[Federal Register Volume 86, Number 217 (Monday, November 15, 2021)]
[Proposed Rules]
[Pages 63110-63263]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-24202]



[[Page 63109]]

Vol. 86

Monday,

No. 217

November 15, 2021

Part II





 Environmental Protection Agency





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40 CFR Part 60





Standards of Performance for New, Reconstructed, and Modified Sources 
and Emissions Guidelines for Existing Sources: Oil and Natural Gas 
Sector Climate Review; Proposed Rule

Federal Register / Vol. 86 , No. 217 / Monday, November 15, 2021 / 
Proposed Rules

[[Page 63110]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60

[EPA-HQ-OAR-2021-0317; FRL-8510-02-OAR]
RIN 2060-AV16


Standards of Performance for New, Reconstructed, and Modified 
Sources and Emissions Guidelines for Existing Sources: Oil and Natural 
Gas Sector Climate Review

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This document comprises three distinct groups of actions under 
the Clean Air Act (CAA) which are collectively intended to 
significantly reduce emissions of greenhouse gases (GHGs) and other 
harmful air pollutants from the Crude Oil and Natural Gas source 
category. First, the EPA proposes to revise the new source performance 
standards (NSPS) for GHGs and volatile organic compounds (VOCs) for the 
Crude Oil and Natural Gas source category under the CAA to reflect the 
Agency's most recent review of the feasibility and cost of reducing 
emissions from these sources. Second, the EPA proposes emissions 
guidelines (EG) under the CAA, for states to follow in developing, 
submitting, and implementing state plans to establish performance 
standards to limit GHGs from existing sources (designated facilities) 
in the Crude Oil and Natural Gas source category. Third, the EPA is 
taking several related actions stemming from the joint resolution of 
Congress, adopted on June 30, 2021 under the Congressional Review Act 
(CRA), disapproving the EPA's final rule titled, ``Oil and Natural Gas 
Sector: Emission Standards for New, Reconstructed, and Modified Sources 
Review,'' Sept. 14, 2020 (``2020 Policy Rule''). This proposal responds 
to the President's January 20, 2021, Executive order (E.O.) titled 
``Protecting Public Health and the Environment and Restoring Science to 
Tackle the Climate Crisis,'' which directed the EPA to consider taking 
the actions proposed here.

DATES: 
    Comments. Comments must be received on or before January 14, 2022. 
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 December 15, 2021.
    Public hearing: The EPA will hold a virtual public hearing on 
November 30, 2021 and December 1, 2021. See SUPPLEMENTARY INFORMATION 
for information on the hearing.

ADDRESSES: You may send comments, identified by Docket ID No. EPA-HQ-
OAR-2021-0317 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 protected]. Include Docket ID No. EPA-
HQ-OAR-2021-0317 in the subject line of the message.
     Fax: (202) 566-9744. Attention Docket ID No. EPA-HQ-OAR-
2021-0317.
     Mail: U.S. Environmental Protection Agency, EPA Docket 
Center, Docket ID No. EPA-HQ-OAR-2021-0317, 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 ``Public Participation'' 
heading of the SUPPLEMENTARY INFORMATION section of this document. Out 
of an abundance of caution for members of the public and our staff, the 
EPA Docket Center and Reading Room are closed to the public, with 
limited exceptions, to reduce the risk of transmitting COVID-19. Our 
Docket Center staff will continue to provide remote customer service 
via email, phone, and webform. We encourage the public to submit 
comments via https://www.regulations.gov/ or email, as there may be a 
delay in processing mail and faxes. Hand deliveries and couriers may be 
received by scheduled appointment only. For further information on EPA 
Docket Center services and the current status, please visit us online 
at https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: For questions about this proposed 
action, contact Ms. Karen Marsh, Sector Policies and Programs Division 
(E143-05), Office of Air Quality Planning and Standards, U.S. 
Environmental Protection Agency, Research Triangle Park, North Carolina 
27711; telephone number: (919) 541-1065; fax number: (919) 541-0516; 
and email address: [email protected] or Ms. Amy Hambrick, Sector 
Policies and Programs Division (E143-05), Office of Air Quality 
Planning and Standards, Environmental Protection Agency, Research 
Triangle Park, North Carolina 27711, telephone number: (919) 541-0964; 
facsimile number: (919) 541-3470; email address: [email protected].

SUPPLEMENTARY INFORMATION:
    Participation in virtual public hearing. Please note that the EPA 
is deviating from its typical approach for public hearings, because the 
President has declared a national emergency. Due to the current Centers 
for Disease Control and Prevention (CDC) recommendations, as well as 
state and local orders for social distancing to limit the spread of 
COVID-19, the EPA cannot hold in-person public meetings at this time.
    The public hearing will be held via virtual platform on November 
30, 2021, and December 1, 2021, and will convene at 11:00 a.m. Eastern 
Time (ET) and conclude at 9:00 p.m. ET each day. On each hearing day, 
the EPA may close a session 15 minutes after the last pre-registered 
speaker has testified if there are no additional speakers. The EPA will 
announce further details at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry. If the EPA receives a high 
volume of registrations for the public hearing, we may continue the 
public hearing on December 2, 2021. The EPA does not intend to publish 
a document in the Federal Register announcing the potential addition of 
a third day for the public hearing or any other updates to the 
information on the hearing described in this document. Please monitor 
https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry for any updates to the information described in this document, 
including information about the public hearing. For information or 
questions about the public hearing, please contact the public hearing 
team at (888) 372-8699 or by email at [email protected].
    The EPA will begin pre-registering speakers for the hearing upon 
publication of this document in the Federal Register. The EPA will 
accept registrations on an individual basis. To register to speak at 
the virtual hearing, follow the directions at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry or contact the 
public hearing team at (888) 372-

[[Page 63111]]

8699 or by email at [email protected]. The last day to pre-
register to speak at the hearing will be November 24, 2021. Prior to 
the hearing, the EPA will post a general agenda that will list pre-
registered speakers in approximate order at: https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry.
    The EPA will make every effort to follow the schedule as closely as 
possible on the day of the hearing; however, please plan for the 
hearings to run either ahead of schedule or behind schedule.
    Each commenter will have 5 minutes to provide oral testimony. The 
EPA encourages commenters to provide the EPA with a copy of their oral 
testimony electronically (via email) by emailing it to 
[email protected] and [email protected]. The EPA also recommends 
submitting the text of your oral testimony as written comments to the 
rulemaking docket.
    The EPA may ask clarifying questions during the oral presentations 
but will not respond to the presentations at that time. Written 
statements and supporting information submitted during the comment 
period will be considered with the same weight as oral testimony and 
supporting information presented at the public hearing.
    If you require the services of an interpreter or a special 
accommodation such as audio description, please pre-register for the 
hearing with the public hearing team and describe your needs by 
November 22, 2021. The EPA may not be able to arrange accommodations 
without advanced notice.
    Docket. The EPA has established a docket for this rulemaking under 
Docket ID No. EPA-HQ-OAR-2021-0317. All documents in the docket are 
listed in https://www.regulations.gov/. Although listed, some 
information is not publicly available, e.g., Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy. With the exception of such material, publicly available docket 
materials are available electronically in https://www.regulations.gov/.
    Instructions. Direct your comments to Docket ID No. EPA-HQ-OAR-
2021-0317. 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.
    The EPA is temporarily suspending its Docket Center and Reading 
Room for public visitors, with limited exceptions, to reduce the risk 
of transmitting COVID-19. Our Docket Center staff will continue to 
provide remote customer service via email, phone, and webform. We 
encourage the public to submit comments via https://www.regulations.gov/ as there may be a delay in processing mail and 
faxes. Hand deliveries or couriers will be received by scheduled 
appointment only. For further information and updates on EPA Docket 
Center services, please visit us online at https://www.epa.gov/dockets.
    The EPA continues to carefully and continuously monitor information 
from the CDC, local area health departments, and our Federal partners 
so that we can respond rapidly as conditions change regarding COVID-19.
    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-2021-0317. Note that written 
comments containing CBI submitted by mail may be delayed and no hand 
deliveries will be accepted.
    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:

ACE Affordable Clean Energy rule
AEO Annual Energy Outlook
AMEL alternate means of emissions limitation
ANGA American Natural Gas Alliance
ANSI American National Standards Institute
APCD air pollution control devices
API American Petroleum Institute
ARPA-E Advanced Research Projects Agency-Energy
ASME American Society of Mechanical Engineers

[[Page 63112]]

ASTM American Society for Testing and Materials
AVO audio, visual, olfactory
BACT best achievable control technology
BOEM Bureau of Ocean Energy Management
BLM Bureau of Land Management
BMP best management practices
boe barrels of oil equivalents
BSER best system of emission reduction
BTEX benzene, toluene, ethylbenzene, and xylenes
CAA Clean Air Act
CBI Confidential Business Information
CDC Center for Disease Control
CDX EPA's Central Data Exchange
CEDRI Compliance and Emissions Data Reporting Interface
CFR Code of Federal Regulations
CH4 methane
cm centimeter
CPI consumer price index
CPI-U consumer price index urban
CO carbon monoxide
COPD chronic obstructive pulmonary disease
CO2 carbon dioxide
CO2 Eq. carbon dioxide equivalent
COA condition of approval
COS carbonyl sulfide
CRA Congressional Review Act
CS2 carbon disulfide
CVS closed vent systems
DC direct current
DOE Department of Energy
DOI Department of the Interior
DOT Department of Transportation
EAV equivalent annualized value
EDF Environmental Defense Fund
EG emission guidelines
ECOS Environmental Council of the States
EGU electricity generating units
EIA U.S. Energy Information Administration
EJ environmental justice
EO Executive Order
EPA Environmental Protection Agency
ERT Electronic Reporting Tool
FERC The U.S. Federal Energy Regulatory Commission
fpm feet per minute
GC gas chromatograph
GHGs greenhouse gases
GHGI Inventory of U.S. Greenhouse Gas Emissions and Sinks
GHGRP Greenhouse Gas Reporting Program
GRI Gas Research Institute
GWP global warning potential
HAP hazardous air pollutant(s)
HC hydrocarbons
HFC hydrofluorocarbons
H2S hydrogen sulfide
ICR Information Collection Request
IOGCC Interstate Oil and Gas Compact Commission
IPCC Intergovernmental Panel on Climate Change
IR infrared
IRFA initial regulatory flexibility analysis
kt kilotons
kg kilograms
low-e low emission
LDAR leak detection and repair
Mcf thousand cubic feet
MMT million metric tons
MRR monitoring, recordkeeping, and reporting
MW megawatt
NAAQS National Ambient Air Quality Standards
NAICS North American Industry Classification System
NCA4 2017-2018 Fourth National Climate Assessment
NEI National Emissions Inventory
NEMS National Energy Modeling System
NESHAP National Emissions Standards for Hazardous Air Pollutants
NGL natural gas liquid
NGO non-governmental organization
NOAA National Oceanic and Atmospheric Administration
NOX nitrogen oxides
NSPS new source performance standards
NTTAA National Technology Transfer and Advancement Act
OCSLA The Outer Continental Shelf Lands Act
OAQPS Office of Air Quality Planning and Standards
OIG Office of the Inspector General
OGI optical gas imaging
OMB Office of Management and Budget
PE professional engineer
PFCs perfluorocarbons
PHMSA Pipeline and Hazardous Materials Safety Administration
PM particulate matter
PM2.5 PM with a diameter of 2.5 micrometers or less
ppb parts per billion
ppm parts per million
PRA Paperwork Reduction Act
PRD pressure release device
PRV pressure release valve
PSD Prevention of Significant Deterioration
psig pounds per square inch gauge
PTE potential to emit
PV present value
REC reduced emissions completion
RFA Regulatory Flexibility Act
RIA Regulatory Impact Analysis
RTC response to comments
SBAR Small Business Advocacy Review
SC-CH4 social cost of methane
SCF significant contribution finding
scf standard cubic feet
scfh standard cubic feet per hour
scfm standard cubic feet per minute
SF6 sulfur hexafluoride
SIP State Implementation Plan
SO2 sulfur dioxide
SOX sulfur oxides
tpy tons per year
D.C. Circuit U.S. Court of Appeals for the District of Columbia 
Circuit
TAR Tribal Authority Rule
TIP Tribal Implementation Plan
TSD technical support document
TTN Technology Transfer Network
UAS unmanned aircraft systems
UIC underground injection control
UMRA Unfunded Mandates Reform Act
U.S. United States
USGCRP U.S. Global Change Research Program
USGS U.S. Geologic Survey
VCS Voluntary Consensus Standards
VOC volatile organic compounds
VRD vapor recovery device
VRU vapor recovery unit

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

I. Executive Summary
    A. Purpose of the Regulatory Action
    B. Summary of the Major Provisions of This Regulatory Action
    C. Costs and Benefits
II. General Information
    A. Does this action apply to me?
    B. How do I obtain a copy of this document, background 
information, other related information?
III. Air Emissions From the Crude Oil and Natural Gas Sector and 
Public Health and Welfare
    A. Impacts of GHGs, VOC and SO2 Emissions on Public 
Health and Welfare
    B. Oil and Natural Gas Industry and Its Emissions
IV. Statutory Background and Regulatory History
    A. Statutory Background of CAA Sections 111(b), 111(d) and 
General Implementing Regulations
    B. What is the regulatory history and litigation background of 
NSPS and EG for the oil and natural gas industry?
    C. Effect of the CRA
V. Related Emissions Reduction Efforts
    A. Related State Actions and Other Federal Actions Regulating 
Oil and Natural Gas Sources
    B. Industry and Voluntary Actions To Address Climate Change
VI. Environmental Justice Considerations, Implications, and 
Stakeholder Outreach
    A. Environmental Justice and the Impacts of Climate Change
    B. Impacted Stakeholders
    C. Outreach and Engagement
    D. Environmental Justice Considerations
VII. Other Stakeholder Outreach
    A. Educating the Public, Listening Sessions, and Stakeholder 
Outreach
    B. EPA Methane Detection Technology Workshop
    C. How is this information being considered in this proposal?
VIII. Legal Basis for Proposal Scope
    A. Recent History of the EPA's Regulation of Oil and Gas Sources 
and Congress's Response
    B. Implications of Congress's Disapproval of the 2020 Policy 
Rule
    C. Alternative Conclusion Affirming the Legal Interpretations in 
the 2016 Rule
    D. Impacts on Regulation of Methane Emissions From Existing 
Sources
IX. Overview of Control and Control Costs
    A. Control of Methane and VOC Emissions in the Crude Oil and 
Natural Gas Source Category--Overview
    B. How does EPA evaluate control costs in this action?
X. Summary of Proposed Action for NSPS OOOOa
    A. Amendments to Fugitive Emissions Monitoring Frequency
    B. Technical and Implementation Amendments
XI. Summary of Proposed NSPS OOOOb and EG OOOOc
    A. Fugitive Emissions From Well Sites and Compressor Stations

[[Page 63113]]

    B. Storage Vessels
    C. Pneumatic Controllers
    D. Well Liquids Unloading Operations
    E. Reciprocating Compressors
    F. Centrifugal Compressors
    G. Pneumatic Pumps
    H. Equipment Leaks at Natural Gas Processing Plants
    I. Well Completions
    J. Oil Wells With Associated Gas
    K. Sweetening Units
    L. Centralized Production Facilities
    M. Recordkeeping and Reporting
    N. Prevention of Significant Deterioration and Title V 
Permitting
XII. Rationale for Proposed NSPS OOOOb and EG OOOOc
    A. Proposed Standards for Fugitive Emissions From Well Sites and 
Compressor Stations
    B. Proposed Standards for Storage Vessels
    C. Proposed Standards for Pneumatic Controllers
    D. Proposed Standards for Well Liquids Unloading Operations
    E. Proposed Standards for Reciprocating Compressors
    F. Proposed Standards for Centrifugal Compressors
    G. Proposed Standards for Pneumatic Pumps
    H. Proposed Standards for Equipment Leaks at Natural Gas 
Processing Plants
    I. Proposed Standards for Well Completions
    J. Proposed Standards for Oil Wells With Associated Gas
    K. Proposed Standards for Sweetening Units
XIII. Solicitations for Comment on Additional Emission Sources and 
Definitions
    A. Abandoned Wells
    B. Pigging Operations and Related Blowdown Activities
    C. Tank Truck Loading
    D. Control Device Efficiency and Operation
    E. Definition of Hydraulic Fracturing
XIV. State, Tribal, and Federal Plan Development for Existing 
Sources
    A. Overview
    B. Components of EG
    C. Establishing Standards of Performance in State Plans
    D. Components of State Plan Submission
    E. Timing of State Plan Submissions and Compliance Times
    F. EPA Action on State Plans and Promulgation of Federal Plans
    G. Tribes and The Planning Process Under CAA Section 111(d)
XV. Prevention of Significant Deterioration and Title V Permitting
    A. Overview
    B. Applicability of Tailoring Rule Thresholds Under the PSD 
Program
    C. Implications for Title V Program
XVI. 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?
XVII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act (PRA)
    C. Regulatory Flexibility Act (RFA)
    D. Unfunded Mandates Reform Act (UMRA)
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer and Advancement Act (NTTAA)
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations

I. Executive Summary

A. Purpose of the Regulatory Action

    This proposed rulemaking takes a significant step forward in 
mitigating climate-destabilizing pollution and protecting human health 
by reducing GHG and VOC emissions from the Oil and Natural Gas 
Industry,\1\ specifically the Crude Oil and Natural Gas source 
category.\2\ The Oil and Natural Gas Industry is the United States' 
largest industrial emitter of methane, a highly potent GHG. Human 
activity-related emissions of methane are responsible for about one 
third of the warming due to well-mixed GHGs and constitute the second 
most important warming agent arising from human activity after carbon 
dioxide (a well-mixed gas is one with an atmospheric lifetime longer 
than a year or two, which allows the gas to be mixed around the world, 
meaning that the location of emission of the gas has little importance 
in terms of its impacts). According to the Intergovernmental Panel on 
Climate Change (IPCC), strong, rapid, and sustained methane reductions 
are critical to reducing near-term disruption of the climate system and 
are a vital complement to reductions in other GHGs that are needed to 
limit the long-term extent of climate change and its destructive 
impacts. The Oil and Natural Gas Industry also emits other harmful 
pollutants in varying concentrations and amounts, including carbon 
dioxide (CO2), VOC, sulfur dioxide (SO2), 
nitrogen oxide (NOX), hydrogen sulfide (H2S), 
carbon disulfide (CS2), and carbonyl sulfide (COS), as well 
as benzene, toluene, ethylbenzene, and xylenes (this group is commonly 
referred to as ``BTEX''), and n-hexane.
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    \1\ The EPA characterizes the Oil and Natural Gas Industry 
operations as being generally composed of four 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.
    \2\ The EPA defines the Crude Oil and Natural Gas source 
category to mean (1) crude oil production, which includes the well 
and extends to the point of custody transfer to the crude oil 
transmission pipeline or any other forms of transportation; and (2) 
natural gas production, processing, transmission, and storage, which 
include the well and extend to, but do not include, the local 
distribution company custody transfer station. 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 local distribution company custody transfer station 
commonly referred to as the ``city-gate''.
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    Under the authority of CAA section 111, this rulemaking proposes 
comprehensive standards of performance for GHG emissions (in the form 
of methane limitations) and VOC emissions for new, modified, and 
reconstructed sources in the Crude Oil and Natural Gas source category, 
including the production, processing, transmission and storage 
segments. For designated facilities,\3\ this rulemaking proposes EG 
containing presumptive standards for GHG in the form of methane 
limitations. When finalized, States shall utilize these EG to submit to 
the EPA plans that establish standards of performance for designated 
facilities and provide for implementation and enforcement of such 
standards. The EPA will provide support for States in developing their 
plans to reduce methane emissions from designated facilities within the 
Crude Oil and Natural Gas source category.
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    \3\ The term ``designated facility'' means ``any existing 
facility which emits a designated pollutant and which would be 
subject to a standard of performance for that pollutant if the 
existing facility were an affected facility.'' See 40 CFR 60.21a(b).
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    The EPA is proposing these actions in accordance with its legal 
obligations and authorities following a review directed by E.O. 13990, 
``Protecting Public Health and the Environment and Restoring Science to 
Tackle the Climate Crisis,'' issued on January 20, 2021. The EPA 
intends for these proposed actions to address the far-reaching harmful 
consequences and real economic costs of climate change. According to 
the IPCC AR6 assessment, ``It is unequivocal that human influence has 
warmed the atmosphere, ocean and land. Widespread and rapid changes in 
the atmosphere, ocean, cryosphere and biosphere have occurred.'' The 
IPCC AR6 assessment states these changes have led to increases in heat 
waves and wildfire weather, reductions in air quality, more intense 
hurricanes and

[[Page 63114]]

rainfall events, and rising sea level. These changes, along with future 
projected changes, endanger the physical survival, health, economic 
well-being, and quality of life of people living in the United States 
(U.S.), especially those in the most vulnerable communities.
    Methane is both the main component of natural gas and a potent GHG. 
One ton of methane in the atmosphere has 80 times the warming impact of 
a ton of CO2, and contributes to the creation of ground-
level ozone which is another greenhouse gas. Because methane has a 
shorter lifetime than CO2, it has a smaller relative 
impact--although still significantly greater than CO2--when 
considering longer time periods. One standard metric is the 100-year 
global warming potential (GWP), which is a measure of the climate 
impact of emissions of one ton a greenhouse gas over 100 years relative 
to the impact of the emissions of one ton of CO2. Even over 
this long timeframe, methane has a 100-year GWP of almost 30. The IPCC 
AR6 assessment found that ``Over time scales of 10 to 20 years, the 
global temperature response to a year's worth of current emissions of 
SLCFs (short lived climate forcer) is at least as large as that due to 
a year's worth of CO2 emissions.'' \4\ The IPCC estimated 
that, depending on the reference scenario, collective reductions in 
these SLCFs (methane, ozone precursors, and HFCs) could reduce warming 
by 0.2 degrees Celsius ([deg]C) (more than one-third of a degree 
Fahrenheit ([deg]F) in 2040 and 0.8 [deg]C (almost 1.5 [deg]F) by the 
end of the century, which is important in the context of keeping 
warming to well below 2 [deg]C (3.6 [deg]F). As methane is the most 
important SLCF, this makes methane mitigation one of the best 
opportunities for reducing near term warming. Emissions from human 
activities have already more than doubled atmospheric methane 
concentrations since 1750, and that concentration has been growing 
larger at record rates in recent years.\5\ In the absence of additional 
reduction policies, methane emissions are projected to continue rising 
through at least 2040.
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    \4\ However, the IPCC AR6 assessment cautioned that ``The 
effects of the SLCFs decay rapidly over the first few decades after 
pulse emission. Consequently, on time scales longer than about 30 
years, the net long-term temperature effects of sectors and regions 
are dominated by CO2.''
    \5\ Naik, V., S. Szopa, B. Adhikary, P. Artaxo, T. Berntsen, 
W.D. Collins, S. Fuzzi, L. Gallardo, A. Kiendler 41 Scharr, Z. 
Klimont, H. Liao, N. Unger, P. Zanis, 2021, Short-Lived Climate 
Forcers. In: Climate Change 42 2021: The Physical Science Basis. 
Contribution of Working Group I to the Sixth Assessment Report of 
the 43 Intergovernmental Panel on Climate Change [Masson-Delmotte, 
V., P. Zhai, A. Pirani, S.L. Connors, C. 44 P[eacute]an, S. Berger, 
N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. 
Lonnoy, J.B.R. 45 Matthews, T.K. Maycock, T. Waterfield, O. 
Yelek[ccedil]i, R. Yu and B. Zhou (eds.)]. Cambridge University 46 
Press. In Press.
---------------------------------------------------------------------------

    Methane's radiative efficiency means that immediate reductions in 
methane emissions, including from sources in the Crude Oil and Natural 
Gas source category, can help reduce near-term warming. As natural gas 
is comprised primarily of methane, every natural gas leak, or 
intentional release of natural gas through venting or other processes, 
constitutes a release of methane. Reducing human-caused methane 
emissions, such as controlling natural gas leaks and releases as 
proposed in these actions, would contribute substantially to global 
efforts to limit temperature rise, aiding efforts to remain well below 
2 [deg]C above pre-industrial levels. See preamble section III for 
further discussion on the Crude Oil and Natural Gas Emissions and 
Climate Change, including discussion of the GHGs, VOCs, and 
SO2 Emissions on Public Health and Welfare.
    Methane and VOC emissions from the Crude Oil and Natural Gas source 
category result from a variety of industry operations across the supply 
chain. As natural gas moves through the necessarily interconnected 
system of exploration, production, storage, processing, and 
transmission that brings it from wellhead to commerce, emissions 
primarily result from intentional venting, unintentional gas carry-
through (e.g., vortexing from separator drain, improper liquid level 
settings, liquid level control valve on an upstream separator or 
scrubber does not seat properly at the end of an automated liquid 
dumping event, inefficient separation of gas and liquid phases occurs 
upstream of tanks allowing some gas carry-through), routine 
maintenance, unintentional fugitive emissions, flaring, malfunctions, 
abnormal process conditions, and system upsets. These emissions are 
associated with a range of specific equipment and practices, including 
leaking valves, connectors, and other components at well sites and 
compressor stations; leaks and vented emissions from storage vessels; 
releases from natural gas-driven pneumatic pumps and controllers; 
liquids unloading at well sites; and venting or under-performing 
flaring of associated gas from oil wells. But technical innovations 
have produced a range of technologies and best practices to monitor, 
eliminate or minimize these emissions, which in many cases have the 
benefit of reducing multiple pollutants at once and recovering saleable 
product. These technologies and best practices have been deployed by 
individual oil and natural gas companies, required by State 
regulations, or reflected in regulations issued by the EPA and other 
Federal agencies.
    In this action, the EPA has taken a comprehensive analysis of the 
available data from emission sources in the Crude Oil and Natural Gas 
source category and the latest available information on control 
measures and techniques to identify achievable, cost-effective measures 
to significantly reduce emissions, consistent with the requirements of 
section 111 of the CAA. If finalized and implemented, the actions 
proposed in this rulemaking would lead to significant and cost-
effective reductions in climate and health-harming pollution and 
encourage development and deployment of innovative technologies to 
further reduce this pollution in the Crude Oil and Natural Gas source 
category. The actions proposed in this rulemaking would:
     Update, strengthen, and expand current requirements under 
CAA section 111(b) for methane and VOC emissions from new, modified, 
and reconstructed facilities,
     establish new limits for methane, and VOC emissions from 
new, modified, and reconstructed facilities that are not currently 
regulated under CAA section 111(b),
     establish the first nationwide EG for States to limit 
methane pollution from existing designated facilities in the source 
category under CAA section 111(d), and
     take comment on additional sources of pollution that, with 
understanding gained from more information, may offer opportunities for 
emission reductions, which the EPA would present in a supplemental 
rulemaking proposal under both CAA section 111(b) and (d).
    In developing this proposal, the EPA drew on its own prior 
experience in regulating sources in the Crude Oil and Natural Gas 
source category under section 111 and other CAA programs; applied 
lessons learned from States' regulatory efforts, the emission reduction 
efforts of leading companies, and the EPA's long-standing voluntary 
emission reduction programs; and reviewed the latest available 
information about new and developing technologies, as well as, peer-
reviewed research from emission measurement campaigns across the U.S. 
Further, the EPA undertook extensive pre-proposal outreach to the 
public and to stakeholders, including three full days

[[Page 63115]]

of public listening sessions, roundtables with State energy and 
environmental regulators, a two-day workshop on innovative methane 
detection technologies, and a nonregulatory docket established in May 
2021 to receive written comments. Through this outreach, the EPA heard 
from diverse voices and perspectives including State and local 
governments, Tribal nations, communities affected by oil and gas 
pollution, environmental and public health organizations, and 
representatives of the oil and natural gas industry, all of which 
provided ideas and information that helped shape and inform this 
proposal.
    The EPA also considered community and environmental justice 
implications in the development of this proposal and sought to ensure 
equitable treatment and meaningful involvement of all people regardless 
of race, color, national origin, or income in the process. The EPA 
engaged and consulted representatives of frontline communities that are 
directly affected by and particularly vulnerable to the climate and 
health impacts of pollution from this source category through 
interactions such as webinars, listening sessions and meetings. These 
opportunities allowed the EPA to hear directly from the public, 
especially overburdened and underserved communities, on the development 
of the proposed rule and to factor these concerns into this proposal. 
For example, in addition to establishing EG that extend fugitive 
emission requirements to existing oil and natural gas facilities, the 
EPA is proposing to expand leak detection programs already in effect 
for new sources to include known sources of large emission events and 
proposing to require more frequent monitoring at sites with more 
emissions. The EPA is also taking comment on innovative mechanisms to 
ensure compliance and minimize emissions, including the possibility of 
providing a pathway for communities to detect and report large emitting 
events that may require follow-up and mitigation by owners and 
operators. The extensive pollution reduction measures in this proposal, 
if finalized, would collectively reduce a suite of harmful pollutants 
and their associated health impacts in communities adjacent to these 
emission sources. Further, to help ensure that the needs and 
perspectives of communities with environmental justice concerns are 
considered as States develop plans to establish and implement standards 
of performance for existing sources, the EPA is proposing to require 
that States demonstrate they have undertaken meaningful outreach and 
engagement with overburdened and underserved communities as part of 
their State plan submissions under the EPA. A full discussion of the 
Environmental Justice Considerations, Implications, and Stakeholder 
Outreach can be found in section VI of the preamble. A full discussion 
of Other Stakeholder Outreach is found in section VII of the preamble.
    As described in more detail below, the EPA recognizes that several 
States and other Federal agencies currently regulate the Oil and 
Natural Gas Industry. The EPA also recognizes that these State and 
other Federal agency regulatory programs have matured since the EPA 
began implementing the current NSPS requirements in 2012 and 2016. The 
EPA further acknowledges the technical innovations that the Oil and 
Natural Gas Industry has made during the past decade; this industry 
operates at a fast pace and changes constantly as technology evolves. 
The EPA commends these efforts and recognizes States for their 
innovative standards, alternative compliance options, and 
implementation strategies, and intends these proposed actions to build 
upon progress made by certain States and Federal agencies in reducing 
GHG and VOC emissions. See preamble section V for fuller discussion of 
Related State Actions and Other Federal Actions Regulating Oil and 
Natural Gas Sources and Industry and Voluntary Actions to Address 
Climate Change.
    The EPA believes that a broad ensemble of mutually leveraging 
efforts across all States and all Federal agencies is essential to 
meaningfully address climate change effectively. As the Federal agency 
with primary responsibility to protect human health and the 
environment, the EPA has the unique responsibility and authority to 
regulate harmful air pollutants emitted by the Crude Oil and Natural 
Gas source category. The EPA recognizes that States and other Federal 
agencies regulate in accordance with their respective legal authorities 
and within their respective jurisdictions but collectively do not fully 
and consistently address the range of sources and emission reduction 
measures contained in this proposal. Direct Federal regulation of 
methane from new, reconstructed, and modified sources in this category, 
combined with approved State plans that are consistent with the EPA's 
presumptive standards for designated facilities (existing sources), 
will help reduce both climate- and other health-harming pollution from 
a large number of sources that are either unregulated or from which 
additional, cost-effective reductions are available, level the 
regulatory playing field, and help promote technological innovation.
    Throughout this action, unless noted otherwise, the EPA is 
requesting comments on all aspects of the proposal to enable the EPA to 
develop a final rule that, consistent with our responsibilities under 
section 111 of the CAA, achieves the greatest possible reductions in 
methane and VOC emissions while remaining achievable, cost effective, 
and conducive to technological innovation. As a further step in the 
rulemaking process and to solicit additional public input, the EPA 
plans to issue a supplemental proposal and supplemental RIA for the 
supplemental proposal to provide regulatory text for the proposed NSPS 
OOOOb and EG OOOOc. In light of certain innovative elements of this 
proposed rule and the EPA's request for information that would support 
the regulation of additional sources in the Crude Oil and Natural Gas 
source category as part of this rulemaking, the EPA is considering 
including additional provisions in this supplemental proposal and RIA 
based on information and comment collected in response to this 
document.
    As noted later in this preamble, the supplemental proposal may 
address, among other issues: (1) Ways to mitigate methane from 
abandoned wells, (2) measures to reduce emissions from pipeline pigging 
operations and other pipeline blowdowns, (3) ways to minimize emissions 
from tank truck loading operations, and (4) ways to strengthen 
requirements to ensure proper operation and optimal performance of 
control devices. In addition, and as noted in the solicitations of 
comment in this document, the supplemental proposal may revisit and 
refine certain provisions of this proposal in response to information 
provided by the public. For instance, the EPA is seeking input on 
multiple aspects of the proposed approach for fugitive emissions 
monitoring at well sites, including the baseline emission threshold and 
other criteria (such as the presence of specific types of malfunction-
prone equipment) that should be used to determine whether a well site 
is required to undertake ongoing fugitive emissions monitoring; the 
methodology for calculating baseline methane emissions and whether it 
should account for malfunctions or improper operation of controls at 
storage vessels; and ways to ensure that emissions from wells owned by 
small businesses are addressed while still recognizing the greater 
challenges that small businesses with less dedicated staff and 
resources for

[[Page 63116]]

environmental compliance may have. The EPA is also seeking input on 
ways to ensure that captured associated gas is collected for a useful 
purpose rather than flared, and the feasibility of requiring broader 
use of zero-emitting technology for pneumatic pumps.
    Finally, the EPA is seeking comment and information on alternative 
measurement technologies, which we are proposing to allow in the rule. 
We have heard strong interest from various stakeholders on employing 
new tools for methane identification and quantification, particularly 
for large emission sources (commonly known as ``super-emitters''). 
Information provided in response to this proposal may be used to 
evaluate whether a change in BSER from the proposed quarterly OGI 
monitoring to a monitoring program using alternative measurement 
technologies is appropriate. Separate from the role of these 
alternative measurement technologies in a regulatory monitoring 
program, we are also soliciting comment on ways to structure a pathway 
for communities to identify large emission events which owners or 
operators would then be required to investigate, and mechanisms for the 
collection and public dissemination of this information, for possible 
further development as part of a supplemental proposal.
    This preamble includes comment solicitations/requests on several 
topics and issues. We have prepared a separate memorandum that presents 
these comment requests by section and topic as a guide to assist 
commenters in preparing comments. This memorandum can be obtained from 
the Docket for this action (see Docket ID No. EPA-HQ-OAR-2021-0317). 
The title of the memorandum is ``Standards of Performance for New, 
Reconstructed, and Modified Sources and Emissions Guidelines for 
Existing Sources: Oil and Natural Gas Sector Climate Review--Proposed 
Rule Summary of Comment Solicitations.''

B. Summary of the Major Provisions of This Regulatory Action

    This proposed rulemaking includes three distinct groups of actions 
under the CAA that are each severable from the other. First, pursuant 
to CAA 111(b)(1)(B), the EPA has reviewed, and is proposing revisions 
to, the standards of performance for the Crude Oil and Natural Gas 
source category published in 2016 and amended in 2020, codified at 40 
CFR part 60, subpart OOOOa--Standards of Performance for Crude Oil and 
Natural Gas Facilities for which Construction, Modification or 
Reconstruction Commenced After September 18, 2015 (2016 NSPS OOOOa). 
Specifically, the EPA is proposing to update, strengthen, and expand 
the current requirements under CAA section 111(b) for methane and VOC 
emissions from sources that commenced construction, modification, or 
reconstruction after November 15, 2021. These proposed standards of 
performance will be in a new subpart, 40 CFR part 60, subpart OOOOb 
(NSPS OOOOb), and include standards for emission sources previously not 
regulated under the 2016 NSPS OOOOa.
    Second, pursuant to CAA 111(d), the EPA is proposing the first 
nationwide EG for States to limit methane pollution from designated 
facilities in the Crude Oil and Natural Gas source category. The EG 
being proposed in this rulemaking will be in a new subpart, 40 CFR part 
60, subpart OOOOc (EG OOOOc). The EG are designed to inform States in 
the development, submittal, and implementation of State plans that are 
required to establish standards of performance for GHGs from their 
designated facilities in the Crude Oil and Natural Gas source category.
    Third, the EPA is taking several related actions stemming from the 
joint resolution of Congress, adopted on June 30, 2021 under the CRA, 
disapproving the EPA's final rule titled, ``Oil and Natural Gas Sector: 
Emission Standards for New, Reconstructed, and Modified Sources 
Review,'' 85 FR 57018 (Sept. 14, 2020) (``2020 Policy Rule''). As 
explained in Section X of this action (Summary of Proposed Action for 
NSPS OOOOa), the EPA is proposing amendments to the 2016 NSPS OOOOa to 
address (1) certain inconsistencies between the VOC and methane 
standards resulting from the disapproval of the 2020 Policy Rule, and 
(2) certain determinations made in the final rule titled ``Oil and 
Natural Gas Sector: Emission Standards for New, Reconstructed, and 
Modified Sources Reconsideration,'' 85 FR 57398 (September 15, 2020) 
(2020 Technical Rule), specifically with respect to fugitive emissions 
monitoring at low production well sites and gathering and boosting 
stations. With respect to the latter, as described below, the EPA is 
proposing to rescind provisions of the 2020 Technical Rule that were 
not supported by the record for that rule, or by our subsequent 
information and analysis. The regulatory text for these proposed 
amendments is included in the docket for this rulemaking at Docket ID 
EPA-HQ-OAR-2021-0317.
    In addition, in the final rule for this action, the EPA will update 
the NSPS OOOO and NSPS OOOOa provisions in the Code of Federal 
Regulations (CFR) to reflect the Congressional Review Act (CRA) 
resolution's disapproval of the final 2020 Policy Rule, specifically, 
the reinstatement of the NSPS OOOO and NSPS OOOOa requirements that the 
2020 Policy Rule repealed but that came back into effect immediately 
upon enactment of the CRA resolution. It should be noted that these 
requirements have come back into effect already even though the EPA has 
not yet updated the CFR text to reflect them.\6\ These updates to the 
CFR text are also included in the docket for this rulemaking at Docket 
ID EPA-HQ-OAR-2021-0317 for public awareness, but the EPA is not 
soliciting comment on them as they merely reflect current law. Under 5 
U.S.C. 553(b)(3)(B), notice and comment is not required ``when the 
agency for good cause finds . . . that notice and public procedure 
thereon are . . . unnecessary . . . ,'' \7\ and, as just noted, notice 
and comment is not necessary for these updates. The EPA is waiting to 
make these updates to the CFR text until the final rule simply because 
it would be more efficient and clearer to amend the CFR once at the end 
of this rulemaking process to account for all changes to the 2012 NSPS 
OOOO (77 FR 49490, August 16, 2012) and 2016 NSPS OOOOa at the same 
time.
---------------------------------------------------------------------------

    \6\ See Congressional Review Act Resolution to Disapprove EPA's 
2020 Oil and Gas Policy Rule Questions and Answers (June 30, 2021) 
available at https://www.epa.gov/system/files/documents/2021-07/qa_cra_for_2020_oil_and_gas_policy_rule.6.30.2021.pdf.
    \7\ 5 U.S.C. 553(b)(3)(B) is applicable to rules promulgated 
under CAA section 111(b), under CAA section 307(d)(1) (flush 
language at end).
---------------------------------------------------------------------------

    As CAA section 111(a)(1) requires, the standards of performance 
being proposed in this action reflect ``the degree of emission 
limitation achievable through the application of the best system of 
emission reduction [BSER] which (taking into account the cost of 
achieving such reduction and any non-air quality health and 
environmental impact and energy requirement) the Administrator 
determines has been adequately demonstrated.'' This action further 
proposes EG for designated facilities, under which States must submit 
plans which establish standards of performance that reflect the degree 
of emission limitation achievable through application of the BSER, as 
identified in the final EG. In this proposed rulemaking, we evaluated 
potential control measures available for the affected facilities, the 
emission reductions achievable through these measures, and employed 
multiple approaches to evaluate the reasonableness of control costs 
associated with the options under

[[Page 63117]]

consideration. For example, in evaluating controls for reducing VOC and 
methane emissions from new sources, we considered a control measure's 
cost-effectiveness under both a ``single pollutant cost-effectiveness'' 
approach and a ``multipollutant cost-effectiveness'' approach, to 
appropriately consider that the systems of emission reduction 
considered in this rule typically achieve reductions in multiple 
pollutants at once and secure a multiplicity of climate and public 
health benefits. For a detailed discussion of the EPA's consideration 
of this and other BSER statutory elements, please see sections IV and 
IX of this preamble.

  Table 1--Applicability Dates for Proposed Subparts Addressed in This
                             Proposed Action
------------------------------------------------------------------------
           Subpart                 Source type        Applicable dates
------------------------------------------------------------------------
40 CFR part 60, subpart OOOO  New, modified, or     After August 23,
                               reconstructed         2011 and on or
                               sources.              before September
                                                     18, 2015.
40 CFR part 60, subpart       New, modified, or     After September 18,
 OOOOa.                        reconstructed         2015 and on or
                               sources.              before November 15,
                                                     2021.
40 CFR part 60, subpart       New, modified, or     After November 15,
 OOOOb.                        reconstructed         2021.
                               sources.
40 CFR part 60, subpart       Existing sources....  On or before
 OOOOc.                                              November 15, 2021.
------------------------------------------------------------------------

1. Proposed Standards for New, Modified and Reconstructed Sources After 
November 15, 2021 (Proposed NSPS OOOOb)
    As described in sections XI and XII of this preamble, under the 
authority of CAA section 111(b)(1)(B) the EPA has reviewed the VOC, GHG 
(in the form of limitations on methane), and SO2 standards 
in the 2016 NSPS OOOOa (as amended in 2020 by the Technical Rule). 
Based on its review, the EPA is proposing revisions to the standards 
for certain emissions sources to reflect the updated BSER for those 
affected sources. Where our analyses show that the BSER for an affected 
source remains the same, the EPA is proposing to retain the current 
standard for that affected source. In addition, the EPA is proposing 
methane and VOC standards for several new sources that are currently 
unregulated. The proposed NSPS described above would apply to new, 
modified, and reconstructed emission sources across the Crude Oil and 
Natural Gas source category, including the production, processing, 
transmission, and storage segments, for which construction, 
reconstruction, or modification commenced after November 15, 2021, 
which is the date of publication of the proposed revisions to the NSPS. 
In particular, this action proposes to retain the 2016 NSPS OOOOa 
SO2 performance standard for sweetening units and the 2016 
OOOOa VOC and methane performance standards for well completions and 
centrifugal compressors; proposes revisions to strengthen the 2016 NSPS 
OOOOa VOC and methane standards addressing fugitive emissions from well 
sites and compressor stations, storage vessels, pneumatic controllers, 
reciprocating compressors, pneumatic pumps, and equipment leaks at 
natural gas processing plants; and proposes new VOC and methane 
standards for well liquids unloading operations and intermittent vent 
pneumatic controllers, and oil wells with associated gas previously not 
regulated in the 2016 NSPS OOOOa. A summary of the proposed BSER 
determination and proposed NSPS for new, modified, and reconstructed 
sources (NSPS OOOOb) is presented in Table 2. See sections XI and XII 
of this preamble for a complete discussion of BSER determination and 
proposed NSPS requirements.
    This proposal also solicits certain information relevant to the 
potential identification of additional emissions sources as affected 
facilities. Specifically, the EPA is evaluating the potential for 
establishing standards for abandoned and unplugged wells, blowdown 
emissions associated with pipeline pig launchers and receivers, and 
tank truck loading operations. While the EPA has assessed these sources 
based on currently available information, we have determined that we 
need additional information to evaluate BSER and to propose NSPS for 
these emissions sources. A full discussion of the solicitation for 
comment regarding these additional emission sources is found in section 
XIII of the preamble.
2. Proposed EG for Sources Constructed Prior to November 15, 2021 
(Proposed EG OOOOc)
    As described in sections XI and XII of this preamble, under the 
authority of CAA section 111(d), the EPA is proposing the first 
nationwide EG for GHG (in the form of methane limitations) for the 
Crude Oil and Natural Gas source category, including the production, 
processing, transmission, and storage segments (EG OOOOc). When the EPA 
establishes NSPS for a source category, the EPA is required to issue EG 
to reduce emissions of certain pollutants from existing sources in that 
same source category. In such circumstances, under CAA section 111(d), 
the EPA must issue regulations to establish procedures under which 
States submit plans to establish, implement, and enforce standards of 
performance for existing sources for certain air pollutants to which a 
Federal NSPS would apply if such existing source were a new source. 
Thus, the issuance of CAA section 111(d) final EG does not impose 
binding requirements directly on sources but instead provides 
requirements for states in developing their plans. Although State plans 
bear the obligation to establish standards of performance, under CAA 
sections 111(a)(1) and 111(d), those standards of performance must 
reflect the degree of emission limitation achievable through the 
application of the BSER as determined by the Administrator. As provided 
in section 111(d), a State may choose to take into account remaining 
useful life and other factors in applying a standard of performance to 
a particular source, consistent with the CAA, the EPA's implementing 
regulations, and the final EG.
    In this action, the EPA is proposing BSER determinations and the 
degree of limitation achievable through application of the BSER for 
certain existing equipment, processes, and activities across the Crude 
Oil and Natural Gas source category. Section XIV of this preamble 
discusses the components of EG, including the steps, requirements, and 
considerations associated with the development, submittal, and 
implementation of State, Tribal, and Federal plans, as appropriate. For 
the EG, the EPA is proposing to translate the degree of emission 
limitation achievable through application of the BSER (i.e., level of 
stringency) into presumptive standards that States may use in the 
development of State plans for specific designated facilities. By doing 
this, the EPA has formatted the proposed EG such that if a State 
chooses to adopt these

[[Page 63118]]

presumptive standards, once finalized, as the standards of performance 
in a State plan, the EPA could approve such a plan as meeting the 
requirements of CAA section 111(d) and the finalized EG, if the plan 
meets all other applicable requirements. In this way, the presumptive 
standards included in the EG serve a function similar to that of a 
model rule,\8\ because they are intended to assist States in developing 
their plan submissions by providing States with a starting point for 
standards that are based on general industry parameters and 
assumptions. The EPA believes that providing these presumptive 
standards will create a streamlined approach for States in developing 
plans and the EPA in evaluating State plans. However, the EPA's action 
on each State plan submission is carried out via rulemaking, which 
includes public notice and comment. Inclusion of presumptive standards 
in the EG does not seek to pre-determine the outcomes of any future 
rulemaking.
---------------------------------------------------------------------------

    \8\ The presumptive standards are not the same as a Federal plan 
under CAA section 111(d)(2). The EPA has an obligation to promulgate 
a Federal plan if a state fails to submit a satisfactory plan. In 
such circumstances, the final EG and presumptive standards would 
serve as a guide to the development of a Federal plan. See section 
XIV.F. for information on Federal plans.
---------------------------------------------------------------------------

    Designated facilities located in Indian country would not be 
encompassed within a State's CAA section 111(d) plan. Instead, an 
eligible Tribe that has one or more designated facilities located in 
its area of Indian country would have the opportunity, but not the 
obligation, to seek authority and submit a plan that establishes 
standards of performance for those facilities on its Tribal lands. If a 
Tribe does not submit a plan, or if the EPA does not approve a Tribe's 
plan, then the EPA has the authority to establish a Federal plan for 
that Tribe. A summary of the proposed EG for existing sources (EG 
OOOOc) for the oil and natural gas sector is presented in Table 3. See 
sections XI and XII of this preamble for a complete discussion of the 
proposed EG requirements.
    As discussed above for the proposed NSPS OOOOb, the EPA is 
considering including additional sources as affected facilities in a 
potential future supplemental rulemaking proposal \9\ under CAA section 
111(b). The EPA is also considering including these additional sources 
as designated facilities under the EG in OOOOc in a potential future 
supplemental rulemaking proposal under CAA section 111(d). As with the 
proposed NSPS OOOOb, the EPA is evaluating the potential for 
establishing EG applicable to abandoned and unplugged wells, blowdown 
emissions associated with pipeline pig launchers and receivers, and 
tank truck loading operations (assuming the EPA establishes NSPS for 
these emissions points). As described in section XIII of this preamble, 
the EPA is soliciting information to assist in this effort.
---------------------------------------------------------------------------

    \9\ A supplemental proposal would include an updated RIA.
---------------------------------------------------------------------------

3. Proposed Amendments to 2016 NSPS OOOOa, and CRA-Related CFR Updates
    The EPA is also proposing certain modifications to the 2016 NSPS 
OOOOa to address certain amendments to the VOC standards for sources in 
the production and processing segments finalized in the 2020 Technical 
Rule. Because the methane standards for the production and processing 
segments and all standards for the transmission and storage segment 
were removed from the 2016 NSPS OOOOa via the 2020 Policy Rule prior to 
the finalization of the 2020 Technical Rule, the latter amendments 
apply only to the 2016 NSPS OOOOa VOC standards for the production and 
processing segments. In this proposed rulemaking, the EPA also is 
proposing to apply some of the 2020 Technical Rule amendments to the 
methane standards for all industry segments and to VOC standards for 
the transmission and storage segment in the 2016 NSPS OOOOa. These 
amendments are associated with the requirements for well completions, 
pneumatic pumps, closed vent systems, fugitive emissions, alternative 
means of emission limitation (AMELs), onshore natural gas processing 
plants, as well as other technical clarifications and corrections. The 
EPA also is proposing to repeal the amendments in the 2020 Technical 
Rule that (1) exempted low production well sites from monitoring 
fugitive emissions and (2) changed monitoring of VOC emissions at 
gathering and boosting compressor stations from quarterly to 
semiannual, which currently apply only to VOC standards (not methane 
standards) from the production and processing segments. A summary of 
the proposed amendments to the 2016 OOOOa NSPS is presented in section 
X of this preamble.
    Lastly, in the final rule for this action, the EPA will update the 
NSPS OOOO and OOOOa provisions in the CFR to reflect the CRA 
resolution's disapproval of the final 2020 Policy Rule, specifically, 
the reinstatement of the OOOO and OOOOa requirements that the 2020 
Policy Rule repealed but that came back into effect immediately upon 
enactment of the CRA resolution. The EPA is waiting to make the updates 
to the CFR text until the final rule simply because it would be more 
efficient and clearer to amend the CFR once at the end of this 
rulemaking process to account for all changes to the 2012 NSPS OOOO and 
2016 NSPS OOOOa at the same time. In accordance with 5 U.S.C. 
553(b)(3)(B), the EPA is not soliciting comment on these updates.

 Table 2--Summary of Proposed BSER and Proposed Standards of Performance
                            for GHGS and VOC
                              [NSPS OOOOb]
------------------------------------------------------------------------
                                                   Proposed standards of
        Affected source           Proposed BSER     performance for GHGs
                                                          and VOCs
------------------------------------------------------------------------
Fugitive Emissions: Well Sites  Demonstrate        Perform survey to
 with Baseline Emissions >0 to   actual site        verify that actual
 <3 tpy \1\ Methane.             emissions are      site emissions are
                                 reflected in       reflected in
                                 calculation.       calculation.
Fugitive Emissions: Well Sites  Monitoring and     Quarterly OGI
 >=3 tpy Methane.                repair based on    monitoring following
                                 quarterly          appendix K.
                                 monitoring using   (Optional quarterly
                                 OGI \2\.           EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
(Co-proposal) Fugitive          Monitoring and     Semiannual OGI
 Emissions: Well Sites with      repair based on    monitoring following
 Baseline Emissions >=3 to <8    semiannual         appendix K.
 tpy Methane.                    monitoring using   (Optional semiannual
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.

[[Page 63119]]

 
(Co-proposal) Fugitive          Monitoring and     Quarterly OGI
 Emissions: Well Sites with      repair based on    monitoring following
 Baseline Emissions >=8 tpy      quarterly          appendix K.
 Methane.                        monitoring using   (Optional quarterly
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm \3\ defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
Fugitive Emissions: Compressor  Monitoring and     Quarterly OGI
 Stations.                       repair based on    monitoring following
                                 quarterly          appendix K.
                                 monitoring using   (Optional quarterly
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
Fugitive Emissions: Well Sites  Monitoring and     Annual OGI monitoring
 and Compressor Stations on      repair based on    following appendix
 Alaska North Slope.             annual             K. (Optional annual
                                 monitoring using   EPA Method 21
                                 OGI.               monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
Fugitive Emissions: Well Sites  (Optional)         (Optional)
 and Compressor Stations.        Screening,         Alternative
                                 monitoring, and    bimonthly screening
                                 repair based on    with advanced
                                 bimonthly          measurement
                                 screening using    technology with
                                 an advanced        annual OGI
                                 measurement        monitoring following
                                 technology and     appendix K.
                                 annual
                                 monitoring using
                                 OGI.
Storage Vessels: A Single       Capture and route  95 percent reduction
 Storage Vessel or Tank          to a control       of VOC and methane.
 Battery with PTE \4\ of 6 tpy   device.
 or More of VOC.
Pneumatic Controllers: Natural  Use of zero-       VOC and methane
 Gas Driven that Vent to the     emissions          emission rate of
 Atmosphere.                     controllers.       zero.
Pneumatic Controllers: Alaska   Installation of    Natural gas bleed
 (at sites where onsite power    low-bleed          rate no greater than
 is not available--continuous    pneumatic          6 scfh.\5\
 bleed natural gas driven).      controllers.
Pneumatic Controllers: Alaska   Monitor and        OGI monitoring and
 (at sites where onsite power    repair through     repair of emissions
 is not available--              fugitive           from controller
 intermittent natural gas        emissions          malfunctions.
 driven).                        program.
Well Liquids Unloading........  Perform liquids    Each affected well
                                 unloading with     that unloads liquids
                                 zero methane or    employ techniques or
                                 VOC emissions.     technology(ies) that
                                 If this is not     eliminate or
                                 feasible for       minimize venting of
                                 safety or          emissions during
                                 technical          liquids unloading
                                 reasons, employ    events to the
                                 best management    maximum extent.
                                 practices to
                                 minimize venting.
                                                   Co Proposal Options:
                                                   Option One--Affected
                                                    facility would be
                                                    defined as every
                                                    well that undergoes
                                                    liquids unloading.
                                                   --If the method is
                                                    one that does not
                                                    result in any
                                                    venting to the
                                                    atmosphere, maintain
                                                    records specifying
                                                    the technology or
                                                    technique and record
                                                    instances where an
                                                    unloading event
                                                    results in
                                                    emissions.
                                                   --For unloading
                                                    technologies or
                                                    techniques that
                                                    result in venting to
                                                    the atmosphere,
                                                    implement BMPs \6\
                                                    to ensure that
                                                    venting is
                                                    minimized.
                                                   --Maintain BMPs as
                                                    records, and record
                                                    instances when they
                                                    were not followed.
                                                   Option Two--Affected
                                                    facility would be
                                                    defined as every
                                                    well that undergoes
                                                    liquids unloading
                                                    using a method that
                                                    is not designed to
                                                    eliminate venting.
                                                   --Wells that utilize
                                                    non-venting methods
                                                    would not be
                                                    affected facilities
                                                    that are subject to
                                                    the NSPS OOOOb.
                                                    Therefore, they
                                                    would not have
                                                    requirements other
                                                    than to maintain
                                                    records to document
                                                    that they used non-
                                                    venting liquids
                                                    unloading methods.
                                                   --The requirements
                                                    for wells that use
                                                    methods that vent
                                                    would be the same as
                                                    described above
                                                    under Option 1.
Wet Seal Centrifugal            Capture and route  Reduce emissions by
 Compressors (except for those   emissions from     95 percent.
 located at single well sites).  the wet seal
                                 fluid degassing
                                 system to a
                                 control device
                                 or to a process.
Reciprocating Compressors       Replace the        Replace the
 (except for those located at    reciprocating      reciprocating
 single well sites).             compressor rod     compressor rod
                                 packing based on   packing when
                                 annual             measured leak rate
                                 monitoring (when   exceeds 2 scfm based
                                 measured leak      on the results of
                                 rate exceeds 2     annual monitoring or
                                 scfm \7\) or       collect and route
                                 route emissions    emissions from the
                                 to a process.      rod packing to a
                                                    process through a
                                                    closed vent system
                                                    under negative
                                                    pressure.

[[Page 63120]]

 
Pneumatic Pumps: Natural Gas    A natural gas      A natural gas
 Processing Plants.              emission rate of   emission rate of
                                 zero.              zero from diaphragm
                                                    and piston pneumatic
                                                    pumps.
Pneumatic Pumps: Production     Route diaphragm    95 percent control of
 Segment.                        and piston         diaphragm and piston
                                 pneumatic pumps    pneumatic pumps if
                                 to an existing     there is an existing
                                 control device     control or process
                                 or process.        on site. 95 percent
                                                    control not required
                                                    if (1) routed to an
                                                    existing control
                                                    that achieves less
                                                    than 95 percent or
                                                    (2) it is
                                                    technically
                                                    infeasible to route
                                                    to the existing
                                                    control device or
                                                    process.
Pneumatic Pumps: Transmission   Route diaphragm    95 percent control of
 and Storage Segment.            pneumatic pumps    diaphragm pneumatic
                                 to an existing     pumps if there is an
                                 control device     existing control or
                                 or process.        process on site. 95
                                                    percent control not
                                                    required if (1)
                                                    routed to an
                                                    existing control
                                                    that achieves less
                                                    than 95 percent or
                                                    (2) it is
                                                    technically
                                                    infeasible to route
                                                    to the existing
                                                    control device or
                                                    process.
Well Completions: Subcategory   Combination of     Applies to each well
 1 (non-wildcat and non-         REC \8\ and the    completion operation
 delineation wells).             use of a           with hydraulic
                                 completion         fracturing.
                                 combustion
                                 device.
                                                   REC in combination
                                                    with a completion
                                                    combustion device;
                                                    venting in lieu of
                                                    combustion where
                                                    combustion would
                                                    present safety
                                                    hazards.
                                                   Initial flowback
                                                    stage: Route to a
                                                    storage vessel or
                                                    completion vessel
                                                    (frac tank, lined
                                                    pit, or other
                                                    vessel) and
                                                    separator.
                                                   Separation flowback
                                                    stage: Route all
                                                    salable gas from the
                                                    separator to a flow
                                                    line or collection
                                                    system, re-inject
                                                    the gas into the
                                                    well or another
                                                    well, use the gas as
                                                    an onsite fuel
                                                    source or use for
                                                    another useful
                                                    purpose that a
                                                    purchased fuel or
                                                    raw material would
                                                    serve. If
                                                    technically
                                                    infeasible to route
                                                    recovered gas as
                                                    specified above,
                                                    recovered gas must
                                                    be combusted. All
                                                    liquids must be
                                                    routed to a storage
                                                    vessel or well
                                                    completion vessel,
                                                    collection system,
                                                    or be re-injected
                                                    into the well or
                                                    another well.
                                                   The operator is
                                                    required to have
                                                    (and use) a
                                                    separator onsite
                                                    during the entire
                                                    flowback period.
Well Completions: Subcategory   Use of a           Applies to each well
 2 (exploratory and              completion         completion operation
 delineation wells and low-      combustion         with hydraulic
 pressure wells).                device.            fracturing.
                                                   The operator is not
                                                    required to have a
                                                    separator onsite.
                                                    Either: (1) Route
                                                    all flowback to a
                                                    completion
                                                    combustion device
                                                    with a continuous
                                                    pilot flame; or (2)
                                                    Route all flowback
                                                    into one or more
                                                    well completion
                                                    vessels and commence
                                                    operation of a
                                                    separator unless it
                                                    is technically
                                                    infeasible for a
                                                    separator to
                                                    function. Any gas
                                                    present in the
                                                    flowback before the
                                                    separator can
                                                    function is not
                                                    subject to control
                                                    under this section.
                                                    Capture and direct
                                                    recovered gas to a
                                                    completion
                                                    combustion device
                                                    with a continuous
                                                    pilot flame.
                                                   For both options (1)
                                                    and (2), combustion
                                                    is not required in
                                                    conditions that may
                                                    result in a fire
                                                    hazard or explosion,
                                                    or where high heat
                                                    emissions from a
                                                    completion
                                                    combustion device
                                                    may negatively
                                                    impact tundra,
                                                    permafrost, or
                                                    waterways.
Equipment Leaks at Natural Gas  LDAR \9\ with      LDAR with OGI
 Processing Plants.              bimonthly OGI.     following procedures
                                                    in appendix K.
Oil Wells with Associated Gas.  Route associated   Route associated gas
                                 gas to a sales     to a sales line. If
                                 line. If access    access to a sales
                                 to a sales line    line is not
                                 is not             available, the gas
                                 available, the     can be used as an
                                 gas can be used    onsite fuel source,
                                 as an onsite       used for another
                                 fuel source,       useful purpose that
                                 used for another   a purchased fuel or
                                 useful purpose     raw material would
                                 that a purchased   serve, or routed to
                                 fuel or raw        a flare or other
                                 material would     control device that
                                 serve, or routed   achieves at least 95
                                 to a flare or      percent reduction in
                                 other control      methane and VOC
                                 device that        emissions.
                                 achieves at
                                 least 95 percent
                                 reduction in
                                 methane and VOC
                                 emissions.
Sweetening Units..............  Achieve SO2        Achieve required
                                 emission           minimum SO2 emission
                                 reduction          reduction
                                 efficiency.        efficiency.
------------------------------------------------------------------------
\1\ tpy (tons per year).

[[Page 63121]]

 
\2\ OGI (optical gas imaging).
\3\ ppm (parts per million).
\4\ PTE (potential to emit).
\5\ scfh (standard cubic feet per hour).
\6\ BMP (best management practices).
\7\ scfm (standard cubic feet per minute).
\8\ REC (reduced emissions completion).
\9\ LDAR (leak detection and repair).


Table 3--Summary of Proposed BSER and Proposed Presumptive Standards for
                     GHGS From Designated Facilities
                               [EG OOOOc]
------------------------------------------------------------------------
                                                    Proposed presumptive
      Designated facility         Proposed BSER      standards for GHGs
------------------------------------------------------------------------
Fugitive Emissions: Well Sites  Demonstrate        Perform survey to
 >0 to <3 tpy Methane.           actual site        verify that actual
                                 emissions are      site emissions are
                                 reflected in       reflected in
                                 calculation.       calculation.
Fugitive Emissions: Well Sites  Monitoring and     Quarterly OGI
 >=3 tpy Methane.                repair based on    monitoring following
                                 quarterly          appendix K.
                                 monitoring using   (Optional quarterly
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
(Co-proposal) Fugitive          Monitoring and     Semiannual OGI
 Emissions: Well Sites >=3 to    repair based on    monitoring following
 <8 tpy Methane.                 semiannual         appendix K.
                                 monitoring using   (Optional semiannual
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
(Co-proposal) Fugitive          Monitoring and     Quarterly OGI
 Emissions: Well Sites >=8 tpy   repair based on    monitoring following
 Methane.                        quarterly          appendix K.
                                 monitoring using   (Optional quarterly
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
Fugitive Emissions: Compressor  Monitoring and     Quarterly OGI
 Stations.                       repair based on    monitoring following
                                 quarterly          appendix K.
                                 monitoring using   (Optional quarterly
                                 OGI.               EPA Method 21
                                                    monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
Fugitive Emissions: Well Sites  Monitoring and     Annual OGI monitoring
 and Compressor Stations on      repair based on    following appendix
 Alaska North Slope.             annual             K. (Optional annual
                                 monitoring using   EPA Method 21
                                 OGI.               monitoring with 500
                                                    ppm defined as a
                                                    leak).
                                                   First attempt at
                                                    repair within 30
                                                    days of finding
                                                    fugitive emissions.
                                                    Final repair within
                                                    30 days of first
                                                    attempt.
Fugitive Emissions: Well Sites  (Optional)         (Optional)
 and Compressor Stations.        Screening,         Alternative
                                 monitoring, and    bimonthly screening
                                 repair based on    with advanced
                                 bimonthly          measurement
                                 screening using    technology with
                                 an advanced        annual OGI
                                 measurement        monitoring following
                                 technology and     appendix K.
                                 annual
                                 monitoring using
                                 OGI.
Storage Vessels: Tank Battery   Capture and route  95 percent reduction
 with PTE of 20 tpy or More of   to a control       of methane.
 Methane.                        device.
Pneumatic Controllers: Natural  Use of zero-       VOC and methane
 Gas Driven that Vent to the     emissions          emission rate of
 Atmosphere.                     controllers.       zero.
Pneumatic Controllers: Alaska   Installation of    Natural gas bleed
 (at sites where onsite power    low-bleed          rate no greater than
 is not available--continuous    pneumatic          6 scfh.
 bleed natural gas driven).      controllers.
Pneumatic Controllers: Alaska   Monitor and        OGI monitoring and
 (at sites where onsite power    repair through     repair of emissions
 is not available--              fugitive           from controller
 intermittent natural gas        emissions          malfunctions.
 driven).                        program.
Wet Seal Centrifugal            Capture and route  Reduce emissions by
 Compressors (except for those   emissions from     95 percent.
 located at single well sites).  the wet seal
                                 fluid degassing
                                 system to a
                                 control device
                                 or to a process.
Reciprocating Compressors       Replace the        Replace the
 (except for those located at    reciprocating      reciprocating
 single well sites).             compressor rod     compressor rod
                                 packing based on   packing when
                                 annual             measured leak rate
                                 monitoring (when   exceeds 2 scfm based
                                 measured leak      on the results of
                                 rate exceeds 2     annual monitoring,
                                 scfm) or route     or collect and route
                                 emissions to a     emissions from the
                                 process.           rod packing to a
                                                    process through a
                                                    closed vent system
                                                    under negative
                                                    pressure.
Pneumatic Pumps: Natural Gas    A natural gas      Zero natural gas
 Processing Plants.              emission rate of   emissions from
                                 zero.              diaphragm and piston
                                                    pneumatic pumps.
Pneumatic Pumps: Locations      Route diaphragm    95 percent control of
 Other Than Natural Gas          pumps to an        diaphragm pneumatic
 Processing Plants.              existing control   pumps if there is an
                                 device or          existing control or
                                 process.           process on site. 95
                                                    percent control not
                                                    required if (1)
                                                    routed to an
                                                    existing control
                                                    that achieves less
                                                    than 95 percent or
                                                    (2) it is
                                                    technically
                                                    infeasible to route
                                                    to the existing
                                                    control device or
                                                    process.
Equipment Leaks at Natural Gas  LDAR with          LDAR with OGI
 Processing Plants.              bimonthly OGI.     following procedures
                                                    in appendix K.

[[Page 63122]]

 
Oil Wells with Associated Gas.  Route associated   Route associated gas
                                 gas to a sales     to a sales line. If
                                 line. If access    access to a sales
                                 to a sales line    line is not
                                 is not             available, the gas
                                 available, the     can be used as an
                                 gas can be used    onsite fuel source,
                                 as an onsite       used for another
                                 fuel source,       useful purpose that
                                 used for another   a purchased fuel or
                                 useful purpose     raw material would
                                 that a purchased   serve, or routed to
                                 fuel or raw        a flare or other
                                 material would     control device that
                                 serve, or routed   achieves at least 95
                                 to a flare or      percent reduction in
                                 other control      methane and VOC
                                 device that        emissions.
                                 achieves at
                                 least 95 percent
                                 reduction in
                                 methane and VOC
                                 emissions.
------------------------------------------------------------------------

C. Costs and Benefits

    To satisfy requirements of E.O. 12866, the EPA projected the 
emissions reductions, costs, and benefits that may result from this 
proposed action. These results are presented in detail in the 
regulatory impact analysis (RIA) accompanying this proposal developed 
in response to E.O. 12866. The RIA focuses on the elements of the 
proposed rule that are likely to result in quantifiable cost or 
emissions changes compared to a baseline without the proposal that 
incorporates changes to regulatory requirements induced by the CRA 
resolution. We estimated the cost, emissions, and benefit impacts for 
the 2023 to 2035 period. We present the present value (PV) and 
equivalent annual value (EAV) of costs, benefits, and net benefits of 
this action in 2019 dollars.
    The initial analysis year in the RIA is 2023 as we assume the 
proposed rule will be finalized towards the end of 2022. The NSPS will 
take effect immediately and impact sources constructed after 
publication of the proposed rule. The EG will take longer to go into 
effect as States will need to develop implementation plans in response 
to the rule and have them approved by the EPA. We assume in the RIA 
that this process will take three years, and so EG impacts will begin 
in 2026. The final analysis year is 2035, which allows us to provide 
ten years of projected impacts after the EG is assumed to take effect.
    The cost analysis presented in the RIA reflects a nationwide 
engineering analysis of compliance cost and emissions reductions, of 
which there are two main components. The first component is a set of 
representative or model plants for each regulated facility, segment, 
and control option. The characteristics of the model plant include 
typical equipment, operating characteristics, and representative 
factors including baseline emissions and the costs, emissions 
reductions, and product recovery resulting from each control option. 
The second component is a set of projections of activity data for 
affected facilities, distinguished by vintage, year, and other 
necessary attributes (e.g., oil versus natural gas wells). Impacts are 
calculated by setting parameters on how and when affected facilities 
are assumed to respond to a particular regulatory regime, multiplying 
activity data by model plant cost and emissions estimates, differencing 
from the baseline scenario, and then summing to the desired level of 
aggregation. In addition to emissions reductions, some control options 
result in natural gas recovery, which can then be combusted in 
production or sold. Where applicable, we present projected compliance 
costs with and without the projected revenues from product recovery.
    The EPA expects climate and health benefits due to the emissions 
reductions projected under this proposed rule. The EPA estimated the 
global social benefits of CH4 emission reductions expected 
from this proposed rule using the SC-CH4 estimates presented 
in the ``Technical Support Document: Social Cost of Carbon, Methane, 
and Nitrous Oxide Interim Estimates under E.O. 13990 (IWG 2021)''. 
These SC-CH4 estimates are interim values developed under 
E.O. 13990 for use in benefit-cost analyses until updated estimates of 
the impacts of climate change can be developed based on the best 
available science and economics.
    Under the proposed rule, the EPA expects that VOC emission 
reductions will improve air quality and are likely to improve health 
and welfare associated with exposure to ozone, PM2.5, and 
HAP. Calculating ozone impacts from VOC emissions changes requires 
information about the spatial patterns in those emissions changes. In 
addition, the ozone health effects from the proposed rule will depend 
on the relative proximity of expected VOC and ozone changes to 
population. In this analysis, we have not characterized VOC emissions 
changes at a finer spatial resolution than the national total. In light 
of these uncertainties, we present an illustrative screening analysis 
in Appendix B of the RIA based on modeled oil and natural gas VOC 
contributions to ozone concentrations as they occurred in 2017 and do 
not include the results of this analysis in the estimate of benefits 
and net benefits projected from this proposal.
    The projected national-level emissions reductions over the 2023 to 
2035 period anticipated under the proposed requirements are presented 
in Table 4. Table 5 presents the PV and EAV of the projected benefits, 
costs, and net benefits over the 2023 to 2035 period under the proposed 
requirements using discount rates of 3 and 7 percent.

 Table 4--Projected Emissions Reductions Under the Proposed Rule, 2023-
                               2035 Total
------------------------------------------------------------------------
                                                    Emissions reductions
                     Pollutant                        (2023-2035 total)
------------------------------------------------------------------------
Methane (million short tons) a....................                    41
VOC (million short tons)..........................                    12
Hazardous Air Pollutant (million short tons)......                  0.48

[[Page 63123]]

 
Methane (million metric tons CO2 Eq.) b...........                   920
------------------------------------------------------------------------
a To convert from short tons to metric tons, multiply the short tons by
  0.907. Alternatively, to convert metric tons to short tons, multiply
  metric tons by 1.102.
b CO2 Eq. calculated using a global warming potential of 25.


    Table 5--Benefits, Costs, Net Benefits, and Emissions Reductions of the Proposed Rule, 2023 Through 2035
                                [Dollar Estimates in Millions of 2019 Dollars] a
----------------------------------------------------------------------------------------------------------------
                                                      3 percent discount rate         7 percent discount rate
                                                 ---------------------------------------------------------------
                                                                    Equivalent                      Equivalent
                                                   Present value   annual value    Present value   annual value
----------------------------------------------------------------------------------------------------------------
Climate Benefits b..............................         $55,000          $5,200  ..............  ..............
Net Compliance Costs............................           7,200             680           6,300             760
    Compliance Costs............................          13,000           1,200          10,000           1,200
    Product Recovery............................           5,500             520           3,900             470
Net Benefits....................................          48,000           4,500          49,000           4,500
                                                 ---------------------------------------------------------------
Non-Monetized Benefits..........................    Climate and ozone health benefits from reducing 41 million
                                                             short tons of methane from 2023 to 2035.
                                                  PM2.5 and ozone health benefits from reducing 12 million short
                                                                 tons of VOC from 2023 to 2035 c.
                                                  HAP benefits from reducing 480 thousand short tons of HAP from
                                                                           2023 to 2035.
                                                                       Visibility benefits.
                                                                    Reduced vegetation effects.
----------------------------------------------------------------------------------------------------------------
a Values rounded to two significant figures. Totals may not appear to add correctly due to rounding.
b Climate benefits are based on reductions in methane emissions and are calculated using four different
  estimates of the social cost of methane (SC-CH4) (model average at 2.5 percent, 3 percent, and 5 percent
  discount rates; 95th percentile at 3 percent discount rate). For the presentational purposes of this table, we
  show the benefits associated with the average SC-CH4 at a 3 percent discount rate, but the Agency does not
  have a single central SC-CH4 point estimate. We emphasize the importance and value of considering the benefits
  calculated using all four SC-CH4 estimates; the present value (and equivalent annual value) of the additional
  benefit estimates ranges from $22 billion to $150 billion ($2.4 billion to $14 billion) over 2023 to 2035 for
  the proposed option. Please see Table 3-5 and Table 3-7 of the RIA for the full range of SC-CH4 estimates. As
  discussed in Section 3 of the RIA, a consideration of climate benefits calculated using discount rates below 3
  percent, including 2 percent and lower, are also warranted when discounting intergenerational impacts. All net
  benefits are calculated using climate benefits discounted at 3 percent.
c A screening-level analysis of ozone benefits from VOC reductions can be found in Appendix B of the RIA, which
  is included in the docket.

II. General Information

A. Does this action apply to me?

    Categories and entities potentially affected by this action 
include:

                          Table 6--Industrial Source Categories Affected by This Action
----------------------------------------------------------------------------------------------------------------
              Category                 NAICS code 1                  Examples of regulated entities
----------------------------------------------------------------------------------------------------------------
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.
----------------------------------------------------------------------------------------------------------------
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 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).

[[Page 63124]]

B. How do I obtain a copy of this document, background information, 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 final rule and key technical 
documents at this same website. A redline version of the regulatory 
language that incorporates the proposed changes described in section X 
for NSPS OOOO and NSPS OOOOa is available in the docket for this action 
(Docket ID No. EPA-HQ-OAR-2021-0317). The EPA plans to propose the 
regulatory language for NSPS OOOOb and EG OOOOc through a supplemental 
action.

III. Air Emissions From the Crude Oil and Natural Gas Sector and Public 
Health and Welfare

A. Impacts of GHGs, VOCs and SO2 Emissions on Public Health 
and Welfare

    As noted previously, the Oil and Natural Gas Industry emits a wide 
range of pollutants, including GHGs (such as methane and 
CO2), VOCs, SO2, NOX, H2S, 
CS2, and COS. See 49 FR 2636, 2637 (January 20, 1984). As 
noted below, to this point, the EPA has focused its regulatory efforts 
on GHGs, VOC, and SO2.\10\
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    \10\ We note that the EPA's focus on GHGs (in particular 
methane), VOC, and SO2 in these analyses, does not in any 
way limit the EPA's authority to promulgate standards that would 
apply to other pollutants emitted from the Crude Oil and Natural Gas 
source category, if the EPA determines in the future that such 
action is appropriate.
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1. Climate Change Impacts From GHGs Emissions
    Elevated concentrations of GHGs are and have been warming the 
planet, leading to changes in the Earth's climate including changes in 
the frequency and intensity of heat waves, precipitation, and extreme 
weather events; rising seas; and retreating snow and ice. The changes 
taking place in the atmosphere as a result of the well-documented 
buildup of GHGs due to human activities are changing the climate at a 
pace and in a way that threatens human health, society, and the natural 
environment. Human induced GHGs, largely derived from our reliance on 
fossil fuels, are causing serious and life-threatening environmental 
and health impacts.
    Extensive additional information on climate change is available in 
the scientific assessments and the EPA documents that are briefly 
described in this section, as well as in the technical and scientific 
information supporting them. One of those documents is the EPA's 2009 
Endangerment and Cause or Contribute Findings for GHGs Under Section 
202(a) of the CAA (74 FR 66496, December 15, 2009).\11\ In the 2009 
Endangerment Findings, the Administrator found under section 202(a) of 
the CAA that elevated atmospheric concentrations of six key well-mixed 
GHGs--CO2, CH4, N2O, 
hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur 
hexafluoride (SF6)--``may reasonably be anticipated to 
endanger the public health and welfare of current and future 
generations'' (74 FR 66523, December 15, 2009), and the science and 
observed changes have confirmed and strengthened the understanding and 
concerns regarding the climate risks considered in the Finding. The 
2009 Endangerment Findings, together with the extensive scientific and 
technical evidence in the supporting record, documented that climate 
change caused by human emissions of GHGs threatens the public health of 
the U.S. population. It explained that by raising average temperatures, 
climate change increases the likelihood of heat waves, which are 
associated with increased deaths and illnesses (74 FR 66497, December 
15, 2009). While climate change also increases the likelihood of 
reductions in cold-related mortality, evidence indicates that the 
increases in heat mortality will be larger than the decreases in cold 
mortality in the U.S. (74 FR 66525, December 15, 2009). The 2009 
Endangerment Findings further explained that compared to a future 
without climate change, climate change is expected to increase 
tropospheric ozone pollution over broad areas of the U.S., including in 
the largest metropolitan areas with the worst tropospheric ozone 
problems, and thereby increase the risk of adverse effects on public 
health (74 FR 66525, December 15, 2009). Climate change is also 
expected to cause more intense hurricanes and more frequent and intense 
storms of other types and heavy precipitation, with impacts on other 
areas of public health, such as the potential for increased deaths, 
injuries, infectious and waterborne diseases, and stress-related 
disorders (74 FR 66525, December 15, 2009). Children, the elderly, and 
the poor are among the most vulnerable to these climate-related health 
effects (74 FR 66498, December 15, 2009).
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    \11\ In describing these 2009 Findings in this proposal, the EPA 
is neither reopening nor revisiting them.
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    The 2009 Endangerment Findings also documented, together with the 
extensive scientific and technical evidence in the supporting record, 
that climate change touches nearly every aspect of public welfare \12\ 
in the U.S. with resulting economic costs, including: Changes in water 
supply and quality due to increased frequency of drought and extreme 
rainfall events; increased risk of storm surge and flooding in coastal 
areas and land loss due to inundation; increases in peak electricity 
demand and risks to electricity infrastructure; and the potential for 
significant agricultural disruptions and crop failures (though offset 
to some extent by carbon fertilization). These impacts are also global 
and may exacerbate problems outside the U.S. that raise humanitarian, 
trade, and national security issues for the U.S. (74 FR 66530, December 
15, 2009).
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    \12\ The CAA states in section 302(h) that ``[a]ll language 
referring to effects on welfare includes, but is not limited to, 
effects on soils, water, crops, vegetation, manmade materials, 
animals, wildlife, weather, visibility, and climate, damage to and 
deterioration of property, and hazards to transportation, as well as 
effects on economic values and on personal comfort and well-being, 
whether caused by transformation, conversion, or combination with 
other air pollutants.'' 42 U.S.C. 7602(h).
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    In 2016, the Administrator similarly issued Endangerment and Cause 
or Contribute Findings for GHG emissions from aircraft under section 
231(a)(2)(A) of the CAA (81 FR 54422, August 15, 2016).\13\ In the 2016 
Endangerment Findings, the Administrator found that the body of 
scientific evidence amassed in the record for the 2009 Endangerment 
Findings compellingly supported a similar endangerment finding under 
CAA section 231(a)(2)(A), and also found that the science assessments 
released between the 2009 and the 2016 Findings, ``strengthen and 
further support the judgment that GHGs in the atmosphere may reasonably 
be anticipated to endanger the public health and welfare of current and 
future generations.'' (81 FR 54424, August 15, 2016).
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    \13\ In describing these 2016 Findings in this proposal, the EPA 
is neither reopening nor revisiting them.
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    Since the 2016 Endangerment Findings, the climate has continued to 
change, with new records being set for several climate indicators such 
as global average surface temperatures, GHG concentrations, and sea 
level rise. Moreover, heavy precipitation events

[[Page 63125]]

have increased in the eastern U.S. while agricultural and ecological 
drought has increased in the western U.S. along with more intense and 
larger wildfires.\14\ These and other trends are examples of the risks 
discussed the 2009 and 2016 Endangerment Findings that have already 
been experienced. Additionally, major scientific assessments continue 
to demonstrate advances in our understanding of the climate system and 
the impacts that GHGs have on public health and welfare both for 
current and future generations. These updated observations and 
projections document the rapid rate of current and future climate 
change both globally and in the U.S. These assessments include:
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    \14\ See later in this section for specific examples. An 
additional resource for indicators can be found at https://www.epa.gov/climate-indicators.
---------------------------------------------------------------------------

     U.S. Global Change Research Program's (USGCRP) 2016 
Climate and Health Assessment \15\ and 2017-2018 Fourth National 
Climate Assessment (NCA4). \16\ \17\
---------------------------------------------------------------------------

    \15\ USGCRP, 2016: The Impacts of Climate Change on Human Health 
in the United States: A Scientific Assessment. Crimmins, A., J. 
Balbus, J.L. Gamble, C.B. Beard, J.E. Bell, D. Dodgen, R.J. Eisen, 
N. Fann, M.D. Hawkins, S.C. Herring, L. Jantarasami, D.M. Mills, S. 
Saha, M.C. Sarofim, J. Trtanj, and L. Ziska, Eds. U.S. Global Change 
Research Program, Washington, DC, 312 pp.
    \16\ USGCRP, 2017: Climate Science Special Report: Fourth 
National Climate Assessment, Volume I [Wuebbles, D.J., D.W. Fahey, 
K.A. Hibbard, D.J. Dokken, B.C. Stewart, and T.K. Maycock (eds.)]. 
U.S. Global Change Research Program, Washington, DC, USA, 470 pp, 
doi: 10.7930/J0J964J6.
    \17\ USGCRP, 2018: Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, 1515 pp. doi: 10.7930/NCA4.2018.
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     IPCC's 2018 Global Warming of 1.5 [deg]C,\18\ 2019 Climate 
Change and Land,\19\ and the 2019 Ocean and Cryosphere in a Changing 
Climate \20\ assessments, as well as the 2021 IPCC Sixth Assessment 
Report (AR6).\21\
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    \18\ IPCC, 2018: Global Warming of 1.5 [deg]C. An IPCC Special 
Report on the impacts of global warming of 1.5 [deg]C above pre-
industrial levels and related global greenhouse gas emission 
pathways, in the context of strengthening the global response to the 
threat of climate change, sustainable development, and efforts to 
eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. P[ouml]rtner, 
D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. 
P[eacute]an, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. 
Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. 
Waterfield (eds.)].
    \19\ IPCC, 2019: Climate Change and Land: an IPCC special report 
on climate change, desertification, land degradation, sustainable 
land management, food security, and greenhouse gas fluxes in 
terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V. 
Masson-Delmotte, H.-O. P[ouml]rtner, D.C. Roberts, P. Zhai, R. 
Slade, S. Connors, R. van Diemen, M. Ferrat, E. Haughey, S. Luz, S. 
Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. 
Huntley, K. Kissick, M. Belkacemi, J. Malley, (eds.)].
    \20\ IPCC, 2019: IPCC Special Report on the Ocean and Cryosphere 
in a Changing Climate [H.-O. P[ouml]rtner, D.C. Roberts, V. Masson-
Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. 
Alegr[iacute]a, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer 
(eds.)].
    \21\ IPCC, 2021: Summary for Policymakers. In: Climate Change 
2021: The Physical Science Basis. Contribution of Working Group I to 
the Sixth Assessment Report of the Intergovernmental Panel on 
Climate Change [Masson-Delmotte, V., P. Zhai, A. Pirani, S.L. 
Connors, C. P[eacute]an, S. Berger, N. Caud, Y. Chen, L. Goldfarb, 
M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. 
Maycock, T. Waterfield, O. Yelek[ccedil]i, R. Yu and B. Zhou 
(eds.)]. Cambridge University Press. In Press.
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     The NAS 2016 Attribution of Extreme Weather Events in the 
Context of Climate Change,\22\ 2017 Valuing Climate Damages: Updating 
Estimation of the Social Cost of Carbon Dioxide,\23\ and 2019 Climate 
Change and Ecosystems \24\ assessments.
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    \22\ National Academies of Sciences, Engineering, and Medicine. 
2016. Attribution of Extreme Weather Events in the Context of 
Climate Change. Washington, DC: The National Academies Press. 
https://dio.org/10.17226/21852.
    \23\ National Academies of Sciences, Engineering, and Medicine. 
2017. Valuing Climate Damages: Updating Estimation of the Social 
Cost of Carbon Dioxide. Washington, DC: The National Academies 
Press. https://doi.org/10.17226/24651.
    \24\ National Academies of Sciences, Engineering, and Medicine. 
2019. Climate Change and Ecosystems. Washington, DC: The National 
Academies Press. https://doi.org/10.17226/25504.
---------------------------------------------------------------------------

     National Oceanic and Atmospheric Administration's (NOAA) 
annual State of the Climate reports published by the Bulletin of the 
American Meteorological Society,\25\ most recently in August of 2020.
---------------------------------------------------------------------------

    \25\ Blunden, J., and D.S. Arndt, Eds., 2020: State of the 
Climate in 2019. Bull. Amer. Meteor. Soc, S1-S429, https://doi.org/10.1175/2020BAMSStateoftheClimate.1.
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     EPA Climate Change and Social Vulnerability in the United 
States: A Focus on Six Impacts (2021).\26\
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    \26\ EPA. 2021. Climate Change and Social Vulnerability in the 
United States: A Focus on Six Impacts. U.S. Environmental Protection 
Agency, EPA 430-R-21-003.
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    The most recent information demonstrates that the climate is 
continuing to change in response to the human-induced buildup of GHGs 
in the atmosphere. These recent assessments show that atmospheric 
concentrations of GHGs have risen to a level that has no precedent in 
human history and that they continue to climb, primarily as a result of 
both historic and current anthropogenic emissions, and that these 
elevated concentrations endanger our health by affecting our food and 
water sources, the air we breathe, the weather we experience, and our 
interactions with the natural and built environments. For example, 
atmospheric concentrations of one of these GHGs, CO2, 
measured at Mauna Loa in Hawaii and at other sites around the world 
reached 414 ppm in 2020 (nearly 50 percent higher than pre-industrial 
levels),\27\ and has continued to rise at a rapid rate. Global average 
temperature has increased by about 1.1 degrees Celsius ([deg]C) (2.0 
degrees Fahrenheit ([deg]F)) in the 2011-2020 decade relative to 1850-
1900.\28\ The years 2014-2020 were the warmest seven years in the 1880-
2020 record, contributing to the warmest decade on record with a 
decadal temperature of 0.82 [deg]C (1.48 [deg]F) above the 20th 
century.\29\ \30\ The IPCC determined (with medium confidence) that 
this past decade was warmer than any multi-century period in at least 
the past 100,000 years.\31\ Global average sea level has risen by about 
8 inches (about 21 centimeters (cm)) from 1901 to 2018, with the rate 
from 2006 to 2018 (0.15 inches/year or 3.7 millimeters (mm)/year) 
almost twice the rate over the 1971 to 2006 period, and three times the 
rate of the 1901 to 2018 period.\32\ The rate of sea level rise over 
the 20th century was higher than in any other century in at least the 
last 2,800 years.\33\ Higher CO2 concentrations have led to 
acidification of the surface ocean in recent decades to an extent 
unusual in the past 2 million years, with negative impacts on marine 
organisms that use calcium carbonate to build shells or skeletons.\34\ 
Arctic sea ice extent continues to decline in all months of the year; 
the most rapid reductions occur in September (very likely almost a 13 
percent decrease per decade between 1979 and 2018) and are 
unprecedented in at least 1,000 years.\35\ Human-induced climate change 
has led to heatwaves and heavy precipitation becoming more frequent and 
more intense, along with increases in

[[Page 63126]]

agricultural and ecological droughts \36\ in many regions.\37\
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    \27\ https://climate.nasa.gov/vital-signs/carbon-dioxide/.
    \28\ IPCC, 2021.
    \29\ NOAA National Centers for Environmental Information, State 
of the Climate: Global Climate Report for Annual 2020, published 
online January 2021, retrieved on February 10, 2021 from https://www.ncdc.noaa.gov/sotc/global/202013.
    \30\ Blunden, J., and D.S. Arndt, Eds., 2020: State of the 
Climate in 2019. Bull. Amer. Meteor. Soc, S1-S429, https://doi.org/10.1175/2020BAMSStateoftheClimate.1.
    \31\ IPCC, 2021.
    \32\ IPCC, 2021.
    \33\ USGCRP, 2018: Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, 1515 pp. doi: 10.7930/NCA4.2018.
    \34\ IPCC, 2021.
    \35\ IPCC, 2021.
    \36\ These are drought measures based on soil moisture.
    \37\ IPCC, 2021.
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    The assessment literature demonstrates that modest additional 
amounts of warming may lead to a climate different from anything humans 
have ever experienced. The present-day CO2 concentration of 
414 ppm is already higher than at any time in the last 2 million 
years.\38\ If concentrations exceed 450 ppm, they would likely be 
higher than any time in the past 23 million years:\39\ at the current 
rate of increase of more than 2 ppm a year, this would occur in about 
15 years. While GHGs are not the only factor that controls climate, it 
is illustrative that 3 million years ago (the last time CO2 
concentrations were this high) Greenland was not yet completely covered 
by ice and still supported forests, while 23 million years ago (the 
last time concentrations were above 450 ppm) the West Antarctic ice 
sheet was not yet developed, indicating the possibility that high GHGs 
concentrations could lead to a world that looks very different from 
today and from the conditions in which human civilization has 
developed. If the Greenland and Antarctic ice sheets were to melt 
substantially, sea levels would rise dramatically--the IPCC estimated 
that over the next 2,000 years, sea level will rise by 7 to 10 feet 
even if warming is limited to 1.5 [deg]C (2.7 [deg]F), from 7 to 20 
feet if limited to 2 [deg]C (3.6 [deg]F), and by 60 to 70 feet if 
warming is allowed to reach 5 [deg]C (9 [deg]F) above preindustrial 
levels.\40\ For context, almost all of the city of Miami is less than 
25 feet above sea level, and the NCA4 stated that 13 million Americans 
would be at risk of migration due to 6 feet of sea level rise. 
Moreover, the CO2 being absorbed by the ocean has resulted 
in changes in ocean chemistry due to acidification of a magnitude not 
seen in 65 million years,\41\ putting many marine species--particularly 
calcifying species--at risk.
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    \38\ IPCC, 2021.
    \39\ IPCC, 2013.
    \40\ IPCC, 2021.
    \41\ IPCC, 2018.
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    The NCA4 found that it is very likely (greater than 90 percent 
likelihood) that by mid-century, the Arctic Ocean will be almost 
entirely free of sea ice by late summer for the first time in about 2 
million years.\42\ Coral reefs will be at risk for almost complete (99 
percent) losses with 1 [deg]C (1.8 [deg]F) of additional warming from 
today (2 [deg]C or 3.6 [deg]F since preindustrial). At this 
temperature, between 8 and 18 percent of animal, plant, and insect 
species could lose over half of the geographic area with suitable 
climate for their survival, and 7 to 10 percent of rangeland livestock 
would be projected to be lost.\43\
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    \42\ USGCRP, 2018.
    \43\ IPCC, 2018.
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    Every additional increment of temperature comes with consequences. 
For example, the half degree of warming from 1.5 to 2 [deg]C (0.9 
[deg]F of warming from 2.7 [deg]F to 3.6 [deg]F) above preindustrial 
temperatures is projected on a global scale to expose 420 million more 
people to frequent extreme heatwaves, and 62 million more people to 
frequent exceptional heatwaves (where heatwaves are defined based on a 
heat wave magnitude index which takes into account duration and 
intensity--using this index, the 2003 French heat wave that led to 
almost 15,000 deaths would be classified as an ``extreme heatwave'' and 
the 2010 Russian heatwave which led to thousands of deaths and 
extensive wildfires would be classified as ``exceptional''). It would 
increase the frequency of sea-ice-free Arctic summers from once in a 
hundred years to once in a decade. It could lead to 4 inches of 
additional sea level rise by the end of the century, exposing an 
additional 10 million people to risks of inundation, as well as 
increasing the probability of triggering instabilities in either the 
Greenland or Antarctic ice sheets. Between half a million and a million 
additional square miles of permafrost would thaw over several 
centuries. Risks to food security would increase from medium to high 
for several lower income regions in the Sahel, southern Africa, the 
Mediterranean, central Europe, and the Amazon. In addition to food 
security issues, this temperature increase would have implications for 
human health in terms of increasing ozone concentrations, heatwaves, 
and vector-borne diseases (for example, expanding the range of the 
mosquitoes which carry dengue fever, chikungunya, yellow fever, and the 
Zika virus, or the ticks which carry Lyme. babesiosis, or Rocky 
Mountain Spotted Fever).\44\ Moreover, every additional increment in 
warming leads to larger changes in extremes, including the potential 
for events unprecedented in the observational record. Every additional 
degree will intensify extreme precipitation events by about 7 percent. 
The peak winds of the most intense tropical cyclones (hurricanes) are 
projected to increase with warming. In addition to a higher intensity, 
the IPCC found that precipitation and frequency of rapid 
intensification of these storms has already increased, while the 
movement speed has decreased, and elevated sea levels have increased 
coastal flooding, all of which make these tropical cyclones more 
damaging.\45\
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    \44\ IPCC, 2018.
    \45\ IPCC, 2021.
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    The NCA4 also evaluated a number of impacts specific to the U.S. 
Severe drought and outbreaks of insects like the mountain pine beetle 
have killed hundreds of millions of trees in the western U.S. Wildfires 
have burned more than 3.7 million acres in 14 of the 17 years between 
2000 and 2016, and Federal wildfire suppression costs were about a 
billion dollars annually.\46\ The National Interagency Fire Center has 
documented U.S. wildfires since 1983, and the ten years with the 
largest acreage burned have all occurred since 2004.\47\ Wildfire smoke 
degrades air quality increasing health risks, and more frequent and 
severe wildfires due to climate change would further diminish air 
quality, increase incidences of respiratory illness, impair visibility, 
and disrupt outdoor activities, sometimes thousands of miles from the 
location of the fire. Meanwhile, sea level rise has amplified coastal 
flooding and erosion impacts, requiring the installation of costly pump 
stations, flooding streets, and increasing storm surge damages. Tens of 
billions of dollars of U.S. real estate could be below sea level by 
2050 under some scenarios. Increased frequency and duration of drought 
will reduce agricultural productivity in some regions, accelerate 
depletion of water supplies for irrigation, and expand the distribution 
and incidence of pests and diseases for crops and livestock. The NCA4 
also recognized that climate change can increase risks to national 
security, both through direct impacts on military infrastructure, but 
also by affecting factors such as food and water availability that can 
exacerbate conflict outside U.S. borders. Droughts, floods, storm 
surges, wildfires, and other extreme events stress nations and people 
through loss of life, displacement of populations, and impacts on 
livelihoods.\48\
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    \46\ USGCRP, 2018
    \47\ NIFC (National Interagency Fire Center). 2021. Total 
wildland fires and acres (1983-2020). Accessed August 2021. 
www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html.
    \48\ USGCRP, 2018.
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    Some GHGs also have impacts beyond those mediated through climate 
change. For example, elevated concentrations of carbon dioxide 
stimulate plant growth (which can be positive in the case of beneficial 
species, but negative in terms of weeds and invasive species, and can 
also lead to a reduction in plant

[[Page 63127]]

micronutrients) \49\ and cause ocean acidification. Nitrous oxide 
depletes the levels of protective stratospheric ozone.\50\
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    \49\ Ziska, L., A. Crimmins, A. Auclair, S. DeGrasse, J.F. 
Garofalo, A.S. Khan, I. Loladze, A.A. P[eacute]rez de Le[oacute]n, 
A.Showler, J. Thurston, and I. Walls, 2016: Ch. 7: Food Safety, 
Nutrition, and Distribution. The Impacts of Climate Change on Human 
Health in the United States: A Scientific Assessment. U.S. Global 
Change Research Program, Washington, DC, 189-216. http://dx.doi.org/10.7930/J0ZP4417
    \50\ WMO (World Meteorological Organization), Scientific 
Assessment of Ozone Depletion: 2018, Global Ozone Research and 
Monitoring Project--Report No. 58, 588 pp., Geneva, Switzerland, 
2018.
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    As methane is the primary GHG addressed in this proposal, it is 
relevant to highlight some specific trends and impacts specific to 
methane. Concentrations of methane reached 1879 parts per billion (ppb) 
in 2020, more than two and a half times the preindustrial concentration 
of 722 ppb.\51\ Moreover, the 2020 concentration was an increase of 
almost 13 ppb over 2019--the largest annual increase in methane 
concentrations of the period since the early 1990s, continuing a trend 
of rapid rise since a temporary pause ended in 2007.\52\ Methane has a 
high radiative efficiency--almost 30 times that of carbon dioxide per 
ppb (and therefore, 80 times as much per unit mass).\53\ In addition, 
methane contributes to climate change through chemical reactions in the 
atmosphere that produce tropospheric ozone and stratospheric water 
vapor. Human emissions of methane are responsible for about one third 
of the warming due to well-mixed GHGs, the second most important human 
warming agent after carbon dioxide.\54\ Because of the substantial 
emissions of methane, and its radiative efficiency, methane mitigation 
is one of the best opportunities for reducing near term warming.
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    \51\ Blunden et al., 2020.
    \52\ NOAA, https://gml.noaa.gov/webdata/ccgg/trends/ch4/ch4_annmean_gl.txt, accessed August 19th, 2021.
    \53\ IPCC, 2021.
    \54\ IPCC, 2021.
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    The tropospheric ozone produced by the reaction of methane in the 
atmosphere has harmful effects for human health and plant growth in 
addition to its climate effects.\55\ In remote areas, methane is an 
important precursor to tropospheric ozone formation.\56\ Approximately 
50 percent of the global annual mean ozone increase since preindustrial 
times is believed to be due to anthropogenic methane.\57\ Projections 
of future emissions also indicate that methane is likely to be a key 
contributor to ozone concentrations in the future.\58\ Unlike 
NOX and VOC, which affect ozone concentrations regionally 
and at hourly time scales, methane emissions affect ozone 
concentrations globally and on decadal time scales given methane's long 
atmospheric lifetime when compared to these other ozone precursors.\59\ 
Reducing methane emissions, therefore, will contribute to efforts to 
reduce global background ozone concentrations that contribute to the 
incidence of ozone-related health effects.\60\ The benefits of such 
reductions are global and occur in both urban and rural areas.
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    \55\ Nolte, C.G., P.D. Dolwick, N. Fann, L.W. Horowitz, V. Naik, 
R.W. Pinder, T.L. Spero, D.A. Winner, and L.H. Ziska, 2018: Air 
Quality. In Impacts, Risks, and Adaptation in the United States: 
Fourth National Climate Assessment, Volume II [Reidmiller, D.R., 
C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, pp. 512-538. doi: 10.7930/NCA4. 2018. 
CH13
    \56\ U.S. EPA. 2013. ``Integrated Science Assessment for Ozone 
and Related Photochemical Oxidants (Final Report).'' EPA-600-R-10-
076F. National Center for Environmental Assessment--RTP Division. 
Available at http://www.epa.gov/ncea/isa/.
    \57\ Myhre, G., D. Shindell, F.-M. Br[eacute]on, W. Collins, J. 
Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, 
T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: 
Anthropogenic and Natural Radiative Forcing. In: Climate Change 
2013: The Physical Science Basis. Contribution of Working Group I to 
the Fifth Assessment Report of the Intergovernmental Panel on 
Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, 
S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley 
(eds.)]. Cambridge University Press, Cambridge, United Kingdom and 
New York, NY, USA. Pg. 680.
    \58\ Ibid.
    \59\ Ibid.
    \60\ USGCRP, 2018.
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    These scientific assessments and documented observed changes in the 
climate of the planet and of the U.S. present clear support regarding 
the current and future dangers of climate change and the importance of 
GHG mitigation.
2. VOC
    Many VOC can be classified as HAP (e.g., benzene),\61\ which can 
lead to a variety of health concerns such as cancer and noncancer 
illnesses (e.g., respiratory, neurological). Further, VOC are one of 
the key precursors in the formation of ozone. Tropospheric, or ground-
level, ozone is formed through reactions of VOC and NOX in 
the presence of sunlight. Ozone formation can be controlled to some 
extent through reductions in emissions of the ozone precursors VOC and 
NOX. Recent observational and modeling studies have found 
that VOC emissions from oil and natural gas operations can impact ozone 
levels.\62\ \63\ \64\ \65\ A significantly expanded body of scientific 
evidence shows that ozone can cause a number of harmful effects on 
health and the environment. Exposure to ozone can cause respiratory 
system effects such as difficulty breathing and airway inflammation. 
For people with lung diseases such as asthma and chronic obstructive 
pulmonary disease (COPD), these effects can lead to emergency room 
visits and hospital admissions. Studies have also found that ozone 
exposure is likely to cause premature death from lung or heart 
diseases. In addition, evidence indicates that long-term exposure to 
ozone is likely to result in harmful respiratory effects, including 
respiratory symptoms and the development of asthma. People most at risk 
from breathing air containing ozone include children; people with 
asthma and other respiratory diseases; older adults; and people who are 
active outdoors, especially outdoor workers. An estimated 25.9 million 
people have asthma in the U.S., including almost 7.1 million children. 
Asthma disproportionately affects children, families with lower 
incomes, and minorities, including Puerto Ricans, Native Americans/
Alaska Natives, and African Americans.\66\
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    \61\ Benzene Integrated Risk Information System (IRIS) 
Assessment: https://cfpub.epa.gov/ncea/iris2/chemicalLanding.cfm?substance_nmbr=276.
    \62\ Benedict, K. B., Zhou, Y., Sive, B. C., Prenni, A. J., 
Gebhart, K. A., Fischer, E. V., . . . & Collett Jr, J. L. 2019. 
Volatile organic compounds and ozone in Rocky Mountain National Park 
during FRAPPE. Atmospheric Chemistry and Physics, 19(1), 499-521.
    \63\ Lindaas, J., Farmer, D. K., Pollack, I. B., Abeleira, A., 
Flocke, F., & Fischer, E. V. 2019. Acyl peroxy nitrates link oil and 
natural gas emissions to high ozone abundances in the Colorado Front 
Range during summer 2015. Journal of Geophysical Research: 
Atmospheres, 124(4), 2336-2350.
    \64\ McDuffie, E. E., Edwards, P. M., Gilman, J. B., Lerner, B. 
M., Dub[eacute], W. P., Trainer, M., . . . & Brown, S. S. 2016. 
Influence of oil and gas emissions on summertime ozone in the 
Colorado Northern Front Range. Journal of Geophysical Research: 
Atmospheres, 121(14), 8712-8729.
    \65\ Tzompa[hyphen]Sosa, Z. A., & Fischer, E. V. 2021. Impacts 
of emissions of C2[hyphen]C5 alkanes from the US oil and gas sector 
on ozone and other secondary species. Journal of Geophysical 
Research: Atmospheres, 126(1), e2019JD031935.
    \66\ National Health Interview Survey (NHIS) Data, 2011. http://www.cdc.gov/asthma/nhis/2011/data.htm.
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    In the EPA's 2020 Integrated Science Assessment (ISA) for Ozone and 
Related Photochemical Oxidants,\67\ the EPA estimates the incidence of 
air pollution effects for those health endpoints above where the ISA 
classified as either causal or likely-to-be-causal. In brief, the ISA 
for ozone found short-term (less than one month) exposures to ozone to 
be

[[Page 63128]]

causally related to respiratory effects, a ``likely to be causal'' 
relationship with metabolic effects and a ``suggestive of, but not 
sufficient to infer, a causal relationship'' for central nervous system 
effects, cardiovascular effects, and total mortality. The ISA reported 
that long-term exposures (one month or longer) to ozone are ``likely to 
be causal'' for respiratory effects including respiratory mortality, 
and a ``suggestive of, but not sufficient to infer, a causal 
relationship'' for cardiovascular effects, reproductive effects, 
central nervous system effects, metabolic effects, and total mortality. 
An example of quantified incidence of ozone health effects can be found 
in the Regulatory Impact Analysis for the Final Revised Cross-State Air 
Pollution Rule (CSAPR) Update.
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    \67\ Integrated Science Assessment (ISA) for Ozone and Related 
Photochemical Oxidants (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-20/012, 2020.
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    Scientific evidence also shows that repeated exposure to ozone can 
reduce growth and have other harmful effects on sensitive plants and 
trees. These types of effects have the potential to impact ecosystems 
and the benefits they provide.
3. SO2
    Current scientific evidence links short-term exposures to 
SO2, ranging from 5 minutes to 24 hours, with an array of 
adverse respiratory effects including bronchoconstriction and increased 
asthma symptoms. These effects are particularly important for 
asthmatics at elevated ventilation rates (e.g., while exercising or 
playing).
    Studies also show an association between short-term exposure and 
increased visits to emergency departments and hospital admissions for 
respiratory illnesses, particularly in at-risk populations including 
children, the elderly, and asthmatics.
    SO2 in the air can also damage the leaves of plants, 
decrease their ability to produce food--photosynthesis--and decrease 
their growth. In addition to directly affecting plants, SO2, 
when deposited on land and in estuaries, lakes, and streams, can 
acidify sensitive ecosystems resulting in a range of harmful indirect 
effects on plants, soils, water quality, and fish and wildlife (e.g., 
changes in biodiversity and loss of habitat, reduced tree growth, loss 
of fish species). Sulfur deposition to waterways also plays a causal 
role in the methylation of mercury.\68\
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    \68\ U.S. EPA. Integrated Science Assessment (ISA) for Oxides of 
Nitrogen and Sulfur Ecological Criteria (2008 Final Report). U.S. 
Environmental Protection Agency, Washington, DC, EPA/600/R-08/082F, 
2008.
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B. Oil and Natural Gas Industry and Its Emissions

    This section generally describes the structure of the Oil and 
Natural Gas Industry, the interconnected production, processing, 
transmission and storage, and distribution segments that move product 
from well to market, and types of emissions sources in each segment and 
the industry's emissions.
1. Oil and Natural Gas Industry--Structure
    The EPA characterizes the oil and natural gas industry's operations 
as being generally composed of four 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.\69\ \70\ The EPA 
regulates oil refineries as a separate source category; accordingly, as 
with the previous oil and gas NSPS rulemakings, 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 local distribution company custody transfer station commonly 
referred to as the ``city-gate.'' \71\
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    \69\ 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.
    \70\ While generally oil and natural gas production includes 
both onshore and offshore operations, 40 CFR part 60, subpart OOOOa 
addresses onshore operations.
    \71\ For regulatory purposes, the EPA defines the Crude Oil and 
Natural Gas source category to mean (1) Crude oil production, which 
includes the well and extends to the point of custody transfer to 
the crude oil transmission pipeline or any other forms of 
transportation; and (2) Natural gas production, processing, 
transmission, and storage, which include the well and extend to, but 
do not include, the local distribution company custody transfer 
station. The distribution segment is not part of the defined source 
category.
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a. Production Segment
    The oil and natural gas production segment includes 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). Although many wells produce a 
combination of oil and natural gas, wells can generally be grouped into 
two categories, 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 equipment and components located on the well pad may 
include, but are not limited to, wells and related casing heads; tubing 
heads; ``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.
    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 
gathering pipelines, gathering and boosting compressor stations, 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.\72\
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    \72\ 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, H2S, 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 in order to separate NGLs for use as 
feedstock for petrochemical plants, burned for space heating and 
cooking, or blended into vehicle fuel.
b. Processing Segment
    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

[[Page 63129]]

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 compressor 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.
c. Transmission and Storage Segment
    Once natural gas processing is complete, the resulting natural gas 
exits the natural gas process plant and enters the transmission and 
storage segment where it is transmitted to storage and/or distribution 
to the end user.
    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, thereby 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.
d. Distribution Segment
    The distribution segment provides the final step in delivering 
natural gas to customers.\73\ The natural gas enters the distribution 
segment from delivery points located along 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 ``city-gate.'' Natural gas distribution systems consist of over 
2 million 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 and regulating stations, which allow 
distribution companies to monitor the natural gas as it flows through 
the system.
---------------------------------------------------------------------------

    \73\ The distribution segment is not included in the definition 
of the Crude Oil and Natural Gas source category that is currently 
regulated under 40 CFR part 60, subpart OOOOa.
---------------------------------------------------------------------------

2. Oil and Natural Gas Industry--Emissions
    The oil and natural gas industry sector is the largest source of 
industrial methane emissions in the U.S.\74\ Natural gas is comprised 
primarily of methane; every natural gas leak or intentional release 
through venting or other industrial processes constitutes a release of 
methane. Methane is a potent greenhouse gas; over a 100-year timeframe, 
it is nearly 30 times more powerful at trapping climate warming heat 
than CO2, and over a 20-year timeframe, it is 83 times more 
powerful.\75\ Because methane is a powerful greenhouse gas and is 
emitted in large quantities, reductions in methane emissions provide a 
significant benefit in reducing near-term warming. Indeed, one third of 
the warming due to GHGs that we are experiencing today is due to human 
emissions of methane. Additionally, the Crude Oil and Natural Gas 
sector emits, in varying concentrations and amounts, a wide range of 
other health-harming pollutants, including VOCs, SO2, 
NOX, H2S, CS2, and COS. The year 2016 
modeling platform produced by U.S. EPA estimated about 3 million tons 
of VOC are emitted by oil and gas-related sources.\76\
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    \74\ H.R. Rep. No. 117-64, 4 (2021) (Report by the House 
Committee on Energy and Commerce concerning H.J. Res. 34, to 
disapprove the 2020 Policy Rule) (House Report).
    \75\ IPCC, 2021.
    \76\ https://www.epa.gov/sites/default/files/2020-11/documents/2016v1_emismod_tsd_508.pdf.
---------------------------------------------------------------------------

    Emissions of methane and these co-pollutants occur in every segment 
of the Crude Oil and Natural Gas source category. Many of the processes 
and equipment types that contribute to these emissions are found in 
every segment of the source category and are highly similar across 
segments. Emissions from the crude oil portion of the regulated source 
category 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 from the natural gas portion of the 
industry can occur in all segments. As natural gas moves through the 
system, emissions primarily result from intentional venting through 
normal operations, routine maintenance, unintentional fugitive 
emissions, flaring, malfunctions, and system upsets. Venting can occur 
through equipment design or operational practices, such as the 
continuous and intermittent bleed of gas from pneumatic controllers 
(devices that control gas flows, levels, temperatures, and pressures in 
the equipment). 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). Flares are commonly used 
throughout each segment in the Oil and Natural Gas Industry as a 
control device to provide pressure relief to prevent risk of explosions 
and to destroy methane, which has a high global warming potential, and 
convert it to CO2 which has a lower global warming 
potential, and to also control other air pollutants such as VOC.
    ``Super-emitting'' events, sites, or equipment, where a small 
proportion of sources account for a large proportion of overall 
emissions, can occur throughout the Oil and Natural Gas Industry and 
have been observed to occur in the equipment types and activities 
covered by this proposed action. There are a number of definitions for 
the term ``super-emitter.'' A 2018 National Academies of Sciences, 
Engineering, and Medicine report \77\ on methane discussed three 
categories of ``high-emitting'' sources:
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    \77\ https://www.nap.edu/download/24987#.

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[[Page 63130]]

     Routine or ``chronic'' high-emitting sources, which 
regularly emit at higher rates relative to ``peers'' in a sample. 
Examples include large facilities, or large emissions at smaller 
facilities caused by poor design or operational practices.
     Episodic high-emitting sources, which are typically large 
in nature and are generally intentional releases from known maintenance 
events at a facility. Examples include gas well liquids unloading, well 
workovers and maintenance activities, and compressor station or 
pipeline blowdowns.
     Malfunctioning high-emitting sources, which can be either 
intermittent or prolonged in nature and result from malfunctions and 
poor work practices. Examples include malfunctioning intermittent 
pneumatic controllers and stuck open dump valves. Another example is 
well blowout events. For example, a 2018 well blowout in Ohio was 
estimated to have emitted over 60,000 tons of methane.\78\
---------------------------------------------------------------------------

    \78\ Pandey et al. (2019). Satellite observations reveal extreme 
methane leakage from a natural gas well blowout. PNAS December 26, 
2019 116 (52) 26376-26381.
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    Super-emitters have been observed at many different scales, from 
site-level to component-level, across many research studies.\79\ 
Studies will often develop a study-specific definition such as a top 
percentile of emissions in a study population (e.g., top 10 percent), 
emissions exceeding a certain threshold (e.g., 26 kg/day), emissions 
over a certain detection threshold (e.g., 1-3 g/s) or as facilities 
with the highest proportional emission rate.\80\ For certain equipment 
types and activities, the EPA's GHG emission estimates include the full 
range of conditions, including ``super-emitters.'' For other 
situations, where data are available, emissions estimates for abnormal 
events are calculated separately and included in the Inventory of U.S. 
Greenhouse Gas Emissions and Sinks (``GHGI'') (e.g., Aliso Canyon leak 
event).\81\ Given the variability of practices and technologies across 
oil and gas systems and the occurrence of episodic events, it is 
possible that the EPA's estimates do not include all methane emissions 
from abnormal events. The EPA continues to work through its stakeholder 
process to review new data from the EPA's Greenhouse Gas Reporting 
Program (``GHGRP'') petroleum and natural gas systems source category 
(40 CFR part 98, subpart W, also referred to as ``GHGRP subpart W'') 
and research studies to assess how emissions estimates can be improved. 
Because lost gas, whether through fugitive emissions, unintentional gas 
carry through, or intentional releases, represents lost earning 
potential, the industry benefits from capturing and selling emissions 
of natural gas (and methane). Limiting super-emitters through actions 
included in this rule such as reducing fugitive emissions, using lower 
emitting equipment where feasible, and employing best management 
practices will not only reduce emissions but reduce the loss of revenue 
from this valuable commodity.
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    \79\ See for example, Brandt, A., Heath, G., Cooley, D. (2016) 
Methane leaks from natural gas systems follow extreme distributions. 
Environ. Sci. Technol., DOI: 10.1021/acs.est.6b04303; Zavala-Araiza, 
D., Alvarez, R.A., Lyon, D.R., Allen, D.T., Marchese, A.J., 
Zimmerle, D.J., & Hamburg, S.P. (2017). Super-emitters in natural 
gas infrastructure are caused by abnormal process conditions. Nature 
communications, 8, 14012; Mitchell, A., et al. (2015), Measurements 
of Methane Emissions from Natural Gas Gathering Facilities and 
Processing Plants: Measurement Results. Environmental Science & 
Technology, 49(5), 3219-3227; Allen, D., et al. (2014), Methane 
Emissions from Process Equipment at Natural Gas Production Sites in 
the United States: Pneumatic Controllers. Environmental Science & 
Technology.
    \80\ Caulton et al. (2019). Importance of Super-emitter Natural 
Gas Well Pads in the Marcellus Shale. Environ. Sci. Technol. 2019, 
53, 4747-4754; Zavala-Araiza, D., Alvarez, R., Lyon, D, et al. 
(2016). Super-emitters in natural gas infrastructure are caused by 
abnormal process conditions. Nat Commun 8, 14012 (2017). https://www.nature.com/articles/ncomms14012; Lyon, et al. (2016). Aerial 
Surveys of Elevated Hydrocarbon Emissions from Oil and Gas 
Production Sites. Environ. Sci. Technol. 2016, 50, 4877-4886. 
https://pubs.acs.org/doi/10.1021/acs.est.6b00705; and Zavala-Araiza 
D, et al. (2015). Toward a functional definition of methane 
superemitters: Application to natural gas production sites. 49 
ENVTL. SCI. & TECH. 8167, 8168 (2015). https://pubs.acs.org/doi/10.1021/acs.est.5b00133.
    \81\ The EPA's emission estimates in the GHGI are developed with 
the best data available at the time of their development, including 
data from the Greenhouse Gas Reporting Program (GHGRP) in 40 CFR 
part 98, subpart W, and from recent research studies. GHGRP subpart 
W emissions data used in the GHGI are quantified by reporters using 
direct measurements, engineering calculations, or emission factors, 
as specified by the regulation. The EPA has a multi-step data 
verification process for GHGRP subpart W data, including automatic 
checks during data-entry, statistical analyses on completed reports, 
and staff review of the reported data. Based on the results of the 
verification process, the EPA follows up with facilities to resolve 
mistakes that may have occurred.
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    Below we provide estimated emissions of methane, VOC, and 
SO2 from Oil and Natural Gas Industry operation sources.
    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 GHGI in fulfillment of 
commitments under the United Nations Framework Convention on Climate 
Change. The GHGI, which includes recent trends, is organized by 
industrial sector. The oil and natural gas production, natural gas 
processing, and natural gas transmission and storage sectors emit 28 
percent of U.S. anthropogenic methane. Table 7 below presents total 
U.S. anthropogenic methane emissions for the years 1990, 2010, and 
2019.
    In accordance with the practice of the EPA GHGI, the EPA GHGRP, and 
international reporting standards under the UN Framework Convention on 
Climate Change, the 2007 IPCC Fourth Assessment Report value of the 
methane 100-year GWP is used for weighting emissions in the following 
tables. The 100-year GWP value of 25 for methane indicates that one ton 
of methane has approximately as much climate impact over a 100-year 
period as 25 tons of carbon dioxide. The most recent IPCC AR6 
assessment has estimated a slightly larger 100-year GWP of methane of 
almost 30 (specifically, either 27.2 or 29.8 depending on whether the 
value includes the carbon dioxide produced by the oxidation of methane 
in the atmosphere). As mentioned earlier, because methane has a shorter 
lifetime than carbon dioxide, the emissions of a ton of methane will 
have more impact earlier in the 100-year timespan and less impact later 
in the 100-year timespan relative to the emissions of a 100-year GWP-
equivalent quantity of carbon dioxide: When using the AR6 20-year GWP 
of 81, which only looks at impacts over the next 20 years, the total US 
emissions of methane in 2019 would be equivalent to about 2140 MMT 
CO2.

                                    Table 7--U.S. Methane Emissions by Sector
                          [Million metric tons carbon dioxide equivalent (MMT CO2 EQ.)]
----------------------------------------------------------------------------------------------------------------
                             Sector                                    1990            2010            2019
----------------------------------------------------------------------------------------------------------------
Oil and Natural Gas Production, and Natural Gas Processing and               189             176             182
 Transmission and Storage.......................................
Landfills.......................................................             177             124             114
Enteric Fermentation............................................             165             172             179

[[Page 63131]]

 
Coal Mining.....................................................              96              82              47
Manure Management...............................................              37              55              62
Other Oil and Gas Sources.......................................              46              17              15
Wastewater Treatment............................................              20              19              18
Other Methane Sources \82\......................................              46              47              42
                                                                 -----------------------------------------------
    Total Methane Emissions.....................................             777             692             660
----------------------------------------------------------------------------------------------------------------
Emissions from the Inventory of United States Greenhouse Gas Emissions and Sinks: 1990-2019 (published April 14,
  2021), calculated using GWP of 25. Note: Totals may not sum due to rounding.

    Table 8 below presents total methane emissions from natural gas 
production through transmission and storage and petroleum production, 
for years 1990, 2010, and 2019, in MMT CO2 Eq. (or million 
metric tons CO2 Eq.) of methane.
---------------------------------------------------------------------------

    \82\ Other sources include rice cultivation, forest land, 
stationary combustion, abandoned oil and natural gas wells, 
abandoned coal mines, mobile combustion, composting, and several 
sources emitting less than 1 MMT CO2 Eq. in 2019.

                     Table 8--U.S. Methane Emissions From Natural Gas and Petroleum Systems
                                                  [MMT CO2 EQ.]
----------------------------------------------------------------------------------------------------------------
                             Sector                                    1990            2010            2019
----------------------------------------------------------------------------------------------------------------
Natural Gas Production..........................................              63              97              94
Natural Gas Processing..........................................              21              10              12
Natural Gas Transmission and Storage............................              57              30              37
Petroleum Production............................................              48              39              38
----------------------------------------------------------------------------------------------------------------
Emissions from the Inventory of United States Greenhouse Gas Emissions and Sinks: 1990-2019 (published April 14,
  2021), calculated using GWP of 25. Note: Totals may not sum due to rounding.

    Global GHG Emissions. For additional background information and 
context, we used 2018 World Resources Institute Climate Watch data to 
make comparisons between U.S. oil and natural gas production and 
natural gas processing and transmission and storage emissions and the 
emissions inventories of entire countries and regions.\83\ The U.S. 
methane emissions from oil and natural gas production and natural gas 
processing and transmission and storage constitute 0.4 percent of total 
global emissions of all GHGs (48,601 MMT CO2 Eq.) from all sources.\84\ 
Ranking U.S. emissions of methane from oil and natural gas production 
and natural gas processing and transmission and storage against total 
GHG emissions for entire countries (using 2018 Climate Watch data), 
shows that these emissions are comparatively large as they exceed the 
national-level emissions totals for all GHGs and all anthropogenic 
sources for Colombia, the Czech Republic, Chile, Belgium, and over 160 
other countries. What that means is that the U.S. emits more of a 
single GHG--methane--from a single sector--the oil and gas sector--than 
the total combined GHGs emitted by 164 out of 194 total countries. 
Furthermore, U.S. emissions of methane from oil and natural gas 
production and natural gas processing and transmission and storage are 
greater than the sum of total emissions of 64 of the lowest-emitting 
countries and territories, using the 2018 Climate Watch data set.
---------------------------------------------------------------------------

    \83\ The Climate Watch figures presented here come from the PIK 
PRIMAP-hist dataset included on Climate Watch. The PIK PRIMAP-hist 
dataset combines the United Nations Framework Convention on Climate 
Change (UNFCCC) reported data where available and fills gaps with 
other sources. It does not include land use change and forestry but 
covers all other sectors. https://www.climatewatchdata.org/ghg-emissions?end_year=2018&source=PIK&start_year=1990.
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    As illustrated by the domestic and global GHGs comparison data 
summarized above, the collective GHG emissions from the Crude Oil and 
Natural Gas source category are significant, whether the comparison is 
domestic (where this sector is the largest source of methane emissions, 
accounting for 28 percent of U.S. methane and 3 percent of total U.S. 
emissions of all GHGs), global (where this sector, accounting for 0.4 
percent of all global GHG emissions, emits more than the total national 
emissions of over 160 countries, and combined emissions of over 60 
countries), or when both the domestic and global GHG emissions 
comparisons are viewed in combination. Consideration of the global 
context is important. GHG emissions from U.S. Oil and Natural Gas 
production and natural gas processing and transmission and storage will 
become globally well-mixed in the atmosphere, and thus will have an 
effect on the U.S. regional climate, as well as the global climate as a 
whole for years and indeed many decades to come. No single GHG source 
category dominates on the global scale. While the Crude Oil and Natural 
Gas source category, like many (if not all) individual GHG source 
categories, could appear small in comparison to total emissions, in 
fact, it is a very important contributor in terms of both absolute 
emissions, and in comparison to other source categories globally or 
within the U.S.
    The IPCC AR6 assessment determined that ``From a physical science 
perspective, limiting human-induced global warming to a specific level 
requires limiting cumulative CO2 emissions, reaching at 
least net zero CO2 emissions, along with strong reductions 
in other GHG emissions.'' The report also singled out the importance of 
``strong and sustained CH4 emission reductions'' in part due 
to the short lifetime of methane leading to the near-term cooling from 
reductions in methane emissions, which can offset the warming that will 
result due to reductions in emissions of cooling aerosols such as 
SO2. Therefore, reducing methane emissions globally is an 
important facet in any strategy to limit warming. In the oil and gas 
sector,

[[Page 63132]]

methane reductions are highly achievable and cost-effective using 
existing and well-known solutions and technologies that actually result 
in recovery of saleable product.
    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. Tables 9 and 10 below present total U.S. 
VOC and SO2 emissions by sector, respectively, for the year 
2017, in kilotons (kt) (or thousand metric tons). The oil and natural 
gas sector represents the top anthropogenic U.S. sector for VOC 
emissions after removing the biogenics and wildfire sectors in Table 9 
(about 20% of the total VOC emitting by anthropogenic sources). About 
2.5 percent of the total U.S. anthropogenic SO2 comes from 
the oil and natural gas sector.

                  Table 9--U.S. VOC Emissions by Sector
                                  [kt]
------------------------------------------------------------------------
                         Sector                                2017
------------------------------------------------------------------------
Biogenics--Vegetation and Soil..........................          25,823
Fires--Wildfires........................................           4,578
Oil and Natural Gas Production, and Natural Gas                    2,504
 Processing and Transmission............................
Fires--Prescribed Fires.................................           2,042
Solvent--Consumer and Commercial Solvent Use............           1,610
Mobile--On-Road non-Diesel Light Duty Vehicles..........           1,507
Mobile--Non-Road Equipment--Gasoline....................           1,009
Other VOC Sources \85\..................................           4,045
                                                         ---------------
    Total VOC Emissions.................................          43,118
------------------------------------------------------------------------
Emissions from the 2017 NEI (released April 2020). Note: Totals may not
  sum due to rounding.


                 Table 10--U.S. SO2 Emissions by Sector
                                  [kt]
------------------------------------------------------------------------
                         Sector                                2017
------------------------------------------------------------------------
Fuel Combustion--Electric Generation--Coal..............           1,319
Fuel Combustion--Industrial Boilers, Internal Combustion             212
 Engines--Coal..........................................
Mobile--Commercial Marine Vessels.......................             183
Industrial Processes--Not Elsewhere Classified..........             138
Fires--Wildfires........................................             135
Industrial Processes--Chemical Manufacturing............             123
Oil and Natural Gas Production and Natural Gas                        65
 Processing and Transmission............................
Other SO2 Sources \86\..................................             551
                                                         ---------------
    Total SO2 Emissions.................................           2,726
------------------------------------------------------------------------
Emissions from the 2017 NEI (released April 2020). Note: Totals may not
  sum due to rounding.

    Table 11 below presents total VOC and SO2 emissions from 
oil and natural gas production through transmission and storage, for 
the year 2017, in kt. The contribution to the total anthropogenic VOC 
emissions budget from the oil and gas sector has been increasing in 
recent NEI cycles. In the 2017 NEI, the oil and gas sector makes up 
about 25 percent of the total VOC emissions from anthropogenic sources. 
The SO2 emissions have been declining in just about every 
anthropogenic sector, but the oil and gas sector is an exception where 
SO2 emissions have been slightly increasing or remaining 
steady in some cases in recent years.
---------------------------------------------------------------------------

    \85\ Other sources include remaining sources emitting less than 
1,000 kt VOC in 2017.
    \86\ Other sources include remaining sources emitting less than 
100 kt SO2 in 2017.

   Table 11--U.S. VOC and SO2 Emissions From Natural Gas and Petroleum
                                 Systems
                                  [kt]
------------------------------------------------------------------------
                 Sector                         VOC             SO2
------------------------------------------------------------------------
Oil and Natural Gas Production..........           2,478              41
Natural Gas Processing..................              12              23
Natural Gas Transmission and Storage....              14               1
------------------------------------------------------------------------
Emissions from the 2017 NEI, (published April 2020), in kt (or thousand
  metric tons). Note: Totals may not sum due to rounding.


[[Page 63133]]

IV. Statutory Background and Regulatory History

A. Statutory Background of CAA Sections 111(b), 111(d) and General 
Implementing Regulations

    The EPA's authority for this rule is CAA section 111, which governs 
the establishment of standards of performance for stationary sources. 
This section requires the EPA to list source categories to be 
regulated, establish standards of performance for air pollutants 
emitted by new sources in that source category, and establish EG for 
States to establish standards of performance for certain pollutants 
emitted by existing sources in that source category.
    Specifically, CAA section 111(b)(1)(A) requires that a source 
category be included on the list for regulation if, ``in [the EPA 
Administrator's] judgment it causes, or contributes significantly to, 
air pollution which may reasonably be anticipated to endanger public 
health or welfare.'' This determination is commonly referred to as an 
``endangerment finding'' and that phrase encompasses both of the 
``causes or contributes significantly to'' component and the ``endanger 
public health or welfare'' component of the determination. Once a 
source category is listed, CAA section 111(b)(1)(B) requires that the 
EPA propose and then promulgate ``standards of performance'' for new 
sources in such source category. 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 which 
(taking into account the cost of achieving such reduction and any non-
air quality health and environmental impact and energy requirements) 
the Administrator determines has been adequately demonstrated.'' As 
long recognized by the D.C. Circuit, ``[b]ecause Congress did not 
assign the specific weight the Administrator should accord each of 
these factors, the Administrator is free to exercise his discretion in 
this area.'' New York v. Reilly, 969 F.2d 1147, 1150 (D.C. Cir. 1992). 
See also Lignite Energy Council v. EPA, 198 F.3d 930, 933 (D.C. Cir. 
1999) (``Lignite Energy Council'') (``Because section 111 does not set 
forth the weight that be [sic] should assigned to each of these 
factors, we have granted the agency a great degree of discretion in 
balancing them'').
    In determining whether a given system of emission reduction 
qualifies as ``the best system of emission reduction . . . adequately 
demonstrated,'' or ``BSER,'' CAA section 111(a)(1) requires that the 
EPA take into account, among other factors, ``the cost of achieving 
such reduction.'' As described in the proposal \87\ for the 2016 Rule 
(85 FR 35824, June 3, 2016), the U.S. Court of Appeals for the District 
of Columbia Circuit (the D.C. Circuit) has stated that in light of this 
provision, the EPA may not adopt a standard the cost of which would be 
``exorbitant,'' \88\ ``greater than the industry could bear and 
survive,'' \89\ ``excessive,'' \90\ or ``unreasonable.'' \91\ These 
formulations appear to be synonymous, and for convenience, in this 
rulemaking, as in previous rulemakings, we will use reasonableness as 
the standard, so that a control technology may be considered the ``best 
system of emission reduction . . . adequately demonstrated'' if its 
costs are reasonable, but cannot be considered the BSER if its costs 
are unreasonable. See 80 FR 64662, 64720-21 (October 23, 2015).
---------------------------------------------------------------------------

    \87\ 80 FR 56593, 56616 (September 18, 2015).
    \88\ Lignite Energy Council, 198 F.3d at 933.
    \89\ Portland Cement Ass'n v. EPA, 513 F.2d 506, 508 (D.C. Cir. 
1975).
    \90\ Sierra Club v. Costle, 657 F.2d 298, 343 (D.C. Cir. 1981).
    \91\ Id.
---------------------------------------------------------------------------

    CAA section 111(a) does not provide specific direction regarding 
what metric or metrics to use in considering costs, affording the EPA 
considerable discretion in choosing a means of cost consideration.\92\ 
In this rulemaking, we evaluated whether a control cost is reasonable 
under a number of approaches that we find appropriate for assessing the 
types of controls at issue. For example, in evaluating controls for 
reducing VOC and methane emissions from new sources, we considered a 
control's cost effectiveness under both a ``single pollutant cost-
effectiveness'' approach and a ``multipollutant cost-effectiveness'' 
approach, in order to appropriately take into account that the systems 
of emission reduction considered in this rule typically achieve 
reductions in multiple pollutants at once and secure a multiplicity of 
climate and public health benefits.\93\ We also evaluated costs at a 
sector level by assessing the projected new capital expenditures 
required under the proposal (compared to overall new capital 
expenditures by the sector) and the projected compliance costs 
(compared to overall annual revenue for the sector) if the rule were to 
require such controls. For a detailed discussion of these cost 
approaches, please see section IX of the proposal preamble.
---------------------------------------------------------------------------

    \92\ 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).
    \93\ We believe that both the single and multipollutant 
approaches are appropriate for assessing the reasonableness of the 
multipollutant controls considered in this action. The EPA has 
considered similar approaches in the past when considering multiple 
pollutants that are controlled by a given control option. See e.g., 
80 FR 56616-56617; 73 FR 64079-64083 and EPA Document ID Nos. EPA-
HQ-OAR-2004-0022-0622, EPA-HQ-OAR-2004-0022-0447, EPA-HQ-OAR-2004-
0022-0448.
---------------------------------------------------------------------------

    As defined in CAA section 111(a), the ``standard of performance'' 
that the EPA develops, based on the BSER, is expressed as a performance 
level (typically, a rate-based standard). CAA section 111(b)(5) 
precludes the EPA from prescribing a particular technological system 
that must be used to comply with a standard of performance. Rather, 
sources can select any measure or combination of measures that will 
achieve the standard.
    CAA section 111(h)(1) authorizes the Administrator to promulgate 
``a design, equipment, work practice, or operational standard, or 
combination thereof'' if in his or her judgment, ``it is not feasible 
to prescribe or enforce a standard of performance.'' CAA section 
111(h)(2) provides the circumstances under which prescribing or 
enforcing a standard of performance is ``not feasible,'' such as, when 
the pollutant cannot be emitted through a conveyance designed to emit 
or capture the pollutant, or when there is no practicable measurement 
methodology for the particular class of sources.\94\ CAA section 
111(b)(1)(B) requires the EPA to ``at least every 8 years review and, 
if appropriate, revise'' performance standards unless the 
``Administrator determines that such review is not appropriate in light 
of readily available information on the efficacy'' of the standard.
---------------------------------------------------------------------------

    \94\ The EPA notes that design, equipment, work practice or 
operational standards established under CAA section 111(h) (commonly 
referred to as ``work practice standards'') reflect the ``best 
technological system of continuous emission reduction'' and that 
this phrasing differs from the ``best system of emission reduction'' 
phrase in the definition of ``standard of performance'' in CAA 
section 111(a)(1). Although the differences in these phrases may be 
meaningful in other contexts, for purposes of evaluating the sources 
and systems of emission reduction at issue in this rulemaking, the 
EPA has applied these concepts in an essentially comparable manner.
---------------------------------------------------------------------------

    As mentioned above, once the EPA lists a source category under CAA 
section 111(b)(1)(A), CAA section 111(b)(1)(B) provides the EPA 
discretion to determine the pollutants and sources to be regulated. In 
addition, concurrent with the 8-year review (and though not a mandatory 
part of the 8-year review), the EPA may examine whether to add 
standards for pollutants or emission

[[Page 63134]]

sources not currently regulated for that source category.
    Once the EPA establishes NSPS in a particular source category, the 
EPA is required in certain circumstances to issue EG to reduce 
emissions from existing sources in that same source category. 
Specifically, CAA section 111(d) requires that the EPA prescribe 
regulations to establish procedures under which States submit plans to 
establish, implement, and enforce standards of performance for existing 
sources for certain air pollutants to which a Federal NSPS would apply 
if such existing source were a new source. The EPA addresses this CAA 
requirement both through its promulgation of general implementing 
regulations for section 111(d) as well as specific EG. The EPA first 
published general implementing regulations in 1975, 40 FR 53340 
(November 17, 1975) (codified at 40 CFR part 60, subpart B), and has 
revised its section 111(d) implementing regulations several times, most 
recently on July 8, 2019, 84 FR 32520 (codified at 40 CFR part 60, 
subpart Ba).\95\ In accordance with CAA section 111(d), States are 
required to submit plans pursuant to these regulations to establish 
standards of performance for existing sources for any air pollutant: 
(1) The emission of which is subject to a Federal NSPS; and (2) which 
is neither a pollutant regulated under CAA section 108(a) (i.e., 
criteria pollutants such as ground-level ozone and particulate matter, 
and their precursors, like VOC) \96\ or a HAP regulated under CAA 
section 112. See also definition of ``designated pollutant'' in 40 CFR 
60.21a(a). The EPA's general implementing regulations use the term 
``designated facility'' to identify those existing sources that may be 
subject to regulation under this provision of CAA section 111(d). See 
40 CFR 60.21a(b).
---------------------------------------------------------------------------

    \95\ Subpart Ba provides for the applicability of its provisions 
upon final publication of an EG if such EG is published after July 
8, 2019. Sec.  60.20a(a). The EPA acknowledges that the D.C. Circuit 
has vacated certain timing provisions within subpart Ba. Am. Lung 
Assoc. v. EPA, 985 F.3d 914 (D.C. Cir. 2021), petition for cert. 
pending, No. 20-1778 (filed June 23, 2001) (Am. Lung Assoc.). 
However, the court did not vacate the applicability provision, 
therefore subpart Ba applies to any EG finalized from this proposal. 
The Agency plans to undertake rulemaking to address the provisions 
vacated under the court's decision in the near future.
    \96\ VOC are not listed as CAA section 108(a) pollutants, but 
they are regulated precursors to photochemical oxidants (e.g., 
ozone) and particulate matter (PM), both of which are listed CAA 
section 108(a) pollutants, and VOC therefore fall within the CAA 
108(a) exclusion. Accordingly, promulgation of NSPS for VOC does not 
trigger the application of CAA section 111(d).
---------------------------------------------------------------------------

    While States are authorized to establish standards of performance 
for designated facilities, there is a fundamental obligation under CAA 
section 111(d) that such standards of performance reflect the degree of 
emission limitation achievable through the application of the BSER, as 
determined by the Administrator. This obligation derives from the 
definition of ``standard of performance'' under CAA section 111(a)(1), 
which makes no distinction between new-source and existing-source 
standards. The EPA identifies the degree of emission limitation 
achievable through application of the BSER as part of its EG. See 40 
CFR 60.22a(b)(5). While standards of performance must generally reflect 
the degree of emission limitation achievable through application of the 
BSER, CAA section 111(d)(1) also requires that the EPA regulations 
permit the States, in applying a standard of performance to a 
particular source, to take into account the source's remaining useful 
life and other factors.
    After the EPA issues final EG per the requirements under CAA 
section 111(d) and 40 CFR part 60, subpart Ba, States are required to 
submit plans that establish standards of performance for the designated 
facilities as defined in the EPA's guidelines and that contain other 
measures to implement and enforce those standards. The EPA's final EG 
issued under CAA section 111(d) do not impose binding requirements 
directly on sources, but instead provide requirements for States in 
developing their plans and criteria for assisting the EPA when judging 
the adequacy of such plans. Under CAA section 111(d), and the EPA's 
implementing regulations, a State must submit its plan to the EPA for 
approval, the EPA will evaluate the plan for completeness in accordance 
with enumerated criteria, and then will act on that plan via a 
rulemaking process to either approve or disapprove the plan in whole or 
in part. If a State does not submit a plan, or if the EPA does not 
approve a State's plan because it is not ``satisfactory,'' then the EPA 
must establish a Federal plan for that State.\97\ If EPA approves a 
State's plan, the provisions in the state plan become federally 
enforceable against the designated facility responsible for compliance 
in the same manner as the provisions of an approved State 
implementation plan under CAA section 110. If no designated facility is 
located within a State, the State must submit to the EPA a letter 
certifying to that effect in lieu of submitting a State plan. See 40 
CFR 60.23a(b).
---------------------------------------------------------------------------

    \97\ CAA section 111(d)(2)(A).
---------------------------------------------------------------------------

    Designated facilities located in Indian country would not be 
addressed by a State's CAA section 111(d) plan. Instead, an eligible 
Tribe that has one or more designated facilities located in its area of 
Indian country \98\ would have the opportunity, but not the obligation, 
to seek authority and submit a plan that establishes standards of 
performance for those facilities on its Tribal lands.\99\ If a Tribe 
does not submit a plan, or if the EPA does not approve a Tribe's plan, 
then the EPA has the authority to establish a Federal plan for that 
Tribe.\100\
---------------------------------------------------------------------------

    \98\ The EPA is aware of many oil and natural gas operations 
located in Indian Country.
    \99\ See 40 CFR part 49, subpart A.
    \100\ CAA section 111(d)(2)(A).
---------------------------------------------------------------------------

B. What is the regulatory history and litigation background of NSPS and 
EG 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.\101\ 
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).
---------------------------------------------------------------------------

    \101\ 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).

[[Page 63135]]

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 
Crude Oil and Natural Gas 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 additional 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 Amendments
    In 2012, pursuant to its duty under CAA section 111(b)(1)(B) to 
review and, if appropriate, revise the 1985 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''). The 2012 
rule updated the SO2 standards for sweetening units and the 
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, certain natural gas operated 
pneumatic controllers in the production and processing segments of the 
industry, and storage vessels in the production, processing, and 
transmission and storage segments.
    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. As 
explained below, all litigation related to NSPS OOOO is currently in 
abeyance.
4. 2016 NSPS OOOOa Rule and Related Amendments
    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 Rule'' or ``2016 NSPS 
OOOOa'').102 103 The 2016 NSPS OOOOa rule established NSPS 
for sources of GHGs and VOC emissions for certain equipment, processes, 
and operations across the Oil and Natural Gas Industry, including in 
the transmission and storage segment. 81 FR at 35832. The EPA explained 
that the 1979 listing identified the source category broadly enough to 
include that segment and, in the alternative, if the listing had 
limited the source category to the production and processing segments, 
the EPA affirmatively expanded the source category to include the 
transmission and storage segment on grounds that operations in those 
segments are a sequence of functions that are interrelated and 
necessary for getting the recovered gas ready for distribution. 81 FR 
at 35832. In addition, because this rule was the first time that the 
EPA had promulgated NSPS for GHG emissions from the Crude Oil and 
Natural Gas source category, the EPA predicated those NSPS on a 
determination that it had a rational basis to regulate GHG emissions 
from the source category. 81 FR at 35843. In response to comments, the 
EPA explained that it was not required to make an additional pollutant-
specific finding that GHG emissions from the source category contribute 
significantly to dangerous air pollution, but in the alternative, the 
EPA did make such a finding, relying on the same information that it 
relied on when determining that it had a rational basis to promulgate a 
GHGs NSPS. 81 FR at 35843.
---------------------------------------------------------------------------

    \102\ The June 3, 2016, rulemaking also included certain final 
amendments to 40 CFR part 60, subpart OOOO, to address issues on 
which the EPA had granted reconsideration.
    \103\ The EPA review which resulted in the 2016 NSPS OOOOa rule 
was instigated by a series of directives from then-President Obama 
targeted at reducing GHGs, 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 goal to address, propose and set 
standards for methane and ozone-forming emissions from new and 
modified sources in the sector (January 2015, https://obamawhitehouse.archives.gov/the-press-office/2015/01/14/fact-sheet-Administration-takes-steps-forward-climate-action-plan-anno-1).
---------------------------------------------------------------------------

    Specifically, the 2016 NSPS OOOOa addresses the following emission 
sources:
     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, 
of which the 2012 NSPS OOOO regulated emissions of VOC from only a 
subset (pneumatic controllers, centrifugal compressors, and 
reciprocating compressors, with the exception of those compressors 
located at well sites).
    On March 12, 2018 (83 FR 10628), the EPA finalized amendments to 
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.
    Petitions for judicial review and to reconsider. Following 
promulgation of the 2016 NSPS OOOOa rule, several states and industry 
associations challenged the rule in the D.C. Circuit. The Administrator 
also received five petitions for reconsideration of several provisions 
of the final rule. Copies of the petitions are posted in Docket ID No. 
EPA-HQ-OAR-2010-0505.\104\ As noted below, the EPA granted 
reconsideration as to several issues raised with respect to the 2016 
NSPS OOOOa rule and finalized certain modifications discussed in the 
next section. As explained below, all litigation challenging the 2016 
NSPS OOOOa rule is currently stayed.
---------------------------------------------------------------------------

    \104\ 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.
---------------------------------------------------------------------------

5. 2020 Policy and Technical Rules
    Regulatory action. In September 2020, the EPA published two final 
rules to amend 2012 NSPS OOOO and 2016 NSPS OOOOa. The first is titled, 
``Oil

[[Page 63136]]

and Natural Gas Sector: Emission Standards for New, Reconstructed, and 
Modified Sources Review.'' 85 FR 57018 (September 14, 2020). Commonly 
referred to as the 2020 Policy Rule, it first rescinded the regulations 
applicable to the transmission and storage segment on the basis that 
the 1979 listing limited the source category to the production and 
processing segments and that the transmission and storage segment is 
not ``sufficiently related'' to the production and processing segments, 
and therefore cannot be part of the same source category. 85 FR at 
57027, 57029. In addition, the 2020 Policy Rule rescinded methane 
requirements for the industry's production and processing segments on 
two separate bases. The first was that such standards are redundant to 
VOC standards for these segments. 85 FR at 57030. The second was that 
the rule interpreted section 111 to require, or at least authorize the 
Administrator to require, a pollutant-specific ``significant 
contribution finding'' (SCF) as a prerequisite to a NSPS for a 
pollutant, and to require that such finding be supported by some 
identified standard or established set of criteria for determining 
which contributions are ``significant.'' 85 FR at 57034. The rule went 
on to conclude that the alternative significant-contribution finding 
that the EPA made in the 2016 Rule for GHG emissions was flawed because 
it accounted for emissions from the transmission and storage segment 
and because it was not supported by criteria or a threshold. 85 FR at 
57038.\105\
---------------------------------------------------------------------------

    \105\ Following the promulgation of the 2020 Policy Rule, the 
EPA promulgated a final rule that identified a standard or criteria 
for determining which contributions are ``significant,'' which the 
D.C. Circuit vacated. ``Pollutant-Specific Significant Contribution 
Finding for Greenhouse Gas Emissions From New, Modified, and 
Reconstructed Stationary Sources: Electric Utility Generating Units, 
and Process for Determining Significance of Other New Source 
Performance Standards Source Categories.'' 86 FR 2542 (Jan. 13, 
2021), vacated by California v. EPA, No. 21-1035 (D.C. Cir.) (Order, 
April 5, 2021, Doc. #1893155).
---------------------------------------------------------------------------

    Published on September 15, 2020, the second of the two rules is 
titled, ``Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources Reconsideration.'' Commonly 
referred to as the 2020 Technical Rule, this second rule made further 
amendments to the 2016 NSPS OOOOa following the 2020 Policy Rule to 
eliminate or reduce certain monitoring obligations and to address a 
range of issues in response to administrative petitions for 
reconsideration and other technical and implementation issues brought 
to the EPA's attention since the 2016 NSPS OOOOa rulemaking. 
Specifically, the 2020 Technical Rule exempted low-production well 
sites from fugitives monitoring (previously required semiannually), 
required semiannual monitoring at gathering and boosting compressor 
stations (previously quarterly), streamlined recordkeeping and 
reporting requirements, allowed compliance with certain equivalent 
State requirements as an alternative to NSPS fugitive requirements, 
streamlined the application process to request the use of new 
technologies to monitor for fugitive emissions, addressed storage tank 
batteries for applicability determination purposes and finalized 
several technical corrections. Because the 2020 Technical Rule was 
issued the day after the EPA's rescission of methane regulations in the 
2020 Policy Rule, the amendments made in the 2020 Technical Rule 
applied only to the requirements to regulate VOC emissions from this 
source category. The 2020 Policy Rule amended 40 CFR part 60, subparts 
OOOO and OOOOa, as finalized in 2016. The 2020 Technical Rule amended 
the 40 CFR part 60, subpart OOOOa, as amended by the 2020 Policy Rule.
    Petitions to reconsider. The EPA received three petitions for 
reconsideration of the 2020 rulemakings. Two of the petitions sought 
reconsideration of the 2020 Policy Rule. As discussed below, on June 
30, 2021, the President signed into law S.J. Res. 14, a joint 
resolution under the CRA disapproving the 2020 Policy Rule, and as a 
result, the petitions for reconsideration on the 2020 Policy Rule are 
now moot. All three petitions sought reconsideration of certain 
elements of the 2020 Technical Rule.
    Litigation. Several States and non-governmental organizations 
challenged the 2020 Policy Rule as well as the 2020 Technical Rule. All 
petitions for review regarding the 2020 Policy Rule were consolidated 
into one case in the D.C. Circuit. State of California, et al. v. EPA, 
No. 20-1357. On August 25, 2021, after the enactment of the joint 
resolution of Congress disapproving the 2020 Policy Rule (explained in 
section VIII below), the court granted petitioners motion to 
voluntarily dismiss their cases. Id. ECF Dkt #1911437. All petitions 
for review regarding the 2020 Technical Rule were consolidated into a 
different case in the D.C. Circuit. Environmental Defense Fund, et al. 
v. EPA, No. 20-1360 (D.C. Cir.). On February 19, 2021, the court issued 
an order granting a motion by the EPA to hold in abeyance the 
consolidated litigation over the 2020 Technical Rule pending EPA's 
rulemaking actions in response to E.O. 13990 and pending the conclusion 
of EPA's potential reconsideration of the 2020 Technical Rule. Id. ECF 
Dkt #1886335.
    As mentioned above, the EPA received petitions for judicial review 
regarding the 2012, 2013, and 2014 NSPS OOOO rules as well as the 2016 
NSPS OOOOa rule. The challenges to the 2012 NSPS OOOO rule (as amended 
by the 2013 NSPS OOOO and 2014 NSPS OOOO rules) were consolidated. 
American Petroleum Institute v. EPA, No. 13-1108 (D.C. Cir.). The 
majority of those cases were further consolidated with the consolidated 
challenges to the 2016 NSPS OOOOa rule. West Virginia v. EPA, No. 16-
1264 (D.C. Cir.), see specifically ECF Dkt #1654072. As such, West 
Virginia v. EPA includes challenges to the 2012 NSPS OOOO rule (as 
amended by the 2013 NSPS OOOO and 2014 NSPS OOOO rules) as well as 
challenges to the 2016 NSPS OOOOa rule.\106\ On December 10, 2020, the 
court granted a joint motion of the parties in West Virginia v. EPA to 
hold that case in abeyance until after the mandate has issued in the 
case regarding challenges to the 2020 Technical Rule. West Virginia v. 
EPA, ECF Dkt #1875192.
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    \106\ When the EPA issued the 2016 NSPS OOOOa rule, a challenge 
to the 2012 NSPS OOOO rule for failing to regulate methane was 
severed and assigned to a separate case, NRDC v. EPA, No. 16-1425 
(D.C. Cir.), pending judicial review of the 2016 NSPS OOOOa in 
American Petroleum Institute v. EPA, No. 13-1108 (D.C. Cir.).
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C. Congressional Review Act (CRA) Joint Resolution of Disapproval

    On June 30, 2021, the President signed into law a joint resolution 
of Congress, S.J. Res. 14, adopted under the CRA,\107\ disapproving the 
2020 Policy Rule.\108\ By the terms of the CRA, the signing into law of 
the CRA joint resolution of disapproval means that the 2020 Policy Rule 
is ``treated as though [it] had never taken effect.'' 5 U.S.C. 801(f). 
As a result, the VOC and methane standards for the transmission and 
storage segment, as well as the methane standards for the production 
and processing segments--all of which had been rescinded in the 2020 
Policy Rule--remain in effect. In addition, the EPA's authority and 
obligation to require the States to regulate existing sources of 
methane in the Crude Oil and

[[Page 63137]]

Natural Gas source category under section 111(d) of the CAA also 
remains in effect.
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    \107\ The Congressional Review Act was adopted in Subtitle E of 
the Small Business Regulatory Enforcement Fairness Act of 1996.
    \108\ ``Oil and Natural Gas Sector: Emission Standards for New, 
Reconstructed, and Modified Sources Review,'' 85 FR 57018 (Sept. 14, 
2020) (``2020 Policy Rule'').
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    The CRA resolution did not address the 2020 Technical Rule; 
therefore, those amendments remain in effect with respect to the VOC 
standards for the production and processing segments in effect at the 
time of its enactment. As part of this rulemaking, in sections VIII and 
X the EPA discusses the impact of the CRA resolution, and identifies 
and proposes appropriate changes to reinstate the regulatory text that 
had been rescinded by the 2020 Policy Rule and to resolve any 
discrepancies in the regulatory text between the 2016 NSPS OOOOa Rule 
and 2020 Technical Rule.

V. Related Emissions Reduction Efforts

    This section summarizes related State actions and other Federal 
actions regulating oil and natural gas emissions sources and summarizes 
industry and voluntary efforts to reduce climate change. The proposed 
NSPS OOOOb and EG OOOOc include specific measures that build on the 
experience and knowledge the Agency and industry have gained through 
voluntary programs, as well as the leadership of the States in 
pioneering new regulatory programs. The proposed NSPS OOOOb and EG 
OOOOc consists of reasonable, proven, cost-effective technologies and 
practices that reflect the evolutionary nature of the Oil and Natural 
Gas Industry and proactive regulatory and voluntary efforts. The EPA 
intends that the requirements proposed in this document will spur all 
industry stakeholders in all parts of the country to apply these 
readily available and cost-effective measures.

A. Related State Actions and Other Federal Actions Regulating Oil and 
Natural Gas Sources

    The EPA recognizes that several States and other Federal agencies 
currently regulate the Oil and Natural Gas Industry. The EPA also 
recognizes that these State and other Federal agency regulatory 
programs have matured since the EPA began implementing its 2012 NSPS 
and subsequent 2016 NSPS. The EPA further acknowledges the technical 
innovations that the Oil and Natural Gas Industry has made during the 
past decade; this industry is fast-paced and constantly changing based 
on the latest technology. The EPA commends these efforts and recognizes 
States for their innovative standards, alternative compliance options, 
and implementation strategies. The EPA recognizes that any one effort 
will not be enough to address the increasingly dangerous impacts of 
climate change on public health and welfare and believes that 
consistent Federal regulation of the Crude Oil and Natural Gas source 
category plays an important role. To have a meaningful impact on 
climate change and its impact to human health and the environment, a 
multifaceted approach needs to be taken to ensure methane reductions 
will be realized. The EPA also recognizes that States and other Federal 
agencies regulate in accordance with their own authorities and within 
their own respective jurisdictions, and collectively do not fully 
address the range of sources and emission reduction measures contained 
in this proposal. Direct Federal regulation of methane from new sources 
combined with the approved State plans that are consistent with the 
EPA's EG for existing sources will bring national consistency to level 
the regulatory playing field, help promote technological innovation, 
and reduce both climate- and other health-harming pollution from a 
large number of sources that are either currently unregulated or where 
additional cost-effective reductions can be obtained. The EPA is 
committed to working within its authority to provide opportunities to 
align its programs with other existing State and Federal programs to 
reduce unnecessary regulatory redundancy where appropriate.
    Among assessing various studies and emissions data, the EPA 
reviewed many current and proposed State regulatory programs to 
identify potential regulatory options that could be considered for 
BSER.\109\ For example, the EPA reviewed California, Colorado, and 
Canadian regulations, as well as a pending proposed rule in New Mexico, 
that require non-emitting pneumatic devices at certain facilities and 
in certain circumstances. The EPA also examined California, Colorado, 
New Mexico (proposed), Pennsylvania, Wyoming, and the Bureau of Land 
Management (BLM) standards for liquids unloading events. Some of these 
States have led the way in regulating emissions sources that were not 
yet subject to requirements under the NSPS OOOOa. For example, Colorado 
requires the use of best management practices to minimize hydrocarbon 
emissions and the need for well venting associated with downhole well 
maintenance and liquids unloading, unless venting is necessary for 
safety. Other States, such as New Mexico, are evaluating similar 
requirements. Other States have requirements for emission sources 
currently regulated under NSPS OOOOa that are more stringent. For 
example, California and Colorado require continuous bleed natural gas-
driven pneumatic controllers be non-emitting, with specified 
exceptions. We recognize that, in some cases, the EPA's proposed NSPS 
and/or EG may be more stringent than existing programs and, in other 
cases, may be less stringent than existing programs. After careful 
review and consideration of State regulatory programs in place and 
proposed State regulations, we are proposing NSPS and EG that, when 
implemented, will reduce emissions of harmful air pollutants, promote 
gas capture and beneficial use, and provide opportunity for flexibility 
and expanded transparency in order to yield a consistent and 
accountable national program that provides a clear path for States and 
other Federal agencies to further partner to ensure their programs work 
in conjunction with each other.
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    \109\ The NSPS OOOOb and EG TSD provides a high-level summary of 
the state programs that the agency assessed for purposes of this 
proposal.
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    As an example of how the EPA strives to work with sources in States 
that have overlapping regulations for the Oil and Natural Gas Industry, 
the 2020 Technical Rule included approval of certain State programs as 
alternatives to certain requirements in the Federal NSPS. Subject to 
certain caveats, the EPA deemed certain fugitive emissions standards 
for well sites and compressor stations located in specific States 
equivalent to the NSPS in an effort to reduce any regulatory burden 
imposed by duplicative State and Federal regulations. See 40 CFR 
60.5399a. The EPA worked extensively with States and reviewed many 
details of many State programs in this effort. Further, the 2020 
Technical Rule amended 40 CFR part 60, subpart OOOOa, to incorporate a 
process that allows other States not already listed in 40 CFR 60.5399a 
to request approval of their fugitive monitoring program as an 
alternative to the NSPS. The EPA is proposing to include a similar 
request and approval process in NSPS OOOOb. Further, the EPA plans to 
work closely with States as they develop their State plans pursuant to 
the EG to look for opportunities to reduce unnecessary administrative 
burden imposed by redundant and duplicative regulatory requirements and 
help States that want to establish more stringent standards.
    In addition to States, certain Federal agencies also regulate 
aspects of the oil and natural gas industry pursuant to their own 
authorities and have other established programs affecting the industry. 
The EPA believes that Federal regulatory actions and efforts will 
provide other environmental co-

[[Page 63138]]

benefits, but the EPA recognizes itself to be the Federal agency that 
has primary responsibility to protect human health and the environment 
and has been given the unique responsibility and authority by Congress 
to address the suite of harmful air pollutants associated with this 
source category. The EPA further believes that to have a meaningful 
impact to address the dangers of climate change, it is going to require 
an ``all hands-on deck'' effort across all States and all Federal 
agencies. The EPA has maintained an ongoing dialogue with its Federal 
partners during the development of this proposed rule to minimize any 
potential regulatory conflicts and to minimize confusion and regulatory 
burden on the part of owners and operators. The below description 
summarizes other agencies' regulations and other established Federal 
programs.
    The U.S. Department of the Interior (DOI) regulates the extraction 
of oil and gas from Federal lands. Bureaus within the DOI include BLM 
and the Bureau of Ocean Energy Management (BOEM). The BLM manages the 
Federal Government's onshore subsurface mineral estate--about 700 
million acres (30 percent of the U.S.)--for the benefit of the American 
public. The BLM maintains an oil and gas leasing program pursuant to 
the Mineral Leasing Act, the Mineral Leasing Act for Acquired Lands, 
the Federal Land Management and Policy Act, and the Federal Oil and Gas 
Royalty Management Act. Pursuant to a delegation of Secretarial 
authority, the BLM also oversees oil and gas operations on many Indian/
Tribal leases. The BLM's oil and gas operating regulations are found in 
43 CFR part 3160. An oil and gas operator's general environmental and 
safety obligations are found at 43 CFR 3162.5. The BLM does not 
directly regulate emissions for the purposes of air quality. However, 
BLM does regulate venting and flaring of natural gas for the purposes 
of preventing waste. The governing Resource Management Plan may require 
lessees to follow State and the EPA emissions regulations. An operator 
may be required to control/mitigate emissions as a condition of 
approval (COA) on a drilling permit. The need for such a COA is 
determined by the environmental review process. The BLM's rules 
governing the venting and flaring of gas are contained in NTL-4A, which 
was issued in 1980. Under NTL-4A, limitations on royalty-free venting 
and flaring constitute the primary mechanism for addressing the surface 
waste of gas. In 2016, the BLM replaced NTL-4A with a new rule 
governing venting and flaring (``Waste Prevention Rule''). In addition 
to restricting royalty-free flaring, the rule set emissions standards 
for tanks and pneumatic equipment and established LDAR requirements. In 
2020, a U.S. District Court of Wyoming largely vacated that rule, 
thereby reinstating NTL-4A. More detailed information can be found at 
the BLM's website: https://www.blm.gov/programs/energy-and-minerals/oil-and-gas/operations-and-production/methane-and-waste-prevention-rule.
    The BOEM manages the development of U.S. Outer Continental Shelf 
(offshore) energy and mineral resources. BOEM has air quality 
jurisdiction in the Gulf of Mexico \110\ and the North Slope Borough of 
Alaska.\111\ BOEM also has air jurisdiction in Federal waters on the 
Outer Continental Shelf 3-9 miles offshore (depending on State) and 
beyond. The Outer Continental Shelf Lands Act (OCSLA) section 5(a)(8) 
states, ``The Secretary of the Interior is authorized to prescribe 
regulations `for compliance with the national ambient air quality 
standards pursuant to the CAA . . . to the extent that activities 
authorized under [the Outer Continental Shelf Lands Act] significantly 
affect the air quality of any State.' '' The EPA and States have the 
air jurisdiction onshore and in State waters, and the EPA has air 
jurisdiction offshore in certain areas. More detailed information can 
be found at BOEM's website: https://www.boem.gov/.
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    \110\ The CAA gave BOEM air jurisdiction west of 87.5[deg] 
longitude in the Gulf of Mexico region.
    \111\ The Consolidated Appropriations Act of 2012 gave BOEM air 
jurisdiction in the North Slope Borough of Alaska.
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    The U.S. Department of Transportation (DOT) manages the U.S. 
transportation system. Within DOT, the Pipeline and Hazardous Materials 
Safety Administration (PHMSA) is responsible for regulating and 
ensuring the safe and secure transport of energy and other hazardous 
materials to industry and consumers by all modes of transportation, 
including pipelines. While PHMSA regulatory requirements for gas 
pipeline facilities have focused on human safety, which has attendant 
environmental co-benefits, the ``Protecting our Infrastructure of 
Pipelines and Enhancing Safety Act of 2020'' (Pub. L. 116-260, Division 
R; ``PIPES Act of 2020''), which was signed into law on December 27, 
2020, revised PHMSA organic statutes to emphasize the centrality of 
environmental safety and protection of the environment in PHMSA 
decision making. 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.\112\ In addition, the PIPES Act of 2020 contains 
several provisions that specifically address the minimization of 
releases of natural gas from pipeline facilities, such as a mandate 
that the Secretary of Transportation promulgate regulations related to 
gas pipeline LDAR programs. More detailed information can be found at 
PHMSA's website: https://www.phmsa.dot.gov/.
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    \112\ 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.
---------------------------------------------------------------------------

    The U.S. Department of Energy (DOE) develops oil and natural gas 
policies and funds research on advanced fuels and monitoring and 
measurement technologies. Specifically, the Advanced Research Projects 
Agency-Energy (ARPA-E) program advances high-potential, high-impact 
energy technologies that are too early for private-sector investment. 
APRA-E awardees are unique because they are developing entirely new 
technologies. More detailed information can be found at ARPA-E's 
website: https://arpa-e.energy.gov/. Also, the U.S. Energy Information 
Administration (EIA) compiles data on energy consumption, prices, 
including natural gas, and coal. More detailed information can be found 
at the EIA's website: https://www.eia.gov/.
    The U.S. Federal Energy Regulatory Commission (FERC) is an 
independent agency that regulates the interstate transmission of 
electricity, natural gas,\113\ and oil.\114\ FERC also reviews 
proposals to build liquefied natural gas terminals and interstate 
natural gas pipelines as well as licensing hydropower projects. The 
Commission's responsibilities for the crude oil industry include the 
following: Regulation of rates and practices of oil pipeline companies 
engaged in interstate transportation; establishment of equal service 
conditions to provide shippers with equal access to pipeline 
transportation; and establishment of reasonable rates for transporting 
petroleum and petroleum products by pipeline. The Commission's 
responsibilities for the natural gas industry include the following: 
Regulation of pipeline, storage, and

[[Page 63139]]

liquefied natural gas facility construction; regulation of natural gas 
transportation in interstate commerce; issuance of certificates of 
public convenience and necessity to prospective companies providing 
energy services or constructing and operating interstate pipelines and 
storage facilities; regulation of facility abandonment, establishment 
of rates for services; regulation of the transportation of natural gas 
as authorized by the Natural Gas Policy Act and OCSLA; and oversight of 
the construction and operation of pipeline facilities at U.S. points of 
entry for the import or export of natural gas. FERC has no jurisdiction 
over construction or maintenance of production wells, oil pipelines, 
refineries, or storage facilities. More detailed information can be 
found at FERC's website: https://www.ferc.gov/.
---------------------------------------------------------------------------

    \113\ https://www.ferc.gov/industries-data/natural-gas.
    \114\ https://www.ferc.gov/industries-data/oil.
---------------------------------------------------------------------------

B. Industry and Voluntary Actions To Address Climate Change

    Separate from regulatory requirements, some owners or operators of 
facilities in the Oil and Natural Gas Industry choose to participate in 
voluntary initiatives. Specifically, over 100 oil and natural gas 
companies participate in the EPA Natural Gas STAR and Methane Challenge 
partnership programs. Owners or operators also participate in a growing 
number of voluntary programs unaffiliated with the EPA voluntary 
programs. The EPA is aware of at least 19 such initiatives.\115\ Firms 
might participate in voluntary environmental programs for a variety of 
reasons, including attracting customers, employees, and investors who 
value more environmental-responsible goods and services; finding 
approaches to improve efficiency and reduce costs; and preparing for or 
helping inform future regulations.\116\ \117\
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    \115\ Highwood Emissions Management (2021). ``Voluntary 
Emissions Reduction Initiatives for Responsibly Sourced Oil and 
Gas.'' Available for download at: https://highwoodemissions.com/research/.
    \116\ Borck, J.C. and C. Coglianese (2009). ``Voluntary 
Environmental Programs: Assessing Their Effectiveness.'' Annual 
Review of Environment and Resources 34(1): 305-324.
    \117\ Brouhle, K., C. Griffiths, and A. Wolverton. (2009). 
``Evaluating the role of EPA policy levers: An examination of a 
voluntary program and regulatory threat in the metal-finishing 
industry.'' Journal of Environmental Economics and Management. 
57(2): 166-181.
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    The EPA's Natural Gas STAR Program started in 1993 and seeks to 
achieve methane emission reductions through implementation of cost-
effective best practices and technologies. Partner companies document 
their voluntary emission reduction activities and can report their 
accomplishments to the EPA annually. Natural Gas STAR includes over 90 
partners across the natural gas value chain. Through 2019 partner 
companies report having eliminated nearly 1.7 trillion cubic feet of 
methane emissions since 1993.
    The EPA's Methane Challenge Program was launched in 2016 and 
expands on the Natural Gas STAR Program with ambitious, quantifiable 
commitments and detailed, transparent reporting and partner 
recognition. Annually Methane Challenge partners submit facility-level 
reports that characterize the methane emission sources at their 
facilities and detail voluntary actions taken to reduce methane 
emissions. The EPA emphasizes the importance of transparency with the 
publication of these facility-level data. Although this program 
includes nearly 70 companies from all segments of the industry, most 
partners operate in the transmission and distribution segments.
    Other voluntary programs for the oil and natural gas industry are 
administered by diverse organizations, including trade associations and 
non-profits. While the field of voluntary initiatives continues to 
grow, it is difficult to understand the present, and potential future, 
impact these initiatives will have on reducing methane emissions as the 
majority of these initiatives publish aggregated program-level data. 
The EPA recognizes the voluntary efforts of industry in reducing 
methane emissions beyond what is required by current regulations and in 
significantly expanding the understanding of methane mitigation 
measures. While progress has been made, there is still considerable 
remaining need to further reduce methane emissions from the Industry.

VI. Environmental Justice Considerations, Implications, and Stakeholder 
Outreach

    To better inform this proposed rulemaking, the EPA assessed the 
characteristics of populations living near sources affected by the rule 
and conducted extensive outreach to overburdened and underserved 
communities and to environmental justice organizations. During our 
engagement with communities, concerns were raised regarding health 
effects of air pollutants, implications of climate change on lifestyle 
changes, water quality, or extreme heat events, and accessibility to 
data and information regarding sources near their homes. The EPA then 
considered this input along with other stakeholder input in designing 
the proposed rule. For example, one key issue identified through 
stakeholder input is the use of cutting-edge technologies for methane 
detection that can allow for rapid detection of high-emitting sources. 
As described below, the EPA is proposing to allow the use of such 
technologies in this rule, alongside a rigorous fugitive emissions 
monitoring program that is based on traditional OGI technology. Another 
key concern the Agency heard is addressing large emission sources 
faster, which, in addition to seeking more information on new detection 
technologies, the EPA is proposing to address with more frequent 
monitoring at sites with more emissions. The EPA also heard that 
adjacent communities are concerned about health impacts, and the EPA is 
proposing rigorous guidelines for pollution sources at existing 
facilities, methane standards for storage vessels, strengthened and 
expanded standards for pneumatic controllers, and standards for liquids 
unloading events that will further reduce emissions of those 
pollutants. These are just a few examples of how this proposed rule 
provides benefits to communities; section XII provides a full 
explanation and rationale of the proposed actions.
    E.O. 12898 directs the EPA to identify the populations of concern 
who are most likely to experience unequal burdens from environmental 
harms; specifically, minority populations, low-income populations, and 
indigenous peoples. 59 FR 7629 (February 16, 1994). Additionally, E.O. 
13985 was signed in 2021 to advance racial equity and support 
underserved communities--including people of color and others who have 
been historically underserved, marginalized, and adversely affected by 
persistent poverty and inequality--through Federal Government actions. 
86 FR 7009 (January 20, 2021). With respect to climate change, E.O. 
14008, titled ``Tackling Climate Change at Home and Abroad,'' was 
signed on January 27, 2021, stating that climate considerations shall 
be an essential element of United States foreign policy and national 
security, working in partnership with foreign governments, States, 
territories, and local governments, and communities potentially 
impacted by climate change. The EPA defines environmental justice (EJ) 
as the fair treatment and meaningful involvement of all people 
regardless of race, color, national origin, or income with respect to 
the development, implementation, and enforcement of environmental laws, 
regulations, and policies. The EPA further defines the term fair 
treatment to

[[Page 63140]]

mean that ``no group of people should bear a disproportionate burden of 
environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies'' (https://www.epa.gov/environmentaljustice). In recognizing that minority and low-income 
populations often bear an unequal burden of environmental harms and 
risks, the EPA continues to consider ways of protecting them from 
adverse public health and environmental effects of air pollution 
emitted from sources within the Oil and Natural Gas Industry that are 
addressed in this proposed rulemaking.

A. Environmental Justice and the Impacts of Climate Change

    In 2009, under the Endangerment and Cause or Contribute Findings 
for Greenhouse Gases Under Section 202(a) of the Clean Air Act 
(``Endangerment Finding'', 74 FR 66496), the Administrator considered 
how climate change threatens the health and welfare of the U.S. 
population.\118\ As part of that consideration, she also considered 
risks to minority and low-income individuals and communities, finding 
that certain parts of the U.S. population may be especially vulnerable 
based on their characteristics or circumstances. These groups include 
economically and socially disadvantaged communities, including those 
that have been historically marginalized or overburdened; individuals 
at vulnerable lifestages, such as the elderly, the very young, and 
pregnant or nursing women; those already in poor health or with 
comorbidities; the disabled; those experiencing homelessness, mental 
illness, or substance abuse; and/or Indigenous or minority populations 
dependent on one or limited resources for subsistence due to factors 
including but not limited to geography, access, and mobility.
---------------------------------------------------------------------------

    \118\ Earlier studies and reports can be found at https://www.epa.gov/cira/social-vulnerability-report.
---------------------------------------------------------------------------

    Scientific assessment reports produced over the past decade by the 
USGCRP,\119\ \120\ the IPCC,\121\ \122\ \123\ \124\ the National 
Academies of Science, Engineering, and Medicine,\125\ \126\ and the EPA 
\127\ add more evidence that the impacts of climate change raise 
potential EJ concerns. These reports conclude that less-affluent, 
traditionally marginalized and predominantly non-White communities can 
be especially vulnerable to climate change impacts because they tend to 
have limited resources for adaptation, are more dependent on climate-
sensitive resources such as local water and food supplies, or have less 
access to social and information resources. Some communities of color, 
specifically populations defined jointly by ethnic/racial 
characteristics and geographic location (e.g., African-American, Black, 
and Hispanic/Latino communities; Native Americans, particularly those 
living on Tribal lands and Alaska Natives), may be uniquely vulnerable 
to climate change health impacts in the U.S., as discussed below. In 
particular, the 2016 scientific assessment on the Impacts of Climate 
Change on Human Health \128\ found with high confidence that 
vulnerabilities are place- and time-specific, lifestages and ages are 
linked to immediate and future health impacts, and social determinants 
of health are linked to greater extent and severity of climate change-
related health impacts.
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    \119\ USGCRP, 2018: Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, 1515 pp. doi: 10.7930/NCA4.2018.
    \120\ USGCRP, 2016: The Impacts of Climate Change on Human 
Health in the United States: A Scientific Assessment. Crimmins, A., 
J. Balbus, J.L. Gamble, C.B. Beard, J.E. Bell, D. Dodgen, R.J. 
Eisen, N. Fann, M.D. Hawkins, S.C. Herring, L. Jantarasami, D.M. 
Mills, S. Saha, M.C. Sarofim, J. Trtanj, and L. Ziska, Eds. U.S. 
Global Change Research Program, Washington, DC, 312 pp. http://dx.doi.org/10.7930/J0R49NQX.
    \121\ Oppenheimer, M., M. Campos, R. Warren, J. Birkmann, G. 
Luber, B. O'Neill, and K. Takahashi, 2014: Emergent risks and key 
vulnerabilities. In: Climate Change 2014: Impacts, Adaptation, and 
Vulnerability. Part A: Global and Sectoral Aspects. Contribution of 
Working Group II to the Fifth Assessment Report of the 
Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, 
D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, 
K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. 
Levy, S. MacCracken, P.R. Mastrandrea, and L.L. White (eds.)]. 
Cambridge University Press, Cambridge, United Kingdom and New York, 
NY, USA, pp. 1039-1099.
    \122\ Porter, J.R., L. Xie, A.J. Challinor, K. Cochrane, S.M. 
Howden, M.M. Iqbal, D.B. Lobell, and M.I. Travasso, 2014: Food 
security and food production systems. In: Climate Change 2014: 
Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral 
Aspects. Contribution of Working Group II to the Fifth Assessment 
Report of the Intergovernmental Panel on Climate Change [Field, 
C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. 
Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, 
E.S. Kissel, A.N. Levy, S. MacCracken, P.R. Mastrandrea, and L.L. 
White (eds.)]. Cambridge University Press, Cambridge, United Kingdom 
and New York, NY, USA, pp. 485-533.
    \123\ Smith, K.R., A. Woodward, D. Campbell-Lendrum, D.D. 
Chadee, Y. Honda, Q. Liu, J.M. Olwoch, B. Revich, and R. Sauerborn, 
2014: Human health: impacts, adaptation, and co-benefits. In: 
Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: 
Global and Sectoral Aspects. Contribution of Working Group II to the 
Fifth Assessment Report of the Intergovernmental Panel on Climate 
Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. 
Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. 
Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken, P.R. 
Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, 
Cambridge, United Kingdom and New York, NY, USA, pp. 709-754.
    \124\ IPCC, 2018: Global Warming of 1.5 [deg]C. An IPCC Special 
Report on the impacts of global warming of 1.5 [deg]C above pre-
industrial levels and related global greenhouse gas emission 
pathways, in the context of strengthening the global response to the 
threat of climate change, sustainable development, and efforts to 
eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. P[ouml]rtner, 
D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. 
P[eacute]an, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. 
Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. 
Waterfield (eds.)]. In Press.
    \125\ National Research Council. 2011. America's Climate 
Choices. Washington, DC: The National Academies Press. https://doi.org/10.17226/12781.
    \126\ National Academies of Sciences, Engineering, and Medicine. 
2017. Communities in Action: Pathways to Health Equity. Washington, 
DC: The National Academies Press. https://doi.org/10.17226/24624.
    \127\ EPA. 2021. Climate Change and Social Vulnerability in the 
United States: A Focus on Six Impacts. U.S. Environmental Protection 
Agency, EPA 430-R-21-003.
    \128\ USGCRP, 2016: The Impacts of Climate Change on Human 
Health in the United States: A Scientific Assessment.
---------------------------------------------------------------------------

    Per the NCA4, ``Climate change affects human health by altering 
exposures to heat waves, floods, droughts, and other extreme events; 
vector-, food- and waterborne infectious diseases; changes in the 
quality and safety of air, food, and water; and stresses to mental 
health and well-being.'' \129\ Many health conditions such as 
cardiopulmonary or respiratory illness and other health impacts are 
associated with and exacerbated by an increase in GHGs and climate 
change outcomes, which is problematic as these diseases occur at higher 
rates within vulnerable communities. Importantly, negative public 
health outcomes include those that are physical in nature, as well as 
mental, emotional, social, and economic.
---------------------------------------------------------------------------

    \129\ Ebi, K.L., J.M. Balbus, G. Luber, A. Bole, A. Crimmins, G. 
Glass, S. Saha, M.M. Shimamoto, J. Trtanj, and J.L. White-Newsome, 
2018: Human Health. In Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, pp. 539-571. doi: 10.7930/
NCA4.2018.CH14.
---------------------------------------------------------------------------

    The scientific assessment literature, including the aforementioned 
reports, demonstrates that there are myriad ways

[[Page 63141]]

in which these populations may be affected at the individual and 
community levels. Outdoor workers, such as construction or utility 
workers and agricultural laborers, who are frequently part of already 
at-risk groups, are exposed to poor air quality and extreme 
temperatures without relief. Furthermore, individuals within EJ 
populations of concern face greater housing and clean water insecurity 
and bear disproportionate economic impacts and health burdens 
associated with climate change effects. They also have less or limited 
access to healthcare and affordable, adequate health or homeowner 
insurance. The urban heat island effect can add additional stress to 
vulnerable populations in densely populated cities who do not have 
access to air conditioning.\130\ Finally, resiliency and adaptation are 
more difficult for economically disadvantaged communities: They tend to 
have less liquidity, individually and collectively, to move or to make 
the types of infrastructure or policy changes necessary to limit or 
reduce the hazards they face. They frequently face systemic, 
institutional challenges that limit their power to advocate for and 
receive resources that would otherwise aid in resiliency and hazard 
reduction and mitigation.
---------------------------------------------------------------------------

    \130\ USGCRP, 2016.
---------------------------------------------------------------------------

    The assessment literature cited in the EPA's 2009 Endangerment 
Finding, as well as Impacts of Climate Change on Human Health, also 
concluded that certain populations and people in particular stages of 
life, including children, are most vulnerable to climate-related health 
effects. The assessment literature produced from 2016 to the present 
strengthens these conclusions by providing more detailed findings 
regarding related vulnerabilities and the projected impacts youth may 
experience. These assessments--including the NCA4 (2018) and The 
Impacts of Climate Change on Human Health in the United States (2016)--
describe how children's unique physiological and developmental factors 
contribute to making them particularly vulnerable to climate change. 
Impacts to children are expected from air pollution, infectious and 
waterborne illnesses, and mental health effects resulting from extreme 
weather events. In addition, children are among those especially 
susceptible to allergens, as well as health effects associated with 
heat waves, storms, and floods. Additional health concerns may arise in 
low-income households, especially those with children, if climate 
change reduces food availability and increases prices, leading to food 
insecurity within households. More generally, these reports note that 
extreme weather and flooding can cause or exacerbate poor health 
outcomes by affecting mental health because of stress; contributing to 
or worsening existing conditions, again due to stress or also as a 
consequence of exposures to water and air pollutants; or by impacting 
hospital and emergency services operations.\131\ Further, in urban 
areas in particular, flooding can have significant economic 
consequences due to effects on infrastructure, pollutant exposures, and 
drowning dangers. The ability to withstand and recover from flooding is 
dependent in part on the social vulnerability of the affected 
population and individuals experiencing an event.\132\
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    \131\ Ebi, K.L., J.M. Balbus, G. Luber, A. Bole, A. Crimmins, G. 
Glass, S. Saha, M.M. Shimamoto, J. Trtanj, and J.L. White-Newsome, 
2018: Human Health. In Impacts, Risks, and Adaptation in the United 
States: Fourth National Climate Assessment, Volume II [Reidmiller, 
D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. 
Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research 
Program, Washington, DC, USA, pp. 539-571. doi: 10.7930/
NCA4.2018.CH14.
    \132\ National Academies of Sciences, Engineering, and Medicine 
2019. Framing the Challenge of Urban Flooding in the United States. 
Washington, DC: The National Academies Press. https://doi.org/10.17226/25381.
---------------------------------------------------------------------------

    The Impacts of Climate Change on Human Health (USGCRP, 2016) also 
found that some communities of color, low-income groups, people with 
limited English proficiency, and certain immigrant groups (especially 
those who are undocumented) live with many of the factors that 
contribute to their vulnerability to the health impacts of climate 
change. While difficult to isolate from related socioeconomic factors, 
race appears to be an important factor in vulnerability to climate-
related stress, with elevated risks for mortality from high 
temperatures reported for Black or African-American individuals 
compared to White individuals after controlling for factors such as air 
conditioning use. Moreover, people of color are disproportionately 
exposed to air pollution based on where they live, and 
disproportionately vulnerable due to higher baseline prevalence of 
underlying diseases such as asthma, so climate exacerbations of air 
pollution are expected to have disproportionate effects on these 
communities. Locations with greater health threats include urban areas 
(due to, among other factors, the ``heat island'' effect where built 
infrastructure and lack of green spaces increases local temperatures), 
areas where airborne allergens and other air pollutants already occur 
at higher levels, and communities experienced depleted water supplies 
or vulnerable energy and transportation infrastructure.
    The recent EPA report on climate change and social vulnerability 
\133\ examined four socially vulnerable groups (individuals who are low 
income, minority, without high school diplomas, and/or 65 years and 
older) and their exposure to several different climate impacts (air 
quality, coastal flooding, extreme temperatures, and inland flooding). 
This report found that Black and African-American individuals were 40% 
more likely to currently live in areas with the highest projected 
increases in mortality rates due to climate-driven changes in extreme 
temperatures, and 34% more likely to live in areas with the highest 
projected increases in childhood asthma diagnoses due to climate-driven 
changes in particulate air pollution. The report found that Hispanic 
and Latino individuals are 43% more likely to live in areas with the 
highest projected labor hour losses in weather-exposed industries due 
to climate-driven warming, and 50% more likely to live in coastal areas 
with the highest projected increases in traffic delays due to increases 
in high-tide flooding. The report found that American Indian and Alaska 
Native individuals are 48% more likely to live in areas where the 
highest percentage of land is projected to be inundated due to sea 
level rise, and 37% more likely to live in areas with high projected 
labor hour losses. Asian individuals were found to be 23% more likely 
to live in coastal areas with projected increases in traffic delays 
from high-tide flooding. Those with low income or no high school 
diploma are about 25% more likely to live in areas with high projected 
losses of labor hours, and 15% more likely to live in areas with the 
highest projected increases in asthma due to climate-driven increases 
in particulate air pollution, and in areas with high projected 
inundation due to sea level rise.
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    \133\ EPA. 2021. Climate Change and Social Vulnerability in the 
United States: A Focus on Six Impacts. U.S. Environmental Protection 
Agency, EPA 430-R-21-003.
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    Impacts of Climate Change on Indigenous Communities. Indigenous 
communities face disproportionate risks from the impacts of climate 
change, particularly those communities impacted by degradation of 
natural and cultural resources within established reservation 
boundaries and threats to traditional subsistence lifestyles. 
Indigenous communities whose health, economic well-being, and cultural 
traditions depend upon the natural

[[Page 63142]]

environment will likely be affected by the degradation of ecosystem 
goods and services associated with climate change. The IPCC indicates 
that losses of customs and historical knowledge may cause communities 
to be less resilient or adaptable.\134\ The NCA4 (2018) noted that 
while indigenous peoples are diverse and will be impacted by the 
climate changes universal to all Americans, there are several ways in 
which climate change uniquely threatens indigenous peoples' livelihoods 
and economies.\135\ In addition, there can be institutional barriers 
(including policy-based limitations and restrictions) to their 
management of water, land, and other natural resources that could 
impede adaptive measures.
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    \134\ Porter et al., 2014: Food security and food production 
systems.
    \135\ Jantarasami, L.C., R. Novak, R. Delgado, E. Marino, S. 
McNeeley, C. Narducci, J. Raymond-Yakoubian, L. Singletary, and K. 
Powys Whyte, 2018: Tribes and Indigenous Peoples. In Impacts, Risks, 
and Adaptation in the United States: Fourth National Climate 
Assessment, Volume II [Reidmiller, D.R., C.W. Avery, D.R. 
Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. 
Stewart (eds.)]. U.S. Global Change Research Program, Washington, 
DC, USA, pp. 572-603. doi: 10.7930/NCA4. 2018. CH15.
---------------------------------------------------------------------------

    For example, indigenous agriculture in the Southwest is already 
being adversely affected by changing patterns of flooding, drought, 
dust storms, and rising temperatures leading to increased soil erosion, 
irrigation water demand, and decreased crop quality and herd sizes. The 
Confederated Tribes of the Umatilla Indian Reservation in the Northwest 
have identified climate risks to salmon, elk, deer, roots, and 
huckleberry habitat. Housing and sanitary water supply infrastructure 
are vulnerable to disruption from extreme precipitation events. 
Confounding general Native American response to natural hazards are 
limitations imposed by policies such as the Dawes Act of 1887 and the 
Indian Reorganization Act of 1934, which ultimately restrict Indigenous 
peoples' autonomy regarding land-management decisions through Federal 
trusteeship of certain Tribal lands and mandated Federal oversight of 
management decisions. Additionally, NCA4 noted that Indigenous peoples 
are subjected to institutional racism effects, such as poor 
infrastructure, diminished access to quality healthcare, and greater 
risk of exposure to pollutants. Consequently, Native Americans often 
have disproportionately higher rates of asthma, cardiovascular disease, 
Alzheimer's disease, diabetes, and obesity. These health conditions and 
related effects (e.g., disorientation, heightened exposure to 
PM2.5, etc.) can all contribute to increased vulnerability 
to climate-driven extreme heat and air pollution events, which also may 
be exacerbated by stressful situations, such as extreme weather events, 
wildfires, and other circumstances.
    NCA4 and IPCC's Fifth Assessment Report \136\ also highlighted 
several impacts specific to Alaskan Indigenous Peoples. Coastal erosion 
and permafrost thaw will lead to more coastal erosion, rendering winter 
travel riskier and exacerbating damage to buildings, roads, and other 
infrastructure--impacts on archaeological sites, structures, and 
objects that will lead to a loss of cultural heritage for Alaska's 
indigenous people. In terms of food security, the NCA4 discussed 
reductions in suitable ice conditions for hunting, warmer temperatures 
impairing the use of traditional ice cellars for food storage, and 
declining shellfish populations due to warming and acidification. While 
the NCA4 also noted that climate change provided more opportunity to 
hunt from boats later in the fall season or earlier in the spring, the 
assessment found that the net impact was an overall decrease in food 
security.
---------------------------------------------------------------------------

    \136\ Porter et al., 2014: Food security and food production 
systems.
---------------------------------------------------------------------------

B. Impacted Stakeholders

    Based on analyses of exposed populations, the EPA has determined 
that this action, if finalized in a manner similar to what is proposed 
in this document, is likely to help reduce adverse effects of air 
pollution on minority populations, and/or low-income populations that 
have the potential for disproportionate impacts, as specified in E.O. 
12898 (59 FR 7629, February 16, 1994) and referenced in E.O. 13985 (86 
FR 7009, January 20, 2021). The EPA remains committed to engaging with 
communities and stakeholders throughout the development of this 
rulemaking and continues to invite comments on how the Agency can 
better achieve these goals through this action. For this proposed rule, 
we assessed emissions of HAP, criteria pollutants, and pollutants that 
cause climate change.
    For HAP emissions, we estimated cancer risks and the demographic 
breakdown of people living in areas with potentially elevated risk 
levels by performing dispersion modeling of the most recent NEI data 
from 2017, which indicates nationwide emissions of approximately 
110,000 tpy of over 40 HAP (including benzene, toluene, ethylbenzene, 
xylenes, and formaldehyde) from the Oil and Natural Gas Industry. Table 
12 gives the risk and demographic results for the Oil and Natural Gas 
Industry from this screening-level assessment. We estimate there are 
39,000 people with cancer risk greater than or equal to 100-in-1 
million attributable to oil and natural gas sources, with a maximum 
estimated risk of 200-in-1 million occurring in three census blocks (10 
people). We estimate there are about 143,000 people with estimated risk 
greater than or equal to 50-in-1 million, and about 6.8 million people 
with estimated cancer risk greater than 1-in-1 million. It is important 
to note that these estimates are subject to various types of 
uncertainty related to input parameters and assumptions, including 
emissions datasets, exposure modeling and the dose-response 
relationships.\137\
---------------------------------------------------------------------------

    \137\ See `Risk Report Template' at Docket ID No. EPA-HQ-OAR-
2021-0317.
---------------------------------------------------------------------------

    As shown in Table 12, Hispanic and Latino populations and young 
people (ages 0-17) are disproportionately represented in communities 
exposed to elevated cancer risks from oil and natural gas sources, 
while the proportion of people in other demographic groups with 
estimated risks above the specified levels is at or below the national 
average. The overall percent minority is about the same as the national 
average, but the percentage of people exposed to cancer risks greater 
than or equal to the 100-in-1 million and 50-in-1 million thresholds 
who are Hispanic or Latino is about 10 percentage points higher than 
the national average. The overall minority percentage is not elevated 
compared to the national average because the African-American 
percentage is much lower than the national average. The demographic 
group of people aged 0-17 is slightly higher than the national average.

[[Page 63143]]



                     Table 12--Cancer Risk and Demographic Population Estimates for 2017 NEI Nonpoint Oil and Natural Gas Emissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Risks >=100-in-1 million
                                              Risks >=50-in-1 million
                                               Risks >1-in-1 million        Nationwide
--------------------------------------------------------------------------------------------------------------------------------------------------------
Total Population                                      39,000
                                                      143,000
                                                     6,805,000            ..............
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                              Population               %      Population               %      Population               %               %
--------------------------------------------------------------------------------------------------------------------------------------------------------
Minority................................          13,268            34.1          52,154            36.5       2,010,161            29.5            39.9
African American........................             140             0.4           1,434             1.0         535,055             7.9            12.2
Native American.........................              77             0.2             465             0.3          59,087             0.9             0.7
Other and Multiracial...................           1,443             3.7           5,148             3.6         323,397             4.8             8.2
Hispanic or Latino......................          11,608            29.9          45,107            31.6       1,092,621            16.1            18.8
Age 0-17................................          10,679            27.5          37,487            26.2       1,463,907            21.5            22.6
Age >=65................................           4,272            11.0          17,188            12.0       1,085,067            15.9            15.7
Below the Poverty Level.................           2,000             5.1          13,455             9.4         902,472            13.2            13.4
Over 25 Without a High School Diploma...           2,788             7.2          11,320             7.9         488,372             7.2            12.1
Linguistically Isolated.................             808             2.1           4,418             3.1         179,739             2.6             5.4
--------------------------------------------------------------------------------------------------------------------------------------------------------

    For criteria pollutants, we assessed exposures to ozone from Oil 
and Natural Gas Industry VOC emissions across races/ethnicities, ages, 
and sexes in a recent baseline (pre-control) air quality scenario. 
Annual air quality was simulated using a photochemical model for the 
year 2017, based on emissions from the most recent NEI. The analysis 
shows that the distribution of exposures for all demographic groups 
except Hispanic and Asian populations are similar to or below the 
national average or a reference population. Differences between 
exposures in Hispanic and Asian populations versus White or all 
populations are modest, and the results are subject to various types of 
uncertainty related to input parameters and assumptions.
    In addition to climate and air quality impacts, the EPA also 
conducted analyses to characterize potential impacts on domestic oil 
and natural gas production and prices and to describe the baseline 
distribution of employment and energy burdens. Section XVI.d describes 
the results for our analysis of prices and production. For the 
distribution of baseline employment, we assessed the demographic 
characteristics of (1) workers in the oil and gas sector and (2) people 
living in oil and natural gas intensive communities.\138\ Comparing 
workers in the oil and natural gas sector to workers in other sectors, 
oil and natural gas workers may have higher than average incomes, be 
more likely to have completed high school, and be disproportionately 
Hispanic. People in some oil and gas intensive communities concentrated 
in Texas, Oklahoma, and Louisiana have lower average income levels, 
lower rates of high school completion, and higher likelihood of being 
non-Whites or hispanic than people living in communities that are not 
oil and gas intensive. Regarding household energy burden, low-income 
households, Hispanic, and Black households' energy expenditures may 
comprise a disproportionate share of their total expenditures and 
income as compared to higher income, non-Hispanic, and non-Black 
households, respectively. Results are presented in detail in the RIA 
accompanying this proposal.
---------------------------------------------------------------------------

    \138\ For this analysis, oil and natural gas intensive 
communities are defined as the top 20% of communities with respect 
to the proportion of oil and natural gas workers.
---------------------------------------------------------------------------

    In a proximity analysis of Tribes living within 50 miles of 
affected sources, we found 112 unique Tribal lands (Federally 
recognized Reservations, Off-Reservation Trust Lands, and Census 
Oklahoma Tribal Statistical Areas (OTSA)) located within 50 miles of a 
source with 32 Tribes having one or more sources located on Tribal 
land.
    Finally, the EPA has also analyzed prior enforcement actions 
related to air pollution from storage vessels, and identified 
improvements in air quality resulting from these actions as 
particularly important in communities with EJ concerns (identified 
using EJSCREEN).\139\ In a 2021 analysis of resolved enforcement 
matters, the EPA determined that communities with EJ concerns 
experience a disproportionate level of air pollution burden from 
storage vessel emissions. Although only about 25 percent of storage 
vessels were located in these communities with EJ concerns, 67 percent 
of the total emission reductions of VOCs, methane, PM, and 
NOX (about 95 million pounds) achieved through these 
enforcement resolutions occurred in communities with EJ concerns. This 
analysis suggests that the provisions of this proposed rule requiring 
installation of controls at storage vessels and monitoring and 
mitigation of fugitive emissions and malfunctions at storage vessels, 
would have particular benefits for these communities.
---------------------------------------------------------------------------

    \139\ See Memorandum ``Analysis of Environmental Justice Impacts 
of EPA's Historical Oil and Gas Storage Vessel Enforcement 
Resolutions (40 CFR part 60 subpart OOOO and OOOOa),'' located at 
Docket ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------

C. Outreach and Engagement

    The EPA identified stakeholder groups likely to be interested in 
this action and engaged with them in several ways including through 
meetings, training webinars, and public listening sessions to share 
information with stakeholders about this action, on how stakeholders 
may comment on the proposed rule, and to hear their input about the 
industry and its impacts as we were developing this proposal. 
Specifically, on May 27, 2021, the EPA held a webinar-based training 
designed for communities affected by this rule.\140\ This training 
provided an overview of the Crude Oil and Natural Gas Industry and how 
it is regulated and offered information on how to participate in the 
rulemaking process. The EPA also held virtual public listening sessions 
June 15 through June 17, 2021, and heard various community and health 
related themes from speakers who participated.\141\ \142\ Community 
themes

[[Page 63144]]

included concerns about protecting communities adjacent to oil and gas 
activities, providing monitoring and data so communities know what is 
in the air they are breathing, and upholding Tribal trust 
responsibilities. Community speakers urged the EPA to adopt stringent 
measures to reduce oil and natural gas pollution, and frequently cited 
an analysis suggesting such measures could achieve reductions of 65 
percent below 2012 levels by 2025.
---------------------------------------------------------------------------

    \140\ https://www.epa.gov/sites/default/files/2021-05/documents/us_epa_training_webinar_on_oil_and_natural_gas_for_communities.5.27.2021.pdf.
    \141\ June 15, 2021 session: https://youtu.be/T8XwDbf-B8g; June 
16, 2021 session: https://www.youtube.com/watch?v=l23bKPF-5oc; June 
17, 2021 session: https://www.youtube.com/watch?v=R2AZrmfuAXQ.
    \142\ Full transcripts for the listening sessions are posted at 
EPA Docket ID No. EPA-HQ-OAR-2021-0295.
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    Community Access to Emissions Information. Several stakeholders 
requested that the rule include requirements that provide communities 
with information, including fence line monitoring or ``better 
monitoring so people will know the air they are breathing.'' A few 
speakers expressed concerned about the correct placement of existing 
air monitors. Speakers from Texas described local air monitors 
monitoring meteorology and ozone, but not hazardous air pollutants, and 
called on the EPA to consider alternative monitoring for oil and 
natural gas sources such as fence-line monitors, along with guidance 
from the EPA to require monitors of oil and natural gas facilities in 
close proximity to parks, schools, and playgrounds.
    Health Concerns in Adjacent Communities. Speakers raised concerns 
about impacts on frontline communities and those communities adjacent 
to oil and natural gas operations. These stakeholders called on the EPA 
to propose and promulgate stricter standards or alternative 
requirements for sources adjacent to urban communities and close to 
where people live and work. Several speakers used the term ``energy 
sacrifice zone'' when discussing the disproportionate impacts of oil 
and natural gas operations on frontline communities. Speakers advocated 
that when developing this regulatory effort, consultation with 
frontline communities is essential, and some speakers cited a Center 
for Investigative Reporting report stating that 30,000 children in 
Arlington, Texas, attend school within half a mile of active oil and 
gas sites. Speakers discussed concerns about methane as a formaldehyde 
precursor and related health effects and cited examples of health 
effects including hydraulic fracturing chemicals being measured in 
blood or urine; increases in nosebleeds in people in areas of oil and 
natural gas development; headaches and cancer. These speakers included 
teenagers from Pennsylvania, who said they live within 1 mile of 33 
wellheads and 500 feet of a pipeline. Several people cited a February 
2018 blowout and explosion in Belmont County, Ohio, that was reported 
to release 60,000 tons of methane in 20 days and said that is more than 
some countries emit in a year. Speakers also expressed related 
environmental concerns such as water contamination and fresh drinking 
water being diverted for hydraulic fracturing. One speaker urged that 
information on local water use be provided in languages other than 
English, stating that in Big Spring (Howard County), Texas, the local 
government only provided information to use tap water ``at your own 
risk'' in English.
    Additional concerns raised by communities included: Local 
compressor stations having numerous planned and unplanned releases into 
adjacent communities, which appear to be during startup; whether the 
EPA will use a robust cost analysis to address the economic impacts of 
labor loss and gas costs resulting from any regulation; if plugged and 
abandoned wells included in this action, will this regulation apply to 
BLM land; will States be required to use the same emissions calculation 
used by the EPA for methane GWP; will there be disclosure of necessary 
data collection or technology to be used by the Oil and Natural Gas 
Industry to track and reduce methane emissions; and will the EPA 
consider the necessity of venting and flaring from a safety standpoint. 
Communities also discussed concerns about excess emissions from storage 
vessels and the need for clarifying the applicability of the standard 
in addition to improving enforceability and compliance at this type of 
facility.
    In addition to the trainings and listening sessions, the EPA 
engaged with community leaders potentially impacted by this proposed 
action by hosting a meeting with EJ community leaders on May 14, 2021. 
As noted above, the EPA provided the public with factual information to 
help them understand the issues addressed by this action. We obtained 
input from the public, including communities, about their concerns 
about air pollution from the oil and gas industry, including receiving 
stakeholder perspectives on alternatives. The EPA considered and 
weighed information from communities as the agency developed this 
proposed action.
    In addition to the engagement conducted prior to this proposal, the 
EPA is providing the public, including those communities 
disproportionately impacted by the burdens of pollution, opportunities 
to engage in the EPA's public comment period for this proposal, 
including by hosting public hearings. This public hearing will occur 
according to the schedule identified in the DATES and SUPPLEMENTARY 
INFORMATION section of this preamble to discuss:
     What impacts they are experiencing (i.e., health, noise, 
smells, economic),
     How the community would like the EPA to address their 
concerns,
     How the EPA is addressing those concerns in the 
rulemaking, and
     Any other topics, issues, concerns, etc. that the public 
may have regarding this proposal.
    For more information about the EPA's pre-proposal outreach 
activities, please see EPA Docket ID No. EPA-HQ-OAR-2021-0295. Please 
refer to EPA Docket ID No. EPA-HQ-OAR-2021-0317 for submitting public 
comments on this proposed rulemaking. For public input to be considered 
during the formal rulemaking, please submit comments on this proposed 
action to the formal regulatory docket at EPA Docket ID No. EPA-HQ-OAR-
2021-0317 so that the EPA may consider those comments during the 
development of the final rule.

D. Environmental Justice Considerations

    The EPA considered EJ implications in the development of this 
proposed rulemaking process, including the fair treatment and 
meaningful involvement of all people regardless of race, color, 
national origin, or income. As part of this process, the EPA engaged 
and consulted with frontline communities through interactions such as 
webinars, listening sessions and meetings. These opportunities gave the 
EPA a chance to hear directly from the public, especially overburdened 
and underserved communities, on the development of the proposed rule. 
The EPA considered these community concerns throughout our internal 
development process that resulted in this proposal which, if finalized 
in a manner similar to what is being proposed, will reduce emissions of 
harmful air pollutants, promote gas capture and beneficial use, and 
provide opportunity for flexibility and expanded transparency in order 
to yield a consistent and accountable national program. The EPA's 
proposed NSPS and EG are summarized in sections XI and XII below. 
Anticipated impacts of this action are discussed further in section XVI 
of this preamble.
    In recognizing that minority and low-income populations often bear 
an unequal burden of environmental harms and risks, the EPA continues 
to consider

[[Page 63145]]

ways to protect them from adverse public health and environmental 
effects of air pollution emitted from sources within the Oil and 
Natural Gas Industry that are addressed in this proposed rulemaking. 
For these reasons, in section XIV.C the EPA is proposing to include an 
additional requirement associated with the adoption and submittal of 
State plans pursuant to EG OOOOc (in addition to the current 
requirements of Subpart Ba) by requiring States to meaningfully engage 
with members of the public, including overburdened and underserved 
communities, during the plan development process and prior to adoption 
and submission of the plan to the EPA. The EPA is proposing this 
specific meaningful engagement requirement to ensure that the State 
plan development process is inclusive, effective, and accessible to 
all.
    Details of the EPA's assessment of EJ considerations can be found 
in the RIA for this action. The EPA seeks input on the EJ analyses 
contained in the RIA, as well as broader input on other health and 
environmental risks the Agency should assess in the comprehensive 
development of this proposed action. In particular, the EPA is 
soliciting comment on key assumptions underlying the EJ analysis as 
well as data and information that would enable the Agency to conduct a 
more nuanced analysis of HAP and criteria pollutant exposure and risk, 
given the inherent uncertainty regarding risk assessment. More broadly, 
the EPA seeks information, analysis, and comment on how the provisions 
of this proposed action would affect air pollution and health in 
communities with environmental justice concerns, and whether there are 
further provisions that EPA should consider as part of a supplemental 
proposal or a final rule that would enhance the health and 
environmental benefits of this rule for these communities.

VII. Other Stakeholder Outreach

A. Educating the Public, Listening Sessions, and Stakeholder Outreach

    The EPA began the development of this proposed action to reduce 
methane and other harmful pollutants from new and existing sources in 
the Crude Oil and Natural Gas source category with a public outreach 
effort to gather a broad range of stakeholder input. This effort 
included: Opening a public docket for pre-proposal input; \143\ holding 
training sessions providing overviews of the industry, the EPA's 
rulemaking process and how to participate in it; and convening 
listening sessions for the public, including a wide range of 
stakeholders. The EPA additionally held roundtables with State 
environmental commissioners through the Environmental Council of the 
States, and oil and gas commissioners and staff through the Interstate 
Oil and Gas Compact Commission (IOGCC), and met with non-governmental 
organizations (NGOs), industry, and the U.S. Climate Alliance, among 
others.\144\
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    \143\ EPA Docket ID No. EPA-HQ-OAR-2021-0295.
    \144\ A full list of pre-proposal meetings the EPA participated 
in is included at EPA Docket ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------

    In addition to the trainings and listening sessions noted in 
section VI above, on May 25 and 26, 2021, the EPA held webinar-based 
trainings designed for small business stakeholders \145\ and Tribal 
nations.\146\ The training provided an overview of the Oil and Natural 
Gas Industry and how it is regulated and offered information on how to 
participate in the rulemaking process. A combined total of more than 
100 small business stakeholders and Tribal nations participated. During 
the training, small business stakeholders expressed interest in 
learning more about the EPA's plan to either modify the 2016 NSPS OOOOa 
or take more substantial action in this proposal. For Tribal nations, 
the EPA has assessed potential impacts on Tribal nations and 
populations and has engaged with Tribal stakeholders to hear concerns 
associated with air pollution emitted from sources within the Oil and 
Natural Gas Industry that are addressed in this proposed rulemaking. 
Tribal members mentioned the need for the EPA to uphold its trust 
responsibilities, propose and promulgate rules that protect 
disproportionately impacted communities, and asked that the EPA 
allocate resources for Tribal governments to implement regulations 
through Tribal air quality programs.
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    \145\ https://www.epa.gov/sites/default/files/2021-05/documents/oil_and_gas_training_webinar_small_businesses_05.25.21.pdf.
    \146\ https://www.epa.gov/sites/default/files/2021-05/documents/usepa_training_webinar_on_oil_and_natural_gas_for_tribes.5.26.2021.pdf.
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    As noted above, the EPA also heard from a broad range of 
stakeholders during virtual public listening sessions held from June 15 
through June 17, 2021,\147\ which featured a total of 173 
speakers.\148\ Many speakers stressed the urgent need to address 
climate change and the importance of reducing methane pollution as part 
of the nation's overall response to climate change. In addition to the 
community perspectives described above, the Agency also heard from 
industry speakers who were generally supportive of the regulation and 
stressed the need to provide compliance flexibility and allow industry 
the ability to use cutting-edge tools, including measurement tools, to 
implement requirements. Technical comments from other speakers also 
focused on a need for robust methane monitoring and fugitive emissions 
monitoring, a need to strengthen standards for flares as a control for 
associated gas, and suggestions to improve compliance. The sections 
below provide additional details on the information presented by 
stakeholders during these listening sessions.
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    \147\ June 15, 2021 session: https://youtu.be/T8XwDbf-B8g; June 
16, 2021 session: https://www.youtube.com/watch?v=l23bKPF-5oc; June 
17, 2021 session: https://www.youtube.com/watch?v=R2AZrmfuAXQ.
    \148\ Full transcripts for the listening sessions are posted in 
at EPA Docket ID No. EPA-HQ-OAR-2021-0295.
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1. Technical Themes
    Measurement and Monitoring. Stakeholders advocated that the EPA 
modernize the rule by employing next-generation tools for methane 
identification and quantification, particularly for large emission or 
``super-emissions'' events. Stakeholders particularly focused on 
allowing the use of remote sensing to help industry more easily comply 
with monitoring requirements at well pads, which are numerous and 
geographically spread out in some States. Stakeholders specified the 
desire to use innovative remote sensing technologies to monitor 
fugitive emissions and large emission events, including aerial, truck-
based, satellite, and continuous monitoring. Several speakers focused 
on the need for regular monitoring, repair, and reporting, including 
ambient air monitoring in oil and natural gas development areas, as 
well as suggesting that the EPA pursue more robust methane monitoring 
for fugitive emissions, ensure that repair is completed, and pursue 
robust monitoring and reporting to verify the efficacy of the 
regulations.
    Implementation, Compliance, and Enforcement. Numerous stakeholders 
raised concerns about flaring of associated gas and advocated for more 
stringent standards to ensure that flares used as control devices 
perform effectively. One speaker, an OGI expert, noted seeing many 
flares that were not operating the way they were intended to and that 
were not adequately designed (e.g., unlit flares and ignition gas not 
being close enough to the waste gas stream to properly ignite). The 
speaker suggested that the EPA consider the concept of `thermal tuning' 
of flares by

[[Page 63146]]

using OGI to see if a plume of unburned hydrocarbons extends downwind 
from the flare, to ensure that flares are actually operating 
effectively; the speaker suggested that this use of OGI could be done 
in conjunction with fugitive emissions monitoring to make sure controls 
are working. Stakeholders further emphasized the need for recordkeeping 
of any inspections that are made (e.g., looking for flare damage from 
burned tips, lightning strikes). Some stakeholders also requested that 
the EPA consider reducing or eliminating flaring of associated gas and 
incentivizing capture. Lastly, one speaker raised concerns about 
flaring of associated gas in Texas and how flaring is permitted by the 
State. In response to these concerns, the EPA is proposing to reduce 
venting and flaring of associated gas and to require monitoring of 
flares to detect malfunctions. Further, the EPA is soliciting comment 
on whether to adopt additional measures to assure proper design and 
operation of control devices, including flares, as discussed in section 
XIII.
    Stakeholders raised other implementation, compliance, and 
enforcement concerns, including calls for the EPA to develop rules that 
are easy to apply and implement given States' limited budgets. 
Stakeholders cautioned that ``flexibility'' in a rule can be 
interpreted as a ``loophole,'' and opined that a rule that sets clear 
and uniform expectations will help avoid confusion. At the same time, 
speakers stated that a ``prescriptive checklist'' does not work in 
today's environment and recommended that the EPA modernize the 
regulatory approach. Several speakers, including speakers from Texas 
and North Dakota, raised concerns about the limited enforcement 
capacity of local and State governments, as well as the EPA and its 
regional officials and stated that this may result in implementation 
gaps. Speakers called on the EPA to have a third-party verification or 
audit requirements for fugitive emissions and cited to Texas's 
requirement for third-party audits to evaluate operator LDAR programs 
for highly reactive VOC. Speakers also cited to the public-facing 
Environmental Defense Fund (EDF) methane map \149\ with geotags of 
sources with observed hydrocarbon emissions, which provides operators 
an opportunity to respond to posted leak videos and measurements. 
Lastly, one speaker requested that the EPA not allow exemptions for 
start-up and shutdown emissions events. The EPA is soliciting comment 
on ways to utilize credible emissions information obtained from 
communities and others, as discussed in section XI.A.1.
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    \149\ https://www.permianmap.org.
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    Wells and Storage. Some stakeholders requested that the EPA 
consider a program for capping abandoned wells to ensure those wells 
are properly closed and not leaking. Speakers called on the EPA to 
consider abandoned and unplugged wells in the context of EJ communities 
adjacent to affected facilities and requested that the EPA incentivize 
appropriate well closure. In response to this input and to gather 
information that will be needed to inform possible future actions, the 
EPA is soliciting comment on ways to address abandoned wells, including 
potential closure requirements. See section XIII.B. Stakeholders also 
focused on marginal wells and asked that the EPA consider system-wide 
reductions be allowed, for example, at the basin level, and expressed 
challenges of retrofitting existing well sites and low production well 
sites where addition of control devices or closed vent systems would be 
necessary. Some speakers raised concern about ensuring that facilities 
are engineered for the basin or target formation from which they 
produce.
    Job Creation. Some speakers stated that this rulemaking is a job 
creation rule and encouraged a ``next generation'' approach to methane 
standards, such as incentivizing continuous monitoring. Other speakers 
cited a study about job creation in the methane mitigation 
industry.\150\
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    \150\ Stakeholders submitted the following studies to the pre-
proposal docket: https://www.regulations.gov/comment/EPA-HQ-OAR-2021-0295-0016 and https://www.regulations.gov/comment/EPA-HQ-OAR-2021-0295-0017.
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    Inventory, Loss Rates, and Methane Global Warming Potential. 
Several speakers criticized the EPA's emission inventories stating that 
the EPA is not using the correct data in its inventory, that the GHGI 
data is inaccurate because it relies on facility reporting of emissions 
from calculations and estimation methods rather than measurement and 
monitoring, and suggested that the EPA rely on monitoring and 
measurement of actual emissions and subsequently make the monitoring 
data publicly available. Speakers raised issues with differences in 
inventories across Federal agencies, contrasting DOE's Environmental 
Impact Statements and EPA's NEI. Stakeholders suggested that the EPA 
use data collected by EDF and other researchers, which calculated 
methane emissions to be 60 percent higher than the EPA's 
estimates.\151\ Speakers also mentioned the amount of methane that is 
lost from wells each year, providing varying estimates of these 
emissions. Lastly, stakeholders called on the EPA to use the 20-year 
GWP for methane, instead of the 100-year value the agency uses.
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    \151\ Alvarez et al. 2018. Assessment of methane emissions from 
the U.S. oil and gas supply chain. Science 13 Jul 2018: Vol. 361, 
Issue 6398, pp. 186-188.
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2. Climate and Other Themes
    Several speakers mentioned the effects of climate change from oil 
and natural gas methane emissions, such as impacts on farmland, 
wildfires, and transmission of tick-borne pathogens. Many speakers 
pointed out the extreme heat and drought that currently are affecting 
the western U.S. Stakeholders asked that the EPA examine the impacts of 
the Oil and Natural Gas Industry on small businesses that are not part 
of the regulated community, such as businesses that rely on outdoor 
recreation or water flow that could be affected by oil and natural gas 
operations. A speaker raised concerns about the impact of the industry 
on tourism, saying that 30 percent of their local economy relies on 
tourism and outdoor recreation. Lastly, a speaker discussed pipeline 
weatherization needs and suggested that the EPA and other Federal 
agencies account for seasonal variability.
    In addition to the public listening sessions, on June 29, 2021, the 
EPA met with environmental commissioners and staff through the 
Environmental Council of the States (ECOS). Subsequently, on July 12, 
2021, the EPA participated in a roundtable with members of the IOGCC. 
The discussions in both roundtables included air emissions monitoring 
technologies and interactions between the EPA's requirements and State 
rules. For the ECOS roundtable, the EPA also sought feedback on and 
implementation of the EPA's current NSPS; for the IOGCC roundtable, the 
EPA also requested feedback on compliance with the rules.
    Key themes from both roundtables included the following: Allowing 
for the use of broad types of methane detection technologies; improving 
and streamlining the EPA's AMEL process, such as by structuring it so 
it could apply broadly rather than on a site-by-site basis; requests 
that expanded aspects of States' rules be deemed equivalent to the 
EPA's rule, and requests that the EPA's rule complement State 
regulations in a way that would not interrupt the work of State 
agencies requiring them to request State legislative approvals. Other 
common themes were requests that the rule

[[Page 63147]]

provide flexibility and be easy to implement, particularly for marginal 
or low production wells owned by independent small businesses, and that 
the EPA coordinate its rules with those of other Federal agencies, 
notably the DOI's BLM.
    Other input included the need to fill gaps by addressing additional 
opportunities to reduce emissions beyond the 2016 NSPS OOOOa, concerns 
about the complexity of the calculation for the potential to emit for 
storage vessels, a desire that the EPA's rule not slow momentum of 
voluntary efforts to reduce emissions, and a desire for regulations 
that recognize geographic differences.

B. EPA Methane Detection Technology Workshop

    The EPA held a virtual public workshop on August 23 and 24, 2021, 
to hear perspectives on innovative technologies that could be used to 
detect methane emissions from the Oil and Natural Gas Industry.\152\ 
The workshop focused on methane-sensing technologies that are not 
currently approved for use in the NSPS for the Oil and Natural Gas 
Industry, and how those technologies could be applied in the Crude Oil 
and Natural Gas sector. Panelists provided twenty-four live 
presentations during the workshop. The panelists all had firsthand 
experience evaluating innovative methane-sensing technologies or had 
used these technologies to identify methane emissions and presented 
about their experience. The live presentations were broken into six 
panel sessions, each focused on a particular topic, e.g., satellite 
measurements, methane sensors, aerial technologies. At the end of each 
panel session, the set of panelists participated in a question-and-
answer session. In addition to the live presentations, the workshop 
included a virtual exhibit hall for technology vendors to provide video 
presentations on their innovative technologies, with a focus on 
technology capability, applicability, and data quality. Forty-two 
vendors participated in the virtual vendor hall.
---------------------------------------------------------------------------

    \152\ https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry/epa-methane-detection-technology-workshop.
---------------------------------------------------------------------------

    Nine hundred sixty stakeholders registered to participate in the 
workshop. The workshop was also livestreamed, so stakeholders who could 
not attend could watch the recorded livestream later at their 
convenience. The registrants included a wide range of stakeholders 
including, academics, methane detection technology end-user and 
vendors, governmental employees (local, State, and Federal), and NGOs.

C. How is this information being considered in this proposal?

    The EPA's pre-proposal outreach effort was intended to gather 
stakeholder input to assist the Agency with developing this 
proposal.\153\ The EPA recognizes that tackling the dangers of climate 
change will require an ``all-hands-on deck'' approach through 
regulatory, voluntary, and community programs and initiatives. 
Throughout the development of this proposed rule, the EPA considered 
the stakeholders' experiences and lessons learned to help inform how to 
better structure this proposal and consider ongoing challenges that 
will require continued collaboration with stakeholders. The EPA will 
continue to consider the information obtained in developing this 
proposal as we take the next steps on the proposed regulations.
---------------------------------------------------------------------------

    \153\ The EPA opened a non-regulatory docket for stakeholder to 
submit early input. That early input can be found at EPA Docket I.D. 
Number EPA-HQ-OAR-2021-0295.
---------------------------------------------------------------------------

    With this proposal, the EPA seeks further input from the public and 
from all stakeholders affected by this rule. Throughout this action, 
unless noted otherwise, the EPA is requesting comments on all aspects 
of this proposal, including on several themes raised in the pre-
proposal outreach (e.g., innovative technologies for methane detection 
and quantification). Please see section XI.A.1 of this preamble for 
specific solicitations for comment regarding advanced measurement 
technologies and section XIII for solicitations for comments on 
additional emission sources. For public input to be considered on this 
proposal,\154\ please submit comments on this proposed action to the 
regulatory docket at EPA Docket ID No. EPA-HQ-OAR-2021-0317 so that the 
EPA may consider those comments during the development of the final 
rule.
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    \154\ Information submitted to the pre-proposal non-regulatory 
docket at Docket ID No. EPA-HQ-OAR-2021-0295 is not automatically 
part of the proposal record. For information and materials to be 
considered in the proposed rulemaking record, it must be resubmitted 
in the rulemaking docket at EPA Docket ID No. EPA-HQ-OAR-2021-0317.
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VIII. Legal Basis for Proposal Scope

    The EPA proposes in this rulemaking to revise certain NSPS and to 
promulgate additional NSPS for both methane and VOC emissions from new 
oil and gas sources in the production, processing, transmission and 
storage segments of the industry; and to promulgate EG to require 
States to regulate methane emissions from existing sources in those 
segments. The large amount of methane emissions from the Oil and 
Natural Gas Industry--by far, the largest methane-emitting industry in 
the nation--coupled with the adverse effects of methane on the global 
climate compel immediate regulatory action. This section explains EPA's 
legal justification for proceeding with this proposed action, including 
regulating methane and VOCs from sources in all segments of the source 
category. The EPA first describes the history of our regulatory actions 
for oil and gas sources in 2016 and 2020--including the key legal 
interpretations and factual determinations made--as well as Congress's 
action in 2021 in response. The EPA then explains the implications of 
Congress's action and why we would come to the same conclusion even if 
Congress had not acted.
    This proposal is in line with our 2016 NSPS OOOOa rule, which 
likewise regulated methane and VOCs from all three segments of the 
industry. The 2016 NSPS OOOOa rule explained that these three segments 
should be regulated as part of the same source category because they 
are an interrelated sequence of functions in which pollution is 
produced from the same types of sources that can be controlled by the 
same techniques and technologies. That rule further explained that the 
large amount of methane emissions, coupled with the adverse effects of 
GHG air pollution, met the applicable statutory standard for regulating 
methane emissions from new sources through NSPS. Furthermore, the rule 
explained, this regulation of methane emissions from new sources 
triggered the EPA's authority and obligation to set guidelines for 
States to develop standards to regulate the overwhelming majority of 
oil and gas sources, which the CAA categorizes as ``existing'' sources. 
In the 2020 Policy Rule, the Agency reversed course, concluding based 
upon new legal interpretations that the rule concluded the EPA had not 
made the proper determinations necessary to issue such regulations. 
This action eliminated the Agency's authority and obligation to issue 
EG for existing sources. In 2021, Congress adopted a joint resolution 
to disapprove the EPA's 2020 Policy Rule under the CRA. According to 
the terms of CRA, the 2020 Policy Rule is ``treated as though [it] had 
never taken effect,'' 5 U.S.C. 801(f), and as a result, the 2016 Rule 
is reinstated.
    In disapproving the 2020 Policy Rule under the CRA, Congress 
explicitly rejected the 2020 Policy Rule interpretations and embraced 
EPA's

[[Page 63148]]

rationales for the 2016 NSPS OOOOa rule. The House Committee on Energy 
& Commerce emphasized in its report that the source category ``is the 
largest industrial emitter of methane in the U.S.,'' and directed that 
``regulation of emissions from new and existing oil and gas sources, 
including those located in the production, processing, and transmission 
and storage segments, is necessary to protect human health and welfare, 
including through combatting climate change, and to promote 
environmental justice.'' H.R. Rep. No. 117-64, 3-5 (2021) (House 
Report). A statement from the Senate cosponsors likewise underscored 
that ``methane is a leading contributing cause of climate change,'' 
whose ``emissions come from all segments of the Oil and Gas Industry,'' 
and stated that ``we encourage EPA to strengthen the standards we 
reinstate and aggressively regulate methane and other pollution 
emissions from new, modified, and existing sources throughout the 
production, processing, transmission and storage segments of the Oil 
and Gas Industry under section 111 of the CAA.'' 167 Cong. Rec. S2282 
(April 28, 2021) (statement by Sen. Heinrich) (Senate Statement).\155\ 
The Senators concluded with a stark statement: ``The welfare of our 
planet and of our communities depends on it.'' Id. at S2283.
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    \155\ Sen. Heinrich stated that he made this statement on behalf 
of ``[Majority [l]eader Chuck Schumer, Chairman Tom Carper of the 
Committee on Environment and Public Works, Senator Angus King, 
Senator Edward Markey and [himself],'' who he described as ``leading 
supporters and sponsors of S.J. Res. 14. . . .'' Senate Statement at 
S. 2282. Thus, the Senate Statement should be considered an 
authoritative piece of the legislative history. It should be noted 
that the Joint Resolution was referred to the Senate Committee on 
Environment and Public Works and discharged from the committee by 
petition pursuant to 5 U.S.C. 802(c), https://www.congress.gov/bill/117th-congress/senate-joint-resolution/14/all-actions. As a result, 
the resolution was not accompanied by a report from the Senate 
committee.
---------------------------------------------------------------------------

    This proposal comports with the EPA's CAA section 111 obligation to 
reduce dangerous pollution and responds to the urgency expressed by the 
current Congress. With this proposal, the EPA is taking additional 
steps in the regulation of the Crude Oil and Natural Gas source 
category to protect human health and the environment. Specifically, the 
agency is proposing to revise certain of those NSPS, to add NSPS for 
additional sources, and to propose EG that, if finalized, would impose 
a requirement on States to regulate methane emissions from existing 
sources. As the EPA explained in the 2016 Rule, this source category 
collectively emits massive quantities of the methane emissions that are 
among those driving the grave and growing threat of climate change, 
particularly in the near term. 81 FR 35834, June 3, 2016. As discussed 
in section III above, since that time, the science has repeatedly 
confirmed that climate change is already causing dire health, 
environmental, and economic impacts in communities across the United 
States.
    Because the 2021 CRA resolution automatically reinstated the 2016 
Rule, which itself determined that the Crude Oil and Natural Gas Source 
Category included the transmission and storage segment and that 
regulation of methane emissions was justified, the EPA is authorized to 
take the regulatory actions proposed in this rule. As explained below, 
we are reaffirming those determinations as clearly authorized under any 
reasonable interpretation of section 111. Because the reinstatement of 
the 2016 Rule provides the only necessary predicate for this rule, and 
because, as described, the interpretations underlying this rule are 
sound, the EPA is not reopening them here.

A. Recent History of the EPA's Regulation of Oil and Gas Sources and 
Congress's Response

1. 2016 NSPS OOOOa Rule
    As described above, the 2016 NSPS OOOOa rule extended the NSPS for 
VOCs for new sources in the Crude Oil and Natural Gas source category 
and also promulgated NSPS for methane emissions from new sources. This 
rule contained several interpretations that were the bases for these 
actions, and that are important for present purposes. First, the EPA 
confirmed its position in the 2012 NSPS OOOO rule that the scope of the 
oil and gas source category included the transmission and storage 
segment, in addition to the production and processing segments that the 
EPA had regulated since 1984. The agency stated that it believed these 
segments were included in the initial listing of the source category, 
and to the extent they were not, the agency determined to add them as 
appropriately encompassed within the regulated source category. The EPA 
based this latter conclusion on the structure of the industry. In 
particular, the EPA emphasized that ``[o]perations 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,'' and further explained, ``[b]ecause they 
are interrelated, segments that follow others are faced with increases 
in throughput caused by growth in throughput of the segments preceding 
(i.e., feeding) them.'' 81 FR 35832, June 3, 2016. The EPA also 
recognized ``that some equipment (e.g., storage vessels, pneumatic 
pumps and compressors) are used across the oil and natural gas 
industry.'' Id. Having made clear that the Crude Oil and Natural Gas 
source category includes the transmission and storage segment, the EPA 
proceeded to promulgate NSPS for sources in that segment. Id. at 35826.
    Second, in promulgating NSPS for methane emissions for new sources 
in the source category, the EPA explained its decision to regulate GHGs 
for the first time from the source category. Noting that the plain 
language of CAA section 111 requires a significant-contribution 
analysis only when EPA regulates a new source category, not a new 
pollutant, the Agency stated that it ``interprets CAA section 
111(b)(1)(B) to provide authority to establish a standard for 
performance for any pollutant emitted by that source category as long 
as the EPA has a rational basis for setting a standard for the 
pollutant.'' 81 FR 35842, June 3, 2016. In the alternative, if a 
rational-basis analysis were deemed insufficient, the EPA explained 
that it also concluded that GHG emissions, in the form of methane 
emissions, from the regulated Crude Oil and Natural Gas source category 
significantly contribute to dangerous pollution. Id. at 81 FR 35843, 
and 35877. In making the rational basis and alternative significant 
contribution findings, the EPA focused on ``the high quantities of 
methane emissions from the Crude Oil and Natural Gas source category.'' 
Id. The EPA emphasized, among other things, that ``[t]he Oil and 
Natural Gas source category is the largest emitter of methane in the 
U.S., contributing about 29 percent of total U.S. methane emissions.'' 
Id. The EPA added that ``[t]he methane that this source category emits 
accounts for 3 percent of all U.S. GHG emissions . . . [and] GWP-
weighted emissions of methane from these sources are larger than 
emissions of all GHGs from about 150 countries.'' Id. The EPA concluded 
that ``the[se] facts . . . along with prior EPA analysis'' concerning 
the effect of GHG air pollution on public health and welfare, 
``including that found in the 2009 Endangerment Finding, provide a 
rational basis for regulating GHG emissions from affected oil and gas 
sources . . .'' as well as for concluding in the alternative that oil 
and gas methane significantly contributes to dangerous pollution. Id. 
at 35843.
    In addition, in the 2016 NSPS OOOOa Rule, EPA recognized that 
promulgation of NSPS for methane emissions under

[[Page 63149]]

section 111(b)(1)(B) triggered the requirement that EPA promulgate EG 
to require States to regulate methane emissions from existing sources 
under section 111(d)(1), and described the steps it was taking to lay 
the groundwork for that regulation. 81 FR at 35831.
2. 2020 Policy Rule
    The 2020 Policy Rule rescinded key elements of the 2016 NSPS OOOOa 
rule based on different factual assertions and statutory 
interpretations than in the 2016 Rule. Specifically, the 2020 Policy 
Rule stated that it ``contains two main actions,'' 85 FR 57019, 
September 14, 2020 which it identified as follows: ``First, the EPA is 
finalizing a determination that the source category includes only the 
production and processing segments of the industry and is rescinding 
the standards applicable to the transmission and storage segment of the 
industry. . . .'' Id. The rule justified this first action in part on 
the grounds that ``the processes and operations found in the 
transmission and storage segment are distinct from those found in the 
production and processing segments,'' because ``the purposes of the 
operations are different'' and 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.'' Id. at 57028. ``Second, the EPA is separately 
rescinding the methane requirements of the NSPS applicable to sources 
in the production and processing segments.'' Id. EPA justified the 
rescission of the methane NSPS on two grounds. One was the EPA's 
``conclu[sion] that those methane requirements are redundant with the 
existing NSPS for VOC and, thus, establish no additional health 
protections.'' Id. at 57019. The second was a statutory interpretation: 
the EPA rejected the rational basis interpretation of the 2016 Rule, 
and stated that instead, ``[t]he EPA interprets [the relevant 
provisions in CAA section 111] . . . to require, or at least to 
authorize the Administrator to require, a pollutant-specific SCF as a 
predicate for promulgating a standard of performance for that air 
pollutant.'' Id. at 57035. The rule went on to ``determine that the SCF 
for methane that the EPA made in the alternative in the 2016 [NSPS 
OOOOa] Rule was invalid and did not meet this statutory standard,'' for 
two reasons: (i) ``[t]he EPA made that finding on the basis of methane 
emissions from the production, processing, and transmission and storage 
segments, instead of just the production and processing segments''; and 
(ii) ``the EPA failed to support that finding with either established 
criteria or some type of reasonably explained and intelligible standard 
or threshold for determining when an air pollutant contributes 
significantly to dangerous air pollution.'' Id. at 57019. The rule 
recognized that ``by rescinding the applicability of the NSPS . . . to 
methane emissions for [oil and gas] sources . . . existing sources . . 
. will not be subject to regulation under CAA section 111(d).'' Id. at 
57040.
3. CRA Resolution Disapproving the 2020 Policy Rule and Reinstating the 
2016 NSPS OOOOa Rule
    On June 30, 2021, the President signed into law a joint resolution 
adopted by Congress under the CRA disapproving the 2020 Policy Rule. By 
the terms of the CRA, this disapproval means that the 2020 Policy Rule 
is ``treated as though [it] had never taken effect.'' 5 U.S.C. 801(f). 
As a result, upon the disapproval, by operation of law, the 2016 NSPS 
OOOOa rule was reinstated, including the inclusion of the transmission 
and storage segment in the source category, the VOC NSPS for sources in 
that segment, and the methane NSPS for sources across the source 
category. And with the reinstatement of the methane NSPS, the EPA's 
obligation to issue EG to require States to regulate existing sources 
for methane emissions was reinstated as well. Moreover, the CRA bars an 
agency from promulgating ``a new rule that is substantially the same 
as'' a disapproved rule. 5 U.S.C. 801(b)(2).
    The accompanying legislative history, specifically a House 
Committee report (H.R. Rep. 117-64) and a statement on the Senate floor 
by the sponsors of the CRA resolution (Senate Statement at S2282-83), 
provides additional specificity regarding Congress's intent in 
disapproving 2020 Policy Rule and reinstating the 2016 Rule with regard 
to the scope of the source category and the regulation of methane.
a. Regulation of Transmission and Storage Sources
    The House Report rejected the 2020 Policy Rule's removal of the 
transmission and storage segment from the Crude Oil and Natural Gas 
Source Category, and its rescission of the VOC and methane NSPS 
promulgated in the 2012 NSPS OOOO and 2016 NSPS OOOOa rules for 
transmission and storage sources. House Report at 7; 85 FR 57029, 
September 14, 2020 (2020 Policy Rule). The Report recognized that in 
authorizing the EPA to list for regulation ``categories of sources'' 
under section 111(b)(1)(A) of the CAA, Congress ``provided the EPA with 
wide latitude to determine the scope of a source category . . . and to 
expand the scope of an already-listed source category if the agency 
later determines that it is reasonable to do so.'' House Report at 7. 
The Report stated that in the 2016 NSPS OOOOa, ``EPA correctly 
determined that the equipment and operations at production, processing, 
and transmission and storage facilities are a sequence of functions 
that are interrelated and necessary for the overall purpose of 
extracting, processing, and transporting natural gas for 
distribution.'' Id.; see 81 FR 35832, June 3, 2016 (2016 Rule). The 
Report added that the 2016 NSPS OOOOa also ``correctly determined that 
the types of equipment used and the emissions profile of the natural 
gas in the transmission and storage segments do not so distinctly 
differ from the types of equipment used and the emissions profile of 
the natural gas in the production and processing segments as to require 
that the EPA create a separate source category listing.'' House Report 
at 7; see 81 FR 35832, June 3, 2016. The Report went on to reject the 
2020 Policy Rule's basis for excluding the transmission and storage 
segment, finding that the functions of the various segments in the 
Crude Oil and Natural Gas sector are all ``interrelated and necessary 
for the overall purpose'' of the industry, House Report at 7, and that 
EPA correctly determined in 2016 that the source types and emissions 
found in the transmission and storage segment are sufficiently similar 
to production and processing as to justify regulating these segments in 
a single source category. Id.
    The Senate Statement was also explicit that the 2020 Policy Rule 
erred in rescinding NSPS for sources in the transmission and storage 
segment:

[T]he resolution clarifies our intent that EPA should regulate 
methane and other pollution emissions from all oil and gas sources, 
including production, processing, transmission, and storage segments 
under the authority of section 111 of the CAA. In addition, we 
intend that section 111 . . . obligates and provides EPA with the 
legal authority to regulate existing sources of methane emissions in 
all of these segments.

Senate Statement at S2283 (paragraphing revised).
b. Regulation of Methane--Redundancy
    The House Report and Senate Statement made clear Congress's view 
that in light of the large amount of methane emissions from oil and gas 
sources and their impact on global climate, the EPA must regulate those

[[Page 63150]]

emissions under section 111. House Report at 5; Senate Statement at 
S2283. Both pieces of legislative history specifically rejected the 
2020 Policy Rule's rescission of the methane NSPS. House Report at 7; 
Senate Statement at S2283. Moreover, the legislative history 
specifically rejected the statutory interpretations of section 111 that 
formed the bases of EPA's 2020 rationales for rescinding the methane 
NSPS. House Report at 7-10; see Senate Statement at S2283; see 85 FR 
57033, 57035-38 (September 14, 2020).
    The House Report began by recognizing the critical importance of 
regulating methane emissions from oil and gas sources, emphasizing both 
the potency of methane in driving global warming, and the massive 
amounts of methane emitted each year by the oil and gas industry. House 
Report at 3-4. The House Report was clear that the amount of these 
emissions and their impact compelled regulatory action. Id. at 5. The 
Senate Statement was equally clear:

[M]ethane is a leading contributing cause of climate change. It is 
28 to 36 times more powerful than carbon dioxide in raising the 
Earth's surface temperature when measured over a 100-year time scale 
and about 84 times more powerful when measured over a 20-year 
timeframe.
    Industrial sources emit GHG in great quantities, and methane 
emissions from all segments of the Oil and Gas Industry are 
especially significant in their contribution to overall emissions 
levels and surface temperature rise. . . .
    In fact, with the congressional adoption of this resolution, we 
encourage EPA to strengthen the standards we reinstate and 
aggressively regulate methane and other pollution emissions from 
new, modified, and existing sources throughout the production, 
processing, transmission, and storage segments of the Oil and Gas 
Industry under section 111 of the Clean Air Act.
    The welfare of our planet and of our communities depend on it.

Senate Statement at S2283.
    Turning to the 2020 Policy Rule, the House Report rejected the 
rule's position that the methane NSPS were redundant to the VOC NSPS, 
and therefore unnecessary. House Report at 7. The House Report rejected 
the 2020 Policy Rule's ``redundancy'' rationale, explaining that in the 
2016 NSPS OOOOa, the EPA had consciously ``formulated [the two sets of 
NSPS so as] to impose the same requirements for the same types of 
equipment,'' and that the co-extensive nature of the NSPS mean that 
``sources could comply with them in an efficient manner,'' not that the 
NSPS were redundant. Id. The House report further rejected the 2020 
Policy Rule's assertion that it need not take into account the 
implications of regulating methane for existing sources, calling it a 
``fundamental misinterpretation of section 111, and the critical 
importance of section 111(d) in Congress [sic: Congress's] scheme.'' 
House Report at 8 & n. 27 (The EPA's 2020 ``misinterpretation . . . was 
glaring and enormously consequential'' because it precluded regulation 
of methane from existing sources). The House Report emphasized that 
``existing sources emit the vast majority of methane in the oil and gas 
sector,'' id. and pointed out that while the 2016 NSPS ``covered 
roughly 60,000 wells constructed since 2015[, t]here are more than 
800,000 existing wells in operation. . . .''Id. n.28.
    The Senate Statement also made clear that the resolution of 
disapproval ``reaffirms that the CAA requires EPA to act to protect 
Americans from sources of . . . methane,'' ``reject[s] the [2020 Policy 
Rule's] misguided legal interpretations,'' and ``clarifies our intent 
that EPA should regulate methane . . . from all oil and gas sources. . 
. .'' Senate Statement at 2283.
c. Regulation of Methane--Significant Contribution Finding
    The legislative history was explicit that, contrary to the EPA's 
statutory interpretation in the 2020 Policy Rule, section 111 of the 
CAA, by its plain language, does not require, or authorize the EPA to 
require, as a prerequisite for promulgating NSPS for a particular air 
pollutant from a listed source category, a separate finding by the EPA 
that emissions of the pollutant from the source category contribute 
significantly to dangerous air pollution. House Report at 9-10; Senate 
Statement at S2283. The House Report rejected this interpretation. It 
made clear that instead, consistent with the EPA's statements in the 
2016 NSPS OOOOa and the plain language of the CAA, section 111 requires 
that the agency must make a SCF only at ``the first step of the 
process, the listing of the source category,'' and further requires 
that this finding ``must apply to the impact of the `category of 
sources' on `air pollution' '' as opposed to individual pollutants. 
House Report at 9. The House Report went on to explain that this 
provision ``does not require the EPA to make a SCF for individual air 
pollutants emitted from the source category, nor does it even mention 
individual air pollutants,'' id. at 9. The House Report went on to 
explain in some detail the meaning that the EPA should give to section 
111, which, consistent with the 2016 Rule, is that section 111 
authorizes the agency to promulgate NSPS for particular pollutants as 
long as it has a rational basis for doing so. House Report at 8-9. The 
report explained that after the EPA lists a source category for 
regulation under section 111(b)(1)(A), it is required to determine for 
which pollutants to promulgate NSPS, and this determination is subject 
to CAA section 307(d)(9)(A) (``In the case of review of any [EPA] 
action . . . to which [section 307(d)] applies, the court may reverse 
any such action found to be arbitrary, capricious, an abuse of 
discretion, or otherwise not in accordance with law'').\156\ The Report 
further noted that the U.S. Supreme Court affirmed this interpretation 
in American Electric Power Co. Inc. v. Connecticut, 564 U.S. 410, 427 
(2011) (American Electric Power) (``EPA may not decline to regulate 
carbon-dioxide emissions from powerplants if refusal to act would be 
`arbitrary, capricious, an abuse of discretion, or otherwise not in 
accordance with law'' (citing section 307(d)(9)(A)). The Report went on 
to note that the 2016 NSPS OOOOa had stated that the EPA was authorized 
to promulgate a NSPS for a particular pollutant if it had a ``rational 
basis'' for doing so, and the Report emphasized that this ``rational 
basis'' standard is ``fully consistent with'' the arbitrary and 
capricious standard under section 307(d)(9)(A) of the CAA. House Report 
at 9.\157\
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    \156\ Section 307(d) applies to the promulgation of NSPS, under 
section 307(d)(1)(C).
    \157\ The House Report dismissed the 2020 Policy Rule's 
criticism of the rational basis test as unduly vague by noting that 
a court could enforce it. House Report at 11.
---------------------------------------------------------------------------

    The House Report further explained that, in contrast, the 2020 
Policy Rule's statutory interpretation of section 111 to require a 
pollutant-specific SCF as a predicate for promulgating NSPS was 
foreclosed by ``the plain language of'' section 111--noting that this 
interpretation ignored the distinction between the text of section 111 
and that of other CAA provisions which do explicitly require a 
pollutant-specific cause-or-contribution finding. Id. at 10. Moreover, 
the Report added, ``[g]iven that the statute is not ambiguous, the EPA 
cannot interpret section 111 to authorize the EPA to exercise 
discretion to require . . . a pollutant-specific SCF as a predicate for 
promulgating a [NSPS] for the pollutant.'' Id. at 10. The Report went 
on to note several other supports for its statutory interpretation, 
including the legislative history of section 111. Id. at 10-11.
    The Senate Statement took the same approach, stating: ``we do not 
intend that section 111 of [the] CAA requires EPA to make a pollutant-
specific

[[Page 63151]]

significant contribution finding before regulating emissions of a new 
pollutant from a listed source category. . . .'' Senate Statement at 
S2283.\158\
---------------------------------------------------------------------------

    \158\ Both the House Report and the Senate Statement recognized 
that EPA could, if it chose to, make a finding that a particular 
pollutant contributes significantly to dangerous air pollution, in 
order, for example, to inform the public about the risks of a 
pollutant. House Report at 10, Senate Statement at S2283. However, 
the House Report made clear that ``it is the rational basis 
determination as to the risk a pollutant poses to endangerment of 
human health or welfare [and not any such SCF] that remains the 
statutory basis for the EPA's action.'' House Report at 10.
---------------------------------------------------------------------------

    The House Report also expressly disapproved of the 2020 Policy 
Rule's interpretation of section 111 to require that the SCF must be 
based on some ``identif[ied] standard or established set of criteria,'' 
and not the facts-and-circumstances approach that EPA has used in 
making that finding for the source category. House Report at 10-11; see 
2020 Policy Rule at 57038. The Report stated, ``[i]t is fully 
appropriate for EPA to exercise its discretion to employ a facts-and-
circumstances approach, particularly in light of the wide range of 
source categories and the air pollutants they emit that EPA must 
regulate under section 111.'' House Report at 11.
    Finally, in reinstating the methane regulations, the legislative 
history for the CRA resolution clearly expressed the intent that the 
EPA proceed with regulation of existing sources. The House Report was 
explicit in this regard, stating that ``[p]assage of the resolution of 
disapproval indicates Congress' support and desire to immediately 
reinstate . . . EPA's statutory obligation to regulate existing oil and 
natural gas sources under [CAA] section 111(d).'' House Report at 3; 
see id. at 11-12. The report added that upon enactment of the 
resolution of disapproval, ``the Committee strongly encourages the EPA 
to take swift action to . . . fulfill its statutory obligation to issue 
existing source guidelines under [CAA] section 111(d).'' Id. The Senate 
Statement was substantially similar. Senate Statement at S2283 (``By 
adopting this resolution of disapproval, it is our view that Congress 
reaffirms that the CAA requires EPA to act to protect Americans from 
sources of climate pollution like methane, which endangers the public's 
health and welfare. . . . [W]e intend that [CAA] section 111 . . . 
obligates and provides EPA with the legal authority to regulate 
existing sources of methane emissions in [the Crude Oil and Natural Gas 
source category].'').

B. Effect of Congress's Disapproval of the 2020 Policy Rule

    Under the CRA, the disapproved 2020 Policy Rule is ``treated as 
though [it] had never taken effect.'' 5 U.S.C. 801(f). As a result, the 
preceding regulation, the 2016 NSPS OOOOa rule, was automatically 
reinstated, and treated as though it had never been revised by the 2020 
Policy Rule. Moreover, the CRA bars EPA from promulgating ``a new rule 
that is substantially the same as'' a disapproved rule. 5 U.S.C. 
801(b)(2), for example, a rule that deregulates methane emissions from 
the production and processing sectors or deregulates the transmission 
and storage sector entirely.
    The legislative history of the CRA gives further content to 
Congress's disapproval and the bar on substantially similar rulemaking. 
The legislative history rejected the EPA's statutory interpretations of 
section 111 in the 2020 Policy Rule and endorsed the legal 
interpretations contained in the 2016 NSPS OOOOa rule. Specifically, 
Congress expressed its intent that the transmission and storage segment 
be included in the source category, that sources in that segment remain 
subject to NSPS, and that all oil and gas sources be subject to NSPS 
for methane emissions.\159\
---------------------------------------------------------------------------

    \159\ See generally ``Federal-State Unemployment Compensation 
Program; Establishing Appropriate Occupations for Drug Testing of 
Unemployment Compensation Applicants Under the Middle-Class Tax 
Relief and Job Creation Act of 2012: Final Rule,'' 84 FR 53037, 
53083 (Oct. 4, 2019) (citing legislative history of CRA resolution 
disapproving prior rule in explaining scope of new rule).
---------------------------------------------------------------------------

    The EPA is now proceeding to propose additional requirements to 
reduce emissions from oil and gas sources, consistent with the 
statutory factors the EPA is required to consider under section 111 and 
with section 111's overarching purpose of protecting against pollution 
that endangers health and welfare. While the reinstatement of the 2016 
Rule through the CRA joint resolution of disapproval provides the 
predicate for this action, the EPA notes that, for the reasons 
discussed next, the EPA would reject the positions concerning legal 
interpretations taken in the 2020 Policy Rule and reaffirm the 
positions the Agency took in the 2016 Rule even absent the CRA 
resolution. The EPA provides this information for the purposes of 
informing the public and is not re-opening these positions for comment.

C. Affirming the Legal Interpretations in the 2016 NSPS OOOOa Rule

    The Agency has reviewed all of the information and analyses in the 
2016 NSPS OOOOa and 2020 Policy Rule, and fully reaffirms the positions 
it took in the 2016 Rule and rejects the positions taken in the 2020 
Policy Rule.\160\ For this rulemaking, the EPA has reviewed its prior 
actions, along with newly available information, including recent 
information concerning the dangers posed by climate change and the 
impact of methane emissions, as described in section III above. Based 
on this review, the EPA affirms the statutory interpretations 
underlying the 2016 Rule and rejects the different interpretations 
informing the congressionally voided 2020 Policy Rule. This section 
explains the EPA's views. These views are confirmed by Congress's 
reasoning in the legislative history of the CRA resolution and so, for 
convenience, this section occasionally refers to that legislative 
history.
---------------------------------------------------------------------------

    \160\ Under F.C.C. v. Fox Television Stations, Inc., 556 U.S. 
502 (2009), an agency may revise its policy, but must demonstrate 
that the new policy is permissible under the statute and is 
supported by good reasons, taking into account the record of the 
previous rule. To the extent that this standard applies in this 
action--where Congress has disapproved the 2020 Policy Rule--the EPA 
believes the explanations provided here satisfy the standard.
---------------------------------------------------------------------------

    In particular, the EPA reaffirms that the Crude Oil and Natural Gas 
Source Category appropriately includes the transmission and storage 
segment, along with the production and processing segments. The EPA has 
broad discretion in determining the scope of the source category, and 
the 2016 Rule correctly identified the most important aspect of the 
industry, which is the interrelatedness of the segments and their 
common purpose in completing the multi-step process to prepare natural 
gas for marketing. 81 FR 35832, June 3, 2016. The 2020 Policy Rule's 
objection that the chemical composition of natural gas changes as it 
moves from the production and processing segments to the transmission 
and storage segment, 85 FR 57028, September 14, 2020, misses the mark 
because in every segment methane predominates and the refining of 
natural gas in the processing segment, which is what changes its 
chemical composition, is appropriately viewed simply as one of the 
steps in the marketing of the gas. Further, while it is true that some 
of the equipment in each segment differs from the equipment in the 
other segments, as the 2020 Policy Rule pointed out, 85 FR 57029 
(September 14, 2020), that too simply results from the fact that the 
segments represent different steps in the process of preparing natural 
gas for marketing. The more salient fact is that most of the polluting 
equipment, such as storage

[[Page 63152]]

vessels, pneumatic pumps, and compressors, are found throughout the 
segments and emit the same pollutants that can be controlled by the 
same techniques and technologies, 81 FR 35832 (June 3, 2016), 
underscoring the interrelated functionality of the segments and the 
appropriateness of regulating them together as part of a single source 
category. The scope of the source category as defined in 2016, and 
proposed to be affirmed in this rule, is well within the reasonable 
bounds of the EPA's past practice in defining source categories, which 
sometimes even contain sources that are located in multiple distinct 
industries. See 40 CFR part 60, subpart Db (industrial-commercial-
institutional steam generating units), 40 CFR part 60, subpart IIII 
(stationary compression ignition internal combustion engines). In this 
regard, the House Report correctly noted that ``even the presence of 
large distinctions in equipment type and emissions profile across two 
segments would not necessarily preclude EPA from regulating those 
segments as a single source category, so long as the EPA could identify 
some meaningful relationship between them,'' House Report at 7, as the 
EPA did in the 2016 Rule. Thus, the 2020 Policy Rule failed to 
articulate appropriate reasons to change the scope of the source 
category from what the EPA determined in the 2016 Rule. Having properly 
identified the scope of the source category as including the 
transmission and storage segment in the 2016 Rule, the EPA lawfully 
promulgated NSPS for sources in that segment.
    The EPA also affirms that the 2016 Rule established an appropriate 
basis for promulgating methane NSPS from oil and gas sources, and that 
the 2020 Policy Rule erred on all grounds in rescinding the methane 
NSPS. The importance of taking action at this time, in accordance with 
the requirements of CAA section 111, to reduce the enormous amount of 
methane emissions from oil and gas sources, in light of the impacts on 
the climate of this pollution, cannot be overstated. As stated in 
section I, the Oil and Natural Gas Industry is the largest industrial 
emitter of methane in the U.S. Human emissions of methane, a potent 
GHG, are responsible for about one third of the warming due to well-
mixed GHGs, the second most important human warming agent after carbon 
dioxide. According to the IPCC, strong, rapid, and sustained methane 
reductions are critical to reducing near-term disruption of the climate 
system and a vital complement to CO2 reductions critical in 
limiting the long-term extent of climate change and its destructive 
impacts.\161\ The EPA previously determined, in the 2016 NSPS OOOOa 
rule, both that it had a rational basis to regulate methane emissions 
from the source category, and, in the alternative, that methane 
emissions from the Crude Oil and Natural Gas Source Category, 
contribute significantly to dangerous air pollution. 81 FR 35842-43, 
(June 3, 2016). The EPA is not reopening those determinations for 
comment in the present rulemaking.
---------------------------------------------------------------------------

    \161\ See preamble section III for further discussion on the 
Crude Oil and Natural Gas Emissions and Climate Change, including 
discussion of the GHGs, VOCs and SO2 Emissions on Public 
Health and Welfare.
---------------------------------------------------------------------------

    Contrary to the statements in the 2020 Policy Rule, the methane 
NSPS promulgated in the 2016 Rule cannot be said to be redundant with 
the VOC NSPS and therefore unnecessary. The large contribution of 
methane emissions from the source category to dangerous air pollution 
driving the grave and growing threat of climate change means that, in 
the agency's judgment, it would be highly irresponsible and also 
arbitrary and capricious under CAA section 307(d)(9)(A) for the EPA to 
decline to promulgate NSPS for methane emissions from the source 
category. See American Electric Power, 564 U.S. at 426-27. The fact 
that the EPA designed the methane NSPS so that sources could comply 
with them efficiently, through the same actions that the sources needed 
to take to comply with the VOC NSPS, did not thereby create redundancy. 
Further, the fact that methane NSPS but not the VOC NSPS trigger the 
regulatory requirements for existing sources makes clear that the two 
sets of requirements are not redundant. Indeed, if EPA had only 
regulated VOCs, it would only have been authorized to regulate new and 
modified sources, which comprise a small subset of polluting sources. 
By contrast, because the 2016 Rule also regulated methane, EPA was 
authorized and obligated to regulate hundreds of thousands of 
additional ``existing'' sources that comprise the vast majority of 
polluting sources. Accordingly, methane regulation was not 
``redundant'' of VOC regulation. The 2020 Policy Rule's contrary 
position was based on a misinterpretation of CAA section 111 which 
overlooked that the provision integrates requirements for new and 
existing sources. See Nat'l Lime Ass'n v. EPA, 627 F.2d 416, 433 n.48 
(D.C. Cir. 1980) (CAA section 111(b)(1)(A) listing of a source category 
is based on emissions from new and existing sources).
    The EPA also reaffirms the 2016 Rule's statutory interpretation 
that the EPA is authorized to promulgate a NSPS for an air pollutant 
under CAA section 111(b)(1)(B) in a situation in which the EPA has 
previously determined that the source category causes or contributes 
significantly to dangerous air pollution and where the EPA has a 
rational basis for regulating the particular air pollutant in question 
that is emitted by the source category. 81 FR 35842 (June 3, 2016). The 
2016 Rule noted the precedent in prior agency actions for the position 
that--following the listing of a source category--the EPA need provide 
only a rational basis for its exercise of discretion for which 
pollutants to regulate under section 111(b)(1)(B). See id. (citing 
National Lime Assoc. v. EPA, 627 F.2d 416, 426 & n.27 (D.C. Cir. 1980) 
(court discussed, but did not review, the EPA's reasons for not 
promulgating standards for NOX, SO2, and CO from 
lime plants). In addition, the Supreme Court in American Electric Power 
provided support for the rational basis statutory interpretation. 564 
U.S. at 426-27 (``EPA [could] decline to regulate carbon-dioxide 
emissions altogether at the conclusion of its . . . [CAA section 111] 
rulemaking,'' and such a decision ``would not escape judicial review,'' 
under the ``arbitrary and capricious'' standard of section 
307(d)(9)(A)). As the House Report noted, the EPA's rational basis 
interpretation ``is fully consistent with the provision[s] of section 
111 and the section 307(d)(9) `arbitrary and capricious' standard.'' 
House Report at 9.
    The 2020 Policy Rule correctly noted that the CAA section 
111(b)(1)(B) requirement that the EPA ``shall promulgate . . . 
standards [of performance]'' for air pollutants, coupled with the CAA 
section 111(a)(1) definition for ``standard of performance'' as, in 
relevant part, a ``standard for emissions of air pollutants,'' does not 
by its terms require that EPA promulgate NSPS for every air pollutant 
from the source category. But the rule erred in seeking to graft the 
CAA section 111(b)(1)(A) requirement for a SCF into CAA section 
111(b)(1)(B). The language of CAA section 111(b)(1)(A) is clear: It 
requires the EPA Administrator to ``include a category of sources in 
[the list for regulation] if in his judgment it causes, or contributes 
to, air pollution which may reasonably be anticipated to endanger 
public health or welfare.'' (Emphasis added.) Congress thus specified 
that the required SCF is made

[[Page 63153]]

on a category basis, not a pollutant-specific basis, and that once that 
finding is made (as it was for the Crude Oil and Natural Gas source 
category in 1979), the EPA may establish standards for pollutants 
emitted by the source category. In determining for which air pollutants 
to promulgate standards of performance, the EPA must act rationally, 
which, as noted above, essentially must ensure that the action does not 
fail the ``arbitrary and capricious'' standard under CAA section 
307(d)(9)(A). The 2020 Policy Rule's objections to the rational basis 
standard on grounds that is ``vague and not guided by any statutory 
criteria,'' 85 FR 57034 (September 14, 2020), is incorrect. In making a 
rational basis determination, the EPA has considered the amount of the 
air pollutant emitted by the source category, both in absolute terms 
and by drawing comparisons, as well as the availability of control 
technologies. See National Lime Assoc. v. EPA, 627 F.2d 416, 426 & n.27 
(D.C. Cir. 1980) (discussing EPA's reasons for not promulgating 
standards for NOX, SO2 and CO from lime plants); 
80 FR 64510, 64530 (October 23, 2015) (rational basis determination for 
GHGs from fossil fuel-fired electricity generating power plants); 73 FR 
35838, 35859-60 (June 24, 2008) (providing reasons why the EPA was not 
promulgating GHG standards for petroleum refineries). Courts routinely 
review rules under the ``arbitrary and capricious'' standard, as noted 
in the House Report, at 11.
    When the EPA is required to make an endangerment finding, the EPA 
also affirms that that finding should be made in consideration of the 
particular facts and circumstances, not a predetermined threshold. 
Accordingly, the EPA rejects the 2020 Policy Rule's position to the 
contrary. Section 111(b)(1)(A) of the CAA does not require that the SCF 
for the source category be based on ``established criteria'' or 
``standard or threshold.'' See Coal. for Responsible Regulation, Inc. 
v. EPA, 684 F.3d 102, 122-23 (D.C. Cir. 2012) (``the inquiry [into 
whether an air pollutant endangers] necessarily entails a case-by-case, 
sliding-scale approach. . . . EPA need not establish a minimum 
threshold of risk or harm before determining whether an air pollutant 
endangers''). During the 50 years that it has made listing decisions, 
the EPA has always relied on the individual facts and circumstances. 
See Alaska Dep't of Envtl. Conservation, 540 U.S. 461, 487 (2004) 
(explaining, in a case under the CAA, ``[w]e normally accord particular 
deference to an agency interpretation of longstanding duration'' 
(internal quotation marks omitted) (citing Barnhart v. Walton, 535 U.S. 
212, 220 (2002)). This approach is appropriate because Congress 
intended that CAA section 111 apply to a wide range of source 
categories and pollutants, from wood heaters to emergency backup 
engines to petroleum refineries. In that context, it reasonable to 
interpret section 111 to allow EPA the discretion to determine how best 
to assess significant contribution and endangerment based on the 
individual circumstances of each source category. On this point, as 
well, the EPA is in full agreement with the statements in the House 
Report. House Report at 9-10.
    Finally, under CAA section 111(d)(1), once the EPA promulgates NSPS 
for certain air pollutants, including GHGs, the EPA is required to 
promulgate regulations, which the EPA terms EG, 40 CFR 60.22a, that in 
turn require States to promulgate standards of performance for existing 
sources of those air pollutants. The EPA agrees with the House Report 
and Senate statement that it is imperative to regulate methane 
emissions from the existing oil and gas sources that comprise the vast 
majority of polluting sources expeditiously under the authority of CAA 
section 111(d) and is proceeding with the process to do so in this 
rulemaking by publishing proposed EG. See section III.B.2. In 2019, the 
GHGI estimates for oil and natural gas production, and natural gas 
processing and transmission and storage segments that methane emissions 
equate to 182 MMT CO2 Eq.\162\ In the U.S. the EPA has 
identified over 15,000 oil and gas owners and operators, around 1 
million producing onshore oil and gas wells, about 5,000 gathering and 
boosting facilities, over 650 natural gas processing facilities, and 
about 1,400 transmission compression facilities.
---------------------------------------------------------------------------

    \162\ The 100-year GWP value of 25 for methane indicates that 
one ton of methane has approximately as much climate impact over a 
100-year period as 25 tons of CO2. The most recent IPCC 
AR6 assessment has estimated a slightly larger 100-year GWP of 
methane of almost 30 (specifically, either 27.2 or 29.8 depending on 
whether the value includes the CO2 produced by the 
oxidation of methane in the atmosphere). As mentioned earlier, 
because methane has a shorter lifetime than CO2, the 
emissions of a ton of methane will have more impact earlier in the 
100-year timespan and less impact later in the 100-year timespan 
relative to the emissions of a 100-year GWP-equivalent quantity of 
CO2. See preamble section III for further discussion on 
the Crude Oil and Natural Gas Emissions and Climate Change, 
including discussion of the GHGs, VOCs and SO2 Emissions 
on Public Health and Welfare.
---------------------------------------------------------------------------

    Some stakeholders have raised issues concerning the scope of 
pollutants subject to CAA section 111(d) by arguing that the exclusion 
in CAA section 111(d) for HAP covers not only those pollutants listed 
for regulation under CAA section 112, but also precludes the EPA from 
regulating a source category under CAA section 111(d) for any pollutant 
if that source category has been regulated under CAA section 112. The 
EPA agrees with its longstanding legal interpretation spanning multiple 
Administrations that the 111(d) exclusion does not preclude the agency 
from regulating a non-HAP pollutant from a source category under 
section 111(d) even if that source category is regulated under section 
112. See American Lung Ass'n v. EPA, 980 F.3d 914, 980 (D.C. Cir. 2019) 
(referring to ``EPA's three-decade-old . . . reading of the statutory 
amendments''), petition for cert. pending No. 20-1530 (filed April 29, 
2021); 70 FR 15994, 16029 (March 29, 2005) (Clean Air Mercury Rule); 80 
FR 64662, 64710 (Oct. 23, 2015) (Clean Power Plan); 84 FR 32520 (July 
8, 2019) (Affordable Clean Energy Rule). The House Report agreed with 
this interpretation, noting that the contrary position is flawed 
because it ignores the overall statutory structure that Congress 
created in the CAA and would create regulatory gaps in which the EPA 
would not be able to regulate existing sources for some pollutants 
(such as methane) under CAA section 111(d) if those sources (but not 
pollutants) were already regulated for different pollutants under CAA 
section 112. House Report at 11-12. Moreover, the D.C. Circuit recently 
considered this precise issue and held that the EPA may both regulate a 
source category for HAP under CAA section 112 and regulate that same 
source category for different pollutants under CAA section 111(d). Am. 
Lung Assoc., 985 F.3d at 977-988. Accordingly, both Congress and the 
court have come to the same conclusion after reviewing the statutory 
language, a conclusion that is aligned with the EPA's longstanding 
position. We therefore proceed in the proposal to propose EGs for 
existing sources in the oil and gas source category.

IX. Overview of Control and Control Costs

A. Control of Methane and VOC Emissions in the Crude Oil and Natural 
Gas Source Category--Overview

    As described in this action, the EPA reviewed the standards in the 
2016 NSPS OOOOa pursuant to CAA section 111(b)(1)(B). Based on this 
review, the EPA is proposing revisions to the standards for a number of 
affected facilities to reflect the updated BSER for those affected 
facilities. Where our analyses show that the BSER for an

[[Page 63154]]

affected facility remains the same, the EPA is proposing to retain the 
current standard for that affected facility. In addition to the actions 
on the standards in the 2016 NSPS OOOOa described in this section, the 
EPA is proposing standards for GHGs (in the form of limitation on 
methane) and VOCs for a number of new sources that are currently 
unregulated. The proposed NSPS OOOOb would apply to new, modified, and 
reconstructed emission sources across the Crude Oil and Natural Gas 
source category for which construction, reconstruction, or modification 
is commenced after November 15, 2021.
    Further, pursuant to CAA section 111(d), the EPA is proposing EG, 
which include presumptive standards for GHGs (in the form of 
limitations on methane) (designated pollutant), for certain existing 
emission sources across the Crude Oil and Natural Gas source category 
in the proposed EG OOOOc. While the proposed requirements in NSPS OOOOb 
would apply directly to new sources, the proposed requirements in EG 
OOOOc are for States to use in the development of plans that establish 
standards of performance that will apply to existing sources 
(designated facilities).

B. How does EPA evaluate control costs in this action?

    Section 111 of the CAA requires that the EPA consider a number of 
factors, including cost, in determining ``the best system of emission 
reduction . . . adequately demonstrated.'' CAA section 111(a)(1). The 
D.C. Circuit has long recognized that ``[CAA] section 111 does not set 
forth the weight that [ ] should [be] assigned to each of these 
factors;'' therefore, ``[the court has] granted the agency a great 
degree of discretion in balancing them.'' Lignite Energy Council v. 
EPA, 198 F.3d 930, 933 (D.C. Cir. 1999) (``Lignite Energy Council''). 
In Essex Chemical Corp. v. Ruckelshaus, 486 F.2d 427 (D.C. Cir. 1973) 
(``Essex Chemical''), the court noted that ``it is not unlikely that 
the industry and the EPA will disagree on the economic costs of various 
control techniques'' and that it ``has no desire or special ability to 
settle such a dispute.'' Id. at 437. Rather, the court focused its 
review on ``whether the standards as set are the result of reasoned 
decision-making.'' Id. at 434. A standard that ``is the result of the 
exercise of reasoned discretion by the Administrator [ ] cannot be 
upset by this Court.'' Id. at 437.
    As noted, CAA section 111 requires that the EPA consider cost in 
determining such system (i.e., ``BSER''), but it does not prescribe any 
criteria for such consideration. The courts have recognized that the 
EPA has ``considerable discretion under [CAA] section 111,'' Lignite 
Energy Council, 198 F.3d at 933, on how it considers cost under CAA 
section 111(a)(1). For example, in Essex Chemical, the D.C. Circuit 
stated that to be ``adequately demonstrated,'' the system must be 
``reasonably reliable, reasonably efficient, and . . . reasonably 
expected to serve the interests of pollution control without becoming 
exorbitantly costly in an economic or environmental way.'' 486 F.2d at 
433. The court has reiterated this limit in subsequent case law, 
including Lignite Energy Council, in which it stated: ``EPA's choice 
will be sustained unless the environmental or economic costs of using 
the technology are exorbitant.'' 198 F.3d at 933. In Portland Cement 
Association v. Train, the court elaborated by explaining that the 
inquiry is whether the costs of the standard are ``greater than the 
industry could bear and survive.'' \163\ 513 F.2d 506, 508 (D.C. Cir. 
1975). In Sierra Club v. Costle, the court provided a substantially 
similar formulation of the cost factor: ``EPA concluded that the 
Electric Utilities' forecasted cost was not excessive and did not make 
the cost of compliance with the standard unreasonable. This is a 
judgment call with which we are not inclined to quarrel.'' 657 F.2d 
298, 343 (D.C. Cir. 1981). We believe that these various formulations 
of the cost factor--``exorbitant,'' ``greater than the industry could 
bear and survive,'' ``excessive,'' and ``unreasonable''--are 
synonymous; the D.C. Circuit has made no attempt to distinguish among 
them. For convenience, in this rulemaking, we will use the term 
``reasonable'' to describe that our evaluation of costs is well within 
the boundaries established by this case law.
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    \163\ The 1970 Senate Committee Report on the Clean Air Act 
stated: ``The implicit consideration of economic factors in 
determining whether technology is `available' should not affect the 
usefulness of this section. The overriding purpose of this section 
would be to prevent new air pollution problems, and toward that end, 
maximum feasible control of new sources at the time of their 
construction is seen by the committee as the most effective and, in 
the long run, the least expensive approach.'' S. Comm. Rep. No. 91-
1196 at 16.
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    In evaluating whether the cost of a control is reasonable, the EPA 
considers various costs associated with such control, including capital 
costs and operating costs, and the emission reductions that the control 
can achieve. As discussed further below, the agency considers these 
costs in the context of the industry's overall capital expenditures and 
revenues. Cost-effectiveness analysis is also a useful metric, and a 
means of evaluating whether a given control achieves emission reduction 
at a reasonable cost. A cost-effectiveness analysis also allows 
comparisons of relative costs and outcomes (effects) of two or more 
options. In general, cost-effectiveness is a measure of the outcomes 
produced by resources spent. In the context of air pollution control 
options, cost-effectiveness typically refers to the annualized cost of 
implementing an air pollution control option divided by the amount of 
pollutant reductions realized annually. A cost-effectiveness analysis 
is not intended to constitute or approximate a benefit-cost analysis in 
which monetized benefits are compared to costs, but rather provides a 
metric to compare the relative cost and emissions impacts of various 
control options.
    The estimation and interpretation of cost-effectiveness values is 
relatively straightforward when an abatement measure is implemented for 
the purpose of controlling a single pollutant, such as for the controls 
included as presumptive standards in the proposed EG OOOOc to address 
methane emissions from existing sources in the Crude Oil and Natural 
Gas source category. In other circumstances, air pollution reduction 
programs require reductions in emissions of multiple pollutants, as 
with the NSPS for the Crude Oil and Natural Gas source category, which 
regulates both GHG and VOC. In such cases, multipollutant controls 
(controls that achieve reductions of both pollutants through the same 
techniques and technologies) may be employed, and consequently, there 
is a need for determining cost-effectiveness for a control option 
across multiple pollutants (or classes of multiple pollutants).
    During the rulemaking for NSPS OOOOa, we evaluated a number of 
approaches for considering the cost-effectiveness of the available 
multipollutant controls for reducing both methane and VOC emissions. 
See 80 FR 56593, 56616 (September 18, 2015). In that rulemaking, we 
used two approaches for considering the cost-effectiveness of control 
options that reduce both VOC and methane emissions; we are proposing to 
use these same two cost-effectiveness approaches, along with other 
factors discussed further below, in considering the cost of requiring 
control for the proposed NSPS OOOOb. One approach, which we refer to as 
the ``single pollutant cost-effectiveness approach,'' assigns all costs 
to the emission reduction of one pollutant and zero to all other 
concurrent reductions. If the cost is reasonable for reducing any of 
the

[[Page 63155]]

targeted pollutants alone, the cost of such control is clearly 
reasonable for the concurrent emission reduction of all the other 
regulated pollutants because they are being reduced at no additional 
cost. While this approach assigns all costs to only a portion of the 
emission reduction and thus may overstate the cost for that assigned 
portion, it does not overstate the overall cost. Instead, it 
acknowledges that the reductions of the other regulated pollutant are 
intended as opposed to incidental. This approach is simple and 
straightforward in application: If the multipollutant control is cost 
effective for reducing emissions of either of the targeted pollutants, 
it is clearly cost effective for reducing all other targeted emissions 
that are being achieved simultaneously.
    A second approach, which we term for the purpose of this rulemaking 
a ``multipollutant cost-effectiveness approach,'' apportions the 
annualized cost across the pollutant reductions addressed by the 
control option in proportion to the relative percentage reduction of 
each pollutant controlled. In the case of the Crude Oil and Natural Gas 
source category, both methane and VOC are reduced in equal proportions, 
relative to their respective baselines by the multipollutant control 
option (i.e., where control is 95 percent reduction, methane and VOC 
are both simultaneously reduced by 95 percent by the multipollutant 
control). As a result, under the multipollutant cost-effectiveness 
approach, half of the control costs are allocated to methane and the 
other half to VOC. Under this approach, control is cost effective if it 
is cost effective for both VOC and methane.
    We believe that both the single pollutant and multipollutant cost-
effectiveness approaches discussed above are appropriate for assessing 
the reasonableness of the multipollutant controls considered in this 
action for new sources. As such, in the individual BSER analyses in 
section XII below, if a device is cost-effective under either of these 
two approaches, we find it to be cost-effective. The EPA has considered 
similar approaches in the past when considering multiple pollutants 
that are controlled by a given control option.\164\ The EPA recognizes, 
however, not all situations where multipollutant controls are applied 
are the same, and that other types of approaches might be appropriate 
in other instances.
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    \164\ See, e.g., 73 FR 64079-64083 and EPA Document I.D. EPA-HQ-
OAR-2004-0022-0622, EPA-HQ-OAR-2004-0022-0447, EPA-HQ-OAR- 2004-
0022-0448.
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    As mentioned above, as part of its consideration of control costs 
in the individual BSER analyses in Section XII, the EPA evaluated cost-
effectiveness using the single pollutant and multipollutant cost-
effectiveness approaches. We estimated the cost-effectiveness values of 
the proposed control options using available information, including 
various studies, information submitted in previous rulemakings from the 
affected industry, and information provided by small businesses. The 
EPA provides the cost effectiveness estimates for reducing VOC and 
methane emissions for various control options considered in section 
XII. As discussed in that section, the EPA finds cost-effectiveness 
values up to $5,540/ton of VOC reduction to be reasonable for controls 
that we have identified as BSER in this proposal. These VOC values are 
within the range of what the EPA has historically considered to 
represent cost effective controls for the reduction of VOC emissions, 
including in the 2016 NSPS, based on the Agency's long history of 
regulating a wide range of industries. With respect to methane, the EPA 
finds the cost-effectiveness values up to $1,800/ton of methane 
reduction to be reasonable for controls that we have identified as BSER 
in this proposal. Unlike VOC, the EPA does not have a long regulatory 
history to draw upon in assessing the cost effectiveness of controlling 
methane, as the 2016 NSPS OOOOa was the first national standard for 
reducing methane emissions. However, as explained below, the EPA has 
previously determined that methane cost-effectiveness values for the 
controls identified as BSER for the 2016 NSPS OOOOa, which range up to 
$2,185/ton of methane reduction, represent reasonable costs for the 
industry as a whole to bear; and because the cost-effectiveness 
estimates for the proposed standards in this action are comparable to 
the cost-effectiveness values estimated for the controls that served as 
the basis (i.e., BSER) for the standards in the 2016 NSPS OOOOa, we 
consider the proposed standards to also be cost effective and 
reasonable.
    The BSER determinations from the 2016 NSPS OOOOa also support the 
EPA's conclusion that the cost-effectiveness values associated with the 
proposed standards in this action are reasonable. As mentioned above, 
for 2016 NSPS OOOOa, the highest estimate that the EPA considered cost 
effective for methane reduction was $2,185/ton, which was the estimate 
for converting a natural gas driven diaphragm pump to an instrument air 
pump at a gas processing plant. 165 166 80 FR 56627; see 
also, NSPS OOOOa Final TSD at 93, Table 6-7. The EPA estimated that the 
cost-effectiveness of this option, a common practice at gas processing 
plants, could be up to $2,185/ton of methane reduction under the single 
pollutant cost-effectiveness approach and $1,093/ton under the 
multipollutant cost effectiveness approach; the EPA found ``the control 
to be cost effective under either approach.'' Id. Accordingly, the EPA 
finalized requirements in the 2016 NSPS OOOOa that require zero 
emissions from diaphragm pumps at gas processing plants, consistent 
with the Agency's BSER determination.
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    \165\ As discussed in section X.A, the EPA incorrectly stated in 
the 2020 Technical Rule that $738/ton of methane reduction was the 
highest cost-effectiveness value that the EPA determined to be 
reasonable for methane reduction in the 2016 NSPS OOOOa.
    \166\ While in that rulemaking the EPA found quarterly 
monitoring of fugitive emissions at well sites not cost effective at 
$1,960/ton of methane reduced using the single pollutant approach 
(and $980 using the multi-pollutant approach), the EPA emphasized 
that this conclusion was not intended to ``preclude the EPA from 
taking a different approach in the future including requiring more 
frequent monitoring (e.g., quarterly).'' 81 FR 35855-6 referencing 
Background Technical Support Document for the New Source Performance 
Standards 40 CFR part 60 subpart OOOOa (May 2016), at 49, Table 4-11 
and 52, Table 4-14. Further, several states have issued regulations 
and industry has voluntarily taken steps to reduce emissions. This 
combined with greater knowledge and understanding of the industry 
leads us to find these values cost-effective. As discussed in this 
section IX.B, cost-effectiveness is one--not the only--factor in 
EPA's consideration of control costs. In fact, in this action, the 
EPA is proposing different monitoring frequencies based on well site 
baseline emissions, even though the EPA found quarterly monitoring 
to be cost effective for all well sites. Please see section XII.A 
for a detailed discussion on this proposal.
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    The 2016 NSPS OOOOa also requires 95 percent methane and VOC 
emission reduction from wet-seal centrifugal compressors. The BSER for 
this standard was capturing and routing the emissions to a control 
combustion device, a widely used control in the oil and gas sector for 
reducing emissions from storage vessels and pumps, in addition to 
centrifugal compressors. 80 FR 56620. The EPA estimated cost-
effectiveness values of up to $1,093/ton of methane reduction for this 
option. See NSPS OOOOa Final TSD at 114, Table 7-9. With respect to 
other controls identified as BSER in the 2016 NSPS OOOOa, their cost-
effectiveness estimates were comparable to or well below the estimates 
from the 2016 NSPS OOOOa rulemaking discussed above. In light of this, 
and because sources have been complying with the 2016 NSPS OOOOa for 
years, we believe that the cost-effectiveness values for the controls

[[Page 63156]]

identified as BSER for the 2016 NSPS OOOOa, which range up to $2,185/
ton of methane reduction, represent reasonable, rather than excessive, 
costs for the industry as a whole to bear. As shown in the individual 
BSER analyses in Section XII and the NSPS OOOOb and EG OOOOc TSD for 
this proposal, the cost-effectiveness values for the proposed standards 
in this action are comparable to the cost-effectiveness values for the 
standards in NSPS OOOOa. We, therefore, similarly consider the cost-
effectiveness values for the proposed standards to be reasonable. That 
the proposed standards reflect the kinds of controls that many 
companies and sources around the country are already implementing 
underscore the reasonableness of these control measures.
    In addition to evaluating the annual average cost-effectiveness of 
a control option, the EPA also considers the incremental costs 
associated with increasing the stringency of the standards from one 
level of control to another level of control that achieves more 
emission reductions. The incremental cost of control provides insight 
into how much it costs to achieve the next increment of emission 
reductions through application of each increasingly stringent control 
options, and thus is a useful tool for distinguishing among the effects 
of more and less stringent control options. For example, during the 
rulemaking for the 2012 NSPS OOOO, the EPA considered the incremental 
cost effectiveness of changing the originally promulgated standards for 
leaks at gas processing plants, which were based on NSPS subpart VV, to 
the more stringent NSPS subpart VVa-level program. See 76 FR 52738, 
52755 (August 23, 2011). The EPA generally finds the incremental cost-
effectiveness to be reasonable if it is consistent with the costs that 
the Agency considers reasonable in its evaluation of annual average 
cost-effectiveness.
    As shown in the NSPS OOOOb and EG OOOOc TSD for this action, the 
EPA estimated control costs both with and without savings from 
recovered gas that would otherwise be emitted. When determining the 
overall costs of implementation of the control technology and the 
associated cost-effectiveness, the EPA reasonably takes into account 
any expected revenues from the sale of natural gas product that would 
be realized as a result of avoided emissions that result from 
implementation of a control. Such a sale would offset regulatory costs 
and so should be included to accurately assess the overall costs and 
the cost-effectiveness of the standard. In our analysis we consider any 
natural gas that is either recovered or that is not emitted as a result 
of a control option as being ``saved.'' We estimate that one thousand 
standard cubic feet (Mcf) of natural gas is valued at $3.13 per 
Mcf.\167\ Our cost analysis then applies the monetary value of the 
saved natural gas as an offset to the control cost.\168\ This offset 
applies where, in our estimation, the monetary savings of the natural 
gas saved can be realized by the affected facility owner or operator 
and not where the owner or operator does not own the gas and would not 
likely realize the monetary value of the natural gas saved (e.g., 
transmission stations and storage facilities). Detailed discussions of 
these assumptions are presented in section 2 of the RIA associated with 
this action, which is in the docket.
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    \167\ This value reflects the forecasted Henry Hub price for 
2022 from: U.S. Energy Information Administration. Short-Term Energy 
Outlook. https://www.eia.gov/outlooks/steo/archives/may21.pdf. 
Release Date: May 11, 2021.
    \168\ While the EPA presents cost-effectiveness with and without 
cost savings, the BSER is determined based on the cost-effectiveness 
without cost savings in all cases.
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    We also completed two additional analyses to further inform our 
determination of whether the cost of control is reasonable, similar to 
compliance cost analyses we have completed for other NSPS.\169\ First, 
we compared the capital costs that would be incurred to comply with the 
proposed standards to the industry's estimated new annual capital 
expenditures. This analysis allowed us to compare the capital costs 
that would be incurred to comply with the proposed standards to the 
level of new capital expenditures that the industry is incurring in the 
absence of the proposed standards. We then determined whether the 
capital costs appear reasonable in comparison to the industry's current 
level of capital spending. Second, we compared the annualized costs 
that would be incurred to comply with the standards to the industry's 
estimated annual revenues. This analysis allowed us to evaluate the 
annualized costs as a percentage of the revenues being generated by the 
industry.
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    \169\ For example, see our compliance cost analysis in 
``Regulatory Impact Analysis (RIA) for Residential Wood Heaters NSPS 
Revision. Final Report.'' U.S. Environmental Protection Agency, 
Office of Air Quality Planning and Standards. EPA-452/R-15-001, 
February 2015.
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    The EPA has evaluated incremental capital costs in a manner similar 
to the analyses described above in prior new source performance 
standards, and in those prior standards, the Agency's determinations 
that the costs were reasonable were upheld by the courts. For example, 
the EPA estimated that the costs for the 1971 NSPS for coal-fired 
electric utility generating units were $19 million for a 600 MW plant, 
consisting of $3.6 million for particulate matter controls, $14.4 
million for sulfur dioxide controls, and $1 million for nitrogen oxides 
controls, representing a total 15.8 percent increase in capital costs 
above the $120 million cost of the plant.\170\ See 1972 Supplemental 
Statement, 37 FR 5767, 5769 (March 21, 1972). The D.C. Circuit upheld 
the EPA's determination that the costs associated with the final 1971 
standard were reasonable, concluding that the EPA had properly taken 
costs into consideration. Essex Chemical, 486 F. 2d at 440. Similarly, 
in Portland Cement Association v. Ruckelshaus, the D.C. Circuit upheld 
the EPA's consideration of costs for a standard of performance that 
would increase capital costs by about 12 percent, although the rule was 
remanded due to an unrelated procedural issue. 486 F.2d 375, 387-88 
(D.C. Cir. 1973). Reviewing the EPA's final rule after remand, the 
court again upheld the standards and the EPA's consideration of costs, 
noting that ``[t]he industry has not shown inability to adjust itself 
in a healthy economic fashion to the end sought by the Act as 
represented by the standards prescribed.'' Portland Cement Assn. v. 
Train, 513 F. 2d at 508.
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    \170\ Assuming these costs were denominated in 1971 dollars, 
converting the costs from 1971 to 2019 dollars using the Gross 
Domestic Product-Implicit Price Deflator, the costs for the 1971 
NSPS for coal-fired electric utility generating units were $94 
million for a 600 MW plant, consisting of $18 million for 
particulate matter controls, $71 million for sulfur dioxide 
controls, and $5 million for nitrogen oxides controls, representing 
a 15.8 percent increase in capital costs above the $590 million cost 
of the plant.
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    In this action, for the capital expenditures analysis, we divide 
the nationwide capital expenditures projected to be spent to comply 
with the proposed standards by an estimate of the total sector-level 
new capital expenditures for a representative year to determine the 
percentage that the nationwide capital cost requirements under the 
proposal represent of the total capital expenditures by the sector. We 
combine the compliance-related capital costs under the proposed 
standards for the NSPS and for the presumptive standards in the 
proposed EG to analyze the potential aggregate impact of the proposal. 
The EAV of the projected compliance-related capital expenditures over 
the 2023 to 2035 period is projected to be about $510 million in 2019 
dollars. We obtained new capital

[[Page 63157]]

expenditure data for relevant NAICS codes for 2018 from the U.S. Census 
2019 Annual Capital Expenditures Survey.\171\ Estimates of new capital 
expenditures are available for 2019, but we chose to use 2018 because 
the 2019 new capital expenditure data for pipeline transportation of 
natural gas (NAICS 4862) are withheld to avoid disclosing data for 
individual enterprises, and the withholding of that NAICS causes the 
totals for 2019 to be lower than for 2018. According to these data, new 
capital expenditures for the sector in 2018 were about $155 billion in 
2019 dollars. Comparing the EAV of the projected compliance-related 
capital expenditures under the proposal with the 2018 total sector-
level new capital expenditures yields a percentage of about 0.3 
percent, which is well below the percentage increase previously upheld 
by the courts, as discussed above.
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    \171\ U.S. Census Bureau, 2019 Annual Capital Expenditures 
Survey, Table 4b. Capital Expenditures for Structures and Equipment 
for Companies With Employees by Industry: 2018 Revised, http://www.census.gov/econ/aces/index.html, accessed September 4, 2021.
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    For the comparison of compliance costs to revenues, we use the EAV 
of the projected compliance costs without and with projected revenues 
from product recovery under the proposal for the 2023 to 2035 period 
then divided the nationwide annualized costs by the annual revenues for 
the appropriate NAICS code(s) for a representative year to determine 
the percentage that the nationwide annualized costs represent of annual 
revenues. Like we do for capital expenditures, we combine the costs 
projected to be expended to comply with the standards for NSPS and the 
presumptive standards in the proposed EG to analyze the potential 
aggregate impact of the proposal. The EAV of the associated increase in 
compliance cost over the 2023 to 2035 period is projected to be about 
$1.2 billion without revenues from product recovery and about $760 
million with revenues from product recovery (in 2019 dollars). Revenue 
data for relevant NAICS codes were obtained from the U.S. Census 2017 
County Business Patterns and Economic Census, the most recent revenue 
figures available.\172\ According to these data, 2018 receipts for the 
sector were about $358 billion in 2019 dollars. Comparing the EAV of 
the projected compliance costs under the proposal with the sector-level 
receipts figure yields a percentage of about 0.3 percent without 
revenues from product recovery and about 0.2 percent with revenues from 
product recovery. More data and analysis supporting the comparison of 
capital expenditures and annualized costs projected to be incurred 
under the rule and the sector-level capital expenditures and receipts 
is presented in Chapter 15 of the TSD for this action, which is in the 
public docket.
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    \172\ 2017 County Business Patterns and Economic Census. The 
Number of Firms and Establishments, Employment, Annual Payroll, and 
Receipts by Industry and Enterprise Receipts Size: 2017, https://www.census.gov/programs-surveys/susb/data/tables.2017.html, accessed 
September 4. 2021.
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    In considering the costs of the control options evaluated in this 
action, the EPA estimated the control costs under various approaches, 
including annual average cost-effectiveness and incremental cost-
effectiveness of a given control. The EPA also performed two broad 
comparisons to consider the costs of control: First, we compared the 
projected compliance-related capital expenditures to recent sector-
level capital expenditures; second, we compared the projected total 
compliance costs to recent sector-level annual revenues. In its cost-
effectiveness analyses, the EPA recognized and took into account that 
these multi-pollutant controls reduce both VOC and methane emissions in 
equal proportions, as reflected in the single-pollutant and 
multipollutant cost effectiveness approaches. The EPA also considered 
cost saving from the natural gas recovered instead of vented due to the 
proposed controls. Based on all of the considerations described above, 
the EPA concludes that the costs of the controls that serve as the 
basis of the standards proposed in this action are reasonable. The EPA 
solicits comment on its approaches for considering control costs, as 
well as the resulting analyses and conclusions.

X. Summary of Proposed Action for NSPS OOOOa

    As described above in sections IV and VIII, the 2020 Policy Rule 
rescinded all NSPS regulating emissions of VOC and methane from sources 
in the natural gas transmission and storage segment of the Oil and 
Natural Gas Industry and NSPS regulating methane from sources in the 
industry's production and processing segments. As a result, the 2020 
Technical Rule only amended the VOC standards for the production and 
processing segments in the 2016 NSPS OOOOa, because those were the only 
standards that remained at the time that the 2020 Technical Rule was 
finalized. The 2020 Technical Rule included amendments to address a 
range of technical and implementation issues in response to 
administrative petitions for reconsideration and other issues brought 
to the EPA's attention since promulgating the 2016 NSPS. These 
included, among other issues, those associated with the implementation 
of the fugitive emissions requirements and pneumatic pump standards, 
provisions to apply for the use of an AMEL, provisions for determining 
applicability of the storage vessel standards, and modification to the 
engineer certifications. In 2018, the EPA proposed amendments to 
address these technical issues for both the methane and VOC standards 
in the 2016 NSPS OOOOa, and in some instances for sources in the 
transmission and storage segment. 83 FR 52056, October 15, 2018. 
However, because the methane standards and all standards for the 
transmission and storage segment were removed via the 2020 Policy Rule 
prior to the finalization of the 2020 Technical Rule, the final 
amendments in the 2020 Technical Rule apply only to the 2016 NSPS OOOOa 
VOC standards for the production and processing segments. Additionally, 
the 2020 Policy Rule amended the 2012 NSPS OOOO to remove the VOC 
requirements for sources in the transmission and storage segment, but 
the Technical Rule did not amend the 2012 NSPS OOOO.
    Under the CRA, a rule that is subject to a joint resolution of 
disapproval ``shall be treated as though such rule had never taken 
effect.'' 5 U.S.C. 801(f)(2). Thus, because it was disapproved under 
the CRA, the 2020 Policy Rule is treated as never having taken effect. 
As a result, the requirements in the 2012 NSPS OOOO and 2016 NSPS OOOOa 
that the 2020 Policy Rule repealed (i.e., the VOC and methane standards 
for the transmission and storage segment, as well as the methane 
standards for the production and processing segments) must be treated 
as being in effect immediately upon enactment of the joint resolution 
on June 30, 2021. Any new, reconstructed, or modified facility that 
would have been subject to the 2012 or 2016 NSPS (``affected 
facility'') but for the 2020 Policy Rule was subject to those NSPS as 
of that date. The CRA resolution did not address the 2020 Technical 
Rule; therefore, the amendments made in the 2020 Technical Rule, which 
apply only to the VOC standards for the production and processing 
segments in the 2016 NSPS OOOOa, remain in effect. As a result, sources 
in the production and processing segments are now subject to two 
different sets of standards:\173\ One

[[Page 63158]]

for methane based on the 2016 NSPS OOOOa, and one for VOC that include 
the amendments to the 2016 NSPS OOOOa made in the 2020 Technical Rule. 
Sources in the transmission and storage segment are subject to the 
methane and VOC standards as promulgated in either the 2012 NSPS OOOO 
or the 2016 NSPS OOOOa, as applicable.\174\ The EPA recognizes that 
certain amendments made to the VOC standards in the 2016 NSPS OOOOa in 
the 2020 Technical Rule, which addressed technical and implementation 
issues in response to administrative petitions for reconsideration and 
other issues brought to the EPA's attention since promulgating the 2016 
NSPS OOOOa rule could also be appropriate to address similar 
implementation issues associated with the methane standards for the 
production and processing segments and the methane and VOC standards 
for the transmission and storage segment. In fact, as mentioned above, 
such revisions were proposed in 2018 but not finalized because these 
standards were removed by the 2020 Policy Rule prior to the EPA's 
promulgation of the 2020 Technical Rule. In light of the above, the EPA 
is proposing to revise 40 CFR part 60, subpart OOOOa, to apply certain 
amendments made in the 2020 Technical Rule to the 2016 NSPS OOOOa for 
methane from the production and processing segments and/or the 2016 
NSPS OOOOa for methane and VOC from the transmission and storage 
segment, as specified in this section.
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    \173\ The only exception is storage vessels, for which the EPA 
did not promulgate methane standards in the 2016 NSPS OOOOa.
    \174\ For the EPA's full explanation of its initial guidance to 
stakeholders on the impact of the CRA, please see https://www.epa.gov/system/files/documents/2021-07/qa_cra_for_2020_oil_and_gas_policy_rule.6.30.2021.pdf.
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    In this action, the EPA is proposing amendments to the 2016 NSPS 
OOOOa to (1) rescind the revisions to the VOC fugitive emissions 
monitoring frequencies at well sites and gathering and boosting 
compressor stations in the 2020 Technical Rule as those revisions were 
not supported by the record for that rule, or by our subsequent 
information and analysis, and (2) adjust other modifications made in 
the 2020 Technical Rule to address technical and implementation issues 
that result from the CRA disapproval of the 2020 Policy Rule. The EPA 
is not reopening any of these prior rulemakings for any other purpose 
in this proposed action. Specifically, the EPA is not reopening any of 
the determinations made in the 2012 NSPS OOOO. In the final rule for 
this action, the EPA will update the NSPS OOOO and NSPS OOOOa 
regulatory text in the CFR to reflect the CRA resolution's disapproval 
of the final 2020 Policy Rule, specifically, the reinstatement of the 
NSPS OOOO and NSPS OOOOa requirements that the 2020 Policy Rule 
repealed but that came back into effect immediately upon enactment of 
the CRA resolution. In accordance with 5 U.S.C. 553(b)(3)(B), the EPA 
is not soliciting comment on these updates. Moreover, the EPA is not 
reopening the methane standards as finalized in the 2016 NSPS OOOOa, 
except as to the specific issues discussed below, nor is the EPA 
reopening any other portions of the 2016 Rule. The EPA is also not 
reopening any determinations made in the 2020 Technical Rule, except as 
to the specific issues discussed below. Finally, the reopening of 
determinations made with respect to the VOC standards in the 2020 
Technical Rule does not indicate any intent to also reopen the methane 
standards for the same affected facilities.

A. Amendments to Fugitive Emissions Monitoring Frequency

    The EPA is proposing to repeal its amendments in the 2020 Technical 
Rule that (1) exempted low production well sites from monitoring 
fugitive emissions and (2) changed from quarterly to semiannual 
monitoring of VOC emissions at gathering and boosting compressor 
stations. The EPA has authority to reconsider a prior action ``as long 
as `the new policy is permissible under the statute. . . , there are 
good reasons for it, and . . . the agency believes it to be better.' '' 
FCC v. Fox Television Stations, Inc., 556 U.S. 502, 515, 129 S. Ct. 
1800, 173 L. Ed. 2d738 (2009).
    The 2016 NSPS OOOOa, as initially promulgated, required semiannual 
monitoring of VOC and methane emissions at all well sites, including 
low production well sites. It also required quarterly monitoring of 
compressor stations, including gathering and boosting compressor 
stations. After issuing the 2020 Policy Rule, which removed all methane 
standards applicable to the production and processing segments and all 
methane and VOC standards applicable to the transmission and storage 
segment, the EPA promulgated the 2020 Technical Rule that further 
amended the VOC standards in the production and processing segment. In 
particular, based on its revised cost analyses, the EPA exempted low 
production well sites from monitoring VOC fugitive emissions and 
changed the frequency of monitoring VOC fugitive emissions from 
quarterly to semiannually at gathering and boosting compressor 
stations. However, as a result of the CRA disapproval of the 2020 
Policy Rule, the low production well sites and the gathering and 
boosting compressor stations continue to be subject to semiannual and 
quarterly monitoring of methane emissions respectively. While it is 
possible for these affected facilities to comply with both the VOC and 
methane monitoring standards that are now in effect, as compliance with 
the more stringent standard would be deemed compliance with the other, 
the EPA reviewed its decisions to amend the VOC monitoring frequencies 
for these affected facilities as well as the underlying record and, for 
the reasons explained below, no longer believe that the amendments are 
appropriate. Therefore, the EPA is proposing to repeal these amendments 
and restore the semiannual and quarterly monitoring requirements for 
low production well sites and gathering and boosting compressor 
stations, as originally promulgated in the 2016 NSPS OOOOa, for both 
methane and VOC.
1. Low Production Well Sites
    As mentioned above, low production well sites are subject to 
semiannual monitoring of fugitive methane emissions. The EPA is 
proposing to repeal the amendment in the 2020 Technical Rule exempting 
low production well sites from monitoring fugitive VOC emissions 
because the analysis for the 2020 Technical Rule supports retaining the 
semiannual monitoring requirement when regulating both VOC and methane 
emissions. While the 2020 Technical Rule amended only the VOC standards 
in the production and processing segments, the EPA evaluated both 
methane and VOC reductions in its final technical support document 
(TSD) (2020 TSD), including the costs associated with different 
monitoring frequencies under the multipollutant approach,\175\ which 
the EPA considers a reasonable approach when regulating multiple 
pollutants. As shown in the 2020 TSD, under the multipollutant 
approach, the cost of semiannual monitoring at low production well 
sites is $850 per ton of methane and $3,058 per ton of VOC reduced, 
both of which are well within the range of what the

[[Page 63159]]

EPA considers to be cost effective.\176\ Nevertheless, the EPA stated 
in the 2020 Technical Rule that ``even if we had not rescinded the 
methane standards in the 2020 Policy Rule, we would still conclude that 
fugitive emissions monitoring, at any of the frequencies evaluated, is 
not cost effective for low production well sites.'' This statement, 
however, is inconsistent with the conclusions on what costs are 
reasonable for the control of methane emissions as discussed in this 
proposal in section IX. More importantly, as an initial matter, this 
statement was based on the EPA's observation in the 2020 Technical Rule 
that the $850 per ton of methane reduced is ``greater than the highest 
value for methane that the EPA determined to be reasonable in the 2016 
NSPS subpart OOOOa,'' which the EPA incorrectly identified as $738/ton; 
the record for the 2016 NSPS OOOOa shows that the EPA considered value 
as high as $2,185/ton to be cost effective for methane reduction. 80 FR 
56627; see also, NSPS OOOOa Final TSD at 93, Table 6-7. Further, even 
with the incorrect observation, the EPA did not conclude in the 2020 
Technical Rule that $850 per ton of methane reduced is therefore 
unreasonable. 85 FR 57420. In fact, the EPA reiterated its prior 
determination that ``a cost of control of $738 per ton of methane 
reduced did not appear excessive,'' and that value was only $112 less 
than the value that the EPA had incorrectly identified as the highest 
methane cost-effectiveness value from the 2016 NSPS OOOOa. As discussed 
above, in fact $738/ton is well within the costs that the EPA concludes 
to be reasonable in the 2016 NSPS OOOOa as well as in this document. 
Also, as explained in section XI.A.2, due to the wide variation in well 
characteristics, types of oil and gas products and production levels, 
gas composition, and types of equipment at well sites, there is 
considerable uncertainty regarding the relationship between the 
fugitive emissions and production levels. Accordingly, the EPA no 
longer believes that production levels provide an appropriate threshold 
for any exemption from fugitive monitoring. See section XI.A.2 for 
additional discussion on the proposed emission thresholds for well site 
fugitive emissions in place of production-based model plants. In light 
of the above, the EPA is proposing to remove the exemption of low 
production well sites from fugitive VOC emissions monitoring, thereby 
restoring the semiannual monitoring requirement established in the 2016 
NSPS OOOOa.
---------------------------------------------------------------------------

    \175\ For purposes of the multipollutant approach, we assume 
that emissions of methane and VOC are controlled at the same time, 
therefore, half of the cost is apportioned to the methane emission 
reductions and half of the cost is apportioned to VOC emission 
reductions.
    \176\ See 2020 NSPS OOOOa Technical Rule TSD at Docket ID No. 
EPA-HQ-OAR-2017-0483-2291. See also section IX, which provides that 
the cost effectiveness values for the controls that we have 
identified as BSER in this action range from $2,200/ton to $5,800/
ton VOC reduction and $700/ton to $2,100/ton of methane reduction. 
As explained in that section, these controls reflect emission 
reduction technologies and methods that many owners and operators in 
the oil and gas industry have employed for years, either voluntarily 
or due to the 2012 and 2016 NSPS, as well as State or other 
requirements.
---------------------------------------------------------------------------

2. Gathering and Boosting Compressor Stations
    The EPA is proposing to repeal its amendment to the VOC monitoring 
frequency for gathering and boosting compressor stations in the 2020 
Technical Rule because the EPA believes that amendment was made in 
error. In that rule, the EPA noted that, based on its revised cost 
analysis, quarterly monitoring has a cost effectiveness of $3,221/ton 
of VOC emissions and an incremental cost of $4,988/ton of additional 
VOC emissions reduced between the semiannual and quarterly monitoring 
frequencies. While the EPA observed that semiannual monitoring is more 
cost effective than quarterly, the EPA nevertheless acknowledged that 
``these values (total and incremental) are considered cost-effective 
for VOC reduction based on past EPA decisions, including the 2016 
rulemaking.'' 85 FR 57421, September 15, 2020. The EPA instead 
identified two additional factors to support its decision to forgo 
quarterly monitoring. First, the EPA stated that the ``Oil and Gas 
Industry is currently experiencing significant financial hardship that 
may weigh against the appropriateness of imposing the additional costs 
associated with more frequent monitoring.'' However, the EPA did not 
offer any data regarding the financial hardship, significant or 
otherwise, the industry was experiencing. While the rule cited to 
several articles on the impact of COVID-19 on the industry, the EPA did 
not discuss any aspect of any of the cited articles that led to its 
conclusion of ``significant financial hardship'' on the industry. Nor 
did the EPA explain how reducing the frequency of a monitoring 
requirement that had been in effect since 2016 would meaningfully 
affect the industry's economic circumstances in any way or weigh those 
considerations against the forgone emission reductions that would 
result from reducing monitoring frequency.
    Second, the EPA generally asserted that ``there are potential 
efficiencies, and potential cost savings, with applying the same 
monitoring frequencies for well sites and compressor stations.'' Again, 
the EPA did not describe what the potential efficiencies are or the 
extent of cost savings that would justify forgoing quarterly 
monitoring, or weigh those efficiencies and cost savings against the 
forgone emission reductions that would result from reducing the 
monitoring frequency for compressor stations. Nor did we explain why 
the Agency's 2016 BSER determination that quarterly monitoring was 
achievable and cost-effective was incorrect in light of these asserted 
efficiencies. On the contrary, based on the compliance records for the 
2016 NSPS OOOOa, there is no indication that compressor stations 
experienced hardship or difficulty in complying with the quarterly 
monitoring requirement. Further, as discussed in section XII.A.1.b, our 
analysis for NSPS OOOOb and EG OOOOc confirms that quarterly monitoring 
remains both achievable and cost-effective for compressor stations, and 
several State agencies also have rules that require quarterly 
monitoring at compressor stations. For the reasons stated above, the 
EPA concludes that it lacked justification and thus erred in revising 
the VOC monitoring frequency for gathering and boosting compressor 
stations from quarterly to semiannual. The EPA is therefore proposing 
to repeal that amendment, thereby restoring the quarterly monitoring 
requirement for gathering and boosting compressor stations, as 
established in the 2016 NSPS OOOOa.

B. Technical and Implementation Amendments

    In the following sections, the EPA describes a series of proposed 
amendments to 2016 NSPS OOOOa for methane to align the 2016 methane 
standards with the current VOC standards (which were modified by the 
2020 Technical Rule). We describe the supporting rationales that were 
provided in the 2020 Technical Rule for modifying the requirements 
applicable to the VOC standards, and explain why the amendments would 
also appropriately apply to the reinstated methane standards.
1. Well Completions
    In the 2020 Technical Rule, the EPA made certain amendments to the 
VOC standards for well completions in the 2016 NSPS OOOOa. For the same 
reasons provided in the 2020 Technical Rule and reiterated below, the 
EPA is proposing to apply the same amendments to the methane standards 
for well completions in the 2016 NSPS OOOOa.
    First, the EPA is proposing to amend the 2016 NSPS OOOOa methane 
standards for well completions to allow

[[Page 63160]]

the use of a separator at a nearby centralized facility or well pad 
that services the well affected facility during flowback, as long as 
the separator can be utilized as soon as it is technically feasible for 
the separator to function. The well completion requirements, as 
promulgated in 2016, had required that the owner or operator of a well 
affected facility have a separator on site during the entire flowback 
period. 81 FR 35901, June 3, 2016. In the 2020 Technical Rule, the EPA 
amended this provision to allow the separator to be at a nearby 
centralized facility or well pad that services the well affected 
facility during flowback as long as the separator can be utilized as 
soon as it is technically feasible for the separator to function. See 
40 CFR 60.5375a(a)(1)(iii). As explained in that rulemaking (85 FR 
57403) and previously in the 2016 NSPS OOOOa final rule preamble, 
``[w]e anticipate a subcategory 1 well to be producing or near other 
producing wells. We therefore anticipate reduced emission completion 
(REC) equipment (including separators) to be onsite or nearby, or that 
any separator brought onsite or nearby can be put to use.'' 81 FR 
35852, June 3, 2016. For the same reason, the EPA is proposing to make 
the same amendment to the methane standards for well completions.
    Additionally, the 2020 Technical Rule amended 40 CFR 
60.5375a(a)(1)(i) to clarify that the separator that is required during 
the initial flowback stage may be a production separator as long as it 
is also designed to accommodate flowback. As explained in the preamble 
to the final 2020 Technical Rule, when a production separator is used 
for both well completions and production, the production separator is 
connected at the onset of the flowback and stays on after flowback and 
at the startup of production. 85 FR 57403, September 15, 2020. For the 
same reason, the EPA is proposing the same clarification apply to the 
methane standards for well completions.
    The 2020 Technical Rule also amended the definition of flowback. In 
2016, the EPA defined ``flowback'' as the process of allowing fluids 
and entrained solids to flow from a well following a treatment, either 
in preparation for a subsequent phase of treatment or in preparation 
for cleanup and returning the well to production. Flowback also means 
the fluids and entrained solids that emerge from a well during the 
flowback process. The flowback period begins when material introduced 
into the well during the treatment returns to the surface following 
hydraulic fracturing or refracturing. The flowback period ends when 
either the well is shut in and permanently disconnected from the 
flowback equipment or at the startup of production. The flowback period 
includes the initial flowback stage and the separation flowback stage. 
81 FR 35934, June 3, 2016.
    The 2020 Technical Rule amended this definition by adding a 
clarifying statement that ``[s]creenouts, coil tubing cleanouts, and 
plug drill-outs are not considered part of the flowback process.'' 40 
CFR 60.5430a. In the proposal for the 2020 Technical Rule, the EPA 
explained that screenouts, coil tubing cleanouts, and plug drill outs 
are functional processes that allow for flowback to begin; as such, 
they are not part of the flowback. 83 FR 52082, October 15, 2018. In 
conjunction with this amendment, the 2020 Technical Rule added 
definitions for screenouts, coil tubing cleanouts, and plug drill outs. 
See 40 CFR 60.5430a. Specifically, a screenout is an attempt to clear 
proppant from the wellbore in order to dislodge the proppant out of the 
well. A coil tubing cleanout is a process where an operator runs a 
string of coil tubing to the packed proppant within a well and jets the 
well to dislodge the proppant and provide sufficient lift energy to 
flow it to the surface. A plug drill-out is the removal of a plug (or 
plugs) that was used to isolate different sections of the well. For the 
reason stated above, the EPA is proposing to apply the definitions of 
flowback, screenouts, coil tubing cleanouts, and plug drill outs that 
were finalized in the 2020 Technical Rule to the methane standards for 
well completions in the 2016 NSPS OOOOa.
    Finally, the 2020 Technical Rule amended specific recordkeeping and 
reporting requirements for the VOC standards for well completions, and 
the EPA is proposing to apply these amendments to the methane standards 
for well completions in the 2016 NSPS OOOOa. For the reasons explained 
in 83 FR 52082, the 2020 Technical Rule requires that for each well 
site affected facility that routes flowback entirely through one or 
more production separators, owners and operators must record and report 
only the following data elements:
     Well Completion ID;
     Latitude and longitude of the well in decimal degrees to 
an accuracy and precision of five (5) decimals of a degree using North 
American Datum of 1983;
     U.S. Well ID;
     The date and time of the onset of flowback following 
hydraulic fracturing or refracturing or identification that the well 
immediately starts production; and
     The date and time of the startup of production.
    While the 2020 Technical Rule removed certain reporting 
requirements (e.g., information about when a separator is hooked up or 
disconnected during flowback) as unnecessary or redundant, 85 FR 57403, 
the rule added a requirement that for periods where salable gas is 
unable to be separated, owners and operators must record and report the 
date and time of onset of flowback, the duration and disposition of 
recovery, the duration of combustion and venting (if applicable), 
reasons for venting (if applicable), and deviations.
    As explained in the preamble to the proposal for the 2020 Technical 
Rule, when a production separator is used for both well completions and 
production, the production separator is connected at the onset of the 
flowback and stays on after flowback and at the startup of production; 
in that event, certain reporting and recordkeeping requirements 
associated with well completions (e.g., information about when a 
separator is hooked up or disconnected during flowback) would be 
unnecessary. 83 FR 52082. Because these amendments to the recordkeeping 
and reporting requirements associated with well completion are 
independent of the specific pollutant being regulated, we are proposing 
these same amendments to the methane standards for well completions in 
the 2016 NSPS OOOOa.
2. Pneumatic Pumps
    In the 2020 Technical Rule, the EPA made certain amendments to the 
VOC standards for pneumatic pumps in the 2016 NSPS OOOOa. For the same 
reasons provided in the 2020 Technical Rule, along with further 
explanation provided below, the EPA is proposing to apply the same 
amendments to the methane standards for pneumatic pumps in the 2016 
NSPS OOOOa.
    First, the EPA is proposing to amend the 2016 NSPS OOOOa methane 
standards for pneumatic pumps to expand the technical infeasibility 
provision to apply to pneumatic pumps at greenfield sites. Under the 
2016 NSPS OOOOa, ``emissions from new, modified, and reconstructed 
natural gas-driven diaphragm pumps located at well sites [must] be 
reduced by 95 percent if either a control device or the ability to 
route to a process is already available onsite, unless it is 
technically infeasible at sites other than new developments (i.e., 
greenfield sites).'' 81 FR 35824 and 35844. For the 2016 NSPS OOOOa, 
the EPA concluded that circumstances that could otherwise make control 
of a pneumatic pump technically infeasible

[[Page 63161]]

at an existing location could be addressed in the design and 
construction of a greenfield site. 81 FR 35849 and 35850 (June 3, 
2016). Concerns raised in petitions for reconsideration on the 2016 
NSPS OOOOa explained that, even at greenfield sites, certain scenarios 
present circumstances where the control of a pneumatic pump may be 
technically infeasible despite the site being newly designed and 
constructed.\177\ These circumstances include, but are not limited to, 
site designs requiring high-pressure flares to which routing a low-
pressure pump discharge is not feasible and use of small boilers or 
process heaters that are insufficient to control pneumatic pump 
emissions or that could result in safety trips and burner flame 
instability. The EPA proposed to extend the technical infeasibility 
exemption to greenfield sites in 2018 and sought comment on these 
circumstances that could preclude control of a pneumatic pump at 
greenfield sites. While the EPA received comments both in favor of and 
opposing the application of the technical infeasibility exemption to 
greenfield sites, the commenters did not identify a reasoned basis for 
the EPA to decline to extend the exemption. See Response to Comments 
(RTC) for 2020 Technical Rule at 5-1 to 5-4 at Docket ID No. EPA-HQ-
OAR-2017-0483. Moreover, the EPA specifically sought information 
regarding the additional costs that would be incurred if owners and 
operators of greenfield sites were required to select a control that 
can accommodate pneumatic pump emissions in addition to the control's 
primary purpose at a new construction site, but no such information was 
provided.
---------------------------------------------------------------------------

    \177\ See proposal for 2020 Technical Rule at 83 FR 52061.
---------------------------------------------------------------------------

    The 2020 Technical Rule therefore expanded the technical 
infeasibility provision to apply to pneumatic pumps at all well sites, 
including new developments (greenfield sites), concluding that the 
extension was appropriate because the EPA identified circumstances 
where it may not be technically feasible to control pneumatic pumps at 
a greenfield site. The 2020 Technical Rule removed the reference to 
greenfield site in 40 CFR 60.5393a(b) and the associated definition of 
greenfield site at 40 CFR 60.5430a.
    In the final rule preamble for the 2016 NSPS OOOOa, the EPA stated 
we did not intend to require the installation of a control device at a 
well site for the sole purpose of controlling emissions from a 
pneumatic pump, but rather only required control of pneumatic pumps to 
the extent a control device or process would already be available on 
site. It is not the EPA's intent to require a greenfield site to 
install a control device specifically for controlling emissions from a 
pneumatic pump. It is our understanding that sites are designed to 
maximize operation and safety. This includes the placement of 
equipment, such as control devices. Because vented gas from pneumatic 
pumps is at low pressure, it may not be feasible to move collected gas 
through a closed vent system to a control device, depending on site 
design. Therefore, the EPA continues to conclude that, when determining 
technical feasibility at any site, such a determination should consider 
the routing of pneumatic pump emissions to the controls which are 
needed for the other processes at the site (i.e., not the pneumatic 
pump). The owner or operator must justify and provide professional or 
in-house engineering certification for any site where the control of 
pneumatic pump emissions is technically infeasible. As explained in the 
RTC for the 2020 Technical Rule, ``[t]he EPA believes that the 
requirement to certify an engineering assessment to demonstrate 
technical infeasibility provides protection against an owner or 
operator purposely designing a new site just to avoid routing emissions 
from a pneumatic pump to an onsite control device or to a process.'' 
\178\ For the reasons explained above, the EPA is proposing to align 
the methane standards in the 2016 NSPS OOOOa for controlling pneumatic 
pump emissions with the amendments made to the VOC standards in the 
2020 Technical Rule to allow for a well-justified determination of 
technical infeasibility at all well sites, including greenfield sites.
---------------------------------------------------------------------------

    \178\ See Docket ID No. EPA-HQ-OAR-2017-0483-2291. ``For 
example, consider the example provided by one commenter where a new 
site design requires only a high-pressure flare to control emergency 
and maintenance blowdowns and it is not feasible for a low-pressure 
pneumatic pump discharge to be routed to such a flare. The 
infeasibility determination would need not only demonstrate that it 
is not feasible for a low-pressure pneumatic pump discharge to be 
directly routed to the flare, it would also need to demonstrate that 
it is infeasible to design and install a low-pressure header to 
allow routing this discharge to such a flare system.'' RTC at 5-4.
---------------------------------------------------------------------------

    Second, the 2020 Technical Rule amended the 2016 NSPS OOOOa to 
specify that boilers and process heaters are not considered control 
devices for the purposes of the pneumatic pump standards. It is the 
EPA's understanding, based on information provided in reconsideration 
petitions \179\ submitted regarding the 2016 NSPS OOOOa and comments 
received on the proposal for the 2020 Technical Rule, that some boilers 
and process heaters located at well sites are not inherently designed 
for the control of emissions. While it is true that for some other 
sources (not pneumatic pumps), boilers and process heaters may be 
designed as control devices, that is generally not the operational 
purpose of this equipment at a well site. Instead, it is the EPA's 
understanding that boilers and process heaters operate seasonally, 
episodically, or otherwise intermittently as process devices, thus 
making the use of these devices as controls inefficient and non-
compliant with the continuous control requirements at 40 CFR 
60.5415a.\180\ Further, as explained in the 2020 Technical Rule, the 
fact that some boilers and process heaters located at well sites are 
not inherently designed to control emissions means that ``routing 
pneumatic pump emissions to these devices may result in frequent safety 
trips and burner flame instability (e.g., high temperature limit 
shutdowns and loss of flame signal).'' Id. The EPA determined that 
``requiring the technical infeasibility evaluation for every boiler and 
process heater located at a wellsite would result in unnecessary 
administrative burden since each such evaluation would be raising 
the[se] same concerns.'' 85 FR 57404 (September 15, 2020). Further, as 
described above, the EPA did not intend to require the installation of 
a control device for the sole purpose of controlling emissions from 
pneumatic pumps. Based on the EPA's understanding that boilers and 
process heaters located at well sites are designed and operated as 
process equipment (meaning they are not inherently designed for the 
control of emissions), the EPA also does not intend to require their 
continuous operation solely to control emissions from pneumatic pumps 
either. Therefore, the EPA is proposing to align the methane standards 
for pneumatic pumps with the 2020 Technical Rule to specify that 
boilers and process heaters are not considered control devices for the 
purposes of controlling pneumatic pump emissions. The EPA solicits 
comment on this alignment, including whether there are specific 
examples where boilers and process heaters are

[[Page 63162]]

currently used as control devices at well sites.
---------------------------------------------------------------------------

    \179\ See Docket ID No. EPA-HQ-OAR-2017-0483-0016.
    \180\ See Docket ID No. EPA-HQ-OAR-2017-0483-0016.
---------------------------------------------------------------------------

    Third, the EPA is proposing to align the certification requirements 
for the determination that it is technically infeasible to route 
emissions from a pneumatic pump to a control device or process. The 
2016 NSPS OOOOa required certification of technical infeasibility by a 
qualified third-party Professional Engineer (PE); however, the 2020 
Technical Rule allows this certification by either a PE or an in-house 
engineer, because in-house engineers may be more knowledgeable about 
site design and control than a third-party PE. The EPA continues to 
believe that certification by an in-house engineer is appropriate for 
this purpose. We are, therefore, proposing to align the methane 
standards in the 2016 NSPS OOOOa with the 2020 Technical Rule to allow 
certification of technical infeasibility by either a PE or an in-house 
engineer with expertise on the design and operation of the pneumatic 
pump. We are soliciting comment on this proposed alignment.
3. Closed Vent Systems (CVS)
    As in the 2020 Technical Rule, the EPA is proposing to allow 
multiple options for demonstrating that there are no detectable methane 
emissions from CVS. Additionally, the EPA is proposing to allow either 
a PE or an in-house engineer with expertise on the design and operation 
of the CVS to certify the design and operation will meet the 
requirement to route all vapors to the control device or back to the 
process.
    The methane standards in the 2016 NSPS OOOOa require that CVS be 
operated with no detectable emissions, as demonstrated through specific 
monitoring requirements associated with the specific affected 
facilities (i.e., pneumatic pumps, centrifugal compressors, 
reciprocating compressors, and storage vessels). Relevant here, the 
2016 NSPS OOOOa required this demonstration for both VOC and methane 
emissions through annual inspections using EPA Method 21 for CVS 
associated with pneumatic pumps, while requiring storage vessels to 
conduct monthly audio, visual, olfactory (AVO) monitoring. The 2020 
Technical Rule amended the VOC requirements for CVS for pneumatic pumps 
to align the requirements for pneumatic pumps and storage vessels by 
incorporating provisions allowing the option to demonstrate the 
pneumatic pump CVS is operated with no detectable emissions by either 
an annual inspection using EPA Method 21, monthly AVO monitoring, or 
OGI monitoring at the frequencies specified for fugitive emissions 
monitoring. The EPA is proposing to amend the methane standards to 
allow pneumatic pump affected facilities to permit these same options 
to demonstrate no detectable methane emissions from CVS either using 
annual Method 21 monitoring, as currently required by the 2016 NSPS 
OOOOa, or using either monthly AVO monitoring or OGI monitoring at the 
fugitive monitoring frequency. The EPA considers these detection 
options appropriate for CVS associated with pneumatic pumps because any 
of the three would detect methane as well as VOC emissions. We 
incorporated the option for monthly AVO monitoring in the 2020 
Technical Rule because pneumatic pumps and controlled storage vessels 
are commonly located at the same site and having separate monitoring 
requirements for a potentially shared CVS is overly burdensome and 
duplicative. 83 FR 52083 (October 15, 2018). We further incorporated 
the option for OGI monitoring because OGI is already being used for 
those sites that are subject to fugitive emissions monitoring and the 
CVS can readily be monitored during the fugitive emissions survey at no 
extra cost. 85 FR 57405. The EPA believes it is appropriate to maintain 
these options because not all well sites with controlled pneumatic 
pumps will be subject to fugitive emissions monitoring (e.g., pneumatic 
pumps located at existing well sites that have not triggered the 
fugitive monitoring requirements for new or modified well sites) and 
requiring either OGI or EPA Method 21 survey of the CVS for the 
pneumatic pump in the absence of fugitive emissions surveys would be 
unreasonable. It is possible for a new pneumatic pump to be subject to 
control at an existing well site that is not subject to the fugitive 
emissions requirements. Requiring either EPA Method 21 or OGI for the 
sole purpose of monitoring the CVS associated with the pneumatic pump 
would be too costly,\181\ therefore we continue to believe monthly AVO 
is an appropriate option for pneumatic pumps subject to the 2016 NSPS 
OOOOa.
---------------------------------------------------------------------------

    \181\ Both OGI and EPA Method 21 have significant capital and 
annual costs, including the cost of specialized equipment and 
trained operators of that equipment. While the costs of these 
programs are justified for well site fugitive emission monitoring 
based on the assumption of a high component count from which 
emissions would be controlled, the CVS is only one of those many 
components. Thus, where well site fugitive monitoring is not 
otherwise required, the cost-effectiveness of OGI or EPA Method 21 
would be significantly higher for the CVS alone.
---------------------------------------------------------------------------

    Additionally, the 2020 Technical Rule amended the 2016 NSPS OOOOa 
to allow certification of the design and operation of CVS by an in-
house engineer with expertise on the design and operation of the CVS in 
lieu of a PE. This certification is necessary to ensure the design and 
operation of the CVS will meet the requirement to route all vapors to 
the control device or back to the process. As explained in the proposal 
for the 2020 Technical Rule, 83 FR 52079, the EPA allows CVS 
certification by either a PE or an in-house engineer because in-house 
engineers may be more knowledgeable about site design and control than 
a third-party PE. For the same reason, the EPA is proposing to amend 
the CVS requirements associated with methane emissions in the 
production and processing segments, and methane and VOC emissions in 
the transmission and storage segment, to allow certification of the 
design and operation of CVS by either a PE or an in-house engineer with 
expertise on the design and operation of the CVS.
4. Fugitive Emissions at Well Sites and Compressor Stations
a. Well Sites
    The EPA is proposing to exclude from fugitive emissions monitoring 
a well site that is or later becomes a ``wellhead only well site,'' 
which the 2020 Technical Rule defines as ``a well site that contains 
one or more wellheads and no major production and processing 
equipment.'' The 2016 NSPS OOOOa excludes well sites that contain only 
one or more wellheads from the fugitive emissions requirements because 
fugitive emissions at such well sites are extremely low. 80 FR 56611. 
As explained in that rulemaking, ``[s]ome well sites, especially in 
areas with very dry gas or where centralized gathering facilities are 
used, consist only of one or more wellheads, or `Christmas trees,' and 
have no ancillary equipment such as storage vessels, closed vent 
systems, control devices, compressors, separators and pneumatic 
controllers. Because the magnitude of fugitive emissions depends on how 
many of each type of component (e.g., valves, connectors, and pumps) 
are present, fugitive emissions from these well sites are extremely 
low.'' 80 FR 56611. The 2020 Technical Rule amended the 2016 NSPS OOOOa 
to exclude from fugitive emissions monitoring a well site that is or 
later becomes a ``wellhead only well site,'' which the 2020 Technical 
Rule defines as ``a well site that contains one or more wellheads and 
no major production and processing equipment.'' The 2020 Technical Rule 
defined ``major production and processing equipment''

[[Page 63163]]

as including reciprocating or centrifugal compressors, glycol 
dehydrators, heater/treaters, separators, and storage vessels 
collecting crude oil, condensate, intermediate hydrocarbon liquids, or 
produced water. We continue to believe that available information, 
including various studies,\182\ supports an exemption for well sites 
that do not have this major production and processing equipment. The 
2020 Technical Rule allows certain small ancillary equipment, such as 
chemical injection pumps, pneumatic controllers used to control well 
emergency shutdown valves, and pumpjacks, that are associated with, or 
attached to, the wellhead and ``Christmas tree'' to remain at a 
``wellhead only well site'' without being subject to the fugitive 
emissions monitoring requirements because they have very few fugitive 
emissions components that would leak, and therefore have limited 
potential for fugitive emissions. The emission reduction benefits of 
continuing monitoring at that point would be relatively low, and thus 
would not be cost-effective.
---------------------------------------------------------------------------

    \182\ See https://pubs.acs.org/doi/10.1021/acs.est.0c02927, 
https://data.permianmap.org/pages/flaring, and https://www.edf.org/sites/default/files/documents/PermianMapMethodology_1.pdf.
---------------------------------------------------------------------------

    For the reason stated above, the EPA is proposing to amend the 2016 
NSPS OOOOa to allow monitoring of methane fugitive emissions to stop 
when a wellsite contains only wellhead(s) and no major production and 
processing equipment, as provided in the 2020 Technical Rule.
b. Compressor Stations
    As discussed above, the 2016 NSPS OOOOa required quarterly 
monitoring of compressor stations for both VOC and methane emissions, 
and it also permitted waiver from one quarterly monitoring event when 
the average temperature is below 0 [deg]F for two consecutive months 
because it is technically infeasible for the OGI camera (and EPA Method 
21 instruments) to operate below this temperature. After the 2020 
Policy Rule rescinded the methane standards, the 2020 Technical Rule 
reduced the monitoring requirements for the VOC standards to require 
only semiannual monitoring and, in doing so, removed the waiver. Upon 
enactment of the CRA resolution, compressor stations again became 
subject to quarterly monitoring pursuant to the reinstated 2016 NSPS 
OOOOa methane standards, and the waiver as it applied to the methane 
standards was also reinstated. Consistent with our proposal to align 
the monitoring requirements for VOCs with the monitoring requirements 
for methane, the EPA is also proposing to reinstate the waiver for the 
VOC standards as specified in the 2016 NSPS OOOOa.
c. Well Sites and Compressor Stations on the Alaska North Slope
    The EPA is proposing to amend the 2016 NSPS OOOOa to require that 
new, reconstructed, and modified compressor stations located on the 
Alaska North Slope that startup (initially, or after reconstruction or 
modification) between September and March to conduct initial monitoring 
of methane emissions within 6 months of startup, or by June 30, 
whichever is later. The EPA made a similar amendment to the initial 
monitoring of methane and VOC emissions at well sites located on the 
Alaska North Slope in the March 12, 2018 amendments to the 2016 NSPS 
OOOOa (``2018 NSPS OOOOa Rule'').\183\ As explained in that action, 
such separate requirements were warranted due to the area's extreme 
cold temperatures, which for approximately half of the year are below 
the temperatures at which the monitoring instruments are designed to 
operate. The 2020 Technical Rule made this amendment for VOC emissions 
from gathering and boosting compressor stations located in the Alaska 
North Slope for this same reason.
---------------------------------------------------------------------------

    \183\ 83 FR 10628 (March 12, 2018).
---------------------------------------------------------------------------

    The EPA is also proposing to amend the 2016 NSPS OOOOa to require 
annual monitoring of methane and VOC emissions at all compressor 
stations located on the Alaska North Slope, with subsequent annual 
monitoring at least 9 months apart but no more than 13 months apart. In 
the 2018 NSPS OOOOa Rule, the EPA similarly amended the monitoring 
frequency for well sites located on the Alaska North Slope to annual 
monitoring to accommodate the extreme cold temperature. 83 FR 10628 
(March 12, 2018). For the same reason, in the 2020 Technical Rule, the 
EPA amended the 2016 NSPS OOOOa to require annual VOC monitoring at 
gathering and boosting compressor stations located on the Alaska North 
Slope because extreme cold temperatures make it technically infeasible 
to conduct OGI monitoring for over half of a year.\184\ Because the 
same difficulties would arise with respect to monitoring for fugitive 
methane emissions from gathering and boosting compressor stations or to 
monitoring of methane and VOC emissions from compressor stations in the 
transmission and storage segment, the EPA is proposing to amend the 
2016 NSPS OOOOa to require that all compressor stations located on the 
Alaska North Slope conduct annual monitoring of both methane and VOC 
emissions.
---------------------------------------------------------------------------

    \184\ See Docket ID Nos. EPA-HQ-OAR-2010-0505-7682 and EPA-HQ-
OAR-2010-0505-12434. See also FLIR Systems, Inc. product 
specifications for GF300/320 model OGI cameras at http://www.flir.com/ogi/display/?id=55671 and Thermo Fisher Scientific 
product specification for TVA-2020 at https://assets.thermofisher.com/TFS-Assets/LSG/Specification-Sheets/EPM-TVA2020.pdf.
---------------------------------------------------------------------------

    Further, the EPA is proposing to extend the deadline for conducting 
initial monitoring of both VOC and methane emissions from 60 days to 90 
days for all well sites and compressor stations located on the Alaska 
North Slope that startup or are modified between April and August. In 
the 2020 Technical Rule, the EPA made this amendment for initial VOC 
monitoring to allow the well site or gathering and boosting compressor 
station to reach normal operating conditions. 85 FR 57406. For the same 
reason, we are proposing to further amend the 2016 NSPS OOOOa to apply 
this same 90-day initial monitoring requirement to initial monitoring 
of fugitive methane and VOC emissions from all well sites and 
compressor stations located on the Alaska North Slope that startup or 
are modified between April and August.
d. Modification
    The 2016 NSPS OOOOa, as originally promulgated, provided that 
``[f]or purposes of the fugitive emissions standards at 40 CFR 
60.5397a, [a] well site also means a separate tank battery surface site 
collecting crude oil, condensate, intermediate hydrocarbon liquids, or 
produced water from wells not located at the well site (e.g., 
centralized tank batteries).'' 40 CFR 60.5430a. However, the original 
2016 NSPS OOOOa defined ``modification'' only with respect to a well 
site and was silent on what constitutes modification to a well site 
that is a separate tank battery surface site. Specifically, 40 CFR 
60.5365a(i), as promulgated in 2016, specified that, for the purposes 
of fugitive emissions components at a well site, a modification occurs 
when (1) a new well is drilled at an existing well site, (2) a well is 
hydraulically fractured at an existing well site, or (3) a well is 
hydraulically refractured at an existing well site. See 40 CFR 
60.5365a(i).
    Because this provision was silent on when modification occurs at a 
well site that is a separate tank battery surface site, the 2020 
Technical Rule added language to clarify that a modification of a well 
site that is a separate tank battery surface site occurs when (1) any 
of the actions listed above for well sites occurs

[[Page 63164]]

at an existing separate tank battery surface site, (2) a well modified 
as described above sends production to an existing separate tank 
battery surface site, or (3) a well site subject to the fugitive 
emissions requirements removes all major production and processing 
equipment such that it becomes a wellhead-only well site and sends 
production to an existing separate tank battery surface site. Because 
the 2020 Technical Rule amended only the VOC standards in the 2016 NSPS 
OOOOa, and since this definition of modification equally applies to 
fugitive methane emissions from a separate tank battery surface site, 
the EPA is proposing to apply this definition of modification for 
purposes of determining when modification occurs at a separate tank 
battery surface site triggering the methane standards for fugitive 
emissions at well sites.
e. Initial Monitoring for Well Sites and Compressor Stations
    The 2016 NSPS OOOOa, as originally promulgated, had required 
monitoring of methane and VOC fugitive emissions at well sites and 
compressor stations to begin within 60 days of startup (of production 
in the case of well sites) or modification. The 2020 Technical Rule 
extended this time frame to 90 days for well sites and gathering and 
boosting compressor stations in response to comments stating that well 
sites and compressor stations do not achieve normal operating 
conditions within the first 60 days of startup and suggesting that the 
EPA allow 90 days to 180 days. The EPA agreed that additional time to 
allow the well site or compressor station to reach normal operating 
conditions is warranted, considering the purpose of the initial 
monitoring is to identify any issues associated with installation and 
startup of the well site or compressor station. By providing sufficient 
time to allow owners and operators to conduct the initial monitoring 
survey during normal operating conditions, the EPA expects that there 
will be more opportunity to identify and repair sources of fugitive 
emissions, whereas a partially operating site may result in missed 
emissions that remain unrepaired for a longer period of time. 85 FR 
57406. These same reasons apply regardless of pollutant or the location 
of the compressor station; therefore, the EPA is proposing to further 
amend the 2016 NSPS OOOOa to extend the deadline for conducting initial 
monitoring from 60 to 90 days for monitoring both VOC and methane 
fugitive emissions at all well sites and compressor stations (except 
those on the Alaska North Slope which are separately regulated as 
discussed in section X.B.4.c).
f. Repair Requirements
    The 2020 Technical Rule made certain amendments to the 2016 NSPS 
OOOOa repair requirements associated with monitoring of fugitive VOC 
emissions at well sites and gathering and boosting compressor stations. 
For the same reasons provided in the 2020 Technical Rule and reiterated 
below, the EPA is proposing to similarly amend the 2016 NSPS OOOOa 
repair requirements associated with monitoring of methane emissions at 
well sites and gathering and boosting compressor stations and 
monitoring of VOC and methane fugitive emissions at compressor stations 
in the transmission and storage segment.
    Specifically, the EPA is proposing to require a first attempt at 
repair within 30 days of identifying fugitive emissions and final 
repair, including the resurvey to verify repair, within 30 days of the 
first attempt at repair. The 2016 NSPS OOOOa, as originally 
promulgated, required repair within 30 days of identifying fugitive 
emissions and a resurvey to verify that the repair was successful 
within 30 days of the repair. Stakeholders raised questions regarding 
whether emissions identified during the resurvey would result in 
noncompliance with the repair requirement. In the 2020 Technical Rule, 
the EPA clarified that repairs should be verified as successful prior 
to the repair deadline and added definitions for the terms ``first 
attempt at repair'' and ``repaired.'' Specifically, the definition of 
``repaired'' includes the verification of successful repair through a 
resurvey of the fugitive emissions component. The EPA is similarly 
proposing to apply these amendments to the repair requirements made in 
the 2020 Technical Rule to the repair requirements associated with 
monitoring of methane emissions at well sites and gathering and 
boosting compressor stations as well as monitoring of VOC and methane 
fugitive emissions at compressor stations in the transmission and 
storage segment and monitoring.
    In addition, the EPA is proposing that delayed repairs be completed 
during the ``next scheduled compressor station shutdown for 
maintenance, scheduled well shutdown, scheduled well shut-in, after a 
scheduled vent blowdown, or within 2 years, whichever is earliest.'' 
The proposed amendment would clarify that completion of delayed repairs 
is required during scheduled shutdown for maintenance, and not just any 
shutdown.
    In 2018 NSPS OOOOa Rule the EPA amended the 2016 NSPS OOOOa to 
specify that, where the repair of a fugitive emissions component is 
``technically infeasible, would require a vent blowdown, a compressor 
station shutdown, a well shutdown or well shut-in, or would be unsafe 
to repair during operation of the unit, the repair must be completed 
during the next scheduled compressor station shutdown, well shutdown, 
well shut-in, after a planned vent blowdown, or within 2 years, 
whichever is earlier.'' \185\ During the rulemaking for the 2020 
Technical Rule, the EPA received comments expressing concerns with 
requiring repairs during the next scheduled compressor station 
shutdown, without regard to whether the shutdown is for maintenance 
purposes. The commenters stated that repairs must be scheduled and that 
where a planned shutdown is for reasons other than scheduled 
maintenance, completion of the repairs during that shutdown may be 
difficult and disrupt gas transmission. The EPA agrees that requiring 
the completion of delayed repairs only during those scheduled 
compressor station shutdowns where maintenance activities are scheduled 
is reasonable and anticipates that these maintenance shutdowns occur on 
a regular schedule. Accordingly, in the 2020 Technical Rule the EPA 
further amended this provision by adding the term ``for maintenance'' 
to clarify that repair must be completed during the ``next scheduled 
compressor station shutdown for maintenance'' or other specified 
scheduled events, or within 2 years, whichever is the earliest. For the 
same reason, the EPA is proposing the same clarifying amendment to the 
delay of repair requirements for fugitive methane emissions at well 
sites and gathering and boosting compressor stations and fugitive VOC 
and methane fugitive emissions at compressor stations in the 
transmission and storage segment.
---------------------------------------------------------------------------

    \185\ 83 FR 10638, 40 CFR 60.5397a(h)(2).
---------------------------------------------------------------------------

g. Definitions Related to Fugitive Emissions at Well Sites and 
Compressor Stations
    The 2020 Technical Rule made certain amendments to the definition 
of a well site and the definition for startup of production as they 
relate to fugitive VOC emissions requirements at well sites. For the 
same reasons provided in the 2020 Technical Rule and reiterated below, 
the EPA is proposing to similarly amend these definitions as they 
relate to the fugitive methane emissions requirements at well sites.

[[Page 63165]]

    The 2020 Technical Rule amended the definition of well site, for 
purposes of VOC fugitive emissions monitoring, to exclude equipment 
owned by third parties and oilfield solid waste and wastewater disposal 
wells. The amended definition for ``well site'' excludes third party 
equipment from the fugitive emissions requirements by excluding ``the 
flange immediately upstream of the custody meter assembly and 
equipment, including fugitive emissions components located downstream 
of this flange.'' To clarify this exclusion, the 2020 Technical Rule 
defines ``custody meter'' as ``the meter where natural gas or 
hydrocarbon liquids are measured for sales, transfers, and/or royalty 
determination,'' and the ``custody meter assembly'' as ``an assembly of 
fugitive emissions components, including the custody meter, valves, 
flanges, and connectors necessary for the proper operation of the 
custody meter.'' This exclusion was added for several reasons, 
including consideration that owners and operators may not have access 
or authority to repair this third-party equipment and because the 
custody meter ``is used effectively as the cash register for the well 
site and provides a clear separation for the equipment associated with 
production of the well site, and the equipment associated with putting 
the gas into the gas gathering system.'' 83 FR 52077 (October 15, 
2018).
    The definition of a well site was also amended in the 2020 
Technical Rule to exclude Underground Injection Control (UIC) Class I 
oilfield disposal wells and UIC Class II oilfield wastewater disposal 
wells. The EPA had proposed to exclude UIC Class II oilfield wastewater 
disposal wells because of our understanding that they have negligible 
fugitive VOC and methane emissions. 83 FR 52077. Comments received on 
the 2020 Technical rulemaking effort further suggested, and the EPA 
agreed, that we also should exclude UIC Class I oilfield disposal wells 
because of their low VOC and methane emissions. Both types of disposal 
wells are permitted through UIC programs under the Safe Drinking Water 
Act for protection of underground sources of drinking water. For 
consistency, the 2020 Technical Rule adopted the definitions for UIC 
Class I oil field disposal wells and UIC Class II oilfield wastewater 
disposal wells under the Safe Drinking Water Act definitions in 
excluding them from the definition of a well site in the 2016 NSPS 
OOOOa. Specifically, the 2020 Technical Rule defined a UIC Class I 
oilfield disposal well as ``a well with a UIC Class I permit that meets 
the definition in 40 CFR 144.6(a)(2) and receives eligible fluids from 
oil and natural gas exploration and production operations.'' 
Additionally, the 2020 Technical Rule defines a UIC Class II oilfield 
wastewater disposal well as ``a well with a UIC Class II permit where 
wastewater resulting from oil and natural gas production operations is 
injected into underground porous rock formations not productive of oil 
or gas, and sealed above and below by unbroken, impermeable strata.'' 
As amended, UIC Class I and UIC Class II disposal wells are not 
considered well sites for the purposes of VOC fugitive emissions 
requirements. Because the 2020 Technical Rule, as finalized, addressed 
only VOC emissions in the production and processing segment, the EPA is 
proposing the same exclusion and definition of ``well site'' for the 
purposes of fugitive emissions monitoring of methane emissions at well 
sites.
    The EPA is also proposing to apply the definition for ``startup of 
production'' for purposes of well site fugitive emissions requirements 
for VOC to these requirements as they relate to methane. The 2016 NSPS 
OOOOa initially contained a definition for ``startup of production'' as 
it relates to the well completion standards that reduce emissions from 
hydraulically fractured wells. For that purpose, the term was defined 
as ``the beginning of initial flow following the end of flowback when 
there is continuous recovery of salable quality gas and separation and 
recovery of any crude oil, condensate or produced water.'' 81 FR 25936 
(June 3, 2016). The 2020 Technical Rule amended the definition of 
``startup of production'' to separately define the term as it relates 
to fugitive VOC emissions requirements at well sites. Specifically, ``. 
. .[f]or the purposes of the fugitive monitoring requirements of 40 CFR 
60.5397a, startup of production means the beginning of the continuous 
recovery of salable quality gas and separation and recovery of any 
crude oil, condensate or produced water'' 85 FR 57459 (September 15, 
2020). This separate definition clarifies that fugitive emissions 
monitoring applies to both conventional and unconventional 
(hydraulically fractured) wells. For this same reason, the EPA is 
proposing to apply this same definition of ``startup of production'' to 
fugitive emissions monitoring of methane emissions at well sites.
h. Monitoring Plan
    The 2016 NSPS OOOOa, as originally promulgated, required that each 
fugitive emissions monitoring plan include a site map and a defined 
observation path to ensure that the OGI operator visualizes all of the 
components that must be monitored during each survey. The 2020 
Technical Rule amended this requirement to allow the company to specify 
procedures that would meet this same goal of ensuring every component 
is monitored during each survey. While the site map and observation 
path are one way to achieve this, other options can also ensure 
monitoring, such as an inventory or narrative of the location of each 
fugitive emissions component. The EPA stated in the 2020 Technical Rule 
that ``these company-defined procedures are consistent with other 
requirements for procedures in the monitoring plan, such as the 
requirement for procedures for determining the maximum viewing distance 
and maintaining this viewing distance during a survey.'' 85 FR 57416 
(September 15, 2020). Because the same monitoring device is used to 
monitor both methane and VOC emissions, the same company-defined 
procedures for ensuring each component is monitored are appropriate. 
Therefore, the EPA is proposing to similarly amend the monitoring plan 
requirements for methane and for compressor stations to allow company 
procedures in lieu of a sitemap and an observation path.
i. Recordkeeping and Reporting
    The 2020 Technical Rule amended the 2016 NSPS OOOOa to streamline 
the recordkeeping and reporting requirements for the VOC fugitive 
emissions standards. The amendments removed the requirement to report 
or keep certain records that the EPA determined were redundant or 
unnecessary; in some instances, the rule replaced those requirements or 
added new requirements that could better demonstrate and ensure 
compliance, in particular where the underlying requirement was also 
amended (e.g., repair requirements). These amendments reflect 
consideration of the public comments received on the proposal for that 
rulemaking. The purpose and function of the recordkeeping and reporting 
requirements are equally applicable to methane and VOCs, and therefore, 
are not pollutant specific. For the same reasons the EPA streamlined 
these requirements in the 2020 Technical Rule,\186\ the EPA is 
proposing to apply these streamlined recordkeeping and reporting 
requirements for methane

[[Page 63166]]

emissions from sources subject to NSPS OOOOa.
---------------------------------------------------------------------------

    \186\ See 85 FR 57415 (September 15, 2020).
---------------------------------------------------------------------------

    For each collection of fugitive emissions components located at a 
well site or compressor station, the following amendments were made to 
the recordkeeping and reporting requirements in the 2020 Technical 
Rule:
     Revised the requirements in 40 CFR 60.5397a(d)(1) to 
require inclusion of procedures that ensure all fugitive emissions 
components are monitored during each survey within the monitoring plan.
     Removed the requirement to maintain records of a digital 
photo of each monitoring survey performed, captured from the OGI 
instrument used for monitoring when leaks are identified during the 
survey because the records of the leaks provide proof of the survey 
taking place.
     Removed the requirement to maintain records of the number 
and type of fugitive emissions components or digital photo of fugitive 
emissions components that are not repaired during the monitoring survey 
once repair is completed and verified with a resurvey.
     Required records of the date of first attempt at repair 
and date of successful repair.
     Revised reporting to specify the type of site (i.e., well 
site or compressor station) and when the well site changes status to a 
wellhead-only well site.
     Removed requirement to report the name or ID of operator 
performing the monitoring survey.
     Removed requirement to report the number and type of 
difficult-to-monitor and unsafe-to-monitor components that are 
monitored during each monitoring survey.
     Removed requirement to report the ambient temperature, sky 
conditions, and maximum wind speed.
     Removed requirement to report the date of successful 
repair.
     Removed requirement to report the type of instrument used 
for resurvey.
5. AMEL
    The 2020 Technical Rule made the following amendments to the 
provisions associated with applications for use of an AMEL for VOC work 
practice standards for well completions, reciprocating compressors, and 
the collection of fugitive emissions components located at well sites 
and gathering and boosting compressor stations. For the same reasons 
provided in the 2020 Technical Rule and reiterated below, the EPA is 
proposing to similarly amend the 2016 NSPS OOOOa provisions associated 
with applications for use of an AMEL for methane work practice 
standards at well sites and gathering and boosting compressor stations 
and VOC and methane work practice standards at compressor stations in 
the transmission and storage segment.
    The 2020 Technical Rule amended the AMEL application requirements 
to help streamline the process for evaluation and possible approval of 
advanced measurement technologies. The amendments included allowing 
submission of applications by, among others, owners and operators of 
affected facilities, manufacturers or vendors of leak detection 
technologies, or trade associations. The 2020 Technical Rule ``allows 
any person to submit an application for an AMEL under this provision.'' 
85 FR 57422 (September 15, 2020). However, the 2020 Technical Rule, 
like the 2016 NSPS OOOOa still requires that the application include 
sufficient information to demonstrate that the AMEL achieves emission 
reductions at least equivalent to the work practice standards in the 
rule. To that end, the 2020 Technical Rule ``requires applications for 
these AMEL to include site-specific information to demonstrate 
equivalent emissions reductions, as well as site-specific procedures 
for ensuring continuous compliance.'' Id. At a minimum, the application 
should include field data that encompass seasonal variations, which may 
be supplemented with modeling analyses, test data, and/or other 
documentation. The specific work practice(s), including performance 
methods, quality assurance, the threshold that triggers action, and the 
mitigation thresholds are also required as part of the AMEL 
application. For example, for a technology designed to detect fugitive 
emissions, information such as the detection criteria that indicate 
fugitive emissions requiring repair, the time to complete repairs, and 
any methods used to verify successful repair would be required.
    Since the 2020 Technical Rule changes to the AMEL provisions in the 
2016 NSPS OOOOa are procedural in the sense that they mostly speak to 
the ``minimum information that must be included in each application in 
order for the EPA to make a determination of equivalency and, thus, be 
able to approve an alternative'' the EPA believes that it is 
appropriate to retain those amendments. 85 FR 57422 (September 15, 
2020). If finalized, the application must demonstrate equivalence as 
explained above for both the reduction of methane and VOC emissions. 
Because the 2020 Technical Rule amended only the VOC standards in the 
2016 NSPS OOOOa, and since EPA believes that basis for promulgation of 
this provision for AMEL applications equally applies to work practices 
standards for methane emissions at facilities in the production and 
processing segments and VOC and methane emissions at facilities in the 
transmission and storage segment, the EPA is proposing to apply these 
application requirements for all applicants seeking an AMEL for the 
methane and VOC work practice standards in NSPS OOOOa.
6. Alternative Fugitive Emissions Standards Based on Equivalent State 
Programs
    The 2020 Technical Rule added a new section (at 40 CFR 60.5399a) 
which served two purposes. First, the new section outlined procedures 
for State, local, and Tribal authorities to seek the EPA's approval of 
their VOC fugitive emissions standards at well sites and gathering and 
boosting compressor stations as an alternative to the Federal 
standards. Second, the new section approved specific voluntary 
alternative standards for six States. For the same reasons provided in 
the 2020 Technical Rule and reiterated below, the EPA is proposing to 
similarly allow this new section to apply to fugitive emissions 
standards for methane fugitive emissions at well sites and gathering 
and boosting compressor stations, and VOC and methane fugitive 
emissions at compressor stations in the transmission and storage 
segment.
    The 2020 Technical Rule added this new section in part to allow the 
use of specific alternative fugitive emissions standards for VOC 
emissions for six State fugitive emissions programs that the EPA had 
concluded were at least equivalent to the fugitive emissions monitoring 
and repair requirements at 40 CFR 60.5397a(e), (f), (g), and (h) as 
amended in that rule.\187\ These approved alternative fugitive 
emissions standards may be used for certain individual well sites or 
gathering and boosting compressor stations that are subject to VOC 
fugitive emissions monitoring and repair so long as the source complies 
with specified Federal requirements applicable to each approved 
alternative State program and included in 40 CFR 60.5399a(f) through 
(n). For example, a well site that is subject to the requirements of 
Pennsylvania General Permit 5A, section G, effective August 8, 2018, 
could choose to comply with those

[[Page 63167]]

standards in lieu of the monitoring, repair, recordkeeping, and 
reporting requirements in the NSPS for fugitive emissions at well 
sites. However, in that example, the owner or operator must develop and 
maintain a fugitive emissions monitoring plan, as required in 40 CFR 
60.5397a(c) and (d), and must monitor all of the fugitive emissions 
components, as defined in 40 CFR 60.5430a, regardless of the components 
that must be monitored under the alternative standard (i.e., under 
Pennsylvania General Permit 5A, Section G in the example). 
Additionally, the facility choosing to use the EPA-approved alternative 
standard must submit, as an attachment to its annual report for NSPS 
OOOOa, the report that is submitted to its State in the format 
submitted to the State, or the information required in the report for 
NSPS OOOOa if the State report does not include site-level monitoring 
and repair information. If a well site is located in the State but is 
not subject to the State requirements for monitoring and repair (i.e., 
not obligated to monitor or repair fugitive emissions), then the well 
site must continue to comply with the Federal requirements of the NSPS 
at 40 CFR 60.5397a in its entirety.
---------------------------------------------------------------------------

    \187\ See memorandum, ``Equivalency of State Fugitive Emissions 
Programs for Well Sites and Compressor Stations to Final Standards 
at 40 CFR part 60, subpart OOOOa,'' located at Docket ID No. EPA-HQ-
OAR-2017-0483. January 17, 2020.
---------------------------------------------------------------------------

    In addition to providing the EPA-approved voluntary alternative 
fugitive emissions standards for well sites and gathering and boosting 
compressor stations located in California, Colorado, Ohio, 
Pennsylvania, and Texas, and well sites in Utah, the amendments in the 
2020 Technical Rule provide application requirements to request the EPA 
approval of an alternative fugitive emissions standards as State, 
local, and Tribal programs continue to develop. Applications for the 
EPA approval of alternative fugitive emissions standards based on 
State, local, or Tribal programs may be submitted by any interested 
person, including individuals, corporations, partnerships, 
associations, States, or municipalities. Similar to the application 
process for AMEL for advanced measurement technologies, the application 
must include sufficient information to demonstrate that the alternative 
fugitive emissions standards achieve emissions reductions at least 
equivalent to the fugitive emissions monitoring and repair requirements 
in the Federal NSPS. At a minimum, the application must include the 
monitoring instrument, monitoring procedures, monitoring frequency, 
definition of fugitive emissions requiring repair, repair requirements, 
recordkeeping, and reporting requirements. If any of the sections of 
the State regulations or permits approved as alternative fugitive 
emissions standards are changed at a later date, the State must follow 
the procedures outlined in 40 CFR 60.5399a to apply for a new 
evaluation of equivalency.
    As part of the 2018 proposed rule (83 FR 52056, October 15, 2018) 
that resulted in the 2020 Technical Rule, the EPA evaluated the 
specific State programs for both methane and VOC emissions at well 
sites, gathering and boosting compressor stations, and compressor 
stations in the transmission and storage segment as discussed in detail 
in a memorandum to that docket evaluating the equivalency of State 
fugitive emissions programs.\188\ The EPA is now proposing that all 
well sites and compressor stations located in and subject to the 
specified State regulations in 40 CFR 60.5399a may utilize these 
alternative fugitive emissions standards for both methane and VOC 
fugitive emissions. In the 2020 Technical Rule the EPA concluded that 
these monitoring, repair, recordkeeping, and reporting requirements 
were equivalent to the same types of requirements in the 2016 NSPS 
OOOOa for VOC at well sites and gathering and boosting compressor 
stations. See 85 FR 57424. The monitoring instrument (i.e., OGI or EPA 
Method 21) will detect, at the same time, both methane and VOC 
emissions without speciating these emissions. Therefore, detection of 
one of these pollutants is also detection of the other pollutant. For 
the same reasons provided in the 2020 Technical Rule, and explained in 
the associated State equivalency memos, the EPA proposes to find these 
same State fugitive emissions standards (as specified in 40 CFR 
60.5399a(f) through (n)) equivalent to the specified Federal methane 
fugitive emissions standards for well sites and gathering and boosting 
stations, and the methane and VOC fugitive emissions standards for 
compressor stations in the transmission and storage segment. The EPA is 
also proposing to allow State, local, and Tribal agencies to apply for 
the EPA approval of their fugitives monitoring program as an 
alternative to the Federal NSPS for methane. Put another way, the EPA 
is proposing to include methane throughout 40 CFR 60.5399a.
---------------------------------------------------------------------------

    \188\ See Docket ID Nos. EPA-HQ-OAR-2017-0483-0041 and EPA-HQ-
OAR-2017-0483-2277.
---------------------------------------------------------------------------

    The EPA recognizes that the determinations of equivalence included 
in the 2020 Technical Rule were based on the fugitive emissions 
monitoring requirements that existed at that time for the 2016 NSPS 
OOOOa which, based on other changes in the 2020 Technical Rule, 
included an exemption from monitoring for low production well sites and 
required semiannual monitoring at gathering and boosting compressor 
stations. As explained above, the EPA is proposing to repeal both of 
those changes, and require semiannual monitoring at all well sites, 
including those with low production, and quarterly monitoring at 
gathering and boosting compressor stations. These proposed changes to 
the 2016 NSPS OOOOa fugitive emissions requirements do not impact the 
EPA's conclusion that the six previously approved alternative State 
programs are equivalent to the Federal standards. Even so, the EPA is 
proposing regulatory changes within the alternative State program 
provisions in 2016 NSPS OOOOa to account for these proposed changes to 
the Federal standards. See the redline version of regulatory text in 
the docket at Docket ID No. EPA-HQ-OAR-2021-0317. These changes are 
intended to ensure that the previously approved alternative State 
programs continue to maintain equivalency with the Federal standards if 
NSPS OOOOa is revised as proposed here. With these changes, the EPA 
continues to find that the alternative State programs that were 
previously approved are still equivalent with, if not better than, the 
Federal requirements.
7. Onshore Natural Gas Processing Plants
a. Capital Expenditure
    The 2020 Technical Rule made certain amendments to the 2016 NSPS 
OOOOa definition of capital expenditure as it relates to modifications 
for VOC LDAR requirements at onshore natural gas processing plants. For 
the same reasons provided in the 2020 Technical Rule and reiterated 
below, the EPA is proposing to similarly amend this definition as it 
relates to the methane LDAR requirements at onshore natural gas 
processing plants.
    The 2020 Technical Rule amended the definition of ``capital 
expenditure'' at 40 CFR 50.5430a by replacing the equation used to 
determine the percent of replacement cost, ``Y.'' This amendment was 
necessary because, as originally promulgated, the equation for 
determining ``Y'' would result in an error, thus, making it difficult 
to determine whether a capital expenditure had occurred using the NSPS 
OOOOa equation. The 2020 Technical Rule replaced the equation with an 
equation that utilizes the consumer price indices, ``CPI'' because it 
more appropriately reflects inflation than the original equation. 
Specifically, the equation for ``Y'' as amended in the

[[Page 63168]]

2020 Technical Rule, is based on the CPI, where ``Y'' equals the CPI of 
the date of construction divided by the most recently available CPI of 
the date of the project, or ``CPIN/CPIPD.'' 
Further, the 2020 Technical Rule specifies that the ``annual average of 
the CPI for all urban consumers (CPI-U), U.S. city average, all items'' 
must be used for determining the CPI of the year of construction, and 
the ``CPI-U, U.S. city average, all items'' must be used for 
determining the CPI of the date of the project. This amendment 
clarified that the comparison of costs is between the original date of 
construction of the process unit (the affected facility) and the date 
of the project which adds equipment to the process unit. For these same 
reasons, the EPA is proposing that the definition of ``capital 
expenditure,'' as amended by the 2020 Technical Rule, also be used to 
determine whether modification had occurred and thus triggers the 
applicability of the methane LDAR requirements at onshore natural gas 
processing plants in the 2016 NSPS OOOOa.
b. Initial Compliance Period
    The 2020 Technical Rule amended the VOC standards for onshore 
natural gas processing plants to specify that the initial compliance 
deadline for the equipment leak standards is 180 days. The EPA is 
proposing to apply this clarification to the initial compliance 
deadline with the methane standards for equipment leaks at onshore 
natural gas processing plants.
    As explained in the 2020 Technical Rule, the EPA added a provision 
requiring compliance ``as soon as practicable, but no later than 180 
days after initial startup'' because that provision was in the NSPS for 
equipment leaks of VOC at onshore natural gas processing plants when it 
was first promulgated, specifically at 40 CFR 60.632(a) of part 60, 
subpart KKK (NSPS KKK). 85 FR 57408. This provision at 40 CFR 60.632(a) 
provides up to 180 days to come into compliance with NSPS KKK. In 2012, 
the EPA revised the standards in NSPS KKK with the promulgation of NSPS 
OOOO \189\ by lowering the leak definition for valves from 10,000 ppm 
to 500 ppm and requiring the monitoring of connectors. 77 FR 49490, 
49498. While the EPA did not mention that it was also amending the 180-
day compliance deadline in NSPS OOOO, this provision at 40 CFR 
60.632(a) was not included in NSPS OOOO and, in turn, was not included 
in NSPS OOOOa. During the rulemaking for NSPS OOOOa, the EPA declined a 
request to include this provision at 40 CFR 60.632(a) in NSPS OOOOa, 
explaining that such inclusion was not necessary because NSPS OOOOa 
already includes by reference a similar provision (i.e., 40 CFR 60.482-
1a(a)) which requires each owner or operator to ``demonstrate 
compliance . . . within 180 days of initial startup,'' 80 FR 56593, 
56647-8. However, in reassessing the issue during the rulemaking for 
the 2020 Technical Rule, the EPA noted that NSPS KKK includes both the 
provision in 40 CFR 60.632(a) and 40 CFR 60.482-1(a), which contains a 
provision that is the same as the one described above at 40 CFR 60.482-
1a(a), thus suggesting that 40 CFR 60.632(a) is not redundant or 
unnecessary. In fact, the absence of this provision in NSPS OOOO/OOOOa 
raised a question as to whether compliance is required within 30 days 
for equipment that is required to be monitored monthly. To clarify this 
confusion and remain consistent with NSPS KKK, the 2020 Technical Rule 
amended NSPS OOOOa to reinstate this provision at 40 CFR 60.632(a). For 
the same reasons explained above, the EPA is proposing to similarly 
apply this provision to compliance with methane standards for the 
equipment leaks at onshore natural gas processing plants.
---------------------------------------------------------------------------

    \189\ ``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.''
---------------------------------------------------------------------------

    This provision clarifies that monitoring must begin as soon as 
practicable, but no later than 180 days after the initial startup of a 
new, modified, or reconstructed process unit at an onshore natural gas 
processing plant. Once started, monitoring must continue with the 
required schedule. For example, if pumps are monitored by month 3 of 
the initial startup period, then monthly monitoring is required from 
that point forward. This initial compliance period is different than 
the compliance requirements for newly added pumps and valves within a 
process unit that is already subject to a LDAR program. Initial 
monitoring for those newly added pumps and valves is required within 30 
days of the startup of the pump or valve (i.e., when the equipment is 
first in VOC service).
8. Technical Corrections and Clarifications
    The 2020 Technical Rule also revised the 2016 NSPS OOOOa for VOC 
emissions to include certain additional technical corrections and 
clarifications. In this action, the EPA is proposing to apply these 
same technical corrections and clarifications to the methane standards 
for production and processing segments and/or the methane and VOC 
standards for the transmission and storage segment in the 2016 NSPS 
OOOOa, as appropriate. Specifically, the EPA is proposing to:
     Revise 40 CFR 60.5385a(a)(1), 60.5410a(c)(1), 
60.5415a(c)(1), and 60.5420a(b)(4)(i) and (c)(3)(i) to clarify that 
hours or months of operation at reciprocating compressor facilities 
must be measured beginning with the date of initial startup, the 
effective date of the requirement (August 2, 2016), or the last rod 
packing replacement, whichever is latest.
     Revise 40 CFR 60.5393a(b)(3)(ii) to correctly cross-
reference paragraph (b)(3)(i) of that section.
     Revise 40 CFR 60.5397a(c)(8) to clarify the calibration 
requirements when Method 21 of appendix A-7 to part 60 is used for 
fugitive emissions monitoring.
     Revise 40 CFR 60.5397a(d)(3) to correctly cross-reference 
paragraphs (g)(3) and (4) of that section.
     Revise 40 CFR 60.5401a(e) to remove the word ``routine'' 
to clarify that pumps in light liquid service, valves in gas/vapor 
service and light liquid service, and pressure relief devices (PRDs) in 
gas/vapor service within a process unit at an onshore natural gas 
processing plant located on the Alaska North Slope are not subject to 
any monitoring requirements, whether the monitoring is routine or 
nonroutine.
     Revise 40 CFR 60.5410a(e) to correctly reference pneumatic 
pump affected facilities located at a well site as opposed to pneumatic 
pump affected facilities not located at a natural gas processing plant 
(which would include those not at a well site). This correction 
reflects that the 2016 NSPS OOOOa do not contain standards for 
pneumatic pumps at gathering and boosting compressor stations. 81 FR 
35850.
     Revise 40 CFR 60.5411a(a)(1) to remove the reference to 
paragraphs (a) and (c) of 40 CFR 60.5412a for reciprocating compressor 
affected facilities.
     Revise 40 CFR 60.5411a(d)(1) to remove the reference to 
storage vessels, as this paragraph applies to all the sources listed in 
40 CFR 60.5411a(d), not only storage vessels.
     Revise 40 CFR 60.5412a(a)(1) and (d)(1)(iv) to clarify 
that all boilers and process heaters used as control devices on 
centrifugal compressors and storage vessels must introduce the vent 
stream into the flame zone. Additionally, revise 40 CFR 
60.5412a(a)(1)(iv) and (d)(1)(iv)(D) to clarify that the vent stream 
must be introduced with the primary fuel or as the primary fuel to

[[Page 63169]]

meet the performance requirement option. This is consistent with the 
performance testing exemption in 40 CFR 60.5413a and continuous 
monitoring exemption in 40 CFR 60.5417a for boilers and process heaters 
that introduce the vent stream with the primary fuel or as the primary 
fuel.
     Revise 40 CFR 60.5412a(c) to correctly reference both 
paragraphs (c)(1) and (2) of that section, for managing carbon in a 
carbon adsorption system.
     Revise 40 CFR 60.5413a(d)(5)(i) to reference fused silica-
coated stainless steel evacuated canisters instead of a specific name 
brand product.
     Revise 40 CFR 60.5413a(d)(9)(iii) to clarify the basis for 
the total hydrocarbon span for the alternative range is propane, just 
as the basis for the recommended total hydrocarbon span is propane.
     Revise 40 CFR 60.5413a(d)(12) to clarify that all data 
elements must be submitted for each test run.
     Revise 40 CFR 60.5415a(b)(3) to reference all applicable 
reporting and recordkeeping requirements.
     Revise 40 CFR 60.5416a(a)(4) to correctly cross-reference 
40 CFR 60.5411a(a)(3)(ii).
     Revise 40 CFR 60.5417a(a) to clarify requirements for 
controls not specifically listed in paragraph (d) of that section.
     Revise 40 CFR 60.5422a(b) to correctly cross-reference 40 
CFR 60.487a(b)(1) through (3) and (b)(5).
     Revise 40 CFR 60.5422a(c) to correctly cross-reference 40 
CFR 60.487a(c)(2)(i) through (iv) and (c)(2)(vii) through (viii).
     Revise 40 CFR 60.5423a(b) to simplify the reporting 
language and clarify what data are required in the report of excess 
emissions for sweetening unit affected facilities.
     Revise 40 CFR 60.5430a to remove the phrase ``including 
but not limited to'' from the ``fugitive emissions component'' 
definition. During the 2016 NSPS OOOOa rulemaking, the EPA stated in a 
response to comment that this phrase is being removed,\190\ but did not 
do so in that rulemaking.
---------------------------------------------------------------------------

    \190\ See Docket ID Item No. EPA-HQ-OAR-2010-0505-7632, Chapter 
4, page 4-319.
---------------------------------------------------------------------------

     Revise 40 CFR 60.5430a to remove the phrase ``at the sales 
meter'' from the ``low pressure well'' definition to clarify that when 
determining the low-pressure status of a well, pressure is measured 
within the flow line, rather than at the sales meter.
     Revise Table 3 of 40 CFR part 60, subpart OOOOa, to 
correctly indicate that the performance tests in 40 CFR 60.8 do not 
apply to pneumatic pump affected facilities.
     Revise Table 3 of 40 CFR part 60, subpart OOOOa, to 
include the collection of fugitive emissions components at a well site 
and the collection of fugitive emissions components at a compressor 
station in the list of exclusions for notification of reconstruction.
     Revise 40 CFR 60.5393a(f), 60.5410a(e)(8), 60.5411a(e), 
60.5415a(b) introductory text and (b)(4), 60.5416a(d), and 60.5420a(b) 
introductory text and (b)(13), and introductory text in 40 CFR 60.5411a 
and 60.5416a, to remove language associated with the administrative 
stay we issued under section 307(d)(7)(B) of the CAA in ``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). The administrative stay was vacated by the D.C. 
Circuit on July 3, 2017.

XI. Summary of Proposed NSPS OOOOb and EG OOOOc

    This section presents a summary of the specific NSPS standards and 
EG presumptive standards the EPA is proposing for various types of 
equipment and emission points. More details of the rationale for these 
standards and requirements, including alternative compliance options 
and exemptions to the standards, are provided in section XII of this 
preamble and the TSD for this action in the public docket. As stated in 
section I, the EPA intends to provide draft regulatory text for the 
proposed NSPS OOOOb and EG OOOOc in a supplemental proposal.

A. Fugitive Emissions From Well Sites and Compressor Stations

    Fugitive emissions are unintended emissions that can occur from a 
range of equipment at any time. The magnitude of these emissions can 
also vary widely. The EPA has historically targeted fugitive emissions 
from the Crude Oil and Natural Gas source category through ground-based 
component level monitoring using OGI, or alternatively, EPA Method 21.
    The EPA is proposing the following monitoring requirements and 
presumptive standards for the collection of fugitive emissions 
components located at well sites and compressor stations. Additional 
details for the proposed standards and proposed presumptive standards 
are included in the following subsections. Information received through 
the various solicitations in this section may be used to evaluate if a 
change in the BSER is appropriate from the proposed requirements below, 
specifically consideration of alternative measurement technologies as 
the BSER. Any potential changes would be addressed through a 
supplemental proposal.
     Well sites with total site-level baseline methane 
emissions less than 3 tpy: Demonstration, based on a site-specific 
survey, that actual emissions are reflected in the baseline methane 
emissions calculation,
     Well sites with total site-level baseline methane 
emissions of 3 tpy or greater: Quarterly OGI or EPA Method 21 
monitoring,
     (Co-proposal) Well sites with total site-level baseline 
methane emissions of 3 tpy or greater and less than 8 tpy: Semiannual 
OGI or EPA Method 21 monitoring,
     (Co-proposal) Well sites with total site-level baseline 
methane emissions of 8 tpy or greater: Quarterly OGI or EPA Method 21 
monitoring,
     Compressor stations: Quarterly OGI or EPA Method 21 
monitoring,
     Well sites and compressor stations located on the Alaska 
North Slope: Annual monitoring, with separate initial monitoring 
requirements, and
     Alternative screening approach for all well sites and 
compressor stations: Bimonthly screening surveys using advanced 
measurement technology and annual OGI or EPA Method 21 monitoring at 
each individual well site or compressor station.
1. Definition of Fugitive Emissions Component
    A key factor in evaluating how to target fugitive emissions is 
clearly identifying the emissions of concern and the sources of those 
emissions. In the 2016 NSPS OOOOa, the EPA defined ``fugitive emissions 
component'' as ``any component with the potential to emit methane and 
VOCs'' and included several specific component types, ranging from 
valves and connectors, to openings on controlled storage vessels that 
were not regulated under NSPS OOOOa.
    However, data shows that the universe of components with potential 
for fugitive emissions is broader than the illustrative list included 
in the 2016 NSPS OOOOa, and that the majority of the largest emissions 
events occur from a subset of components that may not have been clearly 
included in the definition. Therefore, the EPA is proposing a new 
definition for ``fugitive emissions component'' to provide clarity that 
these sources of large emission events are covered.

[[Page 63170]]

    ``Fugitive emissions component'' is proposed to be any component 
that has the potential to emit fugitive emissions of methane and VOC at 
a well site or compressor station, including valves, connectors, PRDs, 
open-ended lines, flanges, all covers and closed vent systems, all 
thief hatches or other openings on a controlled storage vessel, 
compressors, instruments, meters, natural gas-driven pneumatic 
controllers or natural gas-driven pumps. However, natural gas 
discharged from natural gas-driven pneumatic controllers or natural 
gas-driven pumps are not considered fugitive emissions if the device is 
operating properly and in accordance with manufacturers specifications. 
Control devices, including flares, with emissions resulting from the 
device operating in a manner that is not in full compliance with any 
Federal rule, State rule, or permit, are also considered fugitive 
emissions components. This proposed definition includes the same 
components that were included in the 2016 NSPS OOOOa and adds sources 
of large emissions, such as malfunctioning controllers or control 
devices.
    The inclusion of specific component types in this proposed 
definition would allow the use of OGI, EPA Method 21, or an alternative 
screening technology to identify emissions that would either be 
repaired (i.e., leaks) or have a root cause analysis with corrective 
action (e.g., malfunctioning control device, unintentional gas carry 
through, venting from covers and openings on a controlled storage 
vessel, or malfunctioning natural gas-driven pneumatic controllers). 
Further, we are proposing that where a CVS is used to route emissions 
from an affected facility (i.e., centrifugal or reciprocating 
compressor, pneumatic pump, or storage vessel), the owner or operator 
would demonstrate there are no detectable emissions from the covers and 
CVS through the OGI (or EPA Method 21) monitoring conducted during the 
fugitive emissions survey. Where emissions are detected, corrective 
actions to complete all necessary repairs as soon as practicable would 
be required, and the emissions would be considered a potential 
violation of the no detectable emissions standard. In the case of a 
malfunction or operational upset of a control device or the equipment 
itself, where emissions are not expected to occur if the equipment is 
operating in compliance with the standards of the rule, this proposal 
would require the owner or operator to conduct a root cause analysis to 
determine why the emissions are present, take corrective action to 
complete all necessary repairs as soon as practicable and prevent 
reoccurrence of emissions, and report the malfunction or operational 
upset as a potential violation of the underlying standards for the 
source of the emissions. We are soliciting comment on whether to 
include the option to continue utilizing monthly AVO surveys as 
demonstrations of no detectable emissions from a CVS but are not 
proposing that option specifically. Because the EPA is proposing both 
NSPS and EG in this action, we anticipate that CVS associated with 
controlled pneumatic pumps will be located at well sites subject to 
fugitive emissions monitoring. Therefore, we do not believe the monthly 
AVO option is necessary. However, we are soliciting comment on whether 
there are circumstances where a CVS associated with a controlled 
pneumatic pump is located at a well site not otherwise subject to 
fugitive emissions monitoring and where OGI (or EPA Method 21) would be 
an additional burden.
    The EPA is soliciting comment on this proposed definition of 
``fugitive emissions component,'' including any additional components 
or characterization of components that should be included. Further, we 
are soliciting comment on the use of the fugitive emissions survey to 
identify malfunctions and other large emission sources where the 
equipment is not operating in compliance with the underlying standards, 
including the proposed requirement to perform a root cause analysis and 
to take corrective action to mitigate and prevent future malfunctions.
2. Fugitive Emissions From Well Sites
    The current NSPS for reducing fugitive VOC and methane emissions at 
well sites requires semiannual monitoring, except that a low production 
well site (one that produces at or below 15 barrels of oil equivalent 
(boe) per day) is exempt from VOC monitoring. As explained in section 
X.A.1, we are proposing to remove that exemption from NSPS OOOOa, as we 
have concluded that exemption was not justified by the underlying 
record and does not represent BSER. Further, based on our revised BSER 
analysis, which is summarized in section XII.A.1.a, the EPA is 
proposing updated standards for reducing fugitive VOC and methane 
emissions from the collection of fugitive emissions components located 
at new, modified, or reconstructed well sites (under the newly proposed 
NSPS OOOOb). Also, for the reasons discussed in section XII.A.2, the 
EPA is proposing to determine that the BSER analysis supports a 
presumptive standard for reducing methane emissions from the collection 
of fugitive emissions components located at existing well sites (under 
the newly proposed EG OOOOc) that is the same as what we are proposing 
for the NSPS (for NSPS OOOOb). Provided below is a summary of the 
proposed updated NSPS and the proposed EG.
a. NSPS OOOOb
    For new, modified, or reconstructed sources, we are proposing a 
fugitive emissions monitoring and repair program that includes 
monitoring for fugitive emissions with OGI in accordance with the 
proposed 40 CFR part 60, appendix K (``appendix K''), which is included 
in this action and outlines the proposed procedures that must be 
followed to identify emissions using OGI.\191\ We are also proposing 
that EPA Method 21 may be used as an alternative to OGI monitoring. We 
are further proposing that monitoring must begin within 90 days of 
startup of production (or startup of production after modification).
---------------------------------------------------------------------------

    \191\ ``Determination of Volatile Organic Compound and 
Greenhouse Gas Leaks Using Optical Gas Imaging'' located at Docket 
ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------

    Unlike in NSPS OOOOa which, as amended by the 2020 Technical Rule, 
set VOC monitoring frequency based on production level, the EPA is 
proposing that the OGI monitoring frequency be based on the site-level 
methane baseline emissions,\192\ as determined, in part, through 
equipment/component count emission factors. The EPA is proposing the 
calculation of the total site-wide methane emissions, including 
fugitive emissions from components, emissions from natural gas-driven 
pneumatic controllers, natural gas-driven pneumatic pumps, storage 
vessels, as well as other regulated and non-regulated emission sources. 
Specifically, we are proposing that owners or operators would calculate 
the site-level baseline methane emissions using a combination of 
population-based emission factors and storage vessel emissions. 
Further, the EPA proposes this calculation would be repeated every time 
equipment is added to or removed from the site. For each natural gas-
driven pneumatic pump, continuous bleed natural gas-driven pneumatic

[[Page 63171]]

controller, and intermittent bleed natural gas-driven pneumatic 
controller located at the well site, the owner or operator would apply 
the population emission factors for all components found in Table W-1A 
of GHGRP subpart W. For each piece of major production and processing 
equipment and each wellhead located at the well site, the owner or 
operator would first apply the default average component counts for 
major equipment found in Table W-1B and Table W-1C of GHGRP subpart W, 
and then apply the component-type emission factors for the population 
of valves, connectors, open-ended lines, and PRVs found in Table 2-8 of 
the 1995 Emissions Protocol.\193\ Finally, the owner or operator would 
use the calculated potential methane emissions after applying control 
(if applicable) for each storage vessel tank battery located at the 
well site. The sum of the emissions estimated for all equipment at the 
site would be used as the baseline methane emissions for determining 
the applicable monitoring frequency. The EPA proposes to use the 
default population emission factors found in Table W-1A of GHGRP 
subpart W and the default average component counts for major equipment 
found in Tables W-1B and W-1C of GHGRP subpart W because they are well-
vetted emission and activity factors used by the Agency. The EPA is not 
incorporating these emission factors directly into the proposed NSPS 
OOOOb or EG OOOOc because they could be the subject of future GHGRP 
subpart W revisions, and if revised, those revisions would be relevant 
to this calculation. For the individual components (e.g., valves and 
connectors), the EPA proposes to rely on the component-type emission 
factors found in Table 2-8 of the 1995 Emissions Protocol for purposes 
of quantifying emissions from major production and processing equipment 
and each wellhead located at the well site because these data have been 
relied upon in previous rulemakings for this sector, have been the 
subject of extensive public comment, and the EPA has determined that 
they are appropriate to use for purposes of this action.
---------------------------------------------------------------------------

    \192\ As shown in the TSD, the EPA analyzed the monitoring 
frequency for both methane and VOC under both the single pollutant 
approach and the multipollutant approach. Because the composition of 
gas at a well site is predominantly methane (approximately 70 
percent), a methane threshold represents the lowest threshold that 
is cost effective to control both VOC and methane emissions.
    \193\ EPA, Protocol for Equipment Leak Emission Estimates, EPA-
453/R-95-017, November 1995.
---------------------------------------------------------------------------

    The EPA requests comment on whether the proposed methodologies for 
calculating site-level baseline methane emissions are appropriate for 
these emission sources, and if not, what methodologies would be more 
appropriate. Specifically, the EPA recognizes the proposed calculation 
methodology assumes all equipment is operating as designed (e.g., 
controlled storage vessels with all vapors routed to a control that is 
actually achieving 95 percent reduction or greater). Therefore, we are 
soliciting comment on whether sites should use the uncontrolled PTE 
calculation for their storage vessels in their site-level baseline 
estimate to account for times when these vessels are not operating as 
designed, which is a known cause of large emission events of concern. 
Further, to that point, the EPA is soliciting comment on how to develop 
a factor that could be applied to the site-level baseline calculation 
that would account for large emission events, or any specific data that 
would provide a factor for these events. As we state throughout this 
preamble, large emission events are of specific concern and fugitive 
emissions monitoring is an effective tool for detecting these 
emissions, therefore, we acknowledge there is considerable interest 
from various stakeholders that these emission events are accounted for 
in our analyses. At this time, the EPA does not have enough information 
to develop a factor or determine how to best apply that factor. 
Information provided through this solicitation would allow us to 
consider additional revisions to this calculation methodology through a 
supplemental proposal.
    The EPA is also soliciting comment on whether providing direct 
major equipment population emission factors that can be combined with 
site-specific gas compositions would provide a more transparent and 
less burdensome means to develop the site-specific emissions estimates 
than using a combination of major equipment counts, specific component 
counts per major equipment, and component-level population emission 
factors. Furthermore, the EPA requests comment on whether site-level 
baseline methane emissions should be determined using a baseline 
emissions survey instead of the proposed methodology, and if so, what 
methodologies should be used to quantify emissions from the survey such 
as measurement or emission factors based on leaking component emission 
factors. The EPA also solicits comment on specific methodologies to 
support commenters' positions. The EPA also requests comment on whether 
there are additional production and processing equipment or emission 
sources that should be included in the site-level baseline methane 
emissions. For example, the EPA is aware that there could be emission 
sources such as engines, dehydrator venting, compressor venting, 
associated gas venting, and migration of gas outside of the wellbore at 
a well site. If such equipment or emission sources should be included 
in the site-level baseline, the EPA requests comment on methodologies 
for quantifying emissions for purposes of the baseline.
    Based on the analysis described in section XII.A.1, the potential 
for fugitive emissions is impacted more by the number and type of 
equipment at the site, and not by the volume of production. Therefore, 
the EPA believes it is more appropriate to use site-specific emissions 
estimates based on the number and type of equipment located at the 
individual site to determine the monitoring frequency. Table 13 
summarizes the proposed site-level baseline methane thresholds for the 
proposed monitoring frequencies, which according to our analysis would 
achieve the greatest cost-effective emission reductions.
    As noted below, the EPA solicits comment on all aspects of the 
proposed tiered approach to monitoring that is summarized in Table 13. 
Although we are proposing no routine OGI monitoring where site-level 
baseline methane emissions are below 3 tpy, the EPA is proposing to 
require these sites to demonstrate the actual emissions are accounted 
for in the calculation. This demonstration would include a survey, such 
as OGI, EPA Method 21 (including provisions for the use of a soap 
solution), or advanced measurement technologies. Given that this 
demonstration is designed to show actual emissions are below 3 tpy, and 
most survey techniques are not quantitative, the EPA anticipates that 
sources finding emissions will make repairs on equipment/components 
identified as leaking during the demonstration survey.
    The EPA acknowledges that the 2016 NSPS OOOOa and this proposal 
allow the use of EPA Method 21 as an alternative to OGI monitoring to 
detect fugitive emissions from the collection of fugitive emissions 
components under the proposed tiered approach to monitoring. However, 
as discussed in section XI.A.5, EPA Method 21 is not proposed as an 
alternative for follow-up OGI surveys under the proposed alternative 
screening approach using advanced measurement technologies when 
screening detects emissions. This is because EPA Method 21 is not able 
to find all sources of leaks and is therefore not an appropriate method 
for detection in these cases where large emissions events have been 
identified. Given this limitation, the EPA is soliciting comment on 
whether EPA Method 21 remains an appropriate

[[Page 63172]]

alternative to OGI for routine OGI surveys.

 Table 13--Proposed Well Site Monitoring Frequencies Based on Site-Level
                       Baseline Methane Emissions
------------------------------------------------------------------------
 Site-level baseline methane      Proposed OGI         Co-proposed OGI
     emissions threshold      monitoring frequency  monitoring frequency
------------------------------------------------------------------------
>0 and <3 tpy...............  No routine            No routine
                               monitoring required.  monitoring
                                                     required.
>=3 and <8 tpy..............  Quarterly...........  Semiannual.
>=8 tpy.....................  Quarterly...........  Quarterly.
------------------------------------------------------------------------

    Where quarterly monitoring is proposed, subsequent quarterly 
monitoring would occur at least 60 days apart. Where semiannual 
monitoring is co-proposed, subsequent semiannual monitoring would occur 
at least 4 months apart and no more than 7 months apart. We are 
proposing to retain the provision in the 2016 NSPS OOOOa that the 
quarterly monitoring may be waived when temperatures are below 0 [deg]F 
for two of three consecutive calendar months of a quarterly monitoring 
period.
    The EPA has previously required the use of OGI technology to detect 
fugitive emissions of methane and VOC from the oil and gas sector 
(i.e., well sites and compressor stations). However, the EPA had not 
developed a protocol for its use even though the EPA has previously 
mentioned the need for an OGI protocol during other rulemakings where 
OGI has been proposed for leak detection.\194\ In this document, the 
EPA is proposing a draft protocol for the use of OGI as appendix K to 
40 CFR part 60. The EPA notes that while this protocol is being 
proposed for use in the oil and gas sector, the applicability of the 
protocol is broader. The protocol is applicable to surveys of process 
equipment using OGI cameras in the entire oil and gas upstream and 
downstream sectors from production to refining to distribution where a 
subpart in those sectors references its use.
---------------------------------------------------------------------------

    \194\ The development of appendix K to 40 CFR part 60 was 
previously mentioned in both the proposal for the National Uniform 
Emission Standards for Storage Vessel and Transfer Operations, 
Equipment Leaks, and Closed Vent Systems and Control Devices; and 
Revisions to the National Uniform Emission Standards General 
Provisions (77 FR 17897, March 26, 2012) and the Petroleum Refinery 
Sector Risk and Technology Review and New Source Performance 
Standards (79 FR 36880, June 30, 2014).
---------------------------------------------------------------------------

    As part of the development of appendix K, the EPA conducted an 
extensive literature review on the technology development as well as 
observations on current application of OGI technology. Approximately 
150 references identify the technology, applications, and limitations 
of OGI. The EPA also commissioned multiple laboratory studies and OGI 
technology evaluations. Additionally, on November 9 and 10, 2020, the 
EPA held a virtual stakeholder workshop to gather input on development 
of a protocol for the use of OGI. The information obtained from these 
efforts was used to develop the TSD for appendix K, which provides 
technical analyses, experimental results, and other supplemental 
information used to evaluate and develop standardized procedures for 
the use of OGI technology in monitoring for fugitive emissions of VOCs, 
HAP, and methane from industrial environments.\195\
---------------------------------------------------------------------------

    \195\ Technical Support Document--Optical Gas Imaging Protocol 
(40 CFR part 60, Appendix K), available in the docket for this 
action.
---------------------------------------------------------------------------

    Appendix K outlines the proposed procedures that instrument 
operators must follow to identify leaks or fugitive emissions using a 
hand-held, field portable infrared camera. Additionally, appendix K 
contains proposed specifications relating to the required performance 
of qualifying infrared cameras, required operator training and 
verification, determination of an operating window for performing 
surveys, and requirements for a monitoring plan and recordkeeping. The 
EPA is requesting comment on all aspects of the draft OGI protocol 
being proposed as appendix K to 40 CFR part 60.\196\
---------------------------------------------------------------------------

    \196\ See appendix K in Docket ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------

    As mentioned in section X.B.4.f, we are proposing that, once 
fugitive methane emissions are detected during the OGI survey, a first 
attempt at repair must be made within 30 days of detecting the fugitive 
emissions, with final repair, including resurvey to verify repair, 
completed within 30 days after the first attempt. These proposed repair 
requirements with respect to methane fugitive emissions are the same as 
those made in the 2020 Technical Rule for VOC fugitive emissions (and 
proposed in section X.B.4.f for methane in this action). Because large 
emission events contribute disproportionately to emissions, the EPA is 
soliciting comment on how to structure a requirement that would tier 
repair deadlines based on the severity of the fugitive emissions 
identified during the OGI (or EPA Method 21) surveys. In order for such 
a structure to work, there would need to be a way to qualify which 
fugitive emissions are smaller and which are larger, as the initial 
monitoring with OGI will not provide this information. One approach 
could be to define broad categories of leaks and make assumptions about 
the magnitude of emissions for those broad categories. For example, an 
open thief hatch would be considered a very large leak due to the 
surface opening size, and it would need to be remedied on the tightest 
timeframe, whereas a leaking connector would be considered a small leak 
based on historical emissions factors and could be repaired on a more 
lenient timeframe. The EPA is soliciting comments on how this approach 
could be structured, particularly the types of leaks that would fall 
into each broad category and the appropriate repair timeframes for each 
of the categories. The EPA is also soliciting comment on other 
approaches that could also be implemented for repairing fugitive 
emissions in a tiered structure. Finally, we are proposing to retain 
the requirement for owners and operators to develop a fugitive 
emissions monitoring plan that covers all the applicable requirements 
for the collection of fugitive emissions components located at a well 
site and includes the elements specified in the proposed appendix K 
when using OGI.
    The affected facilities include well sites with major production 
and processing equipment, and centralized tank batteries. As in the 
2020 Technical Rule, the EPA is proposing to not include ``wellhead 
only well sites,'' as affected facilities when the well site is a 
wellhead only well site at the date it becomes subject to the rule. 
Based on the proposed site-level baseline methane emissions calculation 
methodology, wellhead only sites would only calculate emissions from 
fugitive components (e.g., valves, connectors, flanges, and open-ended 
lines) that are located on the wellhead. We believe

[[Page 63173]]

these sites would not exceed the 3 tpy threshold to require routine 
monitoring. However, unlike the 2020 Technical Rule, the EPA is 
proposing that when a well site later removes all major production and 
processing equipment such that it becomes a wellhead only well site, it 
must recalculate the emissions in order to determine if a different 
frequency is then required. In this proposal, the definitions for 
``wellhead only well site'' and ``well site'' would be the same as 
those finalized in the 2020 Technical Rule. Specifically, ``wellhead 
only well site'' means ``for purposes of the fugitive emissions 
standards, a well site that contains one or more wellheads and no major 
production and processing equipment.'' The term ``major production and 
processing equipment'' refers to ``reciprocating or centrifugal 
compressors, glycol dehydrators, heater/treaters, separators, and 
storage vessels collecting crude oil, condensate, intermediate 
hydrocarbon liquids, or produced water.'' The EPA is soliciting comment 
on whether any other equipment not included in this definition should 
be added in order to clearly specify what well sites are considered 
wellhead only sites. Specifically, the EPA is soliciting comment on the 
inclusion of natural gas-driven pneumatic controllers, natural gas-
driven pneumatic pumps, and pumpjack engines in the definition of 
``major production and processing equipment.'' A ``well site'' means 
one or more surface sites that are constructed for the drilling and 
subsequent operation of any oil well, natural gas well, or injection 
well. For purposes of the fugitive emissions standards, a well site 
includes a centralized production facility. Also, for purposes of the 
fugitive emissions standards, a well site does not include: (1) UIC 
Class II oilfield disposal wells and disposal facilities; (2) UIC Class 
I oilfield disposal wells; and (3) the flange immediately upstream of 
the custody meter assembly and equipment, including fugitive emissions 
components, located downstream of this flange.
    In addition to retaining the above definitions, the EPA is also 
proposing a new definition for ``centralized production facility'' for 
purposes of fugitive emissions requirements for well sites, where a 
``centralized tank battery'' is one or more permanent storage tanks and 
all equipment at a single stationary source used to gather, for the 
purpose of sale or processing to sell, crude oil, condensate, produced 
water, or intermediate hydrocarbon liquid from one or more offsite 
natural gas or oil production wells. This equipment includes, but is 
not limited to, equipment used for storage, separation, treating, 
dehydration, artificial lift, combustion, compression, pumping, 
metering, monitoring, and flowline. Process vessels and process tanks 
are not considered storage vessels or storage tanks. A centralized 
production facility is located upstream of the natural gas processing 
plant or the crude oil pipeline breakout station and is a part of 
producing operations. Additional discussion on centralized production 
facilities is included in section XI.L.
    The EPA is not proposing any change to the current definition of 
modification as it relates to fugitive emissions requirements at well 
sites or centralized production facilities. Specifically, modification 
occurs at a well site when: (1) A new well is drilled at an existing 
well site; (2) a well at an existing well site is hydraulically 
fractured; or (3) a well at an existing well site is hydraulically 
refractured. Similarly, modification occurs at a centralized production 
facility when (1) any of the actions above occur at an existing 
centralized production facility; (2) a well sending production to an 
existing centralized production facility is modified as defined above 
for well sites; or (3) a well site subject to the fugitive emissions 
standards for new sources removes all major production and processing 
equipment such that it becomes a wellhead only well site and sends 
production to an existing centralized production facility.
b. EG OOOOc
    For existing well sites (for EG OOOOc), we are proposing a 
presumptive standard that follows the same fugitive monitoring and 
repair program as for new sources. For the reasons discussed in section 
XII.A.2, the BSER analysis for existing sources supports proposing a 
presumptive standard for reducing methane emissions from the collection 
of fugitive emissions components located at existing well sites that is 
the same as what the EPA is proposing for new, reconstructed, or 
modified sources (for NSPS OOOOb). The EPA did not identify any factors 
specific to existing sources that would alter the analysis performed 
for new sources to make that analysis different for existing well 
sites. The EPA determined that the OGI technology, methane emission 
reductions, costs, and cost effectiveness discussed above for the 
collection of fugitive emissions components at new well sites are also 
applicable for the collection of fugitive emissions components at 
existing well sites. Further, the fugitive emissions requirements do 
not require the installation of controls on existing equipment or the 
retrofit of equipment, which can generally be an additional factor for 
consideration when determining the BSER for existing sources. 
Therefore, the EPA found is appropriate to use the analysis developed 
for the proposed NSPS OOOOb to also develop the BSER and proposed 
presumptive standards for the EG OOOOc.
    Based on the information available at this time, the EPA thinks the 
large number of existing well sites, many of which are not complex 
warrants soliciting comment on whether existing well sites (or a 
subcategory thereof) could have different emission profiles due to 
certain site characteristics or other factors that would suggest a 
different presumptive standard is appropriate. Further, we remain 
concerned about the burden of fugitive emissions monitoring 
requirements on small businesses. Therefore, we are requesting comment 
on regulatory alternatives for well sites that accomplish the stated 
objectives of the CAA and which minimize any significant economic 
impact of the proposed rule on small entities, including any 
information or data that pertain to the emissions impacts and costs of 
our proposal to remove the exemption from fugitive monitoring for well 
sites with low emissions, or would support alternative fugitive 
monitoring requirements for these sites. We are soliciting data that 
assess the emissions from low production well sites, and information on 
any factors that could make certain well sites less likely to emit VOC 
and methane, including geologic features, equipment onsite, production 
levels, and any other factors that could establish the basis for 
appropriate regulatory alternatives for these sites. Further, the EPA 
is aware there are a subset of existing well sites that are owned by 
individual homeowners, farmers, or companies with very few employees 
(well below the threshold defining a small business). For these owners, 
the EPA is concerned our analysis underestimates the actual burden 
imposed by these proposed standards. As an example, ownership may be 
limited to 1 or 2 wells located on an individual's property, for which 
the production is used for heating the home. The cost burden of 
conducting fugitive emissions surveys in this type of scenario has not 
fully be analyzed. Therefore, the EPA solicits comment and information 
that would allow us to

[[Page 63174]]

further evaluate the burden on the smallest companies to further 
propose appropriate standards at this subset (or other similar subsets) 
of well sites through a supplemental proposal.
    Finally, we are soliciting comment on all aspects of the proposed 
fugitive emissions requirements for both new and existing well sites, 
including whether we should use the tiering approach, whether the tiers 
we have defined are appropriate, and the monitoring requirements for 
each tier, including whether it would be cost-effective to monitor at 
more frequent intervals than proposed. The EPA may include revisions to 
this proposal for ground-based OGI monitoring at well sites if 
information is received that would warrant consideration of a different 
approach to establishing monitoring frequencies at well sites.
3. Fugitive Emissions from Compressor Stations
    The current NSPS for reducing fugitive emissions from the 
collection of fugitive emissions components located at a compressor 
station is a fugitive emissions monitoring and repair program requiring 
quarterly OGI monitoring.\197\ Based on our analysis, which is 
summarized in section XII.A.1.b, the EPA is proposing quarterly OGI 
monitoring requirement for both methane and VOC as it continues to 
reflect the BSER for reducing both emissions from fugitive components 
at new, modified, and reconstructed compressor stations. Likewise, the 
EPA is also proposing quarterly monitoring as a presumptive GHG 
standard (in the form of limitation on methane emissions) for the 
collection of fugitive emissions components located at existing 
compressor stations. The affected compressor stations include gathering 
and boosting, transmission, and storage compressor stations.
---------------------------------------------------------------------------

    \197\ Note that for gathering and boosting compressor stations, 
the EPA is proposing to rescind the 2020 Technical Rule amendment 
that changed the monitoring frequency to semiannual for VOC 
emissions. See section X.A.2 for more information.
---------------------------------------------------------------------------

a. NSPS OOOOb
    We are proposing that the quarterly monitoring using OGI be 
conducted in accordance with the proposed appendix K described above in 
section XI.A.2, which outlines procedures that must be followed to 
identify leaks using OGI. We are proposing to retain the current 
requirements that monitoring must begin within 90 days of startup of 
the station (or startup after modification), with subsequent quarterly 
monitoring occurring at least 60 days apart. Also, quarterly monitoring 
may be waived when temperatures are below 0 [deg]F for two of three 
consecutive calendar months of a quarterly monitoring period. We are 
also not proposing any change to the following repair-related 
requirements: Specifically, a first attempt at repair must be made 
within 30 days of detecting the fugitive emissions, with final repair, 
including resurvey to verify repair, completed within 30 days after the 
first attempt. In addition, owners and operators must develop a 
fugitive emissions monitoring plan that covers all the applicable 
requirements for the collection of fugitive emissions components 
located at a compressor station. In conjunction with the proposed 
requirement that monitoring be conducted in accordance with the 
proposed appendix K, we are proposing to require that the monitoring 
plan also include elements specified in the proposed appendix K when 
using OGI.
b. EG OOOOc
    For existing sources, we are proposing a presumptive standard that 
includes the same fugitive emissions monitoring and repair program as 
for new sources. For the reasons discussed in section XII.A.2, the BSER 
analysis for existing sources supports proposing a presumptive standard 
for reducing methane emissions from the collection of fugitive 
emissions components located at existing compressor stations that is 
the same as what the EPA is proposing for new, modified, or 
reconstructed sources (for NSPS OOOOb).
    Similar to well sites, we are soliciting comment on all aspects of 
the proposed quarterly monitoring for both new and existing compressor 
stations, including whether more frequent monitoring would be 
appropriate. We are also soliciting information on several additional 
topics. First, the EPA is soliciting comment and data to assess whether 
compressor stations should be subcategorized for the NSPS and/or the 
EG, which the EPA could consider through a supplemental proposal. For 
example, some industry stakeholders have asserted that station 
throughput directly correlates to the operating pressures, equipment 
counts, and condensate production, which would influence fugitive 
emissions at the station. They suggested that subcategorization based 
on design throughput capacity for the compressor station may be 
appropriate. We are specifically seeking information related to 
throughputs where fugitive emissions of methane are demonstrated to be 
minimal below a certain capacity. While this specific example was 
raised in the context of existing sources only, the EPA is also 
soliciting comment on whether new, modified, or reconstructed 
compressor stations could encounter the same issue and therefore 
warrant similar subcategorization.
    Next, for compressor stations, we are soliciting comment on delayed 
repairs by existing sources when parts are not readily available and 
must be special ordered. In comments submitted to the EPA as part of 
the stakeholder outreach conducted prior to this proposal, industry 
stakeholders stated that the EPA ``should acknowledge that existing 
sources are older pieces of equipment so there is a higher likelihood 
that replacement parts will not be readily available; therefore, a lack 
of available parts should be an appropriate cause to delay a repair.'' 
\198\ Industry stakeholders further explained that operators will need 
to special order replacement parts. Further, they stated in their 
comments that operators should be afforded 30 days to schedule the 
repair once they have received the replacement part. The EPA is 
soliciting comment and data to better understand the breadth of this 
issue with replacement parts for existing compressor stations. 
Additionally, we are soliciting comment on whether 30 days following 
receipt of the replacement part is appropriate for completing delayed 
repairs at existing compressor stations, whether there should be any 
limit on delays in repairs under these circumstances, and whether this 
compliance flexibility should be limited or disallowed based on the 
severity of the leak to be repaired.
---------------------------------------------------------------------------

    \198\ Document ID No. EPA-HQ-OAR-2021-0295-0033.
---------------------------------------------------------------------------

    We are also soliciting comment on the specific records that should 
be maintained and/or reported to justify delayed repairs as a result of 
part availability issues. Depending on the additional information 
received, the EPA may consider proposing changes to the proposed EG for 
compressor stations through a supplemental proposal.
    Finally, as discussed in section XI.A.2, the EPA is soliciting 
comment on whether the scheduling of repairs at compressor stations 
should be tiered based on severity of the emissions found. Please refer 
to section XI.A.3 for additional details on this solicitation for 
comment.
4. Well Sites and Compressor Stations on the Alaska North Slope
    For new, reconstructed, and modified well sites and compressor 
stations

[[Page 63175]]

located on the Alaska North Slope, based on the rationale provided in 
section X.B.4.c of this preamble, the EPA is proposing the same 
monitoring requirements as those in NSPS OOOOa (under newly proposed 
OOOOb). Also, the EPA is proposing to determine that the same technical 
infeasibility issues with weather conditions exist for existing well 
sites and compressor stations located on the Alaska North Slope. 
Therefore, the EPA is proposing a presumptive standard for reducing 
methane emissions from the collection of fugitive emissions components 
located at existing well sites and compressor stations located on the 
Alaska North Slope (under the newly proposed EG OOOOc) that is the same 
as what we are proposing for NSPS OOOOb.
    Specifically, the EPA is proposing to require annual monitoring of 
methane and VOC emissions at all well sites and compressor stations 
located on the Alaska North Slope, with subsequent annual monitoring at 
least 9 months apart but no more than 13 months apart. The EPA is also 
proposing to require that new, reconstructed, and modified well sites 
and compressor stations located on the Alaska North Slope that startup 
(initially, or after reconstruction or modification) between September 
and March to conduct initial monitoring of methane and VOC fugitive 
emissions within 6 months of startup, or by June 30, whichever is 
later. Finally, the EPA is proposing to require that new, 
reconstructed, and modified well sites and compressor stations located 
on the Alaska North Slope that startup (initially, or after 
reconstruction or modification) between April and August to conduct 
initial monitoring of methane and VOC fugitive emissions within 90 days 
of startup.
5. Alternative Screening Using Advanced Measurement Technologies
    For new, modified, or reconstructed sources (i.e., collection of 
fugitive emissions components located at well sites and compressor 
stations), the EPA is proposing an alternative fugitive emissions 
monitoring and repair program that includes bimonthly screening for 
large emission events using advanced measurement technologies followed 
with at least annual OGI in accordance with the proposed 40 CFR part 
60, appendix K (``appendix K''), which is included in this action and 
outlines the proposed procedures that must be followed to identify 
emissions using OGI.\199\ Additionally, we are proposing this same 
alternative screening using advanced measurement technologies as an 
alternative presumptive standard for existing sources.
---------------------------------------------------------------------------

    \199\ ``Determination of Volatile Organic Compound and 
Greenhouse Gas Leaks Using Optical Gas Imaging'' located at Docket 
ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------

    Specifically, the EPA is proposing to allow owners and operators 
the option to comply with this alternative fugitive emissions standard 
instead of the proposed ground based OGI surveys summarized in sections 
XI.A.2 and XI.A.3. The EPA proposes to require owners and operators 
choosing this alternative standard to do so for all affected well sites 
and compressor stations within a company-defined area. This company-
defined area could be a county, sub-basin, or other appropriate 
geographic area. Under this proposed alternative, the EPA proposes to 
require a screening survey on a bimonthly basis using a methane 
detection technology that has been demonstrated to achieve a minimum 
detection threshold of 10 kg/hr. This screening survey would be used to 
identify individual sites (i.e., well sites and compressor stations) 
where a follow-up ground-based OGI survey of all fugitive emissions 
components at the site is needed because fugitive emissions have been 
detected. Given the proposed minimum detection threshold of 10 kg/hr, 
which would constitute a significant emissions event, the EPA believes 
this follow-up OGI survey should be completed in an expeditious 
timeframe, therefore we are proposing to require this follow-up OGI 
survey of all fugitive emissions components at the site within 14 days 
of the screening survey. However, additional information is needed to 
fully evaluate the appropriateness of this deadline. Therefore, the EPA 
is soliciting comment on the proposed 14-day deadline for a follow-up 
OGI survey and information that would allow further evaluation of other 
potential deadlines to require.
    Next, for sites with emissions identified during screening and 
subject to this follow-up OGI survey, the EPA proposes that any 
fugitive emissions identified must be repaired, including those 
emissions identified during the screening survey. For purposes of this 
proposal, the EPA is proposing the same repair deadlines as those for 
the ground based OGI requirements discussed in sections XI.A.2 and 
XI.A.3, which are a first attempt at repair within 30 days of the OGI 
survey and final repair completed within 30 days of the first attempt. 
As noted in section XI.A.1, some equipment types with large emissions 
warrant a requirement for root cause analysis rather than simply 
repairing the emission source. The EPA solicits comment on how that 
root cause analysis with corrective action approach could be applied in 
this proposed alternative screening approach. Further, because large 
emission events, especially those identified during the screening 
surveys, contribute disproportionately to emissions, the EPA is also 
soliciting comment on how to structure a requirement that would tier 
repair deadlines based on the severity of the fugitive emissions when 
using this proposed alternative standard. See section XI.A.2 for 
additional discussion of this solicitation on tiered repairs.
    In addition to the bimonthly screening surveys proposed above, the 
EPA recognizes that component-level fugitive emissions may still be 
present at sites where the screening survey does not detect emissions. 
Therefore, in conjunction with these bimonthly screenings performed 
with the advanced measurement technology, the EPA is proposing to 
require a full OGI (or EPA Method 21) survey at least annually at each 
individual site utilizing the alternative screening standard. If the 
owner or operator performs an OGI survey in response to emissions found 
during the bimonthly screening survey, that OGI survey would count as 
the annual OGI survey; a second survey would not be required to comply 
with the annual OGI survey requirement and the clock would restart with 
the next annual survey due within 12 calendar months. The overall 
purpose of this annual OGI survey is to ensure that each individual 
site is surveyed with OGI at least annually, even where large emissions 
are not detected during the screening surveys using advanced 
measurement technology. The EPA is not allowing EPA Method 21 for use 
during the proposed follow-up OGI surveys when screening detects 
emissions because EPA Method 21 is not appropriate for detecting the 
sources of large emission events, such as malfunctioning control 
devices.
    Finally, the EPA is proposing to require that owners and operators 
include information specific to the alternative standard within their 
fugitive emissions monitoring plan. Since the 2016 NSPS OOOOa, owners 
and operators have been required to develop and maintain a fugitive 
emissions monitoring plan for all sites subject to the fugitive 
emissions requirements. This monitoring plan includes information 
regarding which sites are covered under the plan, which technology is 
being used (e.g., OGI or EPA Method 21), and site or company-

[[Page 63176]]

specific procedures that are employed to ensure compliant surveys. The 
EPA is proposing to add a requirement that the monitoring plan also 
address sites that are utilizing the proposed alternative standard. 
Specifically, the EPA is proposing a requirement to include the 
following information when the alternative standard is applied:
     Identification of the sites opting to comply with the 
alternative screening approach;
     General description of each site to be monitored, 
including latitude and longitude coordinates of the asset in decimal 
degrees to an accuracy and precision of five decimals of a degree using 
the North American Datum of 1983;
     Description of the measurement technology;
     Verification that the technology meets the 10 kg/hr 
methane detection threshold, including supporting data to demonstrate 
the sensitivity of the measurement technology as applied;
     Procedures for a daily verification check of the 
measurement sensitivity under field conditions (e.g., controlled 
releases);
     Standard operating procedures consistent with EPA's 
guidance \200\ and to include safety considerations, measurement 
limitations, personnel qualification/responsibilities, equipment and 
supplies, data and record management, and quality assurance/quality 
control (i.e., initial and ongoing calibration procedures, data quality 
indicators, and data quality objectives); and
---------------------------------------------------------------------------

    \200\ Guidance for Preparing Standard Operating Procedures 
(SOPs), EPA/600/B-07/001, April 2007, https://www.epa.gov/sites/default/files/2015-06/documents/g6-final.pdf.
---------------------------------------------------------------------------

     Procedures for conducting the screening.
    In the event that an owner or operator uses multiple technologies 
covered by one monitoring plan, the owner or operator would identify 
which technology is to be used on which site within the monitoring 
plan.
    In addition to the proposed requirements within the monitoring 
plan, the EPA is also proposing specific recordkeeping and reporting 
requirements associated with the follow-up OGI surveys that are 
consistent with the recordkeeping and reporting required for OGI 
surveys in NSPS OOOOa as amended in the 2020 Technical Rule. See 
section X.B.1.h and X.B.1.i. The EPA is soliciting comment on when 
notifications would be required for sites where the alternative 
standard is applied. Further, the EPA is soliciting comment on whether 
submission of the monitoring plan, and/or Agency approval before 
utilizing the alternative standard is necessary to ensure consistency 
in screening survey procedures in the absence of finalized methods or 
procedures.
    While the EPA is proposing the above alternative screening 
requirements, additional information is necessary to further refine the 
specific alternative work practice as it relates to the available 
technologies. Specific information is requested in the following 
paragraphs, and, if received, would allow the EPA to better analyze the 
BSER for fugitive emissions at well sites and compressor stations 
through a supplemental proposal.
    First, the EPA solicits comment on the use of 10 kg/hr as the 
minimum detection threshold for the advanced measurement technologies 
used in the alternative screening approach, including data that would 
support consideration of another detection threshold. The EPA also 
solicits comment on whether a matrix approach should be developed, 
instead of prescribing one detection threshold and screening frequency, 
and what that matrix should look like. In the matrix approach, the 
frequency of the screening surveys and regular OGI (or EPA Method 21) 
surveys would be based on the sensitivity of the technology, with the 
most sensitive detection thresholds having the least frequent screening 
and survey requirements and the least sensitive detection thresholds 
having the most frequent screening and survey requirements. For 
example, sites that are screened using a technology with a detection 
threshold of 1 kg/hr may require less frequent screening and may 
require an OGI survey less frequently than sites screened using a 
technology with a detection threshold of 50 kg/hr. We are also 
soliciting comment on the detection sensitivity of commercially 
available methane detection technologies based on conditions expected 
in the field, as well as factors that affect the detection sensitivity 
and how the detection sensitivity would change with these factors.
    Next, the EPA is soliciting comment on the standard operating 
procedures being used for commercially available technologies, 
including any manufacturer recommended data quality indicators and data 
quality objectives in use to validate these measurements. Additionally, 
for those commercially available technologies that quantify methane 
emissions rather than just detect methane, we are soliciting comment on 
the range of quantification based on conditions one would expect in the 
field.
    The EPA is seeking information that would allow us to further 
evaluate the potential costs and assumed emission reductions achieved 
through an alternative screening program. Therefore, the EPA is seeking 
information on the cost of screening surveys using different types of 
advanced measurement technologies, singularly or in combination, and 
factors that affect that cost (e.g., is it influenced by the number of 
sites and length of survey). Additionally, we are interested in 
understanding whether there would be opportunities for cost-sharing 
among operators and whether any aspect of regulation would be 
beneficial or required to facilitate such cost-sharing opportunities. 
We also solicit comment on whether these technologies and cost-sharing 
opportunities would allow for cost-effective monitoring at all sites 
owned or operated by the same company within a sub-basin or other 
discrete geographic area. Further, we seek comment on the current and 
expected availability of these advanced measurement technologies and 
the supporting personnel and infrastructure required to deploy them, 
how their cost and availability might be affected if demand for these 
technologies were to increase, and how quickly the use of these 
technologies could expand if they were integrated into this regulatory 
program either as a required element of fugitive monitoring or as this 
proposed alternative work practice.
    The EPA recognizes that the approach outlined above may not be 
suited to continuous monitoring technologies, such as network sensors 
or open-path technology. While these systems typically have the ability 
to meet the 10 kg/hr methane threshold discussed above \201\ the 
emissions from these well sites can be intermittent or tied to process 
events (e.g., pigging operations). We are concerned that the proposed 
alternative screening approach would trigger an OGI survey for every 
emission event, regardless of type, duration, or size, if a continuous 
monitoring technology is installed. This would disincentivize the use 
of continuous monitoring systems, which could be valuable tools in 
finding large emission sources sooner. While we believe that a 
framework for advanced measurement technologies that monitor sites 
continuously should be developed, we do not currently have all of the 
information that is necessary to develop

[[Page 63177]]

an equivalence demonstration for these monitors or to ensure the 
technology works appropriately over time. Therefore, we are soliciting 
comment on how an equivalence demonstration can be made for these 
continuous monitoring technologies.
---------------------------------------------------------------------------

    \201\ Alden et al., Single-Blind Quantification of Natural Gas 
Leaks from 1 km Distance Using Frequency Combs, Environmental 
Science and Technology, 2019, 53, 2908-2917.
---------------------------------------------------------------------------

    The framework for a continuous monitoring technology would need to 
cover the following items at a minimum: The number of monitors needed 
and the placement of the monitors; minimum response factor to methane; 
minimum detection level; frequency of data readings; how to interpret 
the monitor data to determine what emissions are a detection versus 
baseline emissions; how to determine allowable emissions versus leaks; 
the meteorological data criteria; measurement systems data quality 
indicators; calibration requirements and frequency of calibration 
checks; how downtime should be handled; and how to handle situations 
where the source of emissions cannot be identified even when the 
monitor registers a leak. We are soliciting comment on how to develop a 
framework that is flexible for multiple technologies while still 
ensuring that emissions are adequately detected and the monitors 
respond appropriately over time. Additionally, we are soliciting 
comment on whether these continuous monitors need to respond to other 
compounds as well as methane; how close a meteorological station must 
be to the monitored site; and whether OGI or EPA Method 21 surveys 
should still be required, and if so, at what frequency.
    At this time, the EPA does not have enough information to determine 
how this proposed alternative standard using advanced measurement 
technologies compares to the proposed BSER of OGI monitoring at well 
sites at a frequency that is based on the site baseline methane 
emissions as described in section XI.A.3.a, or to quarterly OGI 
monitoring at compressor stations. Information provided through this 
solicitation may be used to reevaluate BSER through a supplemental 
proposal.
6. Use of Information From Communities and Others
    As the EPA learned during the Methane Detection Technology 
Workshop, industry, researchers, and NGOs have utilized advanced 
methane detection systems to quickly identify large emission sources 
and target ground based OGI surveys. State and local governments, 
industry, researchers, and NGOs have been utilizing advanced 
technologies to better understand the detection of, source of, and 
factors that lead to large emission events. The EPA anticipates that 
the use of these techniques by a variety of parties, including 
communities located near oil and gas facilities or affected by oil and 
gas pollution, will continue to grow as these technologies become more 
widely available and decline in cost.
    The EPA is seeking comment on how to take advantage of the 
opportunities presented by the increasing use of these technologies to 
help identify and remediate large emission events (commonly known as 
``super-emitters''). Specifically, the EPA seeks comment on how to 
evaluate, design, and implement a program whereby communities and 
others could identify large emission events and, where there is 
credible information of such a large emission event, provide that 
information to owners and operators for subsequent investigation and 
remediation of the event. The EPA understands that these large emission 
events are often attributable to malfunctions or abnormal process 
conditions that should not be occurring at a well-operating, well-
maintained, and well-controlled facility that has implemented the 
various BSER measures identified in this proposal.
    We generally envision a program for finding large emission events 
that consists of a requirement that, if emissions are detected above a 
defined threshold by a community, a Federal or State agency, or any 
other third party, the owner or operator would be required to 
investigate the event, do a root cause analysis, and take appropriate 
action to mitigate the emissions, and maintain records and report on 
such events.
    We seek comment on all aspects of this concept, which would be 
developed further as part of a supplemental proposal. Among other 
things, the EPA is soliciting comment on an emissions threshold that 
could be used to define these large emission events, and which types of 
technologies would be suitable for identification of large emissions 
events. For example, there are some satellite systems capable of 
generally identifying emissions above 100 kg/hr with a spatial 
resolution which could allow identification of emission events from an 
individual site.\202\ Additionally there are other satellites systems 
available which have wider spatial resolution that can identify large 
methane emission events, and when combined with finer resolution 
platforms, could allow identification of emission events from an 
individual site. The EPA believes that any emissions visible by 
satellites should qualify as large emission events. However, the EPA 
solicits comment on whether the threshold for a large emission should 
be lower than what is visible by satellite.
---------------------------------------------------------------------------

    \202\ D.J. Varon, J. McKeever, D. Jervis, J.D. Maasakkers, S. 
Pandey, S. Houweling, I. Aben, T. Scarpelli, D.J. Jacob, Satellite 
Discovery of anomalously Large Methane Point Sources from Oil/Gas 
Production, available at https://doi.org/10.1029/2019GL083798, 
October 25, 2019.
---------------------------------------------------------------------------

    Second, in order to make this approach viable, the EPA would need 
to specify what actions an owner or operator must take when notified of 
a large emission event, including deadlines for taking such actions. 
These elements could include the specific steps the company would take 
to investigate the notification and mitigate the event, such as 
verifying the location of the emissions, conducting ground 
investigations to identify the specific emission source, conducting a 
root cause analysis, performing corrective action within a specific 
timeframe to mitigate the emissions, and preventing ongoing and future 
chronic or intermittent large emissions from that source. These steps 
could be incorporated into a fugitive emissions monitoring plan 
maintained by the owner or operator, and failure to take the actions 
specified by the owner or operator in the plan could be considered 
noncompliance. We seek comment on what specific follow-up actions or 
other procedures would be appropriate to require once a large emission 
event is identified, as well as appropriate deadlines for these 
actions.
    Third, the EPA would need to define guidelines for credible and 
actionable data. The EPA is soliciting comment on what these guidelines 
should entail and whether specific protocols (e.g., permissible 
detection technologies, data analytics, operator training, data 
reporting, public access, and data preservation) should govern the 
collection of such data and whether such data should conform to any 
type of certification. If specific certification or protocols are 
necessary, the EPA is soliciting comment on how that certification 
should be obtained.
    Fourth, we are also soliciting comment on best practices for the 
identification of the correct owner or operator of a facility 
responsible for such large emissions, since such information is 
necessary to halt such large-volume emission events, and how the 
community or other third-party should notify the owner or operator, as 
well as how the delegated authority should be made aware of such 
notification.
    Finally, we are soliciting comment on whether the EPA should 
develop a model plan for responding to notifications that companies 
could adopt instead of developing company- or site-specific plans, 
including what

[[Page 63178]]

elements should be included in that model plan.

B. Storage Vessels

1. NSPS OOOOb
    The current NSPS in subpart OOOOa for storage vessels is to reduce 
VOC emissions by 95 percent, and the standard applies to a single 
storage vessel with a potential for 6 or more tpy of VOC emissions. 
Based on our analysis, which is summarized in section XII.B.1, the EPA 
is proposing to retain the 95 percent reduction standard as it 
continues to reflect the BSER for reducing VOC emissions from new 
storage vessels. The EPA is also proposing to set GHG standards (in the 
form of limitations on methane emissions) for storage vessels in this 
action. Because the BSER for reducing VOC and methane emissions are the 
same, the proposed GHG standard is to reduce methane emissions by 95 
percent. The EPA continues to support the capture of gas vapors from 
storage vessels rather than the combustion of what can be an energy-
rich saleable product. We incentivize this by recognizing the use of 
vapor recovery as a part of the process, therefore the storage vessel 
emissions would not contribute to the site's potential-to-emit.
    Under the current NSPS for storage vessels, an affected facility is 
a single storage vessel with potential VOC emissions of 6 tpy or 
greater. The EPA is proposing to include a tank battery as a storage 
vessel affected facility. The EPA proposes to define a tank battery as 
a group of storage vessels that are physically adjacent and that 
receive fluids from the same source (e.g., well, process unit, 
compressor station, or set of wells, process units, or compressor 
stations) or which are manifolded together for liquid or vapor 
transfer.
    To determine whether a single storage vessel is an affected 
facility, the owner or operator would compare the 6 tpy VOC threshold 
to the potential emissions from that individual storage vessel; to 
determine whether a tank battery is an affected facility, the owner or 
operator would compare the 6 tpy VOC threshold to the aggregate 
potential emissions from the group of storage vessels. For new, 
modified, or reconstructed sources, if the potential VOC emissions from 
a storage vessel or tank battery exceeds the 6 tpy threshold, then it 
is a storage vessel affected facility and controls would be required. 
This is consistent with the EPA's initial determination in the 2012 
NSPS OOOO that controlling VOC emissions as low as 6 tpy from storage 
vessels is cost-effective. The proposed standard of 95 percent 
reduction of methane and VOC emissions, which is the same as the 
current VOC standard in the 2012 NSPS OOOO and 2016 NSPS OOOOa, can be 
achieved by capturing and routing the emissions utilizing a cover and 
closed vent system that routes captured emissions to a control device 
that achieves an emission reduction of 95 percent, or that routes 
captured emissions to a process.
    Finally, we are proposing specific provisions to clarify what 
circumstances constitute a modification of an existing storage vessel 
affected facility (single storage vessel or tank battery), and thus 
subject it to the proposed NSPS instead of the EG. The EPA is proposing 
that a single storage vessel or tank battery is modified when physical 
or operational changes are made to the single storage vessel or tank 
battery that result in an increase in the potential methane or VOC 
emissions. Physical or operational changes would be defined to include: 
(1) The addition of a storage vessel to an existing tank battery; (2) 
replacement of a storage vessel such that the cumulative storage 
capacity of the existing tank battery increases; and/or (3) an existing 
tank battery or single storage vessel that receives additional crude 
oil, condensate, intermediate hydrocarbons, or produced water 
throughput (from actions such as refracturing a well or adding a new 
well that sends these liquids to the tank battery). The EPA is 
proposing to require that the owner or operator recalculate the 
potential VOC emissions when any of these actions occur on an existing 
tank battery to determine if a modification has occurred. The existing 
tank battery will only become subject to the proposed NSPS if it is 
modified pursuant to this definition of modification and its potential 
VOC emissions exceed the proposed 6 tpy VOC emissions threshold.
2. EG OOOOc
    Based on our analysis, which is summarized in section XII.B.2, the 
EPA is proposing EG for existing storage vessels which include a 
presumptive GHG standard (in the form of limitation on methane 
emissions). For existing sources under the EG, the EPA is proposing to 
define a designated facility as an existing tank battery with potential 
methane emissions of 20 tpy or greater. The proposed definition of a 
tank battery in the EG is the same as the definition proposed for new 
sources; however, since the designated pollutant in the context of the 
EG is methane, determination of whether a tank battery is a designated 
facility would be based on its potential methane emissions only. Our 
analysis shows that it is cost effective to control an existing tank 
battery with potential methane emissions 20 tpy or higher. Similar to 
the proposed NSPS, we are proposing a presumptive standard that 
includes a 95 percent reduction of the methane emissions from each 
existing tank battery that qualifies as a designated facility. Such a 
standard could be achieved by capturing and routing the emissions by 
utilizing a cover and closed vent system that routes captured emissions 
to a control device that achieves an emission reduction of 95 percent, 
or routes emission back to a process.

C. Pneumatic Controllers

1. NSPS OOOOb
    The current NSPS OOOOa regulates certain continuous bleed natural 
gas driven pneumatic controllers, but includes different standards 
based on whether the pneumatic controller is located at an onshore 
natural gas processing plant. If the pneumatic controller is located at 
an onshore natural gas processing plant, then the current NSPS requires 
a zero bleed rate. If the pneumatic controller is located elsewhere, 
then the current NSPS requires the pneumatic controller to operate at a 
natural gas bleed rate no greater than 6 scfh. The current NSPS does 
not regulate intermittent vent natural gas driven pneumatic controllers 
at any location.
    Based on our analysis, which is summarized in section XII.C.1, the 
EPA is proposing pneumatic controller standards for NSPS OOOOb as 
follows. First, in addition to each single natural gas-driven 
continuous bleed pneumatic controller being an affected facility, the 
EPA proposes to define each natural gas-driven intermittent vent 
pneumatic controller as an affected facility. The EPA believes these 
pneumatic controllers should be covered by NSPS OOOOb because natural 
gas-driven intermittent devices represent a large majority of the 
overall population of pneumatic controllers and are responsible for the 
majority of emissions from these sources. We are proposing to define an 
intermittent vent natural gas-driven pneumatic controller as a 
pneumatic controller that is not designed to have a continuous bleed 
rate but is instead designed to only release natural gas to the 
atmosphere as part of the actuation cycle. This affected facility 
definition would apply at all sites, including natural gas processing 
plants.
    Second, we are proposing a requirement that all controllers

[[Page 63179]]

(continuous bleed and intermittent vent) must have a VOC and methane 
emission rate of zero. The proposed rule does not specify how this 
emission rate of zero must be achieved, but a variety of viable options 
are discussed in Section XII.C. including the use of pneumatic 
controllers that are not driven by natural gas such as air-driven 
pneumatic controllers and electric controllers, as well as natural gas 
driven controllers that are designed so that there are no emissions, 
such as self-contained pneumatic controllers. As noted above, the EPA 
is proposing that the definition of an affected facility would be each 
pneumatic controller that is driven by natural gas and that emits to 
the atmosphere. As such, pneumatic controllers that are not driven by 
natural gas would not be affected facilities, and thus would not be 
subject to the pneumatic controller requirements of NSPS OOOOb. 
Similarly, controllers that are driven by natural gas but that do not 
emit to the atmosphere would also not be affected facilities. In order 
to demonstrate that a particular pneumatic controller is not an 
affected facility, owners and operators should maintain documentation 
to show that such controllers are not natural gas driven such as 
documentation of the design of the system, and to ensure that they are 
operated in accordance with the design so that there are no emissions.
    In both NSPS OOOO and OOOOa, there is an exemption from the 
standards in cases where the use of a pneumatic controller affected 
facility with a bleed rate greater than the applicable standard is 
required based on functional needs, including but not limited to 
response time, safety, and positive actuation. The EPA is not 
maintaining this exemption in the proposed NSPS OOOOb, except for in 
very limited circumstances explained in section XII.C. As discussed in 
section XII.C., the reasons to allow for an exemption based on 
functional need in NSPS OOOO and OOOOa were based on the inability of a 
low-bleed controller to meet the functional requirements of an owner/
operator such that a high-bleed controller would be required in certain 
instances. Since we are now proposing that pneumatic controllers have a 
methane and VOC emission rate of zero, we do not believe that the 
reasons related to the use of low bleed controllers are still 
applicable. However, EPA is soliciting comment on whether owners/
operators believe that maintaining such an exemption based on 
functional need is appropriate, and if so why.
    The proposed rule includes an exemption from the zero-emission 
requirement for pneumatic controllers in Alaska at locations where 
power is not available. In these situations, the proposed standards 
require the use of a low-bleed controller instead of high-bleed 
controller. Further, in these situations (controllers in Alaska at 
location without power) the proposed rule includes the exemption that 
would allow the use of high-bleed controllers instead of low-bleed 
based on functional needs. Lastly, in these situations owners/operators 
must inspect intermittent vent controllers to ensure they are not 
venting during idle periods.
2. EG OOOOc
    In this action, the EPA is proposing to define designated 
facilities (existing sources) analogous to the affected facility 
definitions described above for pneumatic controllers under the NSPS. 
For the reasons discussed in section XII.C.2, the BSER analysis for 
existing sources supports proposing presumptive standards for reducing 
methane emissions from existing pneumatic controllers that are the same 
as those the EPA is proposing for new, modified, or reconstructed 
sources (for NSPS OOOOb).

D. Well Liquids Unloading Operations

    Well liquids unloading operations, which are currently unregulated 
under the NSPS OOOOa, refer to unloading of liquids that have 
accumulated over time in gas wells and are impeding or halting 
production. The EPA is proposing standards in the NSPS OOOOb to reduce 
methane and VOC emissions during liquids unloading operations.
1. NSPS OOOOb
    We are proposing standards to reduce VOC and methane emissions from 
each well that conducts a liquids unloading operation. Based on our 
analysis, which is summarized in section XII.D.1, we are proposing a 
standard under NSPS OOOOb that requires owners or operators to perform 
liquids unloading with zero methane or VOC emissions. In the event that 
it is technically infeasible or not safe to perform liquids unloading 
with zero emissions, the EPA is proposing to require that an owner or 
operator establish and follow BMPs to minimize methane and VOC 
emissions during liquids unloading events to the extent possible.
    The EPA is co-proposing two regulatory approach options to 
implement the rule requirements.
    For Option 1, the affected facility would be defined as every well 
that undergoes liquids unloading. This would mean that wells that 
utilize a non-emitting method for liquids unloading would be affected 
facilities and subject to certain reporting and recordkeeping 
requirements. These requirements would include records of the number of 
unloadings that occur and the method used. A summary of this 
information would also be required to be reported in the annual report. 
The EPA also recognizes that under some circumstances venting could 
occur when a selected liquids unloading method that is designed to not 
vent to the atmosphere is not properly applied (e.g., a technology 
malfunction or operator error). Under the proposed rule Option 1 owners 
and operators in this situation would be required to record and report 
these instances, as well as document and report the length of venting, 
and what actions were taken to minimize venting to the maximum extent 
possible.
    For wells that utilize methods that vent to the atmosphere, the 
proposed rule would require that owners or operators (1) Document why 
it is infeasible to utilize a non-emitting method due to technical, 
safety, or economic reasons; (2) develop BMPs that ensure that 
emissions during liquids unloading are minimized including, at a 
minimum, having a person on-site during the liquids unloading event to 
expeditiously end the venting when the liquids have been removed; (3) 
follow the BMPs during each liquids unloading event and maintain 
records demonstrating they were followed; and (4) report the number of 
liquids unloading events in an annual report, as well as the unloading 
events when the BMP was not followed. While the proposed rule would not 
dictate all of the specific practices that must be included, it would 
specify minimum acceptance criteria required for the types and nature 
of the practices. Examples of the types and nature of the required 
practice elements are provided in XII.D.1.e.
    For Option 2, the affected facility would be defined as every well 
that undergoes liquids unloading using a method that is not designed to 
totally eliminate venting. The significant difference in this option is 
that wells that utilize non-venting methods would not be affected 
facilities that are subject to the NSPS OOOOb. Therefore, they would 
not have requirements other than to maintain records to document that 
they used non-venting liquids unloading methods. The requirements for 
wells that use methods that vent would be the same as described above 
under Option 1. The EPA solicits comment on including information such 
as where the well stream was directed during unloading and emissions

[[Page 63180]]

manifested and whether an estimate of the VOC and methane emissions 
generated should be included in the annual report.
    There are several techniques owners and operators can choose from 
to unload liquids, including manual unloading, velocity tubing or 
velocity strings, beam or rod pumps, electric submergence pumps, 
intermittent unloading, gas lift (e.g., use of a plunger lift), foam 
agents, wellhead compression, and routing the gas to a sales line or 
back to a process. Although the unloading method employed by an owner 
or operator can itself be a method that can be employed in such a way 
that mitigates/eliminates venting of emissions from a liquids unloading 
event, indicating a particular method to meet a particular well's 
unloading needs is a production engineering decision. Based on 
available information, liquids unloading operations are often conducted 
in such a way that eliminates venting to the atmosphere and there are 
many options that include techniques and procedures that an owner or 
operator can choose from to achieve this standard (discussed in section 
XII.D.e of this preamble).
    However, the EPA recognizes that there may be reasons that a non-
venting method is infeasible for a particular well, and the proposed 
rule would allow for the use of BMPs to reduce the emissions to the 
maximum extent possible for such cases (discussed in section XII.D of 
this preamble). BMPs include, but are not limited to, following 
specific steps that create a differential pressure to minimize the need 
to vent a well to unload liquids and reducing wellbore pressure as much 
as possible prior to opening to atmosphere via storage tank, unloading 
through the separator where feasible, and requiring an operator to 
remain on-site throughout the unloading, and closure of all well head 
vents to the atmosphere and return of the well to production as soon as 
practicable. For example, where a plunger lift is used, the plunger 
lift can be operated so that the plunger returns to the top and the 
liquids and gas flow to the separator. Under this scenario, venting of 
the gas can be minimized and the gas that flows through the separator 
can be routed to sales. In situations where production engineers select 
an unloading technique that vents emissions or has the potential to 
vent emissions to the atmosphere, owners and operators already often 
implement BMPs in order to increase gas sales and reduce emissions and 
waste during these (often manual) liquids unloading activities.
2. EG OOOOc
    The EPA has determined that each well liquids unloading event 
represents a modification, which will make the well subject to new 
source standards under the NSPS for purposes of the liquids unloading 
standards.\203\ Therefore, after the effective date of NSPS OOOOb, the 
first time a well undergoes liquids unloading it will become subject to 
NSPS OOOOb. This will mean that there will never be a well that 
undergoes liquids unloading that will be existing. Therefore, we are 
not proposing presumptive standards under the subpart OOOOc EG.
---------------------------------------------------------------------------

    \203\ To clarify further, when a well liquids unloading event 
represents a modification, this does not make the whole well site a 
new source. Rather, the modification will make the well subject to 
NSPS for only the liquids unloading standards.
---------------------------------------------------------------------------

E. Reciprocating Compressors

1. NSPS OOOOb
    The current NSPS in subpart OOOOa for reducing VOC and methane 
emissions from reciprocating compressors is to replace the rod packing 
on or before 26,000 hours of operation or 36 calendar months, or to 
route emissions from the rod packing to a process through a closed vent 
system under negative pressure. The affected facility is each 
reciprocating compressor, with the exception of reciprocating 
compressors located at well sites. Based on the analysis in section 
XII.E.1, the proposed BSER for reducing GHGs and VOC from new 
reciprocating compressors is replacement of the rod packing based on an 
annual monitoring threshold. Under this proposal for the NSPS, we would 
continue to retain, as an alternative, the option of routing rod 
packing emissions to a process via a closed vent system under negative 
pressure. In this proposed updated standard, the owner or operator of a 
reciprocating compressor affected facility would be required to monitor 
the rod packing emissions annually using a flow measurement. When the 
measured leak rate exceeds 2 scfm (in pressurized mode), replacement of 
the rod packing would be required.
    As mentioned above, reciprocating compressors that are located at 
well sites are not affected facilities under the 2016 NSPS OOOOa. The 
EPA previously excluded them because we found the cost of control to be 
unreasonable. 81 FR 35878 (June 3, 2016). Our current analysis, as 
summarized in section XII.E.1, continues to support this exclusion for 
a subset of well sites so this proposal for NSPS OOOOb includes that 
same exclusion for well sites that are not centralized production 
facilities. See section XI.L for additional details on centralized 
production facilities. As described in that section, the EPA is 
proposing to apply the proposed standards to reciprocating compressors 
located at centralized production facilities.
2. EG OOOOc
    Based on the analysis in section XII.E.2, the EPA is proposing EG 
that include a presumptive GHG standard (in the form of limitation on 
methane emissions) for existing reciprocating compressors that is the 
same as the proposed NSPS, including applying these presumptive 
standards to reciprocating compressors located at existing centralized 
tank batteries.

F. Centrifugal Compressors

1. NSPS OOOOb
    The current NSPS in subpart OOOOa for wet seal centrifugal 
compressors is 95 percent reduction of GHGs and VOC emissions. The 
affected facility is each wet seal centrifugal compressor, with the 
exception of wet seal centrifugal compressors located at well sites. 
Based on the analysis in section XII.F.1, the BSER for reducing GHGs 
and VOC from new, reconstructed, or modified wet seal centrifugal 
compressors is the same as the current standard, which is 95 percent 
reduction of GHG and VOC emissions. The standard can be achieved by 
capturing and routing the emissions, using a cover and closed vent 
system, to a control device that achieves an emission reduction of 95 
percent, or by routing captured emissions to a process.
    As discussed above, wet seal centrifugal compressors that are 
located at well sites are not affected facilities under the 2016 NSPS 
OOOOa. The EPA previously excluded them because data available at the 
time did not suggest there were a large number of wet seal centrifugal 
compressors located at well sites. 81 FR 35878 (June 3, 2016). Our 
analysis continues to support this exemption for wet seal centrifugal 
compressors located at well sites that are not centralized production 
facilities. See section XI.L for additional details on centralized 
production facilities. As described in that section, the EPA is 
proposing to apply the proposed standards to centrifugal compressors 
located at centralized production facilities.
2. EG OOOOc
    Based on the analysis in section XII.F.2, the EPA is proposing EG 
that

[[Page 63181]]

include a presumptive GHG standard (in the form of limitation on 
methane emissions) for existing wet seal centrifugal compressors that 
is the same as the NSPS, including applying these presumptive standards 
to wet seal centrifugal compressors at existing centralized tank 
batteries.

G. Pneumatic Pumps

1. NSPS OOOOb
    The current NSPS in subpart OOOOa regulates individual natural gas 
driven diaphragm pneumatic pumps at well sites and at onshore natural 
gas processing plants. The current NSPS for a natural gas driven 
diaphragm pneumatic pump at well sites requires 95 percent control of 
GHGs and VOCs if there is an existing control device or process on site 
where emissions can be routed. There are two exceptions to the 95 
percent control requirement: (1) The existing control or process 
achieves less than 95 percent reduction; or (2) it is technically 
infeasible to route to the existing control device or process. In 
addition, the current NSPS in OOOOa specifies that boilers and process 
heaters are not considered control devices and that routing emissions 
from pneumatic pump discharges to boilers and process heaters is not 
considered routing to a process. For more discussion on the use of 
boilers and process heaters as control devices for pneumatic pump 
emissions, see section X.B.2 of this preamble. The current NSPS for a 
natural gas driven diaphragm pneumatic pump at an onshore natural gas 
processing plant is a natural gas emission rate of zero, based on 
natural gas as a surrogate for VOC and GHG, the two regulated 
pollutants.
    For NSPS OOOOb, we are proposing to expand the applicability of the 
standard currently in NSPS OOOOa in two ways. The first is by including 
all natural gas driven diaphragm pumps as affected facilities in the 
transmission and storage segment in addition to the production and 
natural gas processing segments. The second is that we are expanding 
the affected facility definition to include natural gas driven piston 
pumps in addition to diaphragm pumps. The proposed definition of an 
affected facility would continue to exclude lean glycol circulation 
pumps that rely on energy exchange with the rich glycol from the 
contractor.
    Based on our analysis, which is summarized in section XII.G.1, we 
are proposing to retain the current standard for a natural gas driven 
diaphragm pneumatic pump at well sites because the BSER for reducing 
VOC and methane emissions from such pumps at a well site continues to 
be routing to a combustion device or process, but only if the control 
device or process is already available on site. As before, the current 
analysis continues to show that it is not cost-effective to require the 
owner or operator of a pneumatic pump to install a new control device 
or process onsite to capture emissions solely for this purpose. 
Moreover, even where a control device or process is available onsite 
that would achieve at least 95 percent control, the EPA is aware that 
it may not be technically feasible in some instances to route the 
pneumatic pump to the control device or process. In this situation, the 
proposed rule would exempt the owner and operator from this requirement 
provided that they document the technical infeasibility and submit it 
in an annual report. Another circumstance is that it may be feasible to 
route the emissions to a control device, but the control cannot achieve 
95 percent control. In this instance, the proposed rule would exempt 
the owner or operator from the 95 percent requirement, provided that 
the owner or operator maintain records demonstrating the percentage 
reduction that the control device is designed to achieve. In this way, 
the standard would achieve emission reductions with regard to pneumatic 
pump affected facilities even if the only available control device 
cannot achieve a 95 percent reduction. For more discussion of the 
technical infeasibility aspects of the pneumatic pump requirements, see 
section X.B.2 of this preamble. We are proposing to expand these 
requirements to all diaphragm pumps at all sites in the production 
segment, as well as at all transmission and storage sites. In addition, 
we are proposing that these requirements would also include emissions 
from piston pneumatic pumps at all sites in the production segment.
    We are not proposing any change to the current standard of zero 
natural gas emission for natural gas driven diaphragm pneumatic pumps 
located at onshore natural gas processing plants, other than the 
expansion of the affected facility definition to include piston pumps. 
Our analysis discussed in section XII.G.1 demonstrates this standard is 
the BSER.
2. EG OOOOc
    The EPA is proposing EG that include presumptive methane standards 
that are the same as described above for the NSPS OOOOb for existing 
natural gas driven diaphragm pneumatic pumps located at well sites and 
all other sites in the production segment (except processing plants) 
and transmission and storage segment where an existing control device 
exists. However, unlike the proposed methane standards in NSPS OOOOb 
for natural gas driven piston pneumatic pumps at sites in the 
production segment, the proposed presumptive standards under EG OOOOc 
exclude piston pumps from the 95 percent control requirements. The 
EPA's proposed emissions guidelines also include a presumptive methane 
standard for pneumatic pumps located at onshore natural gas processing 
plants that is the same as the proposed NSPS described above.

H. Equipment Leaks at Natural Gas Processing Plants

    Based on our analysis, which is summarized in section XII.H.1, the 
EPA is proposing to update the NSPS for reducing VOC and methane 
emissions from equipment leaks at onshore natural gas processing 
plants. Further, based on the same analysis in section XII.H.1 and the 
EPA's understanding that it is appropriate to apply that same analysis 
to existing sources, the EPA is also proposing EG that include these 
same LDAR requirements as presumptive standards for reducing methane 
leaks from existing equipment at onshore natural gas processing plants.
    The EPA is proposing to expand the definition of an affected 
facility (referred to as a ``equipment within a process unit'') and 
establish a new standard for reducing equipment leaks of VOC and 
methane emissions from new, modified, and reconstructed process units 
at onshore natural gas processing plants. This proposed standard would 
require (1) the use of OGI monitoring to detect equipment leaks from 
pumps, valves, and connectors, and (2) retain the current requirements 
in the 2016 NSPS OOOOa (which adopts by reference specific provisions 
of 40 CFR part 60, subpart VVa (``NSPS VVa'')) for PRDs, open-ended 
valves or lines, and closed vent systems and equipment designated with 
no detectable emissions.
    First, we are proposing to remove a threshold that excludes certain 
equipment within a process unit from being subject to the equipment 
leaks standards for onshore natural gas processing plants. While the 
current definition of an affected facility includes all equipment, 
except compressors, that is in contact with a process fluid containing 
methane or VOCs (i.e., each pump, PRD, open-ended valve or line, valve, 
and flange or other connector), the standards apply only to equipment 
``in VOC service,''

[[Page 63182]]

which ``means the piece of equipment contains or contacts a process 
fluid that is at least 10 percent VOC by weight.'' We are proposing to 
remove this VOC concentration threshold from the LDAR requirements for 
the following reasons. First, a VOC concentration threshold bears no 
relationship to the LDAR for methane and is therefore not an 
appropriate threshold for determining whether LDAR for methane applies. 
Second, since there would be no threshold for requiring LDAR for 
methane, any equipment not in VOC service would still be required to 
conduct LDAR for methane even if not for VOC, thus rendering this VOC 
concentration threshold irrelevant.
    Second, for all pumps, valves, and connectors located within an 
affected process unit at an onshore natural gas processing plant, we 
are proposing to require the use of OGI to identify leaks from this 
equipment on a bimonthly frequency (i.e., once every other month), 
which according to our analysis is the BSER for identifying and 
reducing leaks from this equipment. OGI monitoring would be conducted 
in accordance with the proposed appendix K,\204\ which is included in 
this action and outlines the proposed procedures that must be followed 
to identify leaks using OGI. As an alternative to bimonthly monitoring 
using OGI, we are proposing to allow affected facilities the option to 
comply with the requirements of NSPS VVa, which are the current 
requirements in the 2016 NSPS OOOOa.\205\ As explained in XII.A, our 
analysis shows that the proposed standards, which use OGI, achieve 
equivalent reduction of VOC and methane emissions as the current 
standards, which are based on EPA Method 21, but at a lower cost. While 
we no longer consider EPA Method 21 to be the BSER for reducing methane 
and VOC emissions from equipment leaks at onshore natural gas 
processing plants, we are retaining NSPS VVa as an alternative for 
owners and operators who prefer using EPA Method 21.
---------------------------------------------------------------------------

    \204\ ``Determination of Volatile Organic Compound and 
Greenhouse Gas Leaks Using Optical Gas Imaging'' located at Docket 
ID No. EPA-HQ-OAR-2021-0317.
    \205\ It is important to note that the stay of the connector 
monitoring requirements in 40 CFR 60.482-11a does not apply to 
connectors located at onshore natural gas processing plants. 
Therefore, where sources choose to comply with the requirements of 
NSPS VVa in place of the proposed OGI requirements, the standards in 
40 CFR 60.482-11a are applicable to all connectors in the process 
unit.
---------------------------------------------------------------------------

    Third, we are proposing to require a first attempt at repair for 
all leaks identified with OGI within 5 days of detection, and final 
repair completed within 15 days of detection. We are also proposing 
definitions for ``first attempt at repair'' and ``repaired.'' The 
proposed definitions would apply to the equipment leaks standards at 
natural gas processing plants as well as to fugitive emissions 
requirements at well sites and compressor stations. The proposed 
definition of ``first attempt at repair'' is an action taken for the 
purpose of stopping or reducing fugitive emissions or equipment leaks 
to the atmosphere. First attempts at repair include, but are not 
limited to, the following practices where practicable and appropriate: 
Tightening bonnet bolts; replacing bonnet bolts; tightening packing 
gland nuts; or injecting lubricant into lubricated packing. The 
proposed definition for ``repaired'' is fugitive emissions components 
or equipment are adjusted, replaced, or otherwise altered, in order to 
eliminate fugitive emissions or equipment leaks as defined in the 
subpart and resurveyed to verify that emissions from the fugitive 
emissions components or equipment are below the applicable leak 
definition. Repairs can include replacement with low-emissions (``low-
e'') valves or valve packing, where commercially available, as well as 
drill-and-tap with a low-e injectable. These low-e equipment meet the 
specifications of API 622 or 624. Generally, a low-e valve or valve 
packing product will include a manufacturer written warranty that it 
will not emit fugitive emissions at a concentration greater than 100 
ppm within the first five years. Further, we are proposing to 
incorporate the delay of repair provisions that are in 40 CFR 60.482-9a 
of NSPS VVa (and incorporated into NSPS OOOOa). These provisions would 
allow the delay of repairs where it is technically infeasible to 
complete repairs within 15 days without a process unit shutdown and 
require repair completion before the end of the next process unit 
shutdown.
    Fourth, we are proposing to retain the current requirements in NSPS 
OOOOa for open-ended valves or lines, closed vent systems and equipment 
designated with no detectable emissions, and PRDs. For open-ended 
valves or lines, we propose to retain the requirements in 40 CFR 
60.482-6a of NSPS VVa. Specifically, we are proposing that each open-
ended valve or line in a new or existing process unit must be equipped 
with a closure device (i.e., cap, blind flange, plug, or a second 
valve) that seals the open end at all times except during operations 
requiring process fluid flow through the open-ended valve or line. The 
EPA is soliciting comment on requiring OGI monitoring (or EPA Method 21 
monitoring for those opting for that alternative) on these open-ended 
valves or lines equipped with closure devices to ensure no emissions 
are going to the atmosphere. Specifically, the EPA is soliciting 
information that would aid in determining what additional costs would 
be incurred from either OGI or EPA Method 21 monitoring and repair of 
leaking open-ended valves or lines, and information on leak rates and 
concentrations of emissions, where monitoring has been performed.
    While the EPA is proposing to retain the no detectable emission 
requirement in NSPS OOOOa for closed vent systems and equipment 
designated as having no detectable emissions (e.g., valves or PRDs), 
the EPA is also soliciting comment on whether bimonthly OGI monitoring 
according to the proposed appendix K is appropriate to demonstrate 
compliance with this requirement. The current NSPS requires the closed 
vent systems \206\ and the other equipment described above to operate 
with no detectable emissions, as demonstrated by an instrument reading 
of less than 500 ppm above background with EPA Method 21. On December 
22, 2008, the EPA issued a final rule titled, ``Alternative Work 
Practice to Detect Leaks from Equipment'' (AWP).\207\ In that final 
rule, the EPA did not permit the use of OGI for this equipment, 
stating, ``the AWP is not appropriate for monitoring closed vent 
system, leakless equipment, or equipment designated as non-leaking. 
While the AWP will identify leaks with larger mass emission rates, 
tests conducted with both the AWP and the current work practice 
indicate the AWP, at this time, does not identify very small leaks and 
may not be able to identify if non-leaking/leakless equipment are truly 
nonleaking because the detection sensitivity of the optical gas imaging 
instrument is not sufficient.'' 73 FR 78204 (December 22, 2008). The 
EPA is soliciting information that would support the use of OGI for 
closed vent systems and equipment designated with no detectable 
emissions at new and existing process units, including comment on 
applying the proposed bimonthly OGI monitoring requirement on this 
equipment in place

[[Page 63183]]

of the NSPS VVa annual EPA Method 21 monitoring.
---------------------------------------------------------------------------

    \206\ For purposes of this standard, the EPA is referring to 
closed vent systems used equipment within process units at onshore 
natural gas processing plants. Closed vent systems associated with 
controlled storage vessels, wet seal centrifugal compressors, 
reciprocating compressors and pneumatic pumps are not included in 
this discussion and would demonstrate compliance with the no 
detectable emissions standard by EPA Method 21 (except for storage 
vessels), monthly AVO, or OGI monitoring during the fugitive 
emissions survey.
    \207\ See 73 FR 78199 (December 22, 2008).
---------------------------------------------------------------------------

    Finally, the EPA is proposing to retain the emission standards for 
PRDs found in 40 CFR 60.482-4a of NSPS VVa. This provision requires 
that PRDs be operated with no detectable emissions, except during 
pressure releases at new and existing process units. As stated above, 
the EPA is soliciting comment on the use of OGI to demonstrate that 
PRDs are meeting this operational emission standard.
2. EG OOOOc
    The EPA is proposing EG that include a presumptive methane standard 
that is the same as described above for the NSPS OOOOb for equipment 
leaks at existing onshore natural gas processing plants. Based on the 
analysis in section XII.H.2, the BSER for reducing GHGs from equipment 
leaks at new and existing onshore natural gas processing plants are the 
same.

I. Well Completions

    Based on our understanding that there are no advances in 
technologies or practices, which is summarized in section XII.I, the 
EPA is proposing to retain the REC and completion combustion 
requirements for reducing methane and VOC emissions from well 
completions of hydraulically fractured or refractured oil and natural 
gas wells, as they continue to reflect the BSER. These proposed 
standards are the same as those for natural gas and oil wells regulated 
in the 2012 NSPS OOOO and 2016 NSPS OOOOa, as amended in the 2020 
Technical Rule for VOC and proposed in section X.B.1 for methane.\208\ 
Because of the nature of well completions, any completion (or 
recompletion) is considered a new or modified well affected facility, 
therefore, the EPA does not believe there are existing well affected 
facilities to which a EG OOOOc presumptive standard for well 
completions would apply.
---------------------------------------------------------------------------

    \208\ See Docket ID No. EPA-HQ-OAR-2021-0317 for proposed 
redline regulatory text for 40 CFR 60.5375a as a reference for the 
specific well completion standards proposed for NSPS OOOOb.
---------------------------------------------------------------------------

J. Oil Wells With Associated Gas

    Associated gas originates at wellheads that also produce 
hydrocarbon liquids and occurs either in a discrete gaseous phase at 
the wellhead or is released from the liquid hydrocarbon phase by 
separation. There are no current NSPS requirements for this emission 
source. The EPA is proposing standards in the NSPS OOOOb to reduce 
methane and VOC emissions resulting from the venting of associated gas 
from oil wells.
1. NSPS OOOOb
    We are proposing standards to reduce methane and VOC emissions from 
each oil well that produces associated gas. Based on our analysis, 
which is summarized in section XII.J, we are proposing a standard under 
NSPS OOOOb that requires owners or operators of oil wells to route 
associated gas to a sales line. In the event that access to a sales 
line is not available, we are proposing that the gas can be used as an 
onsite fuel source, used for another useful purpose that a purchased 
fuel or raw material would serve, or routed to a flare or other control 
device that achieves at least 95 percent reduction in methane and VOC 
emissions. As discussed in section XII.J, the EPA is soliciting comment 
on how ``access to a sales line'' should be defined. An affected 
facility would be defined as any oil well that produces associated gas. 
The proposed rule would require that when using a flare, the flare must 
meet the requirements in 40 CFR 60.18 and that monitoring, 
recordkeeping, and reporting be conducted to ensure that the flare is 
constantly achieving the required 95 percent reduction. As discussed in 
section XII.J, the EPA is soliciting comment on an alternative affected 
facility definition that would exclude oil wells that route all 
associated gas to a sales line. The EPA is also soliciting comment and 
information that would support requirements using other strategies to 
reduce venting and flaring of associated gas from oil wells. The EPA is 
specifically requesting comment on whether the proposed requirements 
will incentivize the sale or productive use of captured gas, and if 
not, other methods that the EPA could use to incentivize or require the 
sale or productive use instead of flaring.
2. EG OOOOc
    The EPA is proposing presumptive standards for existing oil wells 
in this action that are the same as discussed above for new sources.

K. Sweetening Units

    Based on our understanding that no advances in technologies or 
practices are available to reduce SO2 emissions from 
sweetening units, as described in section XII.K, the EPA is proposing 
to retain the standards as it continues to reflect the BSER. These 
proposed standards are the same as those for sweetening units regulated 
in the 2016 NSPS OOOOa, and as amended in the 2020 Technical Rule.\209\
---------------------------------------------------------------------------

    \209\ See Docket ID No. EPA-HQ-OAR-2021-0317 for proposed 
redline regulatory text for 40 CFR 60.5375a as a reference for the 
specific well completion standards proposed for NSPS OOOOb.
---------------------------------------------------------------------------

L. Centralized Production Facilities

    The EPA is also proposing a new definition for ``centralized 
production facility,'' which is one or more permanent storage tanks and 
all equipment at a single stationary source used to gather, for the 
purpose of sale or processing to sell, crude oil, condensate, produced 
water, or intermediate hydrocarbon liquid from one or more offsite 
natural gas or oil production wells. This equipment includes, but is 
not limited to, equipment used for storage, separation, treating, 
dehydration, artificial lift, combustion, compression, pumping, 
metering, monitoring, and flowline. Process vessels and process tanks 
are not considered storage vessels or storage tanks. A centralized 
production facility is located upstream of the natural gas processing 
plant or the crude oil pipeline breakout station and is a part of 
producing operations. The EPA is proposing this definition to (1) 
specify how the fugitive emissions requirement apply to centralized 
production facilities, (2) specify how exemptions related to 40 CFR 
part 60, subpart K, Ka, or Kb (``NSPS Kb) may apply, and (3) specify 
what standards would apply to reciprocating and centrifugal compressors 
located at these facilities.
    First, the EPA is proposing to specify how the fugitive emission 
requirements apply to centralized production facilities. The 2016 NSPS 
OOOOa, as originally promulgated, provided that ``[f]or purposes of the 
fugitive emissions standards at 40 CFR 60.5397a, [a] well site also 
means a separate tank battery surface site collecting crude oil, 
condensate, intermediate hydrocarbon liquids, or produced water from 
wells not located at the well site (e.g., centralized tank 
batteries).'' 40 CFR 60.5430a. The inclusion of centralized tank 
batteries in the definition of well site was used to clarify the 
boundary of a well site for purposes of the fugitive emissions 
requirements. Further, in the RTC \210\ for the 2016 NSPS OOOOa we 
stated, ``[o]ur intent is to limit the oil and gas production segment 
up to the point of custody transfer to an oil and natural gas mainline 
pipeline (including transmission pipelines) or a natural gas processing 
plant. Therefore, the collection of fugitive emissions components 
within this boundary are a part of the well site.'' The EPA continues 
to define these facilities as a type of well site but is proposing a 
separate definition to provide further

[[Page 63184]]

clarity, especially as it relates to when these facilities are 
modified, and thus become subject to the fugitive emissions 
requirements in NSPS OOOOb. The EPA has determined it is appropriate to 
rename this site as a centralized production facility and to provide 
the specific definition above to avoid confusion with the storage 
vessel affected facility, of which applicability is determined for a 
tank battery, and to better specify the facility name based on the 
basic function the site performs (i.e., production operations).
---------------------------------------------------------------------------

    \210\ See Document ID No. EPA-HQ-OAR-2010-0505-7632 at page 4-
194.
---------------------------------------------------------------------------

    Second, the EPA has received questions related to whether NSPS Kb 
would apply to the storage vessels at centralized production 
facilities. There is an exemption in NSPS Kb for storage vessels in the 
producing operations that are below a specific size. Specifically, 40 
CFR 60.110(b)(4) exempts ``vessels with a design capacity less than or 
equal to 1,589.874 m\3\ used for petroleum or condensate stored, 
processed, or treated prior to custody transfer.'' This exemption is a 
revision of an exemption originally promulgated in 40 CFR part 60, 
subpart K (``NSPS K''). NSPS K ``does not apply to storage vessels for 
the crude petroleum or condensate stored, processed, and/or treated at 
a drilling and production facility prior to custody transfer.'' 40 CFR 
60.110(b). In that final rule the EPA explained that, ``[t]he storage 
of crude oil and condensate at producing fields is specifically 
exempted from the standard.'' 39 FR 9312 (March 8, 1974). While 
``producing fields'' were not explicitly defined, NSPS K defined the 
terms ``custody transfer'' and ``drilling and production facility''. 
For purposes of NSPS K, custody transfer means ``the transfer of 
produced crude petroleum and/or condensate, after processing and/or 
treating in the producing operations, from storage tanks or automatic 
transfer facilities to pipelines or any other forms of 
transportation.'' 40 CFR 60.111(g). Drilling and production facility 
means ``all drilling and servicing equipment, wells, flow lines, 
separators, equipment, gathering lines, and auxiliary 
nontransportation-related equipment used in the production of crude 
petroleum but does not include natural gasoline plants.'' 40 CFR 
60.111(h). The definition of ``custody transfer'' was later also 
incorporated into 40 CFR part 60, subpart Ka (``NSPS Ka''), NSPS Kb, 
and 40 CFR part 63, subpart HH (National Emission Standards for 
Hazardous Air Pollutants from Oil and Natural Gas Production 
Facilities).
    Instead of a categorical exemption for storage vessels located at 
drilling and production facilities, NSPS Ka, and subsequently NSPS Kb, 
adopted threshold-based exemptions that are based on the capacity of an 
individual storage vessel used to store petroleum (crude oil) or 
condensate prior to custody transfer. In NSPS Ka, the EPA stated 
``[t]his exemption applies to storage between the time that the 
petroleum liquid is removed from the ground and the time that custody 
of the petroleum liquid is transferred from the well or producing 
operations to the transportation operations'' 45 FR 23377 (April 4, 
1980). In NSPS Kb, the EPA further stated that ``[t]he promulgated 
standards for petroleum liquid storage vessels specifically exempted 
vessels with a capacity less than 420,000 gallons and storing petroleum 
(crude oil) and condensate prior to custody transfer (production 
vessels). The emission controls that are applicable to the storage 
vessels included in the standards being proposed are not applicable to 
production vessels.'' 49 FR 29701.
    The EPA finds it inappropriate to use the controls required by NSPS 
K, Ka, and Kb on storage vessels located in the production segment, 
especially where flash emissions are prevalent. Specifically, the NSPS 
K, Ka, and Kb control requirements include provisions allowing the use 
of floating roofs to reduce emissions from storage tanks. Floating 
roofs are not designed to store liquid (or gases) under pressure. 
Pressurized liquid sent to a storage vessel from a well or separator or 
other process that operates above atmospheric pressure may contain 
dissolved gases. These gases will be released or ``flash'' from the 
liquid as the fluid comes to equilibrium with atmospheric pressure 
within the storage vessel. The flash gas will either be released from 
gaps in the seal system or from ``rim vents'' on the floating roof. The 
rim vent may be an open tube or may be fitted with a low-pressure 
relief valve, but it is specifically designed to allow any gas 
entrained or dissolved in the storage liquid to be released above the 
floating roof. That is, floating roofs are not designed to prevent the 
release of flash gas, they are only designed to limit the 
volatilization of a liquid that occurs when the storage liquid is 
directly exposed with unsaturated air. Since a significant portion of 
emissions from storage vessels at well sites or centralized production 
facilities are from flash gas, floating roofs are much less effective 
at reducing storage vessel emissions than venting these emissions 
through a CVS to a control or recovery device.
    Further, it is the EPA's understanding that these centralized 
production facilities carry out the same operations that would be 
conducted at the individual well sites. Therefore, the EPA is proposing 
a definition of ``centralized production facility'' that clearly 
specifies these facilities are located within the producing operations. 
Therefore, if all other conditions are met (i.e., vessels with a design 
capacity less than or equal to 1,589.874 m\3\ used for petroleum or 
condensate stored, processed, or treated prior to custody transfer), 
storage vessels at these centralized facilities would meet the 
exemption criteria for NSPS Kb.
    Alternatively, the EPA is soliciting comment on whether it would be 
more appropriate to specify within the proposed NSPS OOOOb and EG OOOOc 
that storage vessels at well sites and centralized production 
facilities are subject to the requirements in NSPS OOOOb and EG OOOOc 
instead of NSPS K, Ka, or Kb. This alternative approach would eliminate 
the need for sources to determine if the storage vessel meets the 
exemption criteria specified in those subparts and instead focus on 
appropriate controls for the storage vessels based on the location and 
type of emissions likely present (e.g., flash emissions).
    Finally, the EPA is now proposing to define centralized production 
facilities separately from well sites because the number and size of 
equipment, particularly reciprocating and centrifugal compressors, is 
larger than standalone well sites which would not be included in the 
proposed definition of ``centralized production facilities'' above. In 
the 2016 NSPS OOOOa, the EPA exempted reciprocating and centrifugal 
compressors located at well sites from the applicable compressor 
standards.
    Reciprocating compressors that are located at well sites are not 
affected facilities under the 2016 NSPS OOOOa. The EPA previously 
excluded them because we found the cost of control to be unreasonable. 
81 FR 35878. However, as mentioned above, the EPA believes the 
definition of ``well site'' in NSPS OOOOa may cause confusion regarding 
whether reciprocating compressors located at centralized production 
facilities are also exempt from the standards. In our current analysis, 
described in section XII.E, we find it is appropriate to apply the same 
emission factors to reciprocating compressors located at centralized 
production facilities as those used for reciprocating compressors at 
gathering and boosting compressor stations. Given the results of that 
analysis, the EPA is proposing to apply the proposed NSPS OOOOb and 
presumptive standards in EG OOOOc to

[[Page 63185]]

reciprocating compressors located at centralized production facilities. 
The new definition above is intended to apply the results of the EPA's 
analysis. We believe that this new definition is necessary in the 
context of reciprocating compressors to distinguish between these 
compressors at centralized production facilities where the EPA has 
determined that the standard should apply, and these compressors at 
standalone well sites where the EPA has determined that the standard 
should not apply. See section XII.E for more details of those proposed 
standards.
    Similarly, wet seal centrifugal compressors that are located at 
well sites are not affected facilities under the 2016 NSPS OOOOa. The 
EPA previously excluded them because data available at the time did not 
suggest there were a large number of wet seal centrifugal compressors 
located at well sites. 81 FR 35878. In our current analysis, described 
in section XII.F, we find it is appropriate to apply the same emission 
factors to wet seal centrifugal compressors located at centralized 
production facilities as those used for these same compressors at 
gathering and boosting compressor stations. Given the results of that 
analysis, the EPA is proposing to apply the proposed NSPS OOOOb and 
presumptive standards in EG OOOOc to wet seal centrifugal compressors 
located at centralized production facilities. See section XII.F for 
more details of those proposed standards.

M. Recordkeeping and Reporting

    The EPA is proposing to require electronic reporting of performance 
test reports, annual reports, and semiannual reports through the 
Compliance and Emissions Data Reporting Interface (CEDRI). (CEDRI can 
be accessed through the EPA's Central Data Exchange (CDX) at https://cdx.epa.gov/.) A description of the electronic data submission process 
is provided in the memorandum Electronic Reporting Requirements for New 
Source Performance Standards (NSPS) and National Emission Standards for 
Hazardous Air Pollutants (NESHAP) Rules, available in the docket for 
this action. Performance test results collected using test methods that 
are supported by the EPA's Electronic Reporting Tool (ERT) as listed on 
the ERT website \211\ at the time of the test would be required to be 
submitted in the format generated through the use of the ERT or an 
electronic file consistent with the xml schema on the ERT website, and 
other performance test results would be submitted in portable document 
format (PDF) using the attachment module of the ERT. For semiannual and 
annual reports, the owner or operator would be required to use the 
appropriate spreadsheet template to submit information to CEDRI.
---------------------------------------------------------------------------

    \211\ https://www.epa.gov/electronic-reporting-air-emissions/electronic-reporting-tool-ert.
---------------------------------------------------------------------------

    The EPA is also proposing to allow owners and operators the ability 
to seek extensions for submitting electronic reports for circumstances 
beyond the control of the facility, i.e., for a possible outage in CDX 
or CEDRI or for a force majeure event, in the time just prior to a 
report's due date. The EPA is providing these potential extensions to 
protect owners and operators from noncompliance in cases where they 
cannot successfully submit a report by the reporting deadline for 
reasons outside of their control. The decision to accept the claim of 
needing additional time to report is within the discretion of the 
Administrator.
    Electronic reporting is required in the amended 2016 NSPS OOOOa, 
and the EPA believes that the electronic submittal of these reports in 
the proposed NSPS OOOOb will increase the usefulness of the data 
contained in those reports, is in keeping with current trends in data 
availability, will further assist in the protection of public health 
and the environment, and will ultimately result in less burden on the 
regulated community. Electronic reporting can also eliminate paper-
based, manual processes, thereby saving time and resources, simplifying 
data entry, eliminating redundancies, minimizing data reporting errors, 
and providing data quickly and accurately to the affected facilities, 
air agencies, the EPA, and the public. Moreover, electronic reporting 
is consistent with the EPA's plan \212\ to implement E.O. 13563 and is 
in keeping with the EPA's agency-wide policy \213\ developed in 
response to the White House's Digital Government Strategy.\214\
---------------------------------------------------------------------------

    \212\ EPA's Final Plan for Periodic Retrospective Reviews, 
August 2011. Available at: https://www.regulations.gov/document?D=EPA-HQ-OA-2011-0156-0154.
    \213\ E-Reporting Policy Statement for EPA Regulations, 
September 2013. Available at: https://www.epa.gov/sites/production/files/2016-03/documents/epa-ereporting-policy-statement-2013-09-30.pdf.
    \214\ Digital Government: Building a 21st Century Platform to 
Better Serve the American People, May 2012. Available at: https://obamawhitehouse.archives.gov/sites/default/files/omb/egov/digital-government/digital-government.html.
---------------------------------------------------------------------------

    In addition to the annual and semiannual reporting requirement, the 
EPA is soliciting comment on what elements, if any, are appropriate for 
more frequent reporting, and what mechanism would be appropriate for 
the collection and public dissemination of this information. For 
example, it may be appropriate to make information related to large 
emission events public in a timelier manner than the annual reporting 
period. Therefore, the EPA is soliciting comment on the appropriate 
mechanism to use for this type of report, including how the data would 
be reported, who would manage that reporting system, the frequency at 
which the data should be reported, the potential benefits of more 
frequent reporting for reducing emissions, the associated burden with 
this type of reporting and ways to mitigate that burden, and other 
considerations that should be taken into account.

N. Prevention of Significant Deterioration and Title V Permitting

    The pollutant we are proposing to regulate is GHGs, not methane as 
a separately regulated pollutant. As explained in section XV of this 
preamble, we are proposing to add provisions to NSPS OOOOb and EG 
OOOOc, analogous to what was included in the 2016 NSPS OOOOa and other 
rules regulating GHGs from electric utility generating units, to make 
clear in the regulatory text that the pollutant regulated by this rule 
is GHGs. The proposed addition of these and other provisions is 
intended to address some of the potential implications on the CAA 
Prevention of Significant Deterioration (PSD) preconstruction permit 
program and the CAA title V operating permit program.

XII. Rationale for Proposed NSPS OOOOb and EG OOOOc

    The following sections provide the EPA's BSER analyses and the 
resulting proposed NSPS to reduce methane and VOC emissions and the 
resulting proposed EG, which include presumptive standards, to reduce 
methane emissions from across the Crude Oil and Natural Gas source 
category. Our general process for evaluating BSER for the emission 
sources discussed below included: (1) Identification of available 
control measures; (2) evaluation of these measures to determine 
emission reductions achieved, associated costs, non-air environmental 
impacts, energy impacts and any limitations to their application; and 
(3) selection of the control techniques that represent

[[Page 63186]]

BSER.\215\ As discussed in the 2016 NSPS OOOOa, the available control 
technologies will reduce both methane and VOC emissions at the same 
time. The revised BSER analysis we have undertaken for the sources 
addressed in the proposed NSPS OOOOb continues to support this 
conclusion. CAA Section 111 also requires the consideration of cost in 
determining BSER. Section IX describes how the EPA evaluates the cost 
of control for purposes of this rulemaking. Sections XII.A through 
XII.I provide the BSER analysis and the resulting proposed NSPS and EG 
for the individual emission sources contemplated in this action. Please 
note that there are minor differences in some values presented in 
various documents supporting this action. This is because some 
calculations have been performed independently (e.g., NSPS OOOOb and EG 
OOOOc TSD calculations for NSPS OOOOb and EG OOOOc focused on unit-
level cost-effectiveness and RIA calculations focused on national 
impacts) and include slightly different rounding of intermediate 
values.
---------------------------------------------------------------------------

    \215\ In the context of developing the draft emissions 
guidelines contained herein, this general process also follows, and 
is intended to satisfy, certain requirements of EPA's implementing 
regulations for CAA section 111(d), namely the specific listed 
component of a draft EG contained in 40 CFR 60.22a(b)(2), and some 
elements of paragraph (b)(3).
---------------------------------------------------------------------------

    For this proposed EG the EPA is proposing to translate the degree 
of emission limitation achievable through application of the BSER 
(i.e., level of stringency) into presumptive standards.\216\ As 
discussed in each of the EG-specific subsections below, the EPA's 
evaluation of BSER in the context of existing sources utilized much of 
the same information as our BSER analysis for the NSPS. This is because 
within the oil and natural gas industry many of the control measures 
that are available to reduce emissions of methane from existing sources 
are the same as those control measures available to reduce VOC and 
methane emissions from new, modified, and reconstructed sources. By 
extension, many of the methane emission reductions achieved by the 
available control options, as well as the associated costs, non-air 
environmental impacts, energy impacts, and limitations to their 
application, are very similar if not the same for new and existing 
sources. Any relevant differences between new and existing sources in 
the context of available control measures or any other factors are 
discussed in the EG-specific subsections below.
---------------------------------------------------------------------------

    \216\ This is intended to satisfy certain elements of the 
requirements of EPA's implementing regulations found at 40 CFR 
60.22a(b)(3) and (5) with the exception of compliance times which 
the EPA discusses separately in section XVI.
---------------------------------------------------------------------------

    Where the EPA identified relevant distinctions between new and 
existing sources in the context of evaluating BSER, it was typically 
regarding the cost of control options. While many factors can cause 
differences in the cost of control between new and existing sources, 
the EPA would like to highlight two general concepts to illustrate how 
the oil and natural gas industry is unique. These concepts are the 
``size'' of the affected facility and the type of standards. First, 
affected facilities defined in any given NSPS can range from entire 
process units to individual pieces of equipment. For affected 
facilities comprised of an entire process unit, or very large processes 
or equipment, there can be significant differences between the cost of 
construction or modification for a new source as compared to the cost 
of a retrofit required for implementation of a control at an existing 
source. In the case of a new sources, there can be cost savings 
associated with the up-front planning for the installation of controls 
which cannot be achieved at existing sources that must instead retrofit 
already existing processes or equipment. This is particularly true of 
controls involving equipment changes or add-on control devices. In 
contrast, most affected facilities for which the EPA is proposing 
standards in NSPS OOOOb are more narrowly defined. For example, a 
pneumatic controller affected facility is generally defined as a single 
natural gas-driven pneumatic controller, which is a discrete and 
relatively small piece of equipment in a larger process. Another 
example is the reciprocating compressor affected facility which is 
defined as a single reciprocating compressor. As such, the EPA did not 
identify the same type of cost savings associated with the up-front 
planning of controls in the oil and gas sector as we might in the 
context of larger affected facilities. We believe this is one factor 
that led to costs being very similar for new and existing sources.
    Second, with regard to the type of standards, many of the standards 
proposed for NSPS OOOOb, and the presumptive standards proposed for EG 
OOOOc, are non-numerical standards, such as work practice standards, 
that require limited or no significant physical modifications. The EPA 
found that costs for these non-numerical standards would typically not 
differ between new and existing sources because the work practice could 
be implemented in both contexts without the need to first install or 
retrofit any equipment. Put another way, a work practice tends to 
operate in the same manner regardless of whether the site is new or 
existing, and existing sites typically do not need to take any 
preliminary steps in order to implement the work practice. For these 
reasons, many of the proposed presumptive standards for EG OOOOc 
discussed in the following sections mirror the proposed standards 
identified based on the BSER analyses for NSPS OOOOb.

A. Proposed Standards for Fugitive Emissions From Well Sites and 
Compressor Stations

1. NSPS OOOOb
    There are many potential sources of fugitive emissions throughout 
the Crude Oil and Natural Gas Production source category. Fugitive 
emissions occur when connection points are not fitted properly or when 
seals and gaskets start to deteriorate. Changes in pressure and 
mechanical stresses can also cause components or equipment to emit 
fugitive emissions. Poor maintenance or operating practices, such as 
improperly reseated pressure relief valves (PRVs) or worn gaskets and 
springs on thief hatches on controlled storage vessels are also 
potential causes of fugitive emissions. Additional sources of fugitive 
emissions include agitator seals, connectors, pump diaphragms, flanges, 
instruments, meters, open-ended lines, PRDs such as PRVs, pump seals, 
valves or controlled liquid storage tanks.
    In the 2021 GHGI, the methane emissions for 2019 from fugitive 
emissions in the Crude Oil and Natural Gas source category were 96,000 
metric tons methane for petroleum systems and 351,500 metric tons for 
natural gas systems. These levels represent 6 percent of the total 
methane emissions estimated from all petroleum systems sources (i.e., 
exploration through refining) and 5 percent of all methane emissions 
from natural gas systems (i.e., exploration through distribution). In 
addition, fugitive emissions may be represented in other categories of 
the GHGI production segment; for example, a portion of fugitive 
emissions (as defined in this action) is also expected to be related to 
fugitive emissions from tank thief hatches, and thief hatches on 
controlled storage vessels, and those emissions are included in the 
emissions estimates for storage vessels in the GHGI.
    In the 2016 NSPS OOOOa, the EPA promulgated standards to control 
GHGs (in the form of limitations on methane emissions) and VOC 
emissions from fugitive emissions components located at well sites and 
compressor stations. These standards required a fugitive

[[Page 63187]]

emissions monitoring and repair program, where well sites and 
compressor stations had to be monitored semiannually and quarterly, 
respectively.
a. Fugitive Emissions From Well Sites
    Oil and natural gas production practices and equipment vary from 
well site to well site. A well site can serve one well or multiple 
wells. Some production sites may include only a single wellhead that is 
extracting oil or natural gas from the ground, while other sites may 
include multiple wellheads with a number of operations such as 
production, extraction, recovery, lifting, stabilization, separation 
and/or treating of petroleum and/or natural gas (including condensate). 
In addition, the 2016 NSPS OOOOa definition of well site also includes 
centralized tank batteries for purposes of the fugitive emissions 
requirements because, like storage vessels at well sites, centralized 
tank batteries collect crude oil, condensate, intermediate hydrocarbon 
liquids, or produced water from wells; therefore, ``excluding tank 
batteries not located at the well site could incentivize some owners or 
operators to place new tank batteries further away from well sites to 
make use of such an exemption.'' \217\ The equipment to perform these 
production operations (including piping and associated components, 
compressors, generators, separators, storage vessels, and other 
equipment) has components that may be sources of fugitive emissions. 
Therefore, the number of components with the potential for fugitive 
emissions can vary depending on the number of wells and the number of 
major production and processing equipment at the site. Another factor 
that impacts the operations at a well site, and the resulting fugitive 
emissions potential, is the nature of the oil and natural gas being 
extracted. This can range from well sites that only extract and handle 
``dry'' natural gas to those that extract and handle heavy oil.
---------------------------------------------------------------------------

    \217\ See Document ID No. EPA-HQ-OAR-2010-0505-7632 at page 4-
221.
---------------------------------------------------------------------------

    In both the 2016 NSPS OOOOa and subsequent amendments in the 2020 
Technical Rule, the EPA relied on a model plant approach to estimate 
emissions from well sites. Model plants were developed to provide a 
representation of well sites across the spectrum. Separate production-
based model plants using component counts to determine baseline 
emissions were developed. The basic approach used was to assign a 
number of specific equipment types for each well site model plant and 
then to estimate the number of components based on assigned numbers of 
components per equipment type. Primarily, the well site model plants 
utilized information from the DrillingInfo HPDI[supreg] database,\218\ 
the 1996 EPA/GRI Study,\219\ EPA's GHG Inventory, and GHGRP subpart W. 
Fugitive model plants were originally developed for the 2015 NSPS OOOOa 
proposed rule (80 FR 56614, September 18, 2015) and evolved over time 
in response to new information and public comments. More information on 
the history of the model plant development can be found in the 2015 
NSPS Proposal TSD,\220\ the 2016 NSPS Final TSD,\221\ the 2018 NSPS 
Proposal TSD,\222\ and the 2020 NSPS Final TSD.\223\
---------------------------------------------------------------------------

    \218\ Drilling Information, Inc. 2014. DI Desktop. 2014 
Production Information Database.
    \219\ Gas Research Institute (GRI)/U.S. EPA. Research and 
Development, Methane Emissions from the Natural Gas Industry, Volume 
8: Equipment Leaks. June 1996 (EPA-600/R-96-080h).
    \220\ EPA-HQ-OAR-2010-0505-5021.
    \221\ EPA-HQ-OAR-2010-0505-7631.
    \222\ EPA-HQ-OAR-2017-0483-0040.
    \223\ EPA-HQ-OAR-2017-0483-2290.
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    In this proposal, the EPA is shifting away from using model plants 
for well sites for the BSER analysis and is instead using an individual 
site-level emission-calculation approach in order to better 
characterize and take into account the differences at individual well 
sites that can lead to a vast range in the magnitude of fugitive 
emissions, which a model plant cannot do. Provided below is a more 
detailed explanation of the issues concerning the previous model plant 
approach, followed by a description of the site-specific baseline 
emission calculation approach, which is similar to the State of 
Colorado's LDAR program.
    In the 2020 Technical Rule, the EPA created separate model plants 
to represent fugitive emissions from low production well sites (those 
producing 15 boe or less per day) and non-low production well sites, as 
it was generally assumed that low producing sites would have fewer 
major production and processing equipment and thus lower fugitive 
emissions. This prior estimate of baseline emissions was calculated 
using model plant site designs with assumed populations of major 
production and processing equipment and fixed fugitive emissions 
component counts. While the estimated baseline emissions from the two 
model plants differ due to the difference in the assumed populations of 
major production and processing equipment and fixed fugitive emissions 
component counts, the estimated baseline emissions were intended to 
represent the baseline emissions for all well sites represented by each 
model plant. Since that rulemaking, further analysis of existing and 
new information indicates that there is significant variation in the 
well characteristics, type of oil and gas products and production 
levels, gas composition, operations, and types and quantity of 
equipment at well sites across the U.S. The TSD for this action further 
describes existing data and new information received since the 2020 
Technical Rule that have been evaluated by the EPA to arrive at the 
conclusion that there is no one-size-fits-all approach to predicting 
emissions from well sites and that the emissions vary greatly, in ways 
that bear little correlation to production levels alone. For example, 
site-level methane emissions data from comprehensive studies sampled 
across several different regions at numerous well sites, shows a wide 
range of methane emissions (i.e., ranging from as low as 0 to as high 
as 1,200 tpy for marginal or low production wells). Additionally, 
recently obtained ICR data indicate that actual component counts at 
well sites with equipment could be higher than those estimated by model 
plants for low and non-low production, e.g., EPA's non-low model plant 
could be underestimating number of wells, tanks and separators; and 
similar observations were made for low production based on this data. 
Contrary to previous general assumptions, information reviewed also 
shows that it is not necessarily the case that fugitive emissions from 
sites with lower production have lower emissions than sites with higher 
production. In fact, it is quite possible that the inverse can be true 
(i.e., lower producing sites could have higher emissions and inversely, 
higher producing sites could have lower emissions.) More information 
can be found in the NSPS OOOOb and EG TSD for this proposal.
    Therefore, the EPA has concluded that the previous model plant 
approach, which was based on two production levels (equal/above or 
below 15 boe per day) and the estimated equipment types and numbers 
associated with each of the two production levels, may not be 
reflective of the actual baseline fugitive emissions from well sites. 
Further, the potential for fugitive emissions at any given site is 
impacted more by the number and type of equipment at the site and 
maintenance practices, which can vary widely among well sites with low 
production.\224\ Given these

[[Page 63188]]

limitations in utilizing model plants to analyze fugitive emission 
reduction programs at well sites with widely varying configurations, 
operations, and production levels, we find it appropriate to shift away 
from using model plants and instead rely on the potential fugitive 
emissions at the individual site in our BSER analysis and resulting 
proposed standards. Therefore, this new analysis, which is described 
below, is conducted on this basis.
---------------------------------------------------------------------------

    \224\ See https://pubs.acs.org/doi/10.1021/acs.est.0c02927, 
https://data.permianmap.org/pages/flaring, and https://www.edf.org/sites/default/files/documents/PermianMapMethodology_1.pdf.
---------------------------------------------------------------------------

    This site-specific baseline emissions calculation approach is 
similar to the State of Colorado's LDAR program. The concept is that 
each site calculates its baseline methane emissions for all the 
equipment at the site, the number and type of equipment at the well 
site, the number of fugitive emissions components associated with each 
piece of equipment, and the site-specific gas composition. The fugitive 
monitoring frequency would be based on the baseline site-specific 
methane emissions level calculated based on this information. This 
calculation is described in detail in section XI.A.2. We believe that 
this approach will more accurately depict the emissions profile at each 
individual well site. As a result, the EPA is conducting the BSER 
analysis based on site-level baseline methane emissions, where the 
analysis is performed in increments of 1 tpy of site-level baseline 
methane emissions as discussed more below.
    During the rulemaking for the 2016 NSPS OOOOa, the EPA analyzed two 
options for reducing fugitive methane and VOC emissions at well sites: 
A fugitive emissions monitoring program based on individual component 
monitoring using EPA Method 21 for detection combined with repairs and 
a fugitive emissions monitoring program based on the use of OGI 
detection combined with repairs. Finding that both methods achieve 
comparable emission reduction but OGI was more cost effective, the EPA 
ultimately identified semiannual monitoring of well sites using OGI as 
the BSER. 81 FR 35856 (June 3, 2016). While there are several new 
fugitive emissions technologies under development, the EPA needs 
additional information to fully characterize the cost, availability, 
and capabilities of these technologies, and they are therefore not 
being evaluated as potential BSER at this time. However, we are 
proposing the use of these technologies as an alternative screening 
method as described in section XI.A.5. For this analysis for both the 
NSPS and the EG, we re-evaluated the use of OGI as BSER. In the 
discussion below, we evaluate OGI control options based on varying the 
frequency of conducting the survey and fugitive emissions repair 
threshold (i.e., the visible identification of methane or VOC when an 
OGI instrument is used). For this analysis, we considered biennial, 
annual, semiannual, quarterly, and monthly survey frequency for well 
sites.
    The regulatory concept for the proposed NSPS OOOOb is that the 
required frequency of fugitive monitoring would be based on total site 
baseline methane emissions. At well sites, the composition of gas is 
predominantly methane (approximately 70 percent on average). Therefore, 
as shown in our analysis, compared to VOC, methane better reflects the 
baseline emission level where it is cost effective to regulate both 
methane and VOC fugitive emissions at well sites. For this reason, we 
chose to use methane as the threshold for our determination.
    For the BSER analyses, we selected for evaluation total site-wide 
methane emissions increments of 1 tpy of site-level baseline methane 
emissions ranging from 1 tpy to 50 tpy. The EPA acknowledges that the 
site-level baseline methane emissions calculated may not account for 
the presence of large emission events when they occur. However, the EPA 
has found it inappropriate to apply a factor that assumes every site is 
experiencing a large emission event annually based on information 
suggesting that only a small percentage of sites experience these 
events at any given time.\225\
---------------------------------------------------------------------------

    \225\ Brandt, A.R., Heath, G.A., Cooley, D. (2016). Methane 
Leaks from Natural Gas Systems Follow Extreme Distributions. 
Environ. Sci. Technol. 50, 12512, https://pubs.acs.org/doi/abs/10.1021/acs.est.6b04303; Zavala-Araiza, D., Alvarez, R., Lyon, D, et 
al. (2016). Super-emitters in natural gas infrastructure are caused 
by abnormal process conditions. Nat Commun 8, 14012 (2017). https://www.nature.com/articles/ncomms14012; Zavala-Araiza, D., Lyon, D., 
Alvarez, R. et al. (2015). PNAS 112, 15597. https://www.pnas.org/content/112/51/15597.
---------------------------------------------------------------------------

    In 2015, we evaluated the potential emission reductions from the 
implementation of an OGI monitoring program where we assigned an 
emission reduction of 40, 60, and 80 percent to annual, semiannual, and 
quarterly monitoring survey frequencies, respectively. The EPA re-
evaluated the control efficiencies under different monitoring 
frequencies for the 2020 Technical Rule based on comments received on 
the 2018 proposal and concluded that the assigned control efficiencies 
described above can be expected from the corresponding monitoring 
frequencies using OGI.\226\ No other information reviewed since that 
time indicates that the assigned reduction frequencies are different 
than previously established and the reduction efficiencies are 
consistent with what current information indicates. In addition, we 
also evaluated biennial survey frequency for well sites assuming an 
achievable reduction frequency of 30 percent, and monthly monitoring 
where information evaluated indicated monthly OGI monitoring has the 
potential of reducing emissions up towards 90 percent.
---------------------------------------------------------------------------

    \226\ See 85 FR 57412 and section 2.4.1.1 of the 2020 TSD.
---------------------------------------------------------------------------

    It is worth noting that these calculations are based on the 
expected reductions from ``typical'' component equipment leaks that 
occur with well-maintained sites. The EPA is aware of situations where 
equipment malfunctions related to equipment components can cause large 
emission events that are described in detail in section XII.A.5. In 
these cases, we expect the emission reductions associated with the 
different monitoring frequencies evaluated would be significantly 
higher than assumed above and is the reason we solicit comment on the 
proposed alternative screening program using advanced measurement 
technologies to identify and quantify large emission sources. Given the 
intermittent and stochastic nature of large emission events, it is 
difficult to apply emission factors that predict the probability of a 
site experiencing these events within any timeframe. As stated above, 
the EPA finds it inappropriate to apply a factor that assumes every 
site is experiencing a large emission event annually given the 
available data. However, we recognize that identifying and stopping 
these large emission events is a central purpose of the monitoring 
requirements proposed in this document, and that quantifying the 
pollution reduction benefits associated with addressing these large 
emission events is important to fully capture the benefits and cost-
effectiveness of our proposed fugitive emissions monitoring 
requirements. We also acknowledge there is substantial ongoing research 
on large emission events that may further inform the EPA's 
calculations, including the potential to develop factors that take into 
account a distribution of emissions across well sites and the 
associated emissions reductions achieved when large emission events are 
included in the calculation.
    We evaluated the costs of a monitoring and repair program under 
various monitoring frequencies. For

[[Page 63189]]

well sites, the capital costs associated with the fugitives monitoring 
program were estimated to be $1,030 per well site. These capital costs 
include the cost of developing the fugitive emissions monitoring plan 
and purchasing or developing a recordkeeping data management system 
specific to fugitive emissions monitoring and repair. Consistent with 
the analyses used for the 2016 NSPS OOOOa and 2020 Technical Rule, the 
EPA assumes that each company will develop a monitoring plan and 
recordkeeping system that covers a company-defined area, which is 
assumed to include 22 well sites. This assumption is used because there 
are several elements of the fugitive monitoring program that are not 
site-specific. The total company-defined area (22 well site) capital 
costs are divided evenly to arrive at the $1,030 capital cost per well 
site estimate.
    When evaluating the annual costs of the fugitive emissions 
monitoring and repair requirements (i.e., monitoring, repair, repair 
verification, data management licensing fees, recordkeeping, and 
reporting), the EPA considers costs at the individual site level. 
Estimates for these costs were updated extensively as part of the 2020 
Technical Rule, and the EPA has made further updates for this proposal 
based on more recent information. With these updates, the estimated 
annual costs of the fugitive emissions program at well sites are 
estimated to range from $2,490 for biennial monitoring to $8,140 for 
monthly monitoring.\227\ These total annual costs include annualization 
of the up-front cost at 7 percent interest rate over 8 years. We note 
these costs are representative of the average annual costs expected at 
well sites, where larger sites may have larger costs associated with 
longer surveys or potentially more repairs, while smaller sites may 
experience the opposite with shorter surveys or potentially less 
repairs. Therefore, we believe the costs developed for well sites are 
representative of OGI fugitives monitoring program costs and reflect 
the best information available at this time.
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    \227\ As a comparison, the annualized costs for fugitive 
emissions monitoring and repair at well sites were estimated to 
range from $1,900 to $3,500 for annual to quarterly monitoring, 
respectively, in the 2020 Technical Rule. See 2020 TSD, attachment 5 
at Document ID No. EPA-HQ-OAR-2017-0483-2290.
---------------------------------------------------------------------------

    The EPA requests comment on its range of cost estimates for an OGI 
fugitives monitoring program. The EPA believes that there will be 
sufficient supply of OGI equipment and available OGI camera operators 
for industry to conduct all required monitoring, upon the effective 
date of the NSPS OOOOb and the subsequent implementation of the EG 
OOOOc. However, the EPA requests additional information on this 
capacity and whether there is a likelihood of shortages in the early 
years of the program that might raise costs. The EPA is also requesting 
comment on the proposed appendix K and whether the proposed training, 
certification, and audit provisions are appropriate and do not place 
undue burden on the ability of industry to satisfy the regulatory 
requirements.
    At well sites, there are savings associated with the gas not being 
released. The value of the natural gas saved is assumed to be $3.13 per 
Mcf of recovered gas. Annual costs were also calculated considering 
these savings.
    As discussed in section XI.C, natural gas-driven intermittent 
pneumatic controllers are designed to vent during actuation only, but 
these devices are known to malfunction and operate incorrectly, which 
causes them to release natural gas to the atmosphere when idle. The EPA 
is proposing a zero VOC and methane emissions standard for natural gas-
driven intermittent pneumatic controllers. However, for sites in Alaska 
located in the production segment (well sites, gathering and boosting 
stations, and centralized tank batteries) and in the transmission and 
storage segment that do not have electricity, the EPA is proposing a 
standard wherein intermittent natural gas-driven pneumatic controllers 
only vent during actuation and not when idle. See section XII.C on 
pneumatic controllers for a full explanation of this standard. While 
these intermittent controllers are their own separate affected 
facility, we are proposing that they be monitored in conjunction with 
the fugitive emissions components located at the same well site to 
verify proper actuation and that venting does not occur during idle 
times.
    We created a matrix that includes, for each site-wide methane 
emission level, the capital (up front) cost, annual costs (with and 
without the consideration of savings), emission reductions for methane 
and VOC, and cost effectiveness (dollar per tons of emission 
reduction). Cost effectiveness was calculated using two approaches; the 
single pollutant approach where all the costs are assigned to the 
reduction of one pollutant; and the multipollutant approach, where half 
the costs are assigned to the methane reduction and half to the VOC 
reduction, see discussion in preamble section IX. This was repeated for 
each site-wide methane emissions level for each monitoring frequency. 
There were several trends shown in this matrix. As noted above, the 
annual cost for each individual monitoring frequency is applied to all 
site-wide emission levels when evaluating that frequency. Therefore, as 
the emissions (and potential emission reductions) increased, the 
fugitive emissions monitoring became more cost-effective. For example, 
for semiannual monitoring, the cost effectiveness ranged from $5,300 
per ton of methane reduced (for a 1 tpy site-wide methane site) to $100 
per ton (for a 50 tpy site-wide methane site). Also, because the 
emission reduction increase was greater than the cost increase with 
increasing monitoring frequency, the fugitive emissions monitoring 
became more cost-effective with increasing monitoring frequency. For 
example, for a 10 tpy site-wide methane site, the methane cost 
effectiveness for annual monitoring was $750 per ton, $530 per ton for 
semiannual monitoring, and $525 per ton for quarterly monitoring. This 
trend did not extend to monthly monitoring, as the cost of monthly 
monitoring increases significantly (almost double) compared to 
quarterly monitoring, while the emission reduction only increased by 10 
percent. The complete matrix is available in the NSPS OOOOb and EG TSD 
for this rulemaking.
    The matrix shows that, on a multipollutant basis, both semiannual 
and quarterly monitoring at well sites with baseline emissions as low 
as 2 tpy is cost-effective, and that at 3 tpy, both semiannual and 
quarterly monitoring are cost-effective based on the methane emissions 
alone. Cost-effectiveness, however, is not the only relevant factor in 
setting the BSER, particularly for a source as numerous and diverse as 
well sites. We estimate that there will be approximately 21,000 new 
wells each year (and 410,000 existing wells) to which the proposed 
fugitive emissions requirements will apply.\228\ Various studies 
demonstrate that the vast majority of emissions come from a relatively 
small subset of wells.\229 230\

[[Page 63190]]

The EPA would like to ensure that resources and effort are focused on 
those wells that emit the most methane and VOC. Moreover, given the 
diversity of ownership, while our cost assumption that distributes the 
costs of recordkeeping evenly across 22 sites within a company-defined 
area is a reasonable estimate for the population as a whole, it may 
underestimate the costs and therefore overestimate the cost-
effectiveness for owners with fewer than 22 well sites (and conversely, 
underestimate cost-effectiveness for owners with more than 22 well 
sites). In order to best focus resources and effort on the well sites 
with the greatest emissions and more accurately capture costs, 
particularly for owners with fewer well sites, the EPA requests comment 
on the number of wells that likely emit at each baseline emissions 
level, and the baseline emissions level of wells generally owned by 
owners with few wells. The EPA anticipates that it may refine its BSER 
determination for well sites through its supplemental proposal based on 
the information gathered from commenters.
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    \228\ Estimated well counts are based on non-wellhead only 
sites. Based on information provided by API, we assume that 27% of 
sites are wellhead only; see Memoranda for Meetings with the 
American Petroleum Institute (API), September 23, 2021, located at 
Docket ID No. EPA-HQ- OAR-2021-0317. Absent additional information, 
we also assume that 27% of wells are wellhead only. The estimated 
new well count reflects the arithmetic average of well counts over 
the analysis horizon in the RIA, 2023-2035. The estimated existing 
well count reflects the total in 2026, which is the first year that 
we estimate impacts for the emissions guidelines.
    \229\ Brandt, A., Heath, G., Cooley, D. (2016) Methane leaks 
from natural gas systems follow extreme distributions. Environ. Sci. 
Technol., DOI: 10.1021/acs.est.6b04303.
    \230\ Zavala-Araiza, D., Alvarez, R., Lyon, D, et al. (2016). 
Super-emitters in natural gas infrastructure are caused by abnormal 
process conditions. Nat Commun 8, 14012 (2017). https://www.nature.com/articles/ncomms14012.
---------------------------------------------------------------------------

    Taking these factors into account, and as explained in more detail 
below, the EPA proposes to conclude that (1) BSER for well sites with a 
baseline site-wide emissions level of less than 3 tpy is no regular 
monitoring, but that to help ensure that these sites actually emit at 
less than 3 tpy, a one-time survey (following each calculation of site-
level baseline methane emissions) would be required to ensure that any 
abnormalities are addressed; (2) BSER for well sites with a baseline 
site-wide emissions level of 3 tpy or greater is quarterly monitoring. 
Because of the uncertainties discussed above, and as explained in more 
detail below, the EPA further co-proposes to conclude that BSER for 
well sites with a baseline site-wide emissions level of 3 tpy or 
greater and less than 8 tpy is semiannual monitoring. Our co-proposal 
is the same as our main proposal with regard to well sites whose 
baseline site-wide emissions are less than 3 tpy (no regular 
monitoring, but a one-time survey) and whose emissions are 8 tpy or 
greater (quarterly monitoring). The EPA estimates that a majority of 
fugitive emissions (approximately 86%) can be attributed to wells with 
site-wide baseline emissions of 3 tpy or greater, where 54% can be 
attributed to wells with site-wide baseline emissions of 8 tpy or 
greater.\231\
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    \231\ Percentages were estimated for the baseline scenario in 
the RIA for the 2030 analysis year by combining the bin percentages 
presented in RIA Table 2-4 with the projected well site activity 
data documented in the RIA.
---------------------------------------------------------------------------

    Proposed BSER for Well Sites with Baseline Emissions Less Than 3 
tpy. As noted, in both our main proposal and our co-proposal, we 
propose to conclude that BSER for well sites with baseline emissions of 
less than 3 tpy is no regular monitoring, but a one-time survey to help 
ensure that these sites actually emit at less than 3 tpy.
    Based on the matrix described above, the EPA determined that where 
total site baseline methane emissions are 2 tpy, semiannual and 
quarterly monitoring costs approximately $2,700/ton methane reduced, 
while biennial and annual monitoring costs approximately $4,000/ton 
methane reduced. The costs for VOC reductions range from $10,000 to 
$15,000/ton VOC reduced for quarterly to biennial monitoring, 
respectively. These costs are outside the range of what we are 
proposing to consider cost effective on a single-pollutant basis for 
both methane and VOC. See Section IX.B. However, when considered on a 
multipollutant basis, the costs of semiannual and quarterly monitoring 
are approximately $1,350 per ton methane reduced, and approximately 
$5,000 per ton of VOC, which we do consider cost-effective. Thus, for 
sites with total baseline methane emissions of 2 tpy, we conclude that 
regular monitoring at semiannual or quarterly frequencies would be 
cost-effective.\232\
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    \232\ The NSPS OOOOb and EG OOOOc TSD also provide costs for 
monitoring at 1 tpy, which is not considered cost-effective at any 
frequency evaluated.
---------------------------------------------------------------------------

    We do not propose to conclude that routine monitoring with OGI is 
the BSER for sites with baseline emissions of less than 3 tpy, however, 
for several reasons. While the estimates for semiannual and quarterly 
monitoring are within what we consider to be cost effective for well 
sites with baseline emissions of 2 tpy, in light of the large cohort of 
relatively lower-emitting sites, we are concerned that our cost 
effectiveness estimates may not accurately capture the costs, and 
therefore cost-effectiveness, of routine monitoring with OGI for 
businesses that own relatively few well sites. Throughout the 
development of the 2016 NSPS OOOOa, and in subsequent analyses and 
rulemaking actions, industry stakeholders have consistently stated that 
the fugitive monitoring requirements are particularly burdensome for 
smaller entities that own fewer well sites. The EPA believes that many 
of these smaller entities are likely to own well sites with baseline 
emissions of less than 3 tpy, a category that tends to include smaller 
and less complex facilities with few or no major pieces of production 
and processing equipment.\233\ And as noted, the EPA would like to 
ensure that resources and effort are focused on well sites with 
significant emissions. Given the possibility that our cost-
effectiveness analysis has overestimated the average number of sites, 
and therefore underestimated the cost-effectiveness, for this cohort of 
well sites, the EPA is proposing no regular monitoring at sites with 
baseline site-wide emissions of less than 3 tpy.
---------------------------------------------------------------------------

    \233\ Anna M. Robertson, Rachel Edie, Robert A. Field, David 
Lyon, Renee McVay, Mark Omara, Daniel Zavala-Araiza, and Shane M. 
Murphy. ``New Mexico Permian Basin Measured Well Pad Methane 
Emissions Are a Factor of 5-9 Times Higher Than U.S. EPA 
Estimates.''
    Environmental Science & Technology 2020 54 (21), 13926-13934. 
DOI: 10.1021/acs.est.0c02927.
---------------------------------------------------------------------------

    While the EPA is proposing to conclude that BSER for well sites 
with total site-level baseline methane emissions less than 3 tpy is no 
regular monitoring, we believe it is essential to ensure that well 
sites in this monitoring tier are operating in a well-controlled 
manner, and are not experiencing leaks or malfunctions that would cause 
their emissions to exceed 3 tpy. Therefore, the EPA is proposing a 
requirement for owners and operators to conduct a survey, and perform 
repairs as needed, to demonstrate that the well site is free of leaks 
or malfunctions and is therefore operating in a manner consistent with 
the baseline methane emissions calculation.\234\ This survey could 
employ any method available that would demonstrate the actual emissions 
are consistent with the baseline calculation, including, but not 
limited to, the use of OGI, EPA Method 21 (which includes provisions 
for a soap bubble test), or alternative methane detection technologies 
like those discussed in the proposed screening alternative in section 
XI.A.5.
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    \234\ We anticipate that during the survey to confirm their 
baseline methane emissions and thus exemption status, sources would 
also repair the leaks found, consistent with our understanding of 
the standard industry practice.
---------------------------------------------------------------------------

    The EPA seeks comment on all aspects of this proposed BSER 
determination, including information, data, and analysis that would 
shed further light on the factors and concerns just expressed and that 
would support the establishment of ongoing monitoring requirements at 
the cohort of sites with baseline methane emissions below 3 tpy. Among 
other things, the EPA seeks

[[Page 63191]]

comment on the ownership profile of well sites with site-wide baseline 
emissions less than 3 tpy, the extent to which well sites in this 
cohort are owned by firms that own relatively few wells, and the 
relative economic costs associated with requiring regular OGI 
monitoring at these wells. The EPA also seeks information that would 
improve our understanding of the overall number of wells that would 
fall in this cohort of sites, and the contribution these wells make to 
overall fugitive emissions. And the EPA seeks comment on our estimates 
of the costs and emission reduction associated with OGI monitoring at 
this cohort of sites, or other data and analysis that would provide 
support for regular OGI monitoring at these sites. In addition, the EPA 
notes that the advanced measurement technologies that form the basis of 
our proposed alternative screening option in section XI.A.5 could be 
particularly well-suited for rapidly and cost-effectively detecting 
recurrences of large emitting events at sites with baseline emissions 
below 3 tpy. Accordingly, the EPA seeks comment that could inform 
whether to require the use of these technologies for ongoing monitoring 
at this cohort of sites, including information on the capabilities of 
these emerging technologies, methodologies for their use, and the costs 
and emission reductions associated with using these advanced 
measurement technologies as part of a mandatory monitoring regime. If 
appropriate, and based on input received during the comment period, the 
EPA may consider further addressing monitoring requirements for sites 
with baseline emissions below 3 tpy as part of a supplemental proposal.
    Additionally, the EPA is soliciting comment on different criteria, 
such as the number of well sites owned by a specific owner, that could 
better account for factors that may affect the costs of fugitive 
emissions monitoring. As noted, while the EPA has presented costs on an 
individual site-level, we have also distributed the costs of 
recordkeeping evenly across an assumed 22 sites within a company-
defined area. While this may be appropriate for companies with larger 
ownership, it is likely underestimating the cost (and overestimating 
the cost-effectiveness) on owners with fewer sites. Information 
provided on small businesses, including ownership thresholds, could be 
used to further determine differences in OGI monitoring requirements at 
well sites through a supplemental proposal.
    Further, the EPA is soliciting comment on whether the presence of 
specific major production and processing equipment types at a well site 
warrants a separate monitoring frequency consideration even where the 
calculated total site-level baseline methane emissions are below 3 tpy. 
As mentioned throughout this preamble, the EPA is concerned about the 
presence of large emission events, which various studies have shown are 
most often attributed to specific equipment. This equipment includes 
separators paired with onsite storage vessels, combustion devices, and 
intermittent pneumatic controllers.235 236 237 Therefore, 
the EPA is soliciting comment on whether well sites with these specific 
types of equipment present must conduct at least semiannual monitoring, 
regardless of the total site-level baseline methane emissions 
calculated, including those sites calculated below 3 tpy.
---------------------------------------------------------------------------

    \235\ Id.
    \236\ Tyner, David R., Johnson, Matthew R., ``Where the Methane 
Is--Insights from Novel Airborne LiDAR Measurements Combined with 
Ground Survey Data.'' Environmental Science & Technology 2021 55 
(14), 9773-9783. DOI: 10.1021/acs.est.1c01572.
    \237\ Rutherford, J.S., Sherwin, E.D., Ravikumar, A.P. et al. 
Closing the methane gap in US oil and natural gas production 
emissions inventories. Nat Commun 12, 4715 (2021). https://doi.org/10.1038/s41467-021-25017-4.
---------------------------------------------------------------------------

    Finally, the EPA believes there is a subset of well sites (i.e., 
wellhead only well sites) that will never have baseline methane 
fugitive emissions of 3 tpy or greater. Therefore, the proposed rule 
would not define these sites as affected facilities, thus removing the 
need for these sites to determine baseline emissions. As defined in the 
2020 Technical Rule, a ``wellhead only well site'' is ``a well site 
that contains one or more wellheads and no major production and 
processing equipment.'' The term ``major production and processing 
equipment'' is defined as including reciprocating or centrifugal 
compressors, glycol dehydrators, heater/treaters, separators, and 
storage vessels collecting crude oil, condensate, intermediate 
hydrocarbon liquids, or produced water. As described earlier in this 
section, sites will calculate their baseline methane emissions using a 
combination of population-based emission factors and storage vessel 
emissions. The population-based emission factors include emissions from 
wellheads, reciprocating and centrifugal compressors, glycol 
dehydrators, heater/treaters, separators, natural gas-driven pneumatic 
pumps, and natural gas-driven pneumatic controllers (both continuous 
and intermittent). By definition, a wellhead only well site would not 
have emissions associated with the major production and processing 
equipment, which includes storage vessels. Further, this proposed rule 
would not allow the use of natural gas-driven pneumatic controllers at 
any location (except on the Alaska North Slope), including wellhead 
only well sites. Therefore, the only emissions would be calculated 
based on the fugitive emissions components associated with the 
wellhead, which we believe would never be above 3 tpy.
    Proposed BSER for Sites with Baseline Emissions of 3 tpy or 
Greater. The EPA next evaluated what frequency of OGI monitoring is 
BSER for well sites where the total site-level baseline methane 
emissions are 3 tpy or greater. Table 14 summarizes the cost-
effectiveness information for each monitoring frequency evaluated at 
this threshold.

                   Table 14--Summary of Emission Reductions and Cost-Effectiveness for Site-Level Baseline Methane Emissions of 3 TPY
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                 Single-pollutant                 Multipollutant
                                                              Methane      VOC emission  ---------------------------------------------------------------
          Monitoring frequency              Annual cost      emission     reduction (tpy/  Methane cost-     VOC cost-     Methane cost-     VOC cost-
                                            ($/yr/site)      reduction         site)       effectiveness   effectiveness   effectiveness   effectiveness
                                                            (tpy/site)                        ($/ton)         ($/ton)         ($/ton)         ($/ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       3 tpy site-level baseline methaneemissions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Biennial................................          $2,500            0.90            0.25          $2,800         $10,000          $1,400          $5,000
Annual..................................           3,000            1.20            0.33           2,500           9,000           1,250           4,500
Semiannual..............................           3,200            1.80            0.50           1,800           6,400             900           3,200
Quarterly...............................           4,200            2.40            0.67           1,800           6,300             900           3,200
Monthly.................................           8,100            2.70            0.75           3,000          11,000           1,500           5,400
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 63192]]

    Based on the information summarized in Table 14, the average costs 
per ton reduced appear to be reasonable for either semiannual or 
quarterly monitoring when site-level baseline methane emissions are 3 
tpy or greater under the single pollutant approach for methane 
(biennial, annual, or monthly are outside of what the EPA considers 
reasonable for VOCs in the single pollutant approach), or reasonable at 
any frequency under the multipollutant approach.
    In addition to considering the average costs per ton reduced for 
these sites, the EPA also evaluated the incremental cost associated 
with progressing to greater monitoring frequencies. To conduct this 
analysis, the EPA first considered semiannual monitoring for these 
sites as a baseline for comparison. Since 2016, owners and operators 
have been conducting semiannual monitoring pursuant to NSPS OOOOa, 
State requirements, or voluntarily, thus demonstrating the 
reasonableness of that frequency. Additionally, the cost is comparable 
to the costs found reasonable in the 2016 NSPS OOOOa \238\ for both the 
single pollutant approach for methane or multipollutant approach for 
both methane and VOC. To determine if quarterly monitoring is 
reasonable for sites with total baseline methane emissions of 3 tpy, we 
evaluated the incremental costs of going from semiannual to quarterly 
monitoring. The incremental costs of semiannual to quarterly monitoring 
for an emissions baseline of 3 tpy methane is $1,700/ton methane and 
$6,000/ton VOC using the single pollutant approach (and $800/ton 
methane and $3,000/ton VOC using the multipollutant cost effectiveness 
approach). These incremental costs are within the range we find 
reasonable in this proposal under the single pollutant approach for 
methane and under the multipollutant approach.
---------------------------------------------------------------------------

    \238\ The 2020 Technical Rule amended only the VOC standards in 
the 2016 NSPS OOOOa and, as discussed in section X.A, incorrectly 
identified $738/ton as the highest value that the EPA found cost 
effective for methane reduction in the 2016 NSPS OOOOa.
---------------------------------------------------------------------------

    We next evaluated monthly monitoring for this cohort. As shown in 
Table 14, monthly monitoring appears reasonable under the 
multipollutant approach. Therefore, we evaluated the incremental costs 
of going from quarterly monitoring to monthly monitoring to determine 
if monthly monitoring is appropriate. Table 15 summarizes these 
incremental costs. As shown in Table 15, the incremental cost of going 
from quarterly to monthly monitoring when baseline emissions are 3 tpy 
is $13,000/ton methane and $47,000/ton VOC under the single pollutant 
approach ($6,500/ton methane and $23,500/ton VOC under the 
multipollutant approach). In both approaches, these costs are outside 
the range of what we are proposing to consider cost effective. See 
Section IX.B.
    Based on the analysis described above, we propose to find that 
quarterly monitoring at well sites with total site-level baseline 
methane emissions of 3 tpy or greater is the BSER. We note that 
California requires quarterly inspections for all well sites under its 
LDAR requirements in Code of Regulations, Title 17, Division 3, Chapter 
1, Subchapter 10 Climate Change, Article 4, Article Subarticle 13: 
Greenhouse Gas Emission Standards for Crude Oil and Natural Gas 
Facilities, which supports a conclusion that quarterly monitoring at 
these sites is feasible and cost-effective.\239\
---------------------------------------------------------------------------

    \239\ https://ww2.arb.ca.gov/sites/default/files/classic/regact/2016/oilandgas2016/ogfro.pdf.
---------------------------------------------------------------------------

    Accordingly, the EPA's primary proposal is to conclude that BSER 
for well sites with total site-level baseline emissions of less than 3 
tpy is no regular monitoring (but a one-time survey) and that BSER for 
well sites with total site-level baseline emissions of 3 tpy or greater 
is quarterly monitoring and repair.
    While the EPA is proposing quarterly OGI monitoring for well sites 
with total site-level baseline methane emissions of 3 tpy or greater, 
we are concerned this cost-effectiveness analysis may not fully account 
for the numerosity and diversity of sites and their potential emission 
profiles. We further note that some States with established fugitive 
emissions monitoring programs have provided for more graduated 
frequencies that recognize this diversity among sites. For example, 
Colorado's Regulation 7 Control of Ozone via Ozone Precursors and 
Control of Hydrocarbons via Oil and Gas Emissions \240\ requires a 
tiered inspection frequency regime that provides for semiannual 
monitoring at site-wide baseline emissions thresholds that far exceed 
the EPA's proposed 3 tpy threshold. Under the Colorado regulations, a 
semiannual inspection frequency is required for well production 
facilities with uncontrolled actual VOC emissions between 2 and 12 tpy 
(corresponding to approximately 7 to 43 tpy methane). Quarterly 
inspections are required for well sites without storage tanks and with 
uncontrolled actual VOC emissions between 12 and 20 tpy (corresponding 
to approximately 43 to 72 tpy methane), and for well sites with storage 
tanks and with uncontrolled actual VOC emissions between 12 and 50 tpy 
(corresponding to approximately 43 to 180 tpy methane). Colorado 
Regulation 7 also requires monthly inspections for well production 
facilities without storage tanks with uncontrolled actual VOC emissions 
above 20 tpy (and above 50 tpy for facilities with storage tanks). The 
proposed thresholds for quarterly monitoring in this action are more 
stringent than the Colorado regulations when compared using the gas 
composition ratio of 0.28 VOC to methane that is used in our BSER 
analysis. Specifically, the VOC emissions associated with a site-level 
baseline methane emission rate of 3 tpy are 0.83 tpy VOC, less than 
half the VOC threshold that requires semiannual monitoring and 14.5 
times lower than the VOC threshold requiring quarterly monitoring in 
Colorado.
---------------------------------------------------------------------------

    \240\ https://cdphe.colorado.gov/aqcc-regulations.
---------------------------------------------------------------------------

    Although Colorado's regulations are most directly comparable to the 
EPA's proposed approach, other States also provide for more graduated 
monitoring frequencies. For example, Ohio's General Permits 12.1 and 
12.2 initially require quarterly monitoring for well sites, followed by 
a reduced monitoring frequency of semiannual or annual monitoring 
depending on the fraction of equipment found to be leaking.\241\
---------------------------------------------------------------------------

    \241\ https://epa.ohio.gov/dapc/genpermit/oil-and-gas-well-site-production.
---------------------------------------------------------------------------

    When considering these State programs, particularly the comparison 
of our proposal to Colorado's thresholds; the fact that our cost-
effectiveness calculation may not account for the diversity of 
emissions and sites; and the concerns we have raised regarding the 
cost-effectiveness for businesses with fewer well sites than are 
assumed in our cost-effectiveness analysis (many of whom we anticipate 
are small businesses), the EPA believes it is also appropriate to co-
propose semiannual monitoring for well sites in a middle cohort--those 
with total site-level baseline emissions of 3 tpy or greater and less 
than 8 tpy. We seek comment on the number and ownership profile of 
wells that would fall into this category to better understand whether 
semiannual monitoring is an appropriate monitoring frequency for sites 
in this range.
    To inform this analysis, we evaluated methane emissions in 1 tpy 
increments starting at 3 tpy. Tables 15a and 15b summarize the total 
costs and incremental costs of semiannual to quarterly for baseline 
methane

[[Page 63193]]

emissions of 3 tpy or greater and less than 8 tpy.

              Table 15a--Summary of Total Cost-Effectiveness for Fugitive Monitoring at Well Sites
----------------------------------------------------------------------------------------------------------------
                                                      Single pollutant cost-           Multipollutant cost-
                                                           effectiveness                   effectiveness
   Site-level baseline methane    Annual cost ($/---------------------------------------------------------------
         emissions (tpy)             yr/site)       Methane ($/                     Methane ($/
                                                       ton)         VOC ($/ton)        ton)         VOC ($/ton)
----------------------------------------------------------------------------------------------------------------
                                              Semiannual Monitoring
----------------------------------------------------------------------------------------------------------------
3...............................          $3,200          $1,800          $6,400            $890          $3,200
4...............................           3,200           1,300           4,800             670           2,400
5...............................           3,200           1,100           3,800             530           1,900
6...............................           3,200             890           3,200             440           1,600
7...............................           3,200             760           2,700             380           1,400
8...............................           3,200             670           2,400             330           1,200
----------------------------------------------------------------------------------------------------------------
                                              Quarterly Monitoring
----------------------------------------------------------------------------------------------------------------
3...............................           4,200           1,800           6,300             880           3,200
4...............................           4,200           1,300           4,700             660           2,400
5...............................           4,200           1,000           3,800             530           1,900
6...............................           4,200             880           3,200             440           1,600
7...............................           4,200             750           2,700             380           1,400
8...............................           4,200             660           2,400             330           1,200
----------------------------------------------------------------------------------------------------------------


           Table 15B--Summary of Incremental Cost-Effectiveness for Fugitive Monitoring at Well Sites
----------------------------------------------------------------------------------------------------------------
                                                    Incremental                   Incremental cost-effectiveness
                                    Incremental       methane       Incremental  -------------------------------
   Site-level baseline methane    annual cost ($/    emission      VOC emission
         emissions (tpy)             yr/site)     reduction (tpy/ reduction (tpy/   Methane ($/     VOC ($/ton)
                                                       site)           site)           ton)
----------------------------------------------------------------------------------------------------------------
                                     Incremental for semiannual to quarterly
----------------------------------------------------------------------------------------------------------------
3...............................          $1,000            0.60            0.17          $1,700          $6,000
4...............................           1,000            0.80            0.22           1,250           4,500
5...............................           1,000            1.00            0.27           1,000           3,600
6...............................           1,000            1.20            0.33             840           3,000
7...............................           1,000            1.40            0.39             720           2,600
8...............................           1,000            1.60            0.45             630           2,250
----------------------------------------------------------------------------------------------------------------

    While there is no obvious cutoff point, the EPA anticipates that 
well sites with calculated baseline emissions of 8 tpy or greater will 
generally consist of complex sites comprising multiple wellheads and/or 
one or more of the major pieces of production or processing equipment 
that are known to have a propensity for causing large emissions events. 
The EPA also believes it is possible that at 8 tpy and greater, well 
sites are both more likely to be owned by companies with a larger 
number of sites and that the owners of these wells are likely to be 
larger companies. Lastly, the EPA estimates that a large share of 
fugitive emissions (approximately 54%) can be attributed to wells with 
site-wide baseline emissions of 8 tpy or greater.\242\ For these 
reasons, the EPA believes that an 8 tpy threshold for quarterly 
monitoring would appropriately focus resources on the wells with the 
largest emissions profiles, and that concerns about on the costs for 
small owners or operators are most attenuated for this cohort of 
relatively large and high-emitting sites. As noted above, we seek 
comment on whether it is sensible to have a middle cohort with a 
semiannual monitoring requirement and, if so, what the bounds of that 
cohort should be. In making this determination, the EPA is particularly 
interested in comments regarding the number and ownership profiles of 
well sites that may fall into this middle cohort.
---------------------------------------------------------------------------

    \242\ Percentage estimated using the analysis underpinning the 
baseline scenario in the RIA for the 2030 analysis year.
---------------------------------------------------------------------------

    As required by section 111, the EPA's proposed BSER analysis for 
fugitive emissions from all well sites has considered nonair quality 
health and environmental impacts. No secondary gaseous pollutant 
emissions or wastewater are generated during the monitoring and repair 
of fugitive emissions components. There are some emissions that would 
be generated by contractors conducting the OGI camera monitoring 
associated with driving to and from the site for the fugitive emissions 
survey. Using AP-42 mobile emission factors and assuming a distance of 
70 miles to the well site, the emissions generated from semiannual 
monitoring at a well site (140 miles to and from the well site twice a 
year) is estimated to be 0.35 lb/yr of hydrocarbons, 6.0 lb/yr of CO 
and 0.40 lb/yr of NOx. No other secondary impacts are 
expected. We do not believe these secondary emissions are so 
significant as to affect the proposed determinations described above.
    In summary, based on the analysis described above, the EPA is 
proposing OGI monitoring based on tiered total site-wide baseline 
methane emission levels to represent thresholds that would determine 
the monitoring frequency. For well sites with total site-level methane 
emissions less than 3 tpy,

[[Page 63194]]

the EPA is proposing to require a one-time survey to demonstrate that 
the well site is free of leaks or other abnormal conditions that are 
not accounted for in the baseline calculation. For well sites with 
total site-level methane emissions of 3 tpy or greater, the EPA is 
proposing quarterly monitoring at all sites. Lastly, the EPA is co-
proposing semiannual monitoring for well sites with total site-level 
methane emissions of 3 tpy or greater and less than 8 tpy, and 
quarterly monitoring for all sites with baseline emissions of 8 tpy or 
greater. As noted earlier, site-level baseline emission levels would be 
calculated by owners and operators for each site based on prescribed 
population emission factors for components and equipment at the site, 
combined with an assessment of potential methane emission from storage 
vessels (after applying controls).
b. Fugitive Emissions From Compressor Stations
    The EPA continues to utilize the model plant approach in estimating 
baseline fugitive emissions from compressor stations. Unlike well 
sites, we believe that compressor station designs are less variable and 
that model plants are an effective construct to analyze fugitive 
emission control programs. The EPA has evaluated feedback received from 
several industry stakeholders related to development of compressor 
station model plants over multiple years since the original 2015 NSPS 
OOOOa proposal were model plants for compressor stations (including 
those at gathering and boosting stations, transmission stations, and 
storage facilities) were first introduced. Consistent with this early 
approach for estimating emissions from compressor stations, the EPA 
still believes the model plant approach is the best way to assess 
fugitive emissions from compressor stations, in the absence of 
information indicating otherwise. Baseline model plant emissions for 
compressor stations can reasonably be calculated using equipment 
counts, fugitive emissions component counts, and emissions factors from 
the 1995 Emissions Protocol. The EPA has evaluated each specific model 
plant for gathering and boosting, transmission, and storage, based on 
information that has become available, and model plants were updated 
where information indicated an update was appropriate. For example, 
information from actual compressor stations in operation provided by 
GPA Midstream for several of their member companies representing 
numerous sites across the country, was used to refine the gathering and 
boosting model plant in 2020. Refinements have also been made to the 
transmission and storage model plants based on information received 
from companies in these segments. The size and equipment located at 
compressor stations do not vary as widely as at well sites, and 
therefore emissions are expected to be less variable as well. 
Furthermore, stakeholders have not indicated that a model plant 
approach is not reasonable. For these reasons, the EPA retains a model 
plant approach for compressor stations which are representative in 
estimating fugitive emissions.
    There are three types of compressor stations in the Crude Oil and 
Natural Gas source category: (1) Gathering and boosting stations, (2) 
transmission stations, and (3) storage stations. The equipment 
associated with these compressor stations vary depending on the volume 
of natural gas that is transported and whether any treatment of the gas 
occurs, such as the removal of water or hydrocarbons. The model plants 
developed for these sites include all equipment (including piping and 
associated components, compressors, generators, separators, storage 
vessels, and other equipment) and associated components (e.g., valves 
and connectors) that may be sources of fugitive emissions associated 
with these operations. One model plant was developed for each of the 
three types of compressor stations described above, which are discussed 
in detail in the 2020 NSPS OOOOa TSD and in the NSPS OOOOb and EG TSD 
supporting this action. For gathering and boosting stations, the 
fugitive baseline emissions were estimated to be 16.6 tpy of methane 
and 4.6 tpy of VOC. For transmission stations, the fugitive baseline 
emissions were estimated to be 40.4 tpy of methane and 1.1 tpy of VOC. 
For storage stations, the fugitive baseline emissions were estimated to 
be 142.2 tpy of methane and 3.9 tpy of VOC.
    As with well sites, in the original BSER analysis for the 2016 NSPS 
OOOOa rulemaking, two options for reducing fugitive methane and VOC 
emissions at compressor stations were identified, which were (1) a 
fugitive emissions monitoring program based on individual component 
monitoring using EPA Method 21 for detection combined with repairs and 
(2) a fugitive emissions monitoring program based on the use of OGI 
detection combined with repairs. Finding that both methods achieve 
comparable emission reduction but OGI was more cost effective, the EPA 
ultimately identified quarterly monitoring of compressor stations using 
OGI as the BSER. 81 FR 35862. While there are several new fugitive 
emissions technologies under development, the EPA needs additional 
information and better understanding of these technologies, and they 
are therefore not being evaluated as potential BSER at this time. For 
this analysis for both the NSPS and the EG, we re-evaluated OGI as 
BSER. In the discussion below, we evaluate OGI control options based on 
varying the frequency of conducting the survey and fugitive emissions 
repair threshold (i.e., the visible identification of methane or VOC 
when an OGI instrument is used). For this analysis, we considered 
annual, semiannual, quarterly, and monthly survey frequency for 
compressor stations.
    In 2015, we evaluated the potential emission reductions from the 
implementation of an OGI monitoring program where an emission reduction 
of 40, 60 and 80 percent for annual, semiannual, and quarterly 
monitoring survey frequencies, respectively, were determined 
appropriate. No other information reviewed since 2015 indicates that 
the assigned reduction frequencies are different than previously 
established and the reduction efficiencies are consistent with what 
current information indicates. In addition, we also evaluated monthly 
monitoring for compressor stations where information evaluated 
indicated monthly OGI monitoring has the potential of reducing 
emissions up towards 90 percent.
    We evaluated the costs of monitoring and repair under various 
monitoring frequencies described above, including the cost of OGI 
monitoring via the camera survey, repair costs, resurvey costs, 
monitoring plan development and the cost of a recordkeeping system. For 
compressor stations, the capital cost associated with the fugitives 
monitoring program were estimated to be $3,090 for each gathering and 
boosting compressor station, which includes development of a fugitive 
emissions monitoring plan for a company-defined area (assumed to 
include 7 gathering and boosting compressor stations) and database 
management development or licensing for recordkeeping. These capital 
costs are divided evenly amongst the 7 gathering and boosting 
compressor stations in the company-defined area for purposes of the 
model plant analysis, consistent with the 2016 NSPS OOOOa and 2020 
Technical Rule analyses. The capital cost associated with the fugitives 
monitoring program for transmission and storage compressor stations was 
estimated at $23,880, which is for a single transmission and storage 
compressor station. The annual costs

[[Page 63195]]

include the capital recovery cost (calculated at a 7 percent interest 
rate for 10 years), survey and repair costs, database management fees, 
and recordkeeping and reporting costs. The annual costs estimated for 
compressor stations range from $6,350 for annual monitoring to $33,220 
for monthly monitoring at gathering and boosting compressor stations. 
For transmission compressor stations, the annual costs estimated range 
from $12,900 for annual monitoring to $39,770 for monthly monitoring. 
For storage compressor stations, the annual costs estimated range from 
$17,000 for annual monitoring to $43,860 for monthly monitoring.
    As discussed above, the EPA is proposing that natural gas-driven 
intermittent vent controllers at production and natural gas 
transmission sites in Alaska without electricity would be subject to a 
standard that prohibits emissions when the controller is idle. 
Intermittent pneumatic controllers are designed to vent during 
actuation only, but these devices are known to malfunction and operate 
incorrectly which causes them to release natural gas to the atmosphere 
when idle. For sites in Alaska that do not have electricity located in 
the production segment (well sites, gathering and boosting stations, 
and centralized tank batteries) and in the transmission and storage 
segment, the EPA is proposing to define intermittent natural gas-driven 
pneumatic controllers as an affected facility and proposing to apply a 
standard that these controllers only vent during actuation and not when 
idle. See section XII.C on pneumatic controllers for a full explanation 
of this standard. We have determined that it would be efficient and 
reasonable to verify proper actuation and that venting does not occur 
during idle times by proposing that these devices are monitored along 
with fugitive emissions components at a site to ensure these devices 
are meeting the standard. We believe the cost of monitoring of 
intermittent pneumatic controllers will be absorbed by the cost of the 
fugitive emissions program, and that little to no additional cost would 
be associated with monitoring these devices on the fugitive emissions 
components monitoring schedule. If compressor stations have 
electricity, they would be required to have non-emitting controllers, 
and no additional costs are expected to be incurred relayed to repair 
and/or replacement of malfunctioning intermittent vent controllers.
    At gathering and boosting compressor stations there are savings 
associated with the gas not being released. The value of the natural 
gas saved is assumed to be $3.13 per Mcf of recovered gas. Transmission 
and storage compressor stations do not own the natural gas; therefore, 
revenues from reducing the amount of natural gas emitted/lost was not 
applied for this segment.
    The EPA evaluated the cost-effectiveness of monitoring for each 
sub-type of compressor station, starting with evaluating whether 
quarterly monitoring remains the BSER. The 2016 NSPS OOOOa requires a 
fugitive emissions monitoring and repair program, where compressor 
stations have to be monitored quarterly. Compressor stations have 
successfully met this standard. Further, several State agencies have 
rules that require quarterly monitoring at compressor stations. For 
example, Colorado's Regulation 7 Control of Ozone via Ozone Precursors 
and Control of Hydrocarbons via Oil and Gas Emissions \243\ requires a 
semiannual inspection frequency for compressor stations with 
uncontrolled actual VOC emissions between 2 and 12 tpy, a quarterly 
inspection frequency for compressor stations with uncontrolled actual 
VOC emissions between 12 and 50 tpy, and monthly inspections for 
compressor stations with uncontrolled actual VOC emissions above 50 
tpy. California requires quarterly inspections under their LDAR 
requirements \244\ and similarly, Ohio's General Permit 18.1 also 
requires quarterly monitoring for compressor stations.\245\ These 
examples of State rules, where quarterly monitoring appears to be the 
lowest monitoring frequency required with one exception where the VOC 
baseline emissions were extraordinarily high, is a demonstration of the 
reasonableness of monitoring fugitive emissions components on a 
quarterly basis for compressor stations.
---------------------------------------------------------------------------

    \243\ https://cdphe.colorado.gov/aqcc-regulations.
    \244\ https://ww2.arb.ca.gov/sites/default/files/classic/regact/2016/oilandgas2016/ogfro.pdf.
    \245\ https://www.epa.state.oh.us/dapc/genpermit/ngcs/GP_181.
---------------------------------------------------------------------------

    Given the apparent reasonableness of quarterly monitoring as 
discussed above, the EPA evaluated whether it was reasonable to require 
monthly monitoring for compressor stations. Table 16 summarizes the 
cost, emission reductions, and cost-effectiveness of quarterly and 
monthly OGI monitoring at compressor stations for the single pollutant 
approach, while Table 17 summarizes the multi-pollutant approach.

                     Table 16--Summary of the Single Pollutant Cost of Control for Compressor Station Fugitive Emissions Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Emission reductions        Methane cost     VOC cost of
                                           Capital cost   Annual cost ($/ Annual cost w/ -------------------------------- of control w/o    control w/o
               Model plant                      ($)             yr)       savings ($/yr)  Methane  (tons/                   savings ($/     savings ($/
                                                                                                yr)        VOC (tons/yr)       ton)            ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Quarterly Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gathering & Boosting....................          $3,100         $13,400         $11,000            13.3             3.7          $1,000          $3,600
Transmission............................          23,900          19,900          19,900            32.3             0.9             600          22,300
Storage.................................          23,900          24,000          24,000           114.0             3.2             200           7,600
                                         ---------------------------------------------------------------------------------------------------------------
    Compressor Program Weighted Average.  ..............  ..............  ..............  ..............  ..............             900           4,400
                                         ---------------------------------------------------------------------------------------------------------------
                                                                   Monthly Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gathering & Boosting....................           3,100          33,200          30,500            15.0             4.2           2,200           8,000
Transmission............................          23,900          39,800          39,800            36.4             1.0           1,100          39,500
Storage.................................          23,900          43,900          43,900           128.2             3.5             340          12,400
                                         ---------------------------------------------------------------------------------------------------------------
    Compressor Program Weighted Average.  ..............  ..............  ..............  ..............  ..............           1,800           9,300
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 63196]]


                      Table 17--Summary of the Multi-Pollutant Cost of Control for Compressor Station Fugitive Emissions Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                Emission reductions        Methane cost     VOC Cost of
                                           Capital cost   Annual cost ($/ Annual cost w/ -------------------------------- of control w/o    control w/o
               Model plant                      ($)             yr)       savings ($/yr)  Methane (tons/                    savings ($/     savings ($/
                                                                                                yr)        VOC (tons/yr)       ton)            ton)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                  Quarterly Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gathering & Boosting....................          $3,100         $13,400         $11,000            13.3             3.7            $500          $1,800
Transmission............................          23,900          19,900          19,900            32.3             0.9             300          11,100
Storage.................................          23,900          24,000          24,000           114.0             3.2             100           3,800
                                         ---------------------------------------------------------------------------------------------------------------
    Compressor Program Weighted Average.  ..............  ..............  ..............  ..............  ..............             430           2,200
                                         ---------------------------------------------------------------------------------------------------------------
                                                                   Monthly Monitoring
--------------------------------------------------------------------------------------------------------------------------------------------------------
Gathering & Boosting....................           3,100          33,200          30,500            15.0             4.2           1,100           4,000
Transmission............................          23,900          39,800          39,800            36.4             1.0             550          19,800
Storage.................................          23,900          43,900          43,900           128.2             3.5             200           6,200
                                         ---------------------------------------------------------------------------------------------------------------
    Compressor Program Weighted Average.  ..............  ..............  ..............  ..............  ..............             900           4,600
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Based on the single pollutant approach, both quarterly and monthly 
frequencies are reasonable for methane emissions, while only quarterly 
is reasonable for VOC emissions. Like described for well sites, owners 
and operators of compressor stations have been monitoring quarterly 
since 2016 pursuant to NSPS OOOOa, State requirements, or voluntarily, 
which suggests these costs are reasonable. These costs for quarterly 
monitoring are also comparable to those found reasonable in both the 
2016 NSPS OOOOa and the 2020 Technical Rule. Further, both frequencies 
are reasonable under the multipollutant approach when considering the 
total cost-effectiveness compared to a baseline of no OGI monitoring.
    The EPA then looked at the incremental costs of going from 
quarterly to monthly monitoring. Quarterly monitoring achieves an 
emission reduction ranging from 13.3 tpy at gathering and boosting 
compressor stations to 114 tpy at storage compressor stations. Monthly 
monitoring achieves additional reductions ranging from 1.7 tpy at 
gathering and boosting compressor stations to 14.2 tpy at storage 
compressor stations. However, these additional reductions are achieved 
at $9,400/ton methane (and nearly $50,000/ton VOC). The EPA finds that 
achieving these additional emissions reductions is not reasonable for 
the cost, given the only small fraction of additional reductions 
realized at monthly monitoring. Based on the cost analysis summarized 
above, we find that the cost effectiveness of quarterly monitoring for 
compressor stations is reasonable.
    Finally, no secondary gaseous pollutant emissions or wastewater are 
generated during the monitoring and repair of fugitive emissions 
components. There are some emissions that would be generated by the OGI 
camera monitoring contractors with respect to driving to and from the 
site for the fugitive emissions survey. Using AP-42 mobile emission 
factors and assuming a distance of 70 miles to the compressor station, 
the emissions generated from quarterly monitoring at a compressor 
station (140 miles to and from the compressor station four times a 
year) is estimated to be 0.70 lb/yr of hydrocarbons, 12.0 lb/yr of CO 
and 0.80 lb/yr of NOX. No other secondary impacts are 
expected.
    In light of the above, we find that the BSER for reducing methane 
and VOC emissions from all compressor stations, including gathering and 
boosting stations, transmission stations, and storage stations is 
quarterly monitoring for this proposal. Therefore, for NSPS OOOOb, we 
are proposing to require quarterly monitoring for all compressor 
stations.
2. EG OOOOc
    The EPA also evaluated BSER for the control of fugitive emissions 
at existing well sites and compressor stations. The findings were that 
the controls evaluated for new sources for NSPS OOOOb are appropriate 
for consideration under the EG OOOOc. Further, the EPA finds that the 
OGI monitoring, methane emission reductions, costs, and cost 
effectiveness results discussed above for new sources are also 
applicable for existing sources.
    Therefore, for the EG OOOOc, the EPA is proposing presumptive 
standards to require quarterly monitoring for well sites with site-
level baseline methane emissions greater than and equal to 3 tpy. 
Further, we are co-proposing semiannual monitoring for well sites with 
site-level baseline methane emissions greater than and equal to 3 tpy 
and less than 8 tpy, and quarterly monitoring for well sites with site-
level baseline methane emissions greater than and equal to 8 tpy. We 
find the costs reasonable for existing well sites with total site-level 
baseline methane emissions greater than or equal to 3 tpy to conduct 
quarterly OGI monitoring at an incremental cost of $1,700/ton methane 
reduced. We are aware that there is a large percentage of existing well 
sites that are likely owned and operated by small businesses. We 
continue to be concerned about the burden of frequent OGI monitoring on 
these small businesses and are requesting comment consistent with our 
solicitation for new sources.
    The EPA also finds, and is proposing, that the BSER for reducing 
methane emissions from all existing compressor stations, including 
gathering and boosting stations, transmission stations, and storage 
stations is quarterly monitoring. For compressor stations, we find that 
both quarterly (at $430/ton methane reduced) and monthly monitoring (at 
$900/ton methane reduced) are reasonable when looking at total cost-
effectiveness against a baseline of no monitoring, however, at an 
incremental cost of $9,400/ton methane reduced, monthly monitoring is 
not reasonable. Therefore, for the EG OOOOc, we are proposing a 
presumptive standard of quarterly monitoring for all compressor 
stations.

[[Page 63197]]

3. Alternative Screening Using Advanced Measurement Technology
    As discussed throughout this preamble, the EPA recognizes the 
existence large emission events. In certain instances, these situations 
could be caused by severely and continuously leaking components that 
would be identified and corrected via the routine OGI-based periodic 
monitoring program, but only on a quarterly or semiannual basis. 
Moreover, some large emission events are intermittent and stochastic in 
nature and may not be identified via these OGI surveys. Since the 2016 
NSPS OOOOa, significant strides have occurred in developing and 
deploying methane detection technologies that can detect fugitive 
emissions (especially large emission events) in a potentially faster 
and more cost-effective manner than traditional techniques such as OGI 
and EPA Method 21. The EPA has continued following the development of 
these technologies and their applications through various public 
programs, such as the DOE ARPA-E programs, which have focused on the 
development of cost-effective tools to locate and measure methane 
emissions. Additionally, the EPA has continued discussions with 
stakeholders, including academic researchers and private industry, as 
they develop and evaluate novel tools for the detection and 
quantification of methane emissions in the oil and gas sector. As noted 
in section VII.B, the EPA also held a two-day workshop in August 2021 
to hear perspectives on these new technologies. Some of the promising 
technologies now emerging include, but are not limited to, fixed-base 
and open path sensor networks, unmanned aircraft systems (UAS) equipped 
with methane detection equipment, the use of high-end instruments for 
mobile measurements on the ground and in the air, and satellite 
observations with advanced optical techniques.
    As the EPA learned during the Methane Detection Technology 
Workshop, industry has utilized these advanced measurement technologies 
to supplement existing fugitive emissions programs and to quickly 
identify unexpected emissions events (e.g., emissions from controlled 
storage vessels) in order to make repairs as quickly as possible.\246\ 
While most of these advanced measurement technologies are not sensitive 
enough to pin-point the exact same emission sources as the current 
fugitive emission detection programs, many can more quickly detect the 
largest emissions sources (e.g., malfunctions and undersized or non-
performing major equipment), and they can also find emissions that may 
be missed by fugitive emission surveys (e.g., component-level leaks on 
valves, connectors, and meters). Moreover, the EPA understands the 
stochastic nature, distribution, and frequency of these large emission 
events across sites and over time is uncertain, and that these events 
occur sporadically at an individual site in ways that may take longer 
to detect or might not be detected through a periodic fugitive 
emissions survey using traditional technologies. Integrating advanced 
emission detection technologies into this rule--whether deployed by 
owner-operators themselves or by third parties--could be a valuable way 
to reduce fugitive emissions more cost-effectively and rapidly detect 
and remedy ``super-emitting'' events that make an outsize contribution 
to overall emissions from this source category.
---------------------------------------------------------------------------

    \246\ See summary report of the EPA's Methane Detection Workshop 
located at Docket ID No. EPA-HQ-OAR-2021-0317.
---------------------------------------------------------------------------

    There are many other advantages to these advanced measurement 
technologies over technologies currently used for fugitive emissions 
detection (i.e., OGI and EPA Method 21 technologies). For instance, 
these advanced measurement technologies may be less susceptible to 
operator error or judgment than traditional methods of leak detection, 
thus making surveys more consistent and reliable. Many of these 
technologies can survey broader areas than can be effectively surveyed 
with field personnel, drastically reducing the driving time from site 
to site, which could have potential cost and safety benefits and allow 
for more frequent monitoring, which could allow for the identification 
and mitigation of large volume methane emissions sooner than OGI or EPA 
Method 21 surveys.
    As described in section XI.A.5, the EPA is proposing an alternative 
work practice for detecting fugitive emissions that incorporates these 
advanced measurement technologies. There were a number of presentations 
during the Methane Detection Technology Workshop that discussed the 
detection capabilities of various methane measurement technologies 
which could be used for a screening approach. Given the diverse array 
of advanced technologies that are now in use, and the rapid pace at 
which these technologies are being refined and new technologies are 
being developed, the EPA believes that it is appropriate to articulate 
a foundational set of performance criteria and documentation 
requirements for this alternative work practice that can be applied to 
multiple existing and forthcoming technologies. Based on the 
information available to the Agency, including the information 
presented in the Methane Detection Technology Workshop, the EPA 
believes setting a minimum detection threshold of 10 kg/hr methane 
might be appropriate for use in determining what technologies and in 
what deployment platforms (e.g., fixed, ground and aerial) are 
appropriate for a potential screening alternative within the proposed 
NSPS OOOOb and EG OOOOc. Therefore, the specific alternative work 
practice that the EPA is proposing includes a provision that would 
allow the use of any technology with a minimum detection threshold of 
10 kg/hr.
    Although we have focused this discussion on advanced measurement 
technologies, the EPA is also soliciting comment on whether there are 
ways to utilize existing technologies to screen for large emission 
events. For example, could gauges or meters be utilized to identify 
potential large losses between the wellhead and the custody meter 
assembly.
    Further, the EPA is seeking comment on very simple AVO checks that 
could be performed in conjunction with the periodic OGI monitoring 
surveys to help identify potential large emission events. For example, 
two often-cited causes of super-emitter sources are unlit flares and 
separator dump valves that are stuck open allowing unintentional gas 
carry-through to emit from storage vessels. The additional time and 
cost required to perform visual inspections to see if the flare pilot 
light is working, or to see if a dump valve is stuck open, would be 
minimal. Yet the benefits of simple AVO inspections could be 
significant. The EPA is soliciting comment on this concept, as well as 
comments on the common items that could be included on a checklist for 
such low-burden AVO inspections in conjunction with fugitive 
monitoring.

B. Proposed Standards for Storage Vessels

1. NSPS OOOOb
a. Background
    In the 2012 NSPS OOOO, the EPA established VOC standards for 
storage vessels. Based on our review of these standards, we are 
proposing to retain the current standard of 95 percent reduction. 
However, the EPA is proposing to redefine the affected facility to 
include a tank battery. Specifically, the EPA is proposing to define a 
storage vessel affected facility as a single storage vessel or a group 
of storage vessels that are physically adjacent and that receive fluids 
from the

[[Page 63198]]

same source (e.g., well, process unit, or set of wells or process 
units) or manifolded together for the transfer of liquid or vapors. In 
this definition, we consider tanks to be physically adjacent when they 
are near or next to each other and may or may not be connected or piped 
together. In addition, the EPA is proposing methane standards for new, 
reconstructed, and modified storage vessels under the proposed NSPS 
OOOOb. Both the proposed revised VOC standards and the proposed methane 
standards would be the same (i.e., 95 percent reduction of emissions 
from storage vessel affected facilities as defined above in this 
proposal). These reductions can be achieved by utilizing a cover and 
closed vent system to capture and route the emissions to a control 
device that achieves an emission reduction of 95 percent, or by routing 
the captured emissions to a process.
    Both methane and VOC emissions from storage vessels are a result of 
working, breathing and flashing losses. Working losses occur when 
vapors are displaced due to the emptying and filling of storage 
vessels. Breathing losses are the release of gas associated with daily 
temperature fluctuations when the liquid level remains unchanged. 
Flashing losses occur when a liquid with dissolved gases is transferred 
from a vessel with higher pressure (e.g., separator) to a vessel with 
lower pressure (e.g., storage vessel), thus allowing dissolved gases 
and a portion of the liquid to vaporize or flash. In the Crude Oil and 
Natural Gas source category, flashing losses occur when crude oils or 
condensates flow into a storage vessel from a separator operated at a 
higher pressure. Typically, the higher the operating pressure of the 
upstream separator, the greater the flash emissions from the storage 
vessel. Temperature of the liquid may also influence the amount of 
flash emissions. Lighter crude oils and condensate generally flash more 
hydrocarbons than heavier crude oils.
b. Definition of Affected Facility
    The current standards apply to single storage vessels with 
potential VOC emissions of 6 tpy or greater, although the EPA has long 
observed that these storage vessels are typically located as part of a 
tank battery. 76 FR 52738, 52763 (Aug. 23, 2011). Further, the 6 tpy 
applicability threshold was established by directly correlating VOC 
emissions to throughput, was based on the use of a single combustion 
control device, regardless of the number of storage vessels routing 
emissions to that control device, and control of 6 tpy VOC was cost 
effective using that single control device. Id. at 52763-64. Over the 
years, there have been questions and issues raised regarding how to 
calculate the potential VOC emissions from individual storage vessels 
that are part of a tank battery. The EPA attempted to address this 
issue through various amendments to NSPS OOOO and NSPS OOOOa,\247\ most 
recently in the 2020 Technical Rule. In the 2020 Technical Rule, the 
EPA continued to recognize that tank batteries are more prevalent than 
individual storage vessels. While the 2020 Technical Rule included 
amendments to the calculation methodology for determining potential VOC 
emissions from storage vessels that are part of a tank battery, the EPA 
has now determined that it is more appropriate to evaluate the control 
of methane and VOC emissions from tank batteries \248\ as a whole 
instead of each individual storage vessel within a tank battery.\249\ 
In this review the EPA evaluated regulatory options based on the use of 
a single control device to reduce both methane and VOC emissions from a 
tank battery, which is consistent with the 2012 NSPS OOOO, 2016 NSPS 
OOOOa, and subsequent amendments to each of those rules. The EPA 
believes that this approach will simplify applicability criteria for 
owners and operators of storage vessels, and more accurately aligns 
with the EPA's original intent of how storage vessel affected facility 
status should be determined.
---------------------------------------------------------------------------

    \247\ See 79 FR 79018 and 80 FR 48262.
    \248\ For purposes of this analysis and the resulting proposed 
standards, the term ``tank battery'' refers to a single storage 
vessel or a group of storage vessels that are physically adjacent 
and that receive fluids from the same source (e.g., well, process 
unit, or set of wells or process units) or which are manifolded 
together for liquid or vapor transfer.
    \249\ This approach would no longer allow facilities to apply 
certain criteria and average the total potential VOC emissions of 
the tank battery across the number of storage vessels in the battery 
to determine a per-vessel potential for VOC emissions.
---------------------------------------------------------------------------

c. Modification
    Section 60.14(a) of the general provisions to part 60 defines 
modification as follows: ``Except as provided in paragraphs (e) and (f) 
of this section, any physical or operational change to an existing 
facility which results in an increase in the emission rate to the 
atmosphere of any pollutant to which a standard applies shall be 
considered a modification. . . .'' We also note that 40 CFR 60.14(f) 
states that ``Applicable provisions set forth under an applicable 
subpart of this part shall supersede any conflicting provisions of this 
section.'' The EPA understands the difficulty assessing emissions from 
storage vessels and seeks to provide clarity on actions that are 
considered modification of a tank battery by explicitly listing these 
in the proposed NSPS OOOOb. We evaluated circumstances that would lead 
to an increase in the VOC and methane emissions from a tank battery and 
therefore constitute a modification of an existing tank battery. A 
modification of an existing tank battery would then require the tank 
battery owner or operator to assess the potential emissions relative to 
the proposed NSPS instead of the EG.
    The EPA is proposing that a single storage vessel or tank battery 
is modified when any of the following physical or operational changes 
are made: (1) The addition of a storage vessel to an existing tank 
battery; (2) replacement of a storage vessel such that the cumulative 
storage capacity of the existing tank battery increases; and/or (3) an 
existing single storage vessel or tank battery that receives additional 
crude oil, condensate, intermediate hydrocarbons, or produced water 
throughput (from actions such as refracturing a well or adding a new 
well that sends these liquids to the tank battery). For both items 1 
and 2, even if the type and quantity of fluid processed remains the 
same, the increased storage capacity will lead to higher breathing 
losses and thereby increase the VOC emissions from the tank battery 
relative to the VOC emissions prior to the vessel addition or 
replacement. Therefore, we conclude that these actions are a 
modification of the tank battery. However, we are soliciting comment to 
help us better understand the effect of the proposed definition number 
1 and 2 on the number of new storage vessels or tank batteries that 
would be subject to the NSPS. Under the current definition of a storage 
vessel affected facility in NSPS OOOOa, which is each single storage 
vessel that meets the 6 tpy applicability threshold, a new storage 
vessel that is installed in an existing tank battery is an affected 
facility (assuming the 6 tpy applicability threshold is met for the 
single storage vessel) whether the new storage vessel is a replacement 
or an addition to the tank battery. However, under the proposed 
definition number 1 and 2 above, the NSPS OOOOb is triggered only if 
the new storage vessel is an addition to the tank battery or is of 
bigger capacity than the storage vessel it is replacing in a tank 
battery. We therefore solicit comment on how often a storage vessel in 
a tank battery is replaced with one that is of bigger capacity, or 
whether the need to increase a tank battery's capacity is

[[Page 63199]]

generally accomplished by adding storage vessels as opposed to 
replacing an existing one with a bigger one. We further solicit comment 
on whether, under our proposed definition of a tank battery (i.e., a 
single storage vessel or a group of storage vessels that are physically 
adjacent and that receive fluids from the same source (e.g., well, 
process unit, or set of wells or process units)), the replacement of a 
storage vessel in a tank battery should also require the assessment of 
the potential VOC and methane emissions from the tank battery.
    Item 3 will increase the volumetric throughput of the tank battery 
relative to the throughput prior to storage of the additional fluid. 
This will increase the working losses and potentially increase the 
flashing losses from the tank battery, depending on the properties of 
the new fluid stream. In any event, adding a new fluid stream to an 
existing tank battery increases the VOC emissions from that tank 
battery relative to just prior to the addition of a new fluid stream 
and is therefore considered a modification of the tank battery.
    The EPA is proposing to require that the owner or operator 
recalculate the potential VOC emissions when any of these actions occur 
on an existing single storage vessel or tank battery to determine if 
the modification may require control of VOC emissions. The existing 
single storage vessel or tank battery will only become subject to the 
proposed NSPS if it is modified pursuant to this proposed definition of 
modification and its potential VOC emissions exceed the proposed 6 tpy 
VOC emissions threshold for the tank battery.
d. Technology Review
    The available control techniques for reducing methane and VOC 
emissions from storage vessels include routing the emissions from the 
storage vessels to a combustion control device or a VRU, which would 
route the emission to a process (including a gas sales line). These are 
the same control systems that were evaluated under the 2012 NSPS OOOO. 
While floating roofs can also be used to reduce emissions from many 
storage vessel applications, including at natural gas processing plants 
and compressor stations, floating roofs are not effective at reducing 
emissions from storage vessels that have flashing losses (e.g., storage 
vessels at well sites or centralized production facilities). Besides 
the control options described above, we did not find other available 
control options through our review, including review of the RACT/BACT/
LAER Clearinghouse.
    In the development of the 2012 NSPS OOOO, we found that using 
either a VRU or a combustion control device could achieve a 95 percent 
or higher VOC emission reduction efficiency. Available information 
since then continues to support that such devices can achieve a 95 
percent control efficiency for both methane and VOC emissions. We are 
not proposing to require higher control efficiency because, in order to 
achieve a minimum of 95 percent control efficiencies on a continuous 
basis, operators will need to design and operate the control to achieve 
greater than 95 percent. Thus, while the control device may commonly 
operate at greater than 95 percent control efficiencies, there may be 
process fluctuations in heat loads, inlet backpressure, and other 
variables that may affect performance that may lower the control 
efficiencies achieved. For example, there are field conditions, such as 
high winds that may influence combustion efficiencies.\250\ We also 
note that, while the EPA established operating and monitoring 
requirements to ensure flares achieve a 98 percent control efficiency 
at petroleum refineries in 40 CFR part 63, subpart CC, these 
requirements include sophisticated monitoring and operational controls 
and tend to lead to additional fuel use and greater secondary impacts 
than combustion systems targeting to achieve a minimum of 95 percent 
control efficiency. Considering these factors, we conclude that, 
consistent with CAA section 111(a) definition of a ``standard of 
performance,'' 95 percent control efficiency as the minimum allowable 
control efficiency at any time continues to reflect ``the degree of 
emission limitation achievable'' through the application of the BSER 
for tank batteries (a combustor or a VRU). We solicit comment on the 
issues described above for requiring higher than 95 percent 
reduction.\251\
---------------------------------------------------------------------------

    \250\ EPA. April 2012. Parameters for Properly Designed and 
Operated Flares. Prepared for U.S. Environmental Protection Agency, 
Office of Air Quality Planning and Standards, Research Triangle 
Park, NC.
    \251\ Further, in section XIII.E (solicitation of comment on 
control device efficiency), the EPA solicits comment on the level of 
reduction that can be reliably achieved using a flare and what 
measures need to be in place to assure such reduction.
---------------------------------------------------------------------------

    During pre-proposal outreach, some small businesses raised a 
concern that the NSPS OOOOa requirement for a continuous pilot light 
for a storage vessel control device generated more emissions than it 
prevented for storage vessels with low emissions. Specifically, small 
business representatives raised concerns that there are situations 
where propane or other fossil fuel must be used to maintain continuous 
pilot lights for flares used as control devices on storage vessels that 
do not produce enough emissions. The EPA is interested in whether the 
benefits of reducing emissions with these control devices are negated 
by the need to burn additional fossil fuels and whether there are 
additional factors that lead to variability in emissions from storage 
vessels that could be used to more narrowly target these requirements 
to limit the unnecessary operation of flares. We are soliciting comment 
from all stakeholders on this issue.
e. Control Options and BSER Analysis
    For this proposal, the EPA evaluated regulatory options based on 
different potential emissions thresholds for VOC and methane. We 
assumed the potential tank battery emissions were reduced by 95 percent 
using either a VRU or a combustion control device. Since VRUs recover 
saleable products, we also estimated the value of the recovered product 
when VRUs were used. The EPA encourages the use of VRUs to capture and 
sell the emissions from the storage vessels by classifying VRUs as part 
of the process, therefore emission recovered would not be included in 
the potential emissions at a site.
    For new, modified, or reconstructed sources, we evaluated the cost 
of control using a single combustion device (or VRU) on a single 
storage vessel as well as a tank battery made up of multiple storage 
vessels. To do this, we evaluated the use of a single control device 
achieving 95 percent reduction of VOC and methane emissions at the 
following potential emission thresholds: 6 tpy VOC from a single 
storage vessel; 3 and 6 tpy VOC from a tank battery; and 1.3 tpy, 5.3 
tpy, 20 tpy, and 50 tpy methane from a tank battery. Based on our cost 
analysis we propose to retain the 6 tpy applicability threshold.
    The estimated all-in capital costs for a single combustion control 
device are approximately $80,000. The estimated annualized costs 
include the capital recovery cost (calculated at a 7 percent interest 
rate for 15 years) and labor costs for operations and maintenance and 
are estimated at approximately $31,500/yr. The estimated capital costs 
for a VRU sized for a source with potential VOC emissions of 6 tpy are 
approximately $32,000 and the estimated annualized costs are estimated 
at approximately $24,000/yr not considering any potential recovery 
credits from sales. More information on this cost analysis

[[Page 63200]]

is available in the NSPS OOOOb and EG TSD for this proposal.
    Based on our analysis, the cost effectiveness of controlling VOC 
and methane emissions from a tank battery with the potential for VOC 
emissions of 6 tpy, under the single pollutant approach where all the 
costs are assigned to the reduction of VOC, is $5,540 per ton of VOC 
eliminated assuming the use a single combustion control device. As 
explained above, storage vessels are commonly located adjacent to one 
another as part of tank battery, which allows the vapors from the 
storage vessels within the tank battery to be collected and routed to a 
single control device, when one is used. The single pollutant cost 
effectiveness for a VRU to control a tank battery with potential VOC 
emissions of 6 tpy is approximately $4,000 per ton of VOC eliminated. 
As shown in section IX, costs ranging from $4,000 to $5,540 per ton of 
VOC reduced are within the range that the EPA considers to be cost 
effective for reducing VOC emissions. Because it is cost effective to 
reduce the VOC emissions from a tank battery with potential VOC 
emissions of 6 tpy or greater, one of the two targeted pollutants in 
this action, it is cost effective to reduce both VOC and methane 
emissions from a single storage vessel or a tank battery at that level. 
Based on our estimate, a tank battery with potential 6 tpy VOC 
emissions has potential 1.3 tpy of methane emissions. Because storage 
vessels contain crude oil, condensate, intermediate hydrocarbons, or 
produced water, which are approximately 80 percent VOC, the methane 
emissions from storage vessels are generally less than the VOC 
emissions.
    We also evaluated the cost effectiveness at a lower VOC threshold 
of 3 tpy. As shown in the NSPS OOOOb and EG TSD, the single pollutant 
cost effectiveness for controlling a tank battery with potential 
emissions of 3 tpy ranges from $7,500 to $11,000. As shown in section 
IX, costs ranging from $7,500 to $11,000 per ton of VOC reduced is not 
within the range that the EPA considers to be cost effective for 
reducing VOC emissions. Using the multipollutant approach, the VOC cost 
effectiveness is between $3,800 and $5,500, which is considered 
reasonable, but the methane cost effectiveness is between $17,000 and 
$25,000 for any of the methane thresholds assessed in conjunction with 
3 tpy VOC limit, which is considered unreasonable. Therefore, the 3 tpy 
VOC control option was not considered reasonable at this time using 
either the single pollutant or multipollutant approach.
    Our analysis also shows that, under the single pollutant approach 
where all the costs are assigned to the reduction of methane and zero 
to VOC, it is cost effective to control a single storage vessel or a 
tank battery with potential methane emissions of 20 tpy (at costs 
ranging from $1,250 to $1,660 per ton methane). Based on our estimate, 
a tank battery with potential methane emissions of 20 tpy would have 
the potential VOC emissions of 91 tpy, 95 percent of which would be 
reduced at zero cost. Under the multipollutant cost-effectiveness 
approach, where half of the cost is allocated to methane reduction and 
the other half to VOC reduction, it is cost effective to control a tank 
battery with potential methane emissions of 10 tpy and corresponding 
potential VOC emissions of 46 tpy, at an average cost of $1,500 per ton 
methane reduced and $330 per ton VOC reduced. In light of the above, 6 
tpy of VOC is the lowest threshold that is cost effective to control 
both VOC and methane emissions. Therefore, the EPA is proposing to 
define the affected facility for purposes of regulating both VOC and 
methane emissions as a tank battery with potential VOC emissions of 6 
tpy or greater.
2. EG OOOOc
    The EPA is proposing presumptive standards for reducing methane 
emissions from existing storage vessels. For purposes of the EG, we are 
proposing to define a designated facility as a single storage vessel or 
tank battery with the potential for methane emissions of 20 tpy or 
greater. For purposes of the EG, we are proposing the same definition 
of a storage vessel affected facility, which is a single storage vessel 
or a group of storage vessels that are physically adjacent and that 
receive fluids from the same source (e.g., well, process unit, or set 
of wells or process units).
    The available controls for reducing methane emissions from existing 
tank batteries are the same as those for reducing methane and VOC 
emissions from new, modified and reconstructed tank batteries. In 
assessing the control costs for existing sources, we applied a 30 
percent retrofit factor to the capital and installation costs to 
account for added costs of manifolding existing storage vessels and 
installing the control system on an existing tank battery. When 
applying controls to new sources, there is limited additional costs in 
designing the fixed roof with fittings to manifold the vapors and 
installing the closed vent piping or ducts during the tank installation 
process. For existing sources, installing fittings on an existing tank 
may require special lifts to access the roof and cut new ports in the 
roof. This may also require the tank to be taken out of service to 
conduct these installations, which requires additional time and labor. 
Additionally, when installing controls as part of the design for a new 
source, the facility layout can be designed to accommodate the control 
systems near the tank battery and the control device can be installed 
with the same crew installing the storage vessels, minimizing 
additional installation costs. For existing sources, there may be other 
equipment near the tanks that may require the control equipment to be 
further from the tank battery, which increases materials and 
installation costs. Also, control equipment costs will include the full 
costs of crew mobilization. Therefore, it is more expensive to install 
controls at an existing tank battery than to install controls as part 
of a new tank battery. We considered the same regulatory options based 
on potential methane emissions thresholds of 1.3 tpy, 5.3 tpy, 20 tpy, 
and 50 tpy per tank battery.
    The estimated capital costs for a single combustion control device 
for emissions in this range are approximately $103,000. The estimated 
annual costs include the capital recovery cost (calculated at a 7 
percent interest rate for 15 years) and labor costs for operations and 
maintenance and are estimated at approximately $34,000. The costs for 
VRU are more variable than combustion control systems and dependent on 
the potential emissions for which the VRU is designed to recover. The 
estimated capital costs for a VRU sized for a source with potential 
methane emissions of 20 tpy device are approximately $106,000 and the 
estimated annualized costs are approximately $49,000/yr not considering 
any potential recovery credits. With a VRU, the recovered VOC and 
methane are recovered as salable products. Considering the value of 
recovered product, the annualized cost for VRU sized to recover 
potential methane emissions of 20 tpy is estimated to be $26,000/yr. 
More information on this cost analysis is available in the NSPS OOOOb 
and EG TSD for this proposal.
    The resulting cost effectiveness, for the application of a single 
combustion control device or VRU to achieve a 95 percent emission 
reduction ranges from $19,000 to $27,400 per ton of methane eliminated 
at a threshold of 1.3 tpy methane. This cost is not considered 
reasonable. Next, we evaluated the cost effectiveness at a methane 
threshold of 5.3 tpy, which ranged from $10,000 to $13,700 per ton of 
methane reduced,

[[Page 63201]]

which is also not considered reasonable. At a threshold of 20 tpy 
methane, the cost effectiveness ranges from $1,400 to $1,800 per ton 
methane reduced. At a threshold of 50 tpy methane, the cost 
effectiveness ranges from $340 to $720 per ton methane reduced. When we 
considered the application of these options at a national level, the 
overall cost effectiveness of the 20 tpy potential methane emissions 
threshold was $400 per ton methane reduced without considering product 
recovery credits and has a net cost savings considering product 
recovery credits. Additionally, the incremental cost effectiveness of 
the 20 tpy option relative to the 50 tpy potential methane emissions 
threshold was approximately $900 per ton additional methane reduced 
when considering product recovery credits.
    Based on the cost analysis summarized above, we find that the cost 
effectiveness for achieving 95 percent emission reduction of methane 
from a tank battery with potential methane emissions of 20 tpy is 
reasonable for methane. A cost-effective value of $1,800/ton of methane 
reduction is comparable to the estimated methane cost-effectiveness 
values for the controls identified as BSER for the 2016 NSPS OOOOa and 
which we consider to be representative of reasonable control cost for 
reducing methane emissions from the Crude Oil and Natural Gas source 
category, as explained in section IX.B. We further note that both 
California and Colorado require 95 percent reduction of methane 
(California) and hydrocarbon (Colorado) emissions from storage vessels. 
For California, existing separator and tank systems with an annual 
emission rate greater than 10 tpy methane must control emissions using 
a vapor collection system that reduces emissions by at least 95 
percent.\252\ For Colorado, storage vessels that emit greater than or 
equal to 2 tpy of actual uncontrolled VOC emissions must reduce VOC 
emissions by 95 percent.\253\ These requirements, which are comparable 
to the proposed presumptive standards, are further indication that the 
cost of implementing the proposal is reasonable and not excessive.
---------------------------------------------------------------------------

    \252\ See sections 95668 and 95671 of California Code of 
Regulations, Title 17, Division 3, Chapter 1, Subchapter 10 Climate 
Change, Article 4.
    \253\ See section I.D.3.a of Colorado Department of Public 
Health and Environment, ``Control of Ozone via Ozone Precursors and 
Control of Hydrocarbons via Oil and Gas Emissions (Emissions of 
Volatile Organic Compounds and Nitrogen Oxides), Regulation Number 
7'' (5 CCR 1001-9), July 2021.
---------------------------------------------------------------------------

3. Legally and Practicably Enforceable Limits
    In addition to the BSER analysis described above, the EPA is 
clarifying the term ``legally and practicably enforceable limits'' as 
it related to storage vessel affected facilities in the proposed NSPS 
OOOOb and EG OOOOc. In the 2016 NSPS OOOOa, the EPA stated that ``any 
owner or operator claiming technical infeasibility, nonapplicability, 
or exemption from the regulation has the burden to demonstrate the 
claim is reasonable based on the relevant information. In any 
subsequent review of a technical infeasibility or nonapplicability 
determination, or a claimed exemption, the EPA will independently 
assess the basis for the claim to ensure flaring is limited and 
emissions are minimized, in compliance with the rule.'' See 81 FR 
35824, 35844 (June 3, 2016).
    In the context of storage vessels under both the 2012 NSPS OOOO and 
2016 NSPS OOOOa, the EPA has learned that numerous owners and operators 
claim that their storage vessels are not affected facilities under 40 
CFR 60.5365(e) and 40 CFR 60.5365a(e). This claim is made based on a 
determination that the potential for VOC emissions is less than 6 tpy 
when taking into account requirements under a legally and practicably 
enforceable limit in an operating permit or other requirement 
established under a Federal, State, local or Tribal authority.\254\ 
However, when the EPA has reviewed the limits considered by these 
facilities as legally and practicably enforceable, we have become aware 
that the limits do not require a reduction in emissions; they are often 
self-imposed or of such a general nature as to be unenforceable or 
otherwise lack measures to assure the required emission reduction. For 
example, a permit contains an emission limit of 2 tpy for a single 
storage vessel, but does not contain any performance testing 
requirements, continuous or other monitoring requirements, 
recordkeeping and reporting, or other requirements that would ensure 
that emissions are maintained below the emissions limit in the permit. 
In National Mining Ass'n v. EPA, 59 F.3d 1351 (D.C. Cir. 1995), the 
court explained what constitutes ``effective'' control in assessing a 
source's potential to emit. According to the court, while ``effective'' 
controls need not be Federally enforceable, ``EPA is clearly not 
obliged to take into account controls that are only chimeras and do not 
really restrain an operator from emitting pollution.'' Id. at 1362. The 
court also emphasized that these non-Federally enforceable controls 
must stem from state or local government regulations, and not 
``operational restrictions that an owner might voluntarily adopt.'' Id. 
at 1362. Further, as a general ``default rule,'' the burden of proof 
falls ``upon the party seeking relief.'' Schaffer ex rel. Schaffer v. 
Weast, 546 U.S. 49, 57-58, 126 S.Ct. 528, 163 L.Ed.2d 387 (2005).
---------------------------------------------------------------------------

    \254\ 40 CFR 60.5365(e) and 40 CFR 60.5365a(e)(1) and (2) allow 
owners and operators to take into account these requirements when 
calculating the potential VOC emissions.
---------------------------------------------------------------------------

    In light of the above, the EPA is proposing to include a definition 
for a ``legally and practicably enforceable limit'' as it relates to 
limits used by owners and operators to determine the potential for VOC 
emissions from storage vessels that would otherwise be affected 
facilities under these rules. The intent of this proposed definition is 
to provide clarity to owners and operators claiming the storage vessel 
is not an affected facility in the Oil and Gas NSPS due to legally and 
practicably enforceable limits that limit their potential VOC emissions 
below 6 tpy. This definition is being proposed for NSPS OOOOb and the 
proposed presumptive standard included in EG OOOOc. This proposed 
definition of ``legally and practicably enforceable limit'' is 
consistent with the EPA's historic position on what is considered 
``legally and practicably enforceable,'' as tailored to storage vessels 
in the oil and gas sector that would otherwise be affected facilities 
under these rules. The proposed definition is as follows:
    ``For purposes of determining whether a single storage vessel or 
tank battery is an affected facility, a legally and practicably 
enforceable limit must include all of the following elements:
    i. A quantitative production limit and quantitative operational 
limit(s) for the equipment, or quantitative operational limits for the 
equipment;
    ii. an averaging time period for the production limit in (i) (if a 
production-based limit is used) that is equal to or less than 30 days;
    iii. established parametric limits for the production and/or 
operational limit(s) in (i), and where a control device is used to 
achieve an operational limit, an initial compliance demonstration 
(i.e., performance test) for the control device that establishes the 
parametric limits;
    iv. ongoing monitoring of the parametric limits in (iii) that 
demonstrates continuous compliance with the production and/or 
operational limit(s) in (i);
    v. recordkeeping by the owner or operator that demonstrates 
continuous

[[Page 63202]]

compliance with the limit(s) in (i-iv); and
    vi. periodic reporting that demonstrates continuous compliance.''
    In this proposed definition, the EPA is not addressing the various 
ways in which a State or other authority's permit may be issued since 
the format of permit issuances varies by jurisdiction. The proposed 
definition of ``legally and practicably enforceable'' does not specify 
limits, monitoring requirements, or recordkeeping. Instead, the owner 
or operator should work with the permitting authority to establish 
specific limits, monitoring requirements and recordkeeping that will 
ensure any permitted emission limit is achieved. Only those limits that 
include the elements described above will be considered ``legally and 
practicably enforceable'' for purposes of determining the potential for 
VOC emissions from a single storage vessel or tank battery, and thus 
applicability (or non-applicability) of each single storage vessel or 
tank battery as an affected facility under the rule.
    This proposed definition will provide clarity to owners and 
operators in what limits are necessary to ensure they have 
appropriately determined their single storage vessels or tank batteries 
are affected facilities under the proposed NSPS OOOOb or designated 
facilities under the proposed EG OOOOc. Further, as stated in the 2016 
NSPS OOOOa, well-designed rules ensure fairness among industry 
competitors and are essential to the success of future enforcement 
efforts. 81 FR 35844 (June 3, 2016). The EPA is soliciting comment on 
this proposed definition from all stakeholders.

C. Proposed Standards for Pneumatic Controllers

1. NSPS OOOOb
a. Background
    In the 2012 NSPS OOOO, the EPA established VOC standards for 
natural gas-driven pneumatic controllers. Specifically, subpart OOOO 
established a natural gas bleed rate limit of 6 scfh for individual, 
continuous bleed, natural gas-driven controllers located in the 
production segment. Continuous bleed, natural gas-driven controllers 
with a bleed rate of 6 scfh or less are commonly called ``low bleed'' 
controllers. However, that rule also allowed for the use of ``high 
bleed'' controllers (those with a bleed rate over 6 scfh) where 
required by functional needs such as response time, safety, and 
positive actuation. At natural gas processing plants, subpart OOOO 
implemented a VOC standard that required a bleed rate of zero (``zero 
bleed'' or ``no bleed''). The rule also included allowances for the use 
of continuous bleed natural gas-driven controllers at natural gas 
processing plants where required by functional needs.
    In the 2016 NSPS OOOOa, the EPA extended the 6 scfh natural gas 
bleed rate standard to the natural gas transmission and storage segment 
and established GHG standards for all segments. Effectively, the 2016 
NSPS OOOOa required low bleed controllers to reduce methane and VOC 
emissions from the production and transmission and storage segments and 
required a bleed rate of zero for pneumatic controllers at natural gas 
processing plants. Like the 2012 NSPS OOOO, the 2016 NSPS OOOOa 
included allowances for the use of continuous high bleed controllers in 
the production and transmission and storage segments and continuous 
natural gas-driven pneumatic controllers at natural gas processing 
plants where required by functional needs.
    Emissions from natural gas-driven intermittent vent pneumatic 
controllers were not addressed in either the 2012 NSPS OOOO or the 2016 
NSPS OOOOa. This was because, when operated and maintained properly, 
methane and VOC emissions from intermittent controllers are 
substantially lower (by an order of magnitude) than emissions from 
other types of natural gas-driven controllers. However, the EPA is now 
aware that these intermittent controllers often malfunction and vent 
during idle periods. Emissions factors considering this fact are around 
four times higher than the factors for low-bleed controllers. Further, 
as presented in subsection c of this section, methane emissions from 
intermittent controllers make up a significant portion of the overall 
methane emissions from all natural gas and petroleum system sources in 
the GHGI. As such, the EPA is now proposing to reduce emissions from 
intermittent controllers via NSPS OOOOb.
b. Affected Facility Definitions and Zero Emissions Standard
    As a result of the review of these requirements in the 2016 NSPS 
OOOOa, the previous BSER determinations, and the consideration of new 
information, including State regulations that have been enacted since 
2016, the EPA is proposing GHG (methane) and VOC standards for natural 
gas-driven pneumatic controllers in all segments of the industry 
included in the Crude Oil and Natural Gas source category (i.e., 
production, processing, transmission and storage).
    First, in terms of the definition of an affected facility, the EPA 
is proposing to revise the types of pneumatic controllers that are 
affected facilities to include both continuous bleed controllers and 
intermittent vent controllers. For continuous bleed controllers, an 
affected facility is each single continuous bleed natural gas-driven 
pneumatic controller that vents to the atmosphere. For intermittent 
vent controllers, an affected facility is each single natural gas-
driven pneumatic controller that is not designed to have a continuous 
bleed rate but is designed to only release natural gas to the 
atmosphere as part of the actuation cycle. These affected facility 
definitions apply for pneumatic controllers in both the production and 
transmission and storage segments, as well as for those at natural gas 
processing plants.
    Next, in terms of standards, we are proposing a requirement that 
all controllers (continuous bleed and intermittent vent) in the 
production and natural gas transmission and storage segments must have 
a methane and VOC emission rate of zero. Controllers that emit zero 
methane and VOC to the atmosphere can include, but are not limited to, 
air-driven pneumatic controllers (also referred to as instrument air-
driven or compressed air-driven controllers), mechanical controllers, 
electronic controllers, and self-contained natural gas-driven pneumatic 
controllers. While these ``zero-emissions controllers'' would not 
technically be affected facilities because they are not driven by 
natural gas (air-driven, mechanical, and electronic) or because they do 
not vent to the atmosphere, owners and operators should maintain 
documentation if they would like to be able to demonstrate to permit 
writers or enforcement officials that there are no methane or VOC 
emissions from the controllers and that these controllers are not 
affected facilities and are not subject to the rule. The proposed 
standard would apply to both continuous bleed and intermittent vent 
controllers at these sites.
    For all natural gas processing plants, we are proposing to 
essentially retain the 2016 NSPS OOOOa standard that requires that 
controllers must have a methane and VOC emission rate of zero (i.e., 
zero-emissions controllers must be used). However, we are proposing to 
slightly change the wording of the standard from subparts OOOO and 
OOOOa, which require a ``bleed rate of zero.'' Many natural gas 
processing plants use pneumatic controllers that are powered by 
compressed air, which

[[Page 63203]]

can technically have a compressed air bleed rate greater than zero. Put 
another way, some controllers that are powered with compressed air can 
allow some of that compressed air to leave the controller and thus be 
released into the atmosphere (they can ``bleed'' compressed air). 
However, since the compressed air does not contain any natural gas, 
methane, or VOC, we are clarifying the standard by proposing to require 
that pneumatic controllers at natural gas processing plants have a 
methane and VOC emission rate of zero.
    In both NSPS OOOO and OOOOa, there is an exemption from the 
standards in cases where the use of a pneumatic controller affected 
facility with a bleed rate greater than the applicable standard is 
required based on functional needs, including but not limited to 
response time, safety, and positive actuation. The EPA is not 
maintaining this exemption in the proposed NSPS OOOOb, except for in 
very limited circumstances explained below. As discussed below, the 
reasons to allow for an exemption based on functional need in NSPS OOOO 
and OOOOa were based on the inability of a low-bleed controller to meet 
the functional requirements of an owner/operator such that a high-bleed 
controller would be required in certain instances. Since we are now 
proposing that pneumatic controllers have a methane and VOC emission 
rate of zero, we do not believe that the reasons related to the use of 
low bleed controllers are still applicable.
    The proposed rule also does include an exemption from the zero-
emission requirement for pneumatic controllers in Alaska at locations 
where electricity power is not available. In these situations, the 
proposed standards would require the use of a low-bleed controller 
instead of high-bleed controller. The proposed rule also includes the 
exemption for pneumatic controllers in Alaska at sites without power 
that would allow the use of high-bleed controllers instead of low-bleed 
based on functional needs. In addition, inspections of intermittent 
vent controllers to ensure they are not venting during idle periods 
described above would also be required at sites in Alaska without 
power.
c. Description
    Pneumatic controllers are devices used to regulate a variety of 
physical parameters, or process variables, using air or gas pressure to 
control the operation of mechanical devices, such as valves. The 
valves, in turn, control process conditions such as levels, 
temperatures and pressures. When a pneumatic controller identifies the 
need to alter a process condition, it will open or close a control 
valve. In many situations across all segments of the Oil and Natural 
Gas Industry, pneumatic controllers make use of the available high-
pressure natural gas to operate or control the valve. In these 
``natural gas-driven'' pneumatic controllers, natural gas may be 
released with every valve movement (intermittent) and/or continuously 
from the valve control. Pneumatic controllers can be categorized based 
on the emissions pattern of the controller. Some controllers are 
designed to have the supply-gas provide the required pressure to power 
the end-device, and the excess amount of gas is emitted. The emissions 
of this excess gas are referred to as ``bleed,'' and this bleed occurs 
continuously. Controllers that operate in this manner are referred to 
as ``continuous bleed'' pneumatic controllers. These controllers can be 
further categorized based on the rate of bleed they are designed to 
have. Those that have a bleed rate of less than or equal to 6 scfh are 
referred to as ``low bleed,'' and those with a bleed rate of greater 
than 6 scfh are referred to as ``high bleed.'' Another type of 
controller is designed to release gas only when the process parameter 
needs to be adjusted by opening or closing the valve, and there is no 
vent or bleed of gas to the atmosphere when the valve is stationary. 
These types of controllers are referred to as ``intermittent vent'' 
pneumatic controllers. A third type of natural gas-driven controller 
releases gas to a downstream pipeline instead of the atmosphere. These 
``self-contained'' types of controllers can be used in applications 
with very low pressure.
    As discussed above, emissions from natural gas-powered pneumatic 
controllers occur as a function of their design. Self-contained 
controllers do not emit natural gas to the atmosphere. Continuous bleed 
controllers using natural gas as the power source emit a portion of 
that gas at a constant rate. Intermittent vent controllers using 
natural gas as the power source are designed to emit natural gas only 
when the controller sends a signal to open or close the valve, which is 
called actuation. From continuous bleed and intermittent vent 
controllers, another source of emissions is from improper operation or 
equipment malfunctions. In some instances, a low bleed controller may 
emit natural gas at a higher level than it is designed to do (i.e., 
over 6 scfh) or an intermittent vent controller could emit continuously 
or near continuously rather than only during actuation.
    Not all pneumatic controllers are driven by natural gas. At sites 
with power, electrically powered pneumatic devices or pneumatic 
controllers using compressed air can be used. As these devices are not 
driven by pressurized natural gas, they do not emit any natural gas to 
the atmosphere, and consequently, they do not emit VOC or methane to 
the atmosphere. In addition, some controllers operate mechanically 
without a power source or operate electronically rather than 
pneumatically. At sites without electricity provided through the grid 
or on-site electricity generation, mechanical controllers and 
electronic controllers using solar power can be used.
    The emissions from natural gas-powered pneumatic controllers 
represent a significant portion of the total emissions from the Oil and 
Natural Gas Industry. In the 2021 GHGI, the estimated methane emissions 
for 2019 from pneumatic controllers were 700,000 metric tons of methane 
for petroleum systems and 1.4 million metric tons for natural gas 
systems. These levels represent 45 percent of the total methane 
emissions estimated from all petroleum systems (i.e., exploration 
through refining) sources and 22 percent of all methane emissions from 
natural gas systems (i.e., exploration through distribution). The vast 
majority of these emissions are from natural gas-driven intermittent 
vent controllers, which the EPA is proposing to define as an affected 
facility for the first time in NSPS OOOOb. Of the combined methane 
emissions from pneumatic controllers in the petroleum systems and 
natural gas systems production segments, emissions from intermittent 
vent controllers make up 88 percent of the total. Continuous high bleed 
and low bleed controllers make up 8 and 4 percent, respectively.
d. Control Options
    In identifying control options for this NSPS OOOOb proposal, we re-
examined the options previously evaluated in the rulemakings to 
promulgate the 2012 NSPS OOOO and the 2016 NSPS OOOOa, and also 
examined State rules with requirements for pneumatic controllers that 
achieve emission reductions beyond those achieved by NSPS OOOOa. For 
NSPS subparts OOOO and OOOOa, we identified options for reducing 
emissions from continuous bleed natural gas-driven pneumatic 
controllers. These options included using low bleed controllers in 
place of

[[Page 63204]]

high bleed controllers, enhanced maintenance (i.e., periodic inspection 
and repair), and using zero-emissions controllers. For the production 
and transmission and storage segments, only the option to require low 
bleed controllers was fully analyzed in these previous analyses. Based 
on the EPA's determination at that time that electricity was ``likely 
unavailable'' at production and transmission and storage sites, the EPA 
did not fully consider instrument air or electronic controllers. The 
EPA also did not evaluate enhanced maintenance, as it was concluded 
that the highly variable nature of determining the proper methods of 
maintaining a controller could incur significant costs. The EPA did not 
evaluate options to reduce emissions from intermittent vent controllers 
in either the 2012 or 2016 NSPS.
    Three U.S. States (California, Colorado, and New Mexico) and two 
Canadian provinces (Alberta and British Columbia) have rules or 
proposed rules that achieve emission reductions beyond those achieved 
by NSPS OOOOa. Starting on January 1, 2019, and subject to certain 
exceptions, a California rule requires that all new and existing 
continuous bleed devices must not vent natural gas to the atmosphere. 
The rule allows low bleed devices installed prior to January 1, 2016, 
to continue to operate, provided that annual testing is performed to 
verify that the low bleed rate is maintained. A Colorado rule adopted 
in February 2021, requires that all new controllers are no-bleed 
controllers (which includes self-contained natural gas-driven 
controllers), and over a period of two years, a sizeable portion of 
existing controllers must be retrofit to have a natural gas bleed rate 
of zero. New Mexico has proposed a rule that would require an emission 
rate of zero from all controllers located at sites with access to 
electrical power. The Canadian provinces of Alberta (effective 2022) 
and British Columbia (effective 2021) also regulate emissions from 
pneumatic controllers. In British Columbia, pneumatic devices that emit 
natural gas must not be used at new sources and at existing gas 
processing plants and large compressor stations, and in Alberta, owners 
and operators must prevent or control (by 95 percent) vent gas from new 
pneumatic controllers. While the terminology differs across these 
regulations, the EPA believes that all these requirements (with the 
exception of the 95 percent reduction requirement in Alberta) are very 
similar to if not the same as the zero methane and VOC emission 
requirement being proposed by the EPA for NSPS OOOOb.
    From EPA's review of our past BSER analysis as well as reviewing 
these other rules, several options were identified for the BSER 
analysis for NSPS OOOOb to reduce methane and/or VOC emissions from 
natural gas-driven pneumatic controllers. These include the following: 
(1) Use of low bleed natural gas-driven pneumatic controllers in the 
place of high bleed natural gas-driven pneumatic controllers; (2) 
require zero emissions from intermittent vent controllers except during 
actuation, and (3) prohibit the emissions of methane and VOC from all 
pneumatic controllers (i.e., establish a zero methane and VOC emission 
standard for both continuous bleed and intermittent bleed controllers).
e. 2021 BSER Analysis
Production and Transmission and Storage Segments
    For production and transmission and storage sites, the EPA 
evaluated two options. The first was an option to require the use of 
low bleed natural gas-driven pneumatic controllers in the place of high 
bleed natural gas-driven pneumatic controllers, along with a 
requirement that natural gas-driven intermittent vent pneumatic 
controllers only discharge natural gas during actuation. We also 
evaluated an option of establishing a zero methane and VOC emissions 
standard, which we propose to determine represents the BSER for 
production and natural gas transmission and storage sites.
    The first option evaluated was the use of low bleed natural gas-
driven pneumatic controllers in the place of high bleed natural gas-
driven pneumatic controllers. In the analysis of this option, we 
examined the emissions reduction potential, the cost of implementation, 
and the cost effectiveness in terms of cost per ton of emissions 
eliminated.
    The emission reduction potential of using a low bleed controller in 
place of a high bleed controller depends on the actual bleed rate of 
each device, which varies from device to device. Using average emission 
factors for each device type, the difference in emissions can be 
estimated on a per-controller basis. We estimated this difference 
between a low bleed and a high bleed device to be an 84 percent 
reduction for controllers in the production segment and a 92 percent 
reduction in emissions in the transmission and storage segment, 
equating to a difference of 2.1 tpy methane and 0.6 tpy VOC per 
controller in the production segment and 2.9 tpy methane and 0.08 tpy 
VOC per controller in the transmission and storage segment. The cost of 
a new low bleed natural gas-driven pneumatic controller is 
approximately $255 higher than the cost of a new high bleed device. On 
an annualized basis, assuming a 15-year equipment lifetime and a 7 
percent interest rate, the cost is $28 per year per low bleed 
controller. Under the single pollutant approach where all the costs are 
assigned to the reduction of one pollutant, the estimated cost 
effectiveness is $13 per ton of methane avoided and $48 per ton of VOC 
avoided per controller in the production segment. Using the 
multipollutant approach where half the cost of control is assigned to 
the methane reduction and half to the VOC reduction, the estimated cost 
effectiveness is $7 per ton of methane avoided and $24 per ton of VOC 
avoided. When considering the cost of saving the natural gas that would 
otherwise be emitted for the production segment, the cost effectiveness 
shows an overall savings under both the single pollutant and 
multipollutant approaches. For the natural gas transmission and storage 
segment, the cost effectiveness is $10 per ton methane avoided and $355 
per ton VOC avoided per controller using the single pollutant method, 
and $5 per ton of methane and $178 per ton of VOC avoided per 
controller using the multipollutant method. Transmission and storage 
facilities do not own the natural gas; therefore, revenues from 
reducing the amount of natural gas emitted/lost was not applied for 
this segment. These values are well within the range of what the EPA 
considers to be reasonable for methane and VOC using both the single 
pollutant and multipollutant approaches.
    We also evaluated a requirement that natural gas-driven 
intermittent vent pneumatic controllers only discharge natural gas 
during actuations. This emissions reduction option would be required in 
conjunction with a requirement to use low bleed controllers in place of 
high bleed controllers. The average emission factor determined by an 
industry study for natural gas-driven intermittent vent controllers, 
including both properly and improperly operating controllers, is 9.2 
scfh natural gas.\255\ Comparing this to the emission factor for a 
properly operating intermittent vent controller of 0.3 scfh natural gas 
illustrates the significant potential for reductions from a program 
that

[[Page 63205]]

identifies intermittent vent controllers that are improperly operating 
and repairing, replacing, or altering their operating conditions so 
they may function properly. To ensure these devices are emitting 
natural gas only during actuations in accordance with their design, 
there would be no equipment expenditure or associated capital costs; 
however, emissions monitoring or inspections, combined with repair as 
needed, would be necessary to ensure this proper operation is achieved. 
We considered requiring independent inspections specifically for 
intermittent vent controllers but concluded that it would be more 
efficient to couple inspections of these controllers with the 
inspections of equipment for leaks under the fugitive monitoring 
program (see section XII.A of this preamble).
---------------------------------------------------------------------------

    \255\ API Field Measurement Study: ``Pneumatic Controllers EPA 
Stakeholder Workshop on Oil and Gas.'' November 7, 2019--Pittsburgh 
PA. Paul Tupper.
---------------------------------------------------------------------------

    The second option we evaluated was a zero methane and VOC emissions 
standard. While applicability of both the 2012 NSPS OOOO and the 2016 
NSPS OOOOa are based on an individual pneumatic controller (as is the 
proposed definition of affected facility under NSPS OOOOb), zero-
emissions controller options are more appropriately evaluated as 
``site-wide'' controls. While individual natural gas-driven pneumatic 
controllers can be switched to other types of natural-gas driven 
pneumatic controllers (e.g., high bleed to low bleed types or low bleed 
to self-contained), the implementation of some zero-emissions 
controllers options would require equipment that would presumably be 
used for all the controllers at the site. For example, in order to 
utilize instrument air driven controllers, a compressor and related 
equipment would need to be installed. For the vast majority of 
situations, the EPA does not believe that an owner and operator would 
install a compressor just for a single controller, but rather would 
instead install a site-wide system to provide compressed air to all the 
controllers at the site. Therefore, to adequately account for the costs 
of the system, including the controllers and the common equipment, we 
evaluated these zero-emissions controller options using ``model'' 
plants.
    These model plants include assumptions regarding the number of each 
type of pneumatic controller at a site. Emissions were estimated for 
each of the model plants using a calculation based on of the number of 
controllers at the plant and emission factors for each controller. 
Three sizes of model plants (i.e., small, medium, and large) were 
developed and used for both the production and transmission and storage 
segments. Each model plant contained one high bleed natural gas-driven 
controller and increasing numbers of low bleed and intermittent natural 
gas-driven controllers. For the production segment, the controller-
specific emission factors used are from a recent study conducted by the 
American Petroleum Institute,\256\ and are 2.6 scfh, 16.4 scfh, and 9.2 
scfh total natural gas emissions for low bleed, high bleed, and 
intermittent bleed controllers, respectively. This API study did not 
cover the transmission and storage segment; therefore, the emission 
factors from GHGRP subpart W were used, which are 1.37 scfh, 18.2 scfh, 
and 2.35 scfh for low bleed, high bleed, and intermittent bleed 
controllers, respectively. It was assumed that the portion of natural 
gas that is methane is 82.9 percent in the production segment and 92.8 
percent in the transmission and storage segment. Further, it was 
assumed that VOCs were present in natural gas at a certain level 
compared to methane. The specific ratios assumed were 0.278 pounds VOC 
per pound methane in the production segment and 0.0277 pounds VOC per 
pound methane in the transmission and storage segment. This information 
results in estimated emissions for a single natural gas-driven 
pneumatic controller in the production segment of 0.39, 2.48, and 1.39 
tpy methane and 0.1, 0.7, and 0.4 tpy VOC per low bleed, high bleed, 
and intermittent vent controller, respectively. The emissions for a 
single natural gas-driven pneumatic controller in the transmission and 
storage segment are 0.23, 3.08, and 0.40 tpy methane and 0.006, 0.08, 
and 0.01 tpy VOC per low bleed, high bleed, and intermittent vent 
controller, respectively.
---------------------------------------------------------------------------

    \256\ API Field Measurement Study: ``Pneumatic Controllers EPA 
Stakeholder Workshop on Oil and Gas.'' November 7, 2019--Pittsburgh 
PA. Paul Tupper.
---------------------------------------------------------------------------

    Based on the factors described above and the number of each type of 
controller in each model plant, baseline emissions for the model plants 
were calculated. For the production model plants, the baseline 
emissions were calculated to be 5.7 tpy methane and 1.6 tpy VOC for the 
small model plant (assumes fewer controllers on site than medium 
plant), 11.2 tpy methane and 3.1 tpy VOC for the medium model plant 
(assumes more controllers on site than small plant), and 24.9 tpy 
methane and 6.9 tpy VOC for the large model plant (assumes more 
controllers on site than the medium plant). For the transmission and 
storage model plants, the baseline emissions were calculated to be 4.1 
tpy methane and 0.1 tpy VOC for the small model plant, 5.7 tpy methane 
and 0.2 tpy VOC for the medium model plant, and 10.0 tpy methane and 
0.3 tpy VOC for the large model plant. For detailed information on the 
configuration of these model plants and the calculation of the baseline 
emissions, see the NSPS OOOOb and EG TSD for this rulemaking, which is 
available in the docket.
    Instrument air controllers and electronic controllers were the two 
zero emission options evaluated. Both these options require electricity 
to operate. Instrument air systems use compressed air as the signaling 
medium for pneumatic controllers and pneumatic actuators, whereas 
electronic controllers send an electric signal to an electric actuator 
(rather than sending a pneumatic signal to a pneumatic actuator). As 
instrument air systems are usually installed at facilities where there 
is a high concentration of pneumatic control valves, electrical power 
from the grid, and the presence of an operator that can ensure the 
system is properly functioning, we evaluated the use of instrument air 
for the large model plant with more controllers and the use of 
electronic controllers, which can be powered by solar panels, at the 
small and medium-sized model plant with less controllers. The emission 
reduction potential of using these zero-emissions controllers rather 
than natural-gas-driven pneumatic controllers is 100 percent since 
these systems eliminate all natural gas emissions (they do not emit any 
VOC or methane). Based on the information available to the EPA during 
development of this proposal, these two zero-emissions options were the 
only two analyzed. The EPA solicits comment on the other potential 
zero-emission options for these sites (mechanical-only controllers, 
self-contained natural gas-driven controllers, and natural gas-driven 
controllers where the emissions are captured and routed to a process).
    For the small and medium-sized model plants, the zero-emissions 
option evaluated was the use of electronic controllers. The respective 
emissions reduction for small and medium-sized plants would be 5.7 and 
11.2 tpy methane and 1.6 and 3.1 tpy VOC in the production segment and 
4.1 and 5.7 tpy methane and 0.11 and 0.16 tpy VOC in the transmission 
and storage segment. The cost of a new electronic controller system 
using electricity from the grid or other on-site power generation is 
estimated to be $26,000 and $46,000, for small and medium-sized plants 
respectively. The cost of a new solar-powered electronic controller 
system is

[[Page 63206]]

estimated to be $28,000 and $52,000, for small and medium-sized plants 
respectively. The estimated annualized capital costs, assuming a 15-
year equipment lifetime and a 7 percent interest rate, are $2,800 and 
$5,040, respectively for a system powered with electricity from the 
grid or other power source for small and medium-sized plants, and 
$3,090 and $5,630, respectively, for a solar-powered system for small 
and medium-sized plants.
    For the production segment, considering the slightly more expensive 
solar-powered system, under the single pollutant approach, the 
estimated cost effectiveness is $550 per ton of methane avoided and 
$1,970 per ton of VOC avoided for a small plant and $500 per ton of 
methane avoided and $1,810 per ton of VOC avoided for a medium-sized 
plant. Using the multipollutant approach where half the cost of control 
is assigned to the methane reduction and half to the VOC reduction, the 
estimated cost effectiveness is $275 per ton of methane avoided and 
$980 per ton of VOC avoided for a small plant and $250 per ton of 
methane avoided and $900 per ton of VOC avoided for a medium-sized 
plant in the production segment. When considering the cost of saving 
the natural gas that would otherwise be emitted for the production 
segment, the cost effectiveness is $370 per ton of methane avoided and 
$1,320 per ton of VOC avoided for a small plant and $320 per ton of 
methane avoided and $1,150 per ton of VOC avoided for a medium-sized 
plant. Using the multipollutant approach, the estimated cost 
effectiveness is $185 per ton of methane avoided and $660 per ton of 
VOC avoided for a small plant and $160 per ton of methane avoided and 
$580 per ton of VOC avoided for a medium-sized plant in the production 
segment. These values are well within the range of what the EPA 
considers to be reasonable for methane and VOC using both the single 
pollutant and multipollutant approaches.
    For the natural gas transmission and storage segment, considering 
the slightly more expensive solar-powered system, the estimated cost 
effectiveness is $750 per ton of methane avoided and $27,200 per ton of 
VOC avoided for a small plant and $990 per ton of methane avoided and 
$35,700 per ton of VOC avoided for a medium-sized plant. Using the 
multipollutant approach, the estimated cost effectiveness is $380 per 
ton of methane avoided and $13,600 per ton of VOC avoided for a small 
plant and $490 per ton of methane avoided and $17,800 per ton of VOC 
avoided for a medium-sized plant. Transmission and storage facilities 
do not own the natural gas; therefore, revenues from reducing the 
amount of natural gas emitted/lost was not applied for this segment. 
While the cost effectiveness values for VOC are higher than the range 
of what the EPA considers to be reasonable for VOC, the cost 
effectiveness for methane is within the range of what the EPA considers 
to be reasonable for methane using the single pollutant approach.
    For the large model plants, the zero-emissions option evaluated was 
the use of instrument air systems. For the production segment, the 
emissions avoided would be 24.9 tpy methane and 6.9 tpy VOC, and in the 
transmission and storage segment 10.0 tpy methane and 0.3 tpy VOC. The 
cost of a new instrument air system is estimated to be $96,000 and the 
estimated annualized capital costs, assuming a 15-year equipment 
lifetime and a 7 percent interest rate, are $10,500. For the production 
segment, under the single pollutant approach, the estimated cost 
effectiveness is $420 per ton of methane avoided and $1,520 per ton of 
VOC avoided. Using the multipollutant approach, the estimated cost 
effectiveness is $210 per ton of methane avoided and $760 per ton of 
VOC avoided. When considering the cost of saving the natural gas that 
would otherwise be emitted for the production segment, the cost 
effectiveness is $240 per ton of methane avoided and $860 per ton of 
VOC avoided. Using the multipollutant approach, the estimated cost 
effectiveness is $120 per ton of methane avoided and $430 per ton of 
VOC avoided in the production segment. These values are well within the 
range of what the EPA considers to be reasonable for methane and VOC 
using both the single pollutant and multipollutant approaches.
    For the natural gas transmission and storage segment, the estimated 
cost effectiveness is $1,050 per ton of methane avoided and $38,000 per 
ton of VOC avoided. Using the multipollutant approach, the estimated 
cost effectiveness is $530 per ton of methane avoided and $19,000 per 
ton of VOC avoided. Transmission and storage facilities do not own the 
natural gas; therefore, revenues from reducing the amount of natural 
gas emitted/lost was not applied for this segment. While the cost 
effectiveness values for VOC are higher than the range of what the EPA 
considers to be reasonable for VOC, the cost effectiveness for methane 
is within the range of what the EPA considers to be reasonable for 
methane using the single pollutant approach.
    Note that the annual costs for these zero-emissions controllers are 
based on the annualized capital costs only. While we assume the 
maintenance costs for electric controllers is less than the costs for 
natural gas-driven controllers, there are costs associated with the use 
of electricity that are not incurred for natural gas-driven 
controllers. We solicit comments on whether such operational costs 
should be included in these estimates, as well as information regarding 
these costs.
    The capital costs of solar-powered controllers include the cost of 
the batteries, which represents around 7 percent of the total cost of a 
solar-powered system. As noted above, the capital cost was annualized 
assuming a 15-year lifetime, however batteries for a solar system may 
have a shorter life. We are soliciting comment on the life of these 
batteries and, if this life is shorter than 15 years, how the costs of 
these batteries should be included as a maintenance cost for solar 
powered systems.
    The EPA finds that the cost effectiveness for both the low bleed 
and zero-emissions options are reasonable for sites in the production 
and natural gas transmission and storage segments. The incremental cost 
effectiveness in going from the low bleed option to the zero-emissions 
option is estimated to be $390 and $340 per ton of additional methane 
eliminated for small and medium-sized plants ($1,400 and $1,200 per ton 
of VOC), respectively, in the production segment and $640 and $870 per 
ton of additional methane eliminated for small and medium-sized plants 
($23,000 and $31,500 per ton of VOC), respectively, in the transmission 
and storage segment. The incremental cost effectiveness in going from 
the low bleed option to the non-emissions option is estimated to be 
$260 and $940 per ton of additional methane and VOC avoided, 
respectively, for large plants in the production segment and to be $940 
and $34,000 per ton of additional methane and VOC avoided, 
respectively, for large plants in the transmission and storage segment. 
These incremental costs of control do not consider savings for the 
production segment. The EPA believes the incremental costs of control 
are reasonable for methane and VOC in the production segment, and for 
methane in the transmission and storage segment.
    As discussed above, several States and Canadian provinces require 
the use of controllers that do not emit methane or VOC throughout the 
Oil and Natural Gas Industry, which further demonstrates the 
reasonableness of this option and that there are no technical barriers 
inhibiting the use of electronic controllers or instrument air systems 
at sites in the production and transmission

[[Page 63207]]

and storage segments. In 2015, the EPA concluded that, ``[a]t sites 
without available electrical service sufficient to power an instrument 
air compressor, only gas driven pneumatic devices are technically 
feasible in all situations.'' (80 FR 56623, September 18, 2015). 
However, since that time, at least two States and two Canadian 
provinces have adopted regulations that require zero emitting 
controllers at all new sites. The EPA evaluated these rules, and 
considers these rules, along with the basic understanding that sources 
in these areas are able to comply with the rules, evidence that the 
feasibility issues that led to the EPA's previous decision not to 
require zero emission controllers in 2015 have been overcome. Further, 
the EPA recognizes that industry commenters on the proposed Colorado 
rule raised some of the same technical feasibility issues that have 
been presented to the EPA in the past, including battery storage 
capacity issues, weather-related issues, and mechanical issues related 
to vibration.\257\ However, despite these issues being raised, Colorado 
finalized the requirement that new controllers have a natural gas bleed 
rate of zero at all sites, even though without power. The EPA has 
considered new information since 2016 and has now concluded that use of 
zero-emission controllers is technically feasible subject to a 
particular proposed exception discussed below. The EPA specifically 
requests comments on this conclusion. The EPA further solicits comment 
on market availability of zero-emission options.
---------------------------------------------------------------------------

    \257\ Pneumatic Controller Task Force Report to the Air Quality 
Control Commission. Pneumatic Controller Field Study and 
Recommendations. Colorado Department of Public Health and 
Environment. Air Pollution Control Division. June 1, 2020.
---------------------------------------------------------------------------

    Secondary impacts from the use of electronic controllers and 
instrument air systems are indirect, variable, and dependent on the 
electrical supply used to power the compressor or controllers. These 
impacts are expected to be minimal. For example, it is estimated that 
the electricity needed to operate a compressor is only around 0.4 kW/
hour/controller when the compressor is operating. No other secondary 
impacts are expected. The EPA solicits comment on whether owners and 
operators would use diesel generators to generate power to run zero-
emissions controllers. The EPA recognizes that diesel generators would 
generate formaldehyde emissions and there could be associated secondary 
impacts. The EPA does not intend for diesel generators to be used.
    In light of the above, we find that the BSER for reducing methane 
and VOC emissions from natural gas-driven pneumatic controllers at 
production and transmission and storage sites is the use of zero-
emissions controllers. Therefore, for NSPS OOOOb, we are proposing to 
require zero emissions of methane and VOC to the atmosphere for all 
pneumatic controllers at production and transmission and storage sites.
    Both NSPS OOOO and NSPS OOOOa allow the use of high-bleed pneumatic 
controllers at production sites and natural gas-driven continuous bleed 
controllers at natural gas processing plants if it is determined that 
the use of such a pneumatic controller affected facility with a bleed 
rate greater than the applicable standard is required ``based on 
functional needs, including but not limited to response time, safety 
and positive actuation.'' See 40 CFR 60.5390(a) and 60.5390a(a). This 
exemption was based on comments received on the 2011 proposed NSPS OOOO 
rule. There, ``[t]he commenters suggest exemptions that address 
situations such as those where the natural gas includes impurities that 
could increase the likelihood of fouling a low-bleed pneumatic 
controller, such as paraffin or salts; where weather conditions could 
degrade pneumatic controller performance; during emergency conditions; 
where flow is not sufficient for low-bleed pneumatic controllers; where 
electricity is not available; and where engineering judgment recommends 
their use to maintain safety, reliability or efficiency.'' (77 FR 
49520, August 16, 2012). These reasons to allow for an exemption based 
on functional need were based on the inability of a low-bleed 
controller to meet the functional requirements of an owner/operator 
such that a high-bleed controller would be required in certain 
instances. Since we are now proposing that nearly all pneumatic 
controllers have a methane and VOC emission rate of zero, subject to 
exemption explained below, we do not believe that the reasons cited 
above are still applicable. Therefore, the proposed rule does not 
include an exemption based on functional need. The EPA is requesting 
comment regarding the possibility of situations where functional 
requirements/needs dictate that a natural gas-driven controller that 
emits any amount of VOC and/or methane be used. For example, are there 
situations where a zero-emission controller cannot be used due to 
functional needs such that an owner/operator must use a low-bleed 
controller or an intermittent controller instead? Comments requesting 
such an exemption should include details of the specific functional 
need and why all zero-emission controller options are not suitable.
    For many sites, the EPA believes that the most feasible zero-
emission option will be solar-powered controllers. The EPA recognizes 
that solar-powered controllers are dependent on sunshine, and in areas 
at higher latitudes that undergo prolonged periods without sunshine, 
this option could be problematic to implement due to the technical 
limitations of solar panels coupled with the practical realities 
related to the hours of sunshine received. Therefore, the proposed rule 
includes an exemption from the zero-emission requirement for pneumatic 
controllers at sites in Alaska that do not have access to power (i.e., 
electricity from the grid or produced using natural gas on-site). Sites 
with power have clearly demonstrated that zero emissions from 
controllers is achievable, and therefore the EPA is not proposing to 
exempt pneumatic controllers at sites in Alaska that have power. The 
proposed exemption would only apply to pneumatic controllers at sites 
located in Alaska that do not have access to power. In those 
situations, affected facilities would not be required to comply with 
the zero-emission standard, but instead must use low-bleed pneumatic 
controllers (unless a high bleed device is needed for functional 
reasons) and must monitor any intermittent controllers in conjunction 
with the fugitives monitoring program to ensure they are not venting 
when idle. The EPA is soliciting comment on this proposed exemption. 
Specifically, the EPA is interested in comments regarding the technical 
feasibility of solar panels to power pneumatic controllers in Alaska. 
The EPA is also interested in comments regarding whether there are 
other locations outside of Alaska where such an exemption may be 
warranted. In submitting responses to this request, commenters should 
be mindful that two Canadian Provinces, which are north of any U.S. 
State other than Alaska, require zero-emitting controllers at all new 
sites.
Natural Gas Processing Plants
    Natural gas processing plants typically have higher numbers of 
pneumatic controllers than production and transmission and storage 
sites. Model plants were also used for this analysis, specifically the 
model plants used are the same as those used for the 2011 and 2015 BSER 
analyses, and include small, medium, and large sites.

[[Page 63208]]

The number of controllers is 15, 63, and 175 for small, medium, and 
large model plants, respectively. All controllers at these sites are 
assumed to be continuous, but the number of low bleed and high bleed 
devices is not specified for the model plants. It was assumed that each 
controller emitted 1 tpy methane, as derived from Volume 12 of a 1996 
GRI report.\258\ In addition, it was assumed that the portion of 
natural gas that is methane is 82.8 percent in the natural gas 
processing segment, and the specific VOC to methane ratio assumed was 
0.278 pounds VOC per pound methane. For detailed information on the 
configuration of these model plants, see the NSPS OOOOb and EG TSD, 
which is available in the docket.
---------------------------------------------------------------------------

    \258\ Radian International LLC. Methane Emissions from the 
Natural Gas Industry, Vol. 12: Pneumatic Devices. Prepared for the 
Gas Research Institute and Environmental Protection Agency. EPA-600/
R-96-080k. June 1996.
---------------------------------------------------------------------------

    For natural gas processing plants, the only option evaluated was 
the requirement to use zero-emission controllers. For our analysis, we 
examined the use of instrument air, which is the most commonly used 
controller technology at natural gas processing plants. For this 
analysis, we used cost data from the 2011 NSPS OOOO TSD updated to 2019 
dollars. The updated capital costs for an instrument air system at a 
natural gas processing plant ranges from $20,000 to $162,000, depending 
on the system size. The annualized costs were based on a 7 percent 
interest rate and a 10-year equipment life. This equated to an 
annualized cost of approximately $13,000 to $96,000 per system. The 
emissions reduction associated with the installation of an instrument 
air system over natural gas-driven pneumatic controllers ranged from 
approximately 15 to 175 tpy methane and 4.2 to 49 tpy VOC per system. 
The cost effectiveness is estimated to range from approximately $550 to 
$900 per ton methane eliminated $2,000 to $3,100 per ton VOC 
eliminated. When considering the costs of saving the natural gas that 
would otherwise be emitted, the cost effectiveness improves, with a 
cost effectiveness of $370 to $700 per ton of methane eliminated and 
$1,300 to $2,500 per ton of VOC eliminated. These cost effectiveness 
values are presented on a single pollutant basis, and the cost of 
control on a multipollutant basis is 50 percent of these values. These 
values are well within the range of what the EPA considers to be 
reasonable for methane and VOC using both the single pollutant and 
multipollutant approaches.
    The 2012 NSPS OOOO and 2016 NSPS OOOOa require a zero-bleed 
emission rate for pneumatic controllers at natural gas processing 
plants. Natural gas processing plants have successfully met this 
standard for many years now. Further, several State agencies have rules 
that include this zero-bleed requirement for controllers at natural gas 
processing plants. This is further demonstration of the reasonableness 
of a zero methane and VOC emission standard for pneumatic controllers 
at natural gas processing plants.
    We find the cost effectiveness of eliminating methane and VOC 
emissions using both the single pollutant and multipollutant approaches 
to be reasonable.
    Secondary impacts from the use of instrument air systems are 
indirect, variable, and dependent on the electrical supply used to 
power the compressor. These impacts are expected to be minimal, and no 
other secondary impacts are expected.
    In light of the above, we find that the BSER for reducing methane 
and VOC emissions from natural gas-driven pneumatic controllers at 
natural gas processing plants is the use of zero-emissions controllers. 
Therefore, for NSPS OOOOb, we are proposing to require a natural gas 
emission rate of zero for all pneumatic controllers at natural gas 
processing plants. However, we recognize that there may be technical 
limitations in some situations where zero-emissions controllers may not 
be feasible, and therefore, we are proposing an allowance for the use 
of natural gas-driven pneumatic controllers with an emission rate of 
methane and VOC greater than zero where needed due to functional 
requirements in this BSER determination. Justification of this 
functional need must be provided in an annual report and maintained in 
records.
f. Use of Combustion Devices and VRUs
    Another option that could potentially be used to reduce emissions 
from pneumatic controllers is to collect the emissions from natural gas 
driven continuous bleed controllers and intermittent vent controllers 
and route the emissions through a closed vent system to a control 
device or process. This option is allowed in some State rules. While 
the EPA did not evaluate the cost effectiveness of this option due to a 
lack of available information regarding control system costs and 
feasibility across sites, we think this option could be cost effective 
for owners and operations in certain situations, particularly if the 
site already has a control device to which the emissions from 
controllers could be routed. As this option could be used to achieve 
significant methane and VOC emission reductions (95 percent or 
greater), we are soliciting comment on whether this is a control 
technique used in the industry to reduce emissions from natural gas-
driven pneumatic controllers. We are also interested in information 
related to the performance testing, monitoring, and compliance 
requirements associated with these control devices. Finally, we are 
interested in ideas as to how this option could potentially fit with 
the proposed requirements for pneumatic controllers. For example, if an 
owner or operator determines that a natural gas-driven pneumatic 
controller is required for functional need reasons, the EPA could 
require that emissions be collected and routed to a control device that 
achieves 95, or 98, percent control.
2. EG OOOOc
    The EPA evaluated BSER for the control of methane from existing 
pneumatic controllers (designated facilities) in all segments in the 
Crude Oil and Natural Gas source category covered by the proposed NSPS 
OOOOb and translated the degree of emission limitation achievable 
through application of the BSER into a proposed presumptive standard 
for these facilities that essentially mirrors the proposed NSPS OOOOb.
    First, based on the same criteria and reasoning as explained above, 
the EPA is proposing to define the designated facilities in the context 
of existing pneumatic controllers as those that commenced construction 
on or before November 15, 2021. Based on information available to the 
EPA, we did not identify any factors specific to existing sources that 
would indicate that the EPA should change these definitions as applied 
to existing sources. As such, for purposes of the emission guidelines, 
the definition of a designated facility in terms of pneumatic 
controllers is each individual natural gas driven pneumatic controller 
(continuous bleed or intermittent vent) that vents to the atmosphere.
    Next, the EPA finds that the control options evaluated for new 
sources for NSPS OOOOb are appropriate for consideration in the context 
of existing sources under the EG OOOOc. The EPA finds no reason to 
evaluate different, or additional, control measures in the context of 
existing sources because the EPA is unaware of any control measures, or 
systems of emission

[[Page 63209]]

reduction, for pneumatic controllers that could be used for existing 
sources but not for new sources.
    Next, the methane emission reductions expected to be achieved via 
application of the control measures identified above for new sources 
are also expected to be achieved by application of the same control 
measures to existing sources. The EPA finds no reason to believe that 
these calculations would differ for existing sources as compared to new 
sources because the EPA believes that the baseline emissions of an 
uncontrolled source are the same, or very similar, and the efficiency 
of the control measures are the same, or very similar, compared to the 
analysis above. This is also true with respect to the costs, non-air 
environmental impacts, energy impacts, and technical limitations 
discussed above for the control options identified.
    For the most part, the information presented above regarding the 
costs related to new sources and the NSPS are also applicable for 
existing sources. The instance where the EPA estimated a difference in 
the costs between a new and existing source was for the retrofit of an 
existing production site to use instrument air at sites equipped with 
electrical power. While the equipment needed is the same as for new 
sites, it may be more difficult to design and install a retrofitted 
system. Therefore, the EPA estimates the costs for design and 
installation to be twice that of the costs for new systems (from 
approximately $32,000 for new systems to approximately $64,000 for 
existing systems), resulting in the capital cost of the system being 
approximately $127,000 with an annualized cost of approximately 
$14,000.
    As noted above, the EPA's analysis for this proposal only examined 
the cost of instrument air for the large model plant. The total 
elimination of methane emissions (25 tons per year methane for 
production sites and 10 tons per year methane for transmission and 
storage sites) would be the same for existing sources as presented 
above for new sources. Considering the cost difference, the cost 
effectiveness for production sites is $560 per ton of methane 
eliminated without considering savings, and $365 per ton when 
considering savings. For the transmission and storage segment, the cost 
effectiveness is $1,400 per ton of methane eliminated. These values are 
within the range of what the EPA considers to be reasonable for 
methane. Since none of the other factors are different for existing 
sources when compared to the information discussed above for new 
sources, the EPA concludes that BSER for existing sources and the 
proposed presumptive standard for EG OOOOc to be the requirement to use 
zero-emission controllers. This proposed EG includes the exemption from 
the zero-emission standard for pneumatic controllers in Alaska as 
explained above in the context of the proposed NSPS OOOOb.
b. Possible Phase-In Approach for Existing Sources
    The EPA recognizes there could be different compliance time 
approaches that could be implemented for existing pneumatic 
controllers. The EPA's proposal for compliance times State plans must 
include to meet the requirements of the EG can be found in Section 
XIV.E. As explained there, the EPA is proposing that State plans must 
generally include a 2-year timeline for compliance in the proposed EG, 
but is also soliciting comment on the possibility of the EG requiring 
different compliance timelines for different emission points. 
Specifically, in the context of pneumatic controllers, the EPA is 
further soliciting comment on including a phase-in approach in the EG. 
The EPA recognizes that a phase-in approach may only be appropriate for 
existing sources as new facilities could presumably plan for zero-
emission controllers during construction. A phase-in period could span 
a number of years (e.g., 2 years), to allow owners and operators to 
prioritize conversion of natural gas-driven controllers at existing 
sites based on specific factors (e.g., focus first on sites with onsite 
power, sites with highest production, sites with the highest number of 
controllers). A phase-in approach could also result in the conversion 
of a certain percentage of sites within a given area (e.g., State or 
basin). For example, the State of Colorado requires a minimum of 40 
percent of sites to be converted after 2 years, with 15 percent in year 
1 and 25 percent in year 2. The EPA also recognizes potential 
challenges with a phase-in approach, such as difficulties with 
enforcement and calculation of the percentage converted due to the 
frequency at which sites may change ownership. The EPA solicits comment 
on all aspects of the EG requiring State plans to include a phase-in 
approach, and whether the agency should consider this type of approach 
rather than a single compliance time. The EPA also solicits comment on 
cost and feasibility factors that would enter into adopting and 
designing a phase-in timeline.
c. Natural Gas Processing Plants
    The information presented above regarding the emissions, emission 
reduction options and their effectiveness, costs, and other factors 
related to new natural gas processing plants and the NSPS are also 
applicable for existing sources. Therefore, the EPA concludes that BSER 
for existing sources and the EG OOOOc for natural gas processing plants 
is the requirement to use zero-emission controllers.

D. Proposed Standards for Well Liquids Unloading Operations

1. NSPS OOOOb
a. Background
    In the 2015 NSPS OOOOa proposal (80 FR 56614-56615, September 18, 
2015), the EPA stated that based on available information and input 
received from stakeholders on the 2014 Oil and Natural Gas Sector 
Liquids Unloading Processes review document,\259\ sufficient 
information was not available to propose a standard for liquids 
unloading.
---------------------------------------------------------------------------

    \259\ U.S. Environmental Protection Agency. Oil and Natural Gas 
Sector Liquids Unloading Processes. Report for Oil and Natural Gas 
Sector. Liquids Unloading Processes Review Panel. April 2014.
---------------------------------------------------------------------------

    At that time, the EPA requested comment on technologies and 
techniques that could be applied to new gas wells to reduce emissions 
from liquids unloading events in the future. In the 2016 NSPS OOOOa 
final rule (81 FR 35846, June 3, 2016), the EPA stated that, although 
the EPA received valuable information from the public comment process, 
the information was not sufficient to finalize a national standard 
representing BSER for liquids unloading at that time.
    For this proposal, the EPA conducted a review of available 
information, including new information that became available after the 
2016 NSPS OOOOa rulemaking. As a result of this review, the EPA is 
proposing a zero VOC and methane emission standard under NSPS OOOOb for 
liquid unloading, which can be achieved using non-venting liquids 
unloading methods. In the event that it is technically infeasible or 
not safe to perform liquids unloading with zero emissions, the EPA is 
proposing to require that an owner or operator establish and follow 
BMPs to minimize methane and VOC emissions during liquids unloading 
events to the extent possible. These proposed requirements apply to 
each well liquids unloading event.
    An overall description of liquids unloading, the definition of a 
modification, the definition of affected facility, our BSER analysis, 
and the proposed format of the standard are presented below.

[[Page 63210]]

b. Description
    In new gas wells, there is generally sufficient reservoir pressure/
gas velocity to facilitate the flow of water and hydrocarbon liquids 
through the well head and to the separator to the surface along with 
produced gas. In mature gas wells, the accumulation of liquids in the 
wellbore can occur when the bottom well pressure/gas velocity 
approaches the average reservoir pressure (i.e., volumetric average 
fluid pressure within the reservoir across the areal extent of the 
reservoir boundaries).\260\ This accumulation of liquids can impede and 
sometimes halt gas production. When the accumulation of liquids results 
in the slowing or cessation of gas production (i.e., liquids loading), 
removal of fluids (i.e., liquids unloading) is required in order to 
maintain production. These gas wells therefore often need to remove or 
``unload'' the accumulated liquids so that gas production is not 
inhibited.
---------------------------------------------------------------------------

    \260\ Gordon Smith Review. Oil & Natural Gas Sector Liquids 
Unloading Processes. Submitted: June 16, 2014. Pg. 4.
---------------------------------------------------------------------------

    The 2019 U.S. GHGI estimates almost 175,800 metric tpy of methane 
emissions from liquids unloading events for natural gas systems. 
Specifically, this includes almost 175,800 metric tpy from natural gas 
production, 98,900 metric tpy of which is from liquids unloading events 
that use a plunger lift, and 76,900 metric tpy from liquids unloading 
events that do not use a plunger lift. The overall total represents 3 
percent of the total methane emissions estimated from natural gas 
systems.
    In addition to the GHGI information, we also examined the 
information submitted under GHGRP subpart W. Specifically, we examined 
the GHGRP subpart W liquids unloading emissions data reported for 
Reporting Years 2015 to 2019. The liquids unloading emissions reported 
under GHGRP subpart W include emissions from venting wells, including 
those wells that vent during events that use a plunger lift and wells 
that vent during events that do not use a plunger lift. The information 
reported shows that methane emissions from liquids unloading for a well 
range from 0 to over 1,000 metric tons (1,100 tons) per year. While the 
single well with liquids unloading emissions of 1,100 tpy appears to be 
an outlier, there were over 65 subbasins with reported average liquids 
unloading emissions of 50 tpy or greater per well when disaggregating 
data by year and calculation method. There were over 1,000 wells 
reporting in these subbasins. In addition, there were almost 300 sub-
basins with reported average liquids unloading methane emissions of 10 
tpy or greater per well. There were almost 8,000 wells reporting in 
these subbasins.
    Another source of information reviewed related to emissions 
information from liquids unloading was a study published in 2015 by 
Allen, et al. (University of Texas (UT) Study).\261\ \262\ The UT Study 
collected monitoring data across regions of the U.S. Among other 
findings in this report, for wells that vent more than 100 times per 
year, the average methane emissions per well per year were 27 metric 
tpy, with 95 percent confidence bounds of 10 to 50 Mg/yr (based on the 
confidence bounds in the emissions per event). The monitoring data 
shows that methane emissions from liquids unloading for a well range 
from 1 to 19,500 Mscf per year, or 0.02 to 406 tpy.\263\ As indicated 
by the UT study \264\ emissions information, a small fraction of wells 
account for a large fraction of liquids unloading emissions.
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    \261\ D.T. Allen, D.W. Sullivan, D. Zavala-Araiza, A.P. Pacsi, 
M. Harrison, K. Keen, M.P. Fraser, A. Daniel Hill, B.K. Lamb, R.F. 
Sawyer, J.H. Seinfeld, Methane emissions from process equipment at 
natural gas production sites in the United States: Liquid 
unloadings. Environ. Sci. Technol. 49, 641-648 (2015). doi:10.1021/
es504016r Medline. (UT Study).
    \262\ D.T. Allen, D.W. Sullivan, D. Zavala-Araiza, A.P. Pacsi, 
M. Harrison, K. Keen, M.P. Fraser, A. Daniel Hill, B.K. Lamb, R.F. 
Sawyer, J.H. Seinfeld. Methane Emissions from Process Equipment at 
Natural Gas Production Sites in the United States: Liquid 
Unloadings--Supporting Information; (UT Study--SI). Table S5-1, pg. 
21.
    \263\ UT Study--SI. Tables S3-1 to S3-3, pgs. 11-14.
    \264\ UT Study. pg. 642.
---------------------------------------------------------------------------

c. Modification
    As noted in section XII.D.1.b, new wells typically do not require 
liquids unloading until the point that the accumulation of liquids 
impedes or even stops gas production. At that point, the well must be 
unloaded of liquids to improve the gas flow. One method to accomplish 
this involves the intentional manual venting of the well to the 
atmosphere to improve gas flow. This is done using various techniques. 
One common manual unloading technique diverts the well's flow, 
bypassing the production separator to a lower pressure source, such as 
an atmospheric pressure tank. Under this scenario, venting to the 
atmospheric tank occurs because the separator operates at a higher 
pressure than the atmospheric tank and the well will temporarily flow 
to the atmospheric tank (which has a lower pressure than the 
pressurized separator). Natural gas is released through the tank vent 
to the atmosphere until liquids are unloaded and the flow diverted back 
to the separator. As discussed later in this section, the EPA has 
received feedback that there are technical difficulties with flaring 
vented emissions as a result of the intermittent and surging flow 
characteristic of venting for liquids unloading, and the changing 
velocities during an unloading event.
    Since each unloading event constitutes a physical or operational 
change to the well that has the potential to increase emissions, the 
EPA is proposing to determine each event of liquids unloading 
constitutes a modification that makes a well an affected facility 
subject to the NSPS. See 40 CFR 60.14(a) (``any physical or operational 
change to an existing facility which results in an increase in the 
emission rate to the atmosphere of any pollutant to which a standard 
applies shall be considered a modification within the meaning of 
section 111 of the Act''). The EPA solicits comment on this 
determination.
d. Definition of Affected Facility
    Given that we have proposed to determine that every liquids 
unloading event is a modification, the next step is to define the 
affected facility. The EPA recognizes that methods are commonly 
employed that significantly reduce, or even eliminate, emissions from 
liquids unloading. Therefore, the EPA is co-proposing two options on 
how a modified well due to a liquids unloading event would be covered 
under the rule.
    Under the first option, the affected facility subject to the 
requirements of NSPS OOOOb would be defined as every well that 
undergoes liquids unloading after the effective date of the final rule. 
Under this scenario, a well that undergoes liquids unloading is an 
affected facility regardless of whether the liquids unloading approach 
used results in venting to the atmosphere. This option posits that 
techniques employed to unload liquids that do not increase emissions 
are not to be considered in whether the unloading event is an affected 
facility or not, since the liquids unloading event in their absence 
could result in an emissions increase. This is somewhat analogous to a 
physical change to an existing storage vessel that resulted in the 
ability to increase throughput, and thus emissions. This physical 
change could result in an increase in emissions even if emissions were 
captured and routed back to a process such that the level of pollutant 
actually emitted to the atmosphere did not change. Under this scenario, 
the EPA could request and obtain compliance and enforcement information 
on non-venting liquids

[[Page 63211]]

unloading event methods commonly employed (simple records and reporting 
requirements), as well as venting liquids unloading events.
    Under the second option, the affected facility would be defined as 
every well that undergoes liquids unloading using a method that is not 
designed to totally eliminate venting (i.e., that results in emissions 
to the atmosphere). Under this scenario, if an owner or operator 
employs a method to unload liquids that does not vent to the 
atmosphere, the liquids unloading event would not constitute an 
increase in emissions and therefore, the well would not be an affected 
facility. As such, the first liquids unloading event that vents to the 
atmosphere after the effective date of the final rule, would be an 
affected facility subject to the requirements of NSPS OOOOb. This 
option could create an enforcement information and compliance gap. 
Specifically, the EPA would not be able to obtain compliance assurance 
information on liquids unloading events and emissions/methods and there 
could be a decreased incentive for owners or operators to ensure that 
no unexpected emission episodes occur when a method designed to be non-
venting is used.
    The EPA solicits comments on the two affected facility definition 
options being co-proposed. Specifically, we request comment on whether 
there are implementation and/or compliance assurance concerns that 
arise with applying either of the co-proposed options. In addition, we 
request comment on if there are any appropriate exemptions for 
operations that may be unlikely to result in emissions, such as 
wellheads that are not operating under positive pressure.
e. 2021 BSER Analysis
    The choice of what liquids unloading technique to employ is based 
on an operator well-by-well and reservoir-by-reservoir engineering 
analysis. Because liquids unloading operations entail a number of 
complex science and engineering considerations that can vary across 
well sites, there is no single technological solution or technique that 
is optimal for liquids unloading at all wells. Rather, a large number 
of differing technologies, techniques and practices (i.e., ``methods'') 
have been developed to address the unique characteristics of individual 
wells so as to manage liquids and maintain production. These methods 
include, but are not limited to, manual unloading, velocity tubing or 
velocity strings, beam or rod pumps, electric submergence pumps, 
intermittent unloading, gas lift (e.g., use of a plunger lift), foam 
agents, wellhead compression, and routing the gas to a sales line or 
back to a process.
    Selecting a particular method to meet a particular well's unloading 
needs must be based on a production engineering decision that is 
designed to remove the barriers to production. The situation is further 
complicated as the best method for a particular well can change over 
time. At the onset of liquids loading, techniques that rely on the 
reservoir energy are typically used. Eventually a well's reservoir 
energy is not sufficient to remove the liquids from the well and it is 
necessary to add energy to the well to continue production.
    In the 2016 NSPS OOOOa final rule preamble, the EPA acknowledged 
that operators must select the technique to perform liquids unloading 
operations based on the conditions of the well each time production is 
impaired. During the development of the 2016 NSPS OOOOa rule, the EPA 
considered subcategorization based on the potential for well site 
liquids unloading emissions but determined that the differences in 
liquids unloading events (with respect to both frequency and emissions 
level) are due to specific conditions of a given well at the time the 
operator determines that well production is impaired such that 
unloading must be done. Since owners and operators must select the 
technique to perform an unloading operation based on those conditions, 
and because well conditions change over time, each iteration of 
unloading may require repeating a single technique or attempting a 
different technique that may not have been appropriate under prior 
conditions. As noted above, we recognized that the choice of method to 
unload liquids from a well needs to be a production engineering 
decision based on the characteristics of the well at the time of the 
unloading, and owners and operators need the flexibility to select a 
method that is effective and can be safely employed. No information has 
become available since 2016 that leads the EPA to reach a different 
conclusion regarding subcategorization of wells for the purpose of 
developing standards to address liquids unloading emissions. Further, 
the EPA acknowledges the need for owners and operators to have the 
flexibility to select the most appropriate method(s) and recognize that 
any standard must not impede this flexibility.
    Many methods used for liquids unloading do not result in any 
venting to the atmosphere, provided that the method is properly 
executed. High-level summaries of a few of these methods are provided 
below.\265\
---------------------------------------------------------------------------

    \265\ ``Oil and Natural Gas Sector Liquids Unloading 
Processes''. Report for Oil and Natural Gas Sector Liquids Unloading 
Processes Review Panel. Prepared by U.S. EPA OAQPS. April 2014.
    \265\ 80 FR 56593, September 18, 2015.
---------------------------------------------------------------------------

    A commonly used method employed in the field is the use of a 
plunger lift system. While plunger lift systems often are used in a way 
to minimize emissions, under certain conditions they can be operated to 
unload liquids in a manner that eliminates the need to vent to the 
atmosphere. Plunger lifts use the well's own energy (gas/pressure) to 
drive a piston or plunger that travels the length of the tubing in 
order to push accumulated liquids in the tubing to the surface. 
Specific criteria regarding well pressure and liquid to gas ratio can 
affect applicability. Candidate wells for plunger lift systems 
generally do not have adequate downhole pressure for the well to flow 
freely into a gas gathering system. Optimized plunger lift systems 
(e.g., with smart well automation) can decrease the amount of gas 
vented by up to and greater than 90 percent, and in some instances can 
reduce the need for venting due to overloading. Plunger lift costs 
range from $1,900 to $20,000.\266\ Adding smart automation can cost 
anywhere between an estimated $4,700 to $18,000 depending on the 
complexity of the well. Natural Gas STAR estimates that the annual cost 
savings from avoided emissions from the use of an automated system 
ranges anywhere between $2,400 and $10,241 per year.\267\
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    \266\ U.S. Environmental Protection Agency. Installing Plunger 
Lift Systems in Gas Wells. Office of Air and Radiation: Natural Gas 
Star Program. Washington, DC. 2006.
    \267\ U.S. Environmental Protection Agency. (U.S. EPA) 2011. 
Options for Removing Accumulated Fluid and Improving Flow in Gas 
Wells. Office of Air and Radiation: Natural Gas Star Program. 
Washington, DC. 2011. pg. 1.
---------------------------------------------------------------------------

    Other artificial lifts (e.g., rod pumps, beam lift pumps, pumpjacks 
and downhole separator pumps) are typically used when there is 
inadequate pressure to use a plunger lift, and the only means of 
liquids unloading to keep gas flowing is downhole pump technology. 
Artificial lifts can be operated in a manner that produces no 
emissions. The use of an artificial lift requires access to a power 
source. The capital and installation costs (including location 
preparation, well clean out, artificial lift equipment and pumping 
unit) is estimated to be $41,000 to $62,000/well, with the average cost 
of a pumping unit being between $17,000 to $27,000. \268\
---------------------------------------------------------------------------

    \268\ U.S. EPA, 2011. pg. 9.

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

[[Page 63212]]

    Velocity tubing is smaller diameter production tubing that reduces 
the cross-sectional area of flow, increasing the flow velocity and 
achieving liquids removal without blowing emissions to the atmosphere. 
Generally, a gas flow velocity of 1,000 feet per minute (fpm) is 
necessary to remove wellbore liquids. Velocity tubing strings are 
appropriate for low volume natural gas wells upon initial completion or 
near the end of their productive lives with relatively small liquids 
production and higher reservoir pressure. Candidate wells include 
marginal gas wells producing less than 60 Mcfd. Similarly, coil tubing 
can also be used in wells with lower velocity gas production (i.e., 
seamed coiled tubing may provide better lift due to elimination of 
turbulence in the flow stream). The proper use of velocity tubing is 
considered to be a ``no emissions'' solution. It is also low 
maintenance and effective for low volumes lifted. Velocity lifting can 
be deployed in combination with foaming agents (discussed below). The 
capital and installation costs are estimated to range anywhere from 
$7,000 to $64,000 per well.\269\ Installation requires a well workover 
rig to remove existing production tubing and placement of the smaller 
diameter tubing string in the well.
---------------------------------------------------------------------------

    \269\ U.S. EPA, 2011. pg. 8.
---------------------------------------------------------------------------

    The use of foaming agents (soap, surfactants) as a method to unload 
liquids is implemented by the injection of foaming agents in the 
casing/tubing annulus by a chemical pump on a timer basis. The gas 
bubbling of the soap-water solution creates gas-water foam which is 
more easily lifted to the surface for water removal. This, like the use 
of artificial lifts, requires power to run the surface injection pump. 
Additionally, foaming agents work best if the fluid in the well is at 
least 50 percent water and are not effective for natural gas liquids or 
liquid hydrocarbons. This method requires that the soap supply be 
monitored. If the well is still unable to unload fluid, smaller tubing 
may be needed to help lift the fluids. Foaming agents and velocity 
tubing are reported as possibly being more effective when used in 
combination. No equipment is required in shallow wells. In deep wells, 
a surfactant injection system requires the installation of surface 
equipment and regular monitoring. Foaming agents are reported as being 
low cost ``no emissions'' solution. The capital and startup costs to 
install soap launchers and velocity tubing is estimated to range 
between $7,500 and $67,880, with the monthly cost of the foaming agent 
is approximately $500 per well or approximately $6,000 per year.\270\
---------------------------------------------------------------------------

    \270\ U.S. EPA. 2011. Pg. 8.
---------------------------------------------------------------------------

    These are just a few examples of demonstrated methods that are 
being used in the industry to unload accumulated liquids that impair 
production, that can be implemented without venting and, thus, without 
emissions. As stressed earlier, the selection of a specific method must 
be made based on well-specific characteristics and conditions.
    Since GHGRP subpart W only requires reporting of liquids unloading 
events that resulted in venting of methane, no information is submitted 
regarding those wells that utilize a non-venting method. The EPA is 
also not aware of information that specifies the total number of wells 
that need to undergo liquids unloading. A 2012 report sponsored by the 
API and American Natural Gas Alliance (ANGA) \271\ provided more 
definitive insight into the number of wells that use non-venting 
liquids unloading methods. This report indicated that an estimated 21.1 
percent of plunger equipped wells vent, and 9.3 percent of non-plunger 
equipped wells vent. The EPA interprets this to mean that almost 80 
percent of plunger-equipped wells, and over 90 percent of non-plunger-
equipped wells perform liquids unloading and utilize non-venting 
methods.
---------------------------------------------------------------------------

    \271\ Shires, T. URS Corporation and Lev-On, M. the LEVON Group. 
Characterizing Pivotal Sources of Methane Emissions from Natural Gas 
Production. Summary and Analysis of API and ANGA Survey Responses. 
Prepared for the American Petroleum Institute and the American 
Natural Gas Alliance. September 21, 2012.
---------------------------------------------------------------------------

    As noted above, there is a tremendous range in the emissions from 
liquids unloading reported for individual wells. Further, as discussed 
above, the costs for the non-venting methods range considerably. Also, 
as discussed above, we have determined that the myriad of possible 
reservoir conditions and unloading methods do not lend to any 
reasonable subcategorization of the industry for which representative 
wells could be designed. Therefore, it is not possible to develop a 
``model'' well, or even a series of model wells, that can be used to 
conduct the type of analysis frequently performed for BSER 
determinations that calculates a cost per ton of emissions reduced (or 
in this case eliminated).
    Based on the highest costs included in the cost examples provided 
above, the cost effectiveness of a non-venting method would be 
considered reasonable for wells with annual methane emissions from 
liquids unloading of 16 tpy or greater, or VOC emissions of 3 tpy or 
greater. This upper range is based on the cost of the combination of 
velocity tubing and soap launchers. The upper range of the capital cost 
cited above was $67,800. Annualizing this capital cost at a 7 percent 
interest rate over 10 years, and adding in the $6,000 per year foaming 
agent cost, results in a total annual cost of $15,600. Given the total 
elimination of emissions, the cost effectiveness for a well with 16 tpy 
methane emissions would be $980 per ton of methane reduced, which is a 
level that the EPA considers reasonable for methane. Similarly, for 
VOC, the cost effectiveness for a well with 3 tpy VOC emissions would 
be $5,200 per ton of VOC reduced. This is also a level that the EPA 
considers reasonable. Given the range of costs, it could be reasonable 
even for some wells with annual liquids unloading methane emissions as 
low as 2.5 tpy ($400 per ton of methane reduced (velocity tubing)), or 
VOC emissions as low as 0.2 tpy ($5,000 per ton of VOC reduced 
(velocity tubing)). Based on the GHGRP subpart W data for the years 
2015 through 2019, around 50 percent of the wells that performed 
liquids unloading and reported emissions reported emissions higher than 
these levels.
    While owners and operators must select a liquids unloading method 
that is applicable for the well-specific conditions, they have the 
choice of many methods that can be used to eliminate venting/emissions 
from liquids unloading events. While we do not have information to 
calculate the specific percentage of total wells undergoing liquids 
unloading that use non-venting methods, available information suggests 
that a majority of wells that undergo liquids unloading do not vent. 
The EPA solicits information on the number (or percent) of liquids 
unloading events that vent to the atmosphere versus do not vent to the 
atmosphere under normal conditions and whether there are technical 
obstacles (other than costs) that would not allow liquids unloading to 
be performed without venting.
    CAA section 111(a) requires that the standard reflect the BSER that 
the EPA determines ``has been adequately demonstrated.'' An 
``adequately demonstrated system'' is one that ``has been shown to be 
reasonably reliable, reasonably efficient, and which can reasonably be 
expected to serve the interests of pollution control without becoming 
exorbitantly costly in an economic or environmental way.'' Essex Chem., 
486 F.2d at 433. For the reasons explained above and further elaborated 
below, the EPA considers non-venting methods such as those described 
above

[[Page 63213]]

to have been adequately demonstrated as the BSER for liquids unloading 
events. The complete elimination of emissions from liquids unloading 
with these non-venting methods have been adequately demonstrated in 
practice. The EPA notes that as part of decisions regarding liquids 
unloading, one goal of owners and operators is to eliminate venting to 
prevent the loss of product (natural gas) that could be routed to the 
sales line. States currently encourage the use of methods to eliminate 
emissions unless venting of emissions is necessary for safety reasons 
or when it is technically infeasible to not vent to unload liquids from 
the wellbore. For example, Pennsylvania has a general plan approval 
and/or general operating permit application (BAQ-GPA/GP-5A) that 
specifies that an owner or operator that conducts wellbore liquids 
unloading operations shall use best management practices including, but 
not limited to, plunger lift systems, soaping, swabbing, unless venting 
is necessary for safety to mitigate emissions during liquids unloading 
activities (Best Available Technology (BAT) Compliance Requirements 
under Section L of the General Permit).
    As discussed previously, a majority of wells already conduct 
liquids unloading operations without venting to the atmosphere. Also, 
as discussed previously, there are multiple non-venting liquids 
unloading methods that an owner and operator can select based on a 
well's specific characteristics and conditions. Our evaluation of costs 
shows that there are non-venting liquids unloading methods that could 
be employed to unload liquids that are reasonable given a wide range of 
emission levels. Finally, there are no negative secondary environmental 
impacts that would result from the implementation of methods that would 
eliminate venting of methane and VOC emissions to the atmosphere. In 
light of the above, the EPA considers non-venting liquids unloading 
methods to have been adequately demonstrated to represent BSER for 
reducing methane and VOC emissions during liquids unloading events.
    An ``adequately demonstrated'' system needs not be one that can 
achieve the standard ``at all times and under all circumstances.'' 
Essex Chem., 486 F.2d at 433. That said, as discussed below, the EPA 
recognizes that there may be reasons that a non-venting method is 
infeasible for a particular well, and the proposed rule would allow for 
the use of BMPs to reduce the emissions to the maximum extent possible.
    The EPA recognizes that there may be safety and technical reasons 
why venting to the atmosphere is necessary to unload liquids. In 
addition, it is possible that a well production engineer has already 
explored non-venting options and determined that there was no feasible 
option due to its specific characteristics and conditions. For 
scenarios where a liquids unloading method employed requires venting to 
the atmosphere, the EPA evaluated requiring BMPs that would minimize 
venting to the maximum extent possible. There are several States that 
require the development and implementation of BMPs that minimize 
emissions from liquids unloading events that vent. For example, 
Colorado requires specified BMPs to eliminate or minimize vented 
emissions from liquids unloading. The rule requires that all attempts 
be made to unload liquids without venting unless venting is required 
for safety reasons. If venting is required, the rule requires that 
owners and operators be on site and that they ensure that any venting 
is limited to the maximum extent practicable. Specific BMPs evaluated 
are based on State rules that require BMPs to minimize emissions during 
liquids unloading events are to require operators to monitor manual 
liquids unloading events onsite and to follow procedures that minimize 
the need to vent emissions during an event. This includes following 
specific steps that create a differential pressure to minimize the need 
to vent a well to unload liquids and reducing wellbore pressure as much 
as possible prior to opening to atmosphere via storage tank, unloading 
through the separator where feasible, and requiring closure of all well 
head vents to the atmosphere and return of the well to production as 
soon as practicable. For example, where a plunger lift is used, the 
plunger lift can be operated so that the plunger returns to the top and 
the liquids and gas flow to the separator. Under this scenario, venting 
of the gas can be minimized and the gas that flows through the 
separator can be routed to sales. In situations where production 
engineers select an unloading technique that results or has the 
potential to vent emissions to the atmosphere, owners and operators 
already often implement BMPs in order to increase gas sales and reduce 
emissions and waste during these (often manual) liquids unloading 
activities. We performed a cost and impacts evaluation of the use of 
BMPs to reduce emissions from liquids unloading. This evaluation is 
provided in the NSPS OOOOb and EG TSD for this rulemaking.
    Another potential method for reducing emissions from liquids 
unloading is to capture the vented gas from an unloading event and 
route it to a control device. At the time the Crude Oil and Natural Gas 
Sector Liquids Unloading Processes draft review document was submitted 
to reviewers, the EPA noted that, although the EPA was not aware of any 
specific instances where combustion devices/flares were used to control 
emissions vented from unloading events, the EPA requested information 
on the technical feasibility of flaring as an emissions control option 
for liquids unloading events. Feedback received from reviewers 
indicated that there are technical reasons that flaring during liquids 
unloading is not a feasible option.\272\ Reviewers emphasized that, in 
order to flare gas during liquids unloading, the liquids would need to 
be separated from the well stream, and the intermittent and surging 
flow characteristics of venting for liquids unloading, changing 
velocities during an unloading, and flare ignition considerations for a 
sporadically used flare (i.e., would require either a continuous pilot 
or electronic igniter) would make use of a flare technically and 
financially infeasible.273 274 The reviewers indicated that 
separating the liquids from the well stream would require the well 
stream to flow through a separator with sufficient backpressure to 
separate the gas and liquids. One reviewer noted that after separating 
the liquids from the well stream the gas would then be piped to flare 
system, where the backpressure needed to operate the separator would 
affect the performance of a plunger lift system (if used). Based on 
feedback received on the technical and cost feasibility of using a 
flare to control vented emissions from liquids unloading events 
indicating that a flare cannot be used in all situations, we did not 
consider this option any further in this proposal. However, the EPA is 
soliciting comments about the use of control devices to reduce 
emissions from liquids unloading events. Specifically, we request 
information on the types of wells and unloading events for which 
routing to control is feasible

[[Page 63214]]

and effective, the level of emission reduction achieved, and the 
testing and monitoring requirements that apply.
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    \272\ U.S. Environmental Protection Agency. Oil and Natural Gas 
Sector Liquids Unloading Processes. Report for Crude Oil and Natural 
Gas Sector. Liquids Unloading Processes Review Panel. April 2014.
    \273\ Gordon Smith Review. Oil and Natural Gas Sector Liquids 
Unloading Processes. Review Submitted: June 16, 2014. Pg. 31.
    \274\ Jim Bolander, P.E., Senior Vice President, Southwestern 
Energy (SWN). Review Submitted: April 2014. Pg. 8.
---------------------------------------------------------------------------

    A similar potential method is to capture the vented gas from an 
unloading event and route it to the sales line or back to a process. 
This could potentially represent another method that results in zero 
emissions. While this is not a mitigation option that has been 
specifically mentioned for emissions from liquids unloading, it is a 
common option for other emission sources in the oil and natural gas 
production segment. The EPA is soliciting comments about the option to 
collect and route emissions back to the sales line or to a process. 
Specifically, we request information on the types of wells and 
unloading events for which this option is feasible (if any). If this 
option is feasible, we also request information on the specifics of the 
equipment and processes needed to accomplish this, as well as the 
costs.
    In conclusion, the EPA evaluated several options and identified the 
use of non-venting methods as the BSER for reducing methane and VOC 
emissions during liquids unloading events. However, the EPA recognizes 
there could be situations where it is infeasible to utilize a non-
venting method. Therefore, the EPA proposes to allow for the 
development and implementation of BMPs to reduce emissions to the 
extent possible during liquids unloading where it is infeasible to 
utilize a non-venting method.
f. Format of the Standard
    As discussed under section XII.D.1.d of this preamble, the EPA is 
co-proposing two regulatory approaches to implement the BSER 
determination.
    For Option 1, the affected facility would be defined as every well 
that undergoes liquids unloading. This would mean that wells that 
utilize a non-venting method for liquids unloading would be affected 
facilities and subject to certain reporting and recordkeeping 
requirements. These requirements would include records of the number of 
unloadings that occur and the method used. A summary of this 
information would also be required to be reported in the annual report. 
The EPA also recognizes that under some circumstances venting could 
occur when a selected liquids unloading method that is designed to not 
vent to the atmosphere is not properly applied (e.g., a technology 
malfunction or operator error). Under the proposed rule Option 1 owners 
and operators in this situation would be required to record and report 
these instances, as well as document and report the length of venting 
and what actions were taken to minimize venting to the maximum extent 
possible.
    For wells that utilize methods that vent to the atmosphere, the 
proposed rule would require that they: (1) Document why it is 
infeasible to utilize a non-venting method due to technical, safety, or 
economic reasons; (2) develop BMPs that ensure that emissions during 
liquids unloading are minimized; (3) follow the BMPs during each 
liquids unloading event and maintain records demonstrating they were 
followed; (4) report the number of liquids unloading events in an 
annual report, as well as the unloading events when the BMP was not 
followed. While the proposed rule would not dictate the specific 
practices that must be included, it would specify minimum acceptance 
criteria required for the types and nature of the practices. Examples 
of the types and nature of the required practice elements for BMP are 
provided in section XII.D.1.e, such as those contained in Colorado's 
rule. The EPA is specifically requesting comment on the minimum 
elements that should be required in BMPs and the specificity that the 
proposed rule should include regarding these elements.
    An advantage of this regulatory option is that it would provide 
information to the EPA on the number of liquids unloading events that 
occur and the types of unloading methods used. Having this important 
information would enhance the EPA, the industry, and the public's 
knowledge of emissions from liquids unloading. Option 1 would also 
provide incentive for owners and operators to ensure that non-venting 
methods are applied as they are designed such that unexpected emissions 
do not occur as the result of technology malfunctions or operator 
error. However, it would result in some recordkeeping and reporting 
burden for wells that already use or plan to use non-venting methods 
that would not be incurred under Option 2.
    For Option 2, the affected facility would be defined as every well 
that undergoes liquids unloading using a method that is not designed to 
eliminate venting. The significant difference in this option is that 
wells that utilize non-venting methods would not be affected facilities 
that are subject to the NSPS OOOOb. Therefore, they would not have 
requirements other than to maintain records to demonstrate that they 
used non-venting liquids unloading methods. The requirements for wells 
that use methods that vent would be the same as described above under 
Option 1.
    The EPA believes that this option would provide additional 
incentive for owners and operators to seek ways to overcome potential 
infeasibility issues to ensure that their wells are not affected 
facilities and subject to reporting and recordkeeping requirements. 
This would ultimately result in lower emissions. However, this would 
not provide the EPA information to have a more comprehensive 
understanding of emissions and emission reduction methods from liquids 
unloading. It would also not provide incentive for owners and operators 
to ensure that no unexpected emission episodes occur when a method 
designed to be non-venting is used.
2. EG OOOOc
    As described above, the EPA is proposing that each unloading event 
represents a modification, which will make the well subject to new 
source standards under NSPS. Therefore, existing wells that undergo 
liquids unloading would become subject to NSPS OOOOb. This will mean 
that there will never be a well that undergoes liquids unloading that 
will be ``existing'' for purposes of CAA section 111(d). Therefore, 
there is no need for emissions guidelines or an associated presumptive 
standard under EG OOOOc for liquids unloading operations.

E. Proposed Standards for Reciprocating Compressors

1. NSPS OOOOb
a. Background
    The 2012 NSPS OOOO and the 2016 NSPS OOOOa applied to each 
individual new or reconstructed reciprocating compressor, except for 
those compressors located at a well site, or those located at an 
adjacent well site and servicing more than one well site. The 2016 NSPS 
OOOOa required the reduction of methane and VOC emissions from new, 
reconstructed, or modified reciprocating compressors by replacing rod 
packing systems within 26,000 hours or 36 months of operation, 
regardless of the condition of the rod packing. As an alternative, the 
2016 NSPS OOOOa allowed owners or operators to collect the emissions 
from the rod packing using a rod packing emissions collection system 
that operates under negative pressure and route the rod packing 
emissions to a process through a closed vent system.
    In determining BSER for reciprocating compressors in 2016, the EPA 
determined that the previous determination for NSPS OOOO conducted in 
2011/2012 still represented BSER in 2016. In the 2012 determination the 
EPA first concluded that the piston rod packing wear

[[Page 63215]]

produces fugitive emissions that cannot be captured and conveyed to a 
control device, and that an operational standard pursuant to section 
111(h) of the CAA was appropriate. The EPA conducted analyses of the 
costs and emission reductions of the replacement of rod packing every 3 
years or 26,000 hours of operation and determined that the costs per 
ton of emissions reduced were reasonable for the industry, with the 
exception of compressors at well sites. Based on the 2011 BSER 
analysis, requiring replacement of rod packing every 3 years or 26,000 
hours of operation for well site reciprocating compressors was not 
considered cost effective (almost $57,000 per ton of VOC reduced).\275\ 
No other more stringent control options were evaluated at that time.
---------------------------------------------------------------------------

    \275\ 2011 NSPS OOOO TSD. pg. 6-17.
---------------------------------------------------------------------------

    For this review of the NSPS, the EPA focused on these control 
options which were previously assessed for the 2012 NSPS OOOO and the 
2016 NSPS OOOOa. In addition, we evaluated an option that would require 
annual monitoring to determine if the rod packing needed to be 
replaced. This option is in contrast to the option where replacement is 
required on a fixed (e.g., 3 year) schedule. For this review, BSER was 
evaluated for reciprocating compressors at gathering and boosting 
stations in the production segment (considered to be representative of 
emissions from reciprocating compressors at centralized production 
facilities), at natural gas processing plants, and at sites in the 
transmission and storage segment. In 2012 and in 2016, the EPA 
determined that the cost effectiveness of replacement of the rod 
packing based on the fixed 3-year (or 26,000 hours) schedule was 
unreasonable for reciprocating compressors located at the well site 
(discussed below). No new information has become available to change 
this determination. Therefore, we did not include reciprocating 
compressors located at well sites in our evaluation of regulatory 
options.
    However, as discussed in section XI.L (Centralized Production 
Facilities) of this preamble, the EPA believes the definition of ``well 
site'' in NSPS OOOOa may cause confusion regarding whether 
reciprocating compressors located at centralized production facilities 
are also exempt from the standards. The EPA is proposing a new 
definition for a ``centralized production facility''. The EPA is 
proposing to define centralized production facilities separately from 
well sites because the number and size of equipment, particularly 
reciprocating and centrifugal compressors, is larger than standalone 
well sites which would not be included in the proposed definition of 
``centralized production facilities''. This proposal is necessary in 
the context of reciprocating compressors to distinguish between these 
compressors at centralized production facilities where the EPA has 
determined that the standard should apply, and compressors at 
standalone well sites where the EPA has determined that the standard 
should not apply. In our current analysis, described below, we consider 
the reciprocating compressor gathering and boosting segment emission 
factor as being representative of reciprocating compressor emissions 
located at centralized production facilities. As such, the EPA is 
proposing that reciprocating compressors located at centralized 
production facilities would be subject to the standards in NSPS OOOOb 
and the EG in subpart OOOOc, but reciprocating compressors at well 
sites (standalone well sites) would not.
    As a result of the EPA's review of NSPS OOOOa, we are proposing 
that BSER is to replace the rod packing when, based on annual flow rate 
measurements, there are indications that the rod packing is beginning 
to wear to the point where there is an increased rate of natural gas 
escaping around the packing to unacceptable levels. We are proposing 
that if annual flow rate monitoring indicates a flow rate for any 
individual cylinder as exceeding 2 scfm, an owner or operator would be 
required to replace the rod packing.
b. Description
    In a reciprocating compressor, natural gas enters the suction 
manifold, and then flows into a compression cylinder where it is 
compressed by a piston driven in a reciprocating motion by the 
crankshaft powered by an internal combustion engine. Emissions occur 
when natural gas leaks around the piston rod when pressurized natural 
gas is in the cylinder. The compressor rod packing system consists of a 
series of flexible rings that create a seal around the piston rod to 
prevent gas from escaping between the rod and the inboard cylinder 
head. However, over time, during operation of the compressor, the rings 
become worn and the packaging system needs to be replaced to prevent 
excessive leaking from the compression cylinder.
    As discussed previously, emissions from a reciprocating compressor 
occur when, over time, during operation of the compressor, the rings 
that form a seal around the piston rod that prevents gas from escaping 
become worn. This results in increasing emissions from the compression 
cylinder. Based on the 2021 GHGI,\276\ the methane emissions from 
reciprocating compressors in 2019 represented 14 percent of the total 
methane emissions from natural gas systems in the Crude Oil and Natural 
Gas Industry sector. For segments where the GHGI included a breakdown 
of methane emissions for reciprocating compressors, the reported 
emissions were 309,500 metric tons for the gathering and boosting 
segment, 46,700 metric tons for the processing segment, 406,500 metric 
tons for the transmission segment, and 103,200 metric tons for the 
storage segment.
---------------------------------------------------------------------------

    \276\ U.S. Environmental Protection Agency. Inventory of U.S. 
Greenhouse Gas Emissions and Sinks (1990-2019). Published in 2021. 
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2019.
---------------------------------------------------------------------------

c. Affected Facility
    For purposes of the NSPS, the reciprocating compressor affected 
facility is a single reciprocating compressor. A reciprocating 
compressor located at a well site, or an adjacent well site and 
servicing more than one well site, is not an affected facility under 
the proposed rule for the NSPS OOOOb. As discussed above, the EPA is 
proposing that the affected facility includes reciprocating compressors 
located at centralized production facilities and the affected facility 
exception for ``a well site, or an adjacent well site servicing more 
than one well site'' applies to standalone well sites and not 
centralized production facilities.
d. 2021 BSER Analysis
    The methodology used for estimating emissions from reciprocating 
compressor rod packing is consistent with the methodology developed for 
the 2012 NSPS OOOO BSER analysis and then also used to support the 2016 
NSPS OOOOa BSER. This approach uses volumetric methane emission factors 
referenced in the EPA/GRI study \277\ as the basis, multiplied by the 
density of methane. These factors were per cylinder, so they were 
multiplied by the average number of cylinders per reciprocating 
compressor at each oil and gas industry segment, the pressurized factor 
(percentage of hours per year the compressor was pressurized), and 
8,760 hours (number of hours in a year). Once the methane emissions 
were calculated, VOC emissions were calculated by multiplying the 
methane by ratios developed based on representative gas composition. 
The specific ratios that were used for this analysis were 0.278

[[Page 63216]]

pounds VOC per pound of methane for the production and processing 
segments, and 0.0277 pounds VOC per pound of methane for the 
transmission and storage segment. The resulting baseline emissions from 
reciprocating compressors were 12.3 tpy methane (3.4 tpy VOC) from 
gathering and boosting stations, 23.3 tpy methane (6.5 tpy VOC) from 
natural gas processing plants, 27.1 tpy methane (0.75 tpy VOC) from 
transmission stations, and 28.2 tpy methane (0.78 tpy VOC) from storage 
facilities.
---------------------------------------------------------------------------

    \277\ EPA/GRI. (1996). Methane Emissions from the Natural Gas 
Industry: Volume 8--Equipment Leaks.
---------------------------------------------------------------------------

    Reducing emissions that result from the leaking of natural gas past 
the piston rod packing can be accomplished through several approaches 
including: (1) Specifying a frequency for the replacement of the 
compressor rod packing, (2) monitoring the emissions from the 
compressor and replacing the rod packing when the results exceed a 
specified threshold, (3) specifying a frequency for the replacement of 
the piston rod, (4) requiring the use of specific rod packing 
materials, and/or (5) capturing the leaking gas and routing it either 
to a process or a control device.
    There was either insufficient information to establish BSER or it 
was determined that the option cannot be applied in all situations for 
approach options (3) through (5). These are discussed briefly below.
    Like the packing rings, piston rods on reciprocating compressors 
also deteriorate. Piston rods, however, wear more slowly than packing 
rings, having a life of about 10 years.\278\ Rods wear ``out-of-round'' 
or taper when poorly aligned, which affects the fit of packing rings 
against the shaft (and therefore the tightness of the seal) and the 
rate of ring wear. An out-of-round shaft not only seals poorly, 
allowing more leakage, but also causes uneven wear on the seals, 
thereby shortening the life of the piston rod and the packing seal. 
Replacing or upgrading the rod can reduce reciprocating compressor rod 
packing emissions. Also, upgrading piston rods by coating them with 
tungsten carbide or chrome reduces wear over the life of the rod. We 
assume that operators will choose, at their discretion, when to 
replace/realign or retrofit the rod as part of regular maintenance 
procedures and replace the rod when appropriate when the compressor is 
out of service for other maintenance such as rod packing replacement. 
Although replacing/realigning or retrofitting the rod has been 
identified as a potential methane and VOC emission reduction option for 
reciprocating compressors, there is insufficient information on its 
emission reduction potential and use throughout the industry. 
Therefore, we did not evaluate this option any further as BSER for this 
proposal.
---------------------------------------------------------------------------

    \278\ U.S. Environmental Protection Agency. Lessons Learned from 
Natural Gas STAR Partners. Reducing Methane Emissions from 
Compressor Rod Packing Systems. Natural Gas STAR Program. 2006.
---------------------------------------------------------------------------

    Although specific analyses have not been conducted, there may be 
potential for reducing methane and VOC emissions by updating rod 
packing components made from newer materials, which can help improve 
the life and performance of the rod packing system. One option is to 
replace the bronze metallic rod packing rings with longer lasting 
carbon-impregnated Teflon rings. Compressor rods can also be coated 
with chrome or tungsten carbide to reduce wear and extend the life of 
the piston rod. Although changing the rod packing material has been 
identified as a potential methane and VOC emission reduction option for 
reciprocating compressors, there is insufficient information on its 
emission reduction potential and use throughout the industry. 
Therefore, we did not evaluate this option any further as BSER for this 
proposal.
    The 2016 NSPS OOOOa includes the alternative to route the emissions 
from reciprocating compressors to a process. One estimate obtained by 
the EPA states that a gas recovery system can result in the elimination 
of over 99 percent of methane emissions that would otherwise occur from 
the venting of the emissions from the compressor rod packing. The 
emissions that would have been vented are combusted in the compressor 
engine to generate power. It was estimated that, if a facility is able 
to route rod packing vents to a VRU system, it is possible to recover 
approximately 95-100 percent of emissions. As a comparison, the EPA 
estimated that the 3-year/26,000-hour changeout results in between 55 
and 80 percent emission reduction. Therefore, an option to achieve 
additional emission reductions could be to require routing the 
reciprocating compressor emissions to a process/through a closed vent 
system under negative pressure. Although this was a control option 
considered in the 2016 NSPS OOOOa (and included as an alternative), the 
EPA did not require routing to a process for all compressors because at 
that time there was insufficient information to require this as a 
control for all reciprocating compressors. The EPA received feedback 
that this option cannot be applied in every installation, and has not 
received any new information that indicates this has changed. Thus, 
this option was not considered further as a requirement but for this 
proposal, as with the 2016 NSPS OOOOa, it is considered to be an 
acceptable alternative to mitigate methane and VOC emissions where it 
is technically feasible to apply.
    Similarly, another option evaluated as having the potential to 
achieve methane and VOC emission reductions was to require the 
collection of emissions in a closed vent system and routing them to a 
flare or other control device. If the gas is routed to a flare, 
approximately 95 percent of the methane and VOC would be reduced. The 
EPA has expressed historically and maintains that combustion is not 
believed to be a technically feasible control option for reciprocating 
compressors because, as detailed in the 2011 NSPS OOOO TSD, routing of 
emissions to a control device can cause positive back pressure on the 
packing, which can cause safety issues due to gas backing up in the 
distance piece area and engine crankcase in some designs. The EPA has 
not identified any new information to indicate that this has changed. 
Therefore, this option was not considered further as BSER for this 
proposal.
    The remaining two control option approaches that were evaluated 
further for this proposal include: (1) Specifying a frequency for the 
replacement of the compressor rod packing (equivalent to the frequency 
used in the 2016 NSPS OOOOa BSER control level), and (2) monitoring the 
emissions from the compressor and replacing the rod packing when the 
results exceed a specified threshold. Both of these approaches would 
reduce the escape of natural gas from the piston rod. No wastes would 
be created (other than the worn packing that is being replaced) and no 
wastewater would be generated.
    As noted previously, periodically replacing the packing rings 
ensures the correct fit is maintained between packing rings and the 
rod, thereby limiting emissions occurring around the flexible rings 
that fit around the shaft by recreating a seal against leakage that may 
have been lost due to wear. The potential emission reductions for 
reciprocating compressors at gathering and boosting stations, 
processing plants, and transmission and storage facilities were 
calculated by comparing the average rod packing emissions with the 
average emissions from newly installed and worn-in rod packing. As 
noted above, because the EPA concluded that the cost effectiveness of 
this option was extremely unreasonable for reciprocating compressors at 
well sites in previous BSER analyses (see the 2011 NSPS OOOO TSD, 
section 2.2; 80 FR 56620, September 18, 2015), and since no new 
information was identified that

[[Page 63217]]

would change this outcome as it relates to stand alone well sites, 
reductions and costs were not re-evaluated in this analysis for 
reciprocating compressors at production well sites.
    The emissions after the replacement of the rod packing were 
calculated using the methodology used under previous NSPS actions (see 
NSPS OOOOb and EG TSD, section 7.1). The resulting emission reductions 
used for the analysis represented the emission reductions expected in 
the year the rod packing is replaced. It is expected that there would 
be an increase in the emissions (and decrease in the emission 
reductions) from a compressor where the rod packing was replaced the 
second and third years before the next replacement. As noted above, 
this assumed reduction was between 55 and 80 percent depending on the 
location of the compressor.
    The costs of replacing rod packing were obtained from a Natural Gas 
STAR Lessons Learned document \279\ and the dollars were converted to 
2019 dollars. The estimated cost to replace the packing rings in 2019 
dollars was estimated to be $1,920 per cylinder. It was assumed that 
rod packing replacement would occur during planned shutdowns and 
maintenance, and therefore no additional travel costs would be incurred 
for implementing a rod packing replacement program. Since the assumed 
number of cylinders differs for reciprocating compressors at different 
segments, this means the capital costs also vary. These estimated 
capital costs are $6,350 at gathering and boosting and transmission 
stations, $4,800 at processing plants, and $8,650 at storage stations.
---------------------------------------------------------------------------

    \279\ EPA (2006). Lessons Learned: Reducing Methane Emissions 
from Compressor Rod Packing Systems. Natural Gas STAR. Environmental 
Protection Agency.
---------------------------------------------------------------------------

    The 26,000-hour replacement frequency used for the cost impacts in 
the 2011 NSPS OOOO TSD and 2016 NSPS OOOOa TSD was determined using a 
weighted average of the annual percentage of time that reciprocating 
compressors are pressurized. The weighted average percentage was 
calculated to be 98.9 percent. This percentage was multiplied by the 
total number of hours in 3 years to obtain a value of 26,000 hours. 
This calculates to an average of 3.8 years for gathering and boosting 
compressors, 3.3 years for processing compressors, 3.8 years for 
transmission compressors, and 4.4 years for storage compressors. The 
calculated years were assumed to be the equipment life of the 
compressor rod packing and were used to calculate the capital recovery 
factor for each of the segments. Assuming an interest rate of 7 
percent, the capital recovery factors were calculated to be 0.3093, 
0.3498, 0.3093, and 0.2695 for the gathering and boosting part of 
production, processing, transmission, and storage segments, 
respectively.
    The capital costs were calculated using the average rod packing 
cost noted above and the average number of cylinders per compressor 
(which differs depending on sector segment). The annual capital costs 
were calculated using the capital costs and the capital recovery 
factors. The estimated annual costs ranged from $1,700 at processing 
plants to just over $2,300 at storage facilities. Note that these 
estimated costs represent the costs, and associated emission 
reductions, that would occur in the year when the rod packing was 
changed. There would be no costs for the other two years in the three-
year cycle. The costs presented for gathering and boosting segment 
reciprocating compressors represent the estimated costs assumed for 
reciprocating compressors located at centralized production facilities.
    There are monetary savings associated with the amount of natural 
gas saved with reciprocating compressor rod packing replacement. 
Monetary savings associated with the amount of gas saved with 
reciprocating compressor rod packing replacement were estimated using a 
natural gas price of $3.13 per Mcf. Estimated savings were only applied 
for gathering and boosting stations and processing plants, as it is 
assumed the owners of the compressor station do not own the natural gas 
that is compressed at the station.
    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the cost effectiveness of 
replacement of the reciprocating rod packing within 26,000 hours or 36 
months of operation, regardless of the condition of the rod packing, is 
approximately $290 per ton of methane reduced for gathering and 
boosting ($100 per ton if gas savings are considered), $90 per ton of 
methane reduced for the processing segment (net savings if gas savings 
are considered), $90 per ton of methane reduced for the transmission 
segment, and $110 per ton of methane reduced for the storage segment. 
Using the multipollutant approach, where half the cost of control is 
assigned to the methane reduction and half to the VOC reduction, the 
cost effectiveness of replacement of the reciprocating rod packing 
within 26,000 hours or 36 months of operation, regardless of the 
condition of the rod packing, is approximately $140 per ton of methane 
reduced for gathering and boosting ($50 per ton if gas savings are 
considered), $45 per ton of methane reduced for the processing segment 
(net savings if gas savings are considered), $45 per ton of methane 
reduced for the transmission segment, and $50 per ton of methane 
reduced for the storage segment.
    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the VOC cost effectiveness 
of replacement of the reciprocating rod packing within 26,000 hours or 
36 months of operation, regardless of the condition of the rod packing, 
is approximately $1,030 per ton of VOC reduced for gathering and 
boosting ($380 per ton if gas savings are considered), $330 per ton of 
VOC reduced for the processing segment (net savings if gas savings are 
considered), $3,260 per ton of VOC reduced for the transmission 
segment, and $3,860 per ton of VOC reduced for the storage segment. 
Using the multipollutant approach, where half the cost of control is 
assigned to the methane reduction and half to the VOC reduction, the 
cost effectiveness of replacement of the reciprocating rod packing 
within 26,000 hours or 36 months of operation, regardless of the 
condition of the rod packing, is approximately $520 per ton of VOC 
reduced for gathering and boosting ($190 per ton if gas savings are 
considered), $160 per ton of VOC reduced for the processing segment 
(net savings if gas savings are considered), $1,630 per ton of VOC 
reduced for the transmission segment, and $1,930 per ton of VOC reduced 
for the storage segment.
    As an alternative to replacing the rod packing on a fixed schedule, 
another option is to replace the rod packing when, based on 
measurements, there are indications that the rod packing is beginning 
to wear to the point where there is an increased rate of natural gas 
escaping around the packing to unacceptable levels. This is an approach 
required by the California Greenhouse Gas Emission Regulation and in 
Canada. The California Greenhous Gas Emission Regulation requires that 
the rod packing/seal be tested during periodic inspections and, if the 
rod packing/seal leak concentration exceeds the specified threshold of 
2 scfm/cylinder, repairs must be made within 30 days.\280\ Similarly, 
certain Canadian jurisdictions require periodic monitoring measurements 
of rod packing vent

[[Page 63218]]

volumes (typically annually) for existing reciprocating compressors. 
Where specified vent volumes are exceeded, the rules require corrective 
action be taken to reduce the flow rate to below or equal to a 
specified limit, as demonstrated by a remeasurement. Vent volume 
thresholds specified that would result in the need for corrective 
action vary from 0.49 to 0.81 scfm/cylinder.\281\
---------------------------------------------------------------------------

    \280\ State of California Air Resources Board (CARB). 
``Regulation for Greenhouse Gas Emission Standards for Crude Oil and 
Natural Gas Facilities.'' Oil and Gas Final Regulation Order 
(ca.gov).
    \281\ Canadian Federal standards: http://gazette.gc.ca/rp-pr/p2/2018/2018-04-26-x1/pdf/g2-152x1.pdf; Discussion Draft Regulation 
26.11.41 (maryland.gov); MAP-Technical-Report-December-19-2019-
FINAL.pdf (nm.gov).
---------------------------------------------------------------------------

    This approach is similar to an approach identified in the Natural 
Gas STAR Program referred to as ``Economic Packing and Piston Rod 
Replacement.'' \282\ Under this approach, facilities use specific 
financial objectives and monitoring data to determine emission levels 
at which it is cost effective to replace rings and rods. Benefits of 
calculating and utilizing this ``economic replacement threshold'' 
include methane and VOC emission reductions and natural gas cost 
savings. Using this approach, one Natural Gas STAR partner reportedly 
achieved savings of over $233,000 annually at 2006 gas prices. An 
economic replacement threshold approach can also result in operational 
benefits, including a longer life for existing equipment, improvements 
in operating efficiencies, and long-term savings. The EPA is not 
proposing to establish a financial objective or economic replacement 
threshold in this proposal, but the costs and emission reductions of 
replacing rod packing based on monitoring from this program were 
considered in the analysis discussed below.
---------------------------------------------------------------------------

    \282\ U.S. Environmental Protection Agency. Lessons Learned from 
Natural Gas STAR Partners. Reducing Methane Emissions from 
Compressor Rod Packing Systems. Natural Gas STAR Program. 2006.
---------------------------------------------------------------------------

    The elements of such a program include establishing a frequency of 
monitoring, identifying a threshold where action is required to reduce 
emissions, and specifying the action for reducing emissions. The option 
defined by the EPA and evaluated below is for annual monitoring and 
requiring the replacement of the rod packing if the measured flow rate 
for any individual cylinder exceeds 2 scfm. This threshold is 
consistent with California's regulation. However, this option differs 
from the California regulation in that it would require a complete 
replacement of the rod packing if this threshold is exceeded, where 
California allows repair sufficient to reduce the flow rate back below 
2 scfm. The 2 scfm flow rate threshold was established based on 
manufacturer guidelines indicating that a flow rate of 2 scfm or 
greater was considered indicative of rod packing failure.\283\
---------------------------------------------------------------------------

    \283\ State of California. Air Resources Board Public Hearing to 
Consider the Proposed Regulation for Greenhouse Gas Emission 
Standards for Crude Oil and Natural Gas Facilities. Staff Report: 
Initial Statement of Reasons. pgs. 96-97.
---------------------------------------------------------------------------

    We estimated the emission reductions from requiring annual flow 
rate monitoring and repair/replacement of packing when the measured 
flow rate exceeds 2 scfm total gas during pressurized operation. Based 
on California's background regulatory documentation, information 
provided to the State indicated that the average leak rate for those 
compressors emitting more than 2 scfm was about 3 scfm during 
pressurized operation, and less than 2 scfm during pressurized idle and 
unpressurized states. Therefore, we assumed that the leak rate for 
compressors emitting more than 2 scfm was about 3 scfm during 
pressurized operation. As indicated above for the fixed schedule rod 
packing replacement option, based on the 2011 NSPS OOOO TSD and 2016 
NSPS OOOOa TSD, the average emissions from a newly installed rod 
packing are assumed to be 11.5 scfh per cylinder.\284\ Using a ratio of 
0.829 methane: Total natural gas ratio, 3 scfm total gas is 
approximately 2.49 scfm (149.2 scfh) methane. This compressor emission 
rate, which was used for all industry segments, was converted to an 
annual mass emission rate by applying segment-specific pressurized 
factors, then converted to a mass basis.
---------------------------------------------------------------------------

    \284\ 2011 TSD, pg. 6-13.
---------------------------------------------------------------------------

    The estimated percent reduction in methane emissions that would be 
achievable from reducing 149.2 scfh methane/cylinder to 11.5 scfh 
methane/cylinder (average emissions from a newly installed rod packing/
cylinder) is 92 percent. We applied this percent reduction in methane 
emissions and estimated reciprocating compressor methane and VOC 
emission reductions that would be achieved from repairing/replacing rod 
packing based on the annual flow rate monitoring option. The 
calculations assume that all cylinders are emitting at 3 scfm, and that 
the rod packings for all compressor cylinders are replaced. This 
represents the emission reductions expected for the year in which the 
rod packings are replaced. Emissions would be expected to increase (and 
emission reductions decrease) in subsequent years until the next time 
the annual measurements require that the rod packing be replaced.
    The capital and annual costs of replacing the rod packings are the 
same as presented above for the fixed interval rod packing replacement 
option. In addition, this option would include the costs associated 
with the annual flow measurements. The estimated costs of this 
monitoring are based on the costs for annual flow rate monitoring under 
GHGRP subpart W for similar flow rate annual measurement requirements 
($597). The capital costs associated with replacing compressor rod 
packing would only occur in the year when packing is required to be 
replaced. The monitoring costs would be incurred every year.
    Additionally, the cost estimates assume that the packing of all 
compressor cylinders would need to be replaced (which is unlikely to be 
the case in many instances) and are therefore conservative estimates. 
Support information for the California rule cites data indicating that 
approximately 14 percent of compressors measurements indicated a leak 
rate of over 2 scfm per cylinder. Based on an average of 3.45 
cylinders/compressor, California assumed that the packing for 2 
cylinders/compressor would need to be replaced to come into compliance 
with the 2 scfm standard (57.9 percent).\285\
---------------------------------------------------------------------------

    \285\ Based on Appendix B. Economic Analysis. State of 
California. Air Resources Board. Proposed Regulation for Greenhouse 
Gas Emission Standards for Crude Oil and Natural Gas Facilities. pg. 
B-28. Notice Package for Oil and Gas Reg (ca.gov); State of 
California. Air Resources Public Hearing to Consider the Proposed 
Regulation for Greenhouse Gas Emission Standards for Crude Oil and 
Natural Gas Facilities. Staff Report: Initial Statement of Reasons. 
Date of Release: May 31, 2016. pg. 99.
---------------------------------------------------------------------------

    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the cost effectiveness of 
the annual monitoring option is approximately $230 per ton of methane 
reduced for gathering and boosting ($40 per ton if gas savings are 
considered), $110 per ton of methane reduced for the processing segment 
(net savings if gas savings are considered), $100 per ton of methane 
reduced for the transmission segment, and $110 per ton of methane 
reduced for the storage segment. Using the multipollutant approach, 
where half the cost of control is assigned to the methane reduction and 
half to the VOC reduction, the cost effectiveness of replacement of the 
reciprocating rod packing based on the annual monitoring approach is 
approximately $110 per ton of methane reduced for gathering and 
boosting ($20 per ton if gas savings are considered), $50 per ton of 
methane reduced for the processing segment (net savings if gas savings 
are considered), $50 per ton of methane reduced for the transmission

[[Page 63219]]

segment, and $60 per ton of methane reduced for the storage segment.
    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the VOC cost effectiveness 
of the annual monitoring option is approximately $810 per ton of VOC 
reduced for gathering and boosting ($160 per ton if gas savings are 
considered), $380 per ton of VOC reduced for the processing segment 
(net savings if gas savings are considered), $3,700 per ton of VOC 
reduced for the transmission segment, and $4,100 per ton of VOC reduced 
for the storage segment. Using the multipollutant approach, where half 
the cost of control is assigned to the methane reduction and half to 
the VOC reduction, the cost effectiveness of replacement of the 
reciprocating rod packing based on the annual monitoring approach is 
approximately $410 per ton of VOC reduced for gathering and boosting 
($80 per ton if gas savings are considered), $190 per ton of VOC 
reduced for the processing segment (net savings if gas savings are 
considered), $1,850 per ton of VOC reduced for the transmission 
segment, and $2,040 per ton of VOC reduced for the storage segment.
    We also assessed the incremental cost effectiveness of the annual 
monitoring option compared to the fixed 3-year/26,000 replacement 
schedule. Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the incremental cost 
effectiveness (without natural gas savings) from the fixed replacement 
option to the annual monitoring option for methane is approximately 
$130 per ton for gathering and boosting stations, $210 per ton for 
processing plants, $180 per ton for transmission stations, and $140 per 
ton for storage facilities. For VOC, the incremental cost effectiveness 
is approximately $480 per ton for gathering and boosting stations, $750 
per ton for processing plants, $6,600 per ton for transmission 
stations, and $5,150 per ton for storage facilities.
    The cost effectiveness of both options (fixed schedule and annual 
monitoring) are reasonable for methane and VOC using either the single 
pollutant or multipollutant approach. The incremental cost 
effectiveness in going from the fixed schedule option to the annual 
monitoring option is reasonable for all scenarios, with the exception 
of VOC for transmission stations. Therefore, based on the consideration 
of the costs in relation to the emission reductions, the EPA finds that 
the annual monitoring option is the most reasonable option.
    Further, as discussed above, California requires reciprocating 
compressor annual rod packing flow rate monitoring and repair and or 
replacement of the packing where flow rate monitoring indicates a 
measurement that exceeds 2 scfm. This further supports the 
reasonableness of a monitoring program.
    Neither the fixed schedule rod packing replacement option nor the 
rod packing replacement based on annual monitoring option would result 
in secondary emissions impacts as both options would reduce the escape 
of natural gas from the piston rod. No wastes would be created (other 
than the worn packing that is being replaced) and no wastewater would 
be generated. An advantage related to the replacement of rod packing 
for reciprocating compressors based on annual rod packing monitoring is 
that it would only require replacement of the rod packing where 
monitoring of the rod packing indicates wear and increasing flow rate/
emissions to unacceptable levels. This optimizes the output of capital 
expenditures to focus on emissions control where an increased emissions 
potential is identified.
    In light of the above we determined that annual rod pack flow rate 
monitoring and replacement of the packing where flow rate monitoring 
indicates a measurement that exceeds 2 scfm represents BSER for NSPS 
OOOOb for this proposal for all segments including reciprocating 
compressors located at centralized productions facilities (with the 
exception of compressors at stand-alone well sites). As in the 2016 
NSPS OOOOa, the EPA is proposing to allow the collection and routing of 
emissions to a process as an alternative standard because that option 
would achieve emission reductions equivalent to, or greater than, the 
proposed standard for NSPS OOOOb.
    The affected facility based on EPA's review would continue to be 
each reciprocating compressor not located at a well site, or an 
adjacent well site and servicing more than one well site. As discussed 
above, the EPA is proposing a new definition for a ``centralized 
production facility''. The EPA is proposing to define centralized 
production facilities separately from well sites because the number and 
size of equipment, particularly reciprocating and centrifugal 
compressors, is larger than standalone well sites which would not be 
included in the proposed definition of ``centralized production 
facilities''. Thus, the EPA is proposing that reciprocating compressors 
located at centralized production facilities would be subject to the 
standards in NSPS in OOOOb, but reciprocating compressors at well sites 
(standalone well sites) would not.
2. EG OOOOc
    The EPA evaluated BSER for the control of methane from existing 
reciprocating compressors (designated facilities) in all segments in 
the Crude Oil and Natural Gas source category covered by the proposed 
NSPS OOOOb and translated the degree of emission limitation achievable 
through application of the BSER into a proposed presumptive standard 
for these facilities that essentially mirrors the proposed NSPS OOOOb.
    First, based on the same criteria and reasoning as explained above, 
the EPA is proposing to define the designated facility in the context 
of existing reciprocating compressors as those that commenced 
construction on or before November 15, 2021. Based on information 
available to the EPA, we did not identify any factors specific to 
existing sources that would indicate that the EPA should alter this 
definition as applied to existing sources. Next, the EPA finds that the 
control measures evaluated for new sources for NSPS OOOOb are 
appropriate for consideration for existing sources under the EG OOOOc. 
The EPA finds no reason to evaluate different, or additional, control 
measures in the context of existing sources because the EPA is unaware 
of any control measures, or systems of emission reduction, for 
reciprocating compressors that could be used for existing sources but 
not for new sources. Next, the methane emission reductions expected to 
be achieved via application of the control measures identified above to 
new sources are also expected to be achieved by application of the same 
control measures to existing sources. The EPA finds no reason to 
believe that these calculations would differ for existing sources as 
compared to new sources because the EPA believes that the baseline 
emissions of an uncontrolled source are the same, or very similar, and 
the efficiency of the control measures are the same, or very similar, 
compared to the analysis above. This is also true with respect to the 
costs, non-air environmental impacts, energy impacts, and technical 
limitations discussed above for the control options identified.
    The EPA has not identified any costs associated with applying these 
controls at existing sources, such as retrofit costs, that would apply 
any differently than, or in addition to, those costs assessed above 
regarding application of the identified controls to new sources. The 
cost effectiveness values for the

[[Page 63220]]

proposed presumptive standard of replacement of the rod packing based 
on an annual monitoring threshold is approximately $230 per ton of 
methane reduced ($40 per ton if gas savings are considered) for the 
gathering and boosting segment (including reciprocating compressors 
located at centralized tank facilities), $110 per ton of methane 
reduced for the processing segment (net savings if gas savings are 
considered), $100 per ton of methane reduced for the transmission 
segment, and $110 per ton of methane reduced for the storage segment.
    In summary, the EPA did not identify any factors specific to 
existing sources, as opposed to new sources, that would alter the 
analysis above for the proposed NSPS OOOOb as applied to the designated 
pollutant (methane) and the designated facilities (reciprocating 
compressors). As a result, the proposed presumptive standard for 
existing reciprocating compressors is as follows.
    For reciprocating compressors in the gathering and boosting segment 
(including reciprocating compressors located at centralized tank 
facilities), processing, and transmission and storage segments, the 
presumptive standard is replacement of the rod packing based on an 
annual monitoring threshold. Specifically, the presumptive standard 
would require an owner or operator of a reciprocating compressor 
designated facility to monitor the rod packing flow rate annually. When 
the measured leak rate exceeds 2 scfm (in pressurized mode), the 
standard would require replacement of the rod packing. As an 
alternative, the presumptive standard would be routing rod packing 
emissions to a process via a closed vent system under negative 
pressure.

F. Proposed Standards for Centrifugal Compressors

1. NSPS OOOOb
a. Background
    The 2012 NSPS OOOO and the 2016 NSPS OOOOa applied to each wet seal 
compressor not located at a well site, or an adjacent well site and 
servicing more than one well site. The 2016 NSPS OOOOa required methane 
and VOC emissions be reduced from each centrifugal compressor wet seal 
fluid degassing system by 95.0 percent. Compliance with this 
requirement allowed routing of emission from the wet seal fluid 
degassing system to a control device or to a process. Dry seal 
compressors were not subject to requirements under the 2016 NSPS OOOOa.
    In determining BSER for wet seal compressors in 2016, the EPA 
determined that the previous determination for NSPS OOOO conducted in 
2011/2012 still represented BSER for the control of VOC in 2016. In 
addition, the EPA determined that analogous control of methane 
represented BSER. In the 2012 determinations, the EPA conducted 
analyses of the cost and emission reductions of (1) requiring the 
conversion of a wet seal system to a dry seal system, and (2) routing 
to a control device or process. The 2011 NSPS OOOO rule (76 FR 52738, 
52755, August 23, 2011) proposed an equipment standard that would have 
required the use of dry seals to limit the VOC emissions from new 
centrifugal compressors. At that time, the EPA solicited comments on 
the emission reduction potential, cost, and any technical limitations 
for the option of routing the gas back to a low-pressure fuel stream to 
be combusted as fuel gas. In addition, in 2011 (76 FR 52738), the EPA 
solicited comments on whether there are situations or applications 
where a wet seal is the only option, because a dry seal system is 
infeasible or otherwise inappropriate. The EPA received information 
indicating that the integration of a centrifugal compressor into an 
operation may require a certain compressor size or design that is not 
available in a dry seal model, and in the case of capture of emissions 
with routing to a process, there may not be down-stream equipment 
capable of handling a low-pressure fuel source. In the final 2012 NSPS 
OOOO rule, the EPA made the determination that the replacement of wet 
seals with dry seals and routing to a process was not technically 
feasible or practical for some centrifugal compressors, and also that 
the costs per ton of emissions reduced were reasonable for routing 
emissions to a control device or process. No other more stringent 
control options were evaluated at that time. During the development of 
the 2016 NSPS OOOOa rule, the EPA reviewed available information on 
control options for wet seal compressors and did not identify any new 
information to indicate that this has changed.
    For this review, the EPA also focused on these control options. 
BSER was evaluated for wet-seal centrifugal compressors at gathering 
and boosting stations (considered to be representative of emissions 
from centrifugal compressors at centralized production facilities) in 
the production segment, at natural gas processing plants, and at sites 
in the transmission and storage segment. During the development of the 
2012 NSPS OOOO and 2016 NSPS OOOOa rulemakings, our data indicated that 
there were no centrifugal compressors located at well sites. Since the 
2012 NSPS OOOO and 2016 NSPS OOOOa rulemakings, we have not received 
information that would change our understanding that there are no 
centrifugal compressors in use at well sites.
    However, as discussed in section XI.L (Centralized Production 
Facilities) of this preamble, the EPA believes the definition of ``well 
site'' in NSPS OOOOa may cause confusion regarding whether centrifugal 
compressors located at centralized production facilities are also 
exempt from the standards. The EPA is proposing a new definition for a 
``centralized production facility''. The EPA is proposing to define 
centralized production facilities separately from well sites because 
the number and size of equipment, particularly reciprocating and 
centrifugal compressors, is larger than standalone well sites which 
would not be included in the proposed definition of ``centralized 
production facilities''. This proposal is necessary in the context of 
centrifugal compressors to distinguish between these compressors at 
centralized production facilities where the EPA has determined that the 
standard should apply, and compressors at standalone well sites where 
the EPA has determined that the standard should not apply. In our 
current analysis, described below, we consider the centrifugal 
compressor gathering and boosting segment emission factor as being 
representative of centrifugal compressor emissions located at 
centralized production facilities. As such, the EPA is proposing that 
centrifugal compressors located at centralized production facilities 
would be subject to the standards in NSPS OOOOb and the EG in subpart 
OOOOc, but centrifugal compressors at well sites (standalone well 
sites) would not.
    In addition to the requirement to reduce methane and VOC emissions 
from each centrifugal compressor wet seal fluid degassing system by 
95.0 percent, the 2016 NSPS OOOOa requires compressor components to be 
monitored as fugitive emissions components and leaks found are to be 
repaired under the fugitive emissions monitoring requirements of 40 CFR 
60.5397a. The monitoring frequency depends on source (i.e., well sites, 
compressor stations) and sector segment. These fugitive emissions 
components were not considered part of the centrifugal compressor 
affected facility.
    Based on the EPA's review of NSPS OOOOa, we are proposing that BSER 
continues to be that methane and VOC

[[Page 63221]]

emissions be reduced from each centrifugal compressor wet seal fluid 
degassing system by 95.0 percent.
b. Description
    Centrifugal compressors use a rotating disk or impeller to increase 
the velocity of the natural gas where it is directed to a divergent 
duct section that converts the velocity energy to pressure energy. 
These compressors are primarily used for continuous, stationary 
transport of natural gas in the processing and transmission systems. 
Some centrifugal compressors use wet (meaning oil) seals around the 
rotating shaft to prevent natural gas from escaping where the 
compressor shaft exits the compressor casing. The wet seals use oil 
which is circulated at high pressure to form a barrier against 
compressed natural gas leakage. The circulated oil entrains and adsorbs 
some compressed natural gas that may be released to the atmosphere 
during the seal oil recirculation process. Off gassing of entrained 
natural gas from wet seal centrifugal compressors is not suitable for 
sale and is either released to the atmosphere, flared, or routed back 
to a process.
    Some centrifugal compressors utilize dry seal systems. Dry seal 
systems minimize leakage by using the opposing force created by 
hydrodynamic grooves and springs. The hydrodynamic grooves are etched 
into the surface of the rotating ring affixed to the compressor shaft. 
When the compressor is not rotating, the stationary ring in the seal 
housing is pressed against the rotating ring by springs. When the 
compressor shaft rotates at high speed, compressed natural gas has only 
one pathway to leak down the shaft, and that is between the rotating 
and stationary rings. This natural gas is pumped between the grooves in 
the rotating and stationary rings. The opposing force of high-pressure 
natural gas pumped between the rings and springs trying to push the 
rings together creates a very thin gap between the rings through which 
little natural gas can leak. While the compressor is operating, the 
rings are not in contact with each other and, therefore, do not wear or 
need lubrication. O-rings seal the stationary rings in the seal case. 
Historically, the EPA has considered dry seal centrifugal compressors 
to be inherently low-emitting and has never required control of 
emissions from dry seal compressors. The EPA has received 
feedback,\286\ however, that there are some wet seal compressor system 
designs that are also low emitting when compared to dry seal 
compressors and is soliciting comment on lower emitting wet seal 
compressor system designs and dry seal compressor emissions in this 
proposed action.
---------------------------------------------------------------------------

    \286\ Conference Call. Prepared by Tora Consulting. December 19, 
2018.
---------------------------------------------------------------------------

    The 2021 U.S. GHGI estimates over 166,700 metric tpy of methane 
emissions in 2019 from compressors from natural gas systems. For the 
natural gas processing and transmission segments, wet seal compressor 
methane emissions are estimated to be about 78,700 metric tons and dry 
seal compressor methane estimated emissions are estimated to be about 
88,000 metric tons.\287\ The wet seal and dry seal compressor methane 
emission estimates reflect the increasing prevalence of the use of dry 
seals over wet seals and emissions control requirements that require 
the control of emissions from wet seal compressors. The methane 
emissions from centrifugal compressors represent 3 percent of the total 
methane emissions from natural gas systems in the Oil and Natural Gas 
Industry sector.
---------------------------------------------------------------------------

    \287\ U.S. Environmental Protection Agency. Inventory of U.S. 
Greenhouse Gas Emissions and Sinks (1990-2019). Published in 2021. 
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2019.
---------------------------------------------------------------------------

c. Affected Facility
    For purposes of the NSPS, the centrifugal compressor affected 
facility is a single centrifugal compressor using wet seals. A 
centrifugal compressor located at a well site, or an adjacent well site 
and servicing more than one well site, is not an affected facility 
under the proposed rule for NSPS OOOOb. As discussed above, the EPA is 
proposing that the affected facility includes centrifugal compressors 
located at centralized production facilities and the affected facility 
exception for ``a well site, or an adjacent well site servicing more 
than one well site'' applies to standalone well sites and not 
centralized production facilities.
d. 2021 BSER Analysis
    The methodology we used for estimating emissions from compressors 
is consistent with the methodology developed for the 2012 NSPS OOOO 
BSER analysis, which was also used to support the 2016 NSPS OOOOa 
BSER.\288\ The wet-seal centrifugal compressor methane uncontrolled 
emission factors are based on the volumetric emission factors used for 
the GHGI, which were converted to a mass emission rate using a density 
of 41.63 pounds of methane per thousand cubic feet. The VOC emissions 
were calculated using the ratio of 0.278 pounds VOC per pound of 
methane for the production and processing segments, and 0.0277 pounds 
VOC per pound of methane for the transmission and storage segment. The 
resulting baseline uncontrolled emissions per centrifugal compressor 
are 157 tpy methane (43.5 tpy VOC) from wet-seal compressors at 
gathering and boosting sites, 211 tpy methane (58.7 tpy VOC) from wet-
seal compressors at natural gas processing plants, 157 tpy methane (4.3 
tpy VOC) from wet-seal compressors at transmission compressor stations, 
and 117 (3.24 tpy VOC) from wet-seal compressors at storage facilities. 
Since the emission factors for dry seal compressors are approximately 
lower than wet seal compressors,\289\ the EPA considered requiring dry 
seals as a replacement to wet seals as a control option in 2011. The 
EPA proposed dry seals as a replacement to wet seals to control VOC 
emissions at that time. Based on comments received on the proposal that 
dry seal compressors were not feasible in all instances based on costs 
and technical reasons, the EPA did not finalize the proposal that dry 
seal compressors represented BSER. Instead, the EPA separately 
evaluated the control options for wet seal compressors (77 FR 49499-
49500, 49523, August 16, 2012). In the 2015 NSPS OOOOa proposed rule, 
the EPA maintained that available information since the 2012 NSPS OOOO 
rule continued to show that dry seal compressors cannot be use in all 
circumstances. The EPA has not identified any new information since 
that time that indicates that dry seal compressors as a replacement for 
wet seal compressors is technically feasible in all circumstances. 
Thus, we did not evaluate the replacement of a wet seal system with a 
dry seal system as BSER for controlling emissions from wet seal systems 
for the NSPS OOOOb proposal.
---------------------------------------------------------------------------

    \288\ 2011 NSPS OOOO TSD, section 6.2.2; 2016 NSPS OOOOa TSD, 
section 7.2.2.
    \289\ 2011 NSPS OOOO TSD, Table 6-2, pg. 6-4; 2016 NSPS OOOOa 
TSD, Table 7-2, pg. 104.
---------------------------------------------------------------------------

    In addition to soliciting comment and information on lower-emitting 
wet seal compressor designs (that emit less than dry seal compressors), 
the EPA is soliciting information on dry seal compressor emissions. 
Feedback received (noted above) on lower emitting wet seal compressor 
designs included concern that lower emitting wet seal systems were 
being replaced by higher emitting (but still low emitting) dry seal 
systems because they were not subject to the NSPS. Given that the trend 
has been that wet seal compressor systems are increasingly being 
replaced by dry seal compressor systems, the EPA solicits comments on 
dry seal compressor emissions and whether/and

[[Page 63222]]

to what degree operational or malfunctioning conditions (e.g., low seal 
gas pressure, contamination of the seal gas, lack of supply of 
separation gas, mechanical failure) have the potential to impact 
methane and VOC emissions. The EPA also solicits comment on whether 
owners and operators implement standard operating procedures to 
identify and correct operational or malfunction conditions that have 
the potential to increase emissions from dry seal systems. Finally, the 
EPA solicits comments on whether we should consider evaluating BSER and 
developing NSPS standards for dry seal compressors.
    The control options to reduce emissions from centrifugal 
compressors evaluated include control techniques that reduce emissions 
from leaking of natural gas from wet seal compressors by capturing 
leaking gas and route it either to (1) a control device (combustion 
device), or (2) to the process. We evaluated the costs and impacts of 
both of these options.
    Combustion devices are commonly used in the Crude Oil and Natural 
Gas Industry to combust methane and VOC emission streams. Combustors 
are used to control VOC and methane emissions in many industrial 
settings, since the combustor can normally handle fluctuations in 
concentration, flow rate, heating value and inert species content.\290\ 
A combustion device generally achieves 95 percent reduction of methane 
and VOC when operated according to the manufacturer instructions. For 
this analysis, we assumed that the entrained natural gas from the seal 
oil that is removed in the degassing process would be directed to a 
combustion device that achieves a 95 percent reduction of methane and 
VOC emissions. This option was determined to be BSER under the 2011 
NSPS OOOO (77 FR 49490, August 16, 2012) and 2016 NSPS OOOOa rules. The 
combustion of the recovered gas creates secondary emissions of 
hydrocarbons (NOX, CO2, and CO emissions). 
Routing the captured gas from the centrifugal compressor wet seal 
degassing system to a combustion device has associated capital and 
operating costs.
---------------------------------------------------------------------------

    \290\ U.S. Environmental Protection Agency. AP 42, Fifth 
Edition, Volume I, Chapter 13.5 Industrial Flares. Office of Air 
Quality Planning & Standards. 1991.
---------------------------------------------------------------------------

    The capital and annual costs for the installation of a combustion 
device (an enclosed flare for the analysis) were calculated using the 
methodology in the EPA Control Cost Manual.\291\ The capital costs of a 
flare and the equipment (closed vent system) necessary to route 
emissions to the flare are based on costs from the 2011 NSPS OOOO TSD 
and 2016 NSPS OOOOa TSD. These costs were updated to 2019 dollars. The 
updated capital costs of $80,930 were annualized at 7 percent based on 
an equipment life of 10 years. The total annualized capital costs were 
estimated to be $11,520. The annual operating costs are also based on 
the 2011 NSPS OOOO TSD and 2016 NSPS OOOOa TSD. These costs were 
updated to 2019 dollars. The 2019 annual operating costs were estimated 
to be $117,160. The combined annualized capital and operating costs per 
compressor per year is an estimated $128,680. There is no cost savings 
estimated for this option because the recovered natural gas is 
combusted. The costs presented for gathering and boosting segment 
centrifugal compressors represent the estimated costs assumed for 
centrifugal compressors located at centralized production facilities.
---------------------------------------------------------------------------

    \291\ U.S. Environmental Protection Agency. OAQPS Control Cost 
Manual: Sixth Edition (EPA 452/B-02-001). Research Triangle Park, 
NC.
---------------------------------------------------------------------------

    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the cost effectiveness of 
routing emissions from a wet seal system to a new flare for methane 
emissions is $870 per ton of methane reduced for the transmission 
segment and gathering and boosting, $640 per ton of methane reduced for 
the processing segment, and $1,160 per ton of methane reduced for the 
storage segment. Using the multipollutant approach, where half the cost 
of control is assigned to the methane reduction and half to the VOC 
reduction, the cost effectiveness of routing emissions from a wet seal 
system to a new flare for methane emissions is $430 per ton of methane 
reduced for the transmission segment and gathering and boosting, $320 
per ton of methane reduced for the processing segment, and $580 per ton 
of methane reduced for the storage segment.
    Using the single-pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the cost effectiveness of 
routing emissions from a wet seal system to a new flare for VOC 
emissions is $3,100 per ton of VOC reduced for gathering and boosting, 
$2,300 per ton of VOC reduced for the processing segment, $31,200 per 
ton of VOC reduced for the transmission segment, and $41,800 per ton of 
VOC reduced for the storage segment. Using the multipollutant approach, 
where half the cost of control is assigned to the methane reduction and 
half to the VOC reduction, the cost effectiveness of routing emissions 
from a wet seal system to a new flare for VOC emissions is $1,600 per 
ton of VOC reduced for gathering and boosting, $1,200 per ton of VOC 
reduced for the processing segment, $15,600 per ton of VOC reduced for 
the transmission segment, and $20,900 per ton of VOC reduced for the 
storage segment.
    In addition to an owner or operator having the option to capture 
emissions and routing to a new combustion control device, a less costly 
option that may be available could be for owners and operators to 
capture and route emissions to a combustion control device installed 
for another source (e.g., a control device that is already on site to 
control emissions from another emissions source). The costs, which are 
provided in the NSPS OOOOb and EG TSD for this rulemaking, would be for 
the ductwork to capture the emissions and route them to the control 
device. The analysis assumes that the combustion control device on site 
achieves a 95 percent reduction in emissions of methane and VOC.
    Another option for reducing methane and VOC emissions from the 
compressor wet seal fluid degassing system is to route the captured 
emissions back to the compressor suction or fuel system, or other 
beneficial use (referred to collectively as routing to a process). 
Routing to a process would entail routing emissions via a closed vent 
system to any enclosed portion of a process unit (e.g., compressor or 
fuel gas system) where the emissions are predominantly recycled, 
consumed in the same manner as a material that fulfills the same 
function in the process, transformed by chemical reaction into 
materials that are not regulated materials, incorporated into a 
product, or recovered. Emissions that are routed to a process are 
assumed to result in the same or greater emission reductions as would 
have been achieved had the emissions been routed through a closed vent 
system to a combustion device.\292\ For purposes of this analysis, we 
assumed that routing methane and VOC emissions from a wet seal fluid 
degassing system to a process reduces VOC emissions greater than or 
equal to a combustion device (i.e., greater than or equal to 95 
percent). There are no secondary impacts with the option to control 
emissions from centrifugal wet seals by capturing gas and routing to 
the process.
---------------------------------------------------------------------------

    \292\ U.S. Environmental Protection Agency. Control Techniques 
Guidelines for the Oil and Natural Gas Industry. Office of Air 
Quality Planning and Standards, Sector Policies and Programs 
Division. October 2016. EPA-453/B-16-001. (2016 CTG). pgs. 5-19 to 
5-20.

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

[[Page 63223]]

    The capital cost of a system to route the seal oil degassing system 
to a process is estimated to be $26,210 ($2,019),\293\ The estimated 
costs include an intermediate pressure degassing drum, new piping, gas 
demister/filter, and a pressure regulator for the fuel line. The annual 
costs were estimated to be $2,880 (without savings) assuming a 15-year 
equipment life at 7 percent interest. Because the natural gas is not 
lost or combusted, the value of the natural gas represents a savings to 
owners and operators in the production (gathering and boosting) and 
processing segments. Savings were estimated using a natural gas price 
of $3.13 per Mcf, which resulted in annual savings of $27,000 per year 
at gathering and boosting stations and $36,400 per year at processing 
plants. The annual cost savings are much greater than the annual costs, 
which results in an overall savings when they are considered.
---------------------------------------------------------------------------

    \293\ 2011 NSPS OOOO TSD, pg. 114; 2016 CTG, pg. 5-20.
---------------------------------------------------------------------------

    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the cost effectiveness 
(without natural gas savings) of routing emissions from a wet seal 
system to a process for methane emissions is approximately $19 per ton 
of methane reduced for the transmission segment and gathering and 
boosting, $14 per ton of methane reduced for the processing segment, 
and $26 per ton of methane reduced for the storage segment. Using the 
multipollutant approach, where half the cost of control is assigned to 
the methane reduction and half to the VOC reduction, the cost 
effectiveness (without natural gas savings) of routing emissions from a 
wet seal system to a process for methane emissions is approximately $10 
per ton of methane reduced for the transmission segment and gathering 
and boosting, $7 per ton of methane reduced for the processing segment, 
and $13 per ton of methane reduced for the storage segment. As noted 
above, there is an overall net savings if the value of the natural gas 
recovered is considered.
    Using the single pollutant approach, where all the costs are 
assigned to the reduction of one pollutant, the cost effectiveness 
(without natural gas savings) of routing emissions from a wet seal 
system to a process for VOC emissions is approximately $70 per ton of 
VOC reduced for gathering and boosting, $50 per ton of VOC reduced for 
the processing segment, $700 per ton of VOC reduced for the 
transmission segment, and $940 per ton of VOC reduced for the storage 
segment. Using the multipollutant approach, where half the cost of 
control is assigned to the methane reduction and half to the VOC 
reduction, the cost effectiveness (without natural gas savings) of 
routing emissions from a wet seal system to a process for VOC emissions 
is approximately $35 per ton of VOC reduced for gathering and boosting, 
$26 per ton of VOC reduced for the processing segment, $350 per ton of 
VOC reduced for the transmission segment, and $470 per ton of VOC 
reduced for the storage segment. As noted above, there is an overall 
net savings if the value of the natural gas recovered is considered.
    The cost effectiveness of both options (routing emissions to a 
combustion device or to a process) are reasonable for methane for all 
of the evaluated segments, using both the single pollutant and 
multipollutant approaches. The cost effectiveness of routing emissions 
to a process are also reasonable for VOC for all of the evaluated 
segments, using both the single pollutant and multipollutant 
approaches. For routing emissions to a combustion device, the cost 
effectiveness is reasonable for the gathering and boosting and 
processing segments using the single pollutant and multipollutant 
approaches. Based on the consideration of the costs in relation to the 
emission reductions of both methane and VOC, the EPA finds that 
requiring emissions to be reduced from each centrifugal compressor 
using a wet seal by at least 95 percent (which can be achieved by 
either option) continues to be reasonable in the gathering and boosting 
(considered to be representative of emissions/costs from centrifugal 
compressors at centralized production facilities). processing, 
transmission and storage segments.
    The 2012 NSPS OOOO and the 2016 NSPS OOOOa require emissions be 
reduced from each centrifugal compressor wet seal fluid degassing 
system by at least 95.0 percent by routing emissions to a control 
device or to a process. States have generally adopted/incorporated this 
NSPS level of control (or a level of control that is substantially 
similar) in their State regulations for the control of emissions from 
centrifugal compressor sources using wet seals. Owners and operators 
have successfully met this standard for almost a decade. These facts 
further demonstrate the reasonableness of this level of control. In the 
discussion above, we reviewed two options to reduce emissions from wet 
seal compressors that are both current regulatory options under the 
2016 NSPS OOOOa: (1) Capturing leaking gas and route to a combustion 
device (flare), or (2) capturing leaking gas and route to the process. 
Under the 2016 NSPS OOOOa, the level of control determined based on 
BSER was that methane and VOC emissions be reduced from each 
centrifugal compressor wet seal fluid degassing system by 95 percent or 
greater. The EPA has not identified any other control options or any 
other Federal, State, or local requirements that would achieve a 
greater reduction in methane and VOC emissions from centrifugal 
compressor wet seal systems. Although capturing leaking gas and routing 
to the process has the advantage of both reducing emissions by at least 
95 percent or greater and capturing the natural gas (resulting in a 
natural gas savings), the EPA has received feedback in the development 
of the 2012 NSPS OOOO rule that this option may not be a viable option 
in situations where there may not be down-stream equipment capable of 
handling a low-pressure fuel source. During the development of the 2016 
NSPS OOOOa rule, the EPA reaffirmed that information since the 
development of the 2012 NSPS OOOO rule continues to show that capturing 
leaking gas and routing to the process cannot be used in all 
circumstances. No new information has been identified since the 
development of the 2016 NSPS OOOOa rule to indicate that capturing 
leaking gas and routing to the process can be achieved in all 
circumstances (80 FR 56619, September 18, 2015). Thus, by establishing 
a 95 percent methane and VOC emissions control level as BSER, an owner 
or operator has the option of routing emissions to a process where it 
is a viable option, or to a combustion device where routing to a 
process is not a viable option. If an owner or operator chooses to 
route to a process to meet the 95 percent level of control, there are 
no secondary impacts. If an owner or operator chooses to route to a 
combustion device to meet the 95 percent level of control, the 
combustion of the recovered gas creates secondary emissions of 
hydrocarbons (NOX, CO2, and CO emissions).
    The costs, emission reductions, and cost effectiveness values were 
presented above for collecting the wet seal compressor emissions and 
routing them to both a combustion device and to a process to achieve at 
least a 95 percent control. The EPA considers the cost effectiveness of 
both of these control options reasonable across all segments evaluated 
(i.e., the gathering and boosting portion of production, processing, 
transmission, storage) for the reduction of methane emissions under the 
single pollutant approach and multipollutant approach. As discussed

[[Page 63224]]

above, in our current analysis, we consider the centrifugal compressor 
gathering and boosting segment emission factor as being representative 
of centrifugal compressor emissions located at centralized production 
facilities. Thus, the cost analysis performed for the gathering and 
boosting segment represents the estimated costs of evaluated options 
for centrifugal compressors with wet seals located at centralized 
storage facilities.
    In light of the above, we determined that reducing methane and VOC 
emissions from each centrifugal compressor wet seal fluid degassing 
system by 95 percent or greater continues to represent BSER for NSPS 
OOOOb for this proposal. The affected facility based on EPA's review 
would continue be each wet seal compressor not located at a well site, 
or an adjacent well site and servicing more than one well site. As 
discussed above, the EPA is proposing a new definition for a 
``centralized production facility''. The EPA is proposing to define 
centralized production facilities separately from well sites because 
the number and size of equipment, particularly reciprocating and 
centrifugal compressors, is larger than standalone well sites which 
would not be included in the proposed definition of ``centralized 
production facilities''. Thus, the EPA is proposing that centrifugal 
compressors located at centralized production facilities would be 
subject to the standards in the NSPS in OOOOb, but centrifugal 
compressors at well sites (standalone well sites) would not.
2. EG OOOOc
    The EPA evaluated BSER for the control of methane from existing 
centrifugal compressors using wet seals (not located at a well site, or 
an adjacent well site and servicing more than one well site) 
(designated facilities) in all segments in the Crude Oil and Natural 
Gas source category covered by the proposed NSPS OOOOb and translated 
the degree of emission limitation achievable through application of the 
BSER into a proposed presumptive standard for these facilities that 
essentially mirrors the proposed NSPS OOOOb.
    First, based on the same criteria and reasoning as explained above, 
the EPA is proposing to define the designated facility in the context 
of existing centrifugal compressors using wet seals (not located at a 
well site, or an adjacent well site and servicing more than one well 
site) as those that commenced construction on or before November 15, 
2021. Based on information available to the EPA, we did not identify 
any factors specific to existing sources that would indicate that the 
EPA should alter this definition as applied to existing sources. Next, 
the EPA finds that the control measures evaluated for new sources for 
NSPS OOOOb are appropriate for consideration for existing sources under 
the EG OOOOc. The EPA finds no reason to evaluate different, or 
additional, control measures in the context of existing sources because 
the EPA is unaware of any control measures, or systems of emission 
reduction, for centrifugal compressors that could be used for existing 
sources but not for new sources. Next, the methane emission reductions 
expected to be achieved via application of the control measures 
identified above to new sources are also expected to be achieved by 
application of the same control measures to existing sources. The EPA 
finds no reason to believe that these calculations would differ for 
existing sources as compared to new sources because the EPA believes 
that the baseline emissions of an uncontrolled source are the same, or 
very similar, and the efficiency of the control measures are the same, 
or very similar, compared to the analysis above. This is also true with 
respect to the costs, non-air environmental impacts, energy impacts, 
and technical limitations discussed above for the control options 
identified.
    The EPA has not identified any costs associated with applying these 
controls at existing sources, such as retrofit costs, that would apply 
any differently than, or in addition to, those costs assessed above 
regarding application of the identified controls to new sources. The 
cost effectiveness values for the proposed presumptive standard of 
reducing methane emissions from each centrifugal compressor wet seal 
fluid degassing system by 95 percent or greater are based on the cost 
effectiveness of routing emissions from a wet seal system to a flare or 
to a process. The cost effectiveness of routing emissions from a wet 
seal system to a new flare for methane emissions is $870 per ton of 
methane reduced for the transmission segment and gathering and 
boosting, $640 per ton of methane reduced for the processing segment, 
and $1,160 per ton of methane reduced for the storage segment. The cost 
effectiveness (without natural gas savings) of routing emissions from a 
wet seal system to a process for methane emissions is approximately $19 
per ton of methane reduced for the transmission segment and gathering 
and boosting, $14 per ton of methane reduced for the processing 
segment, and $26 per ton of methane reduced for the storage segment.
    In summary, the EPA did not identify any factors specific to 
existing sources, as opposed to new sources, that would alter the 
analysis above for the proposed NSPS OOOOb as applied to the designated 
pollutant (methane) and the designated facilities (centrifugal 
compressors using wet seals). As a result, the proposed presumptive 
standard for existing centrifugal compressors using wet seals is as 
follows.
    For centrifugal compressors using wet seals in the gathering and 
boosting segment (including centrifugal compressors using wet seals 
located at centralized tank facilities), processing, and transmission 
and storage segments, the presumptive standard is to reduce methane 
emissions by at least 95 percent. An owner or operator can meet this 
presumptive standard by routing methane emissions to a control device 
or process that reduces emissions by at least 95 percent. As discussed 
previously, the EPA is proposing a new definition for a ``centralized 
production facility''. The EPA is proposing to define centralized 
production facilities separately from well sites because the number and 
size of equipment, particularly reciprocating and centrifugal 
compressors, is larger than standalone well sites which would not be 
included in the proposed definition of ``centralized production 
facilities''. Thus, the EPA is proposing that centrifugal compressors 
located at centralized production facilities would be subject to the 
standards in the EG in OOOOc, but centrifugal compressors at well sites 
(standalone well sites) would not.

G. Proposed Standards for Pneumatic Pumps

1. NSPS OOOOb
a. Background
    In the 2016 NSPS OOOOa, the EPA established GHG (in the form of 
limitations on methane emissions) and VOC standards for natural gas-
driven diaphragm pneumatic pumps located at well sites. This standard 
required that natural gas emissions be reduced by 95.0 percent by 
routing to an existing control device if: (1) A control device was 
onsite, (2) the control device could achieve a 95.0 percent reduction, 
and (3) it was technically feasible to route the emissions to the 
control device. The standard did not require the installation of a 
control device solely for the purpose of complying with the 95.0 
percent reduction for the emissions from pneumatic pumps. It also 
allowed

[[Page 63225]]

the option of routing emissions to a process. At natural gas processing 
plants, the EPA established a standard that required a natural gas 
emission rate of zero (i.e., that prohibited methane and VOC emissions 
from pneumatic pumps).
    As a result of the review of these requirements and the previous 
BSER determination, the EPA is proposing methane and VOC standards in 
NSPS OOOOb for natural gas-driven pneumatic pumps located in all 
segments of the source category. Specifically, the EPA is proposing 
that each natural gas driven pneumatic pump is an affected facility. 
The EPA is proposing that methane and VOC emissions from natural gas-
driven diaphragm and piston pumps at well sites and all other sites in 
the production segment be reduced by 95.0 percent or routed to a 
process, provided that there is an existing control device onsite or it 
is technically feasible to route the emissions to a process. For 
natural gas driven pneumatic pumps at natural gas transmission stations 
and natural gas storage facilities, the same requirement applies, but 
only to diaphragm pumps. The EPA is proposing to retain the technical 
infeasibility provisions of NSPS OOOOa for purposes of NSPS OOOOb. If 
there is a control device onsite,\294\ the owner or operator is not 
required to route emissions to that control device if it is not 
technically feasible to do so, even for new construction sites which 
the EPA had previously referred to as ``greenfield'' sites. The EPA is 
also proposing to retain in NSPS OOOOb the exception to the 95.0 
percent reduction requirement if there is a control device onsite that 
it is technically feasible to route to that cannot achieve that level 
of reduction but can achieve a lower level of reductions. In those 
situations, the emissions from the pump are still to be routed to the 
control device and controlled at the level that the device can achieve. 
The EPA is also proposing a prohibition on methane and VOC emissions 
from pneumatic pumps (diaphragm and piston pumps) at natural gas 
processing plants. While zero emissions pneumatic pumps would not 
technically be affected facilities because they are not driven by 
natural gas, owners and operators should maintain documentation if they 
would like to be able to demonstrate to permit writers or enforcement 
officials that there are no methane or VOC emissions from the pumps and 
that these pumps are not affected facilities subject to the rule.
---------------------------------------------------------------------------

    \294\ For the same reasons discussed in section X.B.2, the EPA 
is proposing that boilers and process heaters are not control 
devises for purposes of controlling emissions from pneumatic pumps.
---------------------------------------------------------------------------

    This BSER for reducing methane and VOC from pneumatic pumps are the 
same as those for the 2016 NSPS OOOOa, except that (1) the EPA 
determined that the NSPS OOOOa levels of control also represent BSER 
for diaphragm pumps at all sites in the production segment (including 
gathering and boosting stations), and for all transmission and storage 
sites, and (2) the EPA determined that the NSPS OOOOa levels of control 
also represent BSER for piston pumps (in addition to diaphragm pumps) 
in the production segment and at natural gas processing plants.
    As discussed below, a primary reason that the EPA is unable to 
conclude that requiring a natural gas emission rate of zero for 
production and transmission and storage facilities is BSER at this time 
is because proven technologies that eliminate natural gas emissions 
rely on electricity to function. In contrast to pneumatic controllers, 
our review of information that has become available since the 
promulgation of the 2016 NSPS OOOOa standards, including State-level 
regulations for pneumatic pumps, does not demonstrate that zero 
emission technology for pneumatic pumps would be feasible at sites that 
lack access to onsite power. The EPA is specifically soliciting 
comments on the possibility of subcategorizing production and natural 
gas transmission and storage sites into those sites that have access to 
onsite power and those that do not, and then determining BSER 
separately for each subcategory. Further, the EPA is soliciting comment 
on how, if at all, the proposed NSPS OOOOb standards for pneumatic 
controllers might factor into how the EPA ought to evaluate the 
possibility of requiring a natural gas emission rate of zero for 
pneumatic pumps in the production and transmission and storage 
segments. For example, if a site installs a solar-powered system to 
operate their controllers, then could that same system provide power to 
the pumps such that all pumps at the site could have zero emissions of 
natural gas?
b. Description
    A pneumatic pump is a positive displacement reciprocating unit 
generally used by the Oil and Natural Gas Industry for one of four 
purposes: (1) Hot oil circulation for heat tracing/freeze protection, 
(2) chemical injection, (3) moving bulk liquids, and (4) glycol 
circulation in dehydrators. There are two basic types of pneumatic 
pumps used in the Oil and Natural Gas Industry, diaphragm pumps and 
piston pumps. Pumps used for heat tracing/freeze protection circulate 
hot glycol or other heat-transfer fluids in tubing covered with 
insulation to prevent freezing in pipelines, vessels and tanks. These 
heat tracing/freeze protection pumps are usually diaphragm pumps. 
Chemical injection pumps are designed to inject precise amounts of 
chemical into a process stream to regulate operations of a plant and 
protect the equipment. Typical chemicals injected in an oil or gas 
field are biocides, demulsifiers, clarifiers, corrosion inhibitors, 
scale inhibitors, hydrate inhibitors, paraffin dewaxers, surfactants, 
oxygen scavengers, and H2S scavengers. These chemicals are 
normally injected at the wellhead and into gathering lines or at 
production separation facilities. Since the injection rates are 
typically small, the pumps are also small. They are often attached to 
barrels containing the chemical being injected. These chemical 
injection pumps are primarily piston pumps, although they can be small 
diaphragm pumps. Examples of the use of pneumatic pumps to transfer 
bulk liquids at oil and natural gas production sites include pumping 
motor oil or pumping out sumps. Pumps used for these purposes ae 
typically diaphragm pumps.
    Glycol dehydrator pumps recover energy from the high-pressure rich 
glycol/gas mixture leaving the absorber and use that energy to pump the 
low-pressure lean glycol back into the absorber. Glycol dehydrator 
pumps are controlled under the oil and gas NESHAPs (40 CFR part 63, 
subparts HH and HHH), are not included as affected facilities for the 
2016 NSPS OOOOa and were not included in the review for proposed NSPS 
OOOOb.
    Both diaphragm and piston pumps are positive displacement 
reciprocating pumps, meaning they use contracting and expanding 
cavities to move fluids. These pumps work by allowing a fluid (e.g., 
the heat transfer fluid, demulsifier, corrosion inhibitor, etc) to flow 
into an enclosed cavity from a low-pressure source, trapping the fluid, 
and then forcing it out into a high-pressure receiver by decreasing the 
volume of the cavity. The piston and diaphragm pumps have two major 
components, a driver side and a motive side, which operate in the same 
manner but with different reciprocating mechanisms. Pressurized gas 
provides energy to the driver side of the pump, which operates a piston 
or flexible diaphragm to draw fluid into the pump. The motive side of 
the pump delivers the energy to the fluid being moved in order to 
discharge

[[Page 63226]]

the fluid from the pump. The natural gas leaving the exhaust port of 
the pump is either directly discharged into the atmosphere or is 
recovered and used as a fuel gas or stripping gas.
    Diaphragm pumps work by flexing the diaphragm out of the 
displacement chamber, and piston pumps typically include plunger pumps 
with a large piston on the gas end and a smaller piston on the liquid 
end to enable a high discharge pressure with a varied but much lower 
pneumatic supply gas pressure.
    As noted above, energy is supplied to the driver side of the pump 
to operate the piston or diaphragm. Commonly, this energy is provided 
by pressurized gas. This gas can be compressed air, or ``instrument 
air,'' provided by an electrically powered air compressor. In many 
situations across all segments of this industry, electricity is not 
available, and this energy is provided by pressurized natural gas 
(i.e., ``natural gas-driven pneumatic pumps''). This energy can also be 
directly provided by electricity.
    Natural gas-driven pneumatic pumps emit methane and VOC as part of 
their normal operation. These emissions occur when the gas used in the 
pump stroke is exhausted to enable liquid filling of the liquid cavity 
of the pump. Emissions are a function of the amount of fluid pumped, 
the pressure of the pneumatic supply gas, the number of pressure ratios 
between the pneumatic supply gas pressure and the fluid discharge 
pressure, and the mechanical inefficiency of the pump.
    The 2021 U.S. GHGI estimates almost 215,000 metric tpy of methane 
emissions from pneumatic pumps in the oil and natural gas production 
segment in 2019. Specifically, this includes almost 113,000 metric tpy 
from natural gas production, 75,000 from petroleum production, and 
26,000 from gathering and boosting compressor stations. These emissions 
make up 5 percent of all methane emissions in the GHGI for the combined 
gas and oil production segment, and 2 percent of all methane emissions 
for gathering and boosting. The overall total, which represents 3 
percent of the total methane emissions from this industry, does not 
include emissions from the processing, transmission, and storage 
segments which the EPA is now proposing to regulate under NSPS OOOOb.
c. 2021 BSER Analysis
    BSER was evaluated for all segments of the industry. The 2015 NSPS 
OOOOa proposal included methane and VOC standards for pneumatic pumps 
in the production and transmission and storage segments. However, the 
EPA did not finalize regulations for pneumatic pumps at gathering and 
boosting stations in the final 2016 NSPS OOOOa due to lack of data on 
the prevalence of the use of pneumatic pumps at gathering and boosting 
stations. Since that time, GHGRP subpart W has required that emissions 
from natural gas-driven pneumatic pumps be reported from gathering and 
boosting stations. As reported above, the 2021 GHGI estimates over 
26,000 metric tpy of methane emissions from these pumps in the 
gathering and boosting segment in 2019. Similarly, the EPA did not 
include pneumatic pumps in the transmission and storage segment in the 
final 2016 NSPS OOOOa because we did not have a reliable source of 
information indicating the prevalence of pneumatic pumps or their 
emission rates in the transmission and storage segment. While the GHGI 
does not include emissions from pneumatic pumps in the transmission and 
storage segment, and the GHGRP does not require the reporting of 
emissions from these pumps in this segment, State rules (notably the 
California rule and the proposed New Mexico rule) do include 
requirements for natural gas driven pneumatic pumps at transmission and 
storage facilities. The EPA is soliciting comment on whether natural 
gas driven pneumatic pumps are used in the natural gas transmission and 
storage segment and to what extent.
    In 2015, the EPA identified several options for reducing methane 
and VOC emissions from natural gas-driven pumps in the production and 
natural gas transmission and storage segments: Replace natural gas-
driven pumps with instrument air pumps, replace natural gas-driven 
pumps with solar-powered direct current pumps (solar pumps), replace 
natural gas-driven pumps with electric pumps, route natural gas-driven 
pump emissions to a control device, and route natural gas-driven pump 
emissions to a process. The only option identified in 2015 and analyzed 
at natural gas processing plants was the use of instrument air. The EPA 
re-evaluated that information as well as new information including 
updated GHGI and GHGRP information, as well as information from more 
recent State regulations. No additional options were identified at this 
time. Therefore, for this analysis for the NSPS, the EPA re-evaluated 
these options as BSER. In the discussion below, the options to require 
technology that would eliminate methane and VOC emissions by requiring 
the use of a non-natural gas driven pumps are discussed, followed by a 
discussion of routing natural gas driven pumps to a control device.
    With the exception of the evaluation of instrument air systems, the 
BSER analysis for pneumatic pumps was conducted on an individual pump 
basis. Due to the differences in the level of emissions, we conducted 
the BSER analysis separately for natural gas-driven diaphragm pneumatic 
pumps and natural gas-driven piston pneumatic pumps for the production 
and transmission and storage segments. The emission factor for 
diaphragm pneumatic pumps is 3.46 tpy of methane, while it is only 0.38 
tpy of methane for piston pumps. The corresponding VOC emission factors 
are 0.96 tpy for the production segment and 0.096 tpy for the 
transmission and storage segment for diaphragm pumps, and 0.11 and 0.01 
tpy for piston pumps, for production and transmission and storage 
segment, respectively.
    For instrument air systems, the BSER analysis was conducted using 
model plants that included combinations of diaphragm and piston pumps. 
For example, the smallest model plant included two diaphragm pumps and 
two piston pumps. Therefore, the cost effectiveness calculated for 
these instrument air systems represents the cost to eliminate emissions 
from both types of pumps. Since instrument air was the only option 
evaluated for natural gas processing plants, the BSER determination was 
made for all pumps at the plants (as opposed to separate determinations 
for diaphragm and piston pumps).
Zero Emissions Options
    For this analysis, we first evaluated the options that would 
eliminate methane and VOC emissions from pneumatic pumps, specifically 
instrument/compressed air systems, electric pumps, and solar-powered 
pumps.
    Instrument air systems require a compressor, power source, 
dehydrator, and volume tank. No alterations are needed to the pump 
itself to convert from using natural gas to instrument air. However, 
they can only be utilized in locations with sufficient electrical 
power. Instrument air systems are more economical and, therefore, more 
common at facilities with a high concentration of pneumatic devices and 
where an operator can ensure the system is properly functioning. 
Electric pumps provide the same functionality as gas-driven pumps and 
are only restricted by the availability of a source of electricity.
    Solar-powered pumps are a type of electric pump, except that the 
power is

[[Page 63227]]

provided by solar-charged direct current (DC). Solar-powered pumps can 
be used at remote sites where a source of electricity is not available, 
and they have been shown to be able to handle a range of throughputs up 
to 100 gallons per day with maximum injection pressure around 3,000 
pounds per square inch gauge (psig).
    Production and Transmission and Storage Segments. For the 
production and transmission and storage segments, we evaluated the 
costs and impacts of these ``zero-emissions'' options (See Chapter 9 of 
the NSPS OOOOb and EG TSD for this rulemaking). We found that the cost-
effectiveness of these options, for both diaphragm and piston pumps, 
were generally within the ranges that the EPA considers reasonable. 
However, for instrument air systems and electric pumps, our analysis 
assumes that electricity is available onsite. As noted above, in 2015, 
the EPA determined that a zero-emission standard for pumps in the 
production and transmission and storage segments was infeasible because 
(1) electricity is not available at all sites and (2) solar pumps are 
not technically feasible in all situations for which piston pumps and 
diaphragm pumps are needed. 80 FR 56625-56626. While we specifically 
requested comment on this determination in 2015, nothing was submitted 
at that time that caused a reversal in this decision. At this time, we 
are unclear as to whether these limitations have been overcome and 
whether zero-emission pneumatic pumps are technically feasible for all 
pneumatic pumps throughout the production and transmission and storage 
segments. Therefore, at this time, we are unable to conclude that this 
zero-emission option represents BSER in this proposal, but we are 
soliciting comment on this issue to better understand whether a zero-
emission option is now technically feasible.
    As explained in Section XII.C.1.e, the EPA believes that similar 
previously identified technical limitations have been overcome in the 
context of pneumatic controllers. Further, a few States do prohibit 
emissions from pneumatic pumps throughout the Crude Oil and Natural Gas 
Industry. California prohibits the venting of natural gas to the 
atmosphere from pneumatic pumps through the use of compressed air or 
electricity, or by collecting all potentially vented natural gas with 
the use of a vapor collection system that undergoes periodic leak 
detection and repair. While California requires this, the fact that 
other States (e.g., Colorado, Wyoming) do not require zero emissions 
from pneumatic pumps at all locations leads us to be uncertain as to 
whether it is technically feasible at this time. Canadian Provinces 
also regulate emissions from natural gas-driven pneumatic pumps. In 
British Columbia, pneumatic pumps installed after January 1, 2021, must 
not emit natural gas, and in Alberta, vent gas from pneumatic pumps 
installed after January 2, 2022, must be prevented. In addition, New 
Mexico has proposed a regulation that requires zero-emitting pumps, but 
only at production and transmission and storage sites that have access 
to electricity.
    The EPA is soliciting comment on the basis for our proposed 
determination: That because electricity is not available at all sites 
and that there are applications at these sites where solar-powered 
pumps may not be feasible the Agency is uncertain as to whether the 
zero-emission options represent BSER. Also, as noted above, we are 
soliciting comment on an approach where the EPA would propose to 
subcategorize pneumatic pumps located in the production and 
transmission and storage sites based on availability of electricity and 
develop separate standards for each subcategory.
    Natural gas processing plants. Natural gas processing plants are 
known to have a source of electrical power. Therefore, instrument air 
and electric pumps are technically feasible options at these 
facilities.
    As the next step in the BSER determination, we evaluated capital 
and annual costs of compressed air systems for the natural gas 
processing plants. While electric pumps are an option at natural gas 
processing plants, we assumed that natural gas processing plants will 
elect to always use instrument air and an impacts analysis for electric 
pumps was not conducted.
    The capital costs for an instrument air system were estimated to 
range from $4,500 to $39,500. The annual costs include the capital 
recovery cost (calculated at a 7 percent interest rate for 10 years), 
labor costs for operations and maintenance, and electricity costs. 
These are estimated to range from $11,300 to $81,350. Because gas 
emissions are avoided as compared to the use of natural gas-driven 
pumps, the use of an instrument air system will have natural gas 
savings realized from the gas not released. The EPA estimates that each 
diaphragm pump replaced will save 201 Mcf per year of natural gas from 
being emitted and each piston pump will save of 22 Mcf per year in the 
processing segment. The estimated value of the natural gas saved, based 
on $3.13 per Mcf, would range from $1,400 to $35,000 per year per 
plant. The annual costs, including these savings, ranges from $9,900 to 
$46,500. More information on this cost analysis is available in the 
NSPS OOOOb and EG TSD for this proposal.
    The resulting cost effectiveness, under the single pollutant 
approach where all the costs are assigned to the reduction of one 
pollutant, for the application of instrument air to achieve a 100 
percent emission reduction at natural gas processing plants ranges from 
$420 to $1,470 per ton of methane eliminated. For VOC, these cost 
effectiveness values ranged from $1,520 to $5,290 per ton of VOC 
eliminated. Considering savings, these cost effectiveness values range 
from $240 to $1,300 per ton of methane eliminated and $870 to $4,600 
per ton of VOC eliminated. Under the multipollutant approach where half 
the cost of control is assigned to the methane reduction and half to 
the VOC reduction, the cost effectiveness ranges from $210 to $730 per 
ton of methane eliminated and $760 to $2,640 per ton of VOC eliminated. 
Considering savings, the cost effectiveness values range from $120 to 
$650 per ton of methane eliminated and from $440 to $2,320 per ton of 
VOC eliminated. These values are well within the range of what the EPA 
considers to be reasonable for methane and VOC using both the single 
pollutant and multipollutant approaches. As discussed above, the 
evaluation for instrument air systems is based on a combination of 
diaphragm and piston pumps. Therefore, this determination of 
reasonableness applies to both types of pumps at natural gas processing 
plants.
    The 2016 NSPS OOOOa requires a natural gas emission rate of zero 
for pneumatic pumps at natural gas processing plants. Natural gas 
processing plants have successfully met this standard. Further, as 
discussed above several State agencies have rules that include this 
zero-emission requirement. This is a demonstration of the 
reasonableness of a natural gas emission rate of zero for pneumatic 
pumps at natural gas processing plants.
    Secondary impacts from the use of instrument air systems are 
indirect, variable, and dependent on the electrical supply used to 
power the compressor. These impacts are expected to be minimal, and no 
other secondary impacts are expected.
    In light of the above, we find that the BSER for reducing methane 
and VOC emissions from natural gas-driven piston and diaphragm pumps at 
gas processing plants is a natural gas emission rate of zero. This 
option results in a 100 percent reduction of emissions for both methane 
and VOC. Therefore, for NSPS OOOOb, we are

[[Page 63228]]

proposing to require a natural gas emission rate of zero for all 
pneumatic pumps at natural gas processing plants.
Routing to a Control Device or VRU Options
    Above we stated our determination that the EPA is unable to 
conclude that this zero-emission option represents BSER in this 
proposal for pumps in the production and transmission and storage 
segments. Therefore, we evaluated the use of control devices to reduce 
methane and VOC emissions. This BSER analysis was conducted on an 
individual pump basis and diaphragm and piston pumps were evaluated 
separately.
    Combustors (e.g., enclosed combustion devices, thermal oxidizers 
and flares that use a high-temperature oxidation process) can be used 
to control emissions from natural gas-driven pumps. Combustors are used 
to control VOCs in many industrial settings, since the combustor can 
normally handle fluctuations in concentration, flow rate, heating 
value, and inert species content. The types of combustors installed in 
the Crude Oil and Natural Gas Industry can achieve at least a 95 
percent control efficiency on a continuous basis. It is noted that 
combustion devices can be designed to meet 98 percent control 
efficiencies, and can control, on average, emissions by 98 percent or 
more in practice when properly operated. However, combustion devices 
that are designed to meet a 98 percent control efficiency may not 
continuously meet this efficiency in practice in the oil and gas 
industry due to factors such as variability of field conditions.
    A related option for controlling emissions from pneumatic pumps is 
to route vapors from the pump to a process, such as back to the inlet 
line of a separator, to a sales gas line, or to some other line 
carrying hydrocarbon fluids for beneficial use, such as use as a fuel. 
Use of a VRU has the potential to reduce the VOC and methane emissions 
from natural gas-driven pneumatic pumps by 100 percent if all vapor is 
recovered. However, the effectiveness of the gas capture system and 
downtime for maintenance would reduce capture efficiency and therefore, 
we estimate that routing emissions from a natural gas-driven pump to a 
VRU and to a process can reduce the gas emitted by approximately 95 
percent, while at the same time, capturing the gas for beneficial use.
    Based on a 95 percent reduction, the reduction in emissions in the 
production segment would be 3.29 tpy of methane and 0.91 tpy of VOC per 
diaphragm pump, and 0.36 tpy methane and 0.10 tpy VOC per piston pump. 
In the transmission and storage segment, the reduction in emissions 
would be 3.29 tpy of methane and 0.09 tpy of VOC per diaphragm pump, 
and 0.36 tpy of methane and 0.01 ton per year of VOC per piston pump.
    Installation of a new combustion device or VRU. Costs for the 
installation of a new combustion device and a new VRU were evaluated. 
Installing a new combustion device has associated capital costs and 
operating costs. Based on the analysis conducted for the 2012 NSPS for 
a combustion device to control emissions from storage vessels, the 
capital cost for installing a new combustion device was $32,300 in 2008 
dollars. We updated this to $38,500 to reflect 2019 dollars. Based on 
the life expectancy for a combustion device at 10 years, we estimate 
the annualized capital cost of installing a new combustion device to be 
$5,500 in 2019 dollars, using a 7 percent discount rate. The 2016 NSPS 
OOOOa TSD indicates the annual operating costs associated with a new 
combustion device were $17,000 in 2012 dollars, which we updated to 
$19,100 in 2019 dollars. Therefore, the total annual costs for a new 
combustion device are $24,600. Because the gas captured is combusted 
there are no gas savings associated with the use of a combustion 
device.
    Installing a new VRU would also have both capital costs and 
maintenance costs. We based the costs of a VRU on the analysis 
conducted for the 2012 NSPS for control of emissions from storage 
vessels, which is representative of the costs that would be incurred 
for a VRU used to reduce emissions from natural gas-driven pneumatic 
pumps. The capital cost and installation costs for a new VRU are 
estimated to be $116,900 (in 2019 dollars) and the annual operation and 
maintenance costs estimated to be $11,200 (in 2019 dollars). The total 
annualized cost of a new VRU is estimated to be $27,800, including the 
operation and maintenance cost and the annualized capital costs based 
on a 7 percent discount rate and 10-year equipment life.
    Because there is potential for beneficial use of gas recovered 
through the VRU, the savings that would be realized for 95 percent of 
the gas that would have emitted and lost were estimated. The gas saved 
would equate to 191 Mcf per year from a diaphragm pump and 21 Mcf per 
year from a piston pump. This results in estimated annual savings of 
$600 per diaphragm pump and $65 per piston pump in the production 
segment. The resulting annual costs, considering these savings, are 
$27,200 per diaphragm pump and $27,700 per piston pump in the 
production segment. Transmission and storage facilities do not own the 
natural gas; therefore, savings from reducing the amount of natural gas 
emitted/lost was not applied for this segment. More information on 
these cost analyses is available in the NSPS OOOOb and EG TSD for this 
proposal.
    The resulting cost effectiveness estimates for application of a new 
control device to reduce emissions from natural gas-driven pumps in the 
production segment by 95 percent, or the use of a VRU to route 
emissions back to a process, are discussed below under both the single 
pollutant approach, where all the costs are assigned to the reduction 
of one pollutant, and the multipollutant approach, where half the cost 
of control is assigned to the methane reduction and half to the VOC 
reduction. The results are presented separately for diaphragm and 
piston pumps. These values assume that the control device or VRU is 
installed solely for the purpose of controlling the emissions from a 
single natural gas-driven pneumatic pump, and only the emission 
reductions from a single pump are considered.
    For diaphragm pumps in the production segment using the single 
pollutant approach, the cost effectiveness is estimated to be $7,500 
per ton of methane reduced using a new combustion device, and $8,500 
using a new VRU ($8,300 with savings). For VOC, these cost 
effectiveness values are $26,900 per ton of VOC reduced using a new 
combustion device, and $30,400 using a new VRU ($29,800 with savings). 
These values are outside of the range considered reasonable by the EPA 
for both methane and VOC.
    For diaphragm pumps in the production segment using the 
multipollutant approach, the cost effectiveness is estimated to be 
$3,750 per ton of methane reduced using a new combustion device, and 
$4,250 using a new VRU ($4,150 with savings). For VOC, these cost 
effectiveness values are $13,450 per ton of VOC reduced using a new 
combustion device, and $15,200 using a new VRU ($14,900 with savings). 
These values are outside of the range considered reasonable by the EPA 
for both methane and VOC.
    For piston pumps in the production segment using the single 
pollutant approach, the cost effectiveness is estimated to be $68,100 
per ton of methane reduced using a combustion device, and $77,000 using 
a VRU ($76,800 with savings). For VOC, these cost effectiveness values 
are $244,800

[[Page 63229]]

per ton of VOC reduced using a combustion device, and $277,000 using a 
VRU ($276,400 with savings). These values are outside of the range 
considered reasonable by the EPA for both methane and VOC.
    For piston pumps in the production segment using the multipollutant 
approach, the cost effectiveness is estimated to be $34,000 per ton of 
methane reduced using a combustion device, and $38,500 using a VRU 
($38,400 with savings). For VOC, these cost effectiveness values are 
$122,400 per ton of VOC reduced using a combustion device, and $138,500 
using a VRU ($138,200 with savings). These values are outside of the 
range considered reasonable by the EPA for both methane and VOC.
    For diaphragm pumps in the transmission and storage segment using 
the single pollutant approach, the cost effectiveness is estimated to 
be $7,400 per ton of methane reduced using a new combustion device, and 
$8,500 using a new VRU. For VOC, these cost effectiveness values are 
$270,000 per ton of VOC reduced using a new combustion device, and 
$305,000 using a new VRU. These values are outside of the range 
considered reasonable by the EPA for both methane and VOC.
    For diaphragm pumps in the transmission and storage segment using 
the multipollutant approach, the cost effectiveness is estimated to be 
$3,700 per ton of methane reduced using a new combustion device, and 
$4,200 using a new VRU. For VOC, these cost effectiveness values are 
$135,000 per ton of VOC reduced using a new combustion device, and 
$152,600 using a new VRU. These values are outside of the range 
considered reasonable by the EPA for both methane and VOC.
    For piston pumps in the transmission and storage segment using the 
single pollutant approach, the cost effectiveness is estimated to be 
$68,000 per ton of methane reduced using a combustion device, and 
$77,000 using a VRU. For VOC, these cost effectiveness values are $2.5 
million per ton of VOC reduced using a combustion device, and $2.8 
million using a VRU. These values are outside of the range considered 
reasonable by the EPA for both methane and VOC.
    For piston pumps in the transmission and storage segment using the 
multipollutant approach, the cost effectiveness is estimated to be 
$34,000 per ton of methane reduced using a combustion device, and 
$38,500 using a VRU. For VOC, these cost effectiveness values are $1.2 
million per ton of VOC reduced using a combustion device, and $1.4 
million using a VRU. These values are outside of the range considered 
reasonable by the EPA for both methane and VOC.
    For diaphragm pumps, we do not consider the costs to be reasonable 
to install a new control device, or a new VRU to route the emissions to 
a process, for the production and transmission and storage segments for 
methane or VOC emission reduction using either the single pollutant or 
multipollutant approach. Similarly, for piston pumps, we do not 
consider the costs to be reasonable under any scenario. Therefore, we 
are unable to conclude that requiring the installation of a new control 
device, or the installation of a new VRU to route emissions to a 
process, to achieve 95 percent reduction of methane and VOC emissions 
from natural gas-driven pumps for the production or transmission 
segments represents BSER in this proposal.
    Routing to an existing combustion device or VRU. In addition to 
evaluating the installation of a new control device or new VRU 
installed solely for the purpose of reducing the emissions from a 
single natural gas-driven pneumatic pump, we evaluated the option of 
routing the emissions from natural gas-driven pneumatic pumps to an 
existing control device to achieve a 95 percent reduction in methane 
and VOC emissions or routing the emissions to an existing VRU and to a 
process. The emission reduction for this option would be the same as 
discussed above for a new control device achieving 95 percent control, 
that is 3.29 tpy of methane and 0.91 tpy of VOC per diaphragm pump, and 
0.36 tpy methane and 0.10 tpy VOC per piston pump in the production 
segment and 3.29 tpy of methane and 0.09 tpy of VOC per diaphragm pump, 
and 0.36 tpy of methane and 0.01 ton per year of VOC per piston pump in 
the transmission and storage segment. The resulting cost effectiveness 
estimates for use of an existing control device to reduce emissions 
from natural gas-driven pumps in the production segment by 95 percent, 
or the use of an existing VRU to route emissions to a process, are 
discussed below under both the single pollutant approach, where all the 
costs are assigned to the reduction of one pollutant, and the 
multipollutant approach, where half the cost of control is assigned to 
the methane reduction and half to the VOC reduction. The results are 
presented separately for diaphragm and piston pumps.
    We estimated the costs for routing emissions to an existing control 
device or VRU based on the average of the cost presented in the 2015 
proposed NSPS OOOOa and the costs presented by two commenters to the 
proposal,\295\ as documented in the 2016 NSPS OOOOa TSD. This yielded a 
capital cost estimate of $6,100 in 2019 dollars, for an annualized cost 
of $900 in 2019 dollars, using the 7 percent discount rate and 10-year 
equipment life. In the 2016 NSPS OOOOa TSD the EPA assumed there were 
no incremental operating costs for routing to an existing control 
device or VRU, so the total annual costs consist only of the $900 
capital recovery cost. This assumption is maintained for this analysis. 
The same savings discussed above for the gas that is recovered by a VRU 
would be realized when routing to an existing VRU and to a process. 
These savings are $600 per year per diaphragm pump and $65 per year per 
piston pump in the production segment. The resulting annual costs for 
routing to an existing VRU and to process, considering these savings, 
are $270 per diaphragm pump and $800 per piston pump in the production 
segment. As noted above, transmission and storage facilities do not own 
the natural gas; therefore, savings from reducing the amount of natural 
gas emitted/lost was not applied for this segment.
---------------------------------------------------------------------------

    \295\ EPA-HQ-OAR-2010-0505-6884-A1 and EPA-HQ-OAR-2010-0505-
6881.
---------------------------------------------------------------------------

    For diaphragm pumps in the production segment using the single 
pollutant approach, the cost effectiveness is estimated to be $260 per 
ton of methane reduced using an existing combustion device, and $260 
per ton of methane using an existing VRU ($80 with savings). For VOC, 
these cost effectiveness values are $950 per ton of VOC reduced using 
an existing combustion device, and $950 using an existing VRU ($300 
with savings). For diaphragm pumps in the production segment using the 
multipollutant approach, the cost effectiveness is estimated to be $130 
per ton of methane reduced using an existing combustion device, and 
$130 using an existing VRU ($40 with savings). For VOC, these cost 
effectiveness values are $475 per ton of VOC reduced using an existing 
combustion device, and $475 using an existing VRU ($150 with savings). 
These values are well within the range of what the EPA considers to be 
reasonable for methane and VOC using both the single pollutant and 
multipollutant approaches.
    For diaphragm pumps in the transmission and storage segment using 
the single pollutant approach, the cost effectiveness is estimated to 
be $260 per ton of methane reduced using an existing combustion device, 
and $260 using an existing VRU. For VOC, these

[[Page 63230]]

cost effectiveness values are $9,500 per ton of VOC reduced using an 
existing combustion device, and $9,500 using an existing VRU. For 
diaphragm pumps in the transmission and storage segment using the 
multipollutant approach, the cost effectiveness is estimated to be $130 
per ton of methane reduced using an existing combustion device, and 
$130 using an existing VRU. For VOC, these cost effectiveness values 
are $4,800 per ton of VOC reduced using an existing combustion device, 
and $4,800 using an existing VRU. These values are within the range of 
what the EPA considers to be reasonable.
    The 2016 NSPS OOOOa requires that emissions from natural gas driven 
pneumatic pumps at well sites achieve a 95 percent reduction in methane 
and VOC emissions by routing them to a control device if an existing 
control device is on site. Owners and operators at well sites have 
successfully met this standard. Further, several State agencies (e.g., 
California, proposed in New Mexico) have rules that include this 
requirement, and have extended the requirement to sites throughout the 
production segment as well as the transmission and storage segment. 
These factors considered together demonstrate the reasonableness of a 
requirement that emissions from natural gas driven pneumatic pumps at 
sites without access to electricity achieve a 95 percent reduction in 
methane and VOC emissions by routing them to a control device, provided 
that an existing control device is on site.
    There are secondary impacts from the use of a combustion device to 
control emissions routed from natural gas-driven diaphragm pumps. The 
combustion of the recovered natural gas creates secondary emissions of 
hydrocarbons, NOX, CO2, and CO. The EPA considers 
the magnitude of these emissions to be reasonable given the significant 
reduction in methane and VOC emissions that the control would achieve. 
Details of these impacts are provided in the NSPS OOOOb and EG TSD for 
this rulemaking. There are no other wastes created or wastewater 
generated. The secondary impacts from use of a VRU are indirect, 
variable, and dependent on the electrical supply used to power the VRU. 
No other secondary impacts are expected.
    In light of the above, we find that the BSER for reducing methane 
and VOC emissions from natural gas-driven diaphragm pumps in the 
production and transmission and storage segments is to route the 
emissions to an existing control device that achieves 95 percent 
control of methane and VOC, or to route the emissions to an existing 
VRU and to a process. We are, therefore, proposing to include this 
requirement in NSPS OOOOb.
    For piston pumps in the production segment using the single 
pollutant approach, the cost effectiveness is estimated to be $2,400 
per ton of methane reduced using a combustion device, and $2,400 using 
a VRU ($2,200 with savings). For VOC, these cost effectiveness values 
are $8,700 per ton of VOC reduced using a combustion device, and $8,700 
using a VRU ($8,000 with savings).
    For piston pumps in the production segment using the multipollutant 
approach, the cost effectiveness is estimated to be $1,200 per ton of 
methane reduced using a combustion device, and $1,200 using a VRU 
($1,100 with savings). For VOC, these cost effectiveness values are 
$4,350 per ton of VOC reduced using a combustion device, and $4,350 
using a VRU ($4,000 with savings).
    For piston pumps in the production segment, we do not consider the 
costs to route emissions from a natural gas-driven pneumatic pump to an 
existing control device to achieve 95 percent reduction, or to route to 
an existing VRU and to a process, to be reasonable for methane or VOC 
using the single pollutant approach. However, the methane and VOC cost 
effectiveness using the multipollutant method is within the range that 
the EPA considers reasonable.
    There are secondary impacts from the use of a combustion device to 
control emissions routed from natural gas-driven piston pumps. These 
impacts are the same as discussed above for diaphragm pumps.
    In light of the above, we find that the BSER for reducing methane 
and VOC emissions from natural gas-driven piston pumps in the 
production and transmission and storage segments is to route the 
emissions to an existing control device that achieves 95 percent 
control of methane and VOC, or to route the emissions to an existing 
VRU and to a process. We are, therefore, proposing to include this 
requirement for piston pumps in NSPS OOOOb.
    The EPA notes that State rules for concerning natural gas-driven 
piston pumps emissions control requirements differ. For example, 
California specifically includes both diaphragm and piston pumps in the 
definition of pneumatic pumps, while Colorado specifically excludes 
piston pumps from control requirements. At this time, the EPA is unable 
to fully understand the basis for the piston pump State control 
requirement differences based on the background information for these 
State rules.
    We are specifically seeking comment on the emissions factors used 
to estimate the baseline emissions from pneumatic pumps, which are from 
a 1996 EPA/GRI study.\296\ The EPA is interested in more recent 
information regarding emissions from pneumatic pumps.
---------------------------------------------------------------------------

    \296\ Gas Research Institute (GRI)/U.S. Environmental Protection 
Agency. 1996d. Research and Development, Methane Emissions from the 
Natural Gas Industry, Volume 13: Chemical Injection Pumps. June 1996 
(EPA-600/R-96-080m).
---------------------------------------------------------------------------

    For piston pumps in the transmission and storage segment using the 
single pollutant approach, the cost effectiveness is estimated to be 
$2,400 per ton of methane reduced using a combustion device, and $2,400 
using a VRU. For VOC, these cost effectiveness values are $87,000 per 
ton of VOC reduced using a combustion device, and $87,000 using a VRU.
    For piston pumps in the transmission and storage segment using the 
multipollutant approach, the cost effectiveness is estimated to be 
$1,200 per ton of methane reduced using a combustion device, and $1,200 
using a VRU. For VOC, these cost effectiveness values are $43,500 per 
ton of VOC reduced using a combustion device, and $43,500 using a VRU.
    For piston pumps in the transmission and storage segment, we do not 
consider the costs to be reasonable to route emissions from a natural 
gas-driven pneumatic pump to an existing control device, or to route to 
an existing VRU and to a process, for either methane or VOC under the 
single pollutant approach. Further, we do not find that the cost 
effectiveness for both methane and VOC to be reasonable under the 
multipollutant approach. Therefore, we are unable to conclude that 
requiring the routing of emissions from natural gas-driven piston pumps 
in the transmission and storage segment to an existing control device 
to achieve 95 percent reduction of methane and VOC emissions, or the 
routing of emissions to a VRU and to a process, represents BSER for 
NSPS OOOOb in this proposal.
2. EG OOOOc
    The EPA evaluated BSER for the control of methane from existing 
pneumatic pumps (designated facilities) in all segments in the Crude 
Oil and Natural Gas source category covered by the proposed NSPS OOOOb 
and translated the degree of emission limitation achievable through 
application of the BSER into a proposed presumptive standard for these 
facilities

[[Page 63231]]

that mirrors the proposed NSPS OOOOb, with the exception of the BSER 
conclusion regarding piston pumps in the production segment.
    First, based on the same criteria and reasoning explained above the 
EPA is proposing to define the designated facility in the context of 
existing pneumatic pumps as those that commenced construction on or 
before November 15, 2021. Based on information available to the EPA, we 
did not identify any factors specific to existing sources that would 
indicate that the EPA should alter this definition as applied to 
existing sources.
    The EPA finds that the controls evaluated for new sources for NSPS 
OOOOb are appropriate for consideration for existing sources under the 
EG OOOOc. The EPA finds no reason to evaluate different, or additional, 
control measures in the context of existing sources because the EPA is 
unaware of any control measures, or systems of emission reduction, for 
pneumatic pumps that could be used for existing sources but not for new 
sources. Next, the methane emission reductions expected to be achieved 
via application of the control measures identified above to new sources 
are also expected to be achieved by application of the same control 
measures to existing sources. The EPA finds no reason to believe that 
these calculations would differ for existing sources as compared to new 
sources because the EPA believes that the baseline emissions of an 
uncontrolled source are the same, or very similar, and the efficiency 
of the control measures are the same, or very similar, compared to the 
analysis above. This is also true with respect to the costs, non-air 
environmental impacts, energy impacts, and technical limitations 
discussed above for the control options identified.
    The EPA has not identified any costs associated with applying these 
controls at existing sources, such as retrofit costs, that would apply 
any differently than, or in addition to, those costs assessed above 
regarding application of the identified controls to new sources. The 
cost effectiveness values for the option of zero emissions from 
pneumatic pumps in the natural gas processing sector range from $420 to 
$1,470 per ton of methane eliminated ($240 to $1,300 per ton 
considering savings). These cost effectiveness values are in the range 
considered reasonable by the EPA. However, as explained above in the 
context of new sources, at this time we are unclear as to whether the 
technical limitations associated with this option have been overcome 
and whether zero-emission pneumatic pumps are technically feasible. 
Therefore, at this time, we are unable to conclude that this zero-
emission option represents BSER in this proposal for the EG, but we are 
soliciting comment on this issue to better understand whether a zero-
emission option is technically feasible.
    For diaphragm pumps in the production segment the cost 
effectiveness is estimated to be $260 per ton of methane reduced using 
an existing (on site) combustion device or VRU, and $260 per ton of 
methane using an existing (on site) VRU ($80 with savings). For 
diaphragm pumps in the transmission and storage segment the cost 
effectiveness of is estimated to be $260 per ton of methane reduced 
using an existing (on site) combustion device, and $260 using an 
existing (on site) VRU. This cost effectiveness is considered 
reasonable by the EPA.
    For piston pumps in the production segment the cost effectiveness 
is estimated to be $2,400 per ton of methane reduced using an existing 
(on site) combustion device or VRU, and $2,400 per ton of methane using 
an existing (on site) VRU ($2,200 with savings). For piston pumps in 
the transmission and storage segment the cost effectiveness is 
estimated to be $2,400 per ton of methane reduced using an existing (on 
site) combustion device, and $2,400 using an existing (on site) VRU. 
This cost effectiveness is outside of the range considered reasonable 
by the EPA. In summary, the EPA did not identify any factors specific 
to existing sources, as opposed to new sources, that would alter the 
analysis above for the proposed NSPS OOOOb as applied to the designated 
pollutant (methane) and the designated facilities (pneumatic pumps). 
However, the BSER conclusion regarding piston pumps in the production 
and transmission and storage segments for the EG differs from the 
conclusion for new sources under the NSPS. As a result, the proposed 
presumptive standards for existing pneumatic pumps are as follows.
    For diaphragm pneumatic pumps in the production and transmission 
and storage segments, the presumptive standard is routing emissions to 
an existing (already on site) control device or existing (already on 
site) VRU and to a process to achieve 95 percent reduction in methane. 
For pneumatic pumps (diaphragm and piston) in the natural gas 
processing sector, the presumptive standard is a natural gas emission 
rate of zero.
    As for new sources, the EPA is specifically soliciting comment on 
whether the production and transmission storage segments should be 
subcategorized based on the availability of electricity and BSER 
determined separately for each subcategory in the EG.

H. Proposed Standards for Equipment Leaks at Natural Gas Processing 
Plants

1. NSPS OOOOb
a. Background
    In the 2012 NSPS OOOO, the EPA established VOC standards for 
equipment leaks at onshore natural gas processing plants. These 
standards were based on the Standards of Performance for Equipment 
Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry 
(NSPS VVa), which is an EPA Method 21 LDAR program generally requiring 
monthly monitoring of pumps with a leak definition of 2,000 ppm, 
quarterly monitoring of valves with a leak definition of 500 ppm, and 
annual monitoring of connectors with a leak definition of 500 ppm.\297\ 
In the 2016 NSPS OOOOa, the EPA added GHG (methane) to the title of the 
standards for equipment leaks at onshore natural gas plants but 
continued to rely on the requirements in NSPS VVa, which limited 
monitoring and repair (if found leaking) to those equipment components 
``in VOC service.'' Based on our review of the current standards, we 
are proposing to revise the equipment leak standards for onshore 
natural gas plants to more readily apply to equipment components that 
have the potential to emit methane even though they are not ``in VOC 
service.''
---------------------------------------------------------------------------

    \297\ 40 CFR part 60, subpart VVa, includes ``skip period'' 
provisions that may alter the cited monitoring frequencies.
---------------------------------------------------------------------------

b. Technology and LDAR Program Review
    The EPA acknowledges that advancements are being made in leak 
detection, including remote sensing, sensor networks, and OGI. The EPA 
already provides use of OGI as an alternative work practice at 40 CFR 
60.18(g); however, the alternative work practice requires annual EPA 
Method 21 monitoring as part of the OGI monitoring protocol. Parallel 
with this proposal, the EPA is proposing appendix K to part 60 to 
provide a standard method for OGI leak monitoring. This allows us to 
consider a wider range of LDAR programs when evaluating the BSER for 
equipment leaks at onshore natural gas processing plants. To evaluate 
different LDAR programs, we used a Monte Carlo simulation that 
simulated initiation of leaks for pumps, valves, and connectors at 
monthly intervals based on

[[Page 63232]]

component specific leak frequencies and EPA Method 21 leak size 
distributions based on historical EPA Method 21 leak data. We randomly 
assigned a mass emission rate based on the EPA Method 21 leak size 
assuming a lognormal distribution for the mass emission rate around the 
EPA Method 21 screening value correlation equation estimates. The 
simulation runs for five years for each LDAR program to build up leaks 
that might not be repaired under a given program, and compares the 
emissions estimated in the fifth year of the simulation for different 
LDAR programs. The model also records the number of repairs made in the 
fifth year of the simulation to assess the annual repair costs 
associated with the LDAR program. More information on the LDAR program 
Monte Carlo simulation and associated cost analyses is available in the 
NSPS OOOOb and EG TSD for this proposal.
    Based on our model simulation of NSPS OOOOa requirements (Method 21 
based LDAR program following the requirements in NSPS VVa), the EPA 
projects that the program achieves a 91.5 percent emission reduction 
for the components monitored. This is comparable to the projected 
control efficiencies of this LDAR program applied to similar industrial 
processes.\298\ However, when considering the components not monitored 
at the onshore natural gas processing plant because they are not ``in 
VOC service'', the overall hydrocarbon control efficiency of the 
current NSPS OOOOa requirements drops to 73.2 percent. Thus, 
significant emission reductions can be achieved by extending the 
current provisions to include all components that have the potential to 
emit methane.
---------------------------------------------------------------------------

    \298\ EPA, October 2007. ``Leak Detection and Repair--A Best 
Practices Guide.'' Office of Enforcement and Compliance Assurance. 
EPA-305-D-07-001. See ``Table 4.1--Control effectiveness for an LDAR 
program at a chemical process unit and a refinery.''
---------------------------------------------------------------------------

    Based on our model simulation of an OGI-based LDAR program, we 
found that bimonthly OGI monitoring of all equipment components (with 
potential VOC or methane emissions) using devices capable of 
identifying mass leaks at 30 g/hr and at 15 g/hr would achieve emission 
reductions of 88.5 percent and 92.2 percent, respectively. Based on the 
requirements in appendix K that the instrument be able to detect a 
methane leak of 17 g/hr, these results suggest that bimonthly OGI 
monitoring following appendix K will achieve comparable emission 
reductions as the current NSPS OOOOa requirements for the equipment 
components subject to the monitoring requirements.
c. Control Options and 2021 BSER Analysis
    The EPA then evaluated various LDAR programs for their control 
efficiency, cost and cost effectiveness for a small and a large model 
natural gas processing plant. These ``small'' and ``large'' model 
plants were based on the number of components at each facility in 
various monitoring summaries for onshore natural gas processing 
plants.\299\ We considered the (option 1) current NSPS OOOOa standards 
expanded to components that also have the potential to emit methane 
regardless of the VOC content of the stream, (option 2) bimonthly OGI 
following appendix K for all components (VOC or methane), and (options 
3 and 4) a hybrid approach following the current alternative work 
practice (regular OGI with annual EPA Method 21). For option 3 we 
evaluated requiring quarterly OGI with an annual EPA Method 21 survey 
at 10,000 ppm. For option 4 we evaluated requiring bimonthly OGI with 
an annual EPA Method 21 survey at 10,000 ppm. These control options and 
their associated costs are summarized in Tables 18 and 19 for the small 
and large model plants, respectively.
---------------------------------------------------------------------------

    \299\ See Section 10.4 of Chapter 10 ``Equipment Leaks from 
Natural Gas Processing Plants'' in the TSD located at Docket ID No. 
EPA-HQ-OAR-2021-0317.

                                                              Table 18--Summary of Control Options and Costs for Small Model Plants
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Emissions reduction (tpy)
                         Control option                          --------------------------------  Capital cost   Annual cost ($/  CE \a\ ($/ton   CE \a\ ($/ton  Incremental ($/ Incremental ($/
                                                                        VOC           Methane           ($)             yr)            VOC)          methane)        ton VOC)      ton  methane)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     Methane and VOC Service
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................................           12.34           56.95         $17,700        $114,100          $9,200          $2,000  ..............  ..............
2...............................................................           12.61           58.19           1,500          62,800           5,000           1,100        -189,100         -41,300
3...............................................................           12.64           58.33          19,200          84,500           6,700           1,400         696,200         151,100
4...............................................................           12.76           58.92          19,200          95,500           7,500           1,600          87,000          18,800
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Cost effectiveness (CE) compared to no monitoring.


                                                              Table 19--Summary of Control Options and Costs for Large Model Plants
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Emissions reduction (tpy)
                         Control option                          --------------------------------  Capital cost   Annual cost ($/  CE \a\ ($/ton   CE \a\ ($/ton  Incremental ($/ Incremental ($/
                                                                        VOC           Methane           ($)             yr)            VOC)          methane)        ton VOC)      ton  methane)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                     Methane and VOC Service
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1...............................................................           25.59          118.27         $36,200        $229,000          $9,000          $1,900  ..............  ..............
2...............................................................           26.11          120.81           3,000         123,500           4,700           1,000        -200,000         -43,100
3...............................................................           26.17          121.10          39,200         170,500           6,500           1,400         760,000         165,200
4...............................................................           26.44          122.31          39,200         191,300           7,200           1,600          79,500          17,100
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
\a\ Cost effectiveness (CE) compared to no monitoring.

    We further assumed that all facilities outsource their equipment 
leak surveys. The first year ``capital'' costs of implementing an EPA 
Method 21 program (identifying components required to be monitored and 
developing a data system to track the proper frequency to monitor each 
component) are summarized in Tables 18 and 19. Additionally, these 
tables summarize the annualized costs of conducting a complete EPA 
Method 21

[[Page 63233]]

monitoring survey of all equipment (those in VOC service or contacting 
methane), which includes the annual costs of conducting required 
surveys and making the necessary repairs as well as annualized first 
year ``capital'' costs. The first-year startup costs for OGI surveys 
are small, estimated to be $750 for small plants and $1,500 for large 
plants. Because OGI surveys can be conducted much more quickly, the 
annualized cost of conducting bimonthly OGI surveys is approximately 
half the annualized cost of EPA Method 21 surveys through NSPS VVa. 
Both EPA Method 21 and OGI LDAR programs reduce loss of product. 
Therefore, the costs of the LDAR programs are offset to some degree to 
the emissions reduced. When evaluating LDAR programs that consider all 
components (both VOC and methane), the annual value of the product not 
lost due to reduced emissions is approximately $14,000/yr.
    Based on our analysis, the resulting cost effectiveness is 
reasonable for all of the options when assigning all costs to the 
reduction of methane. When assigning all costs to VOC reduction, 
however, only the bimonthly OGI option is considered reasonable at 
$5,000/ton VOC reduced for small plants and $4,700/ton VOC reduced at 
large plants. The EPA next considered the incremental cost-
effectiveness between the four options to determine which option 
represents the BSER for equipment leaks at onshore natural gas 
processing plants. All four options achieve similar emission 
reductions, as discussed in the previous section. Bimonthly OGI (option 
2) reduces an additional 2 tpy of methane at a cost savings. Adding 
annual EPA Method 21 to bimonthly OGI monitoring (option 4) reduces an 
additional 1.5 tpy methane for large model gas plant but at significant 
cost well above any costs the EPA would consider appropriate, at 
approximately $45,000/ton methane reduced (comparing option 4 with 
option 2). Therefore, the EPA does not consider it reasonable to 
require the additional of annual EPA Method 21.
    Based on the discussion above, we consider a bimonthly OGI LDAR 
program following appendix K that includes all equipment components 
that have the potential to emit VOC or methane to be BSER for new 
sources. Therefore, we are proposing this LDAR requirement for new 
sources under NSPS OOOOb. Because an EPA Method 21 monitoring program 
based on the requirements of NSPS VVa when applied to all equipment 
components that have the potential to emit VOC or methane is projected 
to achieve similar emission reductions, we are proposing that this EPA 
Method 21-based LDAR program may be used as an alternative to bimonthly 
OGI surveys.
    In the development of the 2012 NSPS OOOO, we found that NSPS VVa 
provisions for PRDs, open-ended valves or lines, and closed vent 
systems and equipment designated with no detectable emissions were 
BSER. Available information since then continues to support this 
conclusion. Therefore, we are proposing to retain the current 
requirements in the 2016 NSPS OOOOa (which adopts by reference specific 
provisions NSPS VVa) for PRDs, open-ended valves or lines, and closed 
vent systems and equipment designated with no detectable emissions, 
except expanding the applicability to sources that have the potential 
to emit methane. The EPA is soliciting information that would support 
the use of the proposed bimonthly OGI monitoring requirement for these 
equipment components in place of the NSPS VVa annual EPA Method 21 
monitoring.
    The EPA requests comments on ways to streamline approval of 
alternative LDAR programs using remote sensing techniques, sensor 
networks, or other alternatives for equipment leaks at onshore natural 
gas processing plants. Based on our Monte Carlo equipment leak model 
that assumes well-implemented LDAR programs with no delayed repair, 
both an EPA Method 21 based program following NSPS VVa and a bimonthly 
OGI monitoring program following appendix K are projected to achieve a 
91-percent emission reduction effectiveness. We request comment on 
whether providing such an emission reduction target and equipment leak 
modeling tool to simulate LDAR under similar ``ideal'' program 
implementation conditions may facilitate future equivalency 
determinations.
2. EG OOOOc
    The application of an LDAR program at an existing source is the 
same as at a new source because there is no need to retrofit equipment 
at the site to achieve compliance with the work practice standard. The 
cost effectiveness for implementing a bimonthly OGI LDAR program for 
all equipment components that have the potential to emit methane is 
approximately $850/ton methane reduced. As explained above, the cost 
effectiveness of this OGI monitoring option is within the range of 
costs we believe to be reasonable for methane reductions. Therefore, we 
consider a bimonthly OGI LDAR program following appendix K that 
includes all equipment components that have the potential to emit 
methane to be BSER for existing sources.

I. Proposed Standards for Well Completions

1. NSPS OOOOb
a. Background
    Pursuant to CAA section 111(b)(1)(B), the EPA reviewed the current 
standards in NSPS OOOOa for well completions and proposes to determine 
that they continue to reflect the BSER for reducing methane and VOC 
emissions during oil and natural gas well completions following 
hydraulic fracturing and refracturing. Accordingly, we are not 
proposing revisions to these standards. Provided below are a 
description of the affected facilities, the current standards, and a 
summary of our review.
    Natural gas and oil wells all must be ``completed'' after initial 
drilling in preparation for production. Well completion activities not 
only will vary across formations but can vary between wells in the same 
formation. Over time, completion and recompletion activities may change 
due to the evolution of well characteristics and technology 
advancement. Well completion activities include multiple steps after 
the well bore hole has reached the target depth. Developmental wells 
are drilled within known boundaries of a proven oil or gas field and 
are located near existing well sites where well parameters are already 
recorded and necessary surface equipment is in place. When drilling 
occurs in areas of new or unknown potential, well parameters such as 
gas composition, flow rate, and temperature from the formation need to 
be ascertained before surface facilities required for production can be 
adequately sized and brought on site. In this instance, exploratory 
(also referred to as ``wildcat'') wells and field boundary delineation 
wells typically either vent or combust the flowback gas.
    One completion step for improving oil and gas production is to 
fracture the reservoir rock with very high-pressure fluid, typically a 
water emulsion with a proppant (generally sand) that ``props open'' the 
fractures after fluid pressure is reduced. Natural gas emissions are a 
result of the backflow of the fracture fluids and reservoir gas at high 
pressure and velocity necessary to clean and lift excess proppant to 
the surface. Natural gas from the completion backflow escapes to the 
atmosphere during the reclamation of water, sand, and hydrocarbon 
liquids during the collection of the multi-phase mixture directed to a 
surface impoundment. As the fracture fluids are depleted, the

[[Page 63234]]

backflow eventually contains a higher volume of natural gas from the 
formation. Due to the specific additional equipment and resources 
involved and the nature of the backflow of the fracture fluids, 
completions involving hydraulic fracturing have higher costs and vent 
substantially more natural gas than completions not involving hydraulic 
fracturing.
    During its lifetime, wells may need supplementary maintenance, 
referred to as recompletions (these are also referred to as workovers). 
Recompletions are remedial operations required to maintain production 
or minimize the decline in production. Examples of the variety of 
recompletion activities include completion of a new producing zone, re-
fracture of a previously fractured zone, removal of paraffin buildup, 
replacing rod breaks or tubing tears in the wellbore, and addressing a 
malfunctioning downhole pump. During a recompletion, portable equipment 
is conveyed back to the well site temporarily and some recompletions 
require the use of a service rig. As with well completions, 
recompletions are highly specialized activities, requiring special 
equipment, and are usually performed by well service contractors 
specializing in well maintenance. Any flowback event during a 
recompletion, such as after a hydraulic fracture, will result in 
emissions to the atmosphere unless the flowback gas is captured.
    When hydraulic re-fracturing (recompletions) is performed, the 
emissions are essentially the same as new well completions involving 
hydraulic fracture, except that surface gas collection equipment will 
already be present at the wellhead after the initial fracture. The 
flowback velocity during re-fracturing will typically be too high for 
the normal wellhead equipment (separator, dehydrator, lease meter), 
while the production separator is not typically designed for separating 
sand.
    Flowback emissions are a result of free gas being produced by the 
well during well cleanup event, when the well also happens to be 
producing liquids (mostly water) and sand. The high rate flowback, with 
intermittent slugs of water and sand along with free gas, is directed 
to an impoundment or vessels until the well is fully cleaned up, where 
the free gas vents to the atmosphere while the water and sand remain in 
the impoundment or vessels. Therefore, nearly all of the flowback 
emissions originate from the recompletion process but are vented as the 
flowback enters the impoundment or vessels. Minimal amounts of 
emissions are caused by the fluid (mostly water) held in the 
impoundment or vessels since very little gas is dissolved in the fluid 
when it enters the impoundment or vessels.
    The 2021 GHGI estimates approximately 34,000 metric tpy of methane 
emissions from hydraulically fractured completion/workover natural gas 
well events and approximately 12,000 metric tpy of methane emissions 
from hydraulically fractured completion/workover oil well events in 
2019.
b. Affected Facility
    Each affected facility is a single well that conducts a well 
completion operation following hydraulic fracturing or refracturing.
c. Current NSPS Requirements
    The current NSPS for natural gas and oil well completions and 
recompletions are the same. For well completions of hydraulically 
fractured (or refractured) wells, the EPA identified two subcategories 
of hydraulically fractured wells for which well completions are 
conducted: (1) Non-wildcat and non-delineation wells (subcategory 1 
wells); and (2) wildcat and delineation wells and low-pressure wells 
(subcategory 2 wells). A wildcat well, also referred to as an 
exploratory well, is a well drilled outside known fields or is the 
first well drilled in an oil or gas field where no other oil and gas 
production exists. A delineation well is a well drilled to determine 
the boundary of a field or producing reservoir.
    In the 2016 NSPS OOOOa rule, the EPA finalized operational 
standards for non-wildcat and non-delineation wells (subcategory 1 
wells) that required a combination of REC and combustion. Because RECs 
are not feasible for every well at all times during completion or 
recompletion activities due to variability of produced gas pressure 
and/or inert gas concentrations, the rule allows for wellhead owners 
and operators to continue to reduce emissions when RECs are not 
feasible due to well characteristics (e.g., wellhead pressure or inert 
gas concentrations) by using a completion combustion device. For 
wildcat and delineation wells and low-pressure wells (subcategory 2 
wells), the EPA finalized an operational standard that required either 
(1) routing all flowback directly to a completion combustion device 
with a continuous pilot flame (which can include a pit flare) or, at 
the option of the operator, (2) routing the flowback to a well 
completion vessel and sending the flowback to a separator as soon as a 
separator will function and then directing the separated gas to a 
completion combustion device with a continuous pilot flame. For option 
2, any gas in the flowback prior to the point when the separator will 
function was not subject to control. For both options (1) and (2), 
combustion is not required in conditions that may result in a fire 
hazard or explosion, or where high heat emissions from a completion 
combustion device may negatively impact tundra, permafrost, or 
waterways. Under the 2016 NSPS OOOOa rule, oil wells with a gas-to-oil 
ratio less than 300 scf of gas per stock tank barrel of oil produced 
are affected facilities but have no requirements other than to maintain 
records of the low GOR certification and a claim signed by the 
certifying official. As discussed in section X.B.1 of this preamble, in 
the 2020 Technical Rule, the EPA made certain amendments (e.g., related 
to the use of a separator, amended definition of flowback, amended 
recordkeeping and reporting requirements) to the VOC standards for well 
completions in the 2016 NSPS OOOOa, and is proposing to apply the same 
amendments to the methane standards for well completions in the 2016 
NSPS OOOOa.
d. 2021 BSER Analysis
    The two techniques considered under the previous BSER analyses that 
have been proven to reduce emissions from production segment well 
completions and recompletions include REC and completion combustion. 
REC is an approach that not only reduces emissions but delivers natural 
gas product to the sales meter that would typically be vented. The 
second technique, completion combustion, destroys the organic 
compounds. No other emissions control techniques were identified as 
being required under other rules (Federal, State, or local rules) that 
would exceed the level of control required under the 2016 NSPS OOOOa 
rule. Therefore, no other technology control requirements were 
evaluated in this review.
    Reduced emission completions, also referred to as ``green'' or 
``flareless'' completions, use specially designed equipment at the well 
site to capture and treat gas so it can be directed to the sales line. 
This process prevents some natural gas from venting and results in 
additional economic benefit from the sale of captured gas and, if 
present, gas condensate. However, as the EPA has previously 
acknowledged, there are some limitations that may exist for performing 
RECs based on technical barriers. These limitations continue to exist. 
Three main limitations for performing a REC include the proximity of 
pipelines to the well, the pressure of the produced gas, and the inert 
gas

[[Page 63235]]

concentration. These limitations are discussed below.
    For exploratory wells (in particular), no nearby sales line may 
exist. The lack of a nearby sales line incurs higher capital outlay 
risk for exploration and production companies and/or pipeline companies 
constructing lines in exploratory fields. The EPA is soliciting comment 
on how ``access to a sales line'' and a ``sales line'' should be 
defined.
    During the completion/recompletion process, the pressure of 
flowback fluids may not be sufficient to overcome the gathering line 
backpressure. In this case, combustion of flowback gas is one option, 
either for the duration of the flowback or until a point during 
flowback when the pressure increases to flow to the sales line. Another 
potential compressor application is to boost pressure of the flowback 
gas after it exits the separator. This technique is experimental 
because of the difficulty operating a compressor where there is a 
widely fluctuating flowback rate.
    Lastly, if the concentration of inert gas, such as nitrogen or 
CO2, in the flowback gas exceeds sales line concentration 
limits, venting to the atmosphere or to a combustion device of the 
flowback may be necessary for the duration of flowback or until the gas 
energy content increases to allow flow to the sales line. Further, 
since the energy content of the flowback gas may not be high enough to 
sustain a flame due to the presence of the inert gases, combustion of 
the flowback stream would require a continuous ignition source with its 
own separate fuel supply.
    Where a REC can be conducted, the achievable emission reductions 
vary according to reservoir characteristics and other parameters 
including length of completion, number of fractured zones, pressure, 
gas composition, and fracturing technology/technique. Based on several 
experiences presented at Natural Gas STAR technology transfer 
workshops, this analysis assumes 90 percent of flowback gas can be 
recovered during a REC.\300\ Gas that cannot be recovered during a REC 
can be directed to a completion combustion device in order to achieve 
an estimated 95 percent reduction in overall emissions.
---------------------------------------------------------------------------

    \300\ Memorandum to Bruce Moore, U.S. EPA from ICF Consulting. 
Percent of Emissions Recovered by Reduced Emission Completions. May 
2011.
---------------------------------------------------------------------------

    Completion combustion devices commonly found on drilling sites are 
generally crude and portable, often installed horizontally due to the 
liquids that accompany the flowback gas. These flares can be as simple 
as a pipe with a basic ignition mechanism and discharge over a pit near 
the wellhead. However, the flow directed to a completion combustion 
device may or may not be combustible depending on the inert gas 
composition of flowback gas, which would require a continuous ignition 
source. Sometimes referred to as pit flares, these types of combustion 
devices do not employ an actual control device and are not capable of 
being tested or monitored for efficiency. They do provide a means of 
minimizing vented gas and is preferable to venting.
    The efficiency of completion combustion devices, or exploration and 
production flares, can be expected to achieve 90 percent, on average, 
over the duration of the completion or recompletion.\301\ If the energy 
content of natural gas is low, then the combustion mechanism can be 
extinguished by the flowback gas. Therefore, it is more reliable to 
install an igniter fueled by a consistent and continuous ignition 
source. Because of the exposed flame, open pit flaring can present a 
fire hazard or other undesirable impacts in some situations (e.g., dry, 
windy conditions and proximity to residences). As a result, owners and 
operators may not be able to combust unrecoverable gas safely in every 
case.
---------------------------------------------------------------------------

    \301\ 77 FR 48889-48890, March 22, 2013 (Approval and 
Promulgation of Federal Implementation Plan for Oil and Natural Gas 
Well Production Facilities; Fort Berthold Indian Reservation 
(Mandan, Hidatsa, and Arikara Nation), North Dakota; Rule).
---------------------------------------------------------------------------

    Noise and heat are the two adverse impacts of completion combustion 
device operations. In addition, combustion and partial combustion of 
many pollutants also create secondary pollutants including 
NOX, CO, sulfur oxides (SOX), CO2, and 
smoke/particulates. The degree of combustion depends on the rate and 
extent of fuel mixing with air and the temperature maintained by the 
flame. Most hydrocarbons with carbon-to-hydrogen ratios greater than 
0.33 are likely to smoke. The high methane content of the gas stream 
routed to the completion combustion device, it suggests that there 
should not be smoke except in specific circumstances (e.g., energized 
fractures). The stream to be combusted may also contain liquids and 
solids that will also affect the potential for smoke.
    The previous BSER analyses cost effectiveness per ton of methane 
and VOC emissions reduced per completion event evaluated for REC, 
completion combustion, and REC and completion combustion were updated 
to 2019 dollars. The results of this updated analysis are provided 
below, and details are provided in the NSPS OOOOb and EG TSD for this 
rulemaking.
    The updated capital cost for performing a REC for a well completion 
or recompletion lasting 3 days is estimated to be $15,174 (2019 
dollars). Monetary savings associated with additional gas captured to 
the sales line is estimated based on a natural gas price of $3.13 per 
Mcf. It was assumed that all gas captured would be included as sales 
gas. The updated capital and cost for wells including completion 
combustion devices resulted in an estimated average completion 
combustion device cost of approximately of $4,198 per well completion 
(2019 dollars). For both REC and completion combustion devices, the 
capital costs are one-time events, and annual costs were conservatively 
assumed to be equal to the capital costs. The EPA also evaluated the 
costs that would be associated with using a combination of a REC and 
completion combustion device. The annual costs would be a combined 
estimated capital and annual cost of $19,371 (2019 dollars). As a 
result of updating capital/annual costs to reflect 2019 dollars and 
decreasing the control efficiency assumed for completion combustion 
from 95 percent to 90 percent, the cost effectiveness estimates are 
slightly higher, but substantially similar to previous cost 
effectiveness BSER analysis control option estimates for natural gas 
well and oil well completions and recompletions.
    For gas wells, under the single pollutant approach where all the 
costs are assigned to the reduction of methane emissions and zero to 
reduction of VOC, the cost effectiveness estimates were approximately 
$1,180 per ton of methane reduced for REC ($990 with natural gas 
savings), $330 for completion combustion, and $1,420 for a combination 
of REC and completion combustion ($1,250 with natural gas savings). If 
all costs were assigned to VOC reduction and zero to methane reduction, 
the cost effectiveness estimates were approximately $4,230 per ton of 
VOC removed for REC ($3,570 with natural gas savings), $1,170 for 
completion combustion, and $5,110 for a combination of REC and 
completion combustion ($4,490 with natural gas savings). Under the 
multipollutant approach where half the cost of control is assigned to 
the methane reduction and half to the VOC reduction, these estimates 
are approximately $590 per ton of methane reduced for REC ($500 with 
natural gas savings), $160 for completion combustion, and $710 for a 
combination of REC and completion combustion ($630 with natural gas 
savings). For VOC, the cost effectiveness

[[Page 63236]]

estimates were approximately $2,100 per ton of VOC removed for REC 
($1,790 with natural gas savings), $590 for completion combustion, and 
$2,600 for a combination of REC and completion combustion ($2,250 with 
natural gas savings).
    For oil wells, under the single pollutant approach where all the 
costs are assigned to the reduction of methane emissions and zero to 
reduction of VOC emissions, the cost effectiveness values were 
approximately $1,620 per ton of methane reduced for REC ($1,440 with 
natural gas savings), $450 for completion combustion, and $1,960 for a 
combination of REC and completion combustion ($1,790 with natural gas 
savings). Where all costs were assigned to reducing VOC emissions and 
zero to reducing methane emissions, the cost effectiveness estimates 
were approximately $5,840 per ton of VOC removed for REC ($5,190 with 
natural gas savings), $1,620 for completion combustion, and $7,070 for 
a combination of REC and completion combustion ($6,450 with natural gas 
savings). Under the multipollutant approach where half the cost of 
control is assigned to the methane reduction and half to the VOC 
reduction, these estimates are approximately $810 per ton of methane 
reduced for REC ($720 with natural gas savings), $230 for completion 
combustion, and approximately $980 for a combination of REC and 
completion combustion ($900 with natural gas savings). For VOC, the 
cost effectiveness estimates were approximately $2,920 per ton of VOC 
removed for REC ($2,600 with natural gas savings), $810 for completion 
combustion, and $3,530 for a combination of REC and completion 
combustion ($3,220 with natural gas savings).
    As noted above, the current NSPS OOOOa requirements consist of a 
combination of REC and completion combustion for hydraulically 
fractured natural gas and oil well completions. These techniques have 
been employed by the oil and gas industry since 2012 for natural gas 
well completions and 2016 for oil well completions. The EPA concludes 
that the cost effectiveness of REC, completion combustion, or a 
combination, for natural gas and oil wells are within the range that 
the EPA considers to be reasonable when considering both methane and 
VOC cost effectiveness. Since there are multiple scenarios where the 
cost effectiveness of the control measures is reasonable for natural 
gas and oil wells (including the cost effectiveness of VOC for REC and 
combined REC and completion combustion), we conclude that the overall 
cost effectiveness is reasonable.
    There are secondary impacts from the use of a completion combustion 
device, as the combustion of the gas creates secondary emissions of 
hydrocarbons, NOX, CO2, and CO. The EPA considers 
the magnitude of these emissions to be reasonable given the significant 
reduction in methane and VOC emissions that the control would achieve. 
Details of these impacts are provided in the NSPS OOOOb and EG TSD for 
this rulemaking. There are no other wastes created or wastewater 
generated from either REC or completion combustion.
    In light of the above, we determined that the current standards, 
which consist of a combination of REC and combustion, continue to 
represent the BSER for reducing methane and VOC emissions from well 
completions of hydraulically fractured or refractured oil and natural 
gas wells. We therefore propose to retain these standards in the 
proposed NSPS OOOOb.
    As discussed in section XII.I.1.c, in the 2020 Technical Rule, the 
EPA made certain amendments to the VOC standards for well completions 
in the 2016 NSPS OOOOa. For the same reasons provided in the 2020 
Technical Rule and discussed in section X.B.1 of this preamble for 
including these amendments for methane in NSPS OOOOa, the EPA is 
proposing to include these methane and VOC amendments for well 
completions in the NSPS OOOOb rule.
2. EG OOOOc
    A well completion operation following hydraulic fracturing or 
refracturing is a ``modification,'' as defined in CAA section 111(a), 
as each such well completion operation involves a physical change to a 
well that results in an increase in emissions; accordingly, each such 
operation would trigger the applicability of the NSPS. Therefore, there 
are no ``existing'' well completion operations of hydraulically 
fractured or refractured oil or natural gas wells. In light of the 
above, there are no proposed presumptive standards for such operations 
in this action.

J. Proposed Standards for Oil Wells With Associated Gas

1. NSPS OOOOb
a. Background
    Wells in some formations and shale basins are drilled primarily for 
oil production. Although the wells are drilled for oil, the wells may 
produce an associated, pressurized natural gas stream. The natural gas 
is either naturally occurring in a discrete gaseous phase within the 
liquid hydrocarbon or is released from the liquid hydrocarbons by 
separation. In many areas, a natural gas gathering infrastructure may 
be at capacity or unavailable. In such cases, if there is not another 
beneficial use of the gas at the site (e.g., as fuel) the collected 
natural gas is either flared or vented directly to the atmosphere.
    Emissions from associated gas venting and flaring are not regulated 
by either the 2012 NSPS OOOO or the NSPS OOOOa. The EPA did not 
evaluate BSER for associated gas production in either rulemaking. For 
this rulemaking, the EPA is proposing that methane and VOC emissions 
resulting from associated gas production be reduced by at least 95 
percent.
b. Definition of Affected Facility
    The EPA is proposing the definition of an oil well associated gas 
affected facility as an oil well that produces associated gas.
c. Description
    In 2019, according to the EIA, the number of onshore gas producing 
oil wells in the U.S.\302\ was 334,342 and the volume of vented and 
flared natural gas in 2019 was 523,066 million cubic feet.\303\ 
According to the 2021 GHGI, in 2019 venting of associated gas emitted 
42,051 metric tons of CH4 and 1,291 metric tons of 
CO2 and flaring of associated gas emitted 81,797 metric tons 
of CH4 and 25,355,892 metric tons of CO2.
---------------------------------------------------------------------------

    \302\ https://www.eia.gov/dnav/ng/ng_prod_oilwells_s1_a.htm. The 
number of onshore gas producing oil wells was derived from the 
``U.S. Natural Gas Number of Oil Wells'' subtracting ``Federal 
Offshore--Gulf of Mexico'' wells [336,732--2,390 = 334,342 wells].
    \303\ https://www.eia.gov/dnav/ng/ng_prod_sum_a_EPG0_VGV_mmcf_a.htm. The volume of vented and flared 
natural gas was derived from ``U.S. Natural Gas Vented and Flared'' 
subtracting ``Alaska--State Offshore'' and ``California--State 
Offshore'' and ``Federal Offshore--Gulf of Mexico'' and 
``Louisiana--State Offshore'' and ``Texas--State Offshore'' 
[538,479-825-0-14,461-45-82 = 523,066].
---------------------------------------------------------------------------

    For the 2019 reporting year in GHGRP subpart W, there were a total 
of 2,500 wells that reported emissions from the venting of associated 
gas emissions. The total emissions from these wells were just over 
33,900 metric tons of methane (848,000 metric tons CO2e). 
Over 90 percent of these methane emissions were reported in three 
basins--Gulf Coast, Williston, and Permian. Examining this information 
by State shows that almost half of the venting wells and over 64 
percent of the methane emissions from the venting of associated gas 
occurs in Texas. Texas and North Dakota account for almost 90

[[Page 63237]]

percent of the reported methane emissions from vented associated gas 
oil wells. The average methane emissions from the venting of associated 
gas in 2019 was 13.6 metric tpy per venting well. The average per State 
ranges from 0.03 tpy per venting well in California to over 340 tpy per 
venting well in North Dakota.
    The 2019 GHGRP subpart W data also show that there were over 38,000 
wells reporting that they flared associated gas, with over 21 million 
metric tons of CO2 emissions and over 68,000 metric tons of 
methane emissions. As with the venting emissions, the majority of the 
wells flaring associated gas (over 93 percent) were in the Gulf Coast, 
Williston, and Permian basins. Approximately 96 percent of the 
CO2 and methane emissions were reported in these three 
basins. The majority of the wells flaring associated gas (over 72 
percent) and emissions (over 87 percent) were from wells in Texas and 
North Dakota.
d. Control Options
    For new and existing sources (oil wells), options to mitigate 
emissions from associated gas in order of environmental and resource 
conservation benefit include:
     Capturing the associated gas from the separator and 
routing into a gas gathering flow line or collection system;
     Beneficially using the associated gas (e.g., onsite use, 
natural gas liquid processing, electrical power generation, gas to 
liquid);
     Reinjecting for enhanced oil recovery; and
     Flaring with legally and practicably enforceable limits.
    Typically, State oil and gas regulatory agencies (or, on certain 
public and Tribal lands, the BLM) regulate venting and flaring of 
associated gas from oil wells to ensure oil and natural gas resources 
are conserved and utilized in a manner consistent with their respective 
statutes. State oil and gas regulatory agencies typically encourage, 
and in some cases require, capture (conservation) over flaring, then 
flaring over venting. In addition, these State regulators have adopted 
a variety of approaches for regulating venting and flaring of 
associated gas from oil wells. Some require technical and economic 
feasibility analyses for continuing flaring beyond a certain time 
(e.g., one year). Some require gas capture plans to track and 
incrementally increase the percentage of gas captured (rather than 
flared) over prescribed timelines and some of these include provisions 
to curtail production in the event of not meeting gas capture goals. 
Many State oil and gas regulations recognize that there are times when 
gas capture may not be feasible, such as when there is no gas gathering 
pipeline to tie into, the gas gathering pipeline may be at capacity, or 
a compressor station or gas processing plant downstream may be off-
line, thus closing in the gas gathering pipeline. Venting is allowed by 
some State and regulatory agencies in certain circumstances such as 
emergency or upset conditions, during production evaluation, and well 
purging or productivity tests. In cases where venting is allowed, these 
rules typically require reporting of the volume of gas flared and 
vented (and sometimes a gas analysis), while some States combine 
flaring and venting information together in publicly accessible well 
data.
    Where flares are allowed, these State oil and gas regulations 
typically do not include monitoring, recordkeeping and reporting on the 
performance of the flare and would not be recognized as providing 
legally and practicably enforceable limits for CAA purposes. Some State 
environmental regulators address associated gas with a regulation 
stipulating flaring over venting that includes monitoring, 
recordkeeping and reporting provisions, while others regulate flaring 
over venting without monitoring requirements.
    The EPA is interested in information on, and the feasibility, of 
options to utilize associated gas in some useful manner in situations 
where a sales line is not available. In addition to use as fuel, such 
options could include conversion technologies where methane is 
converted into hydrogen or other added value chemicals. The EPA is 
interested in information on these, as well as other, technologies.
e. 2021 BSER Analysis
    In performing the BSER analysis for emissions from associated gas 
oil wells, we recognize there are similarities between the control 
options available for associated gas and those available for emissions 
from oil well completions. We are soliciting comment on these 
similarities. For both flowback emissions during oil well completions 
and associated gas production, if the infrastructure exists to allow 
the routing of the gas to a sales line (e.g., ``into a gas flow line or 
collection system''), owners and operators will almost always choose 
that option given the economic benefits of being able to sell the gas. 
For example, in the 2019 GHGRP subpart W data, applicable facilities 
reported over 1.2 trillion scf of associated gas was routed to sales 
lines. This represents only a subset of the total volume of associated 
gas sent to a sales line, as GHGRP subpart W does not require reporting 
of this volume in subbasins where the company is not also reporting 
venting or flaring associated gas.
    The environmental benefit of routing all associated gas to a sales 
line is significant, as there are no methane and VOC emissions. The EPA 
assumes that in situations where gas sales line infrastructure is 
available, there is minimal cost to owners and operators to route the 
associated gas to the sales line. While situations at well sites can 
differ, which would impact this cost, the EPA believes that in every 
situation the value of the natural gas captured and sold would outweigh 
these minimal costs of routing the gas to the sales line, thus 
resulting in overall savings. Given the prevalence of this practice, 
the environmental benefit, and the economic benefits to owners and 
operators, the EPA concludes that BSER is routing associated gas from 
oil wells to a sales line. The EPA seeks comment on this proposed BSER 
determination, including comment on how to define whether an oil well 
producing associated gas has access to a sales line for purposes of 
this BSER and what factors (such as proximity to an existing sales 
line) should bear on that determination.
    NSPS OOOOa also includes other compliance options that achieve a 
100 percent reduction in emissions from recovered flowback gas. These 
are ``re-inject the recovered gas into the well or another well, use 
the recovered gas as an onsite fuel source, or use the recovered gas 
for another useful purpose that a purchased fuel or raw material would 
serve.'' 40 CFR 60 60.5375a(a)(1)(ii). The EPA believes that, for 
associated gas from oil wells, the options of using the gas as an 
onsite fuel source or for another useful purpose are also viable 
alternatives to routing to a sales line. However, a significant 
difference exists between the short-term and relatively small volume of 
gas recovered during the limited duration of completion flowback versus 
the consistent flow of recovered gas from ongoing production from the 
well. Because of this difference, the EPA does not have information 
that supports re-injecting the associated gas into the well or another 
well as a viable emissions control alternative. Therefore, the EPA is 
specifically requesting comment on whether NSPS OOOOb should include 
re-injecting associated gas as an alternative to routing the gas to a 
sales line.
    The format of the well completion provisions in NSPS OOOOa 
recognize that routing the recovered gas to a gas flow line or 
collection system, re-

[[Page 63238]]

injecting the recovered gas, or using the recovered gas fuel or for 
another purpose may not be technically feasible. In these situations, 
owners and operators are required to route the flowback emissions to a 
completion combustion device.
    Similarly, the EPA recognizes that there are associated gas oil 
wells where there is no access to a gas sales line. Therefore, as an 
aspect of BSER in these situations, the EPA evaluated the flaring of 
the associated gas as an option to control emissions for situations 
where access to a sales line is not available.
    As discussed previously, the average annual methane emissions from 
the venting of associated gas reported in GHGRP subpart W for 2019 is 
13.6 metric tpy (14.9 tpy) per venting well. Using a representative gas 
composition for the production segment, the estimated VOC emissions 
would be 4.15 tpy per well. We conducted the BSER analysis using this 
emissions level as a representative well.
    The installation and proper operation of a flare can achieve 95 
percent and greater reduction in methane and VOC emissions. To be 
conservative, a 95 percent emission reduction was used for the BSER 
analysis. Therefore, the resulting emission reductions are 14.2 tpy 
methane and 3.9 tpy VOC.
    The capital cost of a flare is estimated to be $5,719. This was 
based on a 2011 Natural Gas Star Pro Fact Sheet and updated to 2019 
dollars. The resulting capital recovery, assuming a 7 percent interest 
rate and 15-year equipment life, was $628. The Natural Gas Star Pro 
report estimated the cost of the natural gas needed for the pilot was 
$1,800 per year. For this cost analysis, we assumed that this cost was 
not warranted since the associated gas could be used to fuel the pilot. 
We are soliciting comments on this cost estimate.
    The EPA stresses that 95 percent or greater emission reduction is 
achievable if the flare is properly operated and maintained. In order 
to ensure that this occurs, the EPA proposes to apply the requirements 
in Sec.  60.18 of the part 60 General Provisions to oil wells flaring 
associated gas. In order to account for the cost of the compliance with 
these requirements, we assumed that the associated cost would be 25 
percent of the total annual costs, or an additional $160. This results 
in a total estimated annual cost of $785. We are soliciting comment on 
the estimated costs associated with compliance with the Sec.  60.18 
monitoring, reporting, and recordkeeping costs for flares used to 
control emissions of vented associated gas emissions, and whether those 
requirements would ensure the flare is achieving the proposed emission 
reduction of 95 percent or greater.
    Based on these annual costs and the emission reductions cited 
above, the cost effectiveness, using the single pollutant method, is 
$55 per ton of methane reduction and $200 per ton of VOC reduction. 
Using the multipollutant approach, the cost effectiveness is $30 per 
ton of methane and $100 per ton of VOC. These cost effectiveness values 
are well within the range considered reasonable by the EPA.
    As discussed above, while flares significantly reduce the methane 
and VOC emissions, there are CO, CO2, and NOX 
emissions resulting from the combustion of the associated gas. We 
estimate that for the representative well, the annual emissions 
resulting from the flaring of the associated gas would be 50 tpy 
CO2, 0.1 tpy CO, and 0.03 tpy NOX. While these 
secondary impacts are not negligible, the EPA notes that emissions from 
flaring represents over an 80 percent reduction in CO2e 
emissions as compared to venting.
    Based on our analysis, we find that the BSER for reducing methane 
and VOC emissions from associated gas venting at well sites is routing 
of the associated gas from oil wells to a sales line. In the event that 
access to a sales line is not available, we are proposing that the gas 
can be used as an onsite fuel source, used for another useful purpose 
that a purchased fuel or raw material would serve, or routed to a flare 
or other control device that achieves at least a 95 percent reduction 
in emissions of methane and VOC.
    We are requesting comment on the affected facility definition and 
the overall format of the proposed requirements. The EPA is proposing 
that an associated gas oil well affected facility be each oil well that 
produces associated gas. The EPA is soliciting comments on how to 
define ``associated gas'' or an ``oil well that produces associated 
gas.'' The proposed NSPS OOOOb would require that all associated gas be 
routed to a sales line. In the event that access to a sales line is not 
available, the proposed NSPS OOOOb would require that the gas can be 
used as an onsite fuel source, used for another useful purpose that a 
purchased fuel or raw material would serve, or routed to a flare or 
other control device that achieves at least a 95 percent reduction in 
emissions of methane and VOC.
    Under this proposal, every oil well that produces associated gas 
would be an affected facility and therefore, subject to the rule. For 
those wells where the associated gas is routed to a sales line, the 
only requirement would be to certify that this is occurring. Wells that 
use the associated gas as a fuel or for another purpose would be 
required to document how it is used. If the associated gas is routed to 
a flare, all of the proposed monitoring, recordkeeping, and reporting 
requirements would apply.
    As an alternative, the EPA is soliciting comments on defining the 
affected facility as each oil well that produces associated gas and 
does not route the gas to a sales line. This would significantly reduce 
the number of affected facilities, although the burden for owners and 
operators that route the gas to a sales line would be similar. While 
they would not be required under NSPS OOOOb to maintain documentation 
that the gas is routed to a sales line, they would still need to 
maintain documentation to prove that the well was not an affected 
facility. Under this alternative, the proposed rule would require that 
the gas be used as an onsite fuel source, used for another useful 
purpose that a purchased fuel or raw material would serve, or routed to 
a flare or other control device that achieves at least a 95 percent 
reduction in emissions of methane and VOC. The EPA's concern with this 
alternative is that while we believe that most owners and operators 
would route the gas to a sales line if there is access, it would not 
specifically require routing the gas to a sales line. We expect that 
the cost of a flare, along with the associated monitoring, reporting, 
and recordkeeping costs, will provide additional incentive for owners 
and operators to connect to an available sales line. We are requesting 
comment on how, under this alternative approach, to incentivize owners 
and operators even more to capture or beneficially use associated gas. 
The EPA is specifically requesting comment on whether the proposed 
requirements will incentivize the sale or productive use of captured 
gas, and if not, other methods that the EPA could use to incentivize or 
require the sale or productive use instead of flaring.
2. EG OOOOc
    The EPA evaluated BSER for the control of methane from existing 
associated gas oil wells that do not route the gas to a sales line or 
to a process for another beneficial use (designated facilities) and 
translated the degree of emission limitation achievable through 
application of the BSER into a proposed presumptive standard for these 
facilities that essentially mirrors the proposed NSPS OOOOb.
    First, based on the same criteria and reasoning as explained above, 
the EPA is proposing to define the designated

[[Page 63239]]

facilities in the context of those that commenced construction on or 
before November 15, 2021. Based on information available to the EPA, we 
did not identify any factors specific to existing sources that would 
indicate that the EPA should change these definitions as applied to 
existing sources. As such, for purposes of the emission guidelines, the 
definition of a designated facility in terms of associated gas oil 
wells as existing oil wells with associated gas that do not route the 
gas to a sales line or to a process for another beneficial use.
    Next, the EPA finds that the control options evaluated for new 
sources for NSPS OOOOb are appropriate for consideration in the context 
of existing sources under the EG OOOOc. The EPA finds no reason to 
evaluate different, or additional, control measures in the context of 
existing sources because the EPA is unaware of any control measures, or 
systems of emission reduction, for the venting of associated gas that 
could be used for existing sources but not for new sources.
    Next, the methane emission reductions expected to be achieved via 
application of the control measures identified above for new sources 
are also expected to be achieved by application of the same control 
measures to existing sources. The EPA finds no reason to believe that 
these calculations would differ for existing sources as compared to new 
sources because the EPA believes that the baseline emissions of an 
uncontrolled source are the same, or very similar, and the efficiency 
of the control measures are the same, or very similar, compared to the 
analysis above. This is also true with respect to the costs, non-air 
environmental impacts, energy impacts, and technical limitations 
discussed above for the control options identified.
    The information presented above regarding the costs related to new 
sources and the NSPS are also applicable for existing sources. The EPA 
considers these cost effectiveness values to be reasonable. Since none 
of the other factors are different for existing sources when compared 
to the information from discussed above for new sources, the EPA 
concludes that BSER for existing sources and the proposed presumptive 
standard for EG OOOOc to be the requirement to route associated gas to 
a flare or other control device that achieves at least 95 percent 
control.
    Related to control option of flaring with legally and practicably 
enforceable limits at existing oil wells specifically, enhancing 
monitoring and performance requirements for flares at existing oil 
wells may be an important emissions reduction measure. For those 
operators who have already installed monitoring capability on their 
existing flares, the additional investment may be minimal to cover 
reporting of performance. For those existing oil wells where operators 
do not have flare monitoring installed, the EPA solicits comment both 
on the flare performance monitoring technology available and the cost 
of procuring, installing, operating and maintaining such technology. 
This could include, but is not limited to, digital pilot light 
monitors, combustion temperature, gas flow meters, gas chromatography 
(GC) units, and passive remote monitoring of combustion efficiencies at 
the flare tip. Similar technologies have been used for flares 
controlling landfill gas, including automated notifications of flare 
failure. Additional discussion of control devices, including flares, is 
included in section XIII.D of this preamble.

K. Proposed Standards for Sweetening Units

    Sulfur dioxide (SO2) standards for onshore sweetening 
units were first promulgated in 1985 and codified in 40 CFR part 60, 
subpart LLL (NSPS LLL). In 2012, the EPA reviewed the NSPS for the oil 
and natural gas sector, and the resulting 2012 NSPS OOOO rule 
incorporated provisions of NSPS LLL with minor revisions to adapt the 
NSPS LLL language to NSPS OOOO (77 FR 49489). The incorporated 
provisions required sweetening unit affected facilities to reduce 
SO2 emissions via sulfur recovery. The EPA also increased 
the SO2 emission reduction standard from the subpart LLL 
requirement for units with a sulfur production rate of at least 5 long 
tons per day (LT/D) from 99.8 percent to 99.9 percent. This change was 
based on the reanalysis of the original data used in the NSPS LLL BSER 
analysis.
    In 2016, the EPA finalized the NSPS OOOOa rule--which established 
standards for both methane and VOCs for certain equipment, process and 
activities across the oil and natural gas sector. The final 2016 NSPS 
OOOOa rule reaffirmed and included the SO2 emission 
reduction requirements as specified in the 2012 NSPS OOOO rule (81 FR 
35824).
    The EPA then amended the 2016 NSPS OOOOa rule in 2020 to correct an 
affected facility definition applicability error in the rule as it 
pertains to sweetening units. The 2016 NSPS OOOOa rule erroneously 
limited the applicability of the SO2 standards to sweetening 
units located at onshore natural gas processing plants. This limitation 
was not included in NSPS LLL, and no reason was identified as to ``why 
the extraction of natural gas liquids relates in any way to the 
SO2 standards such that the standards should only apply to 
sweetening units located at onshore natural gas processing plants 
engaged in extraction or fractionation activities'' (85 FR 57398). 
Therefore, the 2020 NSPS OOOOa final rule amendments corrected the 
affected facility description applicability error to correctly define 
affected facilities as any onshore sweetening unit that processes 
natural gas produced from either onshore or offshore wells at 40 CFR 
60.5365a(g).
    A sweetening unit refers to a process device that removes 
H2S and/or CO2 from the sour natural gas stream 
(40 CFR 60.5430a)--i.e., sweetening units convert H2S in 
acid gases (i.e., H2S and CO2) that are separated 
from natural gas by a sweetening process, like amine gas treatment, 
into elemental sulfur in the Claus process. These units can operate 
anywhere within the production and processing segments of the oil and 
natural gas source category, including as stand-alone processing 
facilities that do not extract or fractionate natural gas liquids from 
field gas (85 FR 57408, September 15, 2020).
    An estimated 6,900 tons of SO2 emissions were reported 
under the National Emissions Inventory (NEI) for Year 2017 \304\ for 
Source Classification Code 31000201 (Industrial Processes Oil and Gas 
Production, Natural Gas Production, Gas Sweetening: Amine Process) and 
SCC 31000208 (Industrial Processes, Oil and Gas Production, Natural Gas 
Production, Sulfur Recovery Units).
---------------------------------------------------------------------------

    \304\ 2017 National Emissions Inventory (NEI) Data [verbar] US 
EPA.
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    Pursuant to CAA section 111(b)(1)(B), the EPA reviewed the current 
standards in NSPS OOOOa (including the 2020 revisions) for sweetening 
units and proposes to determine that they continue to reflect the BSER 
for reducing SO2 emissions. The EPA has not identified any 
greater emissions control level than what is currently required under 
NSPS OOOOa for sweetening unit affected facilities. Therefore, the EPA 
is proposing to retain/include the current NSPS OOOOa requirements for 
sweetening units for the control of SO2 emissions from 
sweetening unit affected facilities in NSPS OOOOb. The proposed NSPS 
OOOOb maintains the requirement that each sweetening unit that 
processes natural gas produced from either onshore or offshore wells is 
an affected facility; as well as each sweetening unit

[[Page 63240]]

that processes natural gas followed by a sulfur recovery unit. Units 
with a sulfur production rate of at least 5 long tons per day must 
reduce SO2 emissions by 99.9 percent. Compliance with the 
standard is determined based on initial performance tests and daily 
reduction efficiency measurements. For affected facilities that have a 
design capacity less than 2 LT/D of H2S in the acid gas 
(expressed as sulfur), recordkeeping and reporting requirements are 
required; however, emissions control requirements are not required. 
Facilities that produce acid gas that is entirely re-injected into oil/
gas-bearing strata or that is otherwise not released to the atmosphere 
are also not subject to emissions control requirements.

XIII. Solicitations for Comment on Additional Emission Sources and 
Definitions

    The EPA is considering including additional sources as affected 
facilities under the proposed NSPS OOOOb and the proposed EG OOOOc. 
Specifically, the EPA is evaluating the potential for establishing 
standards applicable to abandoned and unplugged wells, pipeline pigging 
and related blowdown activities, and tank truck loading operations. 
While the EPA has assessed these sources based on currently available 
information, we have determined that we need additional information to 
evaluate BSER and propose NSPS and EG for these emissions sources. As 
described below, the EPA is soliciting information to assist in this 
effort.
    The EPA is also assessing whether proposed standards that would 
require 95 percent reduction based on a combustion control device as 
the BSER (e.g., standards for storage vessels, centrifugal compressors, 
pneumatic pumps, and associated gas that cannot be routed to a sales 
line