[Federal Register Volume 84, Number 185 (Tuesday, September 24, 2019)]
[Proposed Rules]
[Pages 50244-50286]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-19876]



[[Page 50243]]

Vol. 84

Tuesday,

No. 185

September 24, 2019

Part VI





Environmental Protection Agency





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40 CFR Part 60





Oil and Natural Gas Sector: Emission Standards for New, Reconstructed, 
and Modified Sources Review; Proposed rule

  Federal Register / Vol. 84 , No. 185 / Tuesday, September 24, 2019 / 
Proposed Rules  

[[Page 50244]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2017-0757; FRL-9999-50-OAR]
RIN 2060-AT90


Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This action proposes reconsideration amendments to the new 
source performance standards (NSPS). These amendments, if finalized, 
would remove sources in the transmission and storage segment from the 
source category, rescind the NSPS (including both the volatile organic 
compounds (VOC) and methane requirements) applicable to those sources, 
and rescind the methane-specific requirements (the ``methane 
requirements'') of the NSPS applicable to sources in the production and 
processing segments. The U.S. Environmental Protection Agency (EPA) is 
also proposing, as an alternative, to rescind the methane requirements 
of the NSPS applicable to all oil and natural gas sources, without 
removing any sources from the source category. Furthermore, the EPA is 
taking comment on alternative interpretations of its statutory 
authority to regulate pollutants under the Clean Air Act (CAA), and 
associated record and policy questions.

DATES: Comments. Comments must be received on or before November 25, 
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 October 24, 2019.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2017-0757, at https://www.regulations.gov/, 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-2017-0757 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2017-0757.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2017-0757, 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 SUPPLEMENTAL INFORMATION 
section of this document.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Ms. Amy Hambrick, Sector Policies and Programs Division 
(E143-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-0964; fax number: (919) 541-0516; 
and email address: hambrick.amy@epa.gov. For information about the 
applicability of the NSPS to a particular entity, contact Ms. Marcia 
Mia, Office of Enforcement and Compliance Assurance, U.S. Environmental 
Protection Agency, WJC South Building (Mail Code 2227A), 1200 
Pennsylvania Avenue NW, Washington, DC 20460; telephone number: (202) 
564-7042; and email address: mia.marcia@epa.gov.

SUPPLEMENTARY INFORMATION:
    Public hearing. The EPA will hold a public hearing on the proposal. 
Details will be announced in a separate Federal Register document.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2017-0757. All documents in the docket are 
listed in Regulations.gov. Although listed, some information is not 
publicly available, e.g., Confidential Business Information (CBI) or 
other information whose disclosure is restricted by statute. Certain 
other material, such as copyrighted material, is not placed on the 
internet and will be publicly available only in hard copy. Publicly 
available docket materials are available either electronically in 
Regulations.gov or in hard copy at the EPA Docket Center, Room 3334, 
EPA 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-
2017-0757. 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, 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

[[Page 50245]]

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 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-2017-0757.
    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:

AEO Annual Energy Outlook
BLM Bureau of Land Management
BSER best system of emission reduction
CAA Clean Air Act
CAIT Climate Analysis Indicators Tool
CBI Confidential Business Information
CCAC Climate and Clean Air Coalition
CFR Code of Federal Regulations
CH4 methane
CO carbon monoxide
CO2 carbon dioxide
CO2 Eq. carbon dioxide equivalent
CVS closed vent system
EAV equivalent annualized value
EGU Electricity Generating Units
EIA Energy Information Administration
EPA Environmental Protection Agency
ESRL Earth System Research Laboratory
GAO Government Accountability Office
GHG greenhouse gases
GHGI greenhouse gas inventory
GHGRP Greenhouse Gas Reporting Program
HAP hazardous air pollutant(s)
H2S hydrogen sulfide
ICR Information Collection Request
IR infrared
kt kilotons
MMT Million Metric Tons
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NEI National Emissions Inventory
NEMS National Energy Modeling System
NGL natural gas liquids
NOAA National Oceanic and Atmospheric Administration
NODA Notice of Data Availability
NOX nitrogen oxides
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OGI optical gas imaging
OMB Office of Management and Budget
PE professional engineer
PHMSA Pipeline and Hazardous Materials Safety Administration
PM particulate matter
PM2.5 PM with a diameter of 2.5 micrometers or less
PM10 PM with a diameter of 10 micrometers or less
PRA Paperwork Reduction Act
PV present value
REC reduced emissions completion
RFA Regulatory Flexibility Act
RIA Regulatory Impact Analysis
SC-CH4 social cost of methane
SCF significant contribution finding
SIP state implementation plan
SO2 sulfur dioxide
tpy tons per year
TSD technical support document
UMRA Unfunded Mandates Reform Act
UNFCCC United Nations Framework Convention on Climate Change
U.S. United States
VOC volatile organic compounds
WRI World Resources Institute

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

I. Executive Summary
    A. Purpose and Summary of the Regulatory Action
    B. Costs and Benefits
II. General Information
    A. Does this action apply to me?
    B. What should I consider as I prepare my comments to the EPA?
    C. How do I obtain a copy of this document and other related 
information?
III. Background
    A. Oil and Natural Gas Industry and Its Emissions
    B. Statutory Background
    C. What is the regulatory history and litigation background 
regarding performance standards for the oil and natural gas 
industry?
    D. Other Notable Events
    E. Related State and Federal Regulatory Actions
IV. Summary and Rationale of Proposed Actions
    A. Revision of the Source Category To Remove Transmission and 
Storage Segment
    B. Rescission of the NSPS for Sources in Transmission and 
Storage Segment
    C. Status of Sources in Transmission and Storage Segment
    D. Rescission of the Applicability to Methane of the NSPS for 
Production and Processing Segments
V. Rationale for Alternative Proposal To Rescind the Methane 
Standards for All Sources in the Oil and Gas Source Category Without 
Revising the Source Category
    A. Alternative Proposed Action To Rescind the Methane Standards
    B. Rationale for Rescinding the Methane Standards
VI. Solicitation of Comment on Significant Contribution Finding for 
Methane
    A. Requirement for Pollutant-Specific Significant Contribution 
Finding
    B. Significant Contribution Finding in 2016 NSPS OOOOa Rule
    C. Criteria for Making a Significant Contribution Finding Under 
CAA Section 111
VII. Implications for Regulation of Existing Sources
    A. Existing Source Regulation Under CAA Section 111(d)
    B. Limited Impact of Lack of Regulation of Existing Oil and Gas 
Sources Under CAA Section 111(d)
VIII. Impacts of This Proposed Rule
    A. What are the air impacts?
    B. What are the energy impacts?
    C. What are the compliance costs?
    D. What are the economic and employment impacts?
    E. What are the benefits of the proposed standards?
IX. 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 Regulations and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    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. Executive Summary

A. Purpose and Summary of the Regulatory Action

    Since the inception of the CAA, with its aim to promote the 
``public health

[[Page 50246]]

and welfare and the productive capacity'' of the nation's population, 
the EPA has focused on air emissions from the oil and natural gas 
industry.1 2 For nearly 40 years, the EPA has issued 
regulations under CAA section 111 to limit emissions from the oil and 
natural gas industry, while accounting for costs and other factors as 
instructed by Congress in the statute.\3\ In this action, the EPA is 
recognizing its responsibilities under that section, performed in 
accordance with the statute and with national policy objectives. As 
such, the EPA here is proposing to amend its 2012 and 2016 rules 
affecting the industry, titled, respectively, ``Oil and Natural Gas 
Sector: New Source Performance Standards and National Emission 
Standards for Hazardous Air Pollutants Reviews; Final Rule'' (``2012 
NSPS OOOO'') \4\ and ``Oil and Natural Gas Sector: Emission Standards 
for New, Reconstructed, and Modified Sources; Final Rule'' (``2016 NSPS 
OOOOa'').\5\ Those rules established NSPS for VOC emissions from the 
oil and natural gas industry, and the 2016 rule also established NSPS 
for greenhouse gases (GHGs), in the form of limitations on methane, for 
that industry.\6\ The amendments that the EPA is proposing are intended 
to continue existing protections from emission sources within the 
regulated source category, while removing regulatory duplication.
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    \1\ 42 U.S.C. 7401(b)(1).
    \2\ 44 FR 49222 (August 21, 1979) (listing ``Crude Oil and 
Natural Gas Production'' under CAA section 111 as a source category 
subject to standards of performance).
    \3\ 50 FR 26122 (June 24, 1985) (promulgating NSPS that address 
certain VOC emissions); 50 FR 40158 (October 1, 1985) (promulgating 
NSPS that address certain sulfur dioxide (SO2) 
emissions).
    \4\ 77 FR 49490 (August 16, 2012).
    \5\ 81 FR 35824 (June 3, 2016).
    \6\ Docket ID No. EPA-HQ-OAR-2010-0505.
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    As directed by the President in March 2017, the EPA has reviewed 
the 2012 NSPS OOOO and 2016 NSPS OOOOa with attention to whether the 
rules ``unduly burden the development of domestic energy resources 
beyond the degree necessary to protect the public interest,'' and if 
so, appropriately ``suspend, revise, or rescind'' regulatory 
requirements.7 8 From this review, the EPA is now proposing 
to determine that some of the requirements under those rules are 
inappropriate because they affect sources that are not appropriately 
identified as part of the regulated source category, and some of the 
requirements under the 2016 NSPS OOOOa are unnecessary insofar as they 
impose redundant requirements. Accordingly, the EPA is acting to 
rescind those requirements while maintaining health and environmental 
protections from appropriately identified emission sources within the 
regulated source category.\9\
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    \7\ Executive Order 13783, ``Promoting Energy Independence and 
Economic Growth,'' section 1(c) (March 28, 2017).
    \8\ 82 FR 16331 (April 4, 2017) (notice of review of 2016 NSPS 
OOOOa pursuant to Executive Order 13783, signed by the EPA 
Administrator).
    \9\ We note that the EPA is addressing certain specific 
reconsideration issues--fugitive emissions requirements at well 
sites and compressor stations, well site pneumatic pump standards, 
and the requirements for certification of closed vent systems (CVS) 
by a professional engineer (PE)--in a separate proposal. See Docket 
ID Item No. EPA-HQ-OAR-2010-0505-7730 and 82 FR 25730.
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    Specifically, the EPA is co-proposing two potential actions: a 
primary proposal and an alternative proposal. The primary proposal 
contains two steps. In the first step, the EPA is proposing to revisit 
its 2012 and 2016 interpretations of, and its 2016 revision to, the 
regulated source category to cover sources in the transmission and 
storage segment, and to rescind the NSPS requirements applicable to 
those sources. Having reexamined the transmission and storage segment, 
the EPA has determined that the purported revision in 2016 of the pre-
existing source category (which the EPA now proposes to conclude was 
originally intended to include only the production and processing 
segments) was not appropriate. Because the transmission and storage 
segment constitutes a separate source category from the production and 
processing segments, the EPA could have listed it for regulation under 
CAA section 111(b) only by making a significant contribution and 
endangerment finding as required by the statue, which the EPA never 
did. Accordingly, under the first step of the primary proposal, the EPA 
proposes to rescind the standards applicable to sources in the 
transmission and storage segment of the oil and gas industry.
    As the second step, the EPA is proposing to rescind the methane 
requirements of the NSPS applicable to sources in the production and 
processing segments. The EPA proposed to conclude that those methane 
requirements are entirely redundant with the existing NSPS for VOC and, 
thus, establish no additional health protections. Indeed, due to the 
identical emission source control technologies for methane and VOC, the 
EPA, when establishing the 2016 NSPS OOOOa, found no need for any 
changes to the existing NSPS requirements for VOC when that rule 
explicitly examined regulation of methane emissions. Rescinding the 
applicability to methane emissions of the 2016 NSPS OOOOa requirements, 
while leaving the applicability to VOC emissions in place, will not 
affect the amount of methane emission reductions that those 
requirements will achieve.
    Under the alternative proposal, the EPA is proposing to rescind the 
methane requirements of the NSPS applicable to all oil and natural gas 
sources in the source category as it is currently constituted, without 
undoing the 2012 and 2016 interpretations or expansion of the source 
category to include sources in the transmission and storage segment. 
The rationale for rescinding the methane requirements under this 
alternative proposal is the same as noted immediately above, that is, 
that they are entirely redundant with the existing NSPS for VOC.
    Both the primary and alternative proposal rely on the EPA's 
previous interpretation of the requirement in CAA section 111(b)(1)(A) 
under which the EPA needs to make a finding that a source category 
``causes, or contributes significantly to, air pollution which may 
reasonably be anticipated to endanger public health or welfare'' when 
it lists the source category, but that thereafter, when it regulates 
pollutants emitted from the source category, it needs only a rational 
basis to do so. The EPA proposes to retain that interpretation of this 
statutory provision. However, in section VI.A of this preamble, the EPA 
takes comment on an alternative interpretation, under which the Agency 
is required to make the significant-contribution finding each time that 
it regulates a pollutant from the source category. In section VI.B of 
this preamble, the EPA takes comment on whether, under this alternative 
interpretation, it made a valid finding in the 2016 NSPS OOOOa that 
methane emissions from the Crude Oil and Natural Gas Production source 
category met this statutory standard. In section VI.C of this preamble, 
the EPA takes comment on its proposed identification of certain factors 
which would inform its judgment, should it make a new determination 
whether methane emissions from the source category meet this statutory 
standard.
    The EPA solicits public comment on all aspects of this proposal.

B. Costs and Benefits

    The EPA has projected the cost savings, emissions increases, and 
forgone benefits that may result from rescinding requirements from 
sources in the transmission and storage segment (i.e., the primary 
proposal). The projected cost savings and forgone

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benefits are presented in the regulatory impact analysis (RIA) 
supporting this proposal. The primary proposal action also rescinds 
methane requirements from sources in the production and processing 
segments and leaves the VOC regulations in place. As the methane 
control options are redundant with VOC control options, there are no 
expected cost or emissions effects from removing the methane 
requirements in the production and processing segments with respect to 
these sources. Similarly, there are no expected cost or emissions 
impacts under the alternative proposed option of rescinding the methane 
requirements for all affected sources for the same reason: Methane 
control options on all sources are redundant with VOC control options. 
The RIA estimates impacts for the analysis years 2019 through 2025. All 
monetized impacts of these amendments are presented in 2016 dollars. 
All sources in the transmission and storage segment that are affected 
by the 2016 NSPS OOOOa, starting at the promulgation of the 2016 NSPS 
OOOOa, are sources that are affected by this action.

II. General Information

A. Does this action apply to me?

    Categories and entities potentially affected by this action 
include:

                          Table 1--Industrial Source Categories Affected by This Action
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            Category              NAICS code \1\                  Examples of regulated entities
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Industry.......................          211120   Crude Petroleum Extraction.
                                         211130   Natural Gas Extraction.
                                         221210   Natural Gas Distribution.
                                         486110   Pipeline Distribution of Crude Oil.
                                         486210   Pipeline Transportation of Natural Gas.
Federal government.............  ...............  Not affected.
State/local/tribal government..  ...............  Not affected.
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\1\ North American Industry Classification System (NAICS).

    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that the EPA is now 
aware could potentially be affected by this action. Other types of 
entities not listed in the table could also be affected by this action. 
To determine whether your entity is affected by this action, you should 
carefully examine the applicability criteria found in the final rule. 
If you have questions regarding the applicability of this action to a 
particular entity, consult the person listed in the FOR FURTHER 
INFORMATION CONTACT section, your air permitting authority, or your EPA 
Regional representative listed in 40 CFR 60.4 (General Provisions).

B. What should I consider as I prepare my comments to the EPA?

    This action proposes to revise certain aspects of the 2012 NSPS 
OOOO and 2016 NSPS OOOOa rule. In this proposed action, we seek comment 
on only the specific proposals or comment solicitations in this 
proposed action. We do not seek comment on and we are not opening for 
reconsideration and review any other aspects of the NSPS in 40 CFR part 
60, subparts OOOO and OOOOa and related rulemakings at this time.

C. How do I obtain a copy of this document and other related 
information?

    In addition to being available in the docket, an electronic copy of 
the proposed action is available on the internet. Following signature 
by the Administrator, the EPA will post a copy of this proposed action 
at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry. 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. 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-2017-
0757).

III. Background

A. Oil and Natural Gas Industry and Its Emissions

    This section generally describes the structure of the oil and 
natural gas industry, the production, processing, as well as 
transmission and storage segments, and types of sources in each segment 
and the industry's emissions. This information is part of the basis of 
the regulatory approach that the EPA proposes here, which more 
accurately reflects the industry's differing segments and eliminates 
redundant and unnecessary regulatory burden, while maintaining 
protection for human health and the environment.
1. Oil and Natural Gas Industry--Structure
    For purposes of developing 40 CFR part 60, subparts OOOO and OOOOa, 
the EPA characterized the oil and natural gas industry operations as 
being generally composed of four so-called segments: (1) Extraction and 
production of crude oil and natural gas (``oil and natural gas 
production''), (2) natural gas processing, (3) natural gas transmission 
and storage, and (4) natural gas distribution.10 11 It 
should be noted that the EPA regulates oil refineries as a separate 
source category; accordingly, for purposes of this proposed rulemaking, 
for crude oil, the EPA's focus is on operations from the well to the 
point of custody transfer at a petroleum refinery, while for natural 
gas, the focus is on all operations from the well to the customer.
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    \10\ The EPA previously described an overview of the sector in 
section 2.0 of the 2011 Background Technical Support Document to 40 
CFR part 60, subpart OOOO, located at Docket ID Item No. EPA-HQ-OAR-
2010-0505-0045, and section 2.0 of the 2016 Background Technical 
Support Document to 40 CFR part 60, subpart OOOOa, located at Docket 
ID Item No. EPA-HQ-OAR-2010-0505-7631.
    \11\ While generally oil and natural gas production includes 
both onshore and offshore operations, 40 CFR part 60, subpart OOOOa 
addresses onshore operations.
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    The oil and natural gas production segment include the wells and 
all related processes used in the extraction, production, recovery, 
lifting, stabilization, and separation or treatment of oil and/or 
natural gas (including condensate). There are two basic types of wells, 
both of which are located on well ``pads'': Oil wells and natural gas 
wells. Oil wells comprise two types, oil wells that produce crude oil 
only and oil wells that produce both crude oil and natural gas 
(commonly referred to as ``associated'' gas). Production components 
located on the well pad may include, but are not limited to, wells and 
related casing heads; tubing heads; and ``Christmas tree'' piping, 
pumps, compressors,

[[Page 50248]]

heater treaters, separators, storage vessels, pneumatic devices, and 
dehydrators. Production operations include well drilling, completion, 
and recompletion processes, including all the portable non-self-
propelled apparatuses associated with those operations.\12\
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    \12\ The 2016 NSPS OOOOa rule defines reduced emissions 
completion (REC) to be a well completion following fracturing or 
refracturing where gas flowback that is otherwise vented is 
captured, cleaned, and routed to the gas flow line or collection 
system, re-injected into the well or another well, used as an on-
site fuel source, or used for other useful purpose that a purchased 
fuel or raw material would serve, with no direct release to the 
atmosphere.
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    Other sites that are part of the production segment include 
``centralized tank batteries,'' stand-alone sites where oil, 
condensate, produced water, and natural gas from several wells may be 
separated, stored, or treated. The production segment also includes the 
low pressure, small diameter, gathering pipelines and related 
components that collect and transport the oil, natural gas, and other 
materials and wastes from the wells to the refineries or natural gas 
processing plants.
    Of these products, crude oil and natural gas undergo successive, 
separate processing. Crude oil is separated from water and other 
impurities and transported to a refinery via truck, railcar, or 
pipeline. As noted above, the EPA treats oil refineries as a separate 
source category, accordingly, for present purposes, the oil component 
of the production segment ends at the point of custody transfer at the 
refinery.\13\
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    \13\ See 40 CFR part 60, subparts J and Ja and 40 CFR part 63, 
subparts CC and UUU.
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    The separated, unprocessed natural gas is commonly referred to as 
field gas and is composed of methane, natural gas liquids (NGL), and 
other impurities, such as water vapor, hydrogen sulfide 
(H2S), carbon dioxide (CO2), helium, and 
nitrogen. Ethane, propane, butane, isobutane, and pentane are all 
considered NGL and often are sold separately for a variety of different 
uses. Natural gas with high methane content is referred to as ``dry 
gas,'' while natural gas with significant amounts of ethane, propane, 
or butane is referred to as ``wet gas.'' Natural gas typically is sent 
to gas processing plants to separate NGLs for use as feedstock for 
petrochemical plants, burned for space heating and cooking, or blended 
into vehicle fuel. The composition of field gas varies across basins in 
the U.S.\14\ For example, the Appalachian region is predominately dry 
gas and northern mid-continent (North Dakota) region is primarily wet 
gas.
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    \14\ Memorandum to U.S. EPA from Eastern Research Group. 
``Natural Gas Composition.'' November 13, 2018. Docket ID No. EPA-
HQ-OAR-2017-0757.
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    The natural gas processing segment consists of separating certain 
hydrocarbons (HC) and fluids from the natural gas to produce ``pipeline 
quality'' dry natural gas. The degree and location of processing is 
dependent on factors such as the type of natural gas (e.g., wet or dry 
gas), market conditions, and company contract specifications. 
Typically, processing of natural gas begins in the field and continues 
as the gas is moved from the field through gathering and boosting 
stations to natural gas processing plants, where the complete 
processing of natural gas takes place. Natural gas processing 
operations separate and recover NGL or other non-methane gases and 
liquids from field gas through one or more of the following processes: 
Oil and condensate separation, water removal, separation of NGL, sulfur 
and CO2 removal, fractionation of NGL, and other processes, 
such as the capture of CO2 separated from natural gas 
streams for delivery outside the facility. In some ``dry gas'' areas, 
the field gas, with naturally higher methane content, may go from the 
well site directly into the transmission and storage segment without 
processing in a gas processing plant. However, there is still the need 
to remove liquids that naturally condense as the gas moves through the 
pipeline. Also, depending on the economics of NGLs as a product, there 
may be some amount of separation or extraction that occurs in 
transmission and storage using a ``dew point skid'' or what is commonly 
referred to as a ``straddle plant'' to meet specifications for the 
receiving pipeline. The EPA solicits comment on how commonly this type 
of processing occurs in the transmission and storage segment and 
whether we should--and how we might--differentiate a facility in which 
this type of processing occurs from a ``natural gas processing plant,'' 
as that term is currently defined in NSPS OOOOa. For example, the rule 
defines a ``natural gas processing plant'' to include a facility that 
extracts NGLs from field gas, where field gas is feedstock gas entering 
the natural gas processing plant. 40 CFR 60.5430a. If the field gas 
moves directly from the production segment into transmission and 
storage facilities, without passing through a natural gas processing 
plant, it would continue to be considered ``field gas,'' and if 
extraction of NGLs from such gas subsequently occurs in a transmission 
or storage facility, that facility would be considered a ``natural gas 
processing plant.''
    Once natural gas processing is complete, which the EPA understands 
generally to occur at natural gas processing plants, the resulting 
product is the pipeline quality natural gas that is ready for end use. 
The pipeline quality natural gas, which is comprised of 95 to 98 
percent methane,\15\ does not undergo any more phase changes after 
processing is complete; instead, this final product leaves processing 
operations and is transmitted to storage and/or distribution to the end 
user.
---------------------------------------------------------------------------

    \15\ https://www.epa.gov/natural-gas-star-program/overview-oil-and-natural-gas-industry.
---------------------------------------------------------------------------

    Pipelines in the natural gas transmission and storage segment can 
be interstate pipelines, which carry natural gas across state 
boundaries or intrastate pipelines, which transport the gas within a 
single state. Basic components of the two types of pipelines are the 
same, though interstate pipelines may be of a larger diameter and 
operated at a higher pressure. To ensure that the natural gas continues 
to flow through the pipeline, the natural gas must periodically be 
compressed, by increasing its pressure. Compressor stations perform 
this function and are usually placed at 40- to 100-mile intervals along 
the pipeline. At a compressor station, the natural gas enters the 
station, where it is compressed by reciprocating or centrifugal 
compressors.
    Another part of the transmission and storage segment are 
aboveground and underground natural gas storage facilities. Storage 
facilities hold natural gas for use during peak seasons. The main 
difference between underground and aboveground storage sites is that 
storage takes place in storage vessels constructed of non-earthen 
materials in aboveground storage. Underground storage of natural gas 
typically occurs in depleted natural gas or oil reservoirs and salt 
dome caverns. One purpose of this storage is for load balancing 
(equalizing the receipt and delivery of natural gas). At an underground 
storage site, typically other processes occur, including compression, 
dehydration, and flow measurement.
    The distribution segment is the final step in delivering natural 
gas to customers.\16\ The natural gas enters the distribution segment 
from delivery points located on interstate and intrastate transmission 
pipelines to business and household customers. The delivery point where 
the natural gas leaves the transmission and storage

[[Page 50249]]

segment and enters the distribution segment is a local distribution 
company's custody transfer station, commonly referred to as the 
``citygate.'' Natural gas distribution systems consist of thousands of 
miles of piping, including mains and service pipelines to the 
customers. If the distribution network is large, compressor stations 
may be necessary to maintain flow; however, these stations are 
typically smaller than transmission compressor stations. Distribution 
systems include metering stations, which allow distribution companies 
to monitor the natural gas as it flows through the system.
---------------------------------------------------------------------------

    \16\ The distribution segment is not regulated under 40 CFR part 
60, subpart OOOOa.
---------------------------------------------------------------------------

2. Oil & Natural Gas Industry--Emissions
    The oil and natural gas industry emit, in varying concentrations 
and amounts, a wide range of pollutants, including VOC, SO2, 
nitrogen oxides (NOX), H2S, carbon disulfide, and 
carbonyl sulfide. The oil and natural gas industry also emit GHG, such 
as methane and CO2. Emissions can occur in all segments of 
the natural gas industry. As natural gas moves through the system, 
emissions primarily result from intentional venting through normal 
operations, routine maintenance, unintentional fugitive emissions, and 
system upsets. Venting can occur through equipment design or 
operational practices, such as the continuous bleed of gas from 
pneumatic controllers (that control gas flows, levels, temperatures, 
and pressures in the equipment) or venting from well completions during 
production. In addition to vented emissions, emissions can occur from 
leaking equipment (also referred to as fugitive emissions) in all parts 
of the infrastructure, including major production and processing 
equipment (e.g., separators or storage vessels) and individual 
components (e.g., valves or connectors). Emissions from the crude oil 
portion of the industry result primarily from field production 
operations, such as venting of associated gas from oil wells, oil 
storage vessels, and production-related equipment such as gas 
dehydrators, pig traps, and pneumatic devices.
    Emissions of both methane and VOC occur through the same emission 
points and processes. The technologies available to capture and/or 
control both pollutants from these emission sources are the same, and 
in their function, those technologies do not select between VOC and 
methane emissions. The industry has profit incentives to capture and 
sell emissions of natural gas (and methane), and multiple states have 
programs in place to control assorted emissions from the industry.
    The next section provides estimated emissions of methane, VOC, and 
SO2 from oil and natural gas industry operation sources.
    a. Methane emissions in the U.S. and from the oil and natural gas 
industry. Official U.S. estimates of national level GHG emissions and 
sinks are developed by the EPA for the U.S. GHG Inventory (GHGI) to 
comply with commitments under the United Nations Framework Convention 
on Climate Change. The U.S. GHGI, which includes recent trends, is 
organized by industrial sectors. The oil and natural gas production, 
and natural gas processing and transmission sectors emit 29 percent of 
U.S. anthropogenic methane. Table 2 below presents total U.S. 
anthropogenic methane emissions for the years 1990, 2008, and 2017.
---------------------------------------------------------------------------

    \17\ Other sources include rice cultivation, forest land, 
stationary combustion, abandoned oil and gas wells, abandoned coal 
mines, mobile combustion, composting, and several sources emitting 
less than 1 MMT CO2 Eq. in 2017.

                                    Table 2--U.S. Methane Emissions by Sector
                          [Million metric ton carbon dioxide equivalent (MMT CO2 Eq.)]
----------------------------------------------------------------------------------------------------------------
                             Sector                                    1990            2008            2017
----------------------------------------------------------------------------------------------------------------
Oil and Natural Gas Production, and Natural Gas Processing and               191             195             190
 Transmission and Storage.......................................
    Oil and Natural Gas Production, and Natural Gas Processing..             134             163             158
    Oil and Natural Gas Transmission and Storage................              57              32              32
Landfills.......................................................             180             125             108
Enteric Fermentation............................................             164             174             175
Coal Mining.....................................................              96              76              56
Manure Management...............................................              37              58              62
Other Oil and Gas Sources.......................................              44              18              13
Wastewater Treatment............................................              15              15              14
Other Methane Sources \17\......................................              57              52              47
                                                                 -----------------------------------------------
    Total Methane Emissions.....................................             785             712             665
----------------------------------------------------------------------------------------------------------------
Emissions from the Inventory of United States Greenhouse Gas Emissions and Sinks: 1990-2017 (published April 11,
  2019), calculated using global warming potential (GWP) of 25.
Note: Totals may not sum due to rounding.

    Table 3 below presents total methane emissions from natural gas 
production through transmission and storage and petroleum production, 
for years 1990, 2008, and 2017, in MMT CO2 Eq. (or million 
metric tonnes carbon dioxide equivalent) of methane.

                     Table 3--U.S. Methane Emissions From Natural Gas and Petroleum Systems
                                                 [MMMT CO2 Eq.]
----------------------------------------------------------------------------------------------------------------
                             Sector                                    1990            2008            2017
----------------------------------------------------------------------------------------------------------------
Oil and Natural Gas Production and Natural Gas Processing and                191             195             190
 Transmission (Total)...........................................
Natural Gas Production..........................................              71             114             110
Natural Gas Processing..........................................              21              11              12
Natural Gas Transmission and Storage............................              57              32              32

[[Page 50250]]

 
Petroleum Production............................................              41              38              37
----------------------------------------------------------------------------------------------------------------
Emissions from the Inventory of United States Greenhouse Gas Emissions and Sinks: 1990-2017 (published April 11,
  2019), calculated using GWP of 25.
Note: Totals may not sum due to rounding.

    b. VOC and SO2 emissions in the U.S. and from the oil and natural 
gas industry. Official U.S. estimates of national level VOC and 
SO2 emissions are developed by the EPA for the National 
Emissions Inventory (NEI), for which states are required to submit 
information under 40 CFR part 51, subpart A. Data in the NEI may be 
organized by various data points, including sector, NAICS code, and 
Source Classification Code. The oil and natural gas sources emit 5.7 
and 1.8 percent of U.S. VOC and SO2, respectively. Tables 4 
and 5 below present total U.S. VOC and SO2 emissions by 
sector, respectively, for the year 2014, in kilotons (kt) (or thousand 
metric tons).

                  Table 4--U.S. VOC Emissions by Sector
                                  [kt]
------------------------------------------------------------------------
                         Sector                                2014
------------------------------------------------------------------------
Biogenics--Vegetation and Soil..........................          38,672
Oil and Natural Gas Production, and Natural Gas                    3,172
 Processing and Transmission............................
Fires--Wildfires........................................           2,466
Fires--Prescribed Fires.................................           1,980
Mobile--On-Road non-Diesel Light Duty Vehicles..........           1,965
Solvent--Consumer & Commercial Solvent Use..............           1,621
Mobile--Non-Road Equipment--Gasoline....................           1,536
Other VOC Sources \18\..................................           4,238
                                                         ---------------
    Total VOC Emissions.................................          55,651
------------------------------------------------------------------------
Emissions from the 2014 NEI, Version 2 (released February 2018).
Note: Totals may not sum due to rounding.


                  Table 5--U.S. SO2 Emissions by Sector
                                  [kt]
------------------------------------------------------------------------
                         Sector                                2014
------------------------------------------------------------------------
Fuel Comb--Electric Generation--Coal....................           3,155
Fuel Comb--Industrial Boilers, Internal Combustion                   335
 Engines--Coal..........................................
Mobile--Commercial Marine Vessels.......................             175
Industrial Processes--Not Elsewhere Classified..........             137
Industrial Processes--Chemical Manufacturing............             133
Oil and Natural Gas Production, and Natural Gas                       84
 Processing and Transmission............................
Other SO2 Sources\19\...................................             787
                                                         ---------------
Total SO2 Emissions.....................................           4,805
------------------------------------------------------------------------
Emissions from the 2014 NEI, Version 2 (released February 2018).
Note: Totals may not sum due to rounding.

    Table 6  below presents total VOC and SO2 emissions from 
oil and natural gas production through transmission and storage, for 
the year 2014, in kt (or thousand metric tons).
---------------------------------------------------------------------------

    \18\ Other sources include remaining sources emitting less than 
1,000 kt VOC in 2014.
    \19\ Other sources include remaining sources emitting less than 
100 kt SO2 in 2014.

   Table 6--U.S. VOC and SO2 Emissions From Natural Gas and Petroleum
                                 Systems
                                  [kt]
------------------------------------------------------------------------
                 Sector                         VOC             SO2
------------------------------------------------------------------------
Oil and Natural Gas Production and                 3,172              84
 Natural Gas Processing and Transmission
 (Total)................................
Oil and Natural Gas Production..........           3,143              48
Natural Gas Processing..................              14              36

[[Page 50251]]

 
Natural Gas Transmission and Storage....              16               1
------------------------------------------------------------------------
Emissions from the 2014 NEI, Version 2 (published February 2018), in kt
  (or thousand metric tons).
Note: Totals may not sum due to rounding.

B. Statutory Background

    CAA section 111 authorizes and directs the EPA to prescribe NSPS 
applicable to certain new stationary sources (which are defined by the 
statue to include newly constructed sources) and also existing sources 
that undergo ``modification'' within the meaning of CAA section 
111(a)(4)).\20\ As the first step to regulation, the CAA initially 
directed the EPA to publish by March 31, 1971, and ``from time to time 
thereafter [to] revise,'' a list of categories of stationary sources 
and to include on that list each category of stationary sources for 
which the Administrator has made a ``judgment'' that the emission of 
air pollutants from sources within such category ``causes, or 
contributes significantly to, air pollution which may reasonably be 
anticipated to endanger public health or welfare.'' \21\ The EPA has 
listed and regulated more than 60 stationary source categories under 
CAA section 111.\22\ The EPA listed the source category at issue here, 
``Crude Oil and Natural Gas Production'' in 1979.\23\
---------------------------------------------------------------------------

    \20\ CAA section 111(b)(1)(A).
    \21\ Id.
    \22\ See generally, 40 CFR part 60, subparts D-MMMM.
    \23\ 44 FR 49222 (August 21, 1979).
---------------------------------------------------------------------------

    Once the EPA has listed a source category, the EPA proposes and 
then promulgates ``standards of performance'' for new sources in the 
category, which includes sources that have yet to be constructed and 
those existing sources that undergo ``modification.'' \24\ In addition, 
the EPA's regulations provide that new sources also include an existing 
source that undertakes a reconstruction.
---------------------------------------------------------------------------

    \24\ CAA section 111(b)(1)(B).
---------------------------------------------------------------------------

    Under CAA section 111(b), the EPA must promulgate a ``standard of 
performance'' that new, modified, and reconstructed sources are to 
meet. CAA section 111(a)(1) defines a ``standard of performance'' as 
``a standard for emissions of air pollutants which reflects the degree 
of emission limitation achievable through the application of the best 
system of emission reduction (BSER) which (taking into account [cost 
and other factors]) the Administrator determines has been adequately 
demonstrated.'' This definition makes clear that the standard of 
performance must be based on ``the best system of emission reduction . 
. . adequately demonstrated'' (BSER).
    The U.S. Court of Appeals for the District of Columbia Circuit 
(D.C. Circuit) has had occasion over the years to speak to the 
definition of ``standard of performance'' and its component terms.\25\ 
By its terms, the definition of ``standard of performance'' under CAA 
section 111(a)(1) provides that the emission limits that the EPA 
promulgates must be ``achievable'' by application of a ``system of 
emission reduction'' that the EPA determines to be the ``best'' that is 
``adequately demonstrated,'' ``taking into account . . . cost . . . 
nonair quality health and environmental impact and energy 
requirements.''
---------------------------------------------------------------------------

    \25\ See 80 FR 64537 (discussing legislative history); Portland 
Cement Ass'n v. Ruckelshaus, 486 F.2d 375 (D.C. Cir. 1973); Essex 
Chemical Corp. v. Ruckelshaus, 486 F.2d 427, (D.C. Cir. 1973); 
Portland Cement Ass'n v. EPA, 665 F.3d 177 (D.C. Cir. 2011). See 
also Delaware v. EPA, 785 F.3d 1 (D.C. Cir. 2015).
---------------------------------------------------------------------------

    With respect to the cost factor, the D.C. Circuit has stated that 
the EPA may not adopt a standard the cost of which would be 
``unreasonable.'' \26\ The D.C. Circuit has indicated that the EPA has 
substantial discretion in its consideration of cost under CAA section 
111(a). Moreover, CAA section 111(a) does not provide specific 
direction regarding what metric or metrics to use in considering costs, 
again affording the EPA considerable discretion in choosing a means of 
cost consideration.\27\
---------------------------------------------------------------------------

    \26\ Sierra Club v. Costle, 657 F.2d 298, 343 (D.C. Cir. 1981). 
See ``Emission Guidelines for Greenhouse Gas Emissions From Existing 
Electric Utility Generating Units; Revisions to Emission Guideline 
Implementing Regulations; Revisions to New Source Review Program,'' 
Proposed Rule, 83 FR 44746, 44758 (August 31, 2018) (discussing D.C. 
Circuit caselaw).
    \27\ See, e.g., Husqvarna AB v. EPA, 254 F.3d 195, 200 (D.C. 
Cir. 2001) (where CAA section 213 does not mandate a specific method 
of cost analysis, the EPA may make a reasoned choice as to how to 
analyze costs).
---------------------------------------------------------------------------

C. What is the regulatory history and litigation background regarding 
performance standards for the oil and natural gas industry?

1. 1979 Listing of Source Category
    Subsequent to the enactment of the CAA of 1970, the EPA took action 
to develop standards of performance for new stationary sources as 
directed by Congress in CAA section 111. By 1977, the EPA had 
promulgated NSPS for a total of 27 source categories, while NSPS for an 
additional 25 source categories were then under development.\28\ 
However, in amending the CAA that year, Congress expressed 
dissatisfaction that the EPA's pace was too slow. Accordingly, the 1977 
CAA Amendments included a new subsection (f) in section 111, which 
specified a schedule for the EPA to list additional source categories 
under CAA section 111(b)(1)(A) and prioritize them for regulation under 
CAA section 111(b)(1)(B).
---------------------------------------------------------------------------

    \28\ See 44 FR 49222 (August 21, 1979).
---------------------------------------------------------------------------

    In 1979, as required by CAA section 111(f), the EPA published a 
list of source categories, which included ``Crude Oil and Natural Gas 
Production,'' for which the EPA would promulgate standards of 
performance under CAA section 111(b). See Priority List and Additions 
to the List of Categories of Stationary Sources, 44 FR 49222 (August 
21, 1979) (``1979 Priority List''). That list included, in the order of 
priority for promulgating standards, source categories that the EPA 
Administrator had determined, pursuant to CAA section 111(b)(1)(A), 
contribute significantly to air pollution that may reasonably be 
anticipated to endanger public health or welfare. See 44 FR 49223 
(August 21, 1979); see also 49 FR 2636-37 (January 20, 1984).
2. 1985 NSPS for VOC and SO2 Emissions From Natural Gas 
Processing Units
    On June 24, 1985 (50 FR 26122), the EPA promulgated NSPS for the 
source category that addressed VOC emissions from equipment leaks at 
onshore natural gas processing plants (40 CFR part 60, subpart KKK). On 
October 1, 1985 (50 FR 40158), the EPA promulgated NSPS

[[Page 50252]]

for the source category to regulate SO2 emissions from 
onshore natural gas processing plants (40 CFR part 60, subpart LLL).
3. 2012 NSPS OOOO Rule and Related NSPS Rules
    a. Regulatory action. In 2012, pursuant to its duty under CAA 
section 111(b)(1)(B) to review and, if appropriate, revise NSPS, the 
EPA published the final rule, ``Standards of Performance for Crude Oil 
and Natural Gas Production, Transmission and Distribution,'' 77 FR 
49490 (August 16, 2012) (40 CFR part 60, subpart OOOO) (``2012 NSPS 
OOOO''). This rule updated the SO2 standards for sweetening 
units and VOC standards for equipment leaks at onshore natural gas 
processing plants. In addition, it established VOC standards for 
several oil and natural gas-related operations emission sources not 
covered by 40 CFR part 60, subparts KKK and LLL, including natural gas 
well completions, centrifugal and reciprocating compressors, natural 
gas operated pneumatic controllers, and storage vessels. Using 
information available at the time, the EPA also evaluated methane 
emissions and reductions during the 2012 NSPS OOOO rulemaking as a 
potential co-benefit of regulating VOC emissions.
    In 2013, 2014, and 2015 the EPA amended the 2012 NSPS OOOO rule in 
order to address implementation of the standards. ``Oil and Natural Gas 
Sector: Reconsideration of Certain Provisions of New Source Performance 
Standards,'' 78 FR 58416 (September 23, 2013) (2013 NSPS OOOO) 
(concerning storage vessel implementation); ``Oil and Natural Gas 
Sector: Reconsideration of Additional Provisions of New Source 
Performance Standards,'' 79 FR 79018 (December 31, 2014) (``2014 NSPS 
OOOO'') (concerning well completion); ``Oil and Natural Gas Sector: 
Definitions of Low Pressure Gas Well and Storage Vessel,'' 80 FR 48262 
(August 12, 2015) (``2015 NSPS OOOO'') (concerning low pressure gas 
wells and storage vessels).
    The EPA received petitions for both judicial review and 
administrative reconsiderations for the 2012, 2013, and 2014 NSPS OOOO 
rules. The EPA denied reconsideration for some issues, see 
``Reconsideration of the Oil and Natural Gas Sector: New Source 
Performance Standards; Final Action,'' 81 FR 52778 (August 10, 2016), 
and, as noted below, granted reconsideration for other issues. All 
related litigation is currently stayed pending the reconsideration 
process.
4. 2016 NSPS OOOOa Rule and Related Amendments
    a. Regulatory action. On June 3, 2016, the EPA published a final 
rule titled ``Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources; Final Rule,'' at 81 FR 35824 (40 
CFR part 60, subpart OOOOa) (``2016 NSPS OOOOa'').29 30 The 
2016 NSPS OOOOa rule established NSPS for sources of GHG and VOC 
emissions for certain equipment, processes, and operations across the 
oil and natural gas industry. The 2016 NSPS OOOOa addresses the 
following emission sources:
---------------------------------------------------------------------------

    \29\ While the June 3, 2016, rulemaking also included final 
amendments to 40 CFR part 60, subpart OOOO, we are not proposing at 
this time to amend 40 CFR part 60, subpart OOOO.
    \30\ The 2016 NSPS OOOOa rule resulted from a series of 
directives from then President Obama targeted at reducing GHG, 
including methane: The President's Climate Action Plan (June 2013); 
the President's Climate Action Plan: Strategy to Reduce Methane 
Emissions (``Methane Strategy'') (March 2014); and the President's 
directive to address, and if appropriate, propose and set standards 
for methane and ozone-forming emissions from new and modified 
sources in the sector (January 2015).
---------------------------------------------------------------------------

     Sources that were unregulated under the 2012 NSPS OOOO 
(hydraulically fractured oil well completions, pneumatic pumps, and 
fugitive emissions from well sites and compressor stations);
     Sources that were regulated under the 2012 NSPS OOOO for 
VOC emissions, but not for GHG emissions (hydraulically fractured gas 
well completions and equipment leaks at natural gas processing plants); 
and
     Certain equipment that is used across the source category, 
for which the 2012 NSPS OOOO regulates emissions of VOC from only a 
subset (pneumatic controllers, centrifugal compressors, and 
reciprocating compressors), with the exception of compressors located 
at well sites.
    On March 12, 2018, the EPA finalized amendments of certain aspects 
of the 2016 NSPS OOOOa requirements for the collection of fugitive 
emission components at well sites and compressor stations, specifically 
(1) the requirement that components on a delay of repair must conduct 
repairs during unscheduled or emergency vent blowdowns, and (2) the 
monitoring survey requirements for well sites located on the Alaska 
North Slope.
    For further information on the 2016 NSPS OOOOa rule, see 81 FR 
35824 (June 3, 2016) and for further information on the 2018 NSPS OOOOa 
amendments, see 83 FR 10628 (March 12, 2018). The associated public 
docket for both actions is Docket ID No. EPA-HQ-OAR-2010-0505.
    b. Petitions to reconsider. Following promulgation of the 2016 NSPS 
OOOOa rule, the Administrator received five petitions for 
reconsideration of several provisions. Copies of the petitions are 
provided in Docket ID No. EPA-HQ-OAR-2010-0505.\31\ As noted below, the 
EPA has granted reconsideration of several issues in the 2016 NSPS 
OOOOa rule, proposed revisions to the final rule based on the 
reconsideration and addressed broad implementation issues that 
stakeholders had brought to the EPA's attention.
---------------------------------------------------------------------------

    \31\ See Docket ID Item Nos.: EPA-HQ-OAR-2010-0505-7682, EPA-HQ-
OAR-2010-0505-7683, EPA-HQ-OAR-2010-0505-7684, EPA-HQ-OAR-2010-0505-
7685, EPA-HQ-OAR-2010-0505-7686.
---------------------------------------------------------------------------

    c. Litigation. Several states and industry associations challenged 
the 2016 NSPS OOOOa rule in the D.C. Circuit, alleging, among other 
things, that the EPA acted arbitrarily and capriciously and in excess 
of statutory authority. See, e.g., West Virginia v. EPA, 16-1264, State 
Petitioners' Nonbinding Statement of the Issues to be Raised. These 
cases were consolidated. In addition, on January 4, 2017, the 
challenges to the 2016 NSPS OOOOa rule were consolidated with the 
challenges to the 2012 NSPS OOOO rule (as amended by the 2013 NSPS OOOO 
and 2014 NSPS OOOO rules), under American Petroleum Institute v. EPA, 
case No. 13-1108 (D.C. Cir.). ECF Dkt #1654072. On May 18, 2017, the 
D.C. Circuit issued an order granting a motion by the EPA to hold in 
abeyance the consolidated litigation over the 2012 NSPS OOOO rule (as 
amended by the 2013 NSPS OOOO and 2014 NSPS OOOO rules) and the 2016 
NSPS OOOOa rule, and requiring the EPA to file status reports every 60 
days informing the Court and parties regarding what action it has or 
will be taking regarding those rules. Id., ECF Dkt. #1675813.

D. Other Notable Events

    On March 28, 2017, newly elected President Donald Trump issued 
Executive Order 13783 titled ``Promoting Energy Independence and 
Economic Growth'' (hereinafter ``Executive Order''). The purpose of the 
Executive Order is to facilitate the development of domestic energy 
resources--including oil and gas--and to reduce unnecessary regulatory 
burdens associated with the development of those resources. 
Specifically, the Executive Order establishes the policy of the U.S. 
that executive departments and agencies ``immediately review existing 
regulations that potentially burden the

[[Page 50253]]

development or use of domestically produced energy resources and 
appropriately suspend, revise, or rescind those that unduly burden the 
development of domestic energy resources beyond the degree necessary to 
protect the public interest or otherwise comply with the law.'' Id., 
Section 1(c). The Executive Order specifically instructs the EPA, among 
other things, to ``review'' the 2016 NSPS OOOOa rule as well as ``any 
rules and guidance issued pursuant to it, for consistency with th[is] 
policy . . . .'' Id., Section 7. The Executive Order further provides 
that ``if appropriate, [the Agency] shall, as soon as practicable, 
suspend, revise, or rescind the guidance, or publish for notice and 
comment proposed rules suspending, revising, or rescinding those 
rules.'' Id.
    In accordance with the Executive Order, also on March 28, 2017, the 
EPA Administrator signed a Federal Register document announcing that 
the Agency is ``reviewing the 2016 Oil and Gas New Source Performance 
Standards (Rule), 81 FR 35824 (June 3, 2016), and, if appropriate, will 
initiate proceedings to suspend, revise, or rescind it.'' The EPA 
further explained that: ``If the EPA's review concludes that 
suspension, revision, or rescission of this Rule may be appropriate, 
the EPA's review will be followed by a rulemaking process that will be 
transparent, follow proper administrative procedures, include 
appropriate engagement with the public, employ sound science, and be 
firmly grounded in the law.'' Id., page 3. This notice was published in 
82 FR 16331 (April 4, 2017).
    On April 18, 2017, the EPA issued a letter granting reconsideration 
of the fugitive emissions requirements at well sites and compressor 
stations. On June 5, 2017, the EPA issued a notice granting 
reconsideration of additional issues, specifically the well site 
pneumatic pumps standards and the requirements for certification by a 
PE. See ``Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources; Grant of Reconsideration and 
Partial Stay,'' 82 FR 25730 (June 5, 2017).
    In addition, in the same June 5, 2017, document of action in which 
it granted reconsideration of additional issues, the EPA also issued, 
under CAA section 307(d)(7)(B), a 90-day partial stay of the 2016 NSPS 
OOOOa rule, pending the reconsiderations. Specifically, the EPA stayed 
the provisions for fugitive emissions requirements, well site pneumatic 
pump standards, and certification of CVS by a PE (40 CFR sections 
60.5393a(b) through (c), 60.5397a, 60.5410a(e)(2) through (5) and (j), 
60.5411a(d), 60.5415a(h), 60.5420a(b)(7), (8), and (12), and (c)(15) 
through (17)). 82 FR 25730. Environmental groups challenged this stay, 
and on July 3, 2017, the D.C. Circuit vacated the stay on grounds that 
it did not meet the CAA section 307(d)(7)(B) criteria. See Clean Air 
Council v. EPA, 862 F.3d 1 (D.C. Cir. 2017).
    On June 16, 2017, the EPA published a proposed stay of the same 
three requirements of the 2016 NSPS OOOOa rule for 2 years. ``Oil and 
Natural Gas Sector: Emission Standards for New, Reconstructed, and 
Modified Sources: Stay of Certain Requirements,'' 82 FR 27645 (June 16, 
2017).
    On November 8, 2017, the EPA issued a Notice of Data Availability 
(NODA) for the proposed 2-year stay of the 2016 NSPS OOOOa rule. In 
this NODA, the EPA provided, among other things, additional information 
on several topics raised by stakeholders and solicited comment on the 
information presented, including the legal authority to issue a stay 
and the technological, resource, and economic challenges with 
implementing the fugitive emissions requirements, well site pneumatic 
pump standards, and the requirements for certification of CVS by a PE. 
``Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources: Stay of Certain Requirements,'' 82 
FR 51788 (November 8, 2017). The EPA also solicited comment on other 
avenues to address these issues other than issuing a stay.
    As previously discussed, on March 12, 2018, the EPA finalized 
amendments of certain aspects of the requirements for the collection of 
fugitive emission components at well sites and compressor stations, 
specifically (1) the requirement that components on a delay of repair 
must conduct repairs during unscheduled or emergency vent blowdowns and 
(2) the monitoring survey requirements for well sites located on the 
Alaska North Slope. 83 FR 10628. These narrow amendments to the 2016 
NSPS OOOOa rule were in response to comments the EPA received on the 
proposed stays and NODA and address significant and immediate 
compliance concerns.
    On October 15, 2018, the EPA granted reconsideration of additional 
issues in the 2016 NSPS OOOOa rule, proposed revisions to that rule 
based on the reconsideration, and addressed broad implementation issues 
that stakeholders had brought to the EPA's attention. 83 FR 52056.

E. Related State and Federal Regulatory Actions

    Several states and federal agencies currently regulate the oil and 
natural gas industry. The scope of state requirements ranges from 
general reporting requirements to quantitative emissions limits and 
restrictions on venting and flaring. For example, Colorado requires 
that dehydrators, liquids unloading operations, and pneumatic 
controllers achieve specific emission reductions, in addition to 
regular monitoring of storage vessels and fugitive emissions. In Texas, 
well site requirements vary based on specific site-wide VOC emissions, 
but standard requirements exist for storage vessels, pneumatic 
controllers, and fugitive emissions. North Dakota has restrictions on 
venting and flaring. Ohio has general permit programs for well sites 
and compressor stations; the state also regulates dehydrators, engines, 
flares, fugitive emissions, and storage vessels at both well sites and 
compressor stations, in addition to requirements for compressors, truck 
loading, and pigging operations. Pennsylvania has a general permit 
program for compressor stations and a permit exemption program for well 
sites. The compressor station permit includes requirements for engines, 
compressors, storage vessels, fugitive emissions, and dehydrators. The 
permit exemption program includes requirements for well completions, 
engines, fugitive emissions, storage vessels, and flares. The EPA 
describes state fugitive emissions program requirements in the 
memorandum titled ``Equivalency of State Fugitive Emissions Programs 
for Well Sites and Compressor Stations to Proposed Standards at 40 CFR 
part 60, subpart OOOOa,'' located at Docket ID No. EPA-HQ-OAR-2017-
0483. Additional information can be found in a memorandum \32\ written 
by the Bureau of Land Management (BLM) in support of the ``Waste 
Prevention, Production Subject to Royalties, and Resource Conservation; 
Rescission or Revision of Certain Requirements,'' see 83 FR 7924.
---------------------------------------------------------------------------

    \32\ See Docket ID Item No. BLM-2018-0001-0004.
---------------------------------------------------------------------------

    In addition to states, certain federal agencies regulate the oil 
and natural gas industry. For example, on November 18, 2016, the BLM 
promulgated new regulations to reduce waste of natural gas from 
venting, flaring, and leaks during oil and natural gas production on 
onshore federal and Indian (other than Osage Tribe) leases.\33\ On 
September 28, 2018, the BLM finalized amendments to their 2016 rule in 
order to reduce

[[Page 50254]]

compliance burden and maintain consistency with BLM's existing 
statutory authorities.\34\ The BLM's revised 2018 rule discourages 
excessive venting and flaring by placing volume and time limits on 
royalty-free venting and flaring during production testing, 
emergencies, and downhole well maintenance and liquids unloading. 
Additionally, BLM's rule incentivizes the beneficial use of gas by 
making gas used for operations and production purposes royalty free. 
More detailed information can be found at BLM's website: https://www.blm.gov/programs/energy-and-minerals/oil-and-gas/operations-and-production/methane-and-waste-prevention-rule.
---------------------------------------------------------------------------

    \33\ 81 FR 83008 (November 18, 2016).
    \34\ 83 FR 49184.
---------------------------------------------------------------------------

    The Pipeline and Hazardous Materials Safety Administration (PHMSA) 
is responsible for regulating and ensuring the safe and secure movement 
of materials to industry and consumers by all modes of transportation, 
including pipelines. While PHMSA's regulations are focused on safety, 
there is likely a corresponding environmental co-benefit from their 
rules. For example, the PHMSA's Office of Pipeline Safety ensures 
safety in the design, construction, operation, maintenance, and 
incident response of the U.S.' approximately 2.6 million miles of 
natural gas and hazardous liquid transportation pipelines. When 
pipelines are maintained, the likelihood of environmental releases like 
leaks are reduced.\35\ More detailed information can be found at the 
PHMSA's website: https://www.phmsa.dot.gov/.
---------------------------------------------------------------------------

    \35\ See Final Report on Leak Detection Study to PHMSA. December 
10, 2012. https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/docs/technical-resources/pipeline/16691/leak-detection-study.pdf.
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IV. Summary and Rationale of Proposed Actions

    As directed by the President, the EPA has reviewed the 2012 NSPS 
OOOO and 2016 NSPS OOOOa with attention to whether the rules ``unduly 
burden the development of domestic energy resources beyond the degree 
necessary to protect the public interest'' and, if so, whether it is 
appropriate to ``suspend, revise, or rescind'' regulatory 
requirements.36 37 This proposal follows that review, and 
the EPA is proposing revisions to those requirements while maintaining 
health and environmental protections for emission sources within the 
regulated source category.\38\
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    \36\ Executive Order 13783, ``Promoting Energy Independence and 
Economic Growth,'' section 1(c) (March 28, 2017).
    \37\ 82 FR 16331 (April 4, 2017) (Notice of review of 2016 NSPS 
OOOOa pursuant to Executive Order 13783, signed by the EPA 
Administrator).
    \38\ We note that the EPA is addressing certain specific 
reconsideration issues--fugitive emissions requirements at well 
sites and compressor stations, well site pneumatic pump standards, 
and the requirements for certification of CVS by a PE--in a separate 
proposal. See Docket ID Item No. EPA-HQ-OAR-2010-0505-7730 and 82 FR 
25730.
---------------------------------------------------------------------------

    Specifically, the EPA is proposing to revise the source category to 
remove the transmission and storage segment entirely and rescind the 
NSPS requirements applicable to sources within the transmission and 
storage segment. This proposed action is based on the EPA's proposed 
determination that its 2012 and 2016 rulemakings that interpreted or 
expanded the source category to includes sources in the transmission 
and storage segment were improper in that regard. Further, the EPA is 
proposing to rescind the methane requirements of the NSPS applicable to 
sources within the production and processing segments because they are 
entirely redundant of the existing NSPS for VOC.\39\ Those 
requirements, thus, provide no additional health protections and are 
unnecessary. Indeed, due to the identical emissions profiles and source 
control technologies for methane and VOC, the EPA, when establishing 
the 2016 NSPS OOOOa to regulate methane, found no need for any changes 
to the existing NSPS requirements for VOC. Rescinding the requirements 
of the 2016 NSPS OOOOa applicable to methane emissions, while leaving 
in place the requirements applicable to VOC emissions, will not affect 
the amount of methane reductions that are achieved in the production 
and processing segments, but it will provide for greater clarity by 
simplifying the rule. Rescission of the requirements applicable to 
methane emissions will also obviate the need for the development of 
emission guidelines under CAA section 111(d) and 40 CFR part 60, 
subpart B to address methane emissions from existing sources within the 
crude oil and natural gas production industry.
---------------------------------------------------------------------------

    \39\ Section VI of this preamble takes comment on alternative 
questions of statutory interpretation and associated potential 
record determinations which, if the EPA were to adopt them, might 
provide an additional or alternative basis for both the primary and 
the alternative proposal.
---------------------------------------------------------------------------

    As an alternative to this first set of proposed actions, the EPA is 
proposing to rescind the methane requirements of the 2016 NSPS OOOOa 
applicable to all oil and natural gas sources without removing any 
sources from the source category.

A. Revision of the Source Category To Remove Transmission and Storage 
Segment

    Under CAA section 111(b)(1)(A), the EPA must ``publish . . . a list 
of categories of stationary sources, emissions from which, in the 
judgment of the Administrator, cause[ ], or contribute[ ] significantly 
to, air pollution which may reasonably be anticipated to endanger 
public health or welfare.'' Further, CAA section 111(b)(1)(A) directs 
that ``from time to time thereafter'' the EPA ``shall revise'' this 
``list'' of categories of stationary sources. Following the ``inclusion 
of a category of stationary sources in a list,'' the EPA then proposes 
and promulgates ``standards of performance for new sources within such 
category.'' CAA section 111(b)(1)(A). Thereafter, the EPA ``shall . . . 
review and, if appropriate, revise such standards.'' CAA section 
111(a)(1)(B).
    CAA section 111(b)(1)(A) does not include any specific criteria for 
determining the reasonable scope of a given ``category'' of 
``stationary sources'' beyond the requirement that the Administrator 
make a finding that, in his or her ``judgment,'' emissions from the 
``category of sources . . . cause[ ], or contribute[ ]significantly to, 
air pollution which may reasonably be anticipated to endanger public 
health or welfare.'' Accordingly, the EPA is afforded some measure of 
discretion in determining at the outset the scope of a source category.
    In 1978, the EPA published ``Priorities for New Source Performance 
Standards Under the Clean Air Act Amendments of 1977.'' \40\ The 
purpose of this document was to implement the requirements of CAA 
section 111(f) to develop and apply a methodology for identifying, 
establishing, and prioritizing the source categories that should be 
considered first for in-depth analysis prior to NSPS promulgation under 
CAA section 111. For purposes of the 1978 analysis, the EPA aggregated 
emissions from ``oil and gas production fields'' and ``natural gas 
processing'' as part of the ``Crude Oil and Natural Gas Production 
Plant'' source category. The EPA identified this aggregated source 
category as a source of HC and SO2 emissions. When the EPA 
finalized the priority list in 1979, it slightly revised the name of 
the source category as ``Crude Oil and Natural Gas Production.'' 49 FR 
49222 (August 21, 1979).
---------------------------------------------------------------------------

    \40\ Priorities for New Source Performance Standards Under the 
Clean Air Act Amendments of 1977. April 1978. EPA-450/3-78-019.

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[[Page 50255]]

    In 1985, the EPA promulgated two rulemakings establishing NSPS for 
the Crude Oil and Natural Gas Production source category. These were 40 
CFR part 60, subpart KKK--Standards of Performance for Equipment Leaks 
of VOC from Onshore Natural Gas Processing Plants (50 FR 26124, June 
23, 1985); and subpart LLL--Standards of Performance for SO2 
Emissions from Onshore Natural Gas Processing (50 FR 40160, October 1, 
1985). When it first proposed 40 CFR part 60, subpart KKK, the EPA 
noted that the ``category `Crude Oil and Natural Gas Production' ranks 
29th on the list of 59 source categories,'' and that the ``crude oil 
and natural gas production industry encompasses the operations of 
exploring for crude oil and natural gas products, removing them from 
beneath the earth's surface, and processing these products for 
distribution to petroleum refineries and gas pipelines.'' \41\ The EPA 
repeated that description of the identified source category when it 
first proposed 40 CFR part 60, subpart LLL, explaining that the ``crude 
oil and natural gas production industry encompasses not only processing 
of the natural gas (associated or not associated with crude oil) but 
operations of exploration, drilling, and subsequent removal of the gas 
from porous geologic formations beneath the earth's surface.'' \42\
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    \41\ 49 FR 2637 (January 20, 1984).
    \42\ 49 FR 2658 (January 20, 1984).
---------------------------------------------------------------------------

    In 2012, the EPA reviewed the VOC and SO2 standards and 
at the same time established new requirements for stationary sources of 
VOC emissions that had not been regulated in the 1985 rulemaking (e.g., 
well completions, pneumatic controllers, storage vessels, and 
compressors). 40 CFR part 60, subpart OOOO--Standards of Performance 
for Crude Oil and Natural Gas Production, Transmission and Distribution 
for which Construction, Modification or Reconstruction Commenced After 
August 23, 2011, and on or Before September 18, 2015, (77 FR 49542, 
August 16, 2012). In the preamble of the 2011 proposal for that 2012 
NSPS OOOO final rule, the EPA interpreted the 1979 listing as 
indicating that ``the currently listed Oil and Natural Gas source 
category covers all operations in this industry (i.e., production, 
processing, transmission, storage and distribution).'' 76 FR 52738, 
52745 (August 23, 2011). Further, the EPA stated that ``[t]o the extent 
there are oil and gas operations not covered by the currently listed 
Oil and Natural Gas source category. . . ., we hereby modify the 
category list to include all operations in the oil and natural gas 
sector.'' Id. at 52745. The stated basis for that proposed decision was 
that ``[s]ection 111(b) of the CAA gives the EPA the broad authority 
and discretion to list and establish NSPS for a category that, in the 
Administrator's judgment, causes or contributes significantly to air 
pollution which may reasonably be anticipated to endanger public health 
or welfare.'' Id. at 52745. No additional discussion of this listing 
position was provided in the 2011 proposal.
    In the 2012 final rulemaking, the EPA promulgated NSPS for emission 
sources in the production, processing, and transmission and storage 
segments, 77 FR 49490, 49492 (August 16, 2012), and stated that ``[t]he 
listed Crude Oil and Natural Gas Production source category covers, at 
a minimum, those operations for which we are establishing standards in 
this final rule.'' Id. at 49496. In responding to comments, the EPA 
took the position that it was not actually revising the source category 
to include emission sources in the transmission and storage segment, 
but rather, was interpreting the 1979 listing to be ``broad,'' and 
interpreting the 1985 rulemaking as ``view[ing] this source category 
listing very broadly,'' Id. at 49514, so that, in the EPA's view, the 
source category was already sufficiently broad to include that 
segment.\43\
---------------------------------------------------------------------------

    \43\ In the 2012 NSPS OOOO rulemaking, the EPA referred to the 
distribution segment of the oil and natural gas industry, which 
entails transporting natural gas to the end user, 76 FR 52738, 52745 
(August 23, 2011) (proposed rule); 49514, 77 FR 49493 (Table 2) 
(August 16, 2012) (final rule). However, in the 2016 NSPS OOOOa 
rule, the EPA clarified that the scope of the Oil and Natural Gas 
Production and Processing source category includes the transmission 
and storage segment, but not the distribution segment. In addition, 
the, EPA has never treated any sources in the distribution segment 
as subject to the requirements of NSPS OOOO or OOOOa.
---------------------------------------------------------------------------

    In 2016, the EPA promulgated new NSPS (40 CFR part 60, subpart 
OOOOa) for the Crude Oil and Natural Gas Production source category (81 
FR 35824, June 3, 2016). As the EPA did in the 2012 NSPS OOOO rule, the 
EPA took the position that the 1979 listing was broad enough to 
encompass the transmission and storage segment and that the 1985 
rulemakings confirmed that broad listing. The EPA stated that the 
inclusion of the transmission and storage segment into the original 
1979 source category was warranted because equipment and operations at 
production, processing, transmission and storage facilities are a 
sequence of functions that are interrelated and necessary for getting 
the recovered gas ready for distribution. Nevertheless, the EPA 
recognized that the scope of the prior listing may have had some 
ambiguity. Accordingly, ``as an alternative,'' the EPA finalized a 
revision of the category to broaden it, so that ``[a]s revised, the 
listed oil and natural gas source category includes oil and natural gas 
production, processing, transmission, and storage.'' (81 FR 35840).
    The EPA has reviewed the original 1979 listing of the Crude Oil and 
Natural Gas Production source category and the associated background 
materials and now proposes to find that its 2012 and 2016 
interpretation of the 1979 listing--i.e., that the 1979 listing 
included natural gas transmission and storage--was erroneous. The 
preamble accompanying the 1979 listing, which identified the source 
category as ``Crude Oil and Natural Gas Production,'' gave no 
indication that a source category ostensibly focused on ``production'' 
also included those sources associated with post-production operations 
such as transmission and storage. As explained in greater detail below, 
to the extent there was ambiguity, the issue was resolved in 1984, when 
the EPA, in proposing the first standards of performance for sources 
within the Crude Oil and Natural Gas Production source category (i.e., 
40 CFR part 60, subpart KKK), described the category as 
``encompass[ing] the operations of exploring for crude oil and natural 
gas products, removing them from beneath the earth's surface and 
processing these products for distribution to petroleum refineries and 
gas pipelines.'' \44\ This description, by its express terms, 
establishes that sources in the transmission and storage segment were 
not included in the Crude Oil and Natural Gas Production source 
category as listed in 1979. Therefore, the EPA is proposing to disavow 
its erroneous interpretation from 2012 and 2016, and instead propose 
that the source category does not include natural gas transmission and 
storage. Following are details of our rationale for this action.
---------------------------------------------------------------------------

    \44\ 49 FR 2637; see also 49 FR 2658.
---------------------------------------------------------------------------

    As noted above, the 1978 ``Priorities for New Source Performance 
Standards Under the Clean Air Act Amendments of 1977'' analysis 
aggregated the emissions from ``oil and gas production fields'' and 
``natural gas processing'' as part of what was then labeled as the 
``Crude Oil and Natural Gas Production Plants'' source category. This 
aggregated source category was identified as a source of HC and 
SO2 emissions. The EPA listed the ``Stationary Pipeline 
Compressor Engines'' source category separately, which included 
emissions specific to engines used at compressor stations (i.e., 
NOX, SO2 and carbon

[[Page 50256]]

monoxide (CO)). EPA-450/3-78-019 (April 1978).
    The revised priority list that the EPA promulgated in 1979 and its 
associated support document, ``Revised Prioritized List of Source 
Categories for Promulgation,'' \45\ included the aggregated ``Crude Oil 
and Natural Gas Production Plants'' source category. The support 
document also included a separate study of ``stationary pipeline 
compressor engines'' emissions. The record makes clear that, at the 
time, the EPA was distinguishing between oil and natural gas production 
plants and natural gas processing on the one hand, and stationary 
pipeline compressor engines on the other, and that it intended to 
promulgate separate standards for HC and SO2 emissions from 
those two source categories. EPA-450/3-79-023 (March 1979). The record 
for the 1979 action indicates that, at the time, the EPA clearly 
considered the ``Crude Oil and Natural Gas Production'' source category 
to include but be limited to production and processing operations. In 
addition, the record makes clear that the EPA also considered 
stationary pipeline compressor engines to be part of a separate source 
category.\46\ Other parts of the record indicate that the EPA intended 
to promulgate standards separately for HC and SO2 emissions 
from those two sets of sources. EPA-450/3-79-023 (March 1979). In 
contrast, the record does not specifically address the transmission and 
storage segment.
---------------------------------------------------------------------------

    \45\ U.S. EPA. ``Revised Prioritized List of Source Categories 
for NSPS Promulgation.'' March 1979. EPA-450/3-79-023.
    \46\ The EPA promulgated NSPS for stationary spark ignition 
internal compressor engines under the ``Standards of Performance for 
Stationary Spark Ignition Internal Combustion Engines and National 
Emission Standards for Hazardous Air Pollutants for Reciprocating 
Internal Combustion Engines.'' (40 CFR part 60, subpart JJJJ; 73 FR 
3568, 3569, January 18, 2008). These standards applied to engines 
located at compressor stations at natural gas transmission and 
storage facilities, as well as engines located in other industry 
sectors.
---------------------------------------------------------------------------

    As has already been noted, in 1984-85, the EPA developed the first 
two NSPS for the source category (40 CFR part 60, subparts KKK and LLL) 
by establishing standards to address VOC and SO2 emissions 
for sources in the production and processing segments alone, and in so 
doing, indicated that it considered the scope of the source category to 
be limited to those segments. Specifically, the EPA promulgated 
standards at 40 CFR part 60, subpart KKK for onshore natural gas 
processing plants in 1985, which were the first standards promulgated 
for the source category. In the 1984 proposal preamble, the EPA 
clarified the scope of the source category as follows:

    The crude oil and natural gas production industry encompasses 
the operations of exploring for crude oil and natural gas products, 
drilling for these products, removing them from beneath the earth's 
surface, and processing these products from oil and gas fields for 
distribution to petroleum refineries and gas pipelines.

49 FR 2636.
    Thus, in the sentence just quoted, the EPA explicitly defined the 
source category as encompassing the natural gas operations up to the 
point of distribution to gas pipelines, that is, up to the storage and 
transmission segment, and in that manner, indicated that this segment 
was not included in the source category. (Similarly, in the same 
sentence, the EPA defined the scope of the source category as 
encompassing oil operations up to the point of distribution to 
petroleum refineries, which are a separate source category.) In this 
manner, the EPA indicated that the Crude Oil and Natural Gas Production 
source category includes operations from well sites (exploration, 
drilling, and removal) and natural gas processing plants (processing). 
While gathering and boosting compressor stations were not specified, it 
is reasonable to conclude that they are also included because they are 
located between two covered sites, the well site and the processing 
plant. However, to reiterate, subsequent operations, such as 
transmission, storage, and distribution were not included. Thus, the 
EPA is now proposing to find that its earlier view that the original 
listing in 1979 of the Crude Oil and Natural Gas Production source 
category already included the transmission and storage segment was in 
error, as the record of the 1979 listing action, and subsequent 
rulemaking actions by the EPA, described above, make clear.
    As noted above, we had stated in the 2016 NSPS OOOOa rule our view 
that the ``1979 listing of [the Crude Oil and Natural Gas Production] 
source category provides sufficient authority for this action,'' but we 
then added that, ``to the extent that there is ambiguity in the prior 
listing, the EPA hereby finalizes, as an alternative, its proposed 
revision of the category listing to broadly include the oil and natural 
gas industry.'' \47\ ``As revised,'' we went on to say, ``the listed 
oil and natural gas category includes oil and natural gas production, 
processing, transmission, and storage.'' \48\ As discussed next, the 
EPA is further proposing to find that this ``alternative'' approach--
i.e., ``revising'' the previously-established Crude Oil and Natural Gas 
Production source category to include sources within the storage and 
transmission segment--was in error.
---------------------------------------------------------------------------

    \47\ 81 FR 35833.
    \48\ Id. (footnote omitted).
---------------------------------------------------------------------------

    While CAA section 111(b)(1)(A) and (B), respectively direct the EPA 
to ``revise,'' where warranted, both the ``list of source categories'' 
and the ``standards of performance'' that the EPA has promulgated, 
nothing in CAA section 111 expressly authorizes or directs the EPA to 
``revise'' a ``source category,'' by altering its scope, once the EPA 
has listed that source category. However, the EPA has inherent 
authority to reconsider, repeal, or revise past decisions to the extent 
permitted by law so long as the Agency provides a reasoned explanation. 
See Motor Vehicle Manufacturers Association of the United States v. 
State Farm Mutual Automobile Insurance Co., 463 US 29, 56-57 (1983) 
(``an agency changing its course must supply a reasoned analysis,'' 
quoting Greater Boston Television Corp. v. FCC, 143 F.2d 841, 842 (D.C. 
Cir.)). The CAA complements the EPA's inherent authority to reconsider 
prior rulemakings by providing the Agency with broad authority to 
prescribe regulations as necessary. See 42 U.S.C. 7601(a). See Clean 
Air Council v. Pruitt, 862 F.3d 1, 8-9 (D.C. Cir. 2017) (``[a]gencies 
obviously have broad discretion to reconsider a regulation at any 
time''). Even so, the EPA proposes that the authority to revise the 
scope of a source category must be exercised only within reasonable 
boundaries and cannot be employed in such a way as to result in an 
unreasonable expansion of an existing source category, i.e., one that 
purports to expand a source category to cover a new set of sources that 
are sufficiently unrelated to the sources in the pre-existing category 
that they constitute a separate source category for which the EPA is 
required to make a new contribute-significantly-and-endangerment 
finding as a prerequisite to regulating them. Otherwise, expanding the 
source category by including new sources could be used to circumvent 
that requirement. The EPA proposes to conclude that the 2016 expansion 
of the source category to include sources in the transmission and 
storage segment did, in fact, exceed the reasonable boundaries of its 
authority to revise source categories.
    In the 2016 NSPS OOOOa rule, the EPA purported to ``support'' its 
``revision'' of the source category by making the ``requisite finding 
under section 111(b)(1) that, in the Administrator's judgment, this 
source

[[Page 50257]]

category, as defined above, contributes significantly to air pollution 
which may reasonably be anticipated to endanger public health or 
welfare.'' \49\ The EPA is now proposing to find that this approach was 
erroneous.
---------------------------------------------------------------------------

    \49\ 81 FR 35833 (emphasis added).
---------------------------------------------------------------------------

    Specifically, we are proposing that the EPA was required to make a 
finding that the transmission and storage segment in and of itself 
``contributes significantly to air pollution which may reasonably be 
anticipated to endanger public health or welfare,'' not simply that the 
source category, ``as defined above''--i.e., defined to include ``oil 
and natural gas production, processing, transmission, and storage'' 
\50\--``contributes significantly.'' Nowhere in the course of 
promulgating the 2016 NSPS OOOOa rule did the EPA make a finding that 
sources in the transmission and storage segment, in themselves, 
``contribute[ ] significantly to air pollution which may reasonably be 
anticipated to endanger public health or welfare.'' The EPA avoided 
making such a finding by purporting to have ``revised'' the source 
category by including that transmission and storage segment and then 
proceeding to find that the expanded source category ``contributes 
significantly.'' \51\
---------------------------------------------------------------------------

    \50\ Id.
    \51\ See 80 FR 35837-35840 (explaining ``how GHG, VOC and 
SO2 emissions'' from the source category as revised to 
include the oil and natural gas production, processing, 
transmission, and storage segments, and not the transmission and 
storage segment itself, ``are `air pollution' that may reasonably be 
anticipated to endanger public health and welfare.'').
---------------------------------------------------------------------------

    This approach, the EPA now proposes to find, was not appropriate. 
Had the EPA chosen to revise the source category list to include the 
``transmission and storage'' segment as a separate source category, it 
could have done so only after making a finding that emissions from 
sources within that source category ``cause[ ], or contribute 
significantly to air pollution which may reasonably be anticipated to 
endanger public health or welfare.'' Thus, if transmission and storage 
sources are sufficiently distinct from production and processing 
sources such that it would not be appropriate to include them in the 
Crude Oil and Natural Gas source category via revising of that source 
category, then the EPA could promulgate NSPS for them only if it first 
listed them as a separate source category, a step that the EPA has not 
taken.\52\
---------------------------------------------------------------------------

    \52\ In prior actions to expand a previously listed source 
category to include additional sources when the Agency considers the 
newly added sources to be logically connected to the sources already 
in the source category, the EPA has taken different approaches, 
ranging from making a significant contribution finding for the newly 
added sources, making such a finding for the newly expanded source 
category, and not making such a finding at all. Compare ``Standards 
of Performance for New Stationary Sources; Priority List--Final 
Rule,'' 47 FR 31875, 31876 (July 23, 1982), ``Standards of 
Performance for New Stationary Sources; Priority List--Proposed 
Amendment,'' 45 FR 76427, 26427-28 (November 18, 1980) (expanding 
the ``asphalt roofing source category'' to include ``asphalt blowing 
stills and storage tanks at asphalt processing facilities and 
petroleum refineries;'' explaining that ``[i]t is . . . reasonable 
to treat the asphalt processing and roofing manufacture industry as 
a single category of sources'' because the processing and refinery 
sources are sites for ``initial steps in the preparation of asphalt 
for roofing manufacture'' and ``[t]he emissions, processes, and 
applicable controls for blowing stills and asphalt storage tanks at 
oil refineries and asphalt processing plants are the same as those 
at asphalt roofing plants;'' determining that the added sources 
``contribute significantly to air pollution which may reasonably be 
anticipated to endanger public health or welfare'') with ``Standards 
of Performance for New Stationary Sources; Industrial-Commercial-
Institutional Steam Generating Units--Final Rule,'' 51 FR 42794, 
42794-95 (November 25, 1986) (expanding the source category of 
``industrial fossil fuel-fired steam generators'' to ``cover all 
steam generators, including both fossil and nonfossil fuel-fired 
steam generators, as well as steam generators used in industrial, 
commercial, and institutional applications;'' explaining that 
``fossil and nonfossil fuel-fired industrial, commercial, and 
institutional steam generating units should be classified together 
as one source category . . . [because they] emit similar pollutants, 
fire the same fuels, and may employ the same emission control 
techniques [and] [t]heir impacts on human health are similar;'' 
determining that the source category as expanded ``is a significant 
contributor and an appropriate source category for regulation;'' and 
adding that ``[t]here is no requirement that each subcategory of a 
listed category . . . also be significant contributors'') and 
``Standards of Performance for New Stationary Sources, Volatile 
Organic Liquid Storage Vessels (Including Petroleum Liquid Storage 
Vessels) Constructed After July 23, 1984--Proposed Rule,'' 49 FR 
29698, 29700 (July 23, 1984), ``Standards of Performance for New 
Stationary Sources: Volatile Organic Liquid Storage Vessels 
(Including Petroleum Liquid Storage Vessels)--Final Rule,'' 52 FR 
11420, 11420 (April 8, 1987) (expanding the ``synthetic organic 
chemical manufacturing industry'' (SOCMI) source category to include 
``storage vessels emitting VOC's located at plants other than SOCMI 
plants, such as liquid bulk storage terminals;'' explaining that 
those facilities ``store the same or similar liquids as those at 
SOCMI plants and . . . can be controlled with the same 
effectiveness, the same costs . . . and the same control technology 
as storage vessels located at SOCMI plants;'' not making any 
determination concerning significant contribution).
---------------------------------------------------------------------------

    The EPA proposes to determine that transmission and storage sources 
are, in fact, sufficiently distinct from production and processing 
sources that the EPA erred when, in the 2016 NSPS OOOOa rule, it 
purported to revise the source category to include sources in the 
transmission and storage segment. Specifically, the EPA proposes to 
determine that its determination in the 2016 NSPS OOOOa rule that 
equipment and operations at production, processing, and transmission 
and storage facilities are a sequence of functions that are 
interrelated and necessary for getting the recovered gas ready for 
distribution, was unreasonable. We now propose that the transmission 
and storage operations are distinct from production and processing 
operations because the natural gas that enters the transmission and 
storage segment has different composition and characteristics than the 
natural gas that enters the production and processing segments.
    The primary operations of the production and processing segments 
are the exploration of crude oil and natural gas products beneath the 
earth's surface, drilling wells that are used to extract these 
products, and processing the crude oil and field gas for distribution 
to petroleum refineries and gas pipelines. As stated previously in this 
section, the EPA described this source category's operations similarly 
when proposing 40 CFR part 60, subpart KKK in 1984. 49 FR 2637. The 
primary purpose of these segments is to remove impurities from the 
extracted product. At a well site (production segment), crude oil and 
natural gas are extracted from the ground. Some processing can take 
place at the well site, such as the physical separation of gas, 
production fluids, and condensate. The separated gas (``field gas'') is 
then sent through gathering pipelines to the natural gas processing 
plant (processing segment). At the processing plant, the field gas is 
converted to sales gas or pipeline quality gas. This involves several 
steps including the extraction of natural gas liquids (e.g., a mixture 
of propane, butane, pentane) from the field gas, the fractionation of 
these natural gas liquids into individual products (e.g., liquid 
propane), or both extraction and fractionation. The final natural gas 
that exits the processing plant is sales gas, which is predominantly 
methane, as discussed above. In these segments, the field gas has 
physically changed such that it is a usable product.
    Analysis of the composition of gas on a nationwide basis in the 
various industry segments confirms the different character of the 
segments. In 2011 and subsequently in 2018, the EPA conducted an 
analysis of the composition, expressed in percent volume, of natural 
gas based on the methane, VOC, and hazardous air pollutant (HAP) 
content across the various industry segments.53 54 For

[[Page 50258]]

example, in 2011, the nationwide composition for the production 
segment, which included wells and unprocessed natural gas, consisted of 
approximately 83 percent methane, 4 percent VOC, and less than 1 
percent HAP. In contrast, the transmission segment, which included 
pipeline and sales gas (i.e., post processing), consisted of 
approximately 93 percent methane, 1 percent VOC, and less than 0.01 
percent HAP. In 2018, the EPA reviewed new studies available and found 
similar results. The nationwide composition for the production segment 
consisted of approximately 88 percent methane and 4 percent VOC. In 
addition, the EPA determined the data was insufficient to include HAP 
in the final analysis. Limited updated natural gas composition data 
were available for the transmission and storage segment. These 
differences in the gas composition demonstrate that the emissions 
profile is different following gas processing; however, the EPA 
recognizes that these numbers are nationwide and that variations can 
occur from basin-to-basin within each segment. The fact that the 
original listing was specific to VOC and SO2 emissions and 
that emissions of these pollutants are lower downstream of the natural 
gas processing plant further support our interpretation that the 1979 
listing included only the production and processing segments.
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    \53\ Memorandum to Bruce Moore, U.S. EPA from Heather Brown, EC/
R. ``Composition of Natural Gas for use in the Oil and Natural Gas 
Sector Rulemaking.'' July 2011. Docket ID Item No. EPA-HQ-OAR-2010-
0505-0084.
    \54\ Memorandum to U.S. EPA from Eastern Research Group. 
``Natural Gas Composition.'' November 13, 2018. Docket ID No. EPA-
HQ-OAR-2017-0757.
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    The operations of the transmission and storage segment differ from 
production and processing because in the former, the natural gas does 
not undergo changes in composition, except for some limited removal of 
liquids that condensed during the temperature and pressure changes as 
the gas moves through the pipeline. Therefore, the natural gas that 
enters the transmission and storage segment has approximately the same 
composition and characteristics as the natural gas that leaves the 
segment for distribution. The segment includes natural gas transmission 
compressor stations, whose primary operation is to move the natural gas 
through transmission pipelines by increasing the pressure. Dehydration, 
which can also occur at compressor stations, is a secondary operation 
used when the natural gas has collected water during transmission. At 
storage facilities, natural gas is injected into underground storage 
for use during peak seasons.\55\ When demand increases, the natural gas 
is extracted from the underground storage, dehydrated to remove water 
that has entered during storage, compressed, and moved through 
distribution pipelines. It is the EPA's understanding that processing 
of field gas generally occurs within the production and processing 
segments. Operators within the transmission and storage segment 
typically do not operate within the production and processing segments 
and vice-versa.
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    \55\ Storage can also take place in above ground storage 
vessels; however, it is our understanding that these are more 
commonly used after the city gate, which has not been included in 
the source category at any point.
---------------------------------------------------------------------------

    These distinct differences in the operations, the physical 
transformation of the field gas to sales gas, and the physical movement 
of sales gas through pipelines establish that two separate categories 
are necessary. This distinction is similar to the distinction the EPA 
has made between other source categories with segments that handle the 
production and processing of a material and subsequent transport of the 
product. One example is the petroleum industry. In that industry, crude 
oil is produced through the extraction of material at well sites from 
beneath the earth's surface. Crude oil is then transferred to 
refineries where it undergoes chemical and physical changes that result 
in various formulations of gasoline. The refined gasoline is 
transmitted by pipeline, ship, barge, or rail to bulk gasoline 
terminals that store the product in large above ground tanks until it 
is loaded for transport to distribution networks. The segments of the 
petroleum industry are also demarcated by product composition, the 
physical, and in the case of the petroleum industry, chemical 
transformation of crude oil to refined gasoline products such as 
gasoline, jet aircraft fuels, diesel fuel, motor oil, kerosene, 
asphalt, and sulfur. Production facilities,\56\ refineries,\57\ and 
bulk gasoline terminals \58\ all have operational differences, and the 
EPA placed them in three different source categories. Those operational 
differences are similar to the operational differences between the 
production and processing segments and the transmission and storage 
segment at issue in this proposal.
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    \56\ U.S. EPA. ``Revised Prioritized List of Source Categories 
for NSPS Promulgation.'' March 1979. EPA-450/3-79-023.
    \57\ 38 FR 15406 (May 4, 1973); 39 FR 9315 (March 8, 1974).
    \58\ 45 FR 83126 (December 12, 1980); 48 FR 37578 (August 18, 
1983).
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    It should be noted that in the 2016 NSPS OOOOa rule, the EPA 
justified including the transmission and storage segment in the Crude 
Oil and Natural Gas source category partly because some similar 
equipment (e.g., storage vessels, pneumatic pumps, compressors) is used 
across the industry. While that is true, the differences in the 
operations of, and the emission profiles of, the different segments are 
more significant and support our proposal to exclude the transmission 
and storage segment from the source category. A review of 2016 NSPS 
OOOOa compliance reports from sources in the EPA Regions (3, 6, 8, 9, 
and 10) with the greatest oil and natural gas activity indicates that 
there were no storage vessels emitting more than 6 tons per year (tpy) 
VOC reported in the transmission and storage segment.\59\ This supports 
our understanding that VOC emissions are lower in the transmission and 
storage segment and supports our understanding that any gas processing 
that occurs in the transmission and storage segment generally is 
limited to removing liquids that condensed during the temperature and 
pressure changes as the gas moves through the pipeline.
---------------------------------------------------------------------------

    \59\ These reports have since been made available for public 
viewing at https://www.foiaonline.gov/foiaonline/action/public/submissionDetails?trackingNumber=EPA-HQ-2018-001886&type=request.
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    In summary, the EPA has not identified information from the 
original source category listing that indicates the transmission and 
storage segment was included in the Crude Oil and Natural Gas 
Production source category. In fact, in 1985, the date of the first 
standards that the EPA promulgated for the source category, the EPA 
clearly indicated that the source category was limited (and should be 
limited) to the production and processing segments. Further, there are 
distinct differences in operations and differences in the emissions 
profiles between the production and processing segments and the 
transmission and storage segment. We are, therefore, proposing to 
exclude transmission and storage sources from the Crude Oil and Natural 
Gas Production source category.

B. Rescission of the NSPS for Sources in Transmission and Storage 
Segment

    A prerequisite for the EPA to promulgate an NSPS applicable to new 
sources is that the new sources must be in a source category that the 
EPA has listed under CAA section 111(b)(1). For the reasons stated in 
section IV.A immediately above, the EPA is proposing to rescind as 
improper the 2012 and 2016 rules' interpretations or extension of the 
source category to encompass sources in the transmission and storage 
segment. Under the proposed rescission, transmission and storage 
sources would not be contained

[[Page 50259]]

within a listed source category. Accordingly, the promulgation of NSPS 
for transmission and storage sources was contrary to law, and as a 
result, the EPA is also proposing to rescind the NSPS in OOOO and OOOOa 
for emission sources in the transmission and storage segment. 
Specifically, we are proposing to rescind the requirements for 
compressor affected facilities located downstream of the natural gas 
processing plant; pneumatic controllers located downstream of the 
natural gas processing plant; storage vessel affected facilities 
located downstream of the natural gas processing plant; and the 
affected facility that is the collection of fugitive emission 
components located at a compressor station.

C. Status of Sources in Transmission and Storage Segment

    If this proposal is finalized, the transmission and storage segment 
will revert to the status of a segment of the oil and natural gas 
industry not listed as a source category under CAA section 111(b)(1)(A) 
and, thus, will not be subject to regulation under CAA section 111(b) 
(for new sources) or CAA section 111(d) (for existing sources that emit 
certain air pollutants). The emission sources in the transmission and 
storage segment will be in the same position as emissions sources in 
other industries that the EPA has not listed as a source category under 
CAA section 111(b)(1)(A).
    In the future, the EPA may evaluate these emissions more closely 
and determine whether the transmission and storage segment should be 
listed as a source category under CAA section 111(b)(1)(A).\60\
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    \60\ Methane emissions from the transmission and storage segment 
are 32 MMT CO2 Eq. (1,295 kt methane) per the Inventory 
of United States Greenhouse Gas Emissions and Sinks: 1990-2017 
(published April 11, 2019), which amounts to 5 percent of United 
States methane emissions and 0.5 percent of total U.S. GHG emissions 
on a CO2 equivalent basis (using a GWP of 25 for 
methane). With respect to VOC emissions, the transmission and 
storage segment emitted 16,252 tons in 2014, which amounts to just 
0.51 percent of national VOC emissions from that year. With respect 
to SO2 emissions, there were 663 tons emitted from the 
transmission and storage segment in 2014, or just 0.79 percent of 
national SO2 emissions. For HAP emissions, the 
transmission and storage segment emitted 1,143 tons in 2014, or just 
0.01 percent of national HAP emissions for that year.
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D. Rescission of the Applicability to Methane of the NSPS for 
Production and Processing Segments

    As the second of the two steps of its primary proposal, the EPA 
also is proposing to rescind the methane requirements of the NSPS 
applicable to sources in the production and processing segments. The 
EPA is proposing to find that, in the specific circumstances presented 
here, the EPA lacked a rational basis to establish standards of 
performance for methane emissions from the production and processing 
segments because those requirements are entirely redundant with the 
existing NSPS for VOC, establish no additional health protections, and 
are, thus, unnecessary. Rescinding the applicability to methane 
emissions of the 2016 NSPS OOOOa requirements, while leaving the 
applicability to VOC emissions in place, will not affect the amount of 
methane reductions that those requirements will achieve, given the 2016 
NSPS OOOOa compliance monitoring assurances, including technologies and 
frequency of monitoring.
    It is rational for the EPA to determine that requirements that are 
redundant to other requirements are not necessary because they do not 
result in emission reductions beyond what would otherwise occur. For 
example, in its 1977 proposed NSPS for Lime Manufacturing Plants, the 
EPA proposed (and later promulgated) NSPS for particulate matter (PM) 
from lime plants, but not SO2, and explained that the 
particulate controls would have the effect of adequately controlling 
SO2. 42 FR 22506, 22507 (May 3, 1977). See National Lime 
Assoc. v. EPA, 627 F.2d 416, 426 n.27 (D.C. Cir. 1980) (quoting 
statements in the EPA's proposal). In effect, the EPA recognized that 
SO2 requirements would be redundant to PM requirements, and, 
for that reason, declined to impose SO2 requirements.\61\
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    \61\ Similarly, the EPA declined to propose NSPS for (i) 
nitrogen oxides because they are emitted in low concentrations or 
(ii) carbon dioxide because, among other things, regulation would 
produce little environmental benefit, 42 FR 22507. These rationales 
for not proposing controls for air pollutants are similar to the 
redundancy rationale--in all cases, the essential point is that any 
controls would not result in meaningful emission reductions.
---------------------------------------------------------------------------

    The current NSPS requirements as applied to methane are redundant 
with the NSPS requirements as applied to VOC. Indeed, for each emission 
source in the source category subject to the NSPS, the requirements 
overlap completely. To understand this, it is important to recognize 
the emissions profile and control technology for these emission 
sources. Each emission source in the source category emits methane and 
VOC as co-pollutants through the same emission points and processes. 
The requirements of the NSPS, including the emission limits, required 
controls or changes in operations, monitoring, recordkeeping, 
reporting, and all other requirements, apply to each emission source's 
emission points and processes and, therefore, to each emission source's 
methane and VOC emissions, in precisely the same way. The capture and 
control devices that the emission sources use to meet the NSPS 
requirements are the same for these co-pollutants and are not selective 
with respect to either VOC or methane emissions (though the 
concentration of VOC and methane in the gas emitted from any particular 
source will vary across types of affected facilities and geographic 
basins).\62\
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    \62\ Similarly, the capture and control technologies used to 
reduce VOC and methane emissions are also effective in reducing each 
source's emissions of volatile HAP. Please note that while co-
control is a favorable result, 40 CFR part 60, subpart OOOOa does 
not apply to HAP emissions from the source category.
---------------------------------------------------------------------------

    As a result, rescinding the applicability of the NSPS requirements 
to methane emissions will have no impact on the amount of methane 
emissions. Each affected facility in the production and processing 
segments will remain subject to the same NSPS requirements for VOC to 
which it was subject prior to the rescission, and those requirements 
will have the same impact in reducing the emission source's methane 
emissions as before the rescission of the methane requirements.
    For example, the requirements for the collection of fugitive 
emissions components located at a well site include the periodic 
monitoring for fugitive emissions using an optical gas imaging (OGI) 
instrument. This instrument provides real-time visual images of HC gas 
emissions by using spectral wavelength filtering and an array of 
infrared (IR) detectors to visualize the IR absorption of HC and other 
gaseous compounds. As the gas absorbs radiant energy at the same 
waveband that the filter transmits to the detector, the motion of the 
gas is imaged. Since VOC and methane emissions can be imaged within the 
same waveband, the OGI instrument does not allow differentiation or 
speciation of the content of the emissions. Once a fugitive emission is 
identified with OGI, it must be repaired. Therefore, the same 
components are monitored and repaired, regardless of the content of the 
emissions from the affected facility. Thus, the proposed rescission of 
the applicability to methane will not change the applicability of the 
fugitive emissions requirements. The same is true for the other NSPS 
requirements.
    Other examples include the requirements for pneumatic controllers, 
pneumatic pumps, and compressors.

[[Page 50260]]

Pneumatic controllers are automated instruments used for maintaining a 
process condition such as liquid level, pressure, pressure 
differential, and temperature. Pneumatic controllers make use of the 
available high-pressure natural gas to operate or control a valve. 
Natural gas may be released from these ``gas-driven'' pneumatic 
controllers with every valve movement and continuously from the valve 
control pilot. Continuous bleed pneumatic controllers can be classified 
into two types based on their emissions rates: (1) High-bleed 
controllers and (2) low-bleed controllers. Replacing high-bleed 
controllers with low-bleed controllers (or no-bleed and non-gas-driven 
controllers) non-selectively reduces methane and VOC emissions. 
Pneumatic pumps are devices that use gas pressure to drive a fluid by 
raising or reducing the pressure of the fluid by means of a positive 
displacement, a piston or a set of rotating impellers. Gas powered 
pneumatic pumps are generally used at oil and natural gas production 
sites where electricity is not readily available (Gas Research 
Institute/EPA, 1996) and can be a significant source of methane and VOC 
emissions. Routing pneumatic pump emissions to a pre-existing on-site 
control device, which combusts the gas, reduces methane and VOC 
emissions non-selectively. Emissions from compressors occur when 
natural gas leaks around moving parts in the compressor. In a 
reciprocating compressor, emissions occur when natural gas leaks around 
the piston rod when pressurized natural gas is in the cylinder. Over 
time, during operation of the compressor, the rod packing system 
becomes worn and will need to be replaced to prevent excessive leaking 
from the compression cylinder. Replacement of the compressor rod 
packing, replacement of the piston rod, and the refitting or 
realignment of the piston rod reduces methane and VOC emissions non-
selectively. Emissions from centrifugal compressors depend on the type 
of seal used: Either ``wet,'' which uses oil circulated at high 
pressure, or ``dry,'' which uses a thin gap of high-pressure gas. The 
use of dry gas seals substantially reduces emissions. Routing emissions 
to the combustion device is also an option for reducing emissions from 
centrifugal compressors. In either case, the use of dry seals or 
combustion device reduces methane and VOC non-selectively. The proposed 
rescission of applicability to methane will not change the 
applicability of these requirements or that methane will be reduced as 
a co-reduction of VOC.
    Furthermore, any fugitive detection and measurement approach 
currently approved or approved under the Alternative Means of Emissions 
Limitations that speciates emissions, would still identify fugitive 
emissions as defined by any visible emissions observed using OGI and 
require repair. That is, the NSPS requirements as applied to VOC will 
reduce methane in the same amounts as those requirements, as applied to 
methane, would as long as OGI with current levels of sensitivity to 
methane continue to be used. The EPA is aware that several new 
technologies are under development that would detect speciated fugitive 
emissions from oil and natural gas operations. We solicit comment on 
these new technologies and the need to evaluate the current fugitive 
emission detection technology specifications to determine that the 
level of control remains as protective.
    As the EPA noted in the proposal for the 2016 NSPS OOOOa rule, the 
EPA has discretion to determine which pollutants emitted from a listed 
source category warrant regulation. The EPA has historically 
considered, among other things, the amount of the pollutant and ``ha[s] 
`historically declined to propose standards for a pollutant [that] is 
emit[ted] in low amounts. . . .' '' 80 FR 56599 (quoting 75 FR 54970, 
54997 (September 9, 2010).\63\ In the case of the Oil and Natural Gas 
source category, there are no methane emissions from the sources 
subject to the NSPS beyond those emissions already subject to control 
by the provisions to control VOC in the NSPS. Accordingly, there is no 
need to add NSPS requirements applicable to methane.64 65
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    \63\ This discussion assumes that the EPA will retain the 
statutory interpretation set forth in the 2016 NSPS OOOOa rule of 
its authority under CAA section 111 to add new regulations to 
previously-regulated source categories, and that it will not adopt 
the alternative statutory interpretation on which it solicits 
comment in section VI.A below.
    \64\ In the 2016 NSPS OOOOa final rule, the EPA stated: While 
the controls used to meet the VOC standards in the 2012 NSPS also 
reduce methane emissions incidentally, in light of the current and 
projected future GHG emissions from the oil and natural gas 
industry, reducing GHG emissions from this source category should 
not be treated simply as an incidental benefit to VOC reduction; 
rather, it is something that should be directly addressed through 
GHG standards in the form of limits on methane emissions under CAA 
section 111(b) based on direct evaluation of the extent and impact 
of GHG emissions from this source category and the emission 
reductions that can be achieved through the best system for their 
reduction. The standards detailed in this final action will achieve 
meaningful GHG reductions and will be an important step towards 
mitigating the impact of GHG emissions on climate change. 81 FR 
35841.
    After further consideration, the EPA proposes to come to a 
different conclusion about the need for methane requirements, for 
the reasons discussed in this section and below.
    \65\ The EPA notes that removing the applicability of the NSPS 
to methane emissions does not alter the basis for the applicability 
of the NSPS to VOC emissions for affected sources in the source 
category, which for some affected sources have been regulated since 
the 2012 NSPS OOOO rule. To determine BSER, the EPA assesses a set 
of factors, which include the amount of emissions reduction, costs, 
energy requirements, non-air quality impacts, and the advancement of 
particular types of technology or other means of reducing emissions, 
and retains discretion to weight the factors differently in any 
case. In the 2016 NSPS OOOOa, the EPA gave primary weight to the 
amount of emission reductions and cost. The EPA describes this 
analysis in depth in the 2015 NSPS OOOOa proposal at 80 FR 56618-
56620 and 80 FR 56625-56627. For the source types in the production 
and processing segments, the NSPS requirements, considered on a VOC-
only basis, are cost effective (relatively low cost and relatively 
high emissions reductions). See memorandum titled ``Draft Control 
Cost and Emission Changes under the Proposed Amendments to 40 CFR 
part 60, subpart OOOOa Under Executive Order 13783,'' in the public 
docket for this action. The EPA provides this information for the 
benefit of the public and is not reopening the above-described 
determination in the 2016 NSPS OOOOa that the VOC-only requirements 
for sources in the production and processing segments meet the 
requirements of CAA section 111.''
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    The EPA recognizes that in proposing to rescind one set of 
standards in part for its redundancy with another set, the EPA is 
choosing to rescind the applicability of those standards to methane 
emissions and not VOC emissions, rather than vice-versa. Rescinding the 
methane-specific standards is reasonable because the requirements for 
VOC and correspondingly, sources' compliance with those requirements, 
are longer established than those for methane. As described earlier, 
the EPA regulated VOC first, beginning in 1985 and continuing in 2012, 
and then added regulation of methane for some sources in 2016.
    Additionally, redundancy is not uniform across affected facilities 
in the sector. Some sources, such as storage vessels, are subject only 
to VOC requirements and not methane requirements. For those sources, it 
cannot be said that regulation of VOC is redundant to regulation of 
methane because the EPA has not regulated methane from them. For these 
reasons, in choosing between the two requirements, the EPA considers it 
appropriate and less disruptive to rescind the methane standards.

V. Rationale for Alternative Proposal To Rescind the Methane Standards 
for All Sources in the Oil and Gas Source Category Without Revising the 
Source Category

A. Alternative Proposed Action To Rescind the Methane Standards

    In this action, the EPA is proposing in the alternative to rescind 
the methane

[[Page 50261]]

requirements in the 2016 NSPS OOOOa without any action that would 
address the scope of the industry segments covered by these 
requirements or to alter the VOC requirements applicable to those 
industry segments. In contrast to the proposal discussed above in 
section IV, this alternative proposal does not affect the scope of the 
source category, including the types of sources included in the source 
category. Thus, this alternative proposal would not eliminate sources 
in the transmission and storage segment from the source category. This 
alternative proposal is based on the rationale described below.

B. Rationale for Rescinding the Methane Standards

    Under this alternative proposal, the EPA's basis for proposing to 
rescind the applicability to methane of the NSPS for all sources in the 
source category is essentially the same as the EPA's basis for 
proposing the same action for sources in the production and processing 
segments, described in section IV above. Briefly, the EPA is proposing 
to rescind the methane requirements applicable to the source category 
because they are wholly redundant with the existing VOC 
requirements.66 67 Section VI of this preamble takes comment 
on alternative questions of statutory interpretation and associated 
potential record determinations which, if the EPA were to adopt them, 
might provide an additional or alternative basis for both the primary 
and the alternative proposal.
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    \66\ As noted above, in the 2015 proposal for the 2016 NSPS 
OOOOa rule, we justified regulating methane emissions on grounds 
that ``reducing methane emissions from this source category cannot 
be treated simply as an incidental benefit to VOC reduction,'' 80 FR 
56599, but our current view is that what is important is that the 
VOC requirements will assure that the methane emissions reductions 
occur. In addition, as noted above, the cost effectiveness of the 
VOC requirements for sources in the production and processing 
segments supports retaining those requirements for those sources, 
and we are not reopening our determination in the 2016 OOOOa NSPS 
that, on a VOC-only basis, the requirements for sources in the 
production and processing segments meet CAA section 111 
requirements. The same is true for the sources in the transmission 
and storage segment under this alternative proposal. We consider VOC 
emissions regulation alone to qualify as NSPS based on the BSER. As 
we noted with respect to sources in the production and processing 
segments, removing the applicability of the NSPS to methane 
emissions does not alter the basis for the applicability of the NSPS 
to VOC emissions for affected sources in the source category, which 
for some affected sources have been regulated since the 2012 NSPS 
OOOO rule. To determine BSER, the EPA assesses a set of factors, 
which include the amount of emissions reduction, costs, energy 
requirements, non-air quality impacts, and the advancement of 
particular types of technology or other means of reducing emissions; 
this assessment requires the EPA to exercise discretion in weighing 
these factors against each other. In the 2016 NSPS OOOOa, the EPA 
gave primary weight to the amount of emission reductions and cost. 
The EPA describes this analysis in depth in the 2015 proposal at 80 
FR 56616 to 56645. The EPA provides this information for the benefit 
of the public and is not reopening the above-described VOC-only BSER 
determination for the production, processing, transmission, and 
storage segments made in the 2016 NSPS OOOOa.
    \67\ 80 FR 56616 to 56645, 83 FR 52056, and memorandum titled 
``Draft Control Cost and Emission Changes under the Proposed 
Amendments to 40 CFR part 60, subpart OOOOa Under Executive Order 
13783,'' in the public docket for this action.
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VI. Solicitation of Comment on Significant Contribution Finding for 
Methane

    As noted above, the primary and alternative proposals set forth in 
this notice rely on the EPA's previous position, which it took in the 
2016 NSPS OOOOa rule, that (1) CAA section 111 does not require the 
Agency to make a pollutant-specific determination that the Crude Oil 
and Natural Gas Production source category's emissions of methane cause 
or contribute significantly to air pollution that may reasonably be 
anticipated to endanger public health or welfare, as a prerequisite to 
promulgating an NSPS for methane; and (2) in the alternative, if CAA 
section 111 were interpreted to require such a determination for the 
2016 NSPS OOOOa rule, the source category's emissions do cause or 
contribute significantly to air pollution that may reasonably be 
expected to endanger public health or welfare.\68\ Although the 
determination that CAA section 111(b)(1)(A) requires is commonly 
referred to as an ``endangerment finding,'' it entails two separate 
elements: (1) A finding that certain air pollution may reasonably be 
anticipated to endanger public health or welfare, and (2) a finding 
that the source category's emissions of air pollutants cause or 
contribute significantly to that air pollution. This section focuses on 
the latter element, which we refer to as the ``significant contribution 
finding'' (SCF). It should also be noted that in prior contexts in 
which the EPA has made these findings with regard to GHG, including the 
2016 NSPS OOOOa rule, the EPA has considered the ``air pollution'' that 
may reasonably be anticipated to endanger public health or welfare to 
be the elevated concentration in the atmosphere of six well-mixed gases 
(of which, CO2 and methane are emitted in the largest 
quantities); and the EPA has considered the ``air pollutants'' that may 
cause or contribute to that air pollution to be the same six GHG. See 
81 FR 35843. In the 2016 NSPS OOOOa rule, for convenience, the EPA 
sometimes referred to the ``air pollutants'' as methane, in recognition 
of the fact that methane is the largest quantity of GHG emitted by the 
Oil and Natural Gas source category. We take the same approach and use 
the same terminology in this rulemaking.
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    \68\ In the 2016 NSPS OOOOa rule, the EPA stated: Some 
commenters have argued that the EPA is required to make a new 
endangerment finding before it may set limitations for methane from 
the oil and natural gas source category. We disagree. . . . 
Moreover, even if CAA section 111 required the EPA to make an 
endangerment finding as a prerequisite for this rulemaking, then, 
the information and conclusions described above . . . should be 
considered to constitute the requisite finding (which includes a 
finding of endangerment as well as a cause-or-contribute 
significantly finding). More specifically, . . . [t]he facts [that 
the EPA marshaled in support of the 2009 Endangerment Finding] have 
only grown stronger and the potential adverse consequences of GHG to 
public health and the environment more dire [since 2009]. The facts 
also demonstrate that the current methane emissions from oil and 
natural gas production sources and natural gas processing and 
transmission sources contribute substantially to nationwide GHG 
emissions. 81 FR at 35843.
---------------------------------------------------------------------------

    In this proposal, the EPA proposes to retain its current 
interpretation that it is not required to make a pollutant-specific 
SCF, for the same reasons that it noted in the 2016 NSPS OOOOa rule. 81 
FR at 35841-43. However, the EPA solicits comment on whether it should 
revise its positions in the 2016 NSPS OOOOa rule concerning the 
requirement to make a pollutant-specific SCF under CAA section 111(b), 
as well as, in light of the statutory term ``significantly contributes 
to,'' the level of contribution that methane from oil and natural gas 
sources makes to GHG air pollution. In particular, in subsections A, B, 
and C of this section, the EPA solicits comment on (A) whether CAA 
section 111 requires the EPA to make a pollutant-specific SCF for GHG 
emissions (again, primarily methane) from the source category as a 
prerequisite to regulating those emissions; (B) if so, whether the SCF 
for methane emissions from the source category that the EPA made in the 
alternative in the 2016 NSPS OOOOa rule properly satisfied that 
requirement; and (C) what criteria are appropriate for the EPA to 
consider in making a SCF, both as a general matter and with particular 
reference to GHG emissions generally and to methane emissions from this 
source category most particularly. Further, the EPA solicits comment on 
whether, should we determine (1) that it was necessary as a matter of 
law for the EPA to have made a pollutant-specific SCF finding for GHG 
emissions (or, if the statute does not compel that interpretation, 
whether that is a reasonable interpretation); and (2) that the SCF for 
methane emissions

[[Page 50262]]

from the source category that the EPA made in the alternative in the 
2016 NSPS OOOOa rule did not properly satisfy that requirement, those 
determinations, in and of themselves, would either compel us or 
authorize us to repeal the 2016 NSPS OOOOa rule.

A. Requirement for Pollutant-Specific Significant Contribution Finding

    As noted earlier, CAA section 111(b)(1) sets out a multi-step 
process for the EPA to promulgate NSPS. First, the EPA is required to 
list a source category if ``in [the Administrator's] judgment it 
causes, or contributes significantly to, air pollution which may 
reasonably be anticipated to endanger public health or welfare.'' CAA 
section 111(b)(1)(A). Then, the EPA is required to propose and then 
promulgate ``standards of performance for new sources within such 
category.'' CAA section 111(b)(1)(B). A ``standard of performance'' is 
defined as ``a standard for emissions of air pollutants'' that the EPA 
is required to calculate through a particular methodology. CAA section 
111(a)(1). The EPA has interpreted these provisions to require that it 
make a SCF for the combined air pollutant emissions, taken as a whole, 
from the source category in order to list the source category, and then 
to require it to promulgate standards of performance for the emissions 
once it has listed the source category, but not require it to make 
pollutant-specific SCFs as another prerequisite to promulgating those 
standards of performance. 80 FR 64529-31 (Electricity Generating Units 
(EGU) CO2 NSPS rule), 81 FR 35841-42 (2016 NSPS OOOOa rule).
    The EPA articulated this interpretation of CAA section 111(b)(1)(A) 
during the course of two rulemakings to promulgate NSPS for GHG, 
completed in 2015-2016, but commenters called it into question. In 
those rulemakings, the EPA promulgated, for the first time, NSPS for 
GHG, primarily CO2, from fossil-fuel fired EGUs (including 
steam-generating boilers and combustion turbines), ``Standards of 
Performance for Greenhouse Gas Emissions from New, Modified, and 
Reconstructed Stationary Sources: Electric Utility Generating Units--
Final Rule,'' 80 FR 64510, 64530 (October 23, 2015) (EGU CO2 
NSPS rule),\69\ and methane from the Crude Oil and Natural Gas 
Production source category, 81 FR 35843 (the 2016 NSPS OOOOa rule). In 
the proposal for the EGU CO2 NSPS rule, the EPA took the 
position that it was not required to make a pollutant-specific SCF for 
CO2 emissions from EGUs in order to promulgate an NSPS 
regulating those emissions. 79 FR 1430, 1452-55 (January 8, 2014). 
Commenters stated that under the EPA's interpretation, the EPA would 
have the authority to promulgate an NSPS for a air pollutant that a 
source category emits in relatively small amounts (or, with respect to 
the endangerment finding, that is relatively benign in its effect on 
public health or welfare). This is because, under the EPA's 
interpretation, once the Agency lists a source category, it proceeds to 
regulate a particular air pollutant emitted from the category without 
being required to make a SCF for the source category's emissions of 
that air pollutant. See generally 81 FR 35843; 80 FR 64530. These 
concerns about the two GHG NSPS rulemakings are highlighted by the fact 
that when the EPA listed the source categories--EGU Steam-Generating 
Boilers in 1971, Combustion Turbines in 1977, and Crude Oil and Natural 
Gas Production in 1979--and first began to regulate them, the EPA did 
not mention GHG. Rather, the SCFs for the source categories did not 
identify the air pollutants, and the initial regulations--which were 
largely contemporaneous with the listing notices--concerned emissions 
of other air pollutants. See 36 FR 5931 (March 31, 1971), 36 FR 24876 
(December 23, 1971) (EGU Steam-Generating Boilers; (PM, SO2, 
NOX); 42 FR 53657, 42 FR 53782 (October 3, 1977), (EGU 
Combustion Turbines; SO2, NOX); 44 FR 49222 
(August 21, 1979) (Crude Oil and Natural Gas Production; HC and 
SO2). Thus, there is no indication that the EPA considered 
GHG in listing the source categories.
---------------------------------------------------------------------------

    \69\ In the EGU CO2 NSPS rule, the EPA considered the 
``air pollutants'' relevant for the SCF to be GHGs, but because 
CO2 was the GHG emitted in the greatest quantity by EGUs, 
the EPA often described that finding as referring to CO2. 
80 FR 64531 and n.110; 64537.
---------------------------------------------------------------------------

    In both the EGU CO2 NSPS rule and the 2016 NSPS OOOOa 
rule, the EPA asserted that CAA section 111 authorizes it to regulate a 
source category's emissions of an air pollutant without a pollutant-
specific SCF as long as the EPA has a ``rational basis'' for doing so. 
The EPA based this view on previous rulemakings, in which the EPA had 
declined to promulgate NSPS for certain air pollutants from various 
source categories on grounds that the amounts of emissions of those air 
pollutants were so small that regulating them would not be rational, 
and on D.C. Circuit caselaw.\70\ In the EGU CO2 NSPS rule 
and the 2016 NSPS OOOOa rule, the EPA went on to determine that it did 
have a rational basis for regulating CO2 and methane, 
respectively, which consisted of assessing the amount of emissions of 
the GHG from the source category in the light of various metrics, 
coupled with the fact that the EPA had previously determined, in the 
2009 Endangerment Finding, that six well-mixed gases constitute GHG air 
pollution that may reasonably be anticipated to endanger public health 
and welfare under section 202(a) of the CAA. ``Endangerment and Cause 
or Contribute Findings for Greenhouse Gases Under Section 202(a) of the 
Clean Air Act--Final rule,'' 74 FR 66496 (December 15, 2009) (2009 
Endangerment Finding). It should be noted that in both the EGU 
CO2 NSPS rule and the 2016 NSPS OOOOa rule, the EPA also 
stated that, in the alternative, if it were required to make a 
pollutant-specific SCF for GHG (with a focus on CO2 and 
methane, respectively), it was making that finding, citing the same 
information that it relied on for the rational basis determinations. 
See 80 FR 64529-31 (EGU CO2 NSPS rule), 81 FR 35841-43 (2016 
NSPS OOOOa rule) (both citing the 2009 Endangerment Finding).
---------------------------------------------------------------------------

    \70\ Specifically, in the 2016 NSPS OOOOa rule, the EPA stated 
that in National Lime Assoc. v. EPA, 627 F.2d 416 (D.C. Cir. 1980), 
the Court had ``discussed, but did not review, the EPA's reasons for 
not promulgating standards for NOX, SO2, and 
CO from lime plants.'' See 81 FR 35842; see also 80 FR 64530. The 
discussion in National Lime Assoc. consisted of the Court's 
observation, in setting forth the procedural history of the 
rulemaking at issue, that ``[a]lthough lime plants were determined 
to be sources of nitrogen oxides, carbon monoxide and sulfur dioxide 
as well as particulates,'' standards ``were proposed and ultimately 
promulgated only with respect to particulate matter.'' 627 F.2d at 
426. In a footnote, the Court then quoted at length from a portion 
of the preamble to the proposed NSPS in which the EPA had 
``explained its decision not to propose standards'' for those three 
pollutants. Id. at 426 n.27. The only place the phrase ``rational 
basis'' appears in National Lime Assoc. is located in a passage in 
which the Court rejects industry's claim that the EPA had erred in 
its ``determination that lime manufacturing plants `may contribute 
significantly to air pollution which causes or contributes to the 
endangerment of public health or welfare.' '' Id. at 431 n.48. Said 
the Court: ``We think the danger of particulate emissions' effect on 
health has been sufficiently supported in the Agency's . . . 
previous determinations to provide a rational basis for the 
Administrator's finding in this case.'' Id. (emphases added). 
``Moreover,'' the Court continued, ``whatever its impact on public 
health, we cannot say that a dust `nuisance' has no impact on public 
welfare.'' Id. (emphasis added).
---------------------------------------------------------------------------

    In this action, we solicit comment on whether the interpretation of 
CAA section 111(b)(1)(A) that the EPA set forth in the 2016 NSPS OOOOa 
rule is correct, or instead whether that provision should be 
interpreted to require that the EPA make a SCF on a pollutant-specific 
basis for a source category as a prerequisite for regulating emissions 
of that pollutant from the

[[Page 50263]]

source category. The EPA also solicits comment on whether (1) either 
its current interpretation or the alternative interpretation discussed 
in this subsection is the only permissible interpretation of the SCF 
provision, or (2) that provision is ambiguous and leaves room for the 
exercise of policy discretion on the EPA's part as to which 
circumstances call for a pollutant-specific SCF as a predicate for 
regulating an additional pollutant emitted from an already-listed 
source category, and, if the latter, whether GHG emissions in general 
or methane emissions from the oil and natural gas sector in particular 
present specific circumstances making a pollutant-specific SCF 
appropriate or required for this source category. If the provision is 
ambiguous, the benefits of assuring that only pollutants for which the 
EPA makes a SCF become subject to NSPS, as opposed to pollutants that, 
for example, may be emitted in relatively minor amounts, support 
interpreting the provision to require a pollutant-specific SCF.
    The provisions in CAA section 111(b)(1)(A) that require the 
Administrator to ``include a category of sources in such list if in his 
judgment it causes, or contributes significantly to, air pollution 
which may reasonably be anticipated to endanger public health or 
welfare,'' when read in isolation and when compared to analogous text 
in other provisions of similar import elsewhere in the CAA, e.g., 
section 202(a)(1) and other provisions noted below, does appear to 
contemplate that the EPA is required to make a SCF for the source 
category only when it is first added to the list. This was the basis 
for the EPA's position in the EGU CO2 NSPS rule and the 2016 
NSPS OOOOa rule that the Agency is not required to make a pollutant-
specific SCF in order to regulate an additional pollutant from an 
already-listed source category.
    However, even if the wording of the SCF does suggest that the EPA 
is required to make that finding only when listing a source category, 
the EPA is mindful that an Agency ``[may] avoid a literal 
interpretation at Chevron step one . . . [by] show[ing] either that, as 
a matter of historical fact, Congress did not mean what it appears to 
have said, or that, as a matter of logic and statutory structure, it 
almost surely could not have meant it.'' Engine Mfrs. Ass'n v. EPA, 88 
F.3d 1075, 1089 (D.C. Cir. 1996).\71\ We solicit comment on whether the 
discussion below provides either reasons that Congress ``almost surely 
could not have meant'' the SCF provision to mean what the EPA read it 
to mean in the 2016 NSPS OOOOa rule, evidence that ``as a matter of 
historical fact Congress did not mean'' that, or both--and, if so, 
whether the EPA is required to, or whether it would be reasonable for 
the EPA to, adopt an alternative interpretation of CAA section 
111(b)(1)(A) under which the EPA is required to make a pollutant-
specific SCF in order to regulate a particular pollutant emitted by a 
source category.
---------------------------------------------------------------------------

    \71\ See, e.g., Logan v. U.S., 552 U.S. 23, 36-37 (2007) 
(``[s]tatutory terms, we have held, may be interpreted against their 
literal meaning where the words `could not conceivably have been 
intended to apply' to the case at hand [citation omitted]''; U.S. v. 
Ron Pair Enterprises, 489 U.S. 235, 242 (1989) (literal meaning of a 
statutory provision is not conclusive ``in the `rare cases [in 
which] the literal application of a statute will produce a result 
demonstrably at odds with the intentions of the drafters'. . . [in 
which case] the intention of the drafters, rather than the strict 
language, controls'' [citation omitted]); Watt v. Alaska, 451 U.S. 
259, 266 (1981) (``[t]he circumstances of the enactment of 
particular legislation may persuade a court that Congress did not 
intend words of common meaning to have their literal effect'').
---------------------------------------------------------------------------

    There are several reasons why this approach to interpreting CAA 
section 111(b)(1)(A) might be reasonable. The first is the potentially 
anomalous results that could occur under the EPA's current 
interpretation that CAA section 111(b)(1)(A) does not require a 
pollutant-specific SCF. For example, under the EPA's current 
interpretation, the EPA could list a source category on grounds that it 
emits numerous air pollutants that, taken together, significantly 
contribute to air pollution that may reasonably be anticipated to 
endanger public health or welfare, and proceed to regulate each of 
those pollutants, without ever finding that each (or any) of those air 
pollutants by itself causes or contributes significantly to--or, in 
terms of the text of other provisions, causes or contributes to--air 
pollution that may reasonably be anticipated to endanger public health 
or welfare. It is clear that CAA section 111(b) requires the EPA, and 
CAA section 111(d) requires the states, to regulate on a pollutant-by-
pollutant basis--CAA section 111(b)(1)(B) and (d)(1) require the EPA 
and the states, respectively, to promulgate for the affected sources 
``standards of performance,'' which, as noted above, are defined in 
relevant part as ``standard[s] for emissions of air pollutants''--as a 
result, it seems potentially anomalous not to require that the EPA make 
a SCF for those pollutants as a prerequisite for promulgating the 
standards of performance.
    Second, although the EPA's current interpretation that only a 
``rational basis'' is needed to justify regulating emissions of an 
additional pollutant from an already-listed source category offers some 
protection against arbitrary or capricious decisions by the EPA, that 
type of determination appears to be largely undefined. CAA section 
111(b)(1)(A) does not provide or suggest any criteria to define it. In 
the EGU CO2 NSPS and 2016 NSPS OOOOa rules, the EPA did not 
describe any criteria for applying that approach, and in instances 
before then in which the EPA has relied on the ``rational basis'' 
approach, the EPA has done so to justify not setting standards for a 
given pollutant, rather than to justify setting a standard for a 
pollutant. 80 FR 64530. The EPA solicits comment on whether it is 
rational to interpret the SCF provision as setting a specific finding 
that needs to be made only one time (at the stage of source category 
listing), with the standard for the subsequent regulation of some other 
pollutant emitted from that source category defaulting to rational 
basis, a standard which applies to any action the EPA or, in fact, any 
agency, takes, see 5 U.S.C. 706(2)(A) (under the Administrative 
Procedure Act, agency decisions may be set aside if they are 
``arbitrary, capricious, an abuse of discretion, or otherwise not in 
accordance with law''), or whether instead Congress ``almost surely 
could not have meant'' that.
    Third, the other sections of the CAA, cited below, under which the 
EPA makes an endangerment and cause or contribute finding as a 
prerequisite for regulating emissions, do generally contemplate that 
the cause or contribute finding will be made on a pollutant-specific 
basis. The fact that Congress saw fit to frame the cause or contribute 
requirement on a pollutant-specific basis for other CAA provisions 
might reasonably be viewed as heightening the anomaly of interpreting 
CAA section 111(b)(1)(A) not to impose the same requirement. The EPA 
solicits comment on whether its current interpretation of the CAA 
section 111 SCF provision, as set forth in the 2016 NSPS OOOOa rule, 
correctly determined that this apparent anomaly is, in fact, a 
deliberate and significant variation on Congress's part, or whether 
instead Congress ``almost surely could not have meant'' that.
    In addition, the legislative history of CAA section 111(b)(1)(A) 
contains several items that might be read to indicate that Congress did 
``as matter of historical fact'' intend to require that the EPA make a 
pollutant-specific SCF as a prerequisite for regulating any particular 
pollutant emitted by a source category.

[[Page 50264]]

Congress added CAA section 111 when it amended the CAA in 1970. At that 
time, Congress drafted CAA section 111(b)(1) in much the same form as 
it appears today, explicitly requiring the endangerment finding, 
including the SCF, on the basis of the source category, although it 
phrased the finding somewhat differently: ``[The Administrator] shall 
include a category of sources in such list if he determines it may 
contribute significantly to air pollution which causes or contributes 
to the endangerment of public health or welfare.'' 42 U.S.C. 1857c-
6(b)(1)(A) (1970). At the same time, Congress added several other 
provisions that contemplated that the EPA would make endangerment or 
cause or contribute findings, and although Congress used somewhat 
different phrasing in some of those provisions, in each one, Congress 
framed the relevant finding on a pollutant-specific basis. See CAA 
section 108(a)(1)(A)-(B), 42 U.S.C. 1857c-3(a)(1)(A)-(B) (1970) 
(Administrator is required to publish a list ``which includes each air 
pollutant which in his judgment has an adverse effect on public health 
or welfare'' and ``the presence of which in the ambient air results 
from numerous or diverse mobile or stationary sources''); \72\ CAA 
section 115(a), 42 U.S.C. 1857d(a) (1970) (Administrator is authorized 
to take action to address ``pollution of the air in any State or States 
which endangers the health or welfare of any persons''); CAA section 
202(a)(1), 42 U.S.C. 1857f-1(a)(1) (1970) (Administrator is required to 
regulate ``the emission of any air pollutant from any class or classes 
of new motor vehicles or new motor vehicle engines, which in his 
judgment causes or contributes to, or is likely to cause or to 
contribute to, air pollution which endangers the public health or 
welfare''); \73\ CAA section 211(c)(1), 42 U.S.C. 1857f-6(c)(1) (1970) 
(Administrator is authorized to regulate ``any fuel or fuel additive 
for use in a motor vehicle or motor vehicle engine if any emission 
products of such fuel or fuel additive will endanger the public health 
or welfare''); CAA section 231(a)(2), 42 U.S.C. 1857f-9(a)(2) (1970) 
(Administrator is required to regulate ``emissions of any air pollutant 
from any class or classes of aircraft or aircraft engines which in his 
judgment cause or contribute to or are likely to cause or contribute to 
air pollution which endangers the public health or welfare'').
---------------------------------------------------------------------------

    \72\ This provision is similar to section 3(c)(2) of the CAA of 
1963, Public Law 88-206 (December 17, 1963): Whenever [the Secretary 
of the Department of Health, Education, and Welfare] determines that 
there is a particular air pollution agent (or combination of 
agents), present in the air in certain quantities, producing effects 
harmful to the health or welfare of persons, the Secretary shall 
compile and publish criteria reflecting accurately the latest 
scientific knowledge useful in indicating the kind and extent of 
such effects which may be expected from the presence of such air 
pollution agent (or combination of agents) in the air in varying 
quantities.
    \73\ This provision is similar to section 202(a) of the CAA, as 
adopted in the Motor Vehicle Air Pollution Control Act of 1965, 
Pubic Law 89-271 (October 19, 1965): The Secretary shall by 
regulation, giving appropriate consideration to technological 
feasibility and economic costs, prescribe as soon as practicable 
standards, applicable to the emission of any kind of substance, from 
any class or classes of new motor vehicles or new motor vehicle 
engines, which in his judgment cause or contribute to, or are likely 
to cause or to contribute to, air pollution which endangers the 
health or welfare of any persons. . . .
---------------------------------------------------------------------------

    In the 1970 CAA Amendments, Congress did not explain why it used 
language in CAA section 111 that suggested a SCF for the source 
category under CAA section 111 while using pollutant-specific language 
in the other provisions, but the reason appears to be that under CAA 
section 111, Congress tasked the EPA with determining, among the large 
numbers of highly diverse stationary sources in the U.S., which ones, 
grouped into which source categories, should be listed and subject to 
regulation. It was logical for Congress to constrain the EPA's 
discretion by requiring that the EPA make a SCF for each source 
category that it sought to list. While it is true that in drafting CAA 
section 111(b)(1)(A), Congress did not explicitly require the EPA to 
make an additional, pollutant-specific SCF, it seems reasonable to 
think that Congress may have intended pollutant-specific SCF findings 
but conflated them with the required source-category SCF finding. 
Support for this interpretation may be found in the fact that under CAA 
section 111, a source category can cause or significantly contribute to 
air pollution only through emissions of its air pollutants, CAA section 
111(b)(1)(B) requires the EPA to promulgate ``standards of 
performance'' for air pollutants, and CAA section 111(a)(1) defines a 
``standard of performance'' as a ``standard of emissions for air 
pollutants'' (emphasis added). The EPA solicits comment on whether 
these provisions, read together with CAA section 111(b)(1)(A), are 
evidence that Congress intended the latter to require what is required 
in the other CAA provisions discussed here: A pollutant-specific 
finding. Certainly, interpreting CAA section 111(b)(1)(A) to require 
such a pollutant-specific finding would make it consistent with those 
other CAA provisions.
    In the 1977 CAA Amendments, Congress rephrased the text in each of 
the above-noted provisions to read as they do at present, which is 
generally the same phrasing as in CAA section 111(b)(1)(A) in relevant 
part, except that for the other provisions, Congress did not require 
the contribution component of the findings to be based on a 
``significant'' contribution and, with the possible exception of CAA 
section 202(a), discussed below, Congress continued to focus the cause 
or contribute findings on air pollutants. The legislative history 
generally describes Congress's purpose as providing, across all the 
relevant provisions, and consistent with the D.C. Circuit's decision in 
Ethyl Corp. v. EPA, 541 F.2d 1 (D.C. Cir.) (en banc), cert. den. 426 
U.S. 941 (1976), a uniform standard of proof that allows the 
Administrator to regulate pollutants based on the need to prevent harm 
before it occurs, rather than require the Administrator to delay 
regulating until after actual harm has been proven to have occurred. 
H.R. Rep. No. 94-1175 at 32-33 (1976).
    Importantly, the legislative history of the 1977 SCF provisions can 
also be read as evidence that Congress understood at that time that the 
EPA was to make a pollutant-specific SCF under CAA section 111. The SCF 
provisions originated in the House bill, did not have a counterpart in 
the Senate bill, and were adopted by the Conference Committee as they 
appeared in the House bill. The Conference Report summarized the House 
bill as follows, in relevant part:

House bill

    Provides a uniform standard of proof for EPA regulation of air 
pollutants which applies to the setting of . . . criteria for 
national ambient air quality standards under Section 108; . . . new 
stationary source performance standards under Section 111; . . . new 
auto emission standards under Section 202; . . . regulations of 
fuels and fuel additives under Section 211; aircraft emission 
standards under Section 231.
    In all future rulemaking in these areas, the Administrator could 
regulate any air pollutant from those sources, the emissions of 
which ``in his judgment cause or contribute to air pollution which 
may reasonably be anticipated to endanger public health or 
welfare.''

H.R. Rep. No. 95-564, at 183-84 (1977) (emphasis added). The emphasized 
language may be evidence that Congress, in fact, intended to require 
the EPA (or, indeed, understood that the EPA had always been required), 
in promulgating a pollutant-specific NSPS under CAA section 111, to 
make a pollutant-specific finding, as it does

[[Page 50265]]

under the other provisions mentioned in the Conference Report.
    The House Committee Report included a similar statement in 
describing one of its purposes for rephrasing the various endangerment 
finding provisions: ``To provide the same standard of proof for 
regulation of any air pollutant, whether that pollutant comes from 
stationary or mobile sources, or both, and to make the vehicle and fuel 
industries equally responsible for cleaning up vehicle exhaust 
emissions.'' H.R. Rep. No. 94-1175, at 33 (1976) (emphasis added). The 
emphasized phrase could suggest that the House Committee drafters 
understood the SCF provision in CAA section 111(b)(1)(A) to concern the 
particular air pollutant subject to regulation (i.e., the NSPS), like, 
at least for the most part, the other analogous provisions.\74\
---------------------------------------------------------------------------

    \74\ It should be noted that in the 1970 and 1977 CAA 
Amendments, Congress added or amended several other provisions that 
included findings similar to the findings in CAA sections 
108(a)(1)(A), 111(b)(1)(A), 115, 202(a), 211(c)(1), and 
231(a)(2)(A). These provisions include the following, (as they read 
after the 1977 CAA Amendments and before any changes in the 1990 CAA 
Amendments): (1) CAA section 112 (added in 1970 CAA Amendments and 
revised in 1977 CAA Amendments; ``hazardous air pollutant'' is 
defined as, in relevant part, ``an air pollutant . . . which in the 
judgment of the Administrator causes, or contributes to, air 
pollution which may reasonably be anticipated to result in an 
increase in mortality or an increase in serious irreversible, or 
incapacitating reversible, illness;'' this definition was 
substantially revised in 1990 CAA Amendments); and (2) CAA section 
211(c)(1)(A) (added in 1970 CAA Amendments and revised in 1977 CAA 
Amendments; the Administrator is authorized to regulate any fuel or 
fuel additive ``if in the judgment of the Administrator any emission 
product of such fuel or fuel additive causes, or contributes, to air 
pollution which may reasonably be anticipated to endanger the public 
health or welfare''). In addition, in the 1990 CAA Amendments, 
Congress added several additional provisions that require findings 
that bear some similarity to the findings discussed above. See (1) 
CAA section 129(e) (Administrator or state is required to ``require 
the owner or operator of any unit to comply with emission 
limitations or implement any other measures, if the Administrator or 
the state determines that emissions in the absence of such 
limitations or measures may reasonably be anticipated to endanger 
public health or the environment''); (2) CAA section 183(f)(1)(A) 
(Administrator is required to promulgate standards for VOC and any 
other air pollutant from loading and unloading of tank vessels 
``which the Administrator finds causes, or contributes to, air 
pollution that may be reasonably anticipated to endanger public 
health or welfare''); (3) CAA section 213(a)(1)-(3) (Administrator 
is required to (i) conduct a study to determine if emissions from 
nonroad engines and nonroad vehicles ``cause, or significantly 
contribute to, air pollution which may reasonably be anticipated to 
endanger public health or welfare;'' (ii) determine whether 
emissions of certain pollutants from new and existing nonroad 
engines and vehicles ``are significant contributors to ozone or 
carbon monoxide concentrations in more than 1 area which has failed 
to attain the national ambient air quality standards (NAAQS) for 
ozone or carbon monoxide;'' and if so, (iii) promulgate regulations 
containing standards applicable to such emissions from those classes 
or categories of new nonroad engines and new nonroad vehicles 
``which in the Administrator's judgment cause, or contribute to, 
such air pollution'') (CAA section 213(a)(4), which concerns 
different pollutants than under CAA section 213(a)(2)-(3), has 
requirements similar to the requirements of those provisions); (4) 
CAA section 615 (Administrator is required to regulate ``[i]f, in 
the Administrator's judgment, any substance, practice, process, or 
activity may reasonably be anticipated to affect the stratosphere, 
especially ozone in the stratosphere, and such effect may reasonably 
be anticipated to endanger public health or welfare''). For the most 
part, these provisions contemplate endangerment or cause or 
contribute findings, or similar determinations, for a pollutant, 
emissions, or substance, and for that reason, could support 
interpreting CAA section 111(b)(1)(A) to require a pollutant-
specific SCF.
---------------------------------------------------------------------------

    Other provisions Congress added into CAA section 111 during the 
1977 CAA Amendments might also shed light on the meaning of the SCF 
provision. Congress was dissatisfied at what it perceived to be the 
slow pace of the EPA's regulation under CAA section 111, and as a 
result, added provisions (which have continued in effect) that required 
the EPA to include on the list required under CAA section 111(b)(1)(A) 
the categories of major stationary sources not already on the list, and 
promulgate standards of performance for those categories on a specified 
schedule. CAA section 111(f)(1). Congress further directed the EPA to 
determine priorities for promulgating standards for the listed 
categories by considering, among other things, ``the quantity of air 
pollutant emissions which each such category will emit, or will be 
designed to emit,'' and ``the extent to which each such pollutant may 
reasonably be anticipated to endanger public health or welfare.'' CAA 
section 111(f)(2)(A)-(B) (emphasis added).\75\ The emphasized text 
could be interpreted to indicate that Congress recognized the EPA's 
ability to consider, under CAA section 111, the impacts of specific 
pollutants on public health or welfare. Further, the fact that the 
emphasized text is phrased in terms of ``the extent to which each such 
pollutant'' is determined by the EPA to ``endanger public health or 
welfare,'' rather than simply ``whether each such pollutant may 
reasonably be anticipated to endanger public health or welfare,'' might 
be reasonably construed as indicating that Congress presupposed that, 
in taking account of the ``air pollutant emissions which each such 
category will emit, or will be designed to emit'' for the purpose of 
prioritizing the establishment of standards of performance for sources 
within each category, the EPA would only be establishing standards of 
``air pollutant emissions'' that ``may reasonably be anticipated to 
endanger.'' \76\
---------------------------------------------------------------------------

    \75\ In the 1990 CAA Amendments, Congress revised the provisions 
of CAA section 111(f)(1) directing the EPA to promulgate standards 
for listed categories and retained the provisions of CAA section 
111(f)(2) for prioritizing.
    \76\ It is perhaps significant, too, that Congress in CAA 
section 111(f)(2) tied the finding of ``endangerment'' not to ``air 
pollution'' that endangers, as is the case with respect to every 
section of the CAA where the concept of ``cause or contribute to'' 
is employed but, rather, to ``each such pollutant.'' This particular 
formulation is used nowhere else in the CAA and arguably suggests 
that Congress had a pollutant-specific SCF in mind.
---------------------------------------------------------------------------

    CAA section 122(a), also added in the 1977 CAA Amendments (and 
still in effect), could also shed light on the meaning of the SCF 
provision of CAA section 111(b)(1)(A). Section 122(a) of the CAA 
requires the Administrator ``to determine whether or not emissions of 
radioactive pollutants . . ., cadmium, arsenic and polycyclic organic 
matter into the ambient air will cause, or contribute to, air pollution 
which may reasonably be anticipated to endanger public health.'' 
Further, ``[i]f the Administrator makes an affirmative determination 
with respect to any such substance,'' the Administrator is required, 
depending on the substance, to include it on the list published under 
CAA section 108 or 112, ``or shall include each category of stationary 
sources emitting such substance in significant amounts in the list 
published under section 111(b)(1)(A). . . .'' CAA section 122(a) 
(emphasis added). Here, too, the emphasized provisions could be 
interpreted to indicate that Congress expected the EPA to make 
pollutant-specific determinations under CAA section 111(b).
    In addition, the EPA's interpretation of the cause or contribute 
finding required under CAA section 202(a) could serve as a precedent 
for interpreting CAA section 111(b)(1)(A) as requiring a pollutant-
specific SCF. CAA section 202(a)(1), as revised by the 1977 CAA 
Amendments, provides, in relevant part: ``The Administrator shall by 
regulation prescribe . . . standards applicable to the emission of any 
air pollutant from any class or classes of new motor vehicles or new 
motor vehicle engines, which in his judgment cause, or contribute to, 
air pollution which may reasonably be anticipated to endanger public 
health or welfare'') (emphasis added). 42 U.S.C. 7521(a)(1) (1977). The 
emphasized term, ``cause, or contribute,'' is plural, which could 
suggest that it refers to ``any class or classes of new motor vehicles 
or new motor vehicle engines,'' and thereby contemplates that the cause 
or contribute finding would be made based on the emissions, considered 
all

[[Page 50266]]

together, from the source category, not on the basis of individual 
pollutants. However, the EPA has interpreted this provision to instruct 
the Administrator to make the cause or contribute finding on a 
pollutant-specific basis. See 74 FR 66496, 66506 (2009 Endangerment 
Finding). The EPA's interpretation of CAA section 202(a) to contemplate 
a pollutant-specific finding could support the reasonableness of 
interpreting CAA section 111(b)(1)(A) to contemplate the same thing.
    In fact, it appears to be the case that the EPA in the past did so 
interpret CAA section 111(b)(1)(A) to require a pollutant-specific SCF 
as a prerequisite for regulating that pollutant. In the first guideline 
document the EPA issued under CAA section 111(d) (i.e., for emissions 
from existing phosphate fertilizer plants), the EPA summarized CAA 
section 111(b)(1)(A) (as it read prior to revision in the 1977 CAA 
Amendments) as follows:

    The Administrator first considers potential health and welfare 
effects of a designated pollutant in connection with the 
establishment of standards of performance for new sources of that 
pollutant under section 111(b) of the Act. Before such standards may 
be established, the Administrator must find that the pollutant in 
question ``may contribute significantly to air pollution which 
causes or contributes to the endangerment of public health or 
welfare'' [see section 111(b)(1)(A)]. Because this finding is, in 
effect, a prerequisite to the same pollutant being identified as a 
designated pollutant under section 111(d), all designated pollutants 
will have been found to have potential adverse effects on public 
health, public welfare, or both.

``Final Guideline Document: Control of Fluoride Emissions from Existing 
Phosphate Fertilizer Plants,'' U.S. Environmental Protection Agency, 
EPA-450/2-77-005 (March 1977) at 2-1 (emphasis added). The emphasized 
statements reflect a straight-forward interpretation of CAA section 
111(b) as requiring a pollutant-specific SCF as a pre-requisite to 
promulgating an NSPS for that pollutant. This very same language 
appears in each of the three guideline documents that the EPA 
subsequently issued pursuant to CAA section 111(d).\77\ Although these 
statements from the EPA stand in contrast to later EPA statements that 
characterize CAA section 111(b) as requiring that the SCF be made on 
the basis of the source category, they suggest uncertainty as to 
whether CAA section 111(b)(1)(A) should not be read to require a SCF 
for specific pollutants.\78\
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    \77\ See ``Final Guideline Document: Control of Sulfuric Acid 
Mist from Existing Sulfuric Acid Production Units,'' U.S. 
Environmental Protection Agency, EPA-450/2-77-0019 (September 1977) 
at 5-1; ``Control of TRS Emissions from Existing Mills,'' U.S. EPA, 
EPA-450/2-78-003b (March 1979) at 2-1; ``Primary Aluminum: 
Guidelines for Control of Flouride Emissions from Existing Primary 
Aluminum Plants,'' U.S. EPA, EPA-450/2-78-049b (December 1979) at 2-
1. Similarly, in its rulemaking establishing the regulatory process 
for emissions from existing sources under CAA section 111(d), which 
preceded the development of these guideline documents, the EPA had 
stated: [S]ection 111(d) requires control of existing sources of a 
pollutant if a standard of performance is established for new 
sources under section 111(b) and the pollutant is not controlled 
under sections 108-110 or 112. In general, this means that control 
under section 111(d) is appropriate when the pollutant may cause or 
contribute to endangerment of public health or welfare but is not 
known to be ``hazardous'' within the meaning of section 112 and is 
not controlled under sections 108-110. . . .
    ``State Plans for the Control of Certain Pollutants from 
Existing Facilities,'' 40 FR 53340 (November 17, 1975) (emphasis 
added).
    \78\ In another EPA document issued some 18 months after 
promulgation of the first set of standards of performance (for five 
source categories) in December 1971, the EPA provided a summary of 
the second group of standards (for a further seven source 
categories) for which rulemaking had then been initiated. In 
providing at the outset of that document what it called a 
``synopsis'' of CAA section 111, the EPA stated that the ``Section 
provides that, for purposes of establishing such standards, the 
Administrator may distinguish between types, sizes, and classes of 
sources; and that standards can be established for any pollutant 
that contributes to the endangerment of health and welfare.'' See 
Group II New Source Performance Standards, EPA Doc. 450S7001 
(January 1973) (emphasis added).
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    In light of the considerations described above, the EPA solicits 
comment on whether CAA section 111(b)(1)(A) should be interpreted to 
require it to make a pollutant-specific SCF as a prerequisite for 
promulgating an NSPS for that pollutant. CAA section 111(b)(1)(A)'s SCF 
provision, when read in isolation, may appear to require a SCF for the 
source category as a prerequisite for listing the source category. 
However, should the EPA instead conclude that Congress could not have 
intended that the EPA promulgate NSPS without a pollutant-specific SCF 
in light of, among other considerations, (1) the fact that Congress 
adopted at the same time and subsequently amended at the same time 
similarly phrased CAA provisions that do contemplate a pollutant-
specific finding prior to regulation, (2) the inherent vagueness of the 
rational basis approach, and (3) the indications in the legislative 
history that Congress did intend that the EPA make a pollutant-specific 
SCF under CAA section 111?
    It should be noted that requiring a pollutant-specific SCF need not 
result in duplicative SCFs (or duplicative associated endangerment 
findings), that is, the EPA would not need to make separate SCFs (and 
associated endangerment findings) for both the source category and each 
pollutant emitted by the source category that the EPA seeks to 
regulate. Rather, in beginning to regulate pollutants from a previously 
unlisted source category, the EPA could identify any pollutant it seeks 
to regulate and, if appropriate, make a SCF (and associated 
endangerment finding) for that pollutant as emitted by that source 
category. Such a SCF would serve as the ``cause[ ], or contribute[ ] 
significantly to'' finding both for listing the source category and for 
promulgating an NSPS for the pollutant.
    The EPA recognizes it has proceeded under the implicit assumption 
that CAA section 111(b)(1)(A) does not require a pollutant-specific SCF 
through many NSPS rulemakings over a lengthy period. The EPA solicits 
comment on what the implications would be to the CAA section 111 
program, including the current NSPS and CAA section 111(d) guideline 
documents and state plans, of interpreting CAA section 111(b)(1)(A) to 
require a pollutant-specific SCF. In this regard, the EPA notes that, 
for the most part, its past practice has been to list a source category 
and to propose NSPS for pollutants from the source category at the same 
time as, or shortly after the listing, and to finalize the NSPS shortly 
after that. It seems evident that those NSPS concerned pollutants that 
the EPA considered in listing the source category. The EPA solicits 
comment on whether, under those circumstances, the EPA could be 
considered to have made SCFs and endangerment findings for those 
pollutants, so that it would not be necessary to make those findings 
now. However, in some cases, the EPA promulgated NSPS for air 
pollutants that the EPA did not address in listing the source category 
or in the initial set of regulations promulgated at the same time, or 
shortly after, the EPA listed the source category. For example, the EGU 
CO2 NSPS and the 2016 NSPS OOOOa rules addressed GHG 
pollutants that the EPA had not identified in the initial SCF it made 
for those source categories or in the rulemakings promulgating the 
initial NSPS for those source categories. The EPA solicits comment 
specifically on whether the considerations noted above indicate that 
CAA section 111(b)(1)(A) should be interpreted to require a pollutant-
specific SCF as a prerequisite for promulgating an NSPS for a pollutant 
that the EPA did not identify when it made the initial source-category 
SCF or promulgated the initial regulations for the source category. In 
addition, the EPA solicits comment on whether, if CAA section 
111(b)(1)(A) is interpreted to be ambiguous as to

[[Page 50267]]

whether it requires a pollutant-specific SCF, the EPA could decide that 
it needs to make the SCF and associated endangerment findings for 
pollutants that, like GHG, it did not address when it listed the source 
category or shortly thereafter, but that it does not need to make those 
findings for pollutants that it did address at that time. Furthermore, 
the EPA solicits comment on whether, in light of the fact that CAA 
section 111(b)(1)(A) explicitly phrases the requisite finding in terms 
of ``causes, or contributes significantly to, air pollution [that meets 
the endangerment criteria]'' (emphasis added), there is any basis for 
interpreting the provision to require the EPA to make only a ``cause or 
contribute'' finding, of the type required under, for example, CAA 
section 202(a).

B. Significant Contribution Finding in 2016 NSPS OOOOa Rule

    The EPA also solicits comment on whether, assuming it is required 
to make a SCF for methane emissions from the Oil and Natural Gas source 
category as a prerequisite to promulgating an NSPS for methane, the SCF 
it made in the 2016 NSPS OOOOa rule was an appropriate methane-specific 
finding.\79\ At the outset, it should be noted that that SCF concerned 
emissions from the production, processing, transmission, and storage 
segments of the oil and natural gas industry. 81 FR 35841-43. In this 
proposed rulemaking, the EPA proposes to eliminate the transmission and 
storage segment from the source category. Accordingly, the appropriate 
SCF for methane from this source category would be limited to methane 
emissions from production and processing sources. The EPA solicits 
comment on whether the SCF in the 2016 NSPS OOOOa rule can be 
considered appropriate in light of the fact that it was based on a 
greater amount of emissions than are in the source category as proposed 
in this rulemaking.
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    \79\ As noted in section VI.A. above, in the 2016 NSPS OOOOa 
rule, the air pollutant for which the EPA made the SCF was GHG, but 
because methane constitutes most of the GHG emitted from the Oil and 
Natural Gas source category, the EPA generally refers to methane as 
the subject of the SCF.
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    In addition, we solicit comment on the question whether the SCF in 
the 2016 NSPS OOOOa rule can be considered appropriate given that 
nowhere in the course of developing and promulgating that rule did the 
EPA set forth the standard by which the ``significance'' of the 
contribution of the methane emissions from the source category (as 
revised) was to be assessed.\80\ Specifically, we ask for comment on 
whether, as a matter of law, under CAA section 111, the EPA is 
obligated to identify the standard by which it determines whether a 
source category's emissions ``contribute significantly,'' and whether, 
if not so obligated, the EPA nevertheless fails to engaged in reasoned 
decision-making by not identifying that standard. Cf. Motor Vehicle 
Mfrs. Assn. of United States, Inc. v. State Farm Mut. Automobile Ins. 
Co., 463 U. S. 29, 43 (1983) (``Normally, an agency rule would be 
arbitrary and capricious if the agency has . . . entirely failed to 
consider an important aspect of the problem.'').
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    \80\ In the 2016 NSPS OOOOa rule, the EPA averred that the 
``collective GHG emissions from the oil and natural gas source 
category are significant, whether the comparison is domestic . . . 
global . . . , or when both the domestic and global GHG emissions 
comparisons are viewed in combination,'' basing its position on data 
showing that the source category accounts for 32 percent of United 
States methane emissions, 3.4 percent of total United States GHG 
emissions, and 0.5 percent of all global GHG emissions.'' See 81 FR 
35840.
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C. Criteria for Making a Significant Contribution Finding Under CAA 
Section 111

    The EPA also solicits comments on the appropriate criteria for it 
to use when determining whether a pollutant emitted from a source 
category significantly contributes to air pollution which may 
reasonably be anticipated to endanger in the context of CAA section 
111. The EPA does not intend for these comments to inform the 
finalization of this rule, but rather to inform the EPA's actions in 
future rules. Furthermore, the EPA is not asking for comment on the 
factors the Agency should consider in determining whether air pollution 
may reasonably be anticipated to endanger public health or welfare, but 
rather the factors that should be considered when determining under CAA 
section 111 whether a pollutant from a source category significantly 
contributes to that air pollution.
    In subsection 1 of this section, the EPA discusses other contexts 
under the CAA in which it has interpreted and applied similar language 
to that governing the SCF determinations under CAA section 
111(b)(1)(A). In subsection 2, the EPA identifies and solicits comment 
on specific elements of criteria that might govern SCF determinations. 
In subsection 3 of this section, the EPA provides background 
information concerning methane and GHG emissions that may be relevant 
for application of those criteria to those particular pollutants.
1. Legal Background for Selection of Criteria for Significant 
Contribution Finding
    The phrase ``contributes significantly'' and the included terms 
``contributes'' and ``significantly'' are not defined in any provision 
of the CAA or in EPA regulations. Accordingly, the EPA has substantial 
discretion in interpreting these terms and should receive deference for 
a reasonable interpretation of the provision. The U.S. Supreme Court, 
in EPA v. EME Homer City Generation, L.P., 572 U.S. 489 (2014), 
recognized that a similar provision in CAA section 110(a)(2)(D)(i), 
often termed the ``good neighbor'' provision, is ambiguous and approved 
the EPA's interpretation.\81\
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    \81\ In an earlier case concerning the good neighbor provision, 
the D.C. Circuit noted that the term ``significant'' is ambiguous 
and may be subject to different meanings in different contexts. 
Michigan v. EPA, 213 F.3d 663, 677 (D.C. Cir. 2000). The D.C. 
Circuit has also observed that the term ``contribute'' is ambiguous. 
Catawba County, N.C. v. EPA, 571 F3d 20, 38-39 (D.C. Cir. 2009). 
There, the Court interpreted the requirement under CAA section 
107(d) that the EPA designate an area nonattainment if it does not 
meet the NAAQS or ``contributes to ambient air quality in a nearby 
area that does not meet'' the NAAQS. The Court concluded that the 
EPA has discretion in devising criteria or factors in determining 
the amount of emissions that it considers ``contribute.''
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    The good neighbor provision requires states to prohibit emissions 
``in amounts which will contribute significantly to nonattainment'' of 
the NAAQS in any other state. For regional pollutants like ozone and 
fine PM, where downwind air quality problems are caused by the 
collective contribution of numerous upwind sources across multiple 
states, the EPA has considered a variety of factors when determining 
whether sources in a particular state will ``contribute significantly'' 
under this statutory provision. The EPA has typically first used an air 
quality threshold to identify upwind states that contribute to and are, 
therefore, ``linked'' to a downwind air quality problem. See, e.g., 
Cross-State Air Pollution Rule (CSAPR), 76 FR 48208, 48236 (August 8, 
2011) (upwind states with impacts in a downwind area that meet or 
exceed 1 percent of the 1997 ozone, 1997 p.m. with a diameter of 2.5 
micrometers or less (PM2.5), and 2006 PM2.5 NAAQS 
are considered linked to downwind air quality problems); CSAPR Update, 
81 FR 74504, 74518 (October 26, 2016) (applying threshold equivalent to 
1 percent of the 2008 ozone NAAQS). The EPA has then used a multi-
factor test considering both cost and air-quality factors to determine 
what portion of a linked state's contribution to an air quality 
problem,

[[Page 50268]]

if any, is considered ``significant'' and, thus should be prohibited 
under the good neighbor provision. See CSAPR, 76 FR 48248-249; CSAPR 
Update, 81 FR 74519. In EME Homer City Generation, the Supreme Court 
affirmed the EPA's approach of apportioning emission reduction 
responsibility based on which states can eliminate emissions most cost-
effectively. 572 U.S. at 519 (explaining that ``[e]liminating those 
amounts that can cost-effectively be reduced is an efficient and 
equitable solution to the allocation problem the Good Neighbor 
Provision compels the Agency to address.'').\82\
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    \82\ The good neighbor provision also instructs states to 
prohibit emissions which will ``interfere with maintenance'' of the 
NAAQS in downwind states, and the Supreme Court affirmed that this 
provision ``entails a delegation of administrative authority of the 
same character as'' the ``contribute significantly'' clause. EME 
Homer City Generation, 572 U.S. at 515 n.18. The EPA has, therefore, 
used the same two-step approach to identifying and apportioning 
emission reduction responsibility among upwind states linked to 
downwind areas that struggle to maintain the NAAQS.
---------------------------------------------------------------------------

    The EPA has also considered the meaning of ``contributes 
significantly'' as it appears in CAA section 189(e). This provision 
requires that the control requirements applicable to major stationary 
sources of PM with a diameter of 10 micrometers or less 
(PM10) also apply to major stationary sources of 
PM10 precursors, ``except where the Administrator determines 
that such sources [of precursors] do not contribute significantly to 
PM10 levels which exceed the standard in the area.'' 
Consistent with the D.C. Circuit's decision in NRDC v. EPA, 706 F.3d 
428 (D.C. Cir. 2013), this provision also applies to the regulation of 
sources of PM2.5 precursors in designated PM2.5 
nonattainment areas.
    The EPA has interpreted and applied CAA section 189(e) in its 
recent PM2.5-state implementation plan (SIP) regulations, 
``Fine Particulate Matter National Ambient Air Quality Standards: State 
Implementation Plan Requirements; Final Rule,'' 81 FR 58010 (August 24, 
2016) (PM2.5 SIP Requirements Rule); and provided additional 
information in a recent draft guidance document. U.S. EPA, Office of 
Air Quality Planning and Standards, ``PM2.5 Precursor 
Demonstration Guidance,'' EPA-454/R-19-004 (May 2019) (PM2.5 
Precursor Guidance). The EPA noted that, although the phrase 
``contribute significantly'' and its included terms, ``contribute'' and 
``significantly,'' are ambiguous, Congress has provided some direction 
regarding the degree of contribution required by modifying the term 
``contribute'' with the term ``significantly.'' This indicates that 
Congress intended that, in order to be subject to regulation, the 
emissions must have a greater impact than a simple contribution not 
characterized as ``significant[ ].'' However, Congress did not quantify 
how much greater. Therefore, the EPA developed criteria for identifying 
whether the impact of a particular precursor would ``contribute 
significantly'' to a NAAQS exceedance. Id. at 10-13. First, the EPA 
identified concentration values, based on the amount of observed 
variability of ambient air quality levels, which would be used to 
determine whether a precursor ``contributes'' in a state's analysis. 
The EPA specified numerical thresholds for the annual PM2.5 
NAAQS (0.2 microgram per cubic meter ([micro]g/m\3\)) and 24-hour 
PM2.5 NAAQS (1.5 [micro]g/m\3\), so that any impact less 
than those amounts is considered insignificant. Id. at 17.
    However, the EPA added that if the estimated air quality impact of 
precursor emissions exceeds the applicable threshold, that does not 
necessarily mean that the precursors' contribution to those levels is 
``significant[ ].'' Rather, ``the significance of a precursor's 
contribution is to be determined `based on the facts and circumstances 
of the area.''' Id. at 18, (quotation is found in 40 CFR 51.1006(a) 
(various provisions) (the PM2.5 SIP Requirements Rule). The 
guidance goes on to list factors that may be relevant, including among 
others, the amount by which a precursor's impact exceeds the 
recommended contribution threshold, the sources of PM2.5, 
trends in precursor emissions, and the extent of the PM2.5 
air pollution problem in a particular area. PM2.5 Precursor 
Guidance at 18.
    In addition, we note that the EPA has previously made significance 
determinations in the context of section 213 of the CAA, related to 
certain stages of decisions regarding regulation of new nonroad engines 
and vehicles. CAA section 213 is the only provision of the CAA, apart 
from CAA section 111(b)(1), where Congress employed the modifier 
``significantly'' in connection with language directing the 
Administrator to determine if air pollutant emissions from new and 
existing (in the case of emissions of CO, NOX, and VOCs) 
nonroad engines and vehicles in the aggregate ``contribute'' to ``air 
pollution which may reasonably be anticipated to endanger public health 
or welfare,'' in CAA sections 213(a)(1), (2) and (4), before then 
directing and authorizing the EPA to promulgate standards applicable to 
classes and categories of just new nonroad engines and vehicles that 
emit pollutants contributing (without employing a ``significance'' 
modifier) to such air pollution under CAA sections 213(a)(3) and (4). 
When the EPA first undertook rulemaking as directed by CAA section 213, 
it noted that ``[s]ection 213(a) . . . provides no guidance as to what 
constitutes a `significant' contribution.'' See 58 FR 28811 (May 17, 
1993). Thus, the EPA looked to ``the legislative history and the scope 
of the [1990 CAA Amendments], the emission contribution of nonroad 
engines and vehicles, and a comparison of nonroad emissions to 
emissions from other regulated sources'' in proposing to find that 
emissions from nonroad sources were indeed ``significant.'' Id.
    In taking final action to promulgate the initial set of new nonroad 
engine and vehicle standards, the EPA responded to commenters who had 
``argued that EPA cannot make a significance determination without 
first defining a standard upon which to base that determination.'' See 
59 FR 31308 (June 17, 1994). The EPA did not disavow the need to 
justify a finding that contributions were significant, but it did 
object to the commenters' apparent assertion that a ``specific 
numerical standard for significance must be determined prior to 
considering whether nonroad emissions are significant.'' Id. (emphasis 
added). The EPA noted that Congress in CAA section 213 ``gave EPA wide 
discretion to determine whether the emissions of NOX, VOC, 
and CO from nonroad engines and vehicles are significant contributors 
to ozone or CO concentrations,'' and then pointed to the qualitative 
assessment the EPA had made based on the criteria it had identified in 
the proposed rule. Id.
    Based on the reasoning of the caselaw described above and 
consistent with the EPA's approach for similar CAA provisions, the EPA 
believes that ``contributes significantly'' under CAA section 
111(b)(1)(A) is ambiguous, but that Congress has made clear that in 
order to be subject to regulation, the emissions must have a greater 
impact than a simple contribution. It is within the Agency's discretion 
to identify additional qualitative or quantitative criteria or 
factors--ones that are related to the nature of the air pollutant, the 
source category, and the air pollution problem at issue--to determine 
whether a contribution is ``significant,'' as long as the Agency 
provides a reasoned basis to justify using such additional criteria or 
factors.\83\ The EPA solicits comment on whether the examples discussed 
above, in which the EPA has construed

[[Page 50269]]

and applied statutory language similar to the term ``contributes 
significantly'' in CAA section 111(b)(1)(A), \84\ suggest factors that 
it may be appropriate for the EPA to consider when construing and 
applying that term in the context of CAA section 111, including, but 
not limited to, whether the consideration of cost-effectiveness in the 
interstate transport context may suggest that the EPA should or has 
discretion to consider whether CAA section 111(b) provides a cost-
effective basis to assess a source category's contribution to a 
particular air-pollution problem as part of the EPA's determination 
whether that source category significantly contributes to that air 
pollution problem.
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    \83\ See PM2.5 Precursor Guidance at 12.
    \84\ In this solicitation of comment, the EPA is not soliciting 
comment on, or re-opening, any aspect of the rulemakings that 
contained those examples.
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2. Elements of Criteria for Significant Contribution Finding Under CAA 
Section 111
    First, the EPA solicits comment on what information the Agency 
should consider when quantifying the emissions of the pollutant in 
question from the source category. In section VI.C.3, we detail the 
historical, current, and projected methane emissions from various 
source categories. To what extent should the SCF rely primarily on the 
most recent emission inventories, and to what extent should historical 
trends and future projections inform the Administrator's finding? For 
example, consider the case of minimal current day emissions, but 
projections of rapid emission growth; or, conversely, substantial 
current emissions, but projections of a rapid decline in emissions even 
in the absence of new rulemakings. In turn, should the SCF evaluate the 
significant contribution of new sources potentially subject to 
regulation under CAA section 111(b) as well as existing sources 
potentially subject to subsequent regulation under CAA section 111(d)? 
\85\ Similarly, for a source category in which new sources are not 
expected in the future, should the Administrator independently evaluate 
significant contribution from existing sources? Finally, in the case of 
the 2016 NSPS OOOOa rule, should the EPA consider only methane 
emissions or also account for CO2 emissions and any other 
GHG that may be emitted from the source category?
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    \85\ To date, the EPA has evaluated the emissions from the 
source category, which includes existing sources, in making the SCF 
determination, and the D.C. Circuit has upheld that industry-wide 
approach. See Nat'l Lime Ass'n v. EPA, 627 F.2d 416, 433 n.48 (D.C. 
Cir. 1980); Nat'l Asphalt Pavement Ass'n v. Train, 539 F.2d 775, 
779-82 (D.C. Cir. 1976).
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    Second, the EPA is soliciting comment on the total universe of 
emissions to which the emission of the pollutant in question from the 
source category in question should be compared. If the source category 
emits primarily a single gas (e.g., methane), should the emissions from 
that source category be compared against methane emissions (see Table 
7, column 3 of this preamble) or against all GHG emissions (see Table 
7, column 4 of this preamble)? How should natural emissions be 
considered in this comparison (see VI.C.3.a.i of this preamble)? Should 
the comparison be to domestic emissions (see Table 7 of this preamble) 
or to global emissions (see Table 8 of this preamble)? Or should 
multiple comparisons be made, as in VI.C.3 of this preamble? In making 
a SCF, should the Administrator evaluate the efficacy of regulation for 
new and/or existing sources? The EPA also welcomes comment on 
appropriate and well-vetted sources to use for domestic, global, and 
natural emissions.
    Third, the EPA is soliciting comment on whether the Administrator 
should determine a threshold for significant contribution under CAA 
section 111(b)(1)(A) (above which, the emissions of the pollutant from 
the source category would be determined to significantly contribute, 
and below which, they would not), and which factors the Administrator 
should consider in determining that threshold. Is there a simple 
percentage criterion that holds across pollutants and source categories 
(i.e., a source category responsible for X percent of any pollutant is 
deemed to ``significantly contribute'' to the air pollution caused by 
that pollutant), or would it depend on, for example, the number of 
source categories that emit that pollutant (and the relative emissions 
from the source category whose emissions are the subject of the SCF 
determination in question, as compared to emissions from those other 
source categories); the nature of the pollutant; and/or the nature of 
the air pollution to which that pollutant may contribute (i.e., should 
the EPA address the question whether emissions of criteria and other 
traditional air pollutants, which cause air pollution primarily due to 
direct exposure, ambient regional concentration, and/or intermediate-
range transport, ``significantly contribute'' to air pollution in a 
different manner than it should address the question whether emissions 
of GHG ``significantly contribute'' to climate change)?
    Finally, the EPA is soliciting comment on the implications of the 
fact that methane in the atmosphere serves as a precursor to 
tropospheric ozone, as noted in previous EPA rules (see 81 FR 35837). 
Are there legal implications resulting from this contribution of 
methane to a criteria pollutant? For example, as discussed above, the 
EPA is proposing that the regulation of VOC from new sources under CAA 
section 111(a) does not trigger the application of CAA section 111(d) 
to existing sources in the same source category because VOC are a 
precursor to tropospheric ozone.\86\ Does the fact that methane is also 
a precursor to ozone indicate that regulation of methane from new 
sources under CAA section 111(b) would not trigger the application of 
CAA section 111(d) to existing sources in the same source category for 
the same reason? If EPA is precluded from regulating existing sources 
of a pollutant under CAA section 111(d), should that factor be 
evaluated in a SCF? What considerations are relevant for pollutants 
that contribute to multiple different kinds of pollution (methane as 
both a GHG and an ozone precursor, CO2 as both a GHG and a 
contributor to ocean acidification, NOX as a precursor to 
both PM2.5 and ozone)? In this regard, the EPA notes that 
the definition of ``air pollutant'' at CAA section 302(g) provides that 
the term ``includes any precursors to the formation of any air 
pollutant, to the extent the Administrator has identified such 
precursor or precursors for the particular purpose for which the term 
`air pollutant' is used.''
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    \86\ It is worth noting that while EPA has excluded methane and 
some related pollutants from the definition of VOC, methane is 
chemically a VOC.
---------------------------------------------------------------------------

    The Agency welcomes comments on any and all aspects of these 
questions.
3. Background Concerning Methane and GHG Emissions
    a. Methane Emissions
    i. Natural and anthropogenic emissions of methane. Methane is 
emitted from a variety of natural and anthropogenic sources and 
activities. Globally, it is estimated that around 60 percent of methane 
emissions are from anthropogenic activities, and 40 percent are from 
natural activities (Saunois et al., 2016). Anthropogenic sources 
include natural gas and petroleum systems, enteric fermentation, solid 
waste disposal, coal mining, and other sources. Natural sources include 
wetlands, natural biomass burning, geologic seepage, termites, oceans, 
and permafrost.
    In a 2018 report, the National Academy of Sciences noted a number 
of complex factors related to methane that

[[Page 50270]]

may be relevant to a pollutant-specific SCF for domestic oil and 
natural gas production, processing, transmission, or storage:

    Methane comes from numerous anthropogenic activities and natural 
processes (Figure 1.3), and notably, there is no single dominant 
source, but rather many significant sources. This configuration of 
sources forces a broader view of emissions for this gas, as opposed 
to many other significant GHGs whose anthropogenic sources tend to 
be dominated by a single source type such as from the combustion of 
fossil fuel.
    The U.S. methane budget (emissions and removal processes) cannot 
be considered in isolation from the global methane budget because 
U.S. emissions account for only about one-tenth of global emissions. 
Consequently, atmospheric methane abundance over the United States 
is significantly influenced by sources located outside of the United 
States, even though there may be large responses due to strong local 
emissions. The atmospheric residence time for methane is about a 
decade; hence emitted methane is redistributed globally, and methane 
emissions from the United States influence global concentrations.
    About 60 percent of total global methane emissions are thought 
to be from anthropogenic sources and about 40 percent from natural 
sources (Saunois et al., 2016). Anthropogenic sources encompass a 
wide range of human activities, including food and energy production 
and waste disposal. Livestock (through fermentation processes in 
their digestive system that generate methane and manure management), 
rice cultivation, landfills, and sewage account for 55-57 percent of 
global anthropogenic emissions. Emissions from production of fossil 
fuels, including petroleum, natural gas, and coal, are estimated to 
account for 32-34 percent (Saunois et al., 2016), with the remainder 
from biomass, biofuel burning, and minor industrial processes.\87\
---------------------------------------------------------------------------

    \87\ Improving Characterization of Anthropogenic Methane 
Emissions in the United States (2018), https://www.nap.edu/read/24987/chapter/3#26.

    Global atmospheric methane concentrations have increased by about 
164 percent since 1750, from a pre-industrial value of about 700 parts 
per billion (ppb) to 1,849 ppb in 2017 (National Oceanic and 
Atmospheric Administration (NOAA)/Earth System Research Laboratory 
(ESRL), 2018).
    In section III.A.2.a, Table 2 presents total U.S. anthropogenic 
methane emissions for the years 1990, 2008, and 2017. In the U.S., the 
largest anthropogenic sources of methane are natural gas and petroleum 
systems, enteric fermentation, and landfills. Methane emissions are 10 
percent of total U.S. GHG emissions in CO2 equivelent. 
Methane emissions have decreased by 15 percent since 1990, and by 7 
percent since 2008. Table 3 above presents total methane emissions from 
natural gas and petroleum systems, and the associated segments of the 
sector, for years 1990, 2008, and 2017, in MMT CO2 Eq.
    ii. Trends. As seen in Figure 1, methane emissions from the oil and 
natural gas production, natural gas processing, and natural gas 
transmission and storage segments together decreased by 2 percent 
between 2008 and 2017. Methane emissions from the production and 
processing segments together decreased by 3 percent over the same time 
period, while methane emissions from transmission and storage increased 
by 1 percent. These trends also took place during periods of 
substantial increases in oil and natural gas production.
[GRAPHIC] [TIFF OMITTED] TP24SE19.000

    Oil and natural gas production segment trends are impacted by 
decreases in oil and natural gas exploration emissions (91 percent from 
2008 to 2017), primarily due to decreases in hydraulically fractured 
well completions without RECs and a decrease in the number of well 
completions. Production emissions outside of the exploration 
subcategory increased by 8 percent over the time frame, primarily due 
to increased emissions from gathering and boosting stations. In the 
processing segment, emissions increased by 9 percent over

[[Page 50271]]

the time period, due primarily to an increase in emissions from 
compressor engine exhaust, caused by an increase in engine capacity per 
plant. Over the same time frame, oil production increased 35 percent 
and natural gas production increased 87 percent.
    The increase in methane emissions in the transmission and storage 
segment from 2008-2017 was driven by an increase in emissions from 
compressor engine exhaust and station venting. Over the same time 
frame, natural gas consumption increased by 16 percent.
    iii. Projections. According to the latest Energy Information 
Administration (EIA) Annual Energy Outlook report,\88\ from 2017 to 
2050, dry natural gas and crude oil and lease condensate production 
(which impact the production and processing segments emissions) are 
projected to increase by 60 percent and 26 percent, respectively, while 
natural gas consumption (which impacts transmission and storage 
emissions) is projected to grow by 29 percent.
---------------------------------------------------------------------------

    \88\ https://www.eia.gov/outlooks/aeo/data/browser/#/?id=1-AEO2019&cases=ref2019&sourcekey=0. Reference scenario. Accessed 
April 12, 2019.
---------------------------------------------------------------------------

    b. U.S. oil and natural gas production and natural gas processing 
and transmission and storage GHG emissions relative to total U.S. GHG 
emissions.\89\ Relying on data from the U.S. GHGI, we compared U.S.: 
(1) Oil and natural gas production and natural gas processing and 
transmission GHG emissions, (2) oil and natural gas processing GHG 
emissions; and (3) transmission and storage GHG emissions to total U.S. 
GHG emissions as an indication of the role these segments play in the 
total domestic contribution to the air pollution that is causing 
climate change. In 2017, total U.S. GHG emissions from all sources were 
6,472 MMT CO2 Eq.
---------------------------------------------------------------------------

    \89\ The U.S. and global figures in this subsection refer to 
anthropogenic emissions.

         Table 7--Comparisons of U.S. Oil and Natural Gas Emissions to Total United States GHG Emissions
----------------------------------------------------------------------------------------------------------------
                                                              2017 CH4
                                                           emissions (MMT     Share of total     Share of total
                                                              CO2 eq)          U.S. CH4 (%)       U.S. GHG (%)
----------------------------------------------------------------------------------------------------------------
U.S. Oil & Gas Production and Natural Gas Processing &                 190                 29                  3
 Transmission and Storage..............................
U.S. Oil & Gas Production and Natural Gas Processing...                158                 24                  2
U.S. Gas Transmission and Storage......................                 32                  5                  1
----------------------------------------------------------------------------------------------------------------
Emissions from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2017 (published April 11, 2019),
  calculated using methane (CH4) GWP of 25.

    c. U.S. oil and natural gas production and natural gas processing 
and transmission and storage GHG emissions relative to total global GHG 
emissions. For additional background information and context, we used 
2014 emissions data from the World Resources Institute (WRI) to make 
comparisons between U.S. oil and natural gas production and natural gas 
processing and transmission and storage (and subsets thereof) emissions 
and the emissions inventories of entire countries and regions.

        Table 8--Comparisons of United States Oil and Natural Gas Emissions to Total Global GHG Emissions
----------------------------------------------------------------------------------------------------------------
                                                              2014 CH4
                                                           emissions (MMT    Share of global    Share of global
                                                              CO2 eq)            CH4 (%)            GHG (%)
----------------------------------------------------------------------------------------------------------------
U.S. Oil & Gas Production and Natural Gas Processing &                 194                2.1                0.4
 Transmission and Storage..............................
U.S. Oil & Gas Production and Natural Gas Processing...                162                1.8                0.3
U.S. Gas Transmission and Storage......................                 32                0.4                0.1
----------------------------------------------------------------------------------------------------------------
Emissions from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2017 (published April 11, 2019),
  calculated using CH4GWP of 25.
Note: Totals may not sum due to rounding.

    Recent trends in global GHG emissions suggest that the proportion 
of U.S. methane emissions, including emissions from oil and natural gas 
production, processing, transmission, and storage, is likely to 
represent a smaller share in the future.

VII. Implications for Regulation of Existing Sources

    The EPA recognizes that by rescinding the applicability of the 
NSPS, issued under CAA section 111(b), to methane emissions for the 
sources in the Crude Oil and Natural Gas Production source category 
that are currently covered by the NSPS, existing sources of the same 
type in the source category will not be subject to regulation under CAA 
section 111(d). The EPA discusses the implications of this and other 
relevant issues below. In subsection A below, we explain our legal 
interpretation of CAA section 111(d)(1) and propose that promulgating 
an NSPS for VOC emissions from new sources in the Crude Oil and Natural 
Gas Production source category under CAA section 111(b) does not 
trigger the application of CAA section 111(d) existing sources in the 
source category. In subsection B below, we explain why the lack of 
regulation of existing sources under CAA section 111(d) will not mean a 
substantial amount of lost emission reductions. That is because we 
expect that many existing sources will retire or become subject to 
regulation under CAA section 111(b) because they will undertake 
modification or reconstruction. In addition, existing sources already 
have market incentives to reduce methane emissions, participate in 
voluntary programs to do so, and in many cases are subject to state 
requirements to do so.

[[Page 50272]]

A. Existing Source Regulation Under CAA Section 111(d)

    CAA section 111(d) authorizes the regulation of existing sources in 
a source category for particular air pollutants to which a standard of 
performance would apply if those existing sources were new sources. By 
legal operation of the terms of CAA section 111(d), certain existing 
sources in the Crude Oil and Natural Gas Production source category 
will no longer be subject to regulation under CAA section 111(d) as a 
result of this proposed rule. Under CAA section 111(d)(1)(A), CAA 
section 111(d) applies only to air pollutants for which air quality 
criteria have not been issued, which are not on the EPA's list of air 
pollutants issued under CAA section 108(a) (generally, the list of air 
pollutants subject to the NAAQS, and which are not HAP emitted from a 
source category regulated under CAA section 112. See 42 U.S.C. 
7411(d)(1)(A) (CAA section 111(d) applies to ``any air pollutant (i) 
for which air quality criteria have not been issued or which is not 
included on a list published under section 7408(a) of this title or 
emitted from a source category which is regulated under section 7412 of 
this title''). As noted above, sources in the Crude Oil and Natural Gas 
Production source category emit VOC, methane, and HAP. The CAA section 
112 exclusion in CAA section 111(d)(1)(A) eliminates HAP from the type 
of air pollutant that, if subjected to a standard of performance for 
new sources, would trigger the application of CAA section 111(d). In 
addition, as discussed below, the EPA proposes that VOC do not qualify 
as the type of air pollutant that, if subjected to a standard of 
performance for new sources, would trigger the application of CAA 
section 111(d). On the other hand, the EPA has, to date, assumed that 
methane, if subjected to a standard of performance for new sources, 
would trigger the application of CAA section 111(d). Accordingly, given 
this assumption, the EPA recognizes that rescinding the applicability 
of the NSPS to methane emissions for the sources in the Crude Oil and 
Natural Gas Production source category that are currently covered by 
the NSPS will mean that existing sources of the same type in the source 
category will not be subject to regulation under CAA section 111(d). 
This is a legal consequence that results from the application of the 
CAA section 111 requirements.
    Further, VOC do not qualify as the type of air pollutant that, if 
subjected to a standard of performance for new sources, would trigger 
the application of CAA section 111(d). As noted above, the pollutants 
excluded from regulation under CAA section 111(d) include pollutants 
which have been included on the EPA's CAA section 108(a) list. VOC are 
not expressly listed on the EPA's section CAA section 108(a) list, but 
they are precursors to ozone and PM, both of which are listed CAA 
section 108(a) pollutants. The definition of ``air pollutant'' in CAA 
section 302(g) expressly provides that the term ``air pollutant'' 
includes precursors to the formation of an air pollutant ``to the 
extent that the Administrator has identified such precursor or 
precursors for the particular purpose for which the term `air 
pollutant' is used.'' Based on this ``particular purpose'' phrasing, it 
is appropriate to identify VOC as a listed CAA section 108(a) pollutant 
for the particular purpose of applying the CAA section 108(a) exclusion 
in CAA section 111(d) for the following reasons: first, VOC are 
regulated under the CAA's NAAQS/SIP program as a result of the listing 
of ozone and PM on the CAA section 108(a) list, because VOC are 
precursors to those two listed pollutants. Indeed, ozone levels in the 
ambient air are the result of photochemical reactions of precursors 
(VOC and NOX), as opposed to being directly emitted from sources. 
Accordingly, the statutory provisions directed at attaining the NAAQS 
for ozone explicitly direct the control of VOC and emissions controls 
that result from the listing of ozone under CAA section 108(a) apply to 
the precursors of ozone, such a VOC. See, e.g., CAA sections 182(b)(1), 
182(b)(2), 182(c)(2)(B). Similarly, the EPA has recognized that ``[i]n 
most areas of the country, PM2.5 precursors are major 
contributors to ambient PM2.5 concentrations.'' 73 FR 28321, 
28325/2 (May 16, 2008). In such areas of the country, VOC are, thus, 
controlled for purposes of reducing ambient PM2.5 
concentrations. See, e.g., U.S. EPA, Office of Air Quality Planing and 
Standards, ``Guidance on Significant Impact Levels for Ozone and Fine 
Particles in the Prevention of Significant Deterioration Permitting 
Program,'' April 17, 2018.
    Second, excluding VOC from regulation under CAA section 111(d) 
makes sense within the CAA's three-part structure for addressing 
emissions from stationary sources. As the EPA has discussed in past 
rulemakings, the CAA--sets out a comprehensive scheme for air pollution 
control, addressing three general categories of pollutants emitted from 
stationary sources: (1) Criteria pollutants (which are addressed in CAA 
sections 108-110); (2) hazardous pollutants (which are addressed under 
CAA section 112); and (3) ``pollutants that are (or may be) harmful to 
public health or welfare but are not or cannot be controlled under 
sections 108-110 or 112.'' ``Carbon Pollution Emission Guidelines for 
Existing Stationary Sources: Electric Utility Generating Units: Final 
Rule,'' 80 FR 64661, 64711 (October 23, 2015) (quoting 40 FR 53340 
(November 17, 1975)). Within this three-part structure, CAA section 
111(d) is properly understood as a ``gap-filling'' measure to address 
pollutants that are not addressed under either the NAAQS/SIP provisions 
in CAA sections 108-110 or the HAP provisions in CAA section 112. 
Because VOC are regulated as precursors to ozone and PM2.5 
under CAA sections 108-110, they are properly excluded from regulation 
under CAA section 111(d) because the ``gap-filling'' function of CAA 
section 111(d) is not needed.
    Third, reading the phrase ``included on a list published under [CAA 
section 108(a)]'' as including precursors is consistent with the 
provision in CAA section 112(b)(2) that restricts what pollutants may 
be listed as CAA section 112 HAP. CAA section 112(b)(2) provides, in 
pertinent part:

    No air pollutant which is listed under section 7408(a) of this 
title may be added to the list under this section, except that the 
prohibition of this sentence shall not apply to any pollutant which 
independently meets the listing criteria of this paragraph and is a 
precursor to a pollutant which is listed under section 7408(a) of 
this title or to any pollutant which is in a class of pollutants 
listed under such section.

The ``except'' phrasing of this sentence suggests that air pollutants 
which are ``listed under section 7408(a)'' can be read to include 
precursors to the pollutant that is listed under CAA section 108(a). 
Otherwise, pollutants that are described in the second part of the 
sentence (pollutants that meet the listing criteria and are precursors 
to a CAA section 108(a) pollutant) would not be an exception to the 
prohibition in the first part of the sentence.
    Finally, the fact that precursors are not always treated as CAA 
section 108(a) listed pollutants under all contexts across the CAA does 
not undermine the conclusion that they should be excluded under the CAA 
section 108(a) exclusion in CAA section 111(d). As the CAA section 
302(g) definition expressly states, the scope of ``air pollutant'' is 
considered based on the ``particular purpose'' for which the term ``air 
pollutant'' is used. The EPA

[[Page 50273]]

has long recognized that the ``particular purpose'' clause in CAA 
section 302(g) ``indicates that the Administrator has discretion to 
identify which pollutants should be classified as precursors for 
particular regulatory purposes.'' 73 FR 28326/1 (May 16, 2008) (``Thus, 
we do not necessarily construe the Act to require that the EPA identify 
a particular precursor as an air pollutant for all regulatory purposes 
where it can be demonstrated that various programs under the Act 
address different aspects of the air pollutant problem. Likewise, we do 
not interpret the Act to require that the EPA treat all precursors of a 
particular pollutant the same under any one program when there is a 
basis to distinguish between such precursors within that program.'').

B. Limited Impact of Lack of Regulation of Existing Oil and Gas Sources 
Under CAA Section 111(d)

    In this subsection, we explain the several reasons why the lack of 
regulation of existing sources under CAA section 111(d) will have 
limited environment impact.
1. Potential Applicability of 40 CFR Part 60, Subpart OOOOa to Current 
Existing Sources
    The EPA notes that the 2016 NSPS OOOOa rule includes a definition 
and approach to determining new source applicability that is very 
broad, and in the specific context of the oil and natural gas 
production industry, can be anticipated to result in wide applicability 
of the NSPS to existing sources due to the frequency with which such 
sources can be reasonably expected to engage in ``modification'' 
activity. One consequence is the expected reduction of methane 
emissions from existing sources notwithstanding the proposed 
alternative actions set forth here. Further, the EPA believes that it 
is reasonable to expect that the number of existing sources may decline 
over time due to obsolescence or to shut down and removal actions, 
which would mitigate the environmental impacts of lack of direct 
existing source regulation under CAA section 111(d), and as noted 
below, the EPA is soliciting comment to determine the rate at which 
this decline can be expected to occur.
    The EPA is in the process of examining the rate of turnover of 
existing facilities, including the rate at which existing facilities 
are replaced with new facilities, are modified, or shut down. The EPA 
has reviewed indirect turnover information from three different 
sources. First, the EPA assessed the GHGI to identify the activity 
counts for pneumatic controllers, compressors, tank throughput, and 
well completions.\90\ Second, the EPA reviewed activity counts from 
DrillingInfo for well completions.\91\ Third, the EPA reviewed a number 
of compliance reports for the approximate first reported compliance 
year since the promulgation of the 2016 NSPS OOOOa rule. The EPA 
determined that the available information may be indicative of trends 
for some sources whereas, for other sources, no conclusions can yet be 
drawn. The following section presents the information available to the 
EPA from which it appears possible to identify trends. We solicit 
information and data to help evaluate the rate at which existing 
sources decline over time, through modification, obsolescence, 
shutdown, replacement to new source status or otherwise. Specifically, 
we are requesting information regarding affected facility useful life 
in hours or years (i.e., expected years of operation before 
replacement) and affected facilities that commenced new construction, 
modification, or reconstruction over a time period (e.g., 2016, 2017, 
and 2018). The following paragraphs present the information currently 
available to the EPA by source.
---------------------------------------------------------------------------

    \90\ The GHGI includes national estimates of various types of 
activity data, some of which correspond approximately to the 2016 
NSPS OOOOa facility categories. The EPA looked at the change in 
facilities between 2011 and 2017 in order to isolate the effect of 
the 2012 NSPS OOOO rule to understand turnover of affected 
facilities. The EPA recognizes uncertainty in this use of data from 
the GHGI and the EPA will need additional information to assess the 
identified data gaps for purposes of identifying trends.
    \91\ The DrillingInfo database includes information on oil and 
natural gas wells, production, well completions, and associated 
data. This is relevant to potential turnover for purposes of well 
completion and fugitive emissions requirements. DrillingInfo records 
show the extent to which currently producing wells have had a 
completion in recent years, or the ratio of completions to total 
producing wells. The EPA recognizes uncertainty in data from this 
source and will need additional information to assess the identified 
data gaps for purposes of identifying trends.
---------------------------------------------------------------------------

    a. Pneumatic controllers. The count of high-bleed pneumatic 
controllers in the oil and natural gas production segment declined 74 
percent from 2011 to 2017. The count of low-bleed pneumatic controllers 
also declined (by 41 percent), while intermittent-bleed increased (by 
52 percent). Over the same period, the overall count of pneumatic 
controllers in this segment decreased by 3 percent. This indicates that 
high-bleed and low-bleed controllers have been replaced by intermittent 
bleed controllers. The rapid pace at which high- and low-bleed 
controllers declined while intermittent-bleed controllers increased 
suggests that pneumatic controllers had a high rate of turnover or were 
replaced before the end of their useful life. This data shows a 
relatively small number of remaining existing high-bleed pneumatic 
controllers relative to a few years ago. The EPA solicits data and 
information on the turnover rate of pneumatic controllers.
    b. Compressors. The count of wet seal centrifugal compressors at 
processing plants was 343 in both 2011 and 2017.\92\ The EPA expects 
the dry seal control option to be the most common control strategy due 
to its low cost. For comparison, the number of dry seal compressors at 
processing plants changed from 281 to 339 (or 21 percent), an increase 
of 58. At the same time the number of processing plants increased by 
61. The EPA solicits data and information on the turnover rate of wet 
seal centrifugal compressors.
---------------------------------------------------------------------------

    \92\ New or modified wet seal centrifugal compressors are 
subject to control requirement under NSPS OOOO and OOOOa while dry 
seal centrifugal compressors are not.
---------------------------------------------------------------------------

    c. Storage vessels. Natural gas production throughput at large 
condensate storage vessels without controls decreased by 33 percent 
from 2011 to 2017. The growth is slower than the growth in natural gas 
production throughput of all other types of condensate storage vessels 
(large tanks with flares and vapor recovery units (VRU), and small 
tanks with and without flares), which was 41 percent. Oil production 
throughput at large storage vessels without controls increased by 18 
percent from 2011 to 2017. The growth is slower than the growth in oil 
production throughput of all other types of storage vessels (large 
tanks with flares and VRUs, and small tanks with and without flares), 
which was 92 percent. In general, if many existing storage vessels were 
being replaced, becoming subject to 2016 NSPS OOOOa and then installing 
controls, we may expect production throughput at large uncontrolled 
storage tanks to decline, with corresponding increases at controlled 
tanks. The EPA solicits data and information on storage vessel 
production throughput and the turnover rate of affected facilities.
    d. Well completions. Based on the GHGI, the ratio of natural gas 
well completions to total producing natural gas wells from 2011 to 2017 
has decreased, from 2.4 to 1.1 percent. The ratio of oil well 
completions to total producing oil wells has remained at approximately 
3 percent from 2011 to 2017. If wells had a relatively short

[[Page 50274]]

production lifetime, we would expect a high ratio of completions to 
total producing wells. The 2 percent ratio indicates that a relatively 
small number of wells are completed each year. Based on a preliminary 
analysis of the DrillingInfo database, approximately one-third of total 
producing oil and gas wells in 2014 had a completion in the prior 10 
years, while two-thirds of producing oil and gas wells had no 
completion records for at least 10 years. If the EPA assumes that 
future completion activity follows these trends, then after 2016 NSPS 
OOOOa well site fugitive requirements have been in place for 10 years 
(2016 through 2025), we might expect completions at about one-third of 
wells (from the perspective of having had a completion after the 
effective date of the 2016 NSPS OOOOa). The EPA solicits data and 
information regarding the proportion of wells that have undergone a 
completion during a shorter time period (e.g., less than 10 years) and 
that would imply that most well sites are subject to 2016 NSPS OOOOa. 
The EPA solicits comment on how we should characterize wells sharing 
well sites (e.g., if only half of wells have had a recent completion, 
it would be possible for half the wells to not be subject to 2016 NSPS 
OOOOa, or potentially all wells could be subject to 2016 NSPS OOOOa, if 
wells without a recent completion always share a well site with newer 
wells).
    e. Compliance reports. The EPA reviewed all NSPS OOOOa compliance 
reports that had been submitted to the Agency through November 21, 
2017, in order to identify information to use to develop a rate at 
which existing facilities become new or modified.\93\ Information in 
these compliance reports indicates the number of various types of 
facilities subject to the NSPS during the given time range. The reports 
included 2,991 well sites, encompassing 697 storage vessels, five 
pneumatic controllers, 663 pneumatic pumps, and 2,091 instances of 
fugitive emissions monitoring. 130 compressor stations were included in 
the reports, encompassing 148 reciprocating compressors and 94 
instances of fugitive emissions monitoring. In addition, 38 natural gas 
processing plants were included, encompassing one pneumatic controller 
and 32 reciprocating compressors. The reports included both new and 
existing facilities, which we can disaggregate in part by subtracting 
our previous estimates of the number of ``new'' facilities from these 
counts which include both new and modified. A high rate of turnover 
(e.g., a high rate of facilities performing modification(s) which 
caused them to become subject to the 2016 NSPS OOOOa) would imply that 
a large number of facilities should be submitting compliance reports. 
Thus, the general proportions of the number of facilities in the 
compliance reports versus the total population indicates how quickly 
facilities became subject to the NSPS during this period. Due to 
various uncertainties, we are unable to develop a rate at which 
existing sources become subject to the NSPS OOOOa. The EPA solicits 
comment on ways to use this information to predict turnover trends.
---------------------------------------------------------------------------

    \93\ These reports have since been made available for public 
viewing at https://www.foiaonline.gov/foiaonline/action/public/submissionDetails?trackingNumber=EPA-HQ-2018-001886&type=request.
---------------------------------------------------------------------------

    The EPA has also considered multiple factors unrelated to federal 
regulatory requirements that achieve methane emissions reductions. 
First, market incentives exist for the oil and natural gas industry to 
capture as much of its primary product as is cost effective, and that 
capture reduces methane emissions. Second, firms in the oil and natural 
gas industry participate in several voluntary programs to reduce 
emissions. Third, many of the top oil and natural gas-producing states 
have developed or are developing regulations that require emissions 
reductions. We believe these factors also should be considered for the 
universe of existing facilities and that they point away from any need 
to regulate existing sources under CAA section 111(d). The EPA presents 
below background information and data on each of these factors.
2. Market Incentives
    As methane is the primary constituent of natural gas, an important 
commodity, operators have market incentives to reduce emissions and the 
loss of valuable product to the atmosphere. Absent regulation, the 
incentive to maximize the capture of natural gas is the market price 
obtained by the operator producing the natural gas. Assuming 
financially rational-acting producers, standard economic theory 
suggests that oil and natural gas operators will incorporate all cost-
effective production improvements of which they are aware without 
government intervention. Depending on the future trajectories of 
natural gas prices and the costs of natural gas capture, these market 
incentives speak to the question of whether, even in the absence of 
specific regulatory requirements applicable to methane emissions from 
existing sources, meaningful emission decreases can nevertheless be 
projected to occur.
    As shown in Figure 2 below, as technology, expertise, 
infrastructure, and regulation in the oil and natural gas industry has 
improved, less natural gas has been lost to unproductive uses such as 
venting and flaring. Figure 2 shows how the gross withdrawals \94\ of 
natural gas has generally increased in the U.S. over the past 80 years 
while the fraction of this withdrawn natural gas lost to venting and 
flaring has generally been decreasing over the same time frame.
---------------------------------------------------------------------------

    \94\ U.S. EIA defines gross withdrawals of natural gas as 
``[f]ull well-stream volume, including all-natural gas plant liquids 
and all nonhydrocarbon gases, but excluding lease condensate. Also 
includes amounts delivered as royalty payments or consumed in field 
operations.'' Available at: https://www.eia.gov/dnav/ng/TblDefs/ng_sum_sndm_tbldef2.asp. Accessed October 30, 2018.

---------------------------------------------------------------------------

[[Page 50275]]

[GRAPHIC] [TIFF OMITTED] TP24SE19.001

    In 2004, the Government Accountability Office (GAO) noted that the 
venting and flaring data collected by the U.S. EIA was limited in 
several ways, including that the data is voluntarily and inconsistently 
reported.\96\ With that caveat in mind, while this figure does not 
depict a precise relationship between natural gas production and 
methane emissions, the figure highlights the point that the productive 
inefficiency of losing natural gas to venting and flaring has been 
reduced greatly over this long period of time, likely the product of 
operators learning to improve returns on costly drilling and production 
investments by capturing more of the product coming out of the ground, 
as well as to improve the health, safety, and environmental performance 
of their operations.
---------------------------------------------------------------------------

    \95\ U.S. EIA data on natural gas gross withdrawals available 
at: https://www.eia.gov/dnav/ng/ng_prod_sum_a_EPG0_FGW_mmcf_a.htm. 
Accessed October 30, 2018. U.S. EIA data on vented and flared 
natural gas available at: https://www.eia.gov/dnav/ng/ng_prod_sum_a_EPG0_VGV_mmcf_a.htm. Accessed October 30, 2018.
    \96\ Available at: https://www.gao.gov/assets/250/243433.pdf. 
Accessed October 30, 2018.
---------------------------------------------------------------------------

    Regarding the relationship of methane emissions and natural gas 
production, while overall natural gas gross withdrawals have increased 
about 50 percent from 1990 to 2016, aggregate methane emissions from 
the NSPS OOOOa-relevant industry segments have stayed relatively flat 
(Figure 3). This trend indicates decreasing aggregate methane emissions 
intensity for these segments over this period (Figure 3).

[[Page 50276]]

[GRAPHIC] [TIFF OMITTED] TP24SE19.002

    The  EPA solicits comment on whether sufficient market incentives 
exist to offset the costs of emissions capture such that total methane 
emissions will trend downward under these incentives.
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    \97\ Methane emissions from Table 3.5-2 (Petroleum Systems) and 
Table 3.6-1 (Natural Gas Systems) in U.S. EPA. 2018. Inventory of 
U.S. Greenhouse Gas Emissions and Sinks: 1990-2016. EPA 430-R-18-
003. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2016. Accessed October 31, 
2018. U.S. EIA data on natural gas gross withdrawals available at: 
https://www.eia.gov/dnav/ng/ng_prod_sum_a_EPG0_FGW_mmcf_a.htm. 
Accessed October 31, 2018.
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3. Voluntary Programs
    Separate from regulatory requirements, owners and operators of 
facilities in the oil and natural gas industry participate in voluntary 
programs that reduce their methane emissions. Specifically, many owners 
and operators of facilities participate in the EPA partnership programs 
Natural Gas STAR Program and the Methane Challenge Program. Owners and 
operators also participate in voluntary programs unaffiliated with the 
EPA voluntary programs, such as the Environmental Partnership \98\ and 
the Climate and Clean Air Coalition (CCAC) Oil & Gas Methane 
Partnership. Firms might participate in voluntary environmental 
programs for a variety of reasons, including attracting customers, 
employees, and investors who value more environmental-responsible goods 
and services; finding approaches to improve efficiency and reduce 
costs; and reducing pressures for potential new regulations or helping 
shape future regulations.99 100
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    \98\ https://theenvironmentalpartnership.org/.
    \99\ Borck, J.C. and C. Coglianese (2009). ``Voluntary 
Environmental Programs: Assessing Their Effectiveness.'' Annual 
Review of Environment and Resources 34(1): 305-324.
    \100\ Brouhle, K., C. Griffiths, and A. Wolverton. (2009). 
``Evaluating the role of EPA policy levers: An examination of a 
voluntary program and regulatory threat in the metal-finishing 
industry.'' Journal of Environmental Economics and Management. 
57(2): 166-181.
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    The Natural Gas STAR Program started in 1993 and seeks to achieve 
methane emission reductions through cost-effective best practices and 
technologies. Partner companies document their voluntary emission 
reduction activities and report their accomplishments to the EPA 
annually. Natural Gas STAR includes over 100 partners across the 
natural gas value chain and has eliminated nearly 1.39 trillion cubic 
feet of methane emissions since 1993.
    The Methane Challenge Program, started in 2016 and designed for 
companies that want to adopt more ambitious actions for methane 
reductions, expands the Natural Gas STAR Program through specific, 
ambitious commitments; transparent reporting; and company-level 
recognition of commitments and progress. This program includes more 
than 50 companies from all segments of the industry--production, 
gathering and boosting, transmission and storage, and distribution.
    The Environmental Partnership is comprised of various companies of 
different sizes and includes commitments to replace all high-bleed 
pneumatic controllers with low-bleed controllers (i.e., controllers 
with a bleed rate less than 6 standard cubic feet per hour) within 5 
years, require operators to be on-site or nearby when conducting 
liquids unloading and require initial monitoring for fugitive emissions 
at all sites within 5 years, with repairs completed within 60 days of 
fugitive emissions detection.
    The CCAC Oil and Gas Methane Partnership is a technical partnership 
between oil and natural gas companies, the Environmental Defense Fund, 
the EPA Natural Gas STAR Program, and the Global Methane Initiative 
that provides technical documents on a wide variety of opportunities 
for reducing methane emissions and requires annual progress reports 
from its participants. Yearly data on the progress being made by 
participants is available on the CCAC website.\101\
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    \101\ http://ccacoalition.org/en/content/oil-and-gas-methane-partnership-reporting.
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    While the GHGI already accounts for these voluntary reductions, the 
adoption of control technologies and emission reduction practices of 
participating companies reporting to the EPA's programs, the EPA 
understands it takes time for newly launched voluntary efforts to 
demonstrate reductions. The

[[Page 50277]]

EPA also understands that not all sources participate in voluntary 
programs, although participation may increase over time. The EPA 
solicits data and information that the EPA can use to evaluate the 
aggregate present impact and potential future impact of oil and natural 
gas industry participation in voluntary programs.
4. State Regulatory Programs
    Several major oil and natural gas producing states have established 
regulations on oil and natural gas sector emissions. These states 
include California (CA), Colorado (CO), Montana (MT), New Mexico (NM), 
North Dakota (ND), Ohio (OH), Pennsylvania (PA), Texas (TX), Utah (UT), 
and Wyoming (WY).\102\ In 2018 within the U.S., these states 
contributed about 71 percent of crude oil production \103\ and 69 
percent of natural gas production.\104\ A comparison of sources covered 
by state rules, regulated pollutants, and the regulatory status of the 
transmission and storage segment, is presented in Table 9.
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    \102\ This list does not differentiate which states are covering 
existing and/or new sources. We note that states may define existing 
and new sources differently than the EPA.
    \103\ https://www.eia.gov/state/rankings/#/series/46.
    \104\ https://www.eia.gov/state/rankings/#/series/47.

                                              Table 9--Comparison of State Oil and Natural Gas Regulations
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                      CA          CO          MT          ND          NM          OH          PA          TX          UT          WY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                         Source
--------------------------------------------------------------------------------------------------------------------------------------------------------
Storage Vessels................  Yes........  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.
Reciprocating Compressors......  Yes........  Yes.......  No........  No........  No........  Yes.......  Yes.......  No........  No........  No.
Centrifugal Compressors........  Yes........  Yes.......  No........  No........  No........  Yes.......  Yes.......  No........  No........  No.
Pneumatic Controllers..........  Yes........  Yes.......  No........  No........  No........  Yes.......  Yes.......  No........  Yes.......  Yes.
Pneumatic Pumps................  Yes........  Yes.......  No........  No........  No........  Yes.......  Yes.......  No........  No........  Yes.
Equipment Leaks at Natural Gas   Yes........  Yes.......  No........  No........  No........  No........  Yes.......  Yes.......  No........  No.
 Processing Plants.
Fugitive Emissions at Well       Yes........  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.......  Yes.
 Sites.
Fugitive Emissions at            Yes........  Yes.......  No........  No........  No........  Yes.......  Yes.......  No........  No........  Yes.
 Compressor Stations.
Methane Standards..............  Yes........  Yes.......  No........  No........  No........  No........  Yes.......  No........  No........  No.
Transmission and Storage         Yes........  Yes.......  No........  No........  No........  Yes.......  Yes.......  No........  No........  Yes.
 Segment.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    While not all of these states cover all emission sources covered by 
the NSPS OOOO and OOOOa, all have requirements for storage vessels and 
fugitive emissions at well sites, two of the largest emission sources 
within the oil and natural gas industry. Select aspects of the fugitive 
emissions programs for these states were evaluated as potential 
alternative standards to changes to 2016 NSPS OOOOa that the EPA 
proposed by notice dated October 15, 2018, 83 FR 52056. The states with 
programs proposed to be included as alternative fugitive standards 
include CA, CO, OH, and PA for both well sites and compressor stations, 
and TX and UT for well sites only.\105\ Alaska, Oklahoma, and West 
Virginia incorporate NSPS OOOO and OOOOa by reference into state rules.
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    \105\ https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry/proposed-improvements-2016-new-source.
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    Three states, including CA, CO, and PA, regulate methane emissions 
explicitly.\106\ California requires emissions from storage vessels 
emitting more than 10 tpy of methane to be routed to a vapor control 
system. In addition, CA does not allow for pneumatic pumps to vent 
methane emissions to the atmosphere. Colorado requires certain HC 
destruction efficiencies for storage vessels, as well as general 
requirements to design operations so that HC emissions are minimized. 
Pennsylvania's General Permits 5 and 5A require various emission 
sources emitting over 200 tpy of methane to control their emissions by 
95 percent. These emission sources include dehydrators, storage 
vessels, pigging operations, and tanker truck load-out operations. In 
addition, the definition of ``fugitive emission component'' within 
these permits explicitly includes those components that have the 
potential to emit methane. The permits require quarterly instrument 
monitoring for compressor stations and unconventional well sites. While 
other states only regulate VOC, measures that reduce VOC will also 
reduce methane. The EPA solicits comment describing what other states 
are doing to reduce methane emissions from the oil and natural gas 
industry, and, more broadly, whether there are enough consistent state 
requirements in place that will meaningfully reduce emissions should 
the primary proposal be finalized. Additionally, the EPA does not 
current have the capability to produce state-level projections of 
sources in transmission and storage that are potentially affected by 
this action. Because of this, we are unable to perform any quantitative 
analysis of state programs with similar requirements. As a result, the 
EPA also solicits information that will help the Agency project 
potentially-affected facilities in the transmission and storage segment 
at the state level.
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    \106\ Colorado includes requirements on methane emissions in the 
form of HC.
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VIII. Impacts of This Proposed Rule

A. What are the air impacts?

    The EPA estimated the change in emissions that will occur due to 
the implementation of the primary and alternative options in this 
proposal for the analysis years of 2019 through 2025. The EPA estimates 
impacts beginning in 2019 to reflect the year implementation of this 
proposal. The EPA estimates impacts through 2025 to illustrate the 
accumulating effect of this rule, if finalized as proposed, over a 
longer period. The EPA does not estimate impacts after 2025 for reasons 
including limited information, as explained in the RIA. The RIA 
estimates for 2025 include sources newly affected in 2025 as well as 
the accumulation of affected sources from 2016 to 2024 that are also 
assumed to be in continued operation in 2025, thus, incurring 
compliance costs and emission reductions in 2025.
    The RIA presents results relative to two alternative baselines for 
this action. The first baseline includes the March 12, 2018 Amendments 
final package and the October 15, 2018 proposed revisions and is 
referred to as the ``2018 Proposed Regulatory'' baseline. The second 
baseline includes the March 12, 2018 Amendments final package but 
excludes the potential impacts of the October 15, 2018 proposed 
revisions and is referred to as the ``Current Regulatory'' baseline.

[[Page 50278]]

A more detailed description of the alternative baselines is presented 
in Section 1.2 of the RIA.
    The EPA estimated that over the 2019 to 2025 time frame, relative 
to the 2018 Proposed Regulatory baseline, the primary proposal would 
increase methane emissions by about 350,000 short tons, VOC emissions 
by about 9,700 tons, and 290 tons of HAP from facilities affected by 
this review. Under the Current Regulatory baseline, the EPA estimated 
that over the 2019 to 2025 time frame, the primary proposal would 
increase methane emissions by about 370,000 short tons VOC emissions by 
about 10,000 tons, and 300 tons of HAP from facilities affected by this 
review.
    Under the alternative proposal, because the methane control options 
are redundant with VOC control options, there are no expected emission 
impacts from rescinding the methane requirement, relative to either of 
the 2018 Proposed Regulatory or the Current Regulatory baselines.
    The EPA solicits comment on the assumptions used in the memorandum 
titled ``Draft Control Cost and Emission Changes under the Proposed 
Amendments to 40 CFR part 60, subpart OOOOa Under Executive Order 
13783.

B. What are the energy impacts?

    Energy impacts in this section are those energy requirements 
associated with the operation of emissions control devices. Potential 
impacts on the national energy economy from the rule are discussed in 
the economic impacts section. Under the primary proposal, there would 
be little change in the national energy demand from the operation of 
any of the environmental controls proposed in this action. The 
alternative proposal would lead to no changes in compliance activities 
and, as a result, would not produce any energy impacts. This conclusion 
is independent of the choice of baseline used in the analysis 
supporting this action.

C. What are the compliance costs?

    Under the 2018 Proposed Regulatory baseline, the EPA estimates the 
present value (PV) of compliance cost savings of the primary proposal 
over 2019-2025, discounted back to 2016, will be $104 million (in 2016 
dollars) using a 7 percent discount rate and $133 million using a 3 
percent discount rate, not including the forgone producer revenues 
associated with the decrease in the recovery of saleable natural gas. 
The equivalent annualized value (EAV) of these cost savings are $18 
million per year using a 7 percent discount rate and $21 million per 
year using a 3 percent discount rate. In this analysis, the EPA uses 
the 2018 Annual Energy Outlook (AEO) projection of natural gas prices 
to estimate the value of the change in the recovered gas at the 
wellhead. After accounting for the change in these revenues, the 
estimate of the PV of compliance cost savings of the proposed review 
over 2019-2025, discounted back to 2016, are estimated to be $81 
million using a 7 percent discount rate, and $103 million using a 3 
percent discount rate; the corresponding estimates of the EAV of cost 
savings after accounting for the forgone revenues are $14 million per 
year using a 7 percent discount rate, and $16 million per year using a 
3 percent discount rate.
    Under the Current Regulatory baseline, the EPA estimates the 
present value (PV) of compliance cost savings of the primary proposal 
over 2019-2025, discounted back to 2016, will be $122 million (in 2016 
dollars) using a 7 percent discount rate and $155 million using a 3 
percent discount rate, not including the forgone producer revenues 
associated with the decrease in the recovery of saleable natural gas. 
The equivalent annualized value (EAV) of these cost savings are $21 
million per year using a 7 percent discount rate and $24 million per 
year using a 3 percent discount rate. After accounting for the change 
in these revenues, the estimate of the PV of compliance cost savings of 
the proposed review over 2019-2025, discounted back to 2016, are 
estimated to be $97 million using a 7 percent discount rate, and $123 
million using a 3 percent discount rate; the corresponding estimates of 
the EAV of cost savings after accounting for the forgone revenues are 
$17 million per year using a 7 percent discount rate, and $19 million 
per year using a 3 percent discount rate.
    Under the alternative proposal, because the methane control options 
are redundant with VOC control options, there are no expected changes 
in the cost or emissions from rescinding the methane requirements 
relative to either baseline used in the analysis supporting this 
action.
    Under the alternative proposal, because the methane control options 
are redundant with VOC control options, there are no expected changes 
in the cost or emissions from rescinding the methane requirements 
relative to either baseline used in the analysis supporting this 
action.

D. What are the economic and employment impacts?

    The EPA used the National Energy Modeling System (NEMS) to estimate 
the impacts of the 2016 NSPS OOOOa on the U.S. energy system. The NEMS 
is a publicly-available model of the U.S. energy economy developed and 
maintained by the U.S. EIA and is used to produce the AEO, a reference 
publication that provides detailed projections of the U.S. energy 
economy.
    The EPA estimated small impacts on crude oil and natural gas 
markets of the 2016 NSPS OOOOa rule over the 2020 to 2025 period. If 
finalized, the primary proposal would result in a decrease in total 
compliance costs. Therefore, the EPA expects that the primary proposal 
would partially reduce the impacts estimated for the 2016 NSPS OOOOa in 
the 2016 NSPS OOOOa RIA. The alternative proposal, if finalized, would 
lead to no cost impacts and no changes in the estimated impacts of the 
2016 NSPS OOOOa rule. This conclusion is independent of the choice of 
baseline used in the analysis supporting this action.
    Executive Order 13563 directs federal agencies to consider the 
effect of regulations on job creation and employment. According to the 
Executive Order, ``our regulatory system must protect public health, 
welfare, safety, and our environment while promoting economic growth, 
innovation, competitiveness, and job creation. It must be based on the 
best available science.'' (Executive Order 13563, 2011). While a 
standalone analysis of employment impacts is not included in a standard 
benefit-cost analysis, such an analysis is of concern in the current 
economic climate given continued interest in the employment impact of 
regulations such as this proposed rule.
    The EPA estimated the labor impacts due to the installation, 
operation, and maintenance of control equipment, control activities, 
and labor associated with new reporting and recordkeeping requirements 
in the 2016 NSPS OOOOa RIA. Under the primary proposal, the EPA expects 
there will be slight reductions in the labor required for compliance-
related activities associated with the 2016 NSPS OOOOa requirements 
relating to the rescission of requirements in the transmission and 
storage segment of the oil and natural gas industry. Under the 
alternative proposal, the EPA expects no changes in labor-related 
compliance requirements associated with the 2016 NSPS OOOOa rule. These 
conclusions are independent

[[Page 50279]]

of the choice of baseline used in the analysis supporting this action.

E. What are the benefits of the proposed standards?

    The EPA expects forgone climate and health benefits due to the 
increase in emissions resulting from the primary proposal which would 
remove requirements in the transmission and storage segment. Under the 
alternative proposal, because the methane control options are redundant 
with VOC control options, there are no expected emissions impacts from 
rescinding the methane requirement; hence, there would be no forgone 
climate and health benefits resulting from the alternative option. 
These conclusions are independent of the choice of baseline used in the 
analysis supporting this action.
    The EPA estimated the forgone domestic climate benefits from the 
increase in methane emissions associated with the action using an 
interim measure of the domestic social cost of methane (SC-
CH4). The SC-CH4 estimates used here were 
developed under Executive Order 13783 for use in regulatory analyses 
until an improved estimate of the impacts of climate change to the U.S. 
can be developed based on the best available science and economics. 
Executive Order 13783 directed agencies to ensure that estimates of the 
social cost of GHG used in regulatory analyses ``are based on the best 
available science and economics'' and are consistent with the guidance 
contained in OMB Circular A-4, ``including with respect to the 
consideration of domestic versus international impacts and the 
consideration of appropriate discount rates'' (Executive Order 13783, 
Section 5(c)). In addition, Executive Order 13783 withdrew the 
technical support documents (TSDs) and the August 2016 Addendum to 
these TSDs describing the global social cost of GHG estimates developed 
under the prior Administration as no longer representative of 
government policy. The withdrawn TSDs and Addendum were developed by an 
interagency working group that included the EPA and other executive 
branch entities and were used in the 2016 NSPS OOOOa RIA.
    Under the primary proposal, the EPA expects that the forgone VOC 
emission reductions will degrade air quality and are likely to 
adversely affect health and welfare associated with exposure to ozone, 
PM2.5, and HAP, but we are unable to quantify these effects 
at this time. This omission should not imply that these forgone 
benefits do not exist, and to the extent that EPA were to quantify 
these ozone and PM impacts, it would estimate the number and value of 
avoided premature deaths and illnesses using an approach detailed in 
the Particulate Matter NAAQS and Ozone NAAQS Regulatory Impact Analyses 
(U.S. EPA, 2012; U.S. EPA, 2015).
    When quantifying the incidence and economic value of the human 
health impacts of air quality changes, the Agency often relies upon 
reduced-form techniques; these are often reported as ``benefit-per-
ton'' values that relate air pollution impacts to changes in air 
pollutant precursor emissions (U.S. EPA, 2018). A small but growing 
literature characterizes the air quality and health impacts from the 
oil and natural gas industry, but does not yet supply the information 
needed to derive a VOC benefit per ton value suitable for a regulatory 
analysis (Fann, et al., 2018; Litovitz, et al., 2013; Loomis, et al., 
2017).\107\ Moreover, the Agency is currently comparing various 
reduced-form techniques, including benefit per ton approaches that 
quantify air quality benefits. Over the last year and a half, the EPA 
systematically compared the changes in benefits, and concentrations 
where available, from its benefit-per-ton technique and other reduced-
form techniques to the changes in benefits and concentration derived 
from full-form photochemical model representation of a few different 
specific emissions scenarios.\108\ The Agency's goal was to better 
understand the suitability of alternative reduced-form air quality 
modeling techniques for estimating the health impacts of criteria 
pollutant emissions changes in the EPA's benefit-cost analysis, 
including the extent to which reduced form models may over- or under-
estimate benefits (compared to full-scale modeling) under different 
scenarios and air quality concentrations. The scenario-specific 
emission inputs developed for this project are currently available 
online.\109\ The study design and methodology will be thoroughly 
described in the final report summarizing the results of the project, 
which is planned to be completed by the end of 2019.
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    \107\ Fann, N., et al. (2018). ``Assessing Human Health 
PM2.5 and Ozone Impacts from U.S. Oil and Natural Gas 
Sector Emissions in 2025.'' Environmental Science & Technology 
52(15): 8095-8103.
    Litovitz, A., et al. (2013). ``Estimation of regional air-
quality damages from Marcellus Shale natural gas extraction in 
Pennsylvania.'' Environmental Research Letters 8(1): 014017.
    Loomis, J. and M. Haefele (2017). ``Quantifying Market and Non-
market Benefits and Costs of Hydraulic Fracturing in the United 
States: A Summary of the Literature.'' Ecological Economics 138: 
160-167.
    \108\ This analysis compared the benefits estimated using full-
form photochemical air quality modeling simulations (CMAQ and CAMx) 
against four reduced-form tools, including: InMAP; AP2/3; EASIUR and 
the EPA's benefit-per-ton.
    \109\ The scenario-specific emission inputs developed for this 
project are currently available online at: https://github.com/epa-kpc/RFMEVAL. Upon completion and publication of the final report, 
the final report and all associated documentation will be online and 
available at this URL.
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    Relative to the 2018 Proposed Regulatory baseline, the PV of the 
estimated forgone domestic climate benefits over 2019-2025, discounted 
back to 2016, is $13 million using a 7 percent discount rate and $49 
million using a 3 percent discount rate. The EAV of these estimated 
forgone climate benefits is $2.2 million per year using 7 percent 
discount rate and $7.7 million per year using a 3 percent discount 
rate. Under the Current Regulatory baseline, the PV of the estimated 
forgone domestic climate benefits over 2019-2025, discounted back to 
2016, will be $13 million using a 7 percent discount rate and $52 
million using a 3 percent discount rate. The EAV of these estimated 
forgone climate benefits is $2.3 million per year using 7 percent 
discount rate and $8.1 million per year using a 3 percent discount 
rate. These values represent only a partial accounting of domestic 
climate impacts from methane emissions and do not account for health 
effects of ozone exposure from the increase in methane emissions.

IX. 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 a significant regulatory action that was submitted 
to OMB for review because it raises novel legal or policy issues. Any 
changes made in response to OMB recommendations have been documented in 
the docket. In addition, the EPA prepared an RIA of the potential costs 
associated with the primary and alternative proposals in this action. 
The RIA available in the docket describes in detail the empirical basis 
for the EPA's assumptions and characterizes the various sources of 
uncertainties affecting the estimates below.

[[Page 50280]]

    The RIA presents results relative to two alternative baselines for 
this action. The first baseline includes the March 12, 2018 Amendments 
final package and the October 15, 2018 proposed revisions and is 
referred to as the ``2018 Proposed Regulatory'' baseline. The second 
baseline includes the March 2018 Amendments final package but excludes 
the potential impacts of the October 15, 2018 proposed revisions and is 
referred to as the ``Current Regulatory'' baseline. A more detailed 
description of the alternative baselines is presented in Section 1.2.2 
of the RIA.
    Table 10 shows the present value and equivalent annualized value 
results of the cost and benefits analysis for the primary proposal for 
2019 through 2025 relative to the 2018 Proposed Regulatory baseline 
discounted back to 2016 using a discount rate of 7 percent. The table 
also shows the total increase in emissions from 2019 through 2025 from 
the primary proposal relative to the 2018 Proposed Regulatory baseline. 
When discussing net benefits, we modify the relevant terminology to be 
more consistent with traditional net benefits analysis. In the 
following table, we refer to the cost savings as presented in section 2 
of the RIA, and in section VII.C above, as the ``benefits'' of this 
proposed action and the forgone benefits as presented in section 3 of 
the RIA, and in section VIII.E above, as the ``costs'' of this proposed 
action. Total cost savings are cost savings less the forgone value of 
product recovery. The net benefits are the benefits (total cost 
savings) minus the costs (forgone domestic climate benefits).
    Table 10 shows the present value and equivalent annualized value 
results of the cost and benefits analysis for the primary proposal for 
2019 through 2025 relative to the 2018 Proposed Regulatory baseline 
discounted back to 2016 using a discount rate of 7 percent. The table 
also shows the total increase in emissions from 2019 through 2025 from 
the primary proposal relative to the 2018 Proposed Regulatory baseline. 
When discussing net benefits, we modify the relevant terminology to be 
more consistent with traditional net benefits analysis. In the 
following table, we refer to the cost savings as presented in Section 2 
of the RIA, and in section VII.C above, as the ``benefits'' of this 
proposed action and the forgone benefits as presented in Section 3 of 
the RIA, and in section VIII.E above, as the ``costs'' of this proposed 
action. Total cost savings are cost savings less the forgone value of 
product recovery. The net benefits are the benefits (total cost 
savings) minus the costs (forgone domestic climate benefits).

 Table 10--Summary of the Present Value and Equivalent Annualized Value of the Monetized Forgone Benefits, Cost
     Savings, and Net Benefits of the Primary Proposal From 2019 Through 2025 Relative to the 2018 Proposed
                                               Regulatory Baseline
                                               [Millions of 2016$]
----------------------------------------------------------------------------------------------------------------
                                                                                                   Equivalent
                                                                              Present value     annualized value
----------------------------------------------------------------------------------------------------------------
Benefits (Total Cost Savings).............................................                $81                $14
    Cost Savings..........................................................                104                 18
    Forgone Value of Product Recovery.....................................                 23                4.0
Costs (Forgone Domestic Climate Benefits).................................                 13                2.2
Net Benefits..............................................................                 69                 12
                                                                           -------------------------------------
Non-monetized Forgone Benefits............................................  Non-monetized climate impacts from
                                                                            increases in methane emissions.
                                                                            Health effects of PM2.5 and ozone
                                                                            exposure from an increase of 9,700
                                                                            tons of VOC from 2019 through 2025.
                                                                            Health effects of HAP exposure from
                                                                            an increase of 290 tons of HAP from
                                                                            2019 through 2025.
                                                                            Health effects of ozone exposure
                                                                            from an increase of 350,000 short
                                                                            tons of methane from 2019 through
                                                                            2025.
                                                                            Visibility impairment.
                                                                            Vegetation effects.
----------------------------------------------------------------------------------------------------------------
Estimates may not sum due to independent rounding.

    Table 11 shows the present value and equivalent annualized value 
results of the cost and benefits analysis for the primary proposal for 
2019 through 2025 relative to the Current Regulatory baseline, 
discounted back to 2016 using a discount rate of 7 percent. The table 
also shows the total increase in emissions from 2019 through 2025 from 
the primary proposal relative to the Current Regulatory baseline.

 Table 11--Summary of the Present Value and Equivalent Annualized Value of the Monetized Forgone Benefits, Cost
   Savings, and Net Benefits of the Primary Proposal From 2019 Through 2025 Relative to the Current Regulatory
                                                    Baseline
                                               [Millions of 2016$]
----------------------------------------------------------------------------------------------------------------
                                                                                                   Equivalent
                                                                              Present value     annualized value
----------------------------------------------------------------------------------------------------------------
Benefits (Total Cost Savings).............................................                $97                $17
    Cost Savings..........................................................                122                 21
    Forgone Value of Product Recovery.....................................                 25                4.4

[[Page 50281]]

 
Costs (Forgone Domestic Climate Benefits).................................                 13                2.3
Net Benefits..............................................................                 83                 14
                                                                           -------------------------------------
Non-monetized Forgone Benefits............................................  Non-monetized climate impacts from
                                                                            increases in methane emissions.
                                                                            Health effects of PM2.5 and ozone
                                                                            exposure from an increase of 10,000
                                                                            tons of VOC from 2019 through 2025.
                                                                            Health effects of HAP exposure from
                                                                            an increase of 300 tons of HAP from
                                                                            2019 through 2025.
                                                                            Health effects of ozone exposure
                                                                            from an increase of 370,000 short
                                                                            tons of methane from 2019 through
                                                                            2025.
                                                                            Visibility impairment.
                                                                            Vegetation effects.
----------------------------------------------------------------------------------------------------------------
Estimates may not sum due to independent rounding.

    Under the alternative proposal, because the methane control options 
are redundant with VOC control options, there are no expected cost or 
emissions impacts from rescinding the methane requirement. As a result, 
Table 12 depicts this ``no-change'' in impacts result relative to the 
2018 Proposed Regulatory baseline. The no-change in impacts result also 
applies relative to the Current Regulatory baseline, as shown in Table 
13.

 Table 12--Summary of the Present Value and Equivalent Annualized Value of the Monetized Forgone Benefits, Cost
   Savings, and Net Benefits of the Alternative Proposal From 2019 Through 2025 Relative to the 2018 Proposed
                                               Regulatory Baseline
                                               [Millions of 2016$]
----------------------------------------------------------------------------------------------------------------
                                                                                                   Equivalent
                                                                              Present value     annualized value
----------------------------------------------------------------------------------------------------------------
Benefits (Total Cost Savings).............................................                 $0                 $0
Costs (Forgone Domestic Climate Benefits).................................                  0                  0
Net Benefits..............................................................                  0                  0
                                                                           -------------------------------------
Non-monetized Forgone Benefits............................................                No change
----------------------------------------------------------------------------------------------------------------
Estimates may not sum due to independent rounding.


 Table 13--Summary of the Present Value and Equivalent Annualized Value of the Monetized Forgone Benefits, Cost
 Savings, and Net Benefits of the Alternative Proposal From 2019 Through 2025 Relative to the Current Regulatory
                                                    Baseline
                                               [Millions of 2016$]
----------------------------------------------------------------------------------------------------------------
                                                                                                   Equivalent
                                                                              Present value     annualized value
----------------------------------------------------------------------------------------------------------------
Benefits (Total Cost Savings).............................................                 $0                 $0
Costs (Forgone Domestic Climate Benefits).................................                  0                  0
Net Benefits..............................................................                  0                  0
                                                                           -------------------------------------
Non-monetized Forgone Benefits............................................                No change
----------------------------------------------------------------------------------------------------------------
Estimates may not sum due to independent rounding.

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

    This action is expected to be an Executive Order 13771 deregulatory 
action. Details on the estimated cost savings of this proposed rule can 
be found in the EPA's analysis of the potential costs and benefits 
associated with this action.

C. Paperwork Reduction Act (PRA)

    The information collection requirements in this rule have been 
submitted for approval to the Office of Management and Budget (OMB) 
under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The 
Information Collection Request (ICR) document prepared by the EPA has 
been assigned the EPA ICR number 2604.01 and OMB Control

[[Page 50282]]

Number 2060-NEW. The information collection requirements are not 
enforceable until OMB approves them.
    A summary of the information collection activities previously 
submitted to the OMB for the final action titled ``Standards of 
Performance for Crude Oil and Natural Gas Facilities for Construction, 
Modification, or Reconstruction'' (2016 NSPS OOOOa) under the PRA, and 
assigned OMB Control Number 2060-0721, can be found at 81 FR 35890. You 
can find a copy of the information collection request (ICR) in the 2016 
NSPS OOOOa docket (EPA-HQ-OAR-2010-0505-7626). The EPA subsequently 
proposed reconsideration (October 15, 2018, 83 FR 52056.) to revise the 
information collection activities of 2016 NSPS OOOOa (EPA ICR number 
2523.02). You can find a copy of the revised ICR (EPA ICR number 
2523.02) in the 2018 NSPS OOOOa docket (EPA-HQ-OAR-2017-0483). In this 
rule, the EPA is proposing to further revise the October 15, 2018, NSPS 
OOOOa reconsideration proposal ICR based on those proposed amendments 
as a result of the EPA's review under Executive Order 13783 (EPA ICR 
number 2523.04). These proposed changes (2019 NSPS OOOOa E.O. 13783 
Review Proposal) would reduce the burden on the regulated industry 
associated with reporting and recordkeeping requirements of the 
rescinded requirements.
    Burden associated with this rule (2019 NSPS OOOOa E.O. 13783 Review 
Proposal):
    Respondents/affected entities: Oil and natural gas operators and 
owners.
    Respondent's obligation to respond: Mandatory.
    Estimated number of respondents: 3,648.
    Frequency of response: Varies depending on affected facility.\110\
---------------------------------------------------------------------------

    \110\ The specific frequency for each information collection 
activity within this request is shown in Tables 1a-1d of the 
Supporting Statement in the public docket.
---------------------------------------------------------------------------

    Total estimated annual burden: 230,285 hours. Burden is defined at 
5 CFR 1320.3(b).
    Total estimated annual cost: $14,177,438 (2016$) includes $0 in 
annualized capital or operation & maintenance costs.
    This represents a burden reduction of 2 percent compared to the 
burden estimated for the 2016 NSPS OOOOa. This represents a burden 
reduction of 16 percent compared to the 2018 NSPS OOOOa Reconsideration 
Proposal amendments. Submit your comments on the Agency's need for this 
information, the accuracy of the provided revised 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_submissions@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 October 24, 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. An Agency may certify that a 
rule will not have a significant economic impact on a substantial 
number of small entities if the rule relieves regulatory burden, has no 
net burden, or otherwise has a positive economic effect on the small 
entities subject to the rule. This is a deregulatory action, and the 
burden on all entities affected by this proposed rule, including small 
entities, is the same or reduced compared to the 2016 NSPS OOOOa. See 
the discussion in section VIII of this preamble and the RIA for 
details. The EPA has, therefore, concluded that this action will not 
increase regulatory burden for all directly regulated 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.

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

    This action does not have tribal implications, as specified in 
Executive Order 13175. It will not have substantial direct effects on 
tribal governments, on the relationship between the federal government 
and Indian tribes, or on the distribution of power and responsibilities 
between the federal government and Indian tribes, as specified in 
Executive Order 13175. 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. The 
2016 NSPS OOOOa, as discussed in the RIA,\111\ was anticipated to 
reduce emissions of methane, VOC, and HAP, and some of the benefits of 
reducing these pollutants would have accrued to children. The primary 
proposal is expected to decrease the impact of the emissions reductions 
estimated from the 2016 NSPS OOOOa on these benefits, as discussed in 
Chapter 1 of the RIA. Under the alternative proposal, because the 
methane control options are redundant with VOC control options, there 
are no changes in the level of environmental protection produced by the 
2016 NSPS OOOOa emissions impacts from rescinding the methane 
requirement.
    The proposed action does not affect the level of public health and 
environmental protection already being provided by existing NAAQS and 
other mechanisms in the CAA. This proposed action does not affect 
applicable local, state, or federal permitting or air quality 
management programs that will continue to address areas with degraded 
air quality and maintain the air quality in areas meeting current 
standards. Areas that need to reduce criteria air pollution to meet the 
NAAQS will still need to rely on control strategies to reduce 
emissions. The EPA does not believe the decrease in emission reductions 
projected under the primary proposal of this action will have a 
disproportionate adverse effect on children's health.

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution, or use of energy. The basis for this determination can be 
found in the 2016 NSPS OOOOa (81 FR 35894).

[[Page 50283]]

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 proposed action is unlikely to 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 2016 NSPS OOOOa was anticipated to reduce 
emissions of methane, VOC, and HAP, and some of the benefits of 
reducing these pollutants would have accrued to minority populations, 
low-income populations, and/or indigenous peoples. The primary proposal 
is expected to decrease the impact of the emission reductions estimated 
from the 2016 NSPS OOOOa on these benefits. These communities may 
experience forgone benefits as a result of this action, as discussed in 
Chapter 1 of the RIA. Under the alternative proposal, because the 
methane control options are redundant with VOC control options, there 
are no changes in the level of environmental protection produced by the 
2016 NSPS OOOOa emissions impacts from rescinding the methane 
requirement.
    The proposed action does not affect the level of public health and 
environmental protection already being provided by existing NAAQS and 
other mechanisms in the CAA. This proposed action does not affect 
applicable local, state, or federal permitting or air quality 
management programs that will continue to address areas with degraded 
air quality and maintain the air quality in areas meeting current 
standards. Areas that need to reduce criteria air pollution to meet the 
NAAQS will still need to rely on control strategies to reduce 
emissions.
    The EPA believes that this proposed action is unlikely to have 
disproportionately high and adverse human health or environmental 
effects on minority populations, low-income populations, and/or 
indigenous peoples. The EPA notes that the potential impacts of the 
primary proposal are not expected to be experienced uniformly, and the 
distribution of avoided compliance costs associated with this action 
depends on the degree to which costs would have been passed through to 
consumers.

List of Subjects in 40 CFR Part 60

    Environmental protection, Administrative practice and procedure, 
Air pollution control, Reporting and recordkeeping requirements.

    Dated: August 28, 2019.
Andrew R. Wheeler,
Administrator.

    For the reasons set out in the preamble, EPA proposes to amend 40 
CFR part 60 as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

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

Subpart OOOO--Standards of Performance for Crude Oil and Natural 
Gas Facilities for Which Construction, Modification or 
Reconstruction Commenced After August 23, 2011, and on or Before 
September 18, 2015

0
2. Revise the heading of subpart OOOO to read as set forth above.
0
3. Section 60.5365 is amended by revising paragraph (e) to read as 
follows:


Sec.  60.5365  Am I subject to this subpart?

* * * * *
    (e) Each storage vessel affected facility, which is a single 
storage vessel located between the wellhead and the point of custody 
transfer to the natural gas transmission and storage segment, and has 
the potential for VOC emissions equal to or greater than 6 tpy as 
determined according to this section by October 15, 2013 for Group 1 
storage vessels and by April 15, 2014, or 30 days after startup 
(whichever is later) for Group 2 storage vessels, except as provided in 
paragraphs (e)(1) through (4) of this section. The potential for VOC 
emissions must be calculated using a generally accepted model or 
calculation methodology, based on the maximum average daily throughput 
determined for a 30-day period of production prior to the applicable 
emission determination deadline specified in this section. The 
determination may take into account requirements under a legally and 
practically enforceable limit in an operating permit or other 
requirement established under a Federal, State, local or tribal 
authority.
* * * * *
0
4. Section 60.5420 is amended by revising paragraph (c)(5)(iv) to read 
as follows:


Sec.  60.5420   What are my notification, reporting, and recordkeeping 
requirements?

* * * * *
    (c) * * *
    (5) * * *
    (iv) For storage vessels that are skid-mounted or permanently 
attached to something that is mobile (such as trucks, railcars, barges 
or ships), records indicating the number of consecutive days that the 
vessel is located a between the wellhead and the point of custody 
transfer to the natural gas transmission and storage segment. If a 
storage vessel is removed from a site and, within 30 days, is either 
returned to or replaced by another storage vessel at the site to serve 
the same or similar function, then the entire period since the original 
storage vessel was first located at the site, including the days when 
the storage vessel was removed, will be added to the count towards the 
number of consecutive days.
* * * * *

Subpart OOOOa--Standards of Performance for Crude Oil and Natural 
Gas Facilities for Which Construction, Modification or 
Reconstruction Commenced After September 18, 2015

0
5. Revise Sec.  60.5360a to read as follows:


Sec.  60.5360a  What is the purpose of this subpart?

    (a) This subpart establishes emission standards and compliance 
schedules for the control of volatile organic compounds (VOC) and 
sulfur dioxide (SO2) emissions from affected facilities in 
the crude oil and natural gas source category that commence 
construction, modification or reconstruction after September 18, 2015. 
The effective date of the rule is August 2, 2016.
    (b) [Reserved]
0
6. Section 60.5365a is amended by revising paragraphs (b) through (d), 
the introductory text of paragraph (e) and paragraph (j) to read as 
follows:


Sec.  60.5365a  Am I subject to this subpart?

* * * * *
    (b) Each centrifugal compressor affected facility, which is a 
single centrifugal compressor using wet seals that is located between 
the wellhead and the point of custody transfer to the natural gas 
transmission and storage segment. A centrifugal compressor located at a 
well site, or an adjacent well site and servicing more than one well 
site, is not an affected facility under this subpart.
    (c) Each reciprocating compressor affected facility, which is a 
single reciprocating compressor that is located

[[Page 50284]]

between the wellhead and the point of custody transfer to the natural 
gas transmission and storage segment. A reciprocating compressor 
located at a well site, or an adjacent well site and servicing more 
than one well site, is not an affected facility under this subpart.
    (d)(1) For the oil production segment (between the wellhead and the 
point of custody transfer to an oil pipeline), each pneumatic 
controller affected facility, which is a single continuous bleed 
natural gas-driven pneumatic controller operating at a natural gas 
bleed rate greater than 6 scfh.
    (2) For the natural gas production segment (between the wellhead 
and the point of custody transfer to the natural gas transmission and 
storage segment and not including natural gas processing plants), each 
pneumatic controller affected facility, which is a single continuous 
bleed natural gas-driven pneumatic controller operating at a natural 
gas bleed rate greater than 6 scfh.
    (3) For natural gas processing plants, each pneumatic controller 
affected facility, which is a single continuous bleed natural gas-
driven pneumatic controller.
    (e) Each storage vessel affected facility, which is a single 
storage vessel that is located between the wellhead and the point of 
custody transfer to the natural gas transmission and storage segment, 
and has the potential for VOC emissions equal to or greater than 6 tpy 
as determined according to this section. The potential for VOC 
emissions must be calculated using a generally accepted model or 
calculation methodology, based on the maximum average daily throughput, 
as defined in Sec.  60.5430a, determined for a 30-day period of 
production prior to the applicable emission determination deadline 
specified in this subsection. The determination may take into account 
requirements under a legally and practically enforceable limit in an 
operating permit or other requirement established under a Federal, 
state, local or tribal authority.
* * * * *
    (j) The collection of fugitive emissions components at a compressor 
station as defined in Sec.  60.5430a, that is located between the 
wellhead and the point of custody transfer to the natural gas 
transmission and storage segment, is an affected facility. For purposes 
of Sec.  60.5397a, a ``modification'' to a compressor station occurs 
when:
    (1) An additional compressor is installed at a compressor station; 
or
    (2) One or more compressors at a compressor station is replaced by 
one or more compressors of greater total horsepower than the 
compressor(s) being replaced. When one or more compressors is replaced 
by one or more compressors of an equal or smaller total horsepower than 
the compressor(s) being replaced, installation of the replacement 
compressor(s) does not trigger a modification of the compressor station 
for purposes of Sec.  60.5397a.
0
7. Section 60.5375a is amended by revising the section heading and the 
introductory text to read as follows:


Sec.  60.5375a  What VOC standards apply to well affected facilities?

    If you are the owner or operator of a well affected facility as 
described in Sec.  60.5365a(a) that also meets the criteria for a well 
affected facility in Sec.  60.5365(a) of subpart OOOO of this part, you 
must reduce VOC emissions by complying with paragraphs (a) through (g) 
of this section. If you own or operate a well affected facility as 
described in Sec.  60.5365a(a) that does not meet the criteria for a 
well affected facility in Sec.  60.5365(a) of subpart OOOO of this 
part, you must reduce VOC emissions by complying with paragraphs 
(f)(3), (f)(4) or (g) of this section for each well completion 
operation with hydraulic fracturing prior to November 30, 2016, and you 
must comply with paragraphs (a) through (g) of this section for each 
well completion operation with hydraulic fracturing on or after 
November 30, 2016.
* * * * *
0
8. Section 60.5380a is amended by revising the section heading, the 
introductory text and paragraph (a)(1) to read as follows:


Sec.  60.5380a  What VOC standards apply to centrifugal compressor 
affected facilities?

    You must comply with the VOC standards in paragraphs (a) through 
(d) of this section for each centrifugal compressor affected facility.
    (a)(1) You must reduce VOC emissions from each centrifugal 
compressor wet seal fluid degassing system by 95.0 percent.
* * * * *
0
9. Section 60.5385a is amended by revising the section heading, the 
introductory text and paragraph (a)(3) to read as follows:


Sec.  60.5385a  What VOC standards apply to reciprocating compressor 
affected facilities?

    You must reduce VOC emissions by complying with the standards in 
paragraphs (a) through (d) of this section for each reciprocating 
compressor affected facility.
    (a) * * *
    (3) Collect the VOC emissions from the rod packing using a rod 
packing emissions collection system that operates under negative 
pressure and route the rod packing emissions to a process through a 
closed vent system that meets the requirements of Sec.  60.5411a(a) and 
(d).
* * * * *
0
10. Section 60.5390a is amended by revising the section heading and the 
introductory text to read as follows:


Sec.  60.5390a  What VOC standards apply to pneumatic controller 
affected facilities?

    For each pneumatic controller affected facility you must comply 
with the VOC standards, based on natural gas as a surrogate for VOC, in 
either paragraph (b)(1) or (c)(1) of this section, as applicable. 
Pneumatic controllers meeting the conditions in paragraph (a) of this 
section are exempt from this requirement.
* * * * *
0
11. Section 60.5393a is amended by revising the section heading and the 
introductory text to read as follows:


Sec.  60.5393a  What VOC standards apply to pneumatic pump affected 
facilities?

    For each pneumatic pump affected facility you must comply with the 
VOC standards, based on natural gas as a surrogate for VOC, in either 
paragraph (a) or (b) of this section, as applicable, on or after 
November 30, 2016.
* * * * *
0
12. Section 60.5397a is amended by revising the section heading and the 
introductory text to read as follows:


Sec.  60.5397a  What fugitive emissions VOC standards apply to the 
affected facility which is the collection of fugitive emissions 
components at a well site and the affected facility which is the 
collection of fugitive emissions components at a compressor station?

    For each affected facility under Sec.  60.5365a(i) and (j), you 
must reduce VOC emissions by complying with the requirements of 
paragraphs (a) through (j) of this section. These requirements are 
independent of the closed vent system and cover requirements in Sec.  
60.5411a.
* * * * *
0
13. Section 60.5398a is amended by revising the section heading, 
paragraph (a) and paragraph (d)(1)(xii) to read as follows:

[[Page 50285]]

Sec.  60.5398a  What are the alternative means of emission limitations 
for VOC from well completions, reciprocating compressors, the 
collection of fugitive emissions components at a well site and the 
collection of fugitive emissions components at a compressor station?

    (a) If, in the Administrator's judgment, an alternative means of 
emission limitation will achieve a reduction in VOC emissions at least 
equivalent to the reduction in VOC emissions achieved under Sec.  
60.5375a, Sec.  60.5385a, and Sec.  60.5397a, the Administrator will 
publish, in the Federal Register, a notice permitting the use of that 
alternative means for the purpose of compliance with Sec.  60.5375a, 
Sec.  60.5385a, and Sec.  60.5397a. The notice may condition permission 
on requirements related to the operation and maintenance of the 
alternative means.
* * * * *
    (d) * * *
    (1) * * *
    (xii) Operation and maintenance procedures and other provisions 
necessary to ensure reduction in VOC emissions at least equivalent to 
the reduction in VOC emissions achieved under Sec.  60.5397a.
* * * * *
0
14. Amend Sec.  60.5399a by revising paragraph (c) to read as follows:


Sec.  60.5399a  What alternative fugitive emissions standards apply to 
the affected facility which is the collection of fugitive emissions 
components at a well site and the affected facility which is the 
collection of fugitive emissions components at a compressor station: 
Equivalency with state, local, and tribal programs?

* * * * *
    (c) After notice and opportunity for public comment, the 
Administrator will determine whether the requested alternative fugitive 
emissions standard will achieve at least equivalent emission 
reduction(s) in VOC emissions as the reduction(s) achieved under the 
applicable requirement(s) for which an alternative is being requested, 
and will publish the determination in the Federal Register.
* * * * *
0
15. Section 60.5400a is amended by revising the section heading and 
paragraph (c) to read as follows:


Sec.  60.5400a  What equipment leak VOC standards apply to affected 
facilities at an onshore natural gas processing plant?

* * * * *
    (c) You may apply to the Administrator for permission to use an 
alternative means of emission limitation that achieves a reduction in 
emissions of VOC at least equivalent to that achieved by the controls 
required in this subpart according to the requirements of Sec.  
60.5402a.
* * * * *
0
16. Section 60.5401a is amended by revising the section heading to read 
as follows:


Sec.  60.5401a  What are the exceptions to the equipment leak VOC 
standards for affected facilities at onshore natural gas processing 
plants?

* * * * *
0
17. Section 60.5402a is amended by revising the section heading, 
paragraph (a), and paragraph (d)(2) introductory text to read as 
follows:


Sec.  60.5402a  What are the alternative means of emission limitations 
for VOC equipment leaks from onshore natural gas processing plants?

    (a) If, in the Administrator's judgment, an alternative means of 
emission limitation will achieve a reduction in VOC emissions at least 
equivalent to the reduction in VOC emissions achieved under any design, 
equipment, work practice or operational standard, the Administrator 
will publish, in the Federal Register, a notice permitting the use of 
that alternative means for the purpose of compliance with that 
standard. The notice may condition permission on requirements related 
to the operation and maintenance of the alternative means.
* * * * *
    (d) * * *
    (2) The application must include operation, maintenance and other 
provisions necessary to assure reduction in VOC emissions at least 
equivalent to the reduction in VOC emissions achieved under the design, 
equipment, work practice or operational standard in paragraph (a) of 
this section by including the information specified in paragraphs 
(d)(1)(i) through (x) of this section.
* * * * *
0
18. Section 60.5410a is amended by revising paragraph (a) introductory 
text, paragraph (b)(1), paragraph (d) introductory text, and paragraph 
(f) to read as follows:


Sec.  60.5410a  How do I demonstrate initial compliance with the 
standards for my well, centrifugal compressor, reciprocating 
compressor, pneumatic controller, pneumatic pump, storage vessel, 
collection of fugitive emissions components at a well site, collection 
of fugitive emissions components at a compressor station, and equipment 
leaks and sweetening unit affected facilities at onshore natural gas 
processing plants?

* * * * *
    (a) To achieve initial compliance with the VOC standards for each 
well completion operation conducted at your well affected facility you 
must comply with paragraphs (a)(1) through (4) of this section.
* * * * *
    (b)(1) To achieve initial compliance with standards for your 
centrifugal compressor affected facility you must reduce VOC emissions 
from each centrifugal compressor wet seal fluid degassing system by 
95.0 percent or greater as required by Sec.  60.5380a(a) and as 
demonstrated by the requirements of Sec.  60.5413a.
* * * * *
    (d) To achieve initial compliance with VOC emission standards for 
your pneumatic controller affected facility you must comply with the 
requirements specified in paragraphs (d)(1) through (6) of this 
section, as applicable.
* * * * *
    (f) For affected facilities at onshore natural gas processing 
plants, initial compliance with the VOC standards is demonstrated if 
you are in compliance with the requirements of Sec.  60.5400a.
* * * * *
0
19. Section 60.5412a is amended by paragraph (a)(1)(i) and paragraph 
(a)(2) to read as follows:


Sec.  60.5412a  What additional requirements must I meet for 
determining initial compliance with control devices used to comply with 
the emission standards for my centrifugal compressor, and storage 
vessel affected facilities?

* * * * *
    (a) * * *
    (1) * * *
    (i) You must reduce the mass content of VOC in the gases vented to 
the device by 95.0 percent by weight or greater as determined in 
accordance with the requirements of Sec.  60.5413a(b), with the 
exceptions noted in Sec.  60.5413a(a).
* * * * *
    (2) Each vapor recovery device (e.g., carbon adsorption system or 
condenser) or other non-destructive control device must be designed and 
operated to reduce the mass content of VOC in the gases vented to the 
device by 95.0 percent by weight or greater as determined in accordance 
with the requirements of Sec.  60.5413a(b). As an alternative to the 
performance testing requirements, you may demonstrate initial 
compliance by conducting a design analysis for vapor recovery devices 
according to the requirements of Sec.  60.5413a(c).
* * * * *

[[Page 50286]]

0
20. Section 60.5413a is amended by revising paragraph (d)(11)(iii) to 
read as follows:


Sec.  60.5413a  What are the performance testing procedures for control 
devices used to demonstrate compliance at my centrifugal compressor and 
storage vessel affected facilities?

* * * * *
    (d) * * *
    (11) * * *
    (iii) A manufacturer must demonstrate a destruction efficiency of 
at least 95 percent for THC, as propane. A control device model that 
demonstrates a destruction efficiency of 95 percent for THC, as 
propane, will meet the control requirement for 95 percent destruction 
of VOC (if applicable) required under this subpart.
* * * * *
0
21. Section 60.5415a is amended by revising paragraph (b)(1) and 
paragraph (f) to read as follows:


Sec.  60.5415a  How do I demonstrate continuous compliance with the 
standards for my well, centrifugal compressor, reciprocating 
compressor, pneumatic controller, pneumatic pump, storage vessel, 
collection of fugitive emissions components at a well site, and 
collection of fugitive emissions components at a compressor station 
affected facilities, and affected facilities at onshore natural gas 
processing plants?

* * * * *
    (b) * * *
    (1) You must reduce VOC emissions from the wet seal fluid degassing 
system by 95.0 percent or greater.
* * * * *
    (f) For affected facilities at onshore natural gas processing 
plants, continuous compliance with VOC requirements is demonstrated if 
you are in compliance with the requirements of Sec.  60.5400a.
* * * * *
0
22. Section 60.5420a is amended by revising paragraph (c)(5)(iv) to 
read as follows:


Sec.  60.5420a  What are my notification, reporting, and recordkeeping 
requirements?

* * * * *
    (c) * * *
    (5) * * *
    (iv) For storage vessels that are skid-mounted or permanently 
attached to something that is mobile (such as trucks, railcars, barges 
or ships), records indicating the number of consecutive days that the 
vessel is located at a site in the oil and natural gas production 
segment or natural gas processing segment. If a storage vessel is 
removed from a site and, within 30 days, is either returned to the site 
or replaced by another storage vessel at the site to serve the same or 
similar function, then the entire period since the original storage 
vessel was first located at the site, including the days when the 
storage vessel was removed, will be added to the count towards the 
number of consecutive days.
* * * * *
0
23. Section 60.5421a is amended by revising the section heading to read 
as follows:


Sec.  60.5421a  What are my additional recordkeeping requirements for 
my affected facility subject to VOC requirements for onshore natural 
gas processing plants?

* * * * *
0
24. Section 60.5422a is amended by revising the section heading to read 
as follows:


Sec.  60.5422a  What are my additional reporting requirements for my 
affected facility subject to VOC requirements for onshore natural gas 
processing plants?

* * * * *
0
25. Section 60.5430a is amended by:
0
a. Revising the definitions for Compressor station, Crude oil and 
natural gas source category, Equipment, and Fugitive emissions 
component; and
0
b. Adding the definition for First attempt at repair.
    The revisions and addition read as follows:
* * * * *
    Compressor station means any permanent combination of one or more 
compressors that move natural gas at increased pressure through 
gathering pipelines. This includes, but is not limited to, gathering 
and boosting stations. The combination of one or more compressors 
located at a well site, or located at an onshore natural gas processing 
plant, is not a compressor station for purposes of Sec.  60.5397a.
* * * * *
    Crude oil and natural gas source category mean:
    (1) Crude oil production, which includes the well and extends to 
the point of custody transfer to the crude oil transmission pipeline or 
any other forms of transportation; and
    (2) Natural gas production and processing, which includes the well 
and extends to, but does not include, the point of custody transfer to 
the natural gas transmission and storage segment.
* * * * *
    Equipment, as used in the standards and requirements in this 
subpart relative to the equipment leaks of VOC from onshore natural gas 
processing plants, means each pump, pressure relief device, open-ended 
valve or line, valve, and flange or other connector that is in VOC 
service or in wet gas service, and any device or system required by 
those same standards and requirements in this subpart.
* * * * *
    First attempt at repair means, for the purposes of fugitive 
emissions components, an action taken for the purpose of stopping or 
reducing fugitive emissions of VOC to the atmosphere. First attempts at 
repair include, but are not limited to, the following practices where 
practicable and appropriate: Tightening bonnet bolts; replacing bonnet 
bolts; tightening packing gland nuts; or injecting lubricant into 
lubricated packing.
* * * * *
    Fugitive emissions component means any component that has the 
potential to emit fugitive emissions of VOC at a well site or 
compressor station, including valves, connectors, pressure relief 
devices, open-ended lines, flanges, covers and closed vent systems not 
subject to Sec. Sec.  60.5411 or 60.5411a, thief hatches or other 
openings on a controlled storage vessel not subject to Sec. Sec.  
60.5395 or 60.5395a, compressors, instruments, and meters. Devices that 
vent as part of normal operations, such as natural gas-driven pneumatic 
controllers or natural gas-driven pumps, are not fugitive emissions 
components, insofar as the natural gas discharged from the device's 
vent is not considered a fugitive emission. Emissions originating from 
other than the device's vent, such as the thief hatch on a controlled 
storage vessel, would be considered fugitive emissions.
* * * * *
[FR Doc. 2019-19876 Filed 9-23-19; 8:45 am]
 BILLING CODE 6560-50-P


