[Federal Register Volume 84, Number 185 (Tuesday, September 24, 2019)]
[Proposed Rules]
[Pages 50244-50286]
[FR Doc No: 2019-19876]

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

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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<EMAIL_ADDRESS>Include Docket ID No. EPA-
HQ-OAR-2017-0757 in the subject line of the message.
     Fax:<PHONE_NUMBER>. 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:<PHONE_NUMBER>; fax number:<PHONE_NUMBER>;
and email address<EMAIL_ADDRESS>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<EMAIL_ADDRESS>
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<PHONE_NUMBER>, and the telephone number for the EPA
Docket Center is<PHONE_NUMBER>.
    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

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

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

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,

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

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

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

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

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

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

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.
---------------------------------------------------------------------------

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\
---------------------------------------------------------------------------

    \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.

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

    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\
---------------------------------------------------------------------------

    \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

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

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

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.
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    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.
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    \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

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.
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    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.
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    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.

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