.9340(b) that if an 
operating parameter is out of the allowed range, this is a deviation 
from the operating limit and must be reported as specified in 40 CFR 
63.9350(d). Review of permits of facilities using add-on controls 
indicated that they were required by permit to operate the add-on 
controls at all times the engine test cells are being operated.
    In proposing these rule amendments, the EPA has taken into account 
startup and shutdown periods and, for the reasons explained below, has 
not proposed alternate standards for those periods. Startups and 
shutdowns are part of normal operations for the Engine Test Cells/
Stands source category. As currently specified in 40 CFR 63.9302(a), 
any new or reconstructed affected source for which you use add-on 
control option must meet operating limits ``at all times.'' This means 
that during startup and shutdown periods, in order for a facility using 
add-on controls to meet the emission and operating standards, the 
control device for an engine test cell/stand facility needs to be 
turned on and operating at specified levels before the facility begins 
engine testing operations, and the control equipment needs to continue 
to be operated until after the facility ceases engine testing 
operations.
    Periods of startup, normal operations, and shutdown are all 
predictable and routine aspects of a source's operations. Malfunctions, 
in contrast, are neither predictable nor routine. Instead they are, by 
definition, sudden, infrequent, and not reasonably preventable failures 
of emissions control, process, or monitoring equipment. (40 CFR 63.2, 
definition of malfunction). The EPA interprets CAA section 112 as not 
requiring emissions that occur during periods of malfunction to be 
factored into development of CAA section 112 standards and this reading 
has been upheld as reasonable by the Court in U.S. Sugar Corp. v. EPA, 
830 F.3d 579, 606-610 (2016). Under CAA section 112, emissions 
standards for new sources must be no less stringent than the level 
``achieved'' by the best controlled similar source and for existing 
sources generally must be no less stringent than the average emission 
limitation ``achieved'' by the best performing 12 percent of sources in 
the category. There is nothing in CAA section 112 that directs the 
Agency to consider malfunctions in determining the level ``achieved'' 
by the best performing sources when setting emission standards. As the 
Court has recognized, the phrase ``average emissions limitation 
achieved by the best performing 12 percent of'' sources ``says nothing 
about how the performance of the best units is to be calculated.'' 
National Association of Clean Water Agencies v. EPA, 734 F.3d 1115, 
1141 (D.C. Cir. 2013). While the EPA accounts for variability in 
setting emissions standards, nothing in CAA section 112 requires the 
Agency to consider malfunctions as part of that analysis. The EPA is 
not required to treat a malfunction in the same manner as the type of 
variation in performance

[[Page 20227]]

that occurs during routine operations of a source. A malfunction is a 
failure of the source to perform in ``normal or usual manner'' and no 
statutory language compels the EPA to consider such events in setting 
CAA section 112 standards.
    As the Court recognized in U.S. Sugar Corp., accounting for 
malfunctions in setting standards would be difficult, if not 
impossible, given the myriad different types of malfunctions that can 
occur across all sources in the category and given the difficulties 
associated with predicting or accounting for the frequency, degree, and 
duration of various malfunctions that might occur. Id. at 608 (``the 
EPA would have to conceive of a standard that could apply equally to 
the wide range of possible boiler malfunctions, ranging from an 
explosion to minor mechanical defects. Any possible standard is likely 
to be hopelessly generic to govern such a wide array of 
circumstances.'') As such, the performance of units that are 
malfunctioning is not ``reasonably'' foreseeable. See, for example, 
Sierra Club v. EPA, 167 F.3d 658, 662 (D.C. Cir. 1999). ``The EPA 
typically has wide latitude in determining the extent of data gathering 
necessary to solve a problem. We generally defer to an agency's 
decision to proceed on the basis of imperfect scientific information, 
rather than to `invest the resources to conduct the perfect study.'' 
See also, Weyerhaeuser v. Costle, 590 F.2d 1011, 1058 (D.C. Cir. 1978), 
``In the nature of things, no general limit, individual permit, or even 
any upset provision can anticipate all upset situations. After a 
certain point, the transgression of regulatory limits caused by 
`uncontrollable acts of third parties,' such as strikes, sabotage, 
operator intoxication or insanity, and a variety of other 
eventualities, must be a matter for the administrative exercise of 
case-by-case enforcement discretion, not for specification in advance 
by regulation.'' In addition, emissions during a malfunction event can 
be significantly higher than emissions at any other time of source 
operation. For example, if an air pollution control device with 99-
percent removal goes offline as a result of a malfunction (as might 
happen if, for example, the bags in a baghouse catch fire) and the 
emission unit is a steady state type unit that would take days to shut 
down, the source would go from 99-percent control to zero control until 
the control device was repaired. The source's emissions during the 
malfunction would be 100 times higher than during normal operations. As 
such, the emissions over a 4-day malfunction period would exceed the 
annual emissions of the source during normal operations. As this 
example illustrates, accounting for malfunctions could lead to 
standards that are not reflective of (and significantly less stringent 
than) levels that are achieved by a well-performing non-malfunctioning 
source. It is reasonable to interpret CAA section 112 to avoid such a 
result. The EPA's approach to malfunctions is consistent with CAA 
section 112 and is a reasonable interpretation of the statute.
    Although no statutory language compels the EPA to set standards for 
malfunctions, the EPA has the discretion to do so where feasible. For 
example, in the Petroleum Refinery Sector RTR, the EPA established a 
work practice standard for unique types of malfunction that result in 
releases from pressure relief devices or emergency flaring events 
because information was available to determine that such work practices 
reflected the level of control that applies to the best performers (80 
FR 75178, 75211-14; December 1, 2015). The EPA will consider whether 
circumstances warrant setting standards for a particular type of 
malfunction and, if so, whether the EPA has sufficient information to 
identify the relevant best performing sources and establish a standard 
for such malfunctions. We also encourage commenters to provide any such 
information.
    In the event that a source fails to comply with the applicable CAA 
section 112(d) standards as a result of a malfunction event, the EPA 
would determine an appropriate response based on, among other things, 
the good faith efforts of the source to minimize emissions during 
malfunction periods, including preventative and corrective actions, as 
well as root cause analyses to ascertain and rectify excess emissions. 
The EPA would also consider whether the source's failure to comply with 
the CAA section 112(d) standard was, in fact, sudden, infrequent, not 
reasonably preventable, and was not instead caused in part by poor 
maintenance or careless operation. 40 CFR 63.2 (definition of 
malfunction).
    If the EPA determines in a particular case that an enforcement 
action against a source for violation of an emission standard is 
warranted, the source can raise any and all defenses in that 
enforcement action and the federal district court will determine what, 
if any, relief is appropriate. The same is true for citizen enforcement 
actions. Similarly, the presiding officer in an administrative 
proceeding can consider any defense raised and determine whether 
administrative penalties are appropriate.
    In summary, the EPA interpretation of the CAA and, in particular, 
CAA section 112 is reasonable and encourages practices that will avoid 
malfunctions. Administrative and judicial procedures for addressing 
exceedances of the standards fully recognize that violations may occur 
despite good faith efforts to comply and can accommodate those 
situations. U.S. Sugar Corporation v. EPA (830 F.3d 579, 606-610; D.C. 
Cir. 2016).
a. General Duty
    We are proposing to revise the General Provisions table (Table 7) 
entry for 40 CFR 63.6(e)(1)-(2) by redesignating it as 40 CFR 
63.6(e)(1)(i) and changing the ``yes'' in column 3 to a ``no.'' Section 
63.6(e)(1)(i) describes the general duty to minimize emissions. Some of 
the language in that section is no longer necessary or appropriate in 
light of the elimination of the SSM exemption. We are proposing instead 
to add general duty regulatory text at 40 CFR 63.9305 that reflects the 
general duty to minimize emissions while eliminating the reference to 
periods covered by an SSM exemption. The current language in 40 CFR 
63.6(e)(1)(i) characterizes what the general duty entails during 
periods of SSM. With the elimination of the SSM exemption, there is no 
need to differentiate between normal operations and SSM events in 
describing the general duty. Therefore, the language the EPA is 
proposing for 40 CFR 63.9305 does not include that language from 40 CFR 
63.6(e)(1).
    We are also proposing to revise Table 7 to add an entry for 40 CFR 
63.6(e)(1)(ii) and include a ``no'' in column 3. Section 63.6(e)(1)(ii) 
imposes requirements that are not necessary with the elimination of the 
SSM exemption or are redundant with the general duty requirement being 
added at 40 CFR 63.9305.
    We are also proposing to revise Table 7 to add an entry for 40 CFR 
63.6(e)(1)(iii) and include a ``yes'' in column 3.
    Finally, we are proposing to revise Table 7 to remove an entry for 
40 CFR 63.6(e)(2) because this paragraph is reserved and is not 
applicable to 40 CFR part 63, subpart PPPPP.
b. SSM Plan
    We are proposing to revise Table 7 to add an entry for 40 CFR 
63.6(e)(3) and include a ``no'' in column 3. Generally, these 
paragraphs require development of an SSM plan and specify SSM 
recordkeeping and reporting requirements related to the SSM plan. As 
noted, the EPA is proposing to remove the SSM exemptions. Therefore,

[[Page 20228]]

affected units will be subject to an emission standard during such 
events. The applicability of a standard during such events will ensure 
that sources have ample incentive to plan for and achieve compliance 
and, thus, the SSM plan requirements are no longer necessary.
c. Compliance With Standards
    We are proposing to revise Table 7 entry for 40 CFR 63.6(f)(1) by 
changing the ``yes'' in column 3 to a ``no.'' The current language of 
40 CFR 63.6(f)(1) exempts sources from non-opacity standards during 
periods of SSM. As discussed above, the Court in Sierra Club vacated 
the exemptions contained in this provision and held that the CAA 
requires that some CAA section 112 standards apply continuously. 
Consistent with Sierra Club, the EPA is proposing to revise standards 
in this rule to apply at all times.
d. Performance Testing
    We are proposing to revise Table 7 entry for 40 CFR 63.7(e)(1) by 
changing the ``yes'' in column 3 to a ``no.'' Section 63.7(e)(1) 
describes performance testing requirements. The EPA is instead 
proposing to revise the performance testing requirement at 40 CFR 
63.9321 to remove the language ``according to the requirements in Sec.  
63.7(e)(1)'' because 40 CFR 63.7(e)(1) restated the SSM exemption. 40 
CFR 63.9321(a) of the current rule specifies that performance testing 
must be conducted when the emission capture system and add-on control 
device are operating at a representative flow rate, and the add-on 
control device is operating at a representative inlet concentration. 
Section 63.9321(a) also specifies that the performance test be 
conducted under representative operating conditions for the engine test 
cell/stand. Operations during periods of SSM, and during periods of 
nonoperation do not constitute representative operating conditions. The 
EPA is proposing to add language that requires the owner or operator to 
record the process information that is necessary to document operating 
conditions during the test and include in such record an explanation to 
support that such conditions represent normal operation. Section 
63.7(e) requires that the owner or operator make available to the 
Administrator such records ``as may be necessary to determine the 
condition of the performance test'' available to the Administrator upon 
request but does not specifically require the information to be 
recorded. The regulatory text in the current rule already makes 
explicit the requirement to record the information.
e. Monitoring
    We are proposing to revise Table 7 entries for 40 CFR 63.8(c)(1)(i) 
and 40 CFR 63.8(c)(1)(iii) by changing the ``yes'' in column 3 to a 
``no.'' The cross-references to the general duty and SSM plan 
requirements in those subparagraphs are not necessary considering other 
requirements of 40 CFR 63.8 that require good air pollution control 
practices (40 CFR 63.8(c)(1)) and that set out the requirements of a 
quality control program for monitoring equipment (40 CFR 63.8(d)).
f. Recordkeeping
    We are proposing to revise the Table 7 entry for 40 CFR 
63.10(b)(2)(i) by changing the ``yes'' in column 3 to a ``no.'' Section 
63.10(b)(2)(i) describes the recordkeeping requirements during startup 
and shutdown. These recording provisions are no longer necessary 
because the EPA is proposing that recordkeeping and reporting 
applicable to normal operations will apply to startup and shutdown. In 
the absence of special provisions applicable to startup and shutdown, 
such as a startup and shutdown plan, there is no reason to retain 
additional recordkeeping for startup and shutdown periods.
    We are proposing to revise the Table 7 entry for 40 CFR 
63.10(b)(2)(ii) by changing the ``yes'' in column 3 to a ``no.'' 
Section 63.10(b)(2)(ii) describes the recordkeeping requirements during 
a malfunction. A similar record is already required in 40 CFR 
63.9350(c). The regulatory text in 40 CFR 63.9350(c) differs from the 
General Provisions in that the General Provisions requires the creation 
and retention of a record of the occurrence and duration of each 
malfunction of process, air pollution control, and monitoring 
equipment; whereas 40 CFR 63.9350(c) applies to any failure to meet an 
applicable standard and is requiring that the source record the date, 
time, and duration of the failure rather than the ``occurrence.'' The 
EPA is also proposing to add to 40 CFR 63.9350(c) a requirement that 
sources keep records that include a list of the affected source or 
equipment and actions taken to minimize emissions, an estimate of the 
quantity of each regulated pollutant emitted over the standard for 
which the source failed to meet the standard, and a description of the 
method used to estimate the emissions. Examples of such methods would 
include product-loss calculations, mass balance calculations, 
measurements when available, or engineering judgment based on known 
process parameters. The EPA is proposing to require that sources keep 
records of this information to ensure that there is adequate 
information to allow the EPA to determine the severity of any failure 
to meet a standard, and to provide data that may document how the 
source met the general duty to minimize emissions when the source has 
failed to meet an applicable standard.
    We are proposing to revise the Table 7 by adding an entry for 40 
CFR 63.10(b)(2)(iv) and including a ``no'' in column 3. When 
applicable, the provision requires sources to record actions taken 
during SSM events when actions were inconsistent with their SSM plan. 
The requirement is no longer appropriate because SSM plans will no 
longer be required. The requirement previously applicable under 40 CFR 
63.10(b)(2)(iv)(B) to record actions to minimize emissions and record 
corrective actions is now applicable by reference to 40 CFR 63.9355(a).
    We are proposing to revise Table 7 by adding an entry for 40 CFR 
63.10(b)(2)(v) and including a ``no'' in column 3. When applicable, the 
provision requires sources to record actions taken during SSM events to 
show that actions taken were consistent with their SSM plan. The 
requirement is no longer appropriate because SSM plans will no longer 
be required.
    We are proposing to revise Table 7 entry for 40 CFR 63.10(c)(1)-
(6), (9)-(15) by re-designating it as 40 CFR 63.10(c)(1)-(6), (9)-(14) 
and adding an entry for 40 CFR 63.10(c)(15) and including a ``no'' in 
column 3. The EPA is proposing that 40 CFR 63.10(c)(15) no longer 
apply. When applicable, the provision allows an owner or operator to 
use the affected source's SSM plan or records kept to satisfy the 
recordkeeping requirements of the SSM plan, specified in 40 CFR 
63.6(e), to also satisfy the requirements of 40 CFR 63.10(c)(10) 
through (12). The EPA is proposing to eliminate this requirement 
because SSM plans would no longer be required, and, therefore, 40 CFR 
63.10(c)(15) no longer serves any useful purpose for affected units.
g. Reporting
    We are proposing to revise Table 7 entry for 40 CFR 63.10(d)(5) by 
changing the ``yes'' in column 3 to a ``no.'' Section 63.10(d)(5) 
describes the reporting requirements for startups, shutdowns, and 
malfunctions. To replace the General Provisions reporting requirement, 
the EPA is proposing to add reporting requirements to 40 CFR 63.9350. 
The replacement language differs from the General Provisions

[[Page 20229]]

requirement in that it eliminates periodic SSM reports as a stand-alone 
report. We are proposing language that requires sources that fail to 
meet an applicable standard at any time to report the information 
concerning such events in the semi-annual compliance report already 
required under this rule. We are proposing that the report must also 
contain the number, date, time, duration, and the cause of such events 
(including unknown cause, if applicable), a list of the affected source 
or equipment, an estimate of the quantity of each regulated pollutant 
emitted over any emission limit, and a description of the method used 
to estimate the emissions.
    Examples of such methods would include product-loss calculations, 
mass balance calculations, measurements when available, or engineering 
judgment based on known process parameters. The EPA is proposing this 
requirement to ensure that there is adequate information to determine 
compliance, to allow the EPA to determine the severity of the failure 
to meet an applicable standard, and to provide data that may document 
how the source met the general duty to minimize emissions during a 
failure to meet an applicable standard.
    We will no longer require owners or operators to determine whether 
actions taken to correct a malfunction are consistent with an SSM plan, 
because plans would no longer be required. The proposed amendments, 
therefore, eliminate the cross-reference to 40 CFR 63.10(d)(5)(i) that 
contains the description of the previously required SSM report format 
and submittal schedule from this section. These specifications are no 
longer necessary because the events will be reported in otherwise 
required reports with similar format and submittal requirements. 
Section 63.10(d)(5)(ii) describes an immediate report for startups, 
shutdowns, and malfunctions when a source failed to meet an applicable 
standard but did not follow the SSM plan. We will no longer require 
owners and operators to report when actions taken during a startup, 
shutdown, or malfunction were not consistent with an SSM plan because 
plans would no longer be required.
2. Electronic Reporting Requirements
    Through this proposal, the EPA is proposing that owners and 
operators of engine test cells/stands submit electronic copies of 
required performance test reports, performance evaluation reports, and 
semiannual compliance reports through the EPA's Central Data Exchange 
(CDX) using the Compliance and Emissions Data Reporting Interface 
(CEDRI). A description of the electronic data submission process is 
provided in the memorandum, Electronic Reporting Requirements for New 
Source Performance Standards (NSPS) and National Emission Standards for 
Hazardous Air Pollutants (NESHAP) Rules, available in Docket ID No. 
EPA-HQ-OAR-2018-0753. The proposed rule requires that performance test 
results collected using test methods that are supported by the EPA's 
Electronic Reporting Tool (ERT) as listed on the ERT website \28\ at 
the time of the test be submitted in the format generated through the 
use of the ERT and that other performance test results be submitted in 
portable document format (PDF) using the attachment module of the ERT. 
Similarly, performance evaluation results of continuous monitoring 
systems (CMS) measuring relative accuracy test audit (RATA) pollutants 
that are supported by the ERT at the time of the test must be submitted 
in the format generated through the use of the ERT and other 
performance evaluation results be submitted in PDF using the attachment 
module of the ERT.
---------------------------------------------------------------------------

    \28\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    For the semiannual compliance reports the proposed rule requires 
that owners and operators use the appropriate spreadsheet template to 
submit information to CEDRI. A draft version of the proposed template 
for these reports is included in the docket for this rulemaking.\29\ 
The EPA specifically requests comment on the content, layout, and 
overall design of the template.
---------------------------------------------------------------------------

    \29\ See 
Engine_Test_Cells_Semiannual_Spreadsheet_Template_Draft, available 
at Docket ID No. EPA-HQ-OAR-2018-0753.
---------------------------------------------------------------------------

    Additionally, the EPA has identified two broad circumstances in 
which electronic reporting extensions may be provided. In both 
circumstances, the decision to accept the claim of needing additional 
time to report is within the discretion of the Administrator, and 
reporting should occur as soon as possible. The EPA is providing these 
potential extensions to protect owners and operators from noncompliance 
in cases where they cannot successfully submit a report by the 
reporting deadline for reasons beyond their control. The situation 
where an extension may be warranted due to outages of either the EPA's 
CDX or CEDRI which precludes an owner or operator from accessing the 
system and submitting required reports is addressed in proposed 40 CFR 
63.9350(i). The situation where an extension may be warranted due to a 
force majeure event, which 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 an owner or operator from complying with the 
requirement to submit a report electronically as required by this rule 
is addressed in proposed 40 CFR 63.9350(j). Examples of such events are 
acts of nature, acts of war or terrorism, or equipment failure or 
safety hazards beyond the control of the facility.
    The electronic submittal of the reports addressed in this proposed 
rulemaking, when finalized, will increase the usefulness of the data 
contained in those reports, is in keeping with current trends in data 
availability and transparency, will further assist in the protection of 
public health and the environment, will improve compliance by 
facilitating the ability of regulated facilities to demonstrate 
compliance with requirements and by facilitating the ability of 
delegated state, local, tribal, and territorial air agencies and the 
EPA to assess and determine compliance, and will ultimately reduce 
burden on regulated facilities, delegated air agencies, and the EPA. 
Electronic reporting also eliminates paper-based, manual processes, 
thereby saving time and resources, simplifying data entry, eliminating 
redundancies, minimizing data reporting errors, and providing data 
quickly and accurately to the affected facilities, air agencies, the 
EPA, and the public. Moreover, electronic reporting is consistent with 
the EPA's plan \30\ to implement Executive Order 13563 and is in 
keeping with the EPA's Agency-wide policy \31\ developed in response to 
the White House's Digital Government Strategy.\32\ For more information 
on the benefits of electronic reporting, see the memorandum, Electronic 
Reporting Requirements for New Source Performance Standards (NSPS) and 
National Emission Standards for Hazardous Air Pollutants (NESHAP)

[[Page 20230]]

Rules, available in Docket ID No. EPA-HQ-OAR-2018-0753.
---------------------------------------------------------------------------

    \30\ EPA's Final Plan for Periodic Retrospective Reviews, August 
2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \31\ E-Reporting Policy Statement for EPA Regulations, September 
2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \32\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

3. Technical and Editorial Changes
    The following are additional proposed changes that address 
technical and editorial correction:
     Revising the monitoring requirements in 40 CFR 63.9307 to 
add THC as a continuous emission monitoring option and to add 
Performance Specification 8A and EPA Method 25A;
     Revising the initial compliance requirements in 40 CFR 
63.9320 to include a provision for the performance test to be used to 
demonstrate compliance;
     Revising Tables 3 and 4 to 40 CFR part 63, subpart PPPPP, 
to add alternative compliance option; and
     Revising section 40 CFR 63.9350 to address the reporting 
of performance tests and performance evaluations.

E. What compliance dates are we proposing?

    The EPA is proposing that existing affected sources must comply 
with the amendments in this rulemaking no later than 180 days after the 
effective date of the final rule. The EPA is also proposing that 
affected sources that commence construction or reconstruction after May 
8, 2019 must comply with all requirements of the subpart, including the 
amendments being proposed, no later than the effective date of the 
final rule or upon startup, whichever is later. All affected existing 
facilities would have to continue to meet the current requirements of 
40 CFR part 63, subpart PPPPP, until the applicable compliance date of 
the amended rule. The final action is not expected to be a ``major 
rule'' as defined by 5 U.S.C. 804(2), therefore, the effective date of 
the final rule will be the promulgation date as specified in CAA 
section 112(d)(10). For existing affected sources, we are proposing two 
changes that would impact ongoing compliance requirements for 40 CFR 
part 63, subpart PPPPP. As discussed elsewhere in this preamble, we are 
proposing to add a requirement that notifications, performance test 
results, and the semiannual reports using the new template be submitted 
electronically. We are also proposing to change the requirements for 
SSM by removing the exemption from the requirements to meet the 
standard during SSM periods and by removing the requirement to develop 
and implement an SSM plan. Our experience with similar industries that 
have been required to convert reporting mechanisms, install necessary 
hardware, install necessary software, become familiar with the process 
of submitting performance test results electronically through the EPA's 
CEDRI, test these new electronic submission capabilities, reliably 
employ electronic reporting, and convert logistics of reporting 
processes to different time-reporting parameters, shows that a time 
period of a minimum of 90 days, and more typically 180 days, is 
generally necessary to successfully complete these changes. Our 
experience with similar industries further shows that this sort of 
regulated facility generally requires a time period of 180 days to read 
and understand the amended rule requirements; evaluate their operations 
to ensure that they can meet the standards during periods of startup 
and shutdown as defined in the rule and make any necessary adjustments; 
adjust parameter monitoring and recording systems to accommodate 
revisions; and update their operations to reflect the revised 
requirements. The EPA recognizes the confusion that multiple different 
compliance dates for individual requirements would create and the 
additional burden such an assortment of dates would impose. From our 
assessment of the timeframe needed for compliance with the entirety of 
the revised requirements, the EPA considers a period of 180 days to be 
the most expeditious compliance period practicable, and, thus, is 
proposing that existing affected sources be in compliance with all of 
this regulation's revised requirements within 180 days of the 
regulation's effective date. We solicit comment on this proposed 
compliance period, and we specifically request submission of 
information from sources in this source category regarding specific 
actions that would need to be undertaken to comply with the proposed 
amended requirements and the time needed to make the adjustments for 
compliance with any of the revised requirements. We note that 
information provided may result in changes to the proposed compliance 
date.

V. Summary of Cost, Environmental, and Economic Impacts

A. What are the affected sources?

    There are currently 59 engine test cells/stands facilities 
operating in the United States that conduct engine testing operations 
and are subject to the Engine Test Cells/Stands NESHAP. The 40 CFR part 
63, subpart PPPPP, affected source is the collection of all equipment 
and activities associated with engine test cells/stands used for 
testing uninstalled stationary or uninstalled mobile engines located at 
a major source of HAP emissions. A new or reconstructed affected source 
is a completely new engine testing source that commenced construction 
after May 14, 2002, or meets the definition of reconstruction and 
commenced reconstruction after May 14, 2002.

B. What are the air quality impacts?

    At the current level of control, emissions of total HAP are 
estimated to be approximately 163 tpy. This represents a reduction in 
HAP emissions of about 80 tpy due to the current (2003) Engine Test 
Cells/Stands NESHAP. The proposed amendments will require all affected 
sources subject to the emission standards in the Engine Test Cells/
Stands NESHAP to operate without the SSM exemption. We do not expect 
that eliminating the SSM exemption will result in reduced emissions 
since the NESHAP requires that the operating limits established during 
the performance test for demonstrating continuous compliance must be 
met at all times.
    Indirect or secondary air emissions impacts are impacts that would 
result from the increased electricity usage associated with the 
operation of control devices (i.e., increased secondary emissions of 
criteria pollutants from power plants). Energy impacts consist of the 
electricity and steam needed to operate control devices and other 
equipment that would be required under this proposed rule. The EPA 
expects no secondary air emissions impacts or energy impacts from this 
rulemaking.

C. What are the cost impacts?

    We estimate that each facility in the source category will 
experience costs as a result of these proposed amendments that are 
estimated as part of the reporting and recordkeeping costs. Each 
facility will experience costs to read and understand the rule 
amendments. Costs associated with the elimination of the SSM exemption 
were estimated as part of the reporting and recordkeeping costs and 
include time for re-evaluating previously developed SSM record systems. 
Costs associated with the requirement to electronically submit 
notifications and semi-annual compliance reports using CEDRI were 
estimated as part of the reporting and recordkeeping costs and include 
time for becoming familiar with CEDRI and the reporting template for 
semi-annual compliance reports. The recordkeeping and reporting costs 
are presented in section VIII.C of this preamble.

[[Page 20231]]

D. What are the economic impacts?

    Economic impact analyses focus on changes in market prices and 
output levels. If changes in market prices and output levels in the 
primary markets are significant enough, impacts on other markets may 
also be examined. Both the magnitude of costs associated with the 
proposed requirements and the distribution of these costs among 
affected facilities can have a role in determining how the market will 
change in response to a proposed rule.
    Based on the costs associated with the elimination of the SSM 
exemption and the costs associated with the requirement to 
electronically submit compliance reports presented in section VIII.C of 
this preamble, there are no significant economic impacts from these 
proposed amendments

E. What are the benefits?

    The EPA did not propose changes to the emission limit requirements 
and estimates the proposed changes to SSM, recordkeeping, reporting, 
and monitoring are not economically significant. Because these proposed 
amendments are not considered economically significant, as defined by 
Executive Order 12866, and because no emission reductions were 
estimated, we did not estimate any benefits from reducing emissions.

VI. Request for Comments

    We solicit comments on this proposed action. In addition to general 
comments on this proposed action, we are also interested in additional 
data that may improve the risk assessments and other analyses. We are 
specifically interested in receiving any improvements to the data used 
in the site-specific emissions profiles used for risk modeling. Such 
data should include supporting documentation in sufficient detail to 
allow characterization of the quality and representativeness of the 
data or information. Section VII of this preamble provides more 
information on submitting data.
    We specifically solicit comment on an additional issue under 
consideration that could reduce regulatory burden for owners or 
operators of certain engine test cells/stands facilities. Currently, if 
an affected source owner or operator elects to comply with the percent 
reduction emission limitation, an initial performance test must be 
conducted to determine the capture and control efficiencies of the 
equipment and to establish the operating limits to be achieved on a 
continuous basis. Performance tests are to be conducted under 
representative operating conditions and the source is required to 
document the operating conditions during the test and explain why the 
conditions represent normal operation. Industry stakeholders have 
raised the issue that, for facilities with multiple test cells/stands, 
it is difficult to define ``normal'' operation due to the several types 
of engine tests conducted, the varying operation conditions for the 
engine tests, the number of cells/stands, different kinds of test 
fuels, and the complex emission capture system. Thus, affected sources 
have felt the need to request approval on the testing protocol prior to 
conducting the performance tests to limit tests to representative 
cells. We are requesting comment on whether this process of requesting 
prior approval for determining what is considered ``normal'' operation 
for a specific affected facility is reasonable and appropriate for the 
one-time required performance test.

VII. Submitting Data Corrections

    The site-specific emissions profiles used in the source category 
risk and demographic analyses and instructions are available for 
download on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html. The data files include detailed information for each HAP 
emissions release point for the facilities in the source category.
    If you believe that the data are not representative or are 
inaccurate, please identify the data in question, provide your reason 
for concern, and provide any ``improved'' data that you have, if 
available. When you submit data, we request that you provide 
documentation of the basis for the revised values to support your 
suggested changes. To submit comments on the data downloaded from the 
RTR website, complete the following steps:
    1. Within this downloaded file, enter suggested revisions to the 
data fields appropriate for that information.
    2. Fill in the commenter information fields for each suggested 
revision (i.e., commenter name, commenter organization, commenter email 
address, commenter phone number, and revision comments).
    3. Gather documentation for any suggested emissions revisions 
(e.g., performance test reports, material balance calculations).
    4. Send the entire downloaded file with suggested revisions in 
Microsoft[supreg] Access format and all accompanying documentation to 
Docket ID No. EPA-HQ-OAR-2018-0753 (through the method described in the 
ADDRESSES section of this preamble).
    5. If you are providing comments on a single facility or multiple 
facilities, you need only submit one file for all facilities. The file 
should contain all suggested changes for all sources at that facility 
(or facilities). We request that all data revision comments be 
submitted in the form of updated Microsoft[supreg] Excel files that are 
generated by the Microsoft[supreg] Access file. These files are 
provided on the RTR website at https://www3.epa.gov/ttn/atw/rrisk/rtrpg.html.

VIII. 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 Regulation and Regulatory Review

    This action is not a significant regulatory action and was, 
therefore, not submitted to OMB for review.

B. Executive Order 13771: Reducing Regulations and Controlling 
Regulatory Costs

    This action is not expected to be an Executive Order 13771 
regulatory action because this action is not significant under 
Executive Order 12866.

C. Paperwork Reduction Act (PRA)

    The information collection activities in this proposed rule have 
been submitted for approval to OMB under the PRA. The Information 
Collection Request (ICR) document that the EPA prepared has been 
assigned EPA ICR number 2066.08. You can find a copy of the ICR in the 
docket for this rule, and it is briefly summarized here.
    We are proposing changes to the reporting and recordkeeping 
requirements for the Engine Test Cells/Stands NESHAP in the form of 
eliminating the SSM reporting and SSM plan requirements and requiring 
electronic submittal of all compliance reports (including performance 
test reports). Any information submitted to the Agency for which a 
claim of confidentiality is made will be safeguarded according to the 
Agency policies set forth in title 40, chapter 1, part 2, subpart B--
Confidentiality of Business Information (see 40 CFR part 2; 41 FR 
36902, September 1, 1976; amended by 43 FR 40000, September 8, 1978; 43 
FR 42251, September 20, 1978; 44 FR 17674, March 23, 1979).
    Respondents/affected entities: Respondents are owners and operators 
of engine test cells/stands facilities subject to the Engine Test 
Cells/Standards NESHAP.

[[Page 20232]]

    Respondent's obligation to respond: Mandatory (40 CFR part 63, 
subpart PPPPP).
    Estimated number of respondents: On average over the next 3 years, 
approximately 12 existing major sources will be subject to these 
standards, of which seven are subject to emission limits, monitoring, 
recordkeeping, and reporting requirements. It is also estimated that 
one additional respondent will become subject to the emission standards 
over the 3-year period and two additional respondents will be subject 
only to the notification requirements.
    Frequency of response: The average number of respondents over the 
3-year period of this ICR is eight.
    Total estimated burden: The average annual burden to industry over 
the next 3 years from these recordkeeping and reporting requirements is 
estimated to be 1,000 hours (per year). Burden is defined at 5 CFR 
1320.3(b).
    Total estimated cost: The total capital/startup costs for this ICR 
are $500. The total operation and maintenance (O&M) costs for this ICR 
are $2,400. The average annual cost for capital/startup and O&M costs 
to industry over the next 3 years of the ICR is estimated to be $2,900. 
These are the recordkeeping costs.
    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 the 
EPA's regulations in 40 CFR 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 
OIRA_submission@omb.eop.gov, Attention: Desk Officer for the 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 June 7, 
2019. The EPA will respond to any ICR-related comments in the final 
rule.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, the impact of concern is any significant 
adverse economic impact on small entities. During the original 
rulemaking, an ICR was sent to over 100 companies representing over 300 
individual facilities. Using that information, along with discussion 
with industry stakeholders, it was determined that there were no major 
sources that were also small businesses. Thus, this action will not 
impose any requirements on small entities.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. The action imposes no enforceable duty on any state, 
local, or tribal governments or the private sector.

F. 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. The action 
affects private industry and does not impose economic costs on state or 
local governments.

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

    This action does not have tribal implications as specified in 
Executive Order 13175. The EPA does not know of any engine test cell/
stand facilities owned or operated by Indian tribal governments. Thus, 
Executive Order 13175 does not apply to this action.

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

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children. This action's health and risk assessments are contained in 
sections III and IV of this preamble and further documented in the risk 
report titled Residual Risk Assessment for the Engine Test Cells/Stands 
Source Category in Support of the 2019 Risk and Technology Review 
Proposed Rule, which is available in the docket for this action.

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

    This action is not subject to Executive Order 13211, because it is 
not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards.

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

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994).
    The documentation for this decision is contained in section IV.B of 
this preamble and the technical report, Risk and Technology Review 
Analysis of Demographic Factors for Populations Living Near Engine Test 
Cells/Stands Source Category Operations.

List of Subjects in 40 CFR Part 63

    Environmental protection, Air pollution control, Engine test cells/
stands, Hazardous substances, Incorporation by reference, Reporting and 
recordkeeping requirements.

    Dated: April 25, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons stated in the preamble, 40 CFR part 63 is proposed 
to be amended as follows:

PART 63--NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS 
FOR SOURCE CATEGORIES

0
1. The authority citation for part 63 continues to read as follows:

    Authority: 42 U.S.C. 7401 et seq.

Subpart PPPPP--[Amended]

0
 2. Section 63.9295 is amended by revising paragraphs (a)(1) and (a)(2) 
and adding paragraph (a)(3) to read as follows:


Sec.  63.9295  When do I have to comply with this subpart?

    (a) Affected sources. (1) If you start up your new or reconstructed 
affected source before May 27, 2003, you must comply with the emission 
limitations in this subpart no later than May 27, 2003;

[[Page 20233]]

except that the compliance date for the revised requirements 
promulgated at Sec. Sec.  63.9295, 63.9305, 63.9340, 63.9350, 63.9355, 
63.9375, and Table 7 of 40 CFR part 63, subpart PPPPP, published on 
[DATE OF PUBLICATION OF FINAL RULE IN THE Federal Register] is [DATE 
180 DAYS AFTER THE DATE OF PUBLICATION OF FINAL RULE IN THE Federal 
Register].
    (2) If you start up your new or reconstructed affected source on or 
after May 27, 2003, you must comply with the emission limitations in 
this subpart upon startup; except that if the initial startup of your 
new or reconstructed affected source occurs after May 27, 2003, but on 
or before May 8, 2019, the compliance date for the revised requirements 
promulgated at Sec. Sec.  63.9295, 63.9305, 63.9340, 63.9350, 63.9355, 
63.9375, and Table 7 of this subpart published on [DATE OF PUBLICATION 
OF FINAL RULE IN THE Federal Register] is [DATE 180 DAYS AFTER THE DATE 
OF PUBLICATION OF FINAL RULE IN THE Federal Register].
    (3) If the initial startup of your new or reconstructed affected 
source occurs after May 8, 2019, the compliance date is [DATE OF 
PUBLICATION OF FINAL RULE IN THE Federal Register] or the date of 
startup, whichever is later.
* * * * *
0
3. Section 63.9305 is revised to read as follows:


Sec.  63.9305  What are my general requirements for complying with this 
subpart?

    (a) Prior to [DATE 181 DAYS AFTER DATE OF PUBLICATION OF FINAL RULE 
IN THE Federal Register], You must be in compliance with the emission 
limitation that applies to you at all times, except during periods of 
startup, shutdown, or malfunction (SSM) of your control device or 
associated monitoring equipment. After [DATE 180 DAYS AFTER PUBLICATION 
OF FINAL RULE IN THE Federal Register], you must be in compliance with 
the applicable emission limitation at all times.
    (b) If you must comply with the emission limitation, you must 
operate and maintain your engine test cell/stand, air pollution control 
equipment, and monitoring equipment in a manner consistent with safety 
and good air pollution control practices for minimizing emissions at 
all times. The general duty to minimize emissions does not require the 
owner or operator to make any further efforts to reduce emissions if 
levels required by the applicable standard have been achieve. 
Determination of whether a source is operating in compliance with 
operation and maintenance requirements will be based on information 
available to the Administrator that may include, but is not limited to, 
monitoring results, review of operation and maintenance procedures, 
review of operation and maintenance records, and inspection of the 
affected source.
    (c) For affected sources until [DATE 180 DAYS AFTER DATE OF 
PUBLICATION OF FINAL RULE IN THE Federal Register], You must develop a 
written SSM plan (SSMP) for emission control devices and associated 
monitoring equipment according to the provisions in Sec.  63.6(e)(3). 
The plan will apply only to emission control devices, and not to engine 
test cells/stands.
0
 4. Section 63.9307 is amended by revising paragraphs (c)(1), (2), and 
(4) to read as follows:


Sec.  63.9307  What are my continuous emissions monitoring system 
installation, operation, and maintenance requirements?

* * * * *
    (c) To comply with either emission limitations, the CEMS must be 
installed and operated according to the requirements described in 
paragraphs (c)(1) through (4) of this section.
    (1) You must install, operate, and maintain each CEMS according to 
the applicable Performance Specification (PS) of 40 CFR part 60, 
appendix B (PS- 3, PS-4A, or PS-8).
    (2) You must conduct a performance evaluation of each CEMS 
according to the requirements in 40 CFR 63.8 and according to PS-3 of 
40 CFR part 60, appendix B, using Reference Method 3A or 3B for the 
O2 CEMS, and according to PS-4A of 40 CFR part 60, appendix 
B, using Reference Method 10 or 10B for the CO CEMS, and according to 
PS-8 of CFR part 60, Appendix B, using Reference Method 25A for the THC 
CEMS. If the fuel used in the engines being tested is natural gas, you 
may use ASTM D 6522-00, Standard Test Method for Determination of 
Nitrogen Oxides, Carbon Monoxide and Oxygen Concentrations in Emissions 
from Natural Gas Fired Reciprocating Engines, Combustion Turbines, 
Boilers, and Process Heaters Using Portable Analyzers (incorporated by 
reference, see Sec.  63.14). As an alternative to Method 3B, you may 
use ANSI/ASME PTC 19.10-1981, ``Flue and Exhaust Gas Analyses [Part 10, 
Instruments and Apparatus],'' (incorporated by reference, see Sec.  
63.14).
* * * * *
    (4) All CEMS data must be reduced as specified in Sec.  63.8(g)(2) 
and recorded as CO or THC as carbon concentration in parts per million 
by volume, dry basis (ppmvd), corrected to 15 percent O2 
content.
* * * * *
0
 5. Section 63.9320 is amended by revising paragraphs (b) and (c) to 
read as follows:


Sec.  63.9320   What procedures must I use?

* * * * *
    (b) You must conduct an initial performance evaluation of each 
capture and control system according to Sec. Sec.  63.9321, 63.9322, 
63.9323 and 63.9324, and each CEMS according to the requirements in 40 
CFR 63.8 and according to the applicable Performance Specification of 
40 CFR part 60, appendix B (PS- 3, PS-4A, or PS-8).
    (c) The initial demonstration of compliance with the carbon 
monoxide (CO) or total hydrocarbon (THC) concentration limitation 
consists of either the first 4-hour rolling average CO or THC 
concentration recorded after completion of the CEMS performance 
evaluation if CEMS are installed or the average of the test run 
averages during the initial performance test. You must correct the CO 
or THC concentration at the outlet of the engine test cell/stand or the 
emission control device to a dry basis and to 15 percent O2 
content according to Equation 1 of this section:
[GRAPHIC] [TIFF OMITTED] TP08MY19.005


Where:

Cc = concentration of CO or THC, corrected to 15 percent 
oxygen, ppmvd
Cunc = total uncorrected concentration of CO or THC, 
ppmvd
%O2d = concentration of oxygen measured in gas stream, 
dry basis, percent by volume
* * * * *
0
6. Section 63.9330 is amended by revising paragraph (a) to read as 
follows:


Sec.  63.9330  How do I demonstrate initial compliance with the 
emission limitation?

    (a) You must demonstrate initial compliance with the emission 
limitation that applies to you according to Table 4 to this subpart.
* * * * *
0
 7. Section 63.9340 is amended by revising paragraph (c) to read as 
follows:


Sec.  63.9340  How do I demonstrate continuous compliance with the 
emission limitations?

* * * * *
    (c) Startups, shutdowns, and malfunctions. (1) For affected sources 
until [DATE 180 DAYS AFTER THE DATE OF PUBLICATION OF FINAL RULE IN 
Federal Register], consistent with Sec. Sec.  63.6(e) and 63.7(e)(1), 
deviations that occur during a period of

[[Page 20234]]

SSM of control devices and associated monitoring equipment are not 
violations if you demonstrate to the Administrator's satisfaction that 
you were operating in accordance with Sec.  63.6(e)(1).
    (2) The Administrator will determine whether deviations that occur 
during a period you identify as an SSM of control devices and 
associated monitoring equipment are violations, according to the 
provisions in Sec.  63.6(e).
0
8. Section 63.9350 is amended by:
0
a. Revising paragraph (a)(6) and;
0
b. Adding paragraph (a)(7);
0
c. Revising paragraph (c) introductory text;
0
d. Adding paragraphs (c)(5);
0
e. Revising paragraph (d) introductory text;
0
f. Adding paragraph (d)(11);
0
g. Revising paragraph (e);
0
h. Adding paragraphs (f) through (i).
    The revisions and additions read as follows:


Sec.  63.9350  What reports must I submit and when?

    (a) * * *
    (6) For affected sources until [DATE 180 DAYS AFTER DATE OF 
PUBLICATION OF FINAL RULE IN Federal Register], if you had an SSM of a 
control device or associated monitoring equipment during the reporting 
period and you took actions consistent with your SSMP, the compliance 
report must include the information in paragraphs Sec.  63.10(d)(5)(i).
    (7) Beginning on [DATE 180 DAYS AFTER DATE OF PUBLICATION OF FINAL 
RULE IN Federal Register], submit all semiannual compliance reports 
following the procedure specified in paragraph (g) of this section.
* * * * *
    (c) For each deviation from an emission limit, the semiannual 
compliance report must include the information in paragraphs (b)(1) 
through (3) of this section and the information included in paragraphs 
(c)(1) through (4) of this section, except that after [DATE 180 DAYS 
AFTER DATE OF PUBLICATION OF FINAL RULE IN Federal Register] the 
semiannual compliance report must also include the information included 
in paragraph (c)(5) of this section.
* * * * *
    (5) An estimate of the quantity of each regulated pollutant emitted 
over any emission limit, and a description of the method used to 
estimate the emissions.
* * * * *
    (d) For each CEMS or CPMS deviation, the semiannual compliance 
report must include the information in paragraphs (b)(1) through (3) of 
this section and the information included in paragraphs (d)(1) through 
(10) of this section, except that after [DATE 180 DAYS AFTER DATE OF 
PUBLICATION OF FINAL RULE IN Federal Register] the semiannual 
compliance report must also include the information included in 
paragraph (d)(11) of this section.
* * * * *
    (11) The total operating time of each new or reconstructed engine 
test cell/stand during the reporting period.
* * * * *
    (e) Until [DATE 180 DAYS AFTER DATE OF PUBLICATION OF FINAL RULE IN 
THE Federal Register], if you had an SSM of a control device or 
associated monitoring equipment during the semiannual reporting period 
that was not consistent with your SSMP, you must submit an immediate 
SSM report according to the requirements in Sec.  63.10(d)(5)(ii).
    (f) Within 60 days after the date of completing each performance 
test or performance evaluation required by this subpart, you must 
submit the results of the performance test following the procedures 
specified in paragraphs (f)(1) through (3) of this section.
    (1) Data collected or performance evaluations of CMS measuring 
relative accuracy test audit (RATA) pollutants using test methods 
supported by the EPA's Electronic Reporting Tool (ERT) as listed on the 
EPA's ERT website (https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert) at the time of the test. 
Submit the results of the performance test or performance evaluation to 
the EPA via the Compliance and Emissions Data Reporting Interface 
(CEDRI), which can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). The data must be submitted in a file 
format generated through the use of the EPA's ERT. Alternatively, you 
may submit an electronic file consistent with the extensible markup 
language (XML) schema listed on the EPA's ERT website.
    (2) Data collected or performance evaluations of CMS measuring 
relative accuracy test audit (RATA) pollutants using test methods that 
are not supported by the EPA's ERT as listed on the EPA's ERT website 
at the time of the test. The results of the performance test or 
performance evaluation must be included as an attachment in the ERT or 
an alternate electronic file consistent with the XML schema listed on 
the EPA's ERT website. Submit the ERT generated package or alternative 
file to the EPA via CEDRI.
    (3) Confidential business information (CBI). If you claim some of 
the information submitted under paragraph (f) of this section is CBI, 
you must submit a complete file, including information claimed to be 
CBI, to the EPA. The file must be generated through the use of the 
EPA's ERT or an alternate electronic file consistent with the XML 
schema listed on the EPA's ERT website. Submit the file on a compact 
disc, flash drive, or other commonly used electronic storage medium and 
clearly mark the medium as CBI. Mail the electronic medium to U.S. EPA/
OAQPS/CORE CBI Office, Attention: Group Leader, Measurement Policy 
Group, MD C404-02, 4930 Old Page Rd., Durham, NC 27703. The same file 
with the CBI omitted must be submitted to the EPA via the EPA's CDX as 
described in paragraph (f)(1) of this section.
    (g) If you are required to submit reports following the procedure 
specified in this paragraph, you must submit reports to the EPA via 
CEDRI, which can be accessed through the EPA's Central Data Exchange 
(CDX) (https://cdx.epa.gov/). You must use the appropriate electronic 
report template on the CEDRI website (https://www.epa.gov/electronic-reporting-air-emissions/compliance-and-emissions-data-reporting-interface-cedri) for this subpart. The report must be submitted by the 
deadline specified in this subpart, regardless of the method in which 
the report is submitted. If you claim some of the information required 
to be submitted via CEDRI is confidential business information (CBI), 
submit a complete report, including information claimed to be CBI, to 
the EPA. The report must be generated using the appropriate form on the 
CEDRI website. Submit the file on a compact disc, flash drive, or other 
commonly used electronic storage medium and clearly mark the medium as 
CBI. Mail the electronic medium to U.S. EPA/OAQPS/CORE CBI Office, 
Attention: Group Leader, Measurement Policy Group, MD C404-02, 4930 Old 
Page Rd., Durham, NC 27703. The same file with the CBI omitted must be 
submitted to the EPA via the EPA's CDX as described earlier in this 
paragraph.
    (h) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX, you may assert a claim of EPA system outage for 
failure to timely comply with the reporting requirement. To assert a 
claim of EPA system outage, you must meet the requirements outlined in 
paragraphs (h)(1) through (7) of this section.

[[Page 20235]]

    (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 EPA's CEDRI or CDX systems.
    (2) The outage must have occurred within the period of time 
beginning five business days prior to the date that the submission is 
due.
    (3) The outage may be planned or unplanned.
    (4) 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.
    (5) 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 EPA system outage;
    (iii) 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.
    (6) The decision to accept the claim of EPA system outage and allow 
an extension to the reporting deadline is solely within the discretion 
of the Administrator.
    (7) In any circumstance, the report must be submitted 
electronically as soon as possible after the outage is resolved.
    (i) If you are required to electronically submit a report through 
CEDRI in the EPA's CDX, you may assert a claim of force majeure for 
failure to timely comply with the reporting requirement. To assert a 
claim of force majeure, you must meet the requirements outlined in 
paragraphs (i)(1) through (5) 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 of time 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 within the time period prescribed. 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) 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) 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.
    (5) In any circumstance, the reporting must occur as soon as 
possible after the force majeure event occurs.
0
9. Section 63.9355 is amended by revising paragraph (a) introductory 
text and paragraph (a)(3) and adding paragraphs (a)(6) through (8) to 
read as follows:


Sec.  63.9355   What records must I keep?

    (a) You must keep the records as described in paragraphs (a)(1) 
through (5) of this section. After [DATE OF PUBLICATION OF FINAL RULE 
IN Federal Register], you must also keep the records as described in 
paragraphs (a)(6) through (8) of this section.
* * * * *
    (3) Records of the occurrence and duration of each malfunction of 
the air pollution control equipment, if applicable, as required in 
Sec.  63.9355.
* * * * *
    (6) In the event that an affected unit fails to meet an applicable 
standard, record the number of failures. For each failure record the 
date, time and duration of each failure.
    (7) For each failure to meet an applicable standard, record and 
retain a list of the affected sources or equipment, an estimate of the 
quantity of each regulated pollutant emitted over any emission limit, 
and a description of the method used to estimate the emissions.
    (8) Record actions taken to minimize emissions in accordance with 
Sec.  63.9305, and any corrective actions taken to return the affected 
unit to its normal or usual manner of operation.
* * * * *
0
 10. Section 63.9360 is amended by adding paragraph (d) to read as 
follows;


Sec.  63.9360  In what form and how long must I keep my records?

* * * * *
    (d) Any records required to be maintained by this part that are 
submitted electronically via the 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 delegated air agency or the EPA as 
part of an on-site compliance evaluation.
0
 11. Section 63.9375 is amended by revising paragraph (3) under the 
definition for ``Deviation'' to read as follows:


Sec.  63.9375  What definitions apply to this subpart?

* * * * *
    Deviation * * *
* * * * *
    (3) Until [DATE 180 DAYS AFTER DATE OF PUBLICATION OF FINAL RULE IN 
Federal Register], fails to meet any emission limitation or operating 
limit in this subpart during malfunction, regardless or whether or not 
such failure is permitted by this subpart.
* * * * *
0
12. Table 3 to subpart PPPPP is amended by revising the entry for ``1. 
The CO or THC outlet concentration emission limitation'' to read as 
follows:

Table 3 to Subpart PPPPP of Part 63--Requirements for Initial 
Compliance Demonstrations

    As stated in Sec.  63.9321, you must demonstrate initial compliance 
with each emission limitation that applies to you according to the 
following table:

[[Page 20236]]



----------------------------------------------------------------------------------------------------------------
                                                                                             According to the
    For each new or reconstructed           You must . . .            Using . . .         following requirements
 affected source complying with . . .                                                             . . .
----------------------------------------------------------------------------------------------------------------
1. The CO or THC outlet concentration  a. Demonstrate CO or     i. EPA Methods 3A and    You must demonstrate
 emission limitation.                   THC emissions are 20     10 of appendix A to 40   that the outlet
                                        ppmvd or less.           CFR part 60 for CO       concentration of CO or
                                                                 measurement or EPA       THC emissions from the
                                                                 Method 25A of appendix   test cell/stand or
                                                                 A to 40 CFR part 60      emission control
                                                                 for THC measurement;     device is 20 ppmvd or
                                                                 or.                      less, corrected to 15
                                                                                          percent O2 content,
                                                                                          using the average of
                                                                                          the test runs in the
                                                                                          performance test.
                                                                ii. A CEMS for CO or     This demonstration is
                                                                 THC and O2 at the        conducted immediately
                                                                 outlet of the engine     following a successful
                                                                 test cell/stand or       performance evaluation
                                                                 emission control         of the CEMS as
                                                                 device.                  required in Sec.
                                                                                          63.9320(b). The
                                                                                          demonstration consists
                                                                                          of the first 4-hour
                                                                                          rolling average of
                                                                                          measurements. The CO
                                                                                          or THC concentration
                                                                                          must be corrected to
                                                                                          15 percent O2 content,
                                                                                          dry basis using
                                                                                          Equation 1 in Sec.
                                                                                          63.9320.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

0
13. Table 4 of subpart PPPPP is revised to read as follows:

Table 4 to Subpart PPPPP of Part 63--Initial Compliance With Emission 
Limitations

    As stated in Sec.  63.9330, you must demonstrate initial compliance 
with each emission limitation that applies to you according to the 
following table:

------------------------------------------------------------------------
                                        You have demonstrated initial
           For the . . .                     compliance if . . .
------------------------------------------------------------------------
1. CO or THC concentration          The first 4-hour rolling average CO
 emission limitation.                or THC concentration is 20 ppmvd or
                                     less, corrected to 15 percent O2
                                     content if CEMS are installed or
                                     the average of the test run
                                     averages during the performance
                                     test is 20 ppmvd or less, corrected
                                     to 15 percent O2 content.
2. CO or THC percent reduction      The first 4-hour rolling average
 emission limitation.                reduction in CO or THC is 96
                                     percent or more, dry basis,
                                     corrected to 15 percent O2 content.
------------------------------------------------------------------------

0
14. Table 5 of subpart PPPPP is revised to read as follows:

Table 5 to Subpart PPPPP of Part 63--Continuous Compliance With 
Emission Limitations

    As stated in Sec.  63.9340, you must demonstrate continuous 
compliance with each emission limitation that applies to you according 
to the following table:

------------------------------------------------------------------------
          For the . . .             You must . . .         By . . .
------------------------------------------------------------------------
1. CO or THC concentration        a. Demonstrate CO   i. Collecting the
 emission limitation.              or THC emissions    CPMS data
                                   are 20 ppmvd or     according to Sec.
                                   less over each 4-     63.9306(a),
                                   hour rolling        reducing the
                                   averaging period.   measurements to 1-
                                                       hour averages
                                                       used to calculate
                                                       the 3-hr block
                                                       average; or
                                                      ii. Collecting the
                                                       CEMS data
                                                       according to Sec.
                                                         63.9307(a),
                                                       reducing the
                                                       measurements to 1-
                                                       hour averages,
                                                       correcting them
                                                       to 15 percent O2
                                                       content, dry
                                                       basis, according
                                                       to Sec.
                                                       63.9320.
2. CO or THC percent reduction    a. Demonstrate a    i. Collecting the
 emission limitation.              reduction in CO     CPMS data
                                   or THC of 96        according to Sec.
                                   percent or more       63.9306(a),
                                   over each 4-hour    reducing the
                                   rolling averaging   measurements to 1-
                                   period.             hour averages; or
                                                      ii. Collecting the
                                                       CEMS data
                                                       according to Sec.
                                                         63.9307(b),
                                                       reducing the
                                                       measurements to 1-
                                                       hour averages,
                                                       correcting them
                                                       to 15 percent O2
                                                       content, dry
                                                       basis,
                                                       calculating the
                                                       CO or THC percent
                                                       reduction
                                                       according to Sec.
                                                         63.9320.
------------------------------------------------------------------------


[[Page 20237]]

0
15. Table 7 of subpart PPPPP is revised to read as follows:

Table 7 to Subpart PPPPP of Part 63--Applicability of General 
Provisions to Subpart PPPPP

    As stated in 63.9365, you must comply with the General Provisions 
in Sec. Sec.  63.1 through 63.15 that apply to you according to the 
following table:

------------------------------------------------------------------------
                                         Applicable to
       Citation            Subject       subpart PPPPP     Explanation
------------------------------------------------------------------------
Sec.   63.1(a)(1)-     General          Yes.             ...............
 (12).                  Applicability.
Sec.   63.1(b)(1)-(3)  Initial          Yes............  Applicability
                        Applicability                     to subpart
                        Determination.                    PPPPP is also
                                                          specified in
                                                          Sec.
                                                          63.9285.
Sec.   63.1(c)(1)....  Applicability    Yes.             ...............
                        After Standard
                        Established.
Sec.   63.1(c)(2)....  Applicability    No.............  Area sources
                        of Permit                         are not
                        Program for                       subject to
                        Area Sources.                     subpart PPPPP.
Sec.   63.1(c)(5)....  Notifications..  Yes.             ...............
Sec.   63.1(d).......  [Reserved].....
Sec.   63.1(e).......  Applicability    Yes.             ...............
                        of Permit
                        Program Before
                        Relevant
                        Standard is
                        Set.
Sec.   63.2..........  Definitions....  Yes............  Additional
                                                          definitions
                                                          are specified
                                                          in Sec.
                                                          63.9375.
Sec.   63.3..........  Units and        Yes.             ...............
                        Abbreviations.
Sec.   63.4..........  Prohibited       Yes.             ...............
                        Activities and
                        Circumvention.
Sec.   63.5(a).......  Construction/    Yes.             ...............
                        Reconstruction.
Sec.   63.5(b).......  Requirements     Yes.             ...............
                        for Existing,
                        Newly
                        Constructed,
                        and
                        Reconstruction
                        Sources.
Sec.   63.5(d).......  Application for  Yes.             ...............
                        Approval of
                        Construction/
                        Reconstruction.
Sec.   63.5(e).......  Approval of      Yes.             ...............
                        Construction/
                        Reconstruction.
Sec.   63.5(f).......  Approval of      Yes.             ...............
                        Construction/
                        Reconstruction
                        based on Prior
                        State Review.
Sec.   63.6(a).......  Compliance With  Yes.             ...............
                        Standards and
                        Maintenance
                        Requirements--
                        Applicability.
Sec.   63.6(b)(1)-(7)  Compliance       Yes............  Sec.   63.9295
                        Dates for New                     specifies the
                        and                               compliance
                        Reconstructed                     dates.
                        Sources.
Sec.   63.6(c)(1)-(2)  Compliance       No.............  Subpart PPPPP
                        Dates for                         does not
                        Existing                          establish
                        Sources.                          standards for
                                                          existing
                                                          sources.
Sec.   63.6(c)(5)....  Compliance       Yes............  Sec.
                        Dates for                         63.9295(b)
                        Existing                          specifies the
                        Sources.                          compliance
                                                          date if a new
                                                          or
                                                          reconstructed
                                                          area source
                                                          becomes a
                                                          major source.
Sec.   63.6(e)(1)(i).  Operation and    No.............  See Sec.
                        Maintenance.                      63.9305 for
                                                          general duty
                                                          requirement.
Sec.   63.6(e)(1)(ii)  Operation and    No.              ...............
                        Maintenance.
Sec.                   Operation and    Yes.             ...............
 63.6(e)(1)(iii).       Maintenance.
Sec.   63.6(e)(3)....  SSM Plan.......  No.              ...............
Sec.   63.6(f)(1)....  Compliance       No.              ...............
                        Except During
                        Startup,
                        Shutdown, and
                        Malfunction.
Sec.   63.6(f)(2)-(3)  Methods for      Yes.             ...............
                        Determining
                        Compliance.
Sec.   63.6(g)(1)-(3)  Use of           Yes.             ...............
                        Alternative
                        Standards.
Sec.   63.6(h).......  Compliance With  No.............  Subpart PPPPP
                        Opacity/                          does not
                        Visible                           establish
                        Emission                          opacity
                        Standards.                        standards and
                                                          does require
                                                          continuous
                                                          opacity
                                                          monitoring
                                                          systems
                                                          (COMS).
Sec.   63.6(i)(1)-     Extension of     No.............  Compliance
 (16).                  Compliance.                       extension
                                                          provisions
                                                          apply to
                                                          existing
                                                          sources which
                                                          do not have
                                                          emission
                                                          limitations in
                                                          subpart PPPPP.
Sec.   63.6(j).......  Presidential     Yes.             ...............
                        Compliance
                        Exemption.
Sec.   63.7(a)(1)-(2)  Performance      Yes.             ...............
                        Test Dates.
Sec.   63.7(a)(3)....  Performance      Yes.             ...............
                        Test Required
                        By the
                        Administrator.
Sec.   63.7(b)-(d)...  Performance      Yes.             ...............
                        Test
                        Requirements-
                        Notification,
                        Quality
                        Assurance,
                        Facilities
                        Necessary for
                        Safe Testing,
                        Conditions
                        During Testing.
Sec.   63.7(e)(1)....  Conditions for   No.              ...............
                        Conducting
                        Performance
                        Tests.
Sec.   63.7(e)(2)-(4)  Conduct of       Yes.             ...............
                        Performance
                        Tests.
Sec.   63.7(f).......  Alternative      Yes.             ...............
                        Test Methods.
Sec.   63.7(g)-(h)...  Performance      Yes.             ...............
                        Testing
                        Requirements--
                        Data Analysis,
                        Recordkeeping,
                        Reporting,
                        Waiver of Test.
Sec.   63.8(a)(1)-(2)  Monitoring       Yes............  Subpart PPPPP
                        Requirements--                    contains
                        Applicability.                    specific
                                                          requirement
                                                          for monitoring
                                                          at Sec.
                                                          63.9325.
Sec.   63.8(a)(4)....  Additional       No.............  Subpart PPPPP
                        Monitoring                        does not have
                        Requirements.                     monitoring
                                                          requirement
                                                          for flares.
Sec.   63.8(b).......  Conduct of       Yes.             ...............
                        Monitoring.
Sec.   63.8(c)(1)....  Continuous       Yes.             ...............
                        Monitoring
                        System (CMS)
                        Operation and
                        Maintenance.
Sec.   63.8(c)(1)(i).  General Duty to  No.              ...............
                        Minimize
                        Emissions and
                        CMS Operation.
Sec.   63.8(c)(1)(ii)  Operation and    Yes.             ...............
                        Maintenance of
                        CMS.
Sec.                   Requirement to   No.              ...............
 63.8(c)(1)(iii).       Develop SSM
                        Plan for CMS.
Sec.   63.8(c)(2)-(3)  Monitoring       Yes.             ...............
                        System
                        Installation.
Sec.   63.8(c)(4)....  CMS............  No.............  Sec.
                                                          63.9335(a) and
                                                          (b) specifies
                                                          the
                                                          requirements
Sec.   63.8(c)(5)....  COMS...........  No.............  Subpart PPPPP
                                                          does not have
                                                          opacity or VE
                                                          standards.
Sec.   63.8(c)(6)-(8)  CMS              Yes............  Except that
                        Requirements.                     subpart PPPPP
                                                          does not
                                                          require COMS.
Sec.   63.8(d)-(e)...  CMS Quality      Yes............  Except for Sec.
                        Control and
                        CMS                               63.8(e)(5)(ii)
                        Performance.                      which applies
                                                          to COMS.
Sec.   63.8(f)(1)-(5)  Alternative      Yes.             ...............
                        Monitoring
                        Method.
Sec.   63.8(f)(6)....  Alternative to   Yes.             ...............
                        Relative
                        Accuracy Test.
Sec.   63.8(g).......  Data Reduction.  No.............  Sec.  Sec.
                                                          63.9335 and
                                                          63.9340
                                                          specify
                                                          monitoring
                                                          data
                                                          reduction.
Sec.   63.9(a)-(b)...  Notification     Yes.             ...............
                        Requirements.
Sec.   63.9(c).......  Request for      No.............  Compliance
                        Compliance                        extension to
                        Extension.                        not apply to
                                                          new or
                                                          reconstructed
                                                          sources.
Sec.   63.9(d).......  Notification of  Yes.             ...............
                        Special
                        Compliance
                        Requirements
                        for New
                        Sources.
Sec.   63.9(e).......  Notification of  No.............  Subpart PPPPP
                        Performance                       does not
                        Test.                             require
                                                          performance
                                                          testing.
Sec.   63.9(f).......  Notification of  No.............  Subpart PPPPP
                        Opacity/VE                        does not have
                        Test.                             opacity/VE
                                                          standards.

[[Page 20238]]

 
Sec.   63.9(g)(1)....  Additional       Yes.             ...............
                        Notifications
                        When Using CMS.
Sec.   63.9(g)(2)....  Additional       No.............  Subpart PPPPP
                        Notifications                     does not have
                        When Using CMS.                   opacity/VE
                                                          standards.
Sec.   63.9(g)(3)....  Additional       Yes.             ...............
                        Notifications
                        When Using CMS.
Sec.   63.9(h).......  Notification of  Yes.             ...............
                        Compliance
                        Status.
Sec.   63.9(i).......  Adjustment of    Yes.             ...............
                        Submittal
                        Deadlines.
Sec.   63.9(j).......  Change in        Yes.             ...............
                        Previous
                        Information.
Sec.   63.10(a)......  Recordkeeping/   Yes.             ...............
                        Reporting.
Sec.   63.10(b)(1)...  General          Yes.             ...............
                        Recordkeeping
                        Requirements.
Sec.   63.10(b)(2)(i)  Recordkeeping    No.              ...............
                        of Occurrence
                        and Duration
                        of Startups
                        and Shutdowns.
Sec.                   Recordkeeping    No.............  See Sec.
 63.10(b)(2)(ii).       of Occurrence                     63.9355 for
                        and Duration                      recordkeeping
                        of                                of (1) date,
                        Malfunctions.                     time and
                                                          duration; (2)
                                                          listing of
                                                          affected
                                                          source or
                                                          equipment, and
                                                          an estimate of
                                                          the quantity
                                                          of each
                                                          regulated
                                                          pollutant
                                                          emitted over
                                                          the standard;
                                                          and (3)
                                                          actions to
                                                          minimize
                                                          emissions and
                                                          correct the
                                                          failure.
Sec.                   Recordkeeping    Yes.             ...............
 63.10(b)(2)(iii).      of Maintenance
                        on Controls
                        and Monitoring
                        Equipment.
Sec.                   Actions Taken    No.              ...............
 63.10(b)(2)(iv)-(v).   to Minimize
                        Emissions
                        During SSM.
Sec.                   CMS Records....  Yes.             ...............
 63.10(b)(2)((vi)-(xi
 ).
Sec.                   Records........  Yes.             ...............
 63.10(b)(2)(xii).
Sec.                   Records........  Yes.             ...............
 63.10(b)(2)(xiii).
Sec.                   Records........  Yes.             ...............
 63.10(b)(2)(xiv).
Sec.   63.10(b)(3)...  Recordkeeping    Yes.             ...............
                        for
                        Applicability
                        Determinations.
Sec.   63.10(c)(1)-    Additional       Yes.             ...............
 (6), (9)-(14).         Recordkeeping
                        for CMS.
Sec.   63.10(c)(7)-    Records of       No.............  Specific
 (8).                   Excess                            language is
                        Emissions and                     located at
                        Parameter                         Sec.   63.9355
                        Monitoring                        of subpart
                        Exceedances                       PPPPP.
                        for CMS.
Sec.   63.10(c)(15)..  Records          No.              ...............
                        Regarding the
                        SSM Plan.
Sec.   63.10(d)(1)...  General          Yes.             ...............
                        Reporting
                        Requirements.
Sec.   63.10(d)(2)...  Report of        Yes.             ...............
                        Performance
                        Test Results.
Sec.   63.10(d)(3)...  Reporting of     No.............  Subpart PPPPP
                        Opacity or VE                     does not have
                        Observations.                     opacity/VE
                                                          standards.
Sec.   63.10(d)(4)...  Progress         No.............  Compliance
                        Reports for                       extensions do
                        Sources with                      not apply to
                        Compliance                        new or
                        Extensions.                       reconstructed
                                                          sources.
Sec.   63.10(d)(5)...  SSM Reports....  No. See Sec.     ...............
                                         63.9350 for
                                         malfunction
                                         reporting
                                         requirements.
Sec.   63.10(e)(1)     Additional CMS   Yes.             ...............
 and (2)(i).            Reports.
Sec.                   Additional CMS   No.............  Subpart PPPPP
 63.10(e)(2)(ii).       Reports.                          does not
                                                          require COMS.
Sec.   63.10(e)(3)...  Excess           No.............  Specific
                        Emissions/CMS                     language is
                        Performance                       located in
                        Reports.                          Sec.   63.9350
                                                          of subpart
                                                          PPPPP.
Sec.   63.10(e)(4)...  COMS Data        No.............  Subpart PPPPP
                        Reports.                          does not
                                                          require COMS.
Sec.   63.10(f)......  Waiver for       Yes.             ...............
                        Recordkeeping/
                        Reporting.
Sec.   63.11.........  Control Device   No.............  Subpart PPPPP
                        Requirements/                     does not
                        Flares.                           specify use of
                                                          flares for
                                                          compliance.
Sec.   63.12.........  State Authority  Yes.             ...............
                        and
                        Delegations.
Sec.   63.13.........  Addresses......  Yes.             ...............
Sec.   63.14.........  Incorporation    Yes............  ASTM D 6522-00
                        by Reference.                     and ANSI/ASME
                                                          PTC 19.10-1981
                                                          (incorporated
                                                          by reference-
                                                          See Sec.
                                                          63.14).
Sec.   63.15.........  Availability of  Yes.             ...............
                        Information/
                        Confidentialit
                        y.
------------------------------------------------------------------------

[FR Doc. 2019-09119 Filed 5-7-19; 8:45 am]
 BILLING CODE 6560-50-P


