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Rule2026-03157

Rescission of the Greenhouse Gas Endangerment Finding and Motor Vehicle Greenhouse Gas Emission Standards Under the Clean Air Act

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Published

February 18, 2026

Effective

April 20, 2026

Issuing agencies

Environmental Protection Agency

Abstract

In this action, the U.S. Environmental Protection Agency (EPA) is rescinding the Administrator's 2009 findings of contribution and endangerment and repealing all greenhouse gas (GHG) emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines to effectuate the best reading of Clean Air Act (CAA) section 202(a)(1). The EPA determines that CAA section 202(a)(1) does not authorize the Agency to prescribe emission standards in response to global climate change concerns for multiple reasons, including the best reading of the statutory terms "air pollution," "cause," "contribute," and "reasonably be anticipated to endanger." This statutory interpretation is corroborated by application of the major questions doctrine. The EPA further determines that GHG emission standards for new motor vehicles and engines do not impact in any material way the public health and welfare concerns identified in the Administrator's prior findings in 2009. On these multiple and independent bases, the EPA concludes that it lacks statutory authority to regulate GHG emissions in response to global climate change concerns under CAA section 202(a)(1), and is not finalizing the additional bases for repeal set out in the proposed rule.

Full Text

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[Federal Register Volume 91, Number 32 (Wednesday, February 18, 2026)]
[Rules and Regulations]
[Pages 7686-7796]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-03157]

[[Page 7685]]

Vol. 91

Wednesday,

No. 32

February 18, 2026

Part III

Environmental Protection Agency

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40 CFR Parts 85, 86, 600, et al.

Rescission of the Greenhouse Gas Endangerment Finding and Motor Vehicle
Greenhouse Gas Emission Standards Under the Clean Air Act; Final Rule

Federal Register / Vol. 91 , No. 32 / Wednesday, February 18, 2026 /
Rules and Regulations

[[Page 7686]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 85, 86, 600, 1036, 1037, and 1039

[EPA-HQ-OAR-2025-0194; FRL-12715-02-OAR]
RIN 2060-AW71

Rescission of the Greenhouse Gas Endangerment Finding and Motor
Vehicle Greenhouse Gas Emission Standards Under the Clean Air Act

AGENCY: Environmental Protection Agency (EPA)

ACTION: Final rule.

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SUMMARY: In this action, the U.S. Environmental Protection Agency (EPA)
is rescinding the Administrator's 2009 findings of contribution and
endangerment and repealing all greenhouse gas (GHG) emission standards
for light-duty, medium-duty, and heavy-duty vehicles and engines to
effectuate the best reading of Clean Air Act (CAA) section 202(a)(1).
The EPA determines that CAA section 202(a)(1) does not authorize the
Agency to prescribe emission standards in response to global climate
change concerns for multiple reasons, including the best reading of the
statutory terms ``air pollution,'' ``cause,'' ``contribute,'' and
``reasonably be anticipated to endanger.'' This statutory
interpretation is corroborated by application of the major questions
doctrine. The EPA further determines that GHG emission standards for
new motor vehicles and engines do not impact in any material way the
public health and welfare concerns identified in the Administrator's
prior findings in 2009. On these multiple and independent bases, the
EPA concludes that it lacks statutory authority to regulate GHG
emissions in response to global climate change concerns under CAA
section 202(a)(1), and is not finalizing the additional bases for
repeal set out in the proposed rule.

DATES: This final action is effective on April 20, 2026. The
incorporation by reference of certain material listed in the action was
approved by the Director of the Federal Register as of March 27, 2023,
June 17, 2024, and June 21, 2024.

ADDRESSES:
Docket: The EPA has established a docket for this action under
Docket ID No. EPA-HQ-OAR-2025-0194. Publicly available docket materials
are available either electronically at <a href="http://www.regulations.gov">www.regulations.gov</a> or in hard
copy at Air and Radiation Docket and Information Center, EPA Docket
Center, EPA/DC, EPA WJC West Building, 1301 Constitution Ave. NW, Room
3334, Washington, DC. For further information on EPA Docket Center
services and the current status, please visit us online at <a href="http://www.epa.gov/dockets">www.epa.gov/dockets</a>.
Public Participation: Docket: All documents in the docket are
listed on the <a href="http://www.regulations.gov">www.regulations.gov</a> website. Although listed in the
index, 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 form through the EPA Docket Center at the location
listed in the ADDRESSES section of this document.

FOR FURTHER INFORMATION CONTACT: For information about this final
action, contact Alan Stout, Transportation Sector Impacts and Standards
Division, Office of Transportation and Air Quality, Environmental
Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105;
telephone number: (734) 214-4805; email address: <a href="/cdn-cgi/l/email-protection#83f0f7ecf6f7ade2efe2edc3e6f3e2ade4ecf5"><span class="__cf_email__" data-cfemail="e79493889293c9868b8689a7829786c9808891">[email&#160;protected]</span></a>.

SUPPLEMENTARY INFORMATION:
Preamble acronyms and abbreviations. Throughout this document the
use of ``we,'' ``us,'' or ``our'' is intended to refer to the EPA. 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:

[deg] C Degree Celsius
ABT Averaging, banking, and trading
ACC Advanced Clean Cars
ACT Advanced Clean Trucks
AEO Annual Energy Outlook
ANPRM Advanced notice of proposed rulemaking
APA Administrative Procedure Act
ASTM American Society for Testing and Materials
BEV Battery electric vehicle
BRICK Building Blocks for Relevant Ice and Climate Knowledge
CAA Clean Air Act
CAFE Corporate Average Fuel Economy
CBI Confidential Business Information
CFR Code of Federal Regulations
CH<INF>4</INF> Methane
CI Confidence interval
cm Centimeter
CO Carbon monoxide
CO<INF>2</INF> Carbon dioxide
CO<INF>2</INF>e Carbon dioxide equivalent
Cong. Rec. Congressional Record
CRA Congressional Review Act
CWG Climate Working Group
CY Calendar year
D.C. Circuit U.S. Court of Appeals for the District of Columbia
Circuit
DHS U.S. Department of Homeland Security
DRIA Draft Regulatory Impact Analysis
EIA Energy Information Administration
EISA Energy Independence and Security Act
EPA U.S. Environmental Protection Agency
EPCA Energy Policy and Conservation Act of 1975
EV Electric vehicle
EVSE Electric vehicle supply equipment
E.O. Executive Order
FaIR Model Finite amplitude Impulse Response (v2.2.3) climate
emulator model
FCEV Fuel cell electric vehicles
FEL Family emission limit
FIP Federal Implementation Plan
FR Federal Register
GHG Greenhouse gas
GMST Global mean surface temperature
GSLR Global sea level rise
GVWR Gross vehicle weight rating
H.R. Rep. House of Representative Report
HC Hydrocarbons
HD Heavy-duty
HDV Heavy-duty vehicle
HFC Hydrofluorocarbon
ICE Internal-combustion engine
ICEV Internal-combustion engine vehicles
ICR Information collection request
IPCC United Nations Intergovernmental Panel on Climate Change
IRA Inflation Reduction Act
LD Light-duty
LDV Light-duty vehicle
MAGICC Model for the Assessment of Greenhouse Gas Induced Climate
Change
MD Medium-duty
MDV Medium-duty vehicle
MMT Million metric tons
MOVES EPA's MOtor Vehicle Emission Simulator
Mt Megatonnes
MY Model year
N<INF>2</INF>O Nitrous oxide
NAAQS National Ambient Air Quality Standards
NAS National Academy of Sciences
NASEM National Academies of Sciences, Engineering, and Medicine
NCA5 Fifth National Climate Assessment
NHTSA National Highway Traffic Safety Administration
NMOG + NO<INF>X</INF> Nonmethane organic gases and oxides of
nitrogen
NO<INF>2</INF> Nitrogen dioxide
NO<INF>X</INF> Oxides of nitrogen
NTTAA National Technology Transfer and Advancement Act
O<INF>3</INF> Ozone
OBBB One Big Beautiful Bill Act
OBD Onboard diagnostics
OMB Office of Management and Budget
OMEGA Model Optimization Model for reducing Emissions of GHGs from
Automobiles
PHEV Plug-in Hybrid Electric Vehicles
PFCs Perfluorocarbons
PM Particulate Matter
PM<INF>2.5</INF> Fine particulate matter
ppmv Parts per million by volume
PRA Paperwork Reduction Act
PSD Prevention of Significant Deterioration
Pub. L. Public Law
RESS Renewable Energy Storage System
RFA Regulatory Flexibility Act

[[Page 7687]]

RFS Renewable Fuel Standard
RIA Regulatory Impact Analysis
S. Rep. Senate Report
SAB Science Advisory Board
SCC Social Cost of Carbon
SDWA Safe Drinking Water Act
SF<INF>6</INF> Sulfur hexafluoride
SIP State Implementation Plan
SO<INF>2</INF> Sulfur dioxide
SOx Sulfur oxides
SSP2-4.5 Shared socioeconomic pathway 2 with a radiative forcing of
4.5 watts per square meter by 2100
Stat. Statutes at Large
U.S. United States
U.S.C. U.S. Code
UMRA Unfunded Mandates Reform Act
USGCRP U.S. Global Change Research Program
VOCs Volatile Organic Compounds
yr Year

Table of Contents

I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document and other related
information?
C. Judicial Review and Administrative Review
II. Executive Summary
A. Introduction
B. Need for Regulatory Action
C. Summary of Comments and Updates From the Proposal in This
Final Action
1. Issues Raised Regarding the Rulemaking Process
2. Updates From the Proposal in This Final Action
III. Background
A. The EPA's Historical Approach to CAA Section 202(a)(1)
B. Petitions for Rulemaking and Massachusetts v. EPA
C. The 2009 Endangerment Finding
D. Implementation of the 2009 Endangerment Finding
E. Reconsideration of the 2009 Endangerment Finding
IV. Legal Framework for Action
A. Rescission of the Endangerment Finding
1. Issues Raised Regarding Rescission Authority
2. Issues Raised Regarding Reliance Interests
B. Repeal of New Motor Vehicle and Engine GHG Emission Standards
V. Rescission of the Endangerment Finding
A. Best Reading of CAA Section 202(a)(1)
1. Final Rationale
2. Summary of Comments and Updates Since Proposal
B. Lack of Clear Congressional Authorization
1. Final Rationale
2. Summary of Comments and Updates Since Proposal
C. Eliminating GHG Emissions From Motor Vehicles and Engines
Would Be Futile
1. Final Rationale
2. Summary of Comments and Responses and Updates to the Final
Action
VI. Additional Proposed Bases for Rescission of the Endangerment
Finding and Repeal of GHG Emission Standards the Agency Is Not
Finalizing at This Time
A. Climate Science Alternative Basis
B. There Is No Requisite Technology for Light- and Medium-Duty
Vehicles That Meaningfully Addresses the Identified Dangers of the
Six ``Well-Mixed'' GHGs
C. There Is No Requisite Technology for Heavy-Duty Vehicles That
Addresses the Identified Dangers of the Six ``Well-Mixed'' GHGs
D. More Expensive New Vehicles Prevent Americans From Purchasing
New Vehicles That Are More Efficient, Safer, and Emit Fewer GHGs
VII. Repeal of New Motor Vehicle and Engine GHG Emission Standards
A. Scope and Impacts of Repealing the GHG Emission Standards
B. Light- and Medium-Duty Vehicle GHG Program
1. Background on the Light- and Medium-Duty Vehicle GHG Program
2. Summary of Comments and Updates to the Light- and Medium-Duty
Programs
3. Changes to the Light- and Medium-Duty Vehicle GHG Regulations
C. Heavy-Duty Engine and Vehicle GHG Program
1. Background on the Heavy-Duty Engine and Vehicle GHG Program
2. Summary of Comments and Updates to the Heavy-Duty Engine and
Vehicle Programs
3. Changes to the Heavy-Duty Engine and Vehicle GHG Regulations
VIII. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review and
Executive Order 14094: Modernizing Regulatory Review
B. Executive Order 14192: Unleashing Prosperity Through
Deregulation
C. Paperwork Reduction Act (PRA)
1. 2024 LD and MD Multi-Pollutant Emission Standards Rule
2. 2024 HD GHG Emission Standards Rule
3. Nonroad Compression-Ignition Engines and On-Highway Heavy-
Duty Engines, Supporting Statement for Information Collection
Request (March 2023 Revision)
D. Regulatory Flexibility Act (RFA)
E. Unfunded Mandates Reform Act (UMRA)
F. Executive Order 13132: Federalism
G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
H. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
J. National Technology Transfer and Advancement Act (NTTAA) and
1 CFR Part 51
K. Congressional Review Act (CRA)

I. General Information

A. Does this action apply to me?

This action relates to companies that manufacture, sell, or import
into the United States light-, medium-, or heavy-duty motor vehicles
and engines. Potentially affected categories and entities include the
following:
[GRAPHIC] [TIFF OMITTED] TR18FE26.002

This table is not intended to be exhaustive but rather provides a
guide for readers regarding entities potentially affected by this
action. This table lists the types of entities that the EPA is
presently aware could potentially be affected by this action. Other
types of entities not listed in the table could also be affected. To
determine whether your entity is regulated by this action, you should
carefully examine the applicability criteria found in Code of

[[Page 7688]]

Federal Regulations (CFR) Title 40, parts 85, 86, 600, 1036, and 1037.
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.

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

In addition to being available in the docket, an electronic copy of
this final action is available on the internet at <a href="https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-rescission-greenhouse-gas-endangerment">https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-rescission-greenhouse-gas-endangerment</a>. Following publication in the Federal
Register, the EPA will post the Federal Register version of the final
action and key technical documents at this same website.

C. Judicial Review and Administrative Review

Under CAA section 307(b)(1), judicial review of this final action
is available only by filing a petition for review in the United States
Court of Appeals for the District of Columbia Circuit (D.C. Circuit) by
April 20, 2026. Under CAA section 307(b)(2), the requirements
established by this final action may not be challenged separately in
any civil or criminal proceedings brought by the EPA to enforce the
requirements.
CAA section 307(d)(7)(B) further provides that ``[o]nly an
objection to a rule or procedure which was raised with reasonable
specificity during the period for public comment (including any public
hearing) may be raised during judicial review.'' This section also
provides a mechanism for the EPA to convene a proceeding for
reconsideration ``[i]f the person raising an objection can demonstrate
to the EPA that it was impracticable to raise such objection within
[the period for public comment] or if the grounds for such objection
arose after the period for public comment, (but within the time
specified for judicial review) and if such objection is of central
relevance to the outcome of the rule.'' Any person seeking to make such
a demonstration to us should submit a Petition for Reconsideration to
the Office of the Administrator, U.S. Environmental Protection Agency,
Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW, Washington,
DC 20460, with a copy to both the person(s) listed in the preceding FOR
FURTHER INFORMATION CONTACT section, and the Associate General Counsel
for the Air and Radiation Law Office, Office of General Counsel (Mail
Code 2344A), U.S. Environmental Protection Agency, 1200 Pennsylvania
Ave. NW, Washington, DC 20460.

II. Executive Summary

A. Introduction

In this final action, the EPA rescinds the Administrator's 2009
standalone decision entitled ``Endangerment and Cause or Contribute
Findings for Greenhouse Gases Under Section 202(a) of the Clean Air
Act,'' 74 FR 66496 (Dec. 15, 2009) (``Endangerment Finding'') and
repeals all GHG emission standards for light-duty (LD), medium-duty
(MD), and heavy-duty (HD) vehicles and engines manufactured or imported
into the United States (U.S.) for model years (MY) 2012 to 2027 and
beyond. Upon review of the underlying actions, recent decisions by the
U.S. Supreme Court, and the robust public response to the proposal, the
EPA concludes that we lack statutory authority to maintain this novel
and transformative regulatory program. The appropriate policy response
to global climate change concerns is a decision vested in Congress, and
Congress did not decide the Nation's policy response to these concerns
when it enacted CAA section 202(a)(1) to address domestic air pollution
problems nearly sixty years ago, or in any subsequent amendment
thereto. Relatedly, the EPA concludes that regulating GHG emissions
from new motor vehicles and engines under CAA section 202(a)(1) has no
material impact on global climate change concerns animating the
Agency's regulatory efforts since 2009, much less the adverse public
health or welfare impacts attributed to such global climate trends.
Climate impact modeling submitted during the public comment period, and
confirmed by our own analysis, demonstrates that even the complete
elimination of all GHG emissions from all new and existing vehicles in
the U.S. would have only de minimis impacts that fall well within the
standard margin of error for global temperature and sea level
measurement. This evidence further supports our conclusion that the
regulation of GHG emissions falls outside the scope of air pollution
problems Congress addressed when enacting CAA section 202(a)(1) and,
separately, leads us to conclude that maintaining GHG emission
standards under CAA section 202(a)(1) would be unreasonable given their
futility and the immense burdens they place on regulated parties,
consumers, and the economy.
The EPA recognizes the gravity of this decision to the many
stakeholders who submitted comments for and against to the proposal,
including with respect to global climate change concerns and the
burdens of our GHG regulatory program on manufacturers, auto workers,
and American consumer choice and affordability. We closely reviewed the
diverse array of scientific and technical information submitted in
response to the proposal. The Administrator continues to harbor
concerns regarding the scientific analysis contained in the
Endangerment Finding, including because the decision severed the
statutory analysis in multiple respects to assert the power to regulate
GHG emissions in response to global climate change concerns. However,
the Administrator is not basing this action on a new finding under CAA
section 202(a)(1). Rather, we conclude that the EPA lacks statutory
authority to resolve these questions under CAA section 202(a)(1). As
recently as 2008, the Agency correctly understood that the statute was
enacted to control air pollution that threatens health and welfare
through local and regional exposure, and that launching a GHG emissions
program under this authority would result in an unprecedented expansion
of regulatory power with profound adverse effects on the economy and
American households. With this final action, we return to fundamental
principles governing decision-making within our democratic system:
``Agencies have only those powers given to them by Congress,'' West
Virginia v. EPA, 597 U.S. 697, 723 (2022), and ``the scope of an
agency's own power'' is determined not by deference to asserted
expertise, but by ``the best reading of the statute,'' which is fixed
at the time of enactment. Loper Bright Enters. v. Raimondo, 603 U.S.
369, 400-01 (2024).
In 2009, the EPA took the unprecedented step of asserting authority
to regulate GHG emissions in a standalone action that broke new ground
and launched the Agency into a course of regulation that fundamentally
reshaped many aspects of the Nation's economic and social life.\1\ In
the Endangerment Finding, we interpreted CAA section 202(a)(1) for the
first time to authorize regulation of domestic emissions from new motor
vehicles and engines based on global climate change concerns rather
than air pollution that endangers public health or welfare

[[Page 7689]]

through local or regional exposure. 74 FR 66526-27. We relied on that
interpretation to define both the relevant ``air pollution'' and the
relevant ``air pollutant'' as the combination of six ``well-mixed
GHGs''--carbon dioxide (CO<INF>2</INF>), methane, nitrous oxide
(N<INF>2</INF>O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs),
and sulfur hexafluoride (SF<INF>6</INF>)--while reserving the right to
include additional ``climate forcers'' in these definitions in the
future. 74 FR 66516-17, 66536-37. We also asserted that because the
statute is ``silent on [the] issue,'' CAA section 202(a)(1) grants
``procedural discretion'' to issue standalone findings that trigger a
duty to regulate without considering the standards that must be issued
in response. 74 FR 66501-02. The Administrator exercised this newfound
discretion to make separate findings, without analyzing or promulgating
any emission standards, that elevated global concentrations in the
upper atmosphere of the six ``well-mixed GHGs'' constitute ``air
pollution'' that may reasonably be anticipated to endanger public
health and welfare, 74 FR 66516-36, and that GHG emissions from all
potential classes of motor vehicles and engines contribute to such
elevated global concentrations of GHGs in the upper atmosphere and
therefore to air pollution that endangers public health and welfare, 74
FR 66536-45.
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\1\ See also ``Endangerment and Cause or Contribute Findings for
Greenhouse Gases Under Section 202(a) of the Clean Air Act: EPA's
Response to Public Comments'' (``EF RTC''), available in a
Memorandum to Docket entitled ``EPA's Response to Public Comments on
the 2009 Endangerment and Cause or Contribute Findings for
Greenhouse Gases: Volumes 1-11,'' Document ID EPA-HQ-OAR-2025-0149.
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With respect to endangerment, the Administrator found that global
concentrations of six ``well-mixed'' GHGs from all foreign and domestic
sources ``constitute the largest anthropogenic driver of climate
change'' and attributed climate change impacts to global GHG
concentrations. 74 FR 66517. Next, the Administrator summarized
literature reviews finding that climate change ``can increase the risk
of morbidity and mortality'' indirectly through increased global
temperature, air quality effects, and effects on extreme weather events
and can impact welfare indirectly through impacts on sea level rise and
coastal areas, food production and agriculture, forestry, water
resources, energy, infrastructure, and settlements, and ecosystems and
wildlife. 74 FR 66523-35. On that basis, the Administrator found that
global concentrations of six ``well-mixed'' GHGs constitute ``air
pollution'' that endangers public health and welfare. 74 FR 66516. For
purposes of this preamble, we use the phrase ``global climate change
concerns'' to refer to the public health and welfare risks the
Administrator associated with global climate change in the Endangerment
Finding and subsequent actions since 2009.
With respect to causation or contribution, the Administrator used
annual emissions data for existing motor vehicles and engines from 2005
to project that all potential classes of new motor vehicles and engines
would emit four GHGs--CO<INF>2</INF>, methane, N<INF>2</INF>O, and
HFCs--that collectively amounted to 4.3 percent of annual global GHG
emissions and implicitly would continue in future years. 74 FR 66543.
The Administrator acknowledged that a greater degree of contribution
would usually be required to meet the statute's contribution element
``when addressing a more typical local or regional air pollution
problem.'' 74 FR 66539. Nevertheless, asserting discretion to interpret
the ambiguous term ``contribute,'' the Administrator found that the
``unique'' nature of global climate change meant that ``contributors
must do their part even if their contributions to the global climate
change problem, measured in terms of percentage, are smaller than
typically encountered when tackling solely regional or local
environmental issues.'' 74 FR 66542-43. In other words, the
Administrator justified the Endangerment Finding on the theory that
although the situation was ``unique'' and the ``contribution'' of
domestic new motor vehicles and engines was not in line with the
Agency's prior course of regulation under CAA section 202(a)(1), action
was needed because all source categories and all other nations must
``do their part'' to avoid ``a tragedy of the commons.'' Id. On that
basis, the Administrator found that annual emissions from new motor
vehicles and engines ``contributed'' to the ``air pollution,'' defined
anew for those purposes as the accumulated global concentrations of the
six ``well-mixed'' GHGs, that endangered public health and welfare by
giving rise to global climate change concerns. 74 FR 66537.
The EPA subsequently relied on the Endangerment Finding to impose
increasingly stringent GHG emission standards for new motor vehicles
and engines and to attempt, largely without success, to extend the GHG
initiative into additional CAA programs. In Utility Air Regulatory
Group v. EPA, 573 U.S. 302 (2014) (UARG), the Supreme Court largely
rejected our attempt to extend GHG emission standards to stationary
sources subject to Title I and Title V requirements as exceeding our
authority under the CAA, including because we admitted that applying
the statutory scheme as written to GHG emissions from most covered
stationary sources would be unworkable and attempted to rewrite the
statute by regulation. And in West Virginia v. EPA, 597 U.S. 697
(2022), the Court vacated our attempt to shift the power grid away from
using fossil fuels through GHG standards for existing power plants
under CAA section 111(d). The Court held in both cases that the agency
actions at issue implicated the major questions doctrine and that
Congress must clearly authorize agencies to take actions that decide
major questions of policy. Nevertheless, the EPA continued to retain
and expand GHG emission standards for new motor vehicles and engines
that impose billions of dollars in annual compliance costs on American
businesses and consumers and reflect an increasing trend toward forcing
a transition to the use of electric vehicles (EVs) rather than
gasoline- or diesel-fueled motor vehicles and engines.\2\ Meanwhile,
global GHG concentrations in the upper atmosphere have continued to
rise, driven primarily by increased emissions from foreign sources,\3\
all without producing the degree of adverse impacts to public health
and welfare in the U.S. anticipated in the 2009 Endangerment
Finding.\4\
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\2\ The EPA is not relying on the Regulatory Impact Analysis
(RIA) prepared pursuant to Executive Order (E.O.) 12866 in any of
the bases for this final action. Except where expressly stated, none
of the legal bases for repeal in section V of this preamble reflect
cost considerations, which are not relevant for purposes of this
final action in determining the best reading of CAA section
202(a)(1). For the limited instances in which cost is relevant as a
general consideration, we discuss cost separately from, and do not
rely upon, the RIA prepared pursuant to E.O. 12866.
\3\ Crippa, M. et al. (2023). GHG emissions of all world
countries. Publications Office of the European Union: <a href="https://doi.org/10.2760/953322">https://doi.org/10.2760/953322</a>.
\4\ The EPA is not relying on new findings by the Administrator
with respect to global climate change concerns under CAA section
202(a)(1) as a basis for the rescission or repeals and is not
finalizing the alternative basis set out in section IV.B of the
preamble to the proposed rule. We are rescinding the Endangerment
Finding and repealing all associated GHG emission standards for the
reasons discussed in this preamble, which make it unnecessary and
inappropriate to resolve outstanding scientific questions regarding
global climate change concerns in the regulatory context of CAA
section 202(a)(1). Nevertheless, the bases for this final action
should not be understood as an additional endorsement or
ratification of the scientific analysis in the Endangerment Finding.
See section VI.A of this preamble for further discussion.
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Upon reconsideration, the EPA now acknowledges that the
Endangerment Finding and subsequent regulations exceeded the Agency's
statutory authority under CAA section 202(a)(1). These actions rested
on a profound misreading of the Supreme Court's decision in
Massachusetts v. EPA, 549 U.S. 497 (2007), which vacated the denial of
a petition for rulemaking in

[[Page 7690]]

which we concluded that CO<INF>2</INF> and three other GHGs fell
outside the statutory definition of ``air pollutant'' in CAA section
302(g) and should not be regulated for additional policy reasons. As we
later explained in a 2008 advance notice of proposed rulemaking
entitled ``Regulating Greenhouse Gas Emissions Under the Clean Air
Act,'' the statute was ``enacted to control regional pollutants that
cause direct health effects,'' and regulating GHG emissions under its
provisions ``could result in an unprecedented expansion of EPA
authority that would have a profound effect on virtually every sector
of the economy and touch every household in the land.'' 73 FR 44354,
44355 (July 30, 2008) (``2008 ANPRM''). Intervening legal developments
reinforce our conclusion that Congress did not decide the Nation's
policy response to global climate change concerns in CAA section
202(a)(1), let alone clearly authorize the EPA to make that policy
choice by prescribing emission standards that force a transition to
EVs. Nor does climate impact modeling suggest that the EPA's initiative
has been anything but futile, which further supports the conclusion
that CAA section 202(a)(1) was not designed with such a problem in
mind. The inability of the EPA's GHG emission standards to materially
impact the identified risks both corroborates the interpretation of CAA
section 202(a)(1) adopted in this final action and serves as an
independent basis to revoke those standards, separate and apart from
the question of statutory interpretation and of the nature of the EPA's
authority under this provision.
The remainder of this section describes the need for regulatory
action and the scope of this final action, the repeal of new motor
vehicle and engine GHG emission standards for MYs 2012 to 2032 and
beyond, and minor conforming adjustments to unrelated emission
standards for new motor vehicles and engines that we are not altering
as part of this rulemaking. We acknowledge that the EPA's decision to
regulate new motor vehicle and engine GHG emissions has caused
significant expenditure of resources by, and an imposition of burdens
on, Federal, State, local, and private-sector entities, and consider
those interests to the extent possible consistent with limits on our
statutory authority. These interests emphasize the need for urgent
action to avoid further expenditures in reliance on an unlawful
regulatory framework that does not further public health or welfare in
any material respect relevant to the global climate change concerns
identified and relied upon in the 2009 Endangerment Finding.
Section III of this preamble sets out relevant background,
including the EPA's prior positions on regulating GHGs, the Supreme
Court's decision in Massachusetts, the EPA's response in the 2008 ANPRM
and events leading up to the Endangerment Finding, the approach taken
in the Endangerment Finding, and the regulations issued by the EPA
since 2009 as a result of the Endangerment Finding. We also summarize
the premises, assumptions, and conclusions in the Endangerment Finding
and the developments since 2009 that led the Administrator to develop
concerns sufficient to initiate reconsideration of the ongoing validity
and reliability of the Endangerment Finding in early 2025.
Section IV of this preamble describes our legal authority to
rescind the Endangerment Finding and repeal the resulting GHG emission
standards issued under CAA section 202(a)(1). Because this final action
does not impact fuel economy standards or emission standards for
criteria pollutants and hazardous air pollutants regulated under the
CAA, we explain the relationship between these regulations to set the
outer bounds of the amendments at issue in this rulemaking. We
summarize comments received on our authority for this final action,
which largely acknowledged that the EPA may reconsider the prior
actions covered by this rulemaking provided that we offer an adequate
basis for the rescission and repeals, along with our responses to these
comments.
Section V.A of this preamble finalizes the rescission and repeals
of these prior actions on the basis that the Endangerment Finding
exceeded our statutory authority under CAA section 202(a)(1). First, we
conclude that the term ``air pollution'' as used in CAA section
202(a)(1) is best read in context as pollution that threatens health or
welfare through local or regional exposure, consistent with the
ordinary meaning of the term at the time of enactment, the statute's
structure and history, and the EPA's longstanding practice before 2009.
Second, we conclude that CAA section 202(a)(1) does not grant the
Administrator ``procedural discretion'' to issue standalone findings
that trigger a duty to regulate without analyzing and promulgating the
required emission standards, or, conversely, to prescribe standards
without making the requisite findings for the air pollutant emissions
and class or classes of new motor vehicles or engines at issue. Third,
we conclude that CAA section 202(a)(1) does not authorize the
Administrator to sever the finding of endangerment from the finding of
causation or contribution such that there is no nexus between the
emissions at issue and the identified dangers to public health or
welfare. Rather, CAA section 202(a)(1) requires the Administrator to
find that the relevant air pollutant emissions from the class or
classes of new motor vehicles or engines at issue cause, or contribute
to, the same air pollution that the Administrator finds endangers
public health or welfare, without relying on international emissions
not covered by the statute. As the Supreme Court made clear in Loper
Bright, we can no longer rely on statutory silence or ambiguity to
expand our regulatory power. We also explain that the EPA reached
contrary conclusions in the Endangerment Finding by redefining key
statutory terms and misconstruing the Supreme Court's decision in
Massachusetts, which, even on its own terms, did not purport to require
the Agency to launch a GHG regulatory program under CAA section
202(a)(1). We briefly summarize the public comments received for and
against this interpretation, including with respect to the meaning of
``air pollution'' in context and the scope of Massachusetts, as well as
our general responses to these comments.
Section V.B of this preamble finalizes the rescission and repeals
on the additional basis that the Nation's potential response to global
climate change concerns is an issue that has significant economic and
policy impacts, including to Americans' basic way of life, that
Congress did not clearly authorize the EPA to decide by invoking
authority to prescribe emission standards under CAA section 202(a)(1).
We conclude, consistent with West Virginia, UARG, and other relevant
precedents, that the Nation's policy response to global climate change
concerns is a question for Congress to decide in the first instance.
Because nothing in the statute clearly authorizes the Administrator to
assert the power to resolve this major question by prescribing emission
standards, let alone by mandating a shift toward EVs, we conclude that
CAA section 202(a)(1) does not authorize the Endangerment Finding or
subsequent regulations. We briefly summarize public comments received
for and against this invocation of the major questions doctrine,
including the assertion by some commenters that Massachusetts shields
CAA section 202(a)(1) from this analysis, and our general responses to
these comments.

[[Page 7691]]

Section V.C of this preamble sets out the robust public response to
our request for comments on the efficacy of new motor vehicle and
engine GHG emission standards in addressing the global climate change
concerns animating the Endangerment Finding and subsequent regulations.
We summarize the climate impact modeling submitted by commenters and
the updated modeling we performed to evaluate the competing data and
conclusions received. As explained below, we conclude that even the
complete elimination of all GHG emissions from all new and existing LD,
MD, and HD vehicles in the U.S. would not alter predicted trends in
global mean surface temperature (GMST) \5\ or global mean sea level
rise (GSLR) \6\ beyond de minimis levels that are below the accepted
variability in GMST and GSLR measurement. Assuming for purposes of this
final action the validity and the uncertainties inherent in the
relevant models, the EPA estimates that the elimination of all U.S.
vehicle and engine GHG emissions would result in an approximately 0.013
degree Celsius ([deg]C) difference in GMST increase by 2050 compared to
the baseline and an approximately 0.037 [deg]C difference by 2100
compared to the baseline. Using similar methods, we estimate that this
scenario would result in an approximately 0.09-centimeter (cm)
difference in GSLR by 2050 compared to the baseline and an
approximately 1.40 cm difference by 2100 compared to the baseline. For
context, variability in GMST measurement from 2016 to 2025 was 0.14
[deg]C, which is almost four times greater than the modeled GMST impact
by 2100 of eliminating all U.S. vehicle and engine GHG emissions.\7\
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\5\ As GMST is a widely used metric for tracking temperature
changes related to global climate change concerns, we use the term
interchangeably with ``global temperature'' within this preamble and
supporting documentation.
\6\ As GSLR is a widely used metric for tracking sea level rise
related to global climate change concerns, we use the term
interchangeably with ``global sea level,'' ``sea level,'' and ``sea
level rise'' within this preamble and supporting documentation.
\7\ NOAA National Centers for Environmental Information, Climate
at a Glance: Global Time Series, NOAAGlobalTemp, (Jan. 2026)
available at <a href="https://ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/land_ocean/tavg/ytd/12/1950-2025">https://ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/land_ocean/tavg/ytd/12/1950-2025</a>.
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Importantly, this scenario is a dramatic overestimation of the
potential impacts of GHG emission standards, which apply only to new
vehicles and engines and do not eliminate emissions from existing
vehicles. Taking this reality into account, the anticipated impact of
GHG emission standards under CAA section 202(a)(1) is a further
fraction of the modeled impacts of eliminating all U.S. vehicle and
engine GHG emissions. Under an illustrative scenario in which the
modeled impacts are discounted by 50 percent, which generally reflects
the emission reductions requirements of the EPA's most recent 2024 LD
and MD Multi-Pollutant Emission Standards Rule and 2024 HD GHG Emission
Standards Rule (together, 2024 GHG Emission Standards Rules) that
further restricted GHG emissions from MY 2027 levels for MY 2032 and
beyond, we estimate an approximately 0.007 [deg]C difference in GMST
increase by 2050 and 0.019 [deg]C by 2100 and an approximately 0.005 cm
difference in GSLR by 2050 and 0.7 cm by 2100, all of which amount to
one percent or less of the total projected change from the baseline. We
conclude that these impacts are de minimis and that the futility of GHG
emission standards under CAA section 202(a)(1) further supports the
understanding that Congress did not design that provision to authorize
or require the Administrator to prescribe standards in response to
global climate change concerns. In addition, we conclude that the
futility of the GHG emission standards renders maintaining such
regulations unreasonable, separate and apart from the validity of the
Endangerment Finding, because the enormous costs imposed do not
materially further public health or welfare. Under any legal standard,
it is unreasonable for the EPA to impose trillions of dollars in costs
on manufacturers and American consumers in exchange for results that do
not materially further congressional objectives--at least absent an
extraordinarily clear indication in the statutory text. We briefly
summarize public comments received on these aspects of the proposal and
set out our general responses, including the assertion by some
commenters that Massachusetts requires EPA to ignore the practical
effect of its regulations when making findings under CAA section
202(a)(1) and when promulgating the regulations required by such
findings.
Section VI of this preamble describes the additional bases in the
proposal that we are not finalizing in this action, including the
alternative basis in section IV.B of the preamble to the proposed rule
that the Administrator exercise discretion under CAA section 202(a)(1)
to rescind the Endangerment Finding and repeal associated regulations
by making a superseding finding. We received comments in support of
this alternative basis, including from commenters asserting that the
EPA compiled and analyzed the scientific record unreasonably in 2009 by
severing the analysis of endangerment and contribution and issuing
findings separately from emission standards and from commenters
asserting that the scientific record did not then, or does not now,
provide the certainty necessary to make such findings. We also received
comments in opposition to this alternative basis, including from
commenters asserting that the scientific record supporting the findings
is ``overwhelming'' and has been strengthened in the intervening years.
Although the Administrator continues to harbor concerns regarding many
of the scientific inputs and analyses underlying the Endangerment
Finding, we are not finalizing this alternative given our conclusion
that the EPA lacks statutory authority to regulate in response to
global climate change concerns under CAA section 202(a)(1). The legal
interpretation finalized in this action means that we cannot resolve
remaining scientific controversies in this regulatory context and
renders it unnecessary and inappropriate to invoke the Administrator's
authority to exercise judgment on these questions under that
provision.\8\ Furthermore, we explain that we are not finalizing
several of the additional bases for repealing GHG emission standards
set out in section V of the preamble to the proposed rule, which are
similarly unnecessary given the predicate conclusion on the scope of
our authority under CAA section 202(a)(1). We briefly summarize the
input received on these alternatives in the interests of transparency
and public engagement but are not responding to comments on these
specific issues, which are outside the scope of the bases for this
final action.
---------------------------------------------------------------------------

\8\ For similar reasons, and in light of concerns raised by some
commenters about the draft report authored by the U.S. Department of
Energy's Climate Working Group (CWG), the EPA is not relying on the
May 27, 2025 CWG draft report entitled ``Impact of Carbon Dioxide
Emissions on the U.S. Climate'' or the July 23, 2025 CWG report
entitled ``A Critical Review of Impacts of Greenhouse Gas Emissions
on the U.S. Climate'' for any aspect of this final action.
---------------------------------------------------------------------------

Section VIII of this preamble details the scope of the repeals,
including its relationship to distinct regulatory programs and Federal
preemption, the revisions to 40 CFR parts 85, 86, 600, 1036, 1037, and
1039 required to effectuate repeal of all new motor vehicle and engine
GHG emission standards, and conforming adjustments to regulatory
provisions that we did not reopen or propose to substantively revise.
Specifically, we are not changing

[[Page 7692]]

elements of the regulations that are necessary for programs unrelated
to the GHG emission standards, including emission standards for
criteria pollutants, emission standards for hazardous air pollutants,
or regulatory provisions related to the EPA's statutory role in vehicle
fuel-economy standards administered by the National Highway Traffic
Safety Administration (NHTSA).
As explained in detail below, the conclusions presented in sections
V.A, V.B, and V.C of this preamble provide independent grounds for
rescinding the 2009 Endangerment Finding and repealing the GHG emission
standards. Moreover, the conclusions in section V.A of this preamble--
that ``air pollution'' as used in CAA section 202(a)(1) is best read as
pollution that threatens public health or welfare through local or
regional exposure; that the Administrator cannot trigger the duty to
regulate without analyzing and promulgating standards; and that the
finding of endangerment cannot be severed from the finding of causation
of contribution--are all also independent conclusions that stand on
their own. Each basis for this final action presented in section V of
this preamble is severable, and each basis alone provides sufficient
justification to rescind the Endangerment Finding and repeal the GHG
emission standards for new motor vehicles and engines. If any basis is
determined in the course of judicial review to be invalid, that partial
invalidation will not affect the other bases, and the EPA intends the
remainder of this final action stand on the remaining basis or bases.
This preamble includes an overview of the EPA's rationale,
including several technical documents developed in support of this
final action, as well as summaries of comments received during the
public hearing on the proposal, additional consultation and listening
sessions, and via the rulemaking docket. For a full summary of comments
received and our complete responses thereto, please see the ``Response
to Comments'' document available in the docket for this rulemaking.\9\
The final Regulatory Impact Analysis (RIA) for this rulemaking, on
which we did not rely for any aspect of this final action, is also
available in the docket for this rulemaking.\10\
---------------------------------------------------------------------------

\9\ ``Rescission of the Greenhouse Gas Endangerment Finding and
Motor Vehicle Greenhouse Gas Emission Standards Under the Clean Air
Act: Response to Comments.'' EPA 420-R-26-003. February 2026.
\10\ ``Rescission of the Greenhouse Gas Endangerment Finding and
Motor Vehicle Greenhouse Gas Emission Standards Under the Clean Air
Act: Regulatory Impact Analysis.'' EPA-420-R-26-002. February 2026.
---------------------------------------------------------------------------

B. Need for Regulatory Action

Immediately upon taking office in 2025, President Trump established
as the policy of the United States new Executive Branch priorities for
energy, transportation, and consumer choice and committed agencies to
ensuring regulations remain within constitutional and statutory bounds.
On January 20, 2025, the President issued E.O. 14154, entitled
``Unleashing American Energy,'' to address the burdens placed by
unnecessary regulations on energy affordability, job creation, and
national security.\11\ The President directed the Administrator to
submit recommendations to the Director of the Office of Management and
Budget (OMB) on the legality and continuing applicability of the 2009
Endangerment Finding.\12\ On February 19, 2025, the President issued
E.O. 14219, entitled ``Ensuring Lawful Governance and Implementing the
President's `Department of Government Efficiency' Deregulatory
Initiative,'' which further instructed agencies, including the EPA, to
review existing regulations for consistency with the Constitution and
the best reading of the authorizing statute.\13\
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\11\ Executive Order 14154, 90 FR 8353 (Jan. 29, 2025).
\12\ Id. section 6(f).
\13\ Executive Order 14219, 90 FR 10583 (Feb. 25, 2025).
---------------------------------------------------------------------------

Upon confirmation by the Senate, Administrator Lee Zeldin committed
the EPA to prioritizing its core statutory missions and ensuring that
all regulatory actions are clearly grounded in statutory authority and
the best reading of the law. As part of these efforts, and consistent
with E.O. 14154, the Administrator initiated a review of the legality
and applicability of the Endangerment Finding. On February 19, 2025,
the Administrator submitted a memorandum to the OMB Director
recommending that the EPA reconsider the Endangerment Finding to
address legal and scientific developments that appeared to undermine
the bases for that action and subsequent regulations.\14\ The
Administrator noted that recent Supreme Court decisions, including
Loper Bright, West Virginia, UARG, and Michigan v. EPA, 576 U.S. 743
(2015), provided further instruction as to how we should interpret and
apply the statutes Congress entrusted us to administer.\15\ The
Administrator further noted that the Endangerment Finding recognized
significant uncertainties in its conclusions and assumptions that
should be evaluated in light of more recent empirical data and
scientific evidence.\16\ Accordingly, the Administrator announced on
March 12, 2025, that the EPA would reconsider the Endangerment Finding
and subsequent actions to determine whether our GHG regulations have an
adequate statutory basis and to seek public input on developments since
2009.\17\
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\14\ Memorandum from Lee Zeldin, Administrator, U.S.
Environmental Protection Agency, to Russell Vought, Director, Office
of Management and Budget (Feb. 19, 2025) (Feb. 19, 2025 Memo),
available in the docket for this rulemaking.
\15\ Id. at 1.
\16\ Id. at 8.
\17\ ``Trump EPA Kicks Off Formal Reconsideration of
Endangerment Finding with Agency Partners'' (Mar. 12, 2025),
available at <a href="https://www.epa.gov/newsreleases/trump-epa-kicks-formal-reconsideration-endangerment-finding-agency-partners">https://www.epa.gov/newsreleases/trump-epa-kicks-formal-reconsideration-endangerment-finding-agency-partners</a>.
---------------------------------------------------------------------------

On July 29, 2025, the Administrator signed a proposed rule setting
out the results of the EPA's reconsideration to date and proposing to
rescind the Endangerment Finding and repeal all GHG emission standards
for LD, MD, and HD new motor vehicles and engines promulgated since
2009 under CAA section 202(a)(1). ``Reconsideration of 2009
Endangerment Finding and Greenhouse Gas Vehicle Standards,'' 90 FR
36288 (Aug. 1, 2025). We proposed that the term ``air pollution'' in
CAA section 202(a)(1) is best read in context as referring to pollution
that threatens public welfare through local or regional exposure,
consistent with historical practice and principles of proximate cause,
such that the EPA's regulatory authority does not extend to global
climate change concerns. Relatedly, we proposed that the major
questions doctrine applies to the question whether the EPA may decide
the Nation's policy response to global climate change concerns and that
Congress did not clearly delegate that decision when it authorized the
Agency to prescribe emission standards for new motor vehicles and
engines. We also proposed that the Endangerment Finding departed from
the statute in additional ways by asserting ``procedural discretion''
to issue findings separately from the required standards and severing
the question whether GHG emissions from motor vehicles and engines
contribute to increases in global GHG concentrations from the question
whether cumulative global GHG concentrations endanger public health and
welfare.
In the alternative, we proposed that the Administrator exercise
discretion under CAA section 202(a)(1) to issue a new finding that the
conclusions reached in the Endangerment Finding

[[Page 7693]]

are not supported by the scientific record, including because the EPA
unreasonably compiled and analyzed the record in 2009 and because
intervening developments have cast significant doubt on the
Endangerment Finding's core premises and assumptions. For example, we
proposed that data from 2009-2024 demonstrate that many of the
predictive analyses relied upon in the Endangerment Finding were overly
pessimistic and underestimated the ability of natural processes to
compensate for the identified trends.
Finally, we proposed three alternative bases to repeal the GHG
emission standards separate and apart from the proposed rescission of
the Endangerment Finding. First, we proposed that there is no
``requisite technology,'' as required for emission standards to go into
effect under CAA section 202(a)(2), that is capable of having a
measurable impact on the global climate change concerns that were the
basis of the Endangerment Finding. Second, we proposed that the
Agency's GHG regulatory program is futile because emissions from
covered vehicles have a de minimis impact on global climate change
concerns and that this consideration bears on the proper interpretation
and implementation of CAA section 202(a)(1). Third, we proposed that
the GHG emission standards harm public health and welfare on balance by
increasing prices and decreasing consumer choice, thereby slowing the
replacement of older vehicles that are less safe and emit a greater
volume and variety of air pollutants. We sought comment on these and
additional issues throughout the proposal, including the EPA's
authority to reconsider and rescind the Endangerment Finding, relevant
data and information bearing on the efficacy of the GHG emission
standards, and any additional reasons we should consider for repealing
or retaining the Endangerment Finding and associated regulations.

C. Summary of Comments and Updates From the Proposal in This Final
Action

This final action is informed by the significant public input
received from a diverse array of stakeholders since publication of the
proposal in the Federal Register on August 1, 2025. The EPA extended
the original comment deadline of September 15, 2025, to September 22,
2025.\18\ To facilitate participation, we held four days of virtual
public hearings on August 19 through August 22, 2025, during which we
heard oral testimony from more than 600 speakers. Consistent with the
EPA's Tribal Consultation Policy, we also invited all federally
recognized Tribes to participate in consultation, which resulted in
four consultation sessions in addition to oral testimony and written
submissions from several federally recognized Tribes and tribal
organizations. For more information on public participation, see the
public hearing, tribal consultation, and meeting summaries available in
the docket for this rulemaking.
---------------------------------------------------------------------------

\18\ 90 FR 39345 (Aug. 15, 2025).
---------------------------------------------------------------------------

The EPA received approximately 572,000 written comments from more
than 31,000 unique entities and 169 mass letter writing campaigns
during the public comment period, including written submissions
received in connection with the public hearing and Tribal consultation
sessions. The EPA considered all input received during the public
comment period in evaluating this final action, and all written
comments, as well as a transcript of the public hearing, are available
in the docket for this rulemaking.\19\ Given the significant volume of
comments received, this preamble includes summaries of relevant
comments in the appropriate subsection, along with summaries of the
EPA's responses. For more detailed descriptions of comments received
and our responses, see the Response to Comments document available in
the docket for this rulemaking.\20\
---------------------------------------------------------------------------

\19\ See 42 U.S.C. 7607(d)(1)(C), (d)(4)(B)(i), (d)(5)-(6). Note
that although all public comments are posted in the docket, the EPA
has not considered or responded separately to comments received
after the close of the comment period on September 22, 2025.
\20\ ``Rescission of the Greenhouse Gas Endangerment Finding and
Motor Vehicle Greenhouse Gas Emission Standards Under the Clean Air
Act: Response to Comments.'' EPA 420-R-26-003. February 2026.
---------------------------------------------------------------------------

1. Issues Raised Regarding the Rulemaking Process
The EPA received comments on rulemaking process, including with
respect to the length of the comment period and the content of the
proposed rule. The EPA notes that most commenters did not raise
concerns with these aspects of the rulemaking process and believes that
the large volume of comments received and extensive participation in
the public hearing demonstrate that interested stakeholders were able
to submit views, data, and information for consideration. Below, we
summarize comments received on the rulemaking process along with our
responses.
Comment: Many commenters appreciated the chance to weigh in on the
underlying science relevant to the Endangerment Finding and regulations
under CAA section 202(a)(1) for the first time since 2009 and asserted
that the rulemaking process allowed ample public participation and was
consistent with statutory requirements.
Response: The EPA appreciates and agrees with these comments. As
discussed in the proposed rule, we believe that public participation on
regulatory issues of this magnitude is essential to good government.
Because we are not finalizing many of the alternative bases for the
proposed rescission and repeals, this final action does not resolve or
substantively respond in full to issues raised in public comments that
are outside the scope of the bases finalized in this action. We look
forward to further engagement on these additional topics in the future.
For further discussion of the alternative bases we are not finalizing,
please see section VI of this preamble and the Response to Comments
document.
Comment: Other commenters argued that we should have provided a
longer comment period, including a comment period of up to six months,
given the scope of this rulemaking and significant public interest in
the underlying issues. Some of these commenters suggested that the
statute requires providing a ``reasonable'' period for public comment.
Others pointed to language in E.O. 12866 providing that ``a meaningful
opportunity to comment on any proposed regulation . . . should include
a comment period of not less than 60 days.''
Response: The EPA disagrees with these comments. The significant
volume of comments received during the comment period, as well as the
number of participants in the four-day public hearing, demonstrate that
the interested public had a reasonable opportunity to participate in
this rulemaking by engaging with the EPA. The public comment period
fully satisfied the CAA's detailed requirements for public
participation. For example, CAA section 307(d)(5) requires that the
Administrator allow ``thirty days after completion of the [public
hearing] to provide an opportunity for submission of rebuttal and
supplementary information,'' \21\ and CAA section 307(h) states the
intent of Congress that the Administrator ``ensure a reasonable period
for public participation of at least 30 days.'' \22\ With respect to
E.O. 12866, we note that the language cited generally tracks the less
detailed rulemaking provisions of the

[[Page 7694]]

Administrative Procedure Act (APA) rather than the specific processes
Congress established as applicable to this rulemaking in CAA section
307(d), and is intended as non-binding, general guidance for agency
rulemakings that yields to more specific statutes and
circumstances.\23\
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\21\ See 42 U.S.C. 7607(d)(5).
\22\ See 42 U.S.C. 7607(h).
\23\ See 58 FR 51735, 51740 (Oct. 4, 1993) (providing that
``each agency should afford the public a meaningful opportunity to
comment on any proposed regulation, which in most cases should
include a comment period of not less than 60 days'') (emphases
added).
---------------------------------------------------------------------------

Comment: Some commenters asserted that the proposed rule was
procedurally flawed under CAA section 307(d)(3) for various reasons,
including the assertion that we should have directly referenced,
summarized, and included in the docket pertinent findings by the
National Academy of Sciences (NAS). These commenters asserted that we
should repropose with additional discussion of NAS materials, which,
they assert, are central to the rulemaking.
Response: The EPA disagrees that the proposal was procedurally
flawed in any manner that impacts this final action. The statement of
basis and purpose included in the proposal satisfied the requirements
of CAA section 307(d)(3)(A)-(C) by including not only the factual data,
methodology, and major legal interpretations and policy considerations
relevant to the proposal, but also a detailed discussion of relevant
factual and legal developments since 2009 impacting the EPA's
reconsideration.\24\ With respect to the NAS, the statute references
only ``pertinent findings, recommendations, and comments'' by the NAS
and discussion of differences from the proposal only when it ``differs
in any important respect.'' \25\ In section IV.B of the preamble to the
proposed rule, we explained that the Administrator had considered the
most recently available scientific information, including assessments
by the U.S. Global Change Research Program (USGCRP) and United Nations
Intergovernmental Panel on Climate Change (IPCC). With respect to
discussion of global climate change concerns, the NAS findings cited by
these commenters or in previous EPA rulemakings rely upon, and are
duplicative of, these assessments.\26\ In other respects, the NAS
findings deal with matters that were not pertinent to the substance of
the proposal, including particular emissions-reduction
technologies,\27\ matters pertaining to criteria pollutant
standards,\28\ and how to utilize Social Cost of Carbon (SCC)
methodologies in an RIA or similar analysis.\29\
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\24\ 42 U.S.C. 7607(d)(3)(A)-(C).
\25\ 42 U.S.C. 7607(d)(3).
\26\ See, e.g., 88 FR 29184, 29208, 29394 (May 5, 2023)
(proposed HD GHG emission standards) (briefly citing NAS findings
together with USGCRP and IPCC reports). To the extent commenters
cited or intended to reference the September 2025 report developed,
published, and submitted by the NAS during the comment period for
the purposes of informing this rulemaking, we note that the
Administrator could not have considered the September 2025 report
when signing the proposal in July 2025.
\27\ See, e.g., 88 FR 29284-86 (discussing NAS findings on
challenges and advantages associated with particular technologies
for reducing vehicle emissions). The EPA notes that none of the
bases finalized in this action, including the futility basis
discussed in section V of this preamble, turn on the relative
advantages of particular technologies in reducing GHG emissions from
vehicles and engines. Rather, we are finalizing that GHG emission
standards under CAA section 202(a)(1) do not have more than a de
minimis impact on the health and welfare dangers identified in the
Endangerment Finding because even the complete elimination of GHG
emissions from new and existing LD, MD, and HD vehicles would not
materially impact GMST or GSLR as a proxy for adverse impacts to
public health and welfare.
\28\ See, e.g., 88 FR 29224 (discussing NAS materials related to
particulate matter, ozone, NO<INF>X</INF>, sulfur oxides
(SO<INF>X</INF>), and hazardous air pollutants). As noted at
proposal, the EPA is not addressing criteria emission standards in
this rulemaking, and incidental co-benefits of GHG emission
standards are not pertinent to the legal bases on which we are
relying in this final action.
\29\ See, e.g., 88 FR 29370-72 (discussing methodologies for
estimating and utilizing SCC). As noted at proposal, the EPA has
consistently viewed criticisms of the SCC methodology as out of
scope because it played no role in the Endangerment Finding and is
not relevant to the statutory standard for regulation under CAA
section 202(a). Moreover, the U.S. Government is no longer using the
SCC methodology for purposes of estimating costs and benefits.
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In any event, commenters did not identify NAS materials pertinent
to the bases on which we are relying in this final action. Whether CAA
section 202(a)(1) authorizes the EPA to regulate in response to global
climate change concerns by prescribing emission standards is a matter
of statutory interpretation, not scientific analysis within the NAS's
purview. As explained in section VI of this preamble, we are not
finalizing the alternative proposal to base the rescission and repeals
on a new finding by the Administrator under CAA section 202(a)(1). We
note that the NAS developed and submitted during the public comment
period for this rulemaking a new report responding to the concerns
underlying the alternative proposal.\30\ This submission and additional
NAS materials regarding the science of climate change are not pertinent
to the bases for this final action, which are legal in nature and rest
on statutory interpretation, application of judicial precedent, and
legal conclusions drawn from modeling generally accepted for purposes
of predicting impacts within the causal framework endorsed by the
Endangerment Finding. As discussed in section V.C of this preamble, the
NAS has expressed approval for and encouraged the development of the
underlying models the EPA is using in this action to evaluate comments
received on futility and reach conclusions about the impact of futility
on the legality of the Endangerment Finding and associated GHG emission
standards.
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\30\ See Comment ID EPA-HQ-OAR-2025-0194-0756, NAS 2025,
``Effects of Human-Caused Greenhouse Gas Emissions on U.S. Climate,
Health, and Welfare.'' Washington, DC: The National Academies Press.
---------------------------------------------------------------------------

Comment: Additionally, some commenters asserted that the proposed
rule should have been made available to the Science Advisory Board
(SAB) before publication. These commenters asserted that SAB input is
centrally relevant to the rulemaking but generally acknowledged that
the EPA did not submit the Endangerment Finding or subsequent
reconsideration denials in 2010 and 2022 to the SAB for prior review.
Response: By statute, the Administrator is to make available to the
SAB ``any proposed criteria document, standard, limitation, or
regulation'' when such material ``is provided to any other Federal
agency for formal review and comment.'' \31\ The proposal for this
rulemaking, which sought comment on rescinding the Endangerment Finding
and related GHG emission standards, was not a ``criteria document,
standard, limitation, or regulation'' that would impose obligations on
the EPA or any regulated entities if finalized. We note that the EPA
used the same interpretation to propose and finalize the Endangerment
Finding, as well as issue the 2010 and 2022 denials of petitions for
reconsideration, without prior SAB review. Whereas those actions
obligated and maintained the obligation for the EPA to issue GHG
emission standards that are subject to SAB review, the actions
contemplated in the proposal would relieve the Agency of the obligation
to maintain and issue regulations with SAB input as well as ongoing
obligations for regulated parties. Nor did we submit the proposal to
``any other Federal agency for formal review and comment.'' The EPA has
previously taken the position that ``formal'' consultation is not
required for CAA section 202(a)(1) actions and that informal
interagency review as part of the non-statutory E.O. 12866 process is

[[Page 7695]]

not encompassed within the statutory term ``formal review and
comment.'' \32\
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\31\ 42 U.S.C. 4365(c)(1).
\32\ See Resp. Br. 75-79, Delta Constr. Co. v. EPA, No. 11-1428
(filed Nov. 24, 2014); Coal. for Responsible Regulation, Inc. v.
EPA, 684 F.3d 102, 124 (D.C. Cir. 2012), reversed in part in UARG,
573 U.S. 302 (noting ``it is not clear that EPA provided the
Endangerment Finding'' to any other agency and that petitioners
failed to respond to the argument).
---------------------------------------------------------------------------

Given the nature of the proposal and the legal bases on which the
EPA relies in this final action, the possibility of SAB review is not
material to the outcome of this rulemaking. Because we conclude that
CAA section 202(a)(1) does not authorize the EPA to regulate in
response to global climate change concerns, this final action does not
turn on scientific findings made with respect to the validity,
certainty, or extent of global climate change. We note that the D.C.
Circuit has previously determined that failing to secure SAB review of
the Endangerment Finding was not ``of such central relevance'' that
there is a ``substantial likelihood'' the action ``would have been
significantly changed'' absent such failure.\33\ Commenters provided no
reason to conclude that SAB review of this rulemaking to rescind the
Endangerment Finding would be of central relevance for the first time,
particularly given the ample recommendations already provided on
previously promulgated GHG emission standards and the legal nature of
the rationales being finalized.
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\33\ Coal. for Responsible Regulation, 684 F.3d at 124 (quoting
42 U.S.C. 7607(d)(8)); see also Am. Petrol. Inst. v. Costle, 665
F.2d 1176, 1188-89 (D.C. Cir. 1981) (similar with respect to ozone
standard not submitted for SAB review).
---------------------------------------------------------------------------

Comment: Finally, commenters offered competing positions on the
EPA's proposal to rescind the 2022 and 2010 denials of petitions for
reconsideration entitled ``Endangerment and Cause or Contribute
Findings for Greenhouse Gases Under Section 202(a) of the Clean Air
Act; Final Action on Petitions,'' 87 FR 25412 (Apr. 29, 2022), and
``EPA's Denial of the Petitions to Reconsider the Endangerment and
Cause or Contribute Finding for Greenhouse Gases Under Section 202(a)
of the Clean Air Act,'' 75 FR 49556 (Aug. 13, 2010).\34\ Supportive
commenters argued that the 2022 and 2010 petitions raised a variety of
valid procedural, legal, scientific, and transparency-related issues
with the Endangerment Finding. Conversely, adverse commenters asserted
that the EPA erred in proposing to rescind the petition denials at the
same time as proposing to rescind the Endangerment Finding, which was
the subject of the petitions for reconsideration. These commenters
argued that we lack authority to rescind a petition denial and provided
insufficient rationale in the proposal to support such a rescission.
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\34\ As noted at proposal, the 2022 petition denials included a
notice of decision in the Federal Register, brief letters
communicating the denials to the petitioners, and a decision
document entitled ``EPA's Denial of Petitions Relating to the
Endangerment and Cause or Contribute Findings for Greenhouse Gases
Under Section 202(a) of the Clean Air Act'' (Apr. 21, 2022) (``2022
Denials''), available online at <a href="https://www.epa.gov/system/files/documents/2022-04/decision_document.pdf">https://www.epa.gov/system/files/documents/2022-04/decision_document.pdf</a>.
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Response: The EPA appreciates the comments received on this issue
and is taking the opportunity to clarify that the 2022 and 2010
reconsideration petition denials no longer represent the Agency's views
and should not be relied upon for any statements inconsistent with this
final action. As explained at proposal, the petition denials already
had no prospective legal effect and were not binding on the EPA or
interested parties. We proposed to rescind the petition denials along
with the Endangerment Finding and associated GHG emission standards to
promote consistency and avoid confusion, as the petition denials relied
in large part on the prior positions in those actions that we proposed
to abandon. In this final action, we are repudiating the EPA's
positions since 2009 to the extent and for the reasons set out in
section V of this preamble. We are also finalizing rescission of the
petition denials because those decisions affirmed the same legal
positions and, moreover, decided scientific questions that are
unnecessary and inappropriate for the Agency to address under CAA
section 202(a)(1). For discussion of the EPA's authority to reconsider
prior actions unless provided otherwise by the governing statute, see
section IV of this preamble.
2. Updates From the Proposal in This Final Action
The EPA received supportive and adverse comments on virtually all
substantive aspects of the proposal from a wide variety of
stakeholders, including vehicle and engine manufacturers and suppliers,
nearly all 50 States and the District of Columbia, elected
representatives at the local, State, and Federal levels (including many
members of the U.S House of Representatives and the U.S. Senate),
consumer and labor groups, EV advocates, manufacturers, and suppliers,
educational institutions, environmental groups, and individual
citizens. With respect to the primary basis for the proposed repeal, we
received detailed comments offering legal arguments for and against our
proposed interpretation of the statute and the applicability and impact
of the major questions doctrine. With respect to the alternative bases
for the proposed repeal, we received extensive data, models, and
arguments on virtually every aspect of climate science and climate
impacts discussed at proposal. Submissions related to the alternative
climate science basis for rescission and repeal in section IV.B of the
preamble to the proposed rule constituted the largest share of public
comments received. Commenters also submitted substantial information in
response to our request for comment on the alternative rationales in
section V of the preamble to the proposed rule, including data and
modeling addressing the historical and potential impacts of GHG
emission standards under CAA section 202(a)(1) on the global climate
change concerns animating the Endangerment Finding, such as trends in
GMST and GSLR.
The EPA is finalizing the primary basis for the rescission and
repeals as proposed for the reasons stated in section V of this
preamble. We conclude that the best reading of the statute does not
authorize the EPA to prescribe GHG emission standards based on global
climate change concerns and, moreover, that EPA erred in issuing the
Endangerment Finding as a standalone action that severed the
consideration of endangerment from the consideration of contribution
and failed to engage with the standards that must issue when making
such a finding. We further conclude, as proposed, that the major
questions doctrine applies and bars the EPA from asserting the
authority to decide the Nation's policy response to global climate
change concerns, including by attempting to force a shift to EVs, based
on language authorizing the Agency to prescribe emission standards.
Finally, we conclude that the inability of GHG emission standards under
CAA section 202(a)(1) to measurably impact the global climate change
concerns identified in the Endangerment Finding further supports our
interpretation of the statute and provides an additional reason to
repeal the GHG emission standards.
In light of these conclusions, and as discussed further in section
VI of this preamble, the EPA is not finalizing the alternative proposed
bases for rescission and repeal. The robust public response to the
alternative climate science basis revealed ongoing disagreement among
commenters with respect to aspects of the scientific analysis
underpinning the Endangerment Finding, including the certainty of the
causal chain, the extent of endangerment attributable to U.S. new motor
vehicle and engine

[[Page 7696]]

emissions, the countervailing domestic benefits of global climate
change, and the capacity of natural and human systems to adapt and
mitigate potential adverse impacts and the relevance of such topics to
the analysis. However, we conclude that the EPA lacks statutory
authority to regulate GHG emissions from new motor vehicles and engines
in the first instance under CAA section 202(a)(1). Accordingly,
although the Administrator continues to harbor concerns regarding the
scientific determinations underlying the 2009 Endangerment Finding, we
cannot resolve these questions under our regulatory authority in CAA
section 202(a)(1), and comments received on these subjects are outside
the scope of this final action. Similarly, the EPA's lack of authority
to regulate GHG emissions from new motor vehicles and engines places
comments on the alternative bases for repealing the standards--
including the ``requisite technology'' requirement in CAA section
202(a)(2) and additional factors relative to standards-setting--outside
the scope of this final action.
This final action removes all existing regulations that require new
motor vehicle and engine manufacturers to measure, report, or comply
with GHG emission standards. Specifically, the EPA is removing
regulations in 40 CFR parts 85, 86, 600, 1036, and 1037 pertaining to
the control of GHG emissions from LD, MD, and HD new motor vehicles and
engines, including emission standards; test procedures; averaging,
banking, and trading (ABT) requirements; reporting requirements; and
fleet-average emission requirements.\35\ As a result of these changes,
motor vehicle and engine manufacturers no longer have future or current
obligations for the measurement, control, or reporting of GHG emissions
for any vehicle or engine, including for previously manufactured MYs.
However, we did not reopen or modify any regulations necessary for
criteria pollutant and air toxic measurement and standards, Corporate
Average Fuel Economy (CAFE) testing, and associated fuel economy
labeling requirements.
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\35\ ``Light-Duty Vehicle Greenhouse Gas Emission Standards and
Corporate Average Fuel Economy Standards,'' 75 FR 25324 (May 7,
2010); ``Greenhouse Gas Emissions Standards and Fuel Efficiency
Standards for Medium- and Heavy-Duty Engines and Vehicles,'' 76 FR
57106 (Sept. 15, 2011); ``2017 and Later Model Year Light-Duty
Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy
Standards,'' 77 FR 62624 (Oct. 15, 2012); ``Greenhouse Gas Emissions
and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and
Vehicles-Phase 2,'' 81 FR 73478 (Oct. 25, 2016); ``The Safer
Affordable Fuel-Efficient (SAFE) Vehicles Rule for Model Years 2021-
2026 Passenger Cars and Light Trucks,'' 85 FR 24174 (Apr. 30, 2020);
``Revised 2023 and Later Model Year Light-Duty Vehicle Greenhouse
Gas Emissions Standards,'' 86 FR 74434 (Dec. 30, 2021); ``Multi-
Pollutant Emissions Standards for Model Years 2027 and Later Light-
Duty and Medium-Duty Vehicles,'' 89 FR 27842 (Apr. 18, 2024) (2024
LD and MD Multi-Pollutant Emission Standards Rule); ``Greenhouse Gas
Emissions Standards for Heavy-Duty Vehicles-Phase 3,'' 89 FR 29440
(Apr. 22, 2024) (2024 HD GHG Emission Standards Rule).
---------------------------------------------------------------------------

The EPA received comments from stakeholders related to the proposed
revisions to the engine and vehicle GHG regulations. In general, we are
finalizing the vast majority of the proposed regulatory changes for LD
and MD engines and vehicles. For HD engines and vehicles, we are
removing the GHG emission standards and related certification and
compliance procedures, as proposed. However, in a change from the
proposal, we are retaining the test procedures and compliance
regulatory elements in the EPA regulations referenced by NHTSA in their
regulatory program such that NHTSA can continue to implement its HD
fuel efficiency program. Relevant comments and our responses are
summarized in section VII of this preamble and the Response to Comments
document accompanying this final action.
The EPA also received comments on our analyses included in the
Draft Regulatory Impact Analysis (DRIA). A summary of these comments
and the EPA's responses is included in the Response to Comments
document accompanying this final action. The EPA made a number of
updates to the analyses included in the final RIA, which is available
in the docket for this rulemaking.

III. Background

A. The EPA's Historical Approach to CAA Section 202(a)(1)

Congress originally enacted the language that became CAA section
202(a)(1) as part of the Motor Vehicle Pollution Control Act of 1965,
which required the Secretary of Health, Education, and Welfare to
``prescribe . . . standards, applicable to the emission of any kind of
substance, from any class or classes of new motor vehicles or new motor
vehicle engines, which in his judgment cause or contribute to, or are
likely to cause or contribute to, air pollution which endangers the
health or welfare of any persons.'' \36\ Congress retained this
language, while adding additional requirements for the content of
emission standards, in the Air Quality Act of 1967,\37\ and, later,
incorporated it into the Clean Air Act of 1970, which transferred the
Secretary's regulatory authority to the newly created EPA and directed
the Agency to issue standards that achieved significant reductions in
certain criteria pollutants in the near-term.\38\ Separately, the 1970
CAA addressed emissions from existing vehicles and engines, stationary
sources, and aircraft engines.\39\ In the following decades, Congress
repeatedly amended CAA section 202 to specify particular regulatory
goals and to require the EPA to regulate certain pollutants. Some of
these provisions instructed the EPA to use CAA section 202(a)(1) in
particular ways, while others separately directed the regulation of
specified classes of vehicles or engines or specified air pollutants.
As subsequently amended,\40\ CAA section 202 has remained a critical
part of the comprehensive national framework for regulating air
pollution, with Title II authorities for mobile sources working in
tandem with the National Ambient Air Quality Standards (NAAQS) program
and Title I authorities for stationary sources.\41\ Emission standards
issued under CAA section 202 trigger requirements and enforcement
mechanisms that can impose substantial liabilities on manufacturers and
other regulated parties. Additional provisions in Title II prohibit
selling, importing, or marketing vehicles and engines not in compliance
with applicable emission standards, with violations subject to
injunctive relief and significant monetary penalties.\42\
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\36\ Public Law 89-272, section 202(a), 79 Stat. 992, 992-93
(1965).
\37\ Public Law 90-148, section 202(a), 81 Stat. 485, 499
(1967).
\38\ Public Law 91-604, 84 Stat. 1690 (1970).
\39\ Id.
\40\ In the CAA Amendments of 1977, Congress replaced the phrase
``which endangers the public health or welfare'' with ``which may
reasonably be anticipated to endanger public health or welfare.''
Public Law 95-95, section 401(d)(1), 91 Stat. 685, 791 (1977);
Public Law 101-549, section 203, 104 Stat. 2399, 2474 (1990).
\41\ See West Virginia, 597 U.S. at 707-11 (describing the
relationship among the CAA's Title I programs).
\42\ 42 U.S.C. 7522-24. By regulation, the EPA has established a
number of compliance and enforcement mechanisms specific to
particular emission standards regimes, including GHG emission
standards. For example, we have adopted a credit system whereby
regulated parties that do not achieve the standards for a particular
MY may carry forward a deficit for a certain number of years,
provided that the entity overcomply in future years or purchase
credits to make up for the prior shortfall. 40 CFR 86.1865-12.
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In its first four decades administering the statute, the EPA
invoked CAA section 202(a)(1) relatively infrequently and, in each
case, to address local and regional air pollution problems through
rulemakings that both prescribed

[[Page 7697]]

standards and set forth the Administrator's findings that the relevant
air pollutant emissions cause, or contribute to, air pollution which
may reasonably be anticipated to endanger public health or welfare.\43\
From 1965 to 2009, we invoked CAA section 202(a)(1) in at least fifteen
final rules governing LD, MD, and HD vehicle and engine and motorcycle
emissions of hydrocarbons (HC) and other volatile organic compounds
(VOCs), carbon monoxide (CO), oxides of nitrogen (NO<INF>X</INF>),
particulate matter (PM), and certain air toxics.\44\ Where possible, we
relied in these final rules on more specific authorities provided
elsewhere in CAA section 202, including subsections (a)(3)(B)-(D) for
HD vehicles, (a)(3)(E) for motorcycles, and (l) for air toxics. Each of
these regulations involved criteria pollutants or compounds that
Congress expressly enumerated in CAA section 202 through iterative
statutory amendments and addressed in additional provisions throughout
the statute.\45\ We hewed closely to the vehicle and engine emission
air pollution problems that Congress itself identified and did not use
CAA section 202(a)(1) to expand into new regulatory arenas. As further
explained in the following subsections, the EPA maintained this
approach until 2009 and never invoked CAA section 202(a)(1) to regulate
in response to global climate change concerns during this period.
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\43\ See 74 FR 66501, 66527, 66538, 66543 (Dec. 15, 2009)
(acknowledging this regulatory history).
\44\ See 72 FR 8428 (Feb. 26, 2007); 69 FR 2398 (Jan. 15, 2004);
66 FR 5002 (Jan. 18, 2001); 65 FR 59896 (Oct. 6, 2000); 65 FR 6698
(Feb. 10, 2000); 62 FR 54694 (Oct. 21, 1997); 62 FR 31192 (June 6,
1997); 60 FR 34326 (June 30, 1995); 60 FR 4712 (Jan. 24, 1995); 59
FR 48472 (Sept. 21, 1994); 59 FR 16262 (Apr. 6, 1994); 53 FR 43870
(Oct. 31, 1988); 49 FR 3010 (Jan. 24, 1984); 48 FR 48598 (Oct. 19,
1983); 45 FR 63734 (Sept. 25, 1980).
\45\ See Public Law 101-549, section 203, 104 Stat. 2399, 2474
(1990); Public Law 91-604, section 6, 84 Stat. 1676, 1690 (1970).
---------------------------------------------------------------------------

B. Petitions for Rulemaking and Massachusetts v. EPA

In October 1999, a coalition of 19 environmental organizations
petitioned the EPA to regulate the emission of four GHGs--
CO<INF>2</INF>, methane, N<INF>2</INF>O, and HFCs--from new motor
vehicles and engines under CAA section 202(a)(1). Petitioners claimed
that these four GHGs were ``air pollutant[s]'' under CAA section
302(g), significantly contributed to global climate change, and met the
statutory standard for regulation under CAA section 202(a)(1). Thus,
petitioners claimed that the EPA had the authority and obligation to
find that GHG emissions from new motor vehicles and engines cause, or
contribute to, air pollution which may reasonably be anticipated to
endanger public health or welfare and to prescribe standards in
response.
In September 2003, after receiving and responding to nearly 50,000
public comments on the relevant issues, the EPA denied the 1999
petitions in a final action titled ``Control of Emissions from New
Highway Vehicles and Engines,'' 68 FR 52922 (Sept. 8, 2003) (``2003
Denial''). The 2003 Denial asserted three primary reasons for denying
the petitions. First, after ``examin[ing] the fundamental issue of
whether the CAA authorizes the imposition of control requirements'' to
``reduce the risk of global climate change,'' we concluded that
``CO<INF>2</INF> and other GHGs cannot be considered `air pollutants'
subject to the CAA's regulatory provisions for any contribution they
may make to global climate change.'' 68 FR 52925. Citing the Supreme
Court's decision in FDA v. Brown & Williamson Tobacco Corp., 529 U.S.
120 (2000), we noted that the CAA does not address GHGs as a regulatory
matter, including in then-recent amendments, and that the ``EPA has
used these provisions to address air pollution problems that occur
primarily at ground level or near the surface of the earth.'' 68 FR
52926. On this basis, we concluded that GHGs ``are not air pollutants
under the CAA's regulatory provisions, including sections 108, 109,
111, 112, and 202'' because they categorically are not ``air
pollutant[s]'' under the Act-wide definition in CAA section 302(g). 68
FR 52928. Second, we raised in the alternative several policy reasons
for declining to regulate GHGs, including that regulating GHG emissions
from motor vehicles and engines under the CAA would interfere with
NHTSA's authority to implement fuel economy standards. 68 FR 52929. We
also asserted that regulating GHG emissions from motor vehicle engines
under the CAA would undermine then-President Bush's policy approach of
addressing global climate change concerns comprehensively through
voluntary actions and incentives, the promotion of research and
technologies, and international negotiations. 68 FR 52930-31. That is,
we reasoned that establishing GHG emission standards through unilateral
action would ``result in an inefficient, piecemeal approach to
addressing the climate change issue'' because ``all significant sources
and sinks of GHG emissions'' should be considered in deciding the best
way to achieve emissions reductions. 68 FR 52931.
In Massachusetts, the Supreme Court narrowly reversed the D.C.
Circuit's decision upholding the EPA's denial of the 1999 petitions for
rulemaking.\46\ The Court took particular issue with the EPA's reading
of the Act-wide definition in CAA section 302(g), ruling that ``[t]he
Clean Air Act's sweeping definition of `air pollutant' . . . embraces
all airborne compounds of whatever stripe'' and provided no textual
basis for excluding CO<INF>2</INF> or the three other GHGs raised in
the petitions for rulemaking. 549 U.S. at 528-29. The Court also
addressed the EPA's reliance on Brown & Williamson, which the majority
construed as having found no congressional intent to ban the sale of
tobacco products outright because such an application of the relevant
statute would have been highly unlikely and because the Food and Drug
Administration (FDA) had expressly refused to assert such authority in
the past. Id. at 530-31. In contrast, in Massachusetts, the Court found
that the CAA did not reflect a congressional intent to categorically
exclude GHGs and, citing several EPA memoranda, that we had not
similarly foresworn all authority to regulate GHGs as a categorical
matter. Id.
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\46\ The D.C. Circuit majority had upheld the denial on the
merits because ``the EPA Administrator properly exercised his
discretion under section 202(a)(1) in denying the petition for
rulemaking.'' Massachusetts v. EPA, 415 F.3d 50, 58 (D.C. Cir.
2005). The dissent argued that CAA section 202(a)'s breadth provided
the EPA sufficient authority to regulate GHGs, that more specific
authorization was not required, and that the EPA's policy
justifications were inadequate reasons to deny the petitions. Id. at
67-82 (Tatel, J., dissenting).
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Notably, the Court expressly declined to decide whether the EPA was
required to issue an endangerment finding as to GHG emissions under the
standard set out in CAA section 202(a)(1). Id. at 534 (``We need not
and do not reach the question whether on remand EPA must make an
endangerment finding.''). Nor did the Court address ``whether policy
concerns can inform EPA's actions in the event that it makes such a
finding.'' Id. at 534-35. Rather, the Court emphasized that the scope
of its review of the denial of a rulemaking petition was ``extremely
limited,'' id. at 527-28 (citation omitted), and held that we must
respond to the petitions by deciding whether GHG emissions from new
motor vehicles and engines meet the standard for regulation in CAA
section 202(a)(1) or whether the science was too uncertain to make any
determination, and that, in doing so, we must ``ground [our] reasons
for action or inaction in the statute,'' id. at 535.\47\
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\47\ Writing for four members of the Court, Chief Justice
Roberts would have dismissed the petitions for review for lack of
Article III standing. 549 U.S. at 535 (Roberts, C.J., joined by
Scalia, Thomas, and Alito, J.J., dissenting). Writing for the same
four members of the Court, Justice Scalia would have denied the
petitions on the grounds that the Administrator reasonably exercised
judgment in declining to regulate and that CAA section 302(g)'s
definition of ``air pollutant'' does not clearly encompass
CO<INF>2</INF> and other GHGs that naturally occur in the ambient
air. 549 U.S. at 549 (Scalia, J., joined by Roberts, C.J., and
Thomas and Alito, J.J., dissenting).

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[[Page 7698]]

C. The 2009 Endangerment Finding

The EPA responded to the Supreme Court's decision in Massachusetts
by issuing the 2008 ANPRM. In the 2008 ANPRM, the Administrator began
by noting it was ``clear that if EPA were to regulate [GHG] emissions
from motor vehicles under the Clean Air Act,'' the interplay between
CAA section 202(a)(1) and similarly worded statutory provisions ``could
result in an unprecedented expansion of EPA authority that would have a
profound effect on virtually every sector of the economy and touch
every household in the land.'' 73 FR 44355. The Administrator cautioned
that because the CAA was ``originally enacted to control regional
pollutants that cause direct health effects,'' invoking authority to
regulate GHG emissions ``would inevitably result in a very complicated,
time-consuming, and, likely, convoluted set of regulations'' that
``would be relatively ineffective at reducing [GHG] concentrations''
and have a ``potentially damaging effect on jobs and the U.S.
economy.'' Id.
The 2008 ANPRM echoed the Administrator's concerns by seeking
public comment on invoking CAA section 202(a)(1) to regulate new motor
vehicle and engine emissions in response to global climate change
concerns. We acknowledged that the CAA ``was not specifically designed
to address GHGs,'' 73 FR 44397, and that the EPA had historically
interpreted and applied its CAA regulatory authorities as extending to
local and regional air pollution problems, 73 FR 44408. We further
noted that Congress was considering legislation to address the Nation's
response to global climate change concerns and that, since
Massachusetts, Congress had passed and the President had signed into
law the Energy Independence and Security Act (EISA),\48\ which amended
provisions applicable to the EPA's Renewable Fuels Standard (RFS)
program and NHTSA's CAFE standards program. 73 FR 44398. Finally, we
noted that the EPA received additional petitions to regulate stationary
sources and additional GHGs, including water vapor, all of which
suggested that GHG emission regulations could not readily be limited to
new motor vehicles and engines. 73 FR 44399 & n.26.
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\48\ Public Law 110-140, 121 Stat. 1492 (2007).
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As to CAA section 202(a)(1), the 2008 ANPRM set out a framework for
determining whether ``GHG emissions from new motor vehicles cause or
contribute to air pollution that may reasonably be anticipated to
endanger public welfare'' under CAA section 202(a)(1) or for
``explain[ing] why scientific uncertainty is so profound that it
prevents making a reasoned judgment on such a determination.'' 73 FR
44398, 44421. We reviewed available information for CO<INF>2</INF>,
methane, and N<INF>2</INF>O emissions and noted that HFCs, PFCs, and
SF<INF>6</INF> are ``often grouped together'' and separately from the
rest ``because they contain fluorine, typically have large global
warming potentials, and are produced only through human activities.''
73 FR 44401-02.\49\ With respect to endangerment, we sought comment on
whether GHGs could properly be considered air pollution that endangers
public health or welfare because the potential health effects are
indirect and the potential welfare effects may be positive on balance.
73 FR 44427. In addition, we sought comment on whether ``the unique
characteristics and properties of each GHG . . . as well as current and
projected emissions'' meant that each GHG should be analyzed
individually or whether certain GHGs other than CO<INF>2</INF> were
amenable to grouping. 73 FR 44428. With respect to causation or
contribution, we presented motor vehicle and engine emissions data for
each GHG separately and noted that emission trends had diverged between
pollutants, with CO<INF>2</INF> emissions, for example, generally
increasing since 1990 and N<INF>2</INF>O emissions, for example,
increasing from 1990 to 1995 and then falling substantially from 1995
to 2006 because of fuel and technology changes. 73 FR 44430. We also
presented extensive information on potential regulatory approaches that
could be triggered by a positive finding under CAA section 202(a)(1),
including approaches specific to particular GHGs. 73 FR 44438-63.
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\49\ In the 2008 ANPRM, the EPA noted that the most recently
available IPCC analysis concluded that ``[t]he anthropogenic
combined heating effect (referred to as forcing) of [methane],
N<INF>2</INF>O, HFCs, PFCs and SF<INF>6</INF> is about 40% as large
as the CO<INF>2</INF> cumulative heating effect since pre-industrial
times.'' 73 FR 44423.
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Following a change in administration, however, the EPA proposed in
April 2009 and finalized in December 2009 a much different approach to
analyzing GHG emissions from new motor vehicles and engines under CAA
section 202(a)(1). In the Endangerment Finding, the Administrator found
that ``the science [was] sufficiently certain'' to compel a
determination and interpreted Massachusetts as ``allow[ing] for the
consideration only of science.'' 74 FR 66501. The Administrator
interpreted Massachusetts as holding not only that ``GHGs fall within
the definition of `air pollutant' under the CAA,'' but also as standing
for the proposition ``that EPA may regulate GHGs if required findings
were made.'' EF RTC 11:5. While expressing a ``preference for
comprehensive climate change legislation over the use of the current
CAA to tackle climate change,'' the Administrator understood the
Endangerment Finding as satisfying the EPA's ``duty'' and
``responsibility to respond to the Supreme Court's decision and to
fulfill its obligations under current law.'' EF RTC 11:19.\50\ In
addition, the Administrator declined to consider any of the
implementation challenges or options discussed in the 2008 ANPRM,
asserting instead that CAA section 202(a) confers ``procedural
discretion'' to issue standalone findings without considering a
regulatory response because the statute ``is silent on this issue,'' 74
FR 66501, and interpreting Massachusetts as forbidding the EPA from
considering in any respect the regulations that will result from an
affirmative finding, 74 FR 66515.
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\50\ Specifically, a variety of commenters on the proposed
Endangerment Finding asserted that the Clean Air Act is ill-suited
to address global climate change concerns, and that the EPA should
await the results of ongoing debates and development of responsive
legislation in Congress, for which both the President and the
Administrator had expressed support. EF RTC 11:18-19.
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The Administrator defined the relevant ``air pollution'' as ``the
combined mix of six key directly-emitted, long-lived and well-mixed
[GHGs] . . . which together, constitute the root cause of human-induced
climate change and the resulting impacts on public health and
welfare.'' 74 FR 66517. At times, the Administrator referred to the
``air pollution'' as the total concentration of GHGs in the atmosphere,
e.g., id., and at times as only the ``elevated atmospheric
concentrations'' of GHGs in the atmosphere as compared to pre-
industrial levels, e.g., 74 FR 66523. In defining ``air pollution'' in
this manner, the Administrator rejected arguments that the term as used
in CAA section 202(a)(1) is limited to domestic concerns and airborne
materials that cause direct human health effects, such as through
inhalation. EF RTC 9:1-2. The Administrator reasoned that the treatment
of ``air pollutant'' in

[[Page 7699]]

Massachusetts extended to the term ``air pollution'' directly, without
the need for analysis of the difference in terminology and statutory
context, and did not specifically grapple with the EPA's prior
practice. Id. Notably, the Administrator excluded other ``climate
forcers'' from this definition, including black carbon, ozone-depleting
substances, nitrogen trifluoride, water vapor, and ground-level ozone.
74 FR 66520. While maintaining that these ``climate forcers'' could be
regulated in response to global climate change concerns, the
Administrator found that these substances were sufficiently different
from the six ``well-mixed'' GHGs to warrant separate consideration. Id.
As to water vapor, the Administrator reasoned that ``the level of
understanding is low'' and that the EPA ``plans to further evaluate the
issues of emissions of water.'' Id. And as to ground-level ozone, the
Administrator reasoned that although ``tropospheric ozone
concentrations have exerted a significant anthropogenic warming effect
since pre-industrial times,'' ozone was unlike the six directly
emitted, ``well-mixed'' GHGs because it ``forms in the atmosphere from
emission of pre-cursor gases.'' Id.
The Administrator also defined the relevant ``air pollutant'' as
``a single air pollutant'' comprised of ``the same six long-lived and
directly-emitted [GHGs],'' meaning the Endangerment Finding did not
need to address the different characteristics or emission trends of any
of the six selected GHGs individually. 74 FR 66536-37. The
Administrator stated that ``if in the future other substances are shown
to meet the same criteria they may be added to the definition of this
single air pollutant'' for regulatory purposes. 74 FR 66537. Although
new motor vehicles and engines ``do not emit all of the substances
meeting the definition of well-mixed [GHGs]''--specifically, PFCs and
SF<INF>6</INF>--the Administrator found that ``the reasonableness of
this grouping does not turn on the particular source category being
evaluated in a contribution finding.'' Id.
With respect to endangerment, the Administrator began by excluding
adaptation--human responses that reduce potential adverse impacts--and
mitigation--independent measures that reduce the causes of potential
adverse impacts--from the analysis of global climate change concerns.
74 FR 66513. The Administrator acknowledged that ``some level of
autonomous adaptation will occur'' and that ``this separation means
this approach may not reflect the actual conditions in the real world
in the future, because adaptation and/or mitigation may occur and
change the risks.'' Id. Nevertheless, the Administrator reasoned that
``it would be extremely hard to make a reasoned projection of human and
societal adaptation and mitigation responses'' because they are
``largely political'' or ``individual personal judgments.'' Id. Next,
the Administrator relied on IPCC Assessment Report 4 (AR4) projections
to find that GMST would likely increase between 1.8 to 4 [deg]C by
2100, with an uncertainty range of 1.1 to 6.4 [deg]C. 74 FR 66519.
Operating within this analytical framework, the Administrator found
that elevated global concentrations of GHGs from all foreign and
domestic sources were responsible for increased GMST that were
responsible in turn for indirect health risks driven by (1) more
frequent heat waves; (2) air quality effects, including increased
formation of ozone, and (3) broader societal impacts related to
increased frequency and severity of certain extreme weather events. 74
FR 66525.\51\ The Administrator also found that GHG emissions could
lead to welfare effects related to GSLR and other downstream impacts,
including (1) food production and agriculture; (2) forestry; (3) water
resources; and (4) energy infrastructure and settlements, although the
evidence was uncertain for several categories that may see near-term
benefits. 74 FR 66531-35.\52\ Importantly, the Administrator
acknowledged that the understanding of public health and welfare in the
Endangerment Finding was atypical, particularly with respect to
considering indirect effects and because ``[n]one of th[e] human health
effects are associated with direct exposure to [GHGs],'' but asserted
the approach was necessary given the ``unique'' challenge presented by
global climate change. 74 FR 66527. The Administrator reasoned that
many of the identified welfare impacts could be considered health
impacts and that all such impacts could result indirectly from GHG
``air pollution,'' 74 FR 66528-29, and noted that the identified
welfare impact pathways involved multiple causal steps, 74 FR
66531.\53\ In reaching these conclusions, the Administrator rejected
arguments that the endangerment analysis should focus on domestic
emissions and impacts on domestic ambient air and that Congress
expressly provided authority when it intended the EPA to consider non-
domestic air pollution. EF RTC 9:1.\54\
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\51\ The Administrator also noted that increased GMST could lead
to changes in certain food- and water-borne pathogens and allergens
(including increases in pollen resulting from increased plant growth
at higher concentrations of CO<INF>2</INF>) but did ``not plac[e]
primary weight on these factors.'' 74 FR 66498, 66526.
\52\ The Administrator relied on welfare impacts to water
resources and sea level rise as providing ``the clearest and
strongest support for an endangerment finding.'' 74 FR 66534.
\53\ The Administrator noted that ``[a]s with public health,''
the analysis of ``welfare'' in the Endangerment Finding ``considered
the multiple pathways'' through which ``the GHG air pollution''
could result in ``climate change'' that ``affects climate-sensitive
sectors,'' which then leads to potential ``impact . . . on public
welfare.'' 74 FR 66531.
\54\ For example, commenters on the proposed Endangerment
Finding pointed to CAA sections 115 (authorizing the EPA to require
controls when domestic emissions cause or contribute to air
pollution that endangers public health or welfare in another country
that has adopted reciprocal protections for emissions into the
United States), 179B (authorizing the EPA to account for the impact
of international emissions on State attainment of the NAAQS under
certain conditions), and Title VI (providing for various authorities
and obligations to address emissions that damage the ozone layer).
EF RTC 9:1; see 42 U.S.C. 7415, 7509a, 7671 et seq.
---------------------------------------------------------------------------

With respect to contribution, the Administrator asserted broad
authority to interpret the statutory standard because ``[t]he language
of CAA section 202(a) is silent regarding how the Administrator is to
make her contribution analysis.'' 74 FR 66544. Exercising that putative
interpretive authority, the Administrator concluded that ``it is
reasonable to consider that lower percentages contribute than one may
consider when looking at a local or regional problem involving fewer
sources of emissions,'' 74 FR 66545, because ``all contributors must do
their part'' to avoid ``a tragedy of the commons, whereby no country or
source category would be accountable for contributing to the global
problem of climate change,'' 74 FR 66543. Next, the Administrator
relied on data showing that existing motor vehicles and engines emitted
four GHGs--CO<INF>2</INF>, methane, and N<INF>2</INF>O from engines, as
well as HFCs from air conditioning units--that accounted for 4.3
percent of annual global GHG emissions at the time. On that basis, the
Administrator found that annual GHG emissions from new motor vehicles
and engines ``contribute to the air pollution'' consisting of the total
global concentrations of the six ``well-mixed'' GHGs previously
identified as a danger to public health or welfare. 74 FR 66537-39.
Crucially, the Endangerment Finding made clear that the EPA was
acting independently from any new congressional mandate. Rather, the
Administrator interpreted CAA section 202(a)(1) as setting out a
standalone authority to issue findings that establish an obligation to
regulate without considering implementation and purported to rest the
Endangerment Finding solely on a scientific judgment

[[Page 7700]]

informed by the record as assembled by the Agency in 2009.

D. Implementation of the 2009 Endangerment Finding

In the years since issuing the Endangerment Finding, the EPA has
promulgated GHG emission standards for various classes of new motor
vehicles and engines in reliance on the Endangerment Finding and, as
anticipated in the 2008 ANPRM, sought to expand the same analytical
framework to regulatory provisions governing existing vehicles,
stationary sources, aircraft, and oil and gas operations. For a full
accounting of GHG emission standards adopted since 2009 under CAA
section 202(a)(1), see sections VII.B and VII.C of this preamble.
In the Endangerment Finding, the EPA treated as out of scope the
impacts of extending CAA section 202(a)(1) to address global climate
change concerns on other CAA provisions with similar endangerment
provisions. See, e.g., EF RTC 11:20-23. However, the EPA soon finalized
the first set of GHG emission standards for new motor vehicles and
engines \55\ alongside related rules establishing GHG emission
thresholds for stationary source permitting under the Prevention of
Significant Deterioration (PSD) program and Title V.\56\ Several years
later, the EPA again relied on the Endangerment Finding to extend the
GHG regulatory program to new and existing stationary source
performance standards and guidelines for power plants under CAA section
111.\57\
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\55\ 75 FR 25324 (May 7, 2010).
\56\ ``Reconsideration of Interpretation of Regulations That
Determine Pollutants Covered by Clean Air Act Permitting Programs,''
75 FR 17004 (Apr. 2, 2010) (``Triggering Rule''); ``Prevention of
Significant Deterioration and Title V Greenhouse Gas Tailoring
Rule,'' 75 FR 31514 (June 3, 2010) (``Tailoring Rule'').
\57\ ``Standards of Performance for Greenhouse Gas Emissions
From New, Modified, and Reconstructed Stationary Sources: Electric
Utility Generating Units,'' 80 FR 64510 (Oct. 23, 2015) (``2015
NSPS''); ``Carbon Pollution Emission Guidelines for Existing
Stationary Sources: Electric Utility Generating Units,'' 80 FR 64662
(Oct. 23, 2015) (``Clean Power Plan''). The EPA also cited the
Endangerment Finding to reach a similar conclusion for aircraft
under CAA section 231. ``Finding That Greenhouse Gas Emissions From
Aircraft Cause or Contribute to Air Pollution That May Reasonably Be
Anticipated To Endanger Public Health and Welfare,'' 81 FR 54422
(Aug. 15, 2016).
---------------------------------------------------------------------------

In Coalition for Responsible Regulation, the D.C. Circuit rejected
petitions for review of the Tailpipe Rule, Triggering Rule, Tailoring
Rule, and the underlying Endangerment Finding. As relevant here, the
court read Massachusetts as precluding us from declining to regulate
for policy reasons that ``were not part of the calculus'' and, citing
generally to the entirety of the Massachusetts decision, as holding
that the ``EPA indeed wields the authority to regulate greenhouse gases
under the CAA.'' 684 F.3d at 118. Applying this reading, the court
rejected petitioners' arguments that we should have considered the ```
absurd' '' results for stationary source permitting when issuing the
Endangerment Finding. Id. The court understood the interpretation of
the statutory definition of ``air pollutant'' in Massachusetts to apply
anywhere that term is used in the substantive provisions of the CAA.
Id. at 134-44. The court acknowledged that ``nothing in the CAA
requires regulation of a substance simply because it qualifies as an
`air pollutant' under this broad definition.'' Id. at 135. Applying its
understanding of Massachusetts, however, the court held that reading
``air pollutant'' as ``any regulated air pollutant'' was ``compelled by
the statute'' and rejected petitioners' arguments that the PSD
provisions should be read in context as focusing on localized ``air
pollution'' problems. Id. at 134, 138.\58\
---------------------------------------------------------------------------

\58\ The D.C. Circuit subsequently denied rehearing en banc. See
Coal. for Responsible Regulation v. EPA, 2012 U.S. App. LEXIS 25997
(Dec. 20, 2012). Judge Brown dissented, arguing that the CAA was
designed to address ``the harmful effects of poisoned air on human
beings and their local environs,'' that such important policy
decisions were for Congress to decide, and that the panel had
overread ``dicta'' in Massachusetts. Id. at * 29-62. Then-Judge
Kavanaugh also dissented, arguing that we exceeded our statutory
authority in regulating GHG emissions under the PSD program by
failing to read the term ``air pollutant'' in context and that the
issue was ``plainly one of exceptional importance'' that Congress
should decide. Id. at * 62-93.
---------------------------------------------------------------------------

In UARG, the Supreme Court held that the EPA exceeded its authority
under the CAA in its approach to extending stationary source permitting
to cover GHG emissions. The Court rejected the D.C. Circuit's
application of Massachusetts in this context as a ``flawed syllogism,''
573 U.S. at 316, holding that ``while Massachusetts rejected EPA's
categorical contention that greenhouse gases could not be `air
pollutants' for any purposes of the Act, it did not embrace EPA's
current, equally categorical position that greenhouse gases must be air
pollutants for all purposes regardless of the statutory context,'' id.
at 319 (cleaned up). Rather, ``Massachusetts does not foreclose the
Agency's use of statutory context to infer that certain of the Act's
provisions use `air pollutant' to denote not every conceivable airborne
substance, but only those that may sensibly be encompassed within the
particular regulatory program.'' Id. The Court went on to reject our
interpretation that required a permit based on GHG emissions as ```
incompatible' with `the substance of Congress' regulatory scheme' ''
and inconsistent with the principle that ``Congress . . . speak[s]
clearly if it wishes to assign to an agency decisions of vast `economic
and political significance.' '' Id. at 322-24 (quoting Brown &
Williamson, 529 U.S. at 156, 159).\59\
---------------------------------------------------------------------------

\59\ Writing for four Justices in a partial dissent, Justice
Breyer argued that the statute could be interpreted to encompass
certain stationary sources based on their volume of GHG emissions.
573 U.S. at 334-43 (Breyer, J., joined by Ginsburg, Sotomayor, and
Kagan, J.J.). Writing for two Justices in a partial dissent from a
different holding, Justice Alito argued that the case demonstrated
that Massachusetts was wrongly decided and that the majority erred
in holding that permitted sources that emit conventional pollutants
could be required to install control technologies for GHGs. Id. at
343-50 (Alito, J., joined by Thomas, J.).
---------------------------------------------------------------------------

Soon thereafter, both courts weighed in on the extension of the GHG
regulatory program to power plants under CAA section 111. The Supreme
Court stayed the 2015 Clean Power Plan pending review by the D.C.
Circuit, which had denied a stay.\60\ The D.C. Circuit subsequently
reviewed a later rulemaking that repealed the Clean Power Plan and
replaced it in part.\61\ In American Lung Association v. EPA, 985 F.3d
914 (D.C. Cir. 2021), a divided panel reinstated the 2015 Clean Power
Plan and vacated the 2019 ACE Rule. Among other things, the panel
majority held that the major questions doctrine has no application to
the scope of our CAA section 111 authority, id. at 959-61, and rejected
the argument that generation shifting was an impermissible use of our
regulatory authority, id. at 966-68. The panel majority also rejected
challenges to the endangerment and significant contribution bases for
regulating GHGs under CAA section 111, citing Coalition for Responsible
Regulation and stating that if ``greenhouse gas emissions by fossil-
fuel-fired power plants'' do not ``significantly contribute'' to global
climate change, it would be ``nigh impossible for any source of
greenhouse gas pollution to cross that statutory threshold.'' Id. at
977.\62\
---------------------------------------------------------------------------

\60\ West Virginia v. EPA, 136 S Ct. 1000 (2016).
\61\ ``Affordable Clean Energy Rule,'' 84 FR 32520 (July 8,
2019) (``2019 ACE Rule'').
\62\ In a partial dissent, Judge Walker argued that the 2015
Clean Power Plan (and aspects retained in the 2019 ACE Rule)
violated the major questions doctrine because CAA section 111 does
not include a clear statement of authority to regulate GHG emissions
from power plants. Am. Lung Ass'n, 985 F.3d at 995-1003 (pointing to
failed legislation in 2009 that would have provided the requisite
authority to regulate GHG emissions from power plants).

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

[[Page 7701]]

In West Virginia, the Supreme Court reversed the D.C. Circuit's
treatment of the major questions doctrine and held that the 2015 Clean
Power Plan exceeded our authority to regulate existing sources under
CAA section 111(d). The Court surveyed UARG, Brown & Williamson, and
additional precedents to confirm that an agency must have more than ``a
colorable textual basis'' to assert `` `unheralded' regulatory power
over `a significant portion of the American economy.' '' 597 U.S. at
721-23 (quoting UARG, 573 U.S. at 324). In such cases, ``both
separation of power principles and a practical understanding of
legislative intent'' require the agency to ``point to `clear
congressional authorization' for the power it claims.'' Id. at 723
(quoting UARG, 573 U.S. at 324). The Court held that our reliance on
CAA section 111(d) to regulate GHG emissions was ``a major questions
case'' because we had asserted the power ``to substantially restructure
the American energy market.'' Id. at 724. That provision ``had rarely
been used in the preceding decades,'' and we had used it in an
``unprecedented'' manner ``to adopt a regulatory program that Congress
had conspicuously and repeatedly declined to enact itself.'' Id. at
724-28. Since we lacked express authorization, the Court concluded that
we lacked statutory authority for the 2015 Clean Power Plan. Id. at
732-35.\63\
---------------------------------------------------------------------------

\63\ In dissent, Justice Kagan argued that the Court had
obstructed the EPA's efforts to regulate GHG emissions: ``Today, the
Court strips the [EPA] of the power Congress gave it to respond to
`the most pressing environmental challenge of our time.'' West
Virginia, 597 U.S. at 753 (Kagan, J., joined by Breyer and
Sotomayor, J.J., dissenting) (quoting Massachusetts, 549 U.S. at
505); see also id. at 755 (``This Court has obstructed EPA's effort
from the beginning.'').
---------------------------------------------------------------------------

Following the Endangerment Finding, the EPA also received multiple
petitions for reconsideration from industry groups, States, and various
organizations arguing that our approach in 2009 was legally and
scientifically flawed and that external assessments by the IPCC, among
others, had not adequately addressed recent criticisms of climate
change science. The EPA denied these consolidated petitions in 2010
without notice and comment (``2010 Denials''). Reiterating the
scientific assertions from the technical support document (TSD) used in
2009, we emphasized that we had conducted an independent review of
outside assessments in issuing the Endangerment Finding and asserted
that the core conclusions of the Endangerment Finding remained valid
notwithstanding the flaws raised by the petitioners. The EPA also
issued a volume of response documents defending the methodologies and
experts relied upon and concluded that no new information warranted
reconsideration. 75 FR 49556.\64\
---------------------------------------------------------------------------

\64\ The D.C. Circuit rejected several petitions for review of
the 2010 Denials as part of the Coalition for Responsible Regulation
decision. 684 F.3d at 124-26.
---------------------------------------------------------------------------

In April 2022, the EPA denied, again without notice and comment, a
new round of petitions for reconsideration and rulemaking asserting
that the Endangerment Finding was legally and scientifically flawed and
undermined by more recent scientific assessments (``2022 Denials''). We
acknowledged that several recent studies contradicted assessments by
the USGCRP and IPCC but reaffirmed our earlier position that such
assessment reports are entitled to greater weight than dissenting
views.\65\ We also considered criticisms of the EPA's SCC methodology
out of scope because ``the social cost of carbon played no role in the
2009 Endangerment Finding.'' \66\ We further acknowledged that severing
the endangerment and cause or contribute analysis from the development
of subsequent regulations had impacted the EPA's approach to GHG
emission standards, including because the SAB did not have the
opportunity to review the Endangerment Finding as would otherwise have
been required by the CAA.\67\ Nevertheless, we reaffirmed our position
that CAA section 202(a) grants ``procedural discretion'' to issue
findings and emission standards separately and ``decline[d] to exercise
that discretion'' differently.\68\
---------------------------------------------------------------------------

\65\ 2022 Denials at 15-17.
\66\ Id. at 30.
\67\ Id. at 36 (noting that 42 U.S.C. 4365(c)(1) requires SAB
consultation for a ``standard'' promulgated under CAA section 202(a)
but asserting that requirement does not extend to ``findings''
issued under the same provision).
\68\ Id. at 39.
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E. Reconsideration of the 2009 Endangerment Finding

Since the EPA published the 2009 Endangerment Finding, there have
been developments in innovation, science, economics, and mitigation, as
well as significant Supreme Court decisions that provide new guidance
on how Federal agencies should interpret the statutory provisions that
Congress has tasked them with administering.\69\ Accordingly, the
Administrator determined that the Endangerment Finding should be
reconsidered to address legal and scientific developments that present
reason to question the ongoing validity and reliability of its
conclusions and to subject these important issues to public comment for
the first time since 2009.
---------------------------------------------------------------------------

\69\ See Feb. 19, 2025 Memo at 1.
---------------------------------------------------------------------------

In initiating reconsideration, the Administrator explored all
findings, support, questions, and ambiguities contained within the
science relied upon by the Endangerment Finding. On July 29, 2025, the
Administrator signed a proposed rule setting out the results of the
EPA's reconsideration to date and proposing to rescind the Endangerment
Finding and all GHG emission standards for LD, MD, and HD motor
vehicles and engines promulgated since 2009 under CAA section
202(a)(1). At proposal, we noted that the Endangerment Finding itself
and subsequent reports, studies, and analyses had acknowledged
significant questions and ambiguities presented by the observable
realities of the past nearly two decades and the recent findings of the
scientific community. We also noted that there may be as-yet-
unidentified issues or discrepancies present in the underlying
technical analysis and scientific justifications offered in the
Endangerment Finding. Finally, we noted that when confronted with
science offering a diverse array of conclusions, methodologies, and
explanations, the Administrator strove to inform his judgment to the
most impartial extent possible.
In reviewing the public response to the proposal, the Administrator
appreciated the wide variety of perspectives and significant interest
in the issues raised for further consideration. In particular, the
Administrator carefully examined the additional data, modeling, and
information submitted in connection with our request for comment on the
impact of the EPA's GHG emission standards for new motor vehicles and
engines to date and the efficacy of such regulations in addressing the
risks identified in the Endangerment Finding. The EPA has conducted
further analysis to evaluate the competing perspectives on the ability
of GHG emission standards to have a material (i.e., non-de minimis)
impact on global climate change concerns, with a particular focus on
trends in GMST and GSLR--key metrics commonly derived from climate
models and primary drivers of the Agency's causal analysis of
endangerment in the 2009 Endangerment Finding.
As discussed in section IV of this preamble, the EPA concludes that
it lacks statutory authority to resolve these questions through
regulatory findings and emission standards under CAA section 202(a)(1).
That conclusion led the Administrator to rest this final action on the
legal bases proposed as the

[[Page 7702]]

primary rationale for rescission of the Endangerment Finding and repeal
of associated GHG emission standards, as explained in sections V.A and
V.B of this preamble. As a separate but complementary basis for
rescission and repeal, the Administrator finds that the available
evidence indicates GHG emission standards under CAA section 202(a)(1)
do not impact trends in GMST or GSLR in any material way, let alone the
health and welfare impacts attributed to such trends in the
Endangerment Finding. As discussed in section V.C of this preamble,
this conclusion further indicates that the best reading of CAA section
202(a)(1) does not encompass the regulation of ``air pollution'' in the
form of global climate change concerns and serves as an independent
basis for repealing the GHG emission standards. For discussion of
public comments received on the alternative climate science basis and
the Administrator's decision not to finalize on that ground in favor of
future opportunities for fact finding and public engagement, see
section VI of this preamble.

IV. Legal Framework for Action

A. Rescission of the Endangerment Finding

The statutory authority for this final action is the same as that
relied upon in the prior actions at issue: CAA section 202(a)(1), which
requires the Administrator to ``prescribe'' and ``from time to time
revise . . . standards'' for certain air pollutants emitted by new
motor vehicles and new motor vehicle engines ``in accordance with the
provisions of this section.'' \70\ In addition, unless provided
otherwise by statute, an agency may revise or rescind prior actions so
long as it acknowledges the change in position, provides a reasonable
explanation for the new position, and considers legitimate reliance
interests in the prior position.\71\
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\70\ 42 U.S.C. 7521(a)(1).
\71\ See FDA v. Wages & White Lion Invs., L.L.C., 604 U.S. 542,
568-70 (2025); FCC v. Fox Television Stations, Inc., 556 U.S. 502
(2009); Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co.,
463 U.S. 29 (1983).
---------------------------------------------------------------------------

Nothing in the language of the relevant statutory provision
prohibits or conditions our general authority to rescind prior actions
through rulemaking. CAA section 202(a)(1) grants the Administrator
discretion to ``revise'' standards prescribed ``in accordance with the
provisions of this section'' and does not require retaining the same
level of stringency when revising or rescinding existing standards.
Moreover, the statute neither authorizes the Administrator to issue
standalone findings that trigger a duty to regulate nor prohibits the
Administrator from rescinding such findings. Rather, CAA section
202(a)(1) requires the Administrator to prescribe standards for
emissions of any air pollutant by classes of new motor vehicles or
engines when, in his judgment, emissions of such air pollutant by such
classes of new motor vehicles or engines ``cause, or contribute to, air
pollution which may reasonably be anticipated to endanger public health
or welfare.'' Notably, the EPA has consistently assumed that it has the
statutory authority to rescind the Endangerment Finding in reviewing
the merits of petitions for reconsideration since 2009 and did not
state that we lack such reconsideration authority.\72\
---------------------------------------------------------------------------

\72\ See, e.g., 2022 Denials at 7-10 (denying mandatory
reconsideration under CAA section 307(d) and reviewing the petitions
on the merits as rulemaking petitions under APA section 553(e)); 75
FR 49556, 49560-63 (Aug. 13, 2010) (denying mandatory
reconsideration under CAA section 307(d) without asserting that the
EPA lacked statutory authority to rescind or revise the Endangerment
Finding).
---------------------------------------------------------------------------

The EPA acknowledges that rescinding the Endangerment Finding
involves significant changes to the legal interpretations adopted in
the Endangerment Finding and retained in subsequent actions. For
example, the interpretation of CAA section 202(a) that we are
finalizing precludes the EPA from issuing standalone endangerment and
contribution findings and instead requires the Agency to make findings
for particular air pollutant emissions and classes of new motor
vehicles and engines as an integral step in a rulemaking to prescribe
standards for such emissions and classes, consistent with our decades-
long practice prior to 2009 in regulating non-GHG air pollutants.
Furthermore, the interpretation of CAA section 202(a)(1) that we are
finalizing in this action reverses the basis for the Endangerment
Finding by concluding that global climate change concerns cannot
satisfy the statutory standard for regulation under CAA section
202(a)(1). This interpretation is the best reading of the statute, and
it is different from the final actions taken by the Agency since 2009
with respect to GHG emission standards under CAA section 202(a).\73\
For example, we acknowledge that the EPA changed its position in 2009
and argued in actions finalized since that time and in briefs filed in
defense of those actions that CAA section 202(a) authorizes us to
regulate in response to global climate change concerns.\74\ We also
acknowledge that the EPA argued in actions finalized since 2009 and in
briefs filed in defense of those actions that the major questions
doctrine has no application to CAA section 202(a)(1).\75\ However,
intervening legal developments must be considered when evaluating these
statements as they developed over time. We initially developed those
novel positions without the benefit of the Supreme Court's decisions in
UARG, Michigan, and West Virginia, which explained and applied the
major questions doctrine to related GHG emission regulations. Moreover,
we note that each of these major actions and rules predated the Supreme
Court's decision in Loper Bright, which overruled Chevron deference to
agency statutory interpretation and clarified that statutes have a
single, best meaning.\76\ In light of these decisions and upon further
review of the EPA's prior statements on the applicability and impact of
the major questions doctrine, we are finalizing, as proposed, a new
position that more faithfully adheres to precedent and governing legal
principles. For discussion of CAA section 202(a)(1) and related
statutory provisions interpreted in this final action, see section V of
this preamble.
---------------------------------------------------------------------------

\73\ See, e.g., 74 FR 66496 (Dec. 15, 2009); 75 FR 25324 (May 7,
2010); 76 FR 57106 (Sept. 15, 2011); 77 FR 62624 (Oct. 15, 2012); 81
FR 73478 (Oct. 25, 2016); 85 FR 24174 (Apr. 30, 2020); 86 FR 74434
(Dec. 30, 2021); 89 FR 27842 (Apr. 18, 2024); 89 FR 29440 (Apr. 22,
2024).
\74\ See, e.g., 74 FR 66496, 66524 (Dec. 15, 2009) (Endangerment
Finding); 2022 Denials at 1; 75 FR 49556 (Aug. 13, 2010) (2010
Denials).
\75\ See, e.g., 89 FR 29440, 29468-70 (Apr. 22, 2024) (2024 HD
GHG Emission Standards Rule) (arguing that regulation of GHG
emissions under CAA section 202(a) in response to global climate
change concerns is not a question of significant importance, that
the EPA has clear congressional authorization, and that use of this
authority since 2009 is not novel); 89 FR 27842, 27897 (Apr. 18,
2024) (2024 LD and MD Multi-Pollutant Emission Standards Rule)
(same). In these final rules, the EPA also took the position--
repudiated in this final action--that it is permissible to expect
manufacturers to comply with GHG emission standards by shifting to
EVs.
\76\ 603 U.S. at 412-13 (overruling Chevron U.S.A., Inc. v.
NRDC, Inc., 467 U.S. 837 (1984)).
---------------------------------------------------------------------------

The EPA is also finalizing that GHG emission standards for new
motor vehicles and engines are futile because they have no material
(i.e., non-de minimis) impact on the global climate change concerns
animating this regulatory program and is reaching two separate and
independent conclusions as a result. First, we conclude that futility
lends further support to the understanding that CAA section 202(a)(1)
is best read to encompass ``air pollution'' that endangers human health
and the environment through local and regional exposure and that
domestic regulation can impact without requiring

[[Page 7703]]

international emissions reductions. Second, we conclude that futility
warrants repeal of the GHG emission standards independent from the
Endangerment Finding because they impose immense burdens without
furthering any statutory objective. These additional bases for this
final action represent a change from the novel position taken in
actions and rulemakings since 2009 to prescribe and revise GHG emission
standards under CAA section 202(a)(1).\77\ For example, we asserted in
the Endangerment Finding that the ability of GHG emission standards to
impact global climate change concerns was outside the scope of the CAA
section 202(a)(1) endangerment and contribution analysis, 74 FR 66501-
02, that we could not consider the degree of emissions reductions that
could be achieved by regulations issued as a result of the findings, 74
FR 66507-08, and that the ``unique'' nature of global climate change
concerns justified accepting a different analysis than that
traditionally applied to mobile-source air pollution problems, 74 FR
66538, 66543. In GHG emission standard rulemakings since 2009, we
analyzed the impact of potential standards in terms of contribution,
i.e., tons of emissions, rather than impact on endangerment, i.e., from
trends in GMST and GSLR that lead in turn to the health and welfare
impacts predicted in the Endangerment Finding. That is, we generally
evaluated potential GHG emissions reductions (in tons of CO<INF>2</INF>
equivalent) \78\ and used SCC methodologies to attach a dollar value to
such emissions reductions.\79\ See section V.C of this preamble for
further discussion of these additional rationales and the EPA's prior
positions.
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\77\ See, e.g., 74 FR 66496, 66524 (Dec. 15, 2009); 75 FR 25324
(May 7, 2010); 76 FR 57106 (Sept. 15, 2011); 77 FR 62624 (Oct. 15,
2012); 81 FR 73478 (Oct. 25, 2016); 85 FR 24174 (Apr. 30, 2020); 86
FR 74434 (Dec. 30, 2021); 89 FR 27842 (Apr. 18, 2024); 89 FR 29440
(Apr. 22, 2024).
\78\ See, e.g., 75 FR 25324 (May 7, 2010).
\79\ See, e.g., 89 FR 29440, 29675 (Apr. 22, 2024) (2024 HD GHG
Emission Standards Rule) (``While the EPA did not conduct modeling
to specifically quantify changes in climate impacts resulting from
this rule in terms of avoided temperature change or sea-level rise,
the Agency did quantify climate benefits by monetizing the emission
reductions through the application of estimates of the social cost
of greenhouse gases (SC-GHGs).''); 89 FR 27842, 28099 (Apr. 18,
2024) (2024 LD and MD Multi-Pollutant Emission Standards Rule)
(same).
---------------------------------------------------------------------------

The EPA further acknowledges that repealing the GHG emission
standards based on the proposed rescission of the Endangerment Finding
is a departure from our position in rulemakings since 2009 that
prescribed and revised GHG emission standards for LD, MD, and HD
vehicles and engines under CAA section 202(a)(1). This rescission
eliminates the statutory basis for those standards because we relied on
the Endangerment Finding in each rulemaking to invoke our authority
under CAA section 202(a)(1) without making the required findings for
GHGs emitted by the class or classes of new motor vehicles or engines
at issue in each rulemaking. To the extent we reaffirmed the
Endangerment Finding in subsequent standard rulemakings, the
conclusions we are finalizing in this action eliminate the improperly
claimed statutory basis for such reaffirmations, all of which relied on
the same underlying interpretation of CAA section 202(a)(1) as
encompassing the regulation of GHG emissions based on global climate
change concerns. See section VII of this preamble for further
discussion of each prior rulemaking and the regulatory changes we are
making to repeal all GHG emission standards currently in effect for new
motor vehicles and engines on bases finalized in this action.
As discussed throughout this preamble, the EPA is finalizing these
changes to comply with limits on our statutory authority under the best
reading of CAA section 202(a)(1), adhere to the legal limits on our
power to set national policy within our constitutional system of
democratic government, and realign Agency resources to prioritize core
statutory responsibilities that protect human health and the
environment. Importantly, the Nation's policy response to global
climate change concerns was a major issue in the 2024 presidential
election, in which voters were presented with distinct legal and policy
approaches and elected a candidate promising a change in policy. Under
these circumstances, the election of a new Administration is an
independent and sufficient basis for reassessing and revising legal
interpretations to faithfully adhere to the best reading of the
statute.\80\ Democratic accountability is essential to the exercise of
delegated authority by administrative agencies,\81\ and retaining the
Endangerment Finding and associated GHG emission standards without
clear statutory authority would frustrate, not promote, constitutional
values and the rule of law. The EPA lacks authority to retain the
Endangerment Finding under the best reading of CAA section 202(a)(1),
and the statute controls regardless of policy preferences.\82\
---------------------------------------------------------------------------

\80\ See State Farm, 463 U.S. at 59 (Rehnquist, J., concurring
in part and dissenting in part); PETA v. USDA, 918 F.3d 151, 158
(D.C. Cir. 2019) (``new administrations are entitled to reevaluate
and modify agency practices, even longstanding ones''); Nat'l Ass'n
of Home Builders v. EPA, 682 F.3d 1032, 1043 (D.C. Cir. 2012) (``the
inauguration of a new President and the confirmation of a new EPA
Administrator'' went ``a long way toward explaining why EPA''
changed policy).
\81\ See, e.g., U.S. Telecom Ass'n v. FCC, 855 F.3d 381 (D.C.
Cir. 2017) (Brown, J., dissenting from denial of rehearing en banc);
Elena Kagan, Presidential Administration, 114 Harv. L. Rev. 2245,
2252-53, 2332-34 (2001).
\82\ Loper Bright, 603 U.S. at 403; West Virginia, 597 U.S. at
735; UARG, 573 U.S. at 325.
---------------------------------------------------------------------------

1. Issues Raised Regarding Rescission Authority
The EPA received substantial comments on the proposed bases for
rescinding the Endangerment Finding but relatively few specifically
addressing the separate question whether we have the authority to
rescind, provided that the rescission is supported by adequate grounds.
Most comments received on that issue agreed that the EPA may reconsider
prior actions unless the relevant statute provides otherwise and
further agreed that nothing in CAA section 202(a)(1) conditions or
limits our ability to reconsider prior actions. We appreciate these
comments and, as noted above, are finalizing this action based on the
statutory authority conferred in CAA section 202(a)(1) and the
background principle that agencies may reconsider, revise, and rescind
prior actions unless provided otherwise by the relevant statute.
Several commenters raised contrary arguments that did not change our
view from proposal. For more detailed comment summaries and responses,
see the Response to Comments document.
Comment: A few adverse commenters argued that rescinding the
Endangerment Finding would not support repealing the associated GHG
emission standards because the standards-setting rulemakings reaffirmed
and reinforced the Endangerment Finding with additional evidence. Some
of these commenters also argued that CAA section 202(a)(1) is a
precautionary provision, which, they asserted, means that we cannot
rescind the Endangerment Finding based on a lack of confidence in the
assumptions made and conclusions stated in that action.
Response: The EPA disagrees that rescinding the Endangerment
Finding would not impact subsequently issued GHG emission standards and
notes that these commenters misunderstand the impact of our proposal
that CAA section 202(a)(1) does not authorize regulating GHG emissions
in response to global climate change concerns. The Agency has
consistently maintained that, at

[[Page 7704]]

minimum, a finding that the relevant air pollutant emissions cause or
contribute to air pollution that endangers public health or welfare is
a prerequisite to prescribing emission standards. In the Endangerment
Finding, we asserted that the statute's ``lack of specific direction''
with respect to the timing of findings and of associated regulations
granted ``procedural discretion'' to issue the actions separately. 74
FR 66501. But we maintained that the findings created the predicate
authority and obligation to issue associated emission standards and
acknowledged that it was at least permissible to issue the findings and
standards in a single action. 74 FR 66501-02.
Finalizing the rescission of the Endangerment Finding for lack of
authority under CAA section 202(a)(1) necessarily means that we lack
statutory authority to prescribe or maintain GHG emission standards for
new motor vehicles and engines. Whether we cited to additional evidence
``reinforcing'' the Endangerment Finding in subsequent rulemakings--and
whether that additional evidence would itself have been sufficient to
satisfy CAA section 202(a)(1) absent the Endangerment Finding--is
irrelevant, as each of these actions rested on the novel statutory
interpretation adopted for the first time in the Endangerment Finding.
The best reading of the statute identified and applied in this final
action necessarily overrides the contrary interpretation relied upon in
these prior actions and therefore eliminates the legal basis for those
prior actions. See section V.A and V.B of this preamble for further
discussion of CAA section 202 and the legal position taken by the EPA
in actions since 2009. With respect to commenters' precautionary
arguments, the EPA is not finalizing the proposed alternative basis for
rescission and repeal based on a new climate science finding by the
Administrator. See section VI of this preamble for further discussion
of the bases we are not finalizing at this time.
Comment: Some commenters argued that the CAA limits our authority
to rescind prior actions, quoting NRDC v. Regan, 67 F.4th 397, 401
(D.C. Cir. 2023), for the proposition that the EPA ``has no inherent
authority'' to reconsider its decisions. These commenters asserted that
CAA section 202(a)(1) is best read as limiting our rescission authority
to reconsideration under CAA section 307 or extraordinary
circumstances, such as mistake or fraud, and that Congress authorized
us only to update emission standards based on developments in science,
technology, and economics by providing that we must ``from time to time
revise'' emission standards ``in accordance with the provisions of this
section.'' According to these commenters, rescinding the Endangerment
Finding and associated regulations exceeds that authority.
Response: The EPA disagrees with these comments, which misconstrue
the statute and misapply relevant case law. The D.C. Circuit's divided
opinion in NRDC addressed our withdrawal of a regulatory determination
for a drinking water contaminant under the Safe Drinking Water Act
(SDWA) in lieu of issuing a national primary drinking water regulation.
The panel majority and separate opinion agreed that ``the power to
decide is normally accompanied by the power to reconsider'' unless
Congress has `` `limit[ed] [the] agency's discretion to reverse
itself.' '' 67 F.4th at 401 (quoting New Jersey v. EPA, 517 F.3d 574,
582-83 (D.C. Cir. 2008)). Interpreting the statutory language at issue,
the panel majority concluded that SDWA section 1412 imposed such a
limitation by mandating a sequential, two-step process under which the
EPA ``shall'' propose a regulation within 24 months ``[f]or each
contaminant that the Administrator determines to regulate'' in a final
regulatory determination. Id. (quoting 42 U.S.C. 300g-1(b)(1)(A),
(b)(1)(E)); but see id. at 408 (Pan, J., concurring in the judgment)
(arguing that ``nothing in the [SDWA] forbids the EPA from withdrawing
a determination to regulate'' because the ``statute is silent on that
issue''). NRDC did not challenge the established background principle
that agencies may reconsider prior actions taken under a statutory
authority absent statutory indicia to the contrary, and the language of
CAA section 202(a)(1) is different in virtually every respect from the
content, sequence, and timing requirements in SDWA section 1412.
CAA section 202(a)(1) sets out authority to regulate under certain
conditions and provides that such regulations should be revised over
time. The statutory language ``from time to time revise'' refers to the
emission standards promulgated when the Administrator exercises
``judgment'' to determine that an air pollutant emitted from new motor
vehicles or engines causes or contributes to air pollution which may
reasonably be anticipated to endanger public health or welfare. Beyond
reference to the Administrator's ``judgment,'' the statute contains no
language constraining or limiting the power to reconsider a finding.
Nor does CAA section 202(a)(1) require the EPA to establish regulations
by a certain date or for certain pollutants, unlike many other
provisions in CAA section 202 and throughout the CAA.\83\ Had Congress
intended to restrict the repeal of CAA section 202(a)(1) emission
standards based on the Administrator's findings of endangerment and
contribution, it knew how to do so,as evidenced by provisions elsewhere
in the statute imposing such restrictions.\84\ Additional statutory
language providing that emission standards must be revised ``in
accordance with the provisions of this section'' merely clarifies that
revised standards are subject to the same conditions as the original
standards (i.e., an applicable endangerment finding and the various
substantive requirements for standards set out in CAA section
202(a)(2), (a)(3), et seq.). Finally, we note that this understanding
of our reconsideration authority is rooted in consistent practice; as
noted above, we assumed that we had such authority when denying
reconsideration petitions on the merits in 2010 and 2022.
---------------------------------------------------------------------------

\83\ Compare 42 U.S.C. 7409 (mandating NAAQS for criteria
pollutants by a date certain), 7412 (mandating regulation of
hazardous air pollutants from listed source categories by a date
certain), 7429 (same for waste combustors), 7521(a)(3)(B)(ii)
(mandating minimum emission standards for HD vehicles for certain
pollutants by a date certain), 7521(a)(6) (mandating certain control
devices for LD vehicles after a date certain), 7521(b), (g)-(l)
(mandating various emission standards for enumerated pollutants by
dates certain).
\84\ Notably, Congress provided in CAA section 202(b)(1)(C) that
the EPA cannot relax the pollutant-specific emission standards
required ``under [CAA section 202(b)]'' when revising such standards
``under [section 202(a)(1)].'' 42 U.S.C. 7521(b)(1)(C). That
limitation on revision authority does not apply to emission
standards promulgated solely under CAA section 202(a) as an exercise
of the Administrator's judgment. Comparable provisions appear
elsewhere in the statute as well. See, e.g., 42 U.S.C. 7502(e)
(providing that if the EPA ``relaxes'' a NAAQS, it must within 12
months require ``controls which are not less stringent than the
controls applicable to areas designated nonattainment before such
relaxation'').
---------------------------------------------------------------------------

With respect to CAA section 307 and commenters' asserted mistake or
fraud limitation, the EPA assumes commenters meant to suggest that we
may only reconsider prior actions through mandatory reconsideration
under CAA section 307(d) or by meeting common law standards originally
developed for voiding a contract. We are not aware of any precedent
establishing a mistake or fraud limitation and cannot agree that there
is a plausible basis for doing so given the well-established principle
that agencies may reconsider prior actions unless Congress provides
otherwise. As to CAA section 307, this rulemaking followed the
applicable procedural requirements set out in that provision. The
mandatory reconsideration procedure in CAA

[[Page 7705]]

section 307(d)(7)(B) applies when a petitioner was unable to raise a
centrally relevant objection during a public comment period, not to an
EPA-initiated reconsideration.
Comment: A few commenters raised retroactivity concerns with the
rescission and repeals, arguing that Congress must expressly authorize
rules with retroactive effect and that repealing GHG emission standards
for MY 2026 and earlier vehicles would be impermissibly retroactive.
Some of these commenters cited Bowen v. Georgetown University Hospital,
488 U.S. 204 (1988), as setting out a clear statement rule for
authority to issue retroactive rules.
Response: The EPA disagrees that repealing GHG emission standards
for MY 2026 and earlier vehicles would have retroactive effect, as
nothing in this final action ``attaches new legal consequences to
events completed before its enactment.'' Landgraf v. USI Film Prods.,
511 U.S. 244, 270 (1994). As a practical matter, manufacturers have
already completed virtually all of the activities necessary to comply
with the GHG emission standards for prior MY vehicles. Motor vehicles
and engines have been designed and sold with compliant control
mechanisms, the proverbial eggs are, in that sense, already scrambled.
Repealing the GHG emission standards for prior MYs relieves only a
limited set of compliance obligations, including certain ongoing
reporting requirements, and does not impose any new or additional
obligations on regulated parties.\85\ We conclude that repeal of the
GHG emission standards for prior MYs is necessary notwithstanding the
limited practical effect to ensure that our regulations are squarely
grounded in statutory authority and avoid the inconsistency that would
be created by retaining these regulations while repealing standards for
future MY vehicles and engines. For further explanation of the impacts
of the rescission and repeals, see section VII of this preamble and the
Response to Comments document. For discussion of the distinct subject
of reliance interests, see section IV.A.2 of this preamble.
---------------------------------------------------------------------------

\85\ For example, any contractual provisions between the seller
(e.g., dealership) and a vehicle purchaser would not be changed or
disrupted solely by operation of this final action.
---------------------------------------------------------------------------

2. Issues Raised Regarding Reliance Interests
To better assess potential reliance interests, the EPA sought
comment on whether regulated parties or other stakeholders have relied
in a significant and legally cognizable manner on our assertion of
authority to regulate GHG emissions from new motor vehicles and engines
and the requirements imposed pursuant to that asserted authority. We
noted that such reliance may be relevant considerations to be weighed
against competing rationales when deciding whether to change the
Agency's position under relevant case law, including DHS v. Regents of
University of California, 591 U.S. 1 (2020). Specifically, we sought
comment on potential reliance interests by regulated parties that have
expended resources complying with existing standards, including by
pricing compliance into costs for consumers, and on potential reliance
interests by other stakeholders on the Endangerment Finding and GHG
emission standards.
With respect to regulated parties, we noted that because many
compliance costs are incurred as part of research and development and
during manufacturing, with the exception of the need to purchase
compliance credits, this final action would have small to no impacts on
MYs 2012-2024, limited impacts for MYs 2024-2026, and entirely relieve
future regulatory obligations for MY 2027 and beyond. We also noted
that the rescission and repeals would not mandate any particular
response by regulated parties and would instead provide additional
flexibility by relieving obligations. For discussion of regulatory
tools available to address transitional compliance concerns, see
sections III.A, VI.B, and VI.C of the preamble to the proposed rule. We
also noted that regulated parties may have an interest in national
uniformity and preemption and discussed the continued applicability of
CAA section 209(a) and other sources of Federal preemption in sections
III.A and VI.A of the preamble to the proposed rule.
With respect to other potential interests held by regulated parties
and additional stakeholders, we noted that the rescission and repeals
would have no impact on existing regulatory provisions for criteria
pollutant and air toxics emission standards or for the separate economy
and fuel-efficiency standards administered by NHTSA. We explained that
general interests in regulating GHG emissions based on global climate
change concerns would not justify retaining the GHG regulatory program
for new motor vehicles and engines in the absence of statutory
authority, and that potential dangers from exposure to the six gases
combined in the Endangerment Finding would continue to be regulated
when appropriate under other, more specific grants of statutory
authority. For further discussion, see sections III.A and IV.A.2 of the
preamble to the proposed rule. Finally, we recognized that the EPA has
since relied on the Endangerment Finding as authority for GHG
regulatory actions under other provisions of the CAA, including several
vacated by the Supreme Court,\86\ and noted that we would address those
actions as appropriate in separate rulemaking proceedings.
---------------------------------------------------------------------------

\86\ See West Virginia, 597 U.S. 697; UARG, 573 U.S. 302.
---------------------------------------------------------------------------

The EPA received significant comments on reliance interests from a
variety of regulated parties and interested stakeholders that reflected
diverging views on whether we should consider reliance interests, what
reliance interests we should consider, and how such interests should be
addressed in this rulemaking. We agree with commenters' suggestion that
under Loper Bright, it is unclear how reliance interests could justify
retaining or prolonging a regulatory action that is inconsistent with
the best reading of the statute. Nevertheless, we carefully reviewed
public comments to assess whether any aspects of this final action
should be adjusted to account for reliance interests where possible to
do so consistent with our statutory authority. Ultimately, we are
finalizing the primary legal basis for the rescission and repeals as
proposed along with the additional futility conclusions discussed
above. Reliance interests raised by adverse commenters did not change
our proposed view that a lack of statutory authority necessitates
rescinding the Endangerment Finding and repealing the GHG emission
standards and deprives us of discretion to issue revised regulations
establishing a phase-out or wind-down approach. For more detailed
comment summaries and responses, see the Response to Comments document.
Comment: Commenters argued that reliance interests are irrelevant
when an agency proposes to rescind a prior action that exceeded its
statutory authority. These commenters argued that because the EPA
lacked statutory authority to issue the Endangerment Finding and
associated GHG regulations, no amount of reliance could justify
continuing a program that wields a power neither Congress nor the
Constitution granted to the Agency. At least one commenter also cited
Justice Thomas's dissenting opinion in Regents, which argued that
reliance interests are irrelevant when an agency rescinds an unlawful
prior action. 591 U.S. at 60.
Response: The EPA appreciates these comments and agrees that
reliance

[[Page 7706]]

interests alone could not justify retaining or extending a regulation
that exceeds our statutory authority. Particularly after Loper Bright,
the relevance of reliance interests under such circumstances is
unclear.\87\ On one hand, courts have consistently held that agencies
must consider significant reliance interests when exercising their
authority to change positions. On the other, these cases typically
addressed reliance interests in contexts where the agency faced a
choice between competing policy options. Under Chevron, that included
the choice between permissible interpretations of the relevant statute.
Now that Chevron has been overruled, however, the range of agency
discretion is considerably narrowed because the best reading of the
statute controls. Loper Bright, 603 U.S. at 401-04. When the statute is
best read as conferring discretion, courts use ordinary tools of
interpretation to ``fix the boundaries of the delegated authority'' and
ensure the agency reasonably exercises its discretion within those
boundaries. Id. at 395.\88\
---------------------------------------------------------------------------

\87\ Since Loper Bright, the Supreme Court has returned to the
reliance interest prong of the change-in-position doctrine only in a
case involving arbitrary and capricious claims that did not turn on
questions of statutory interpretation. See Wages & White Lion, 604
U.S. at 567.
\88\ In Loper Bright, the Supreme Court also stated that
Chevron's overruling is not a sufficient reason to invalidate
``specific agency actions'' upheld under the Chevron framework. 603
U.S. at 412. That stare decisis limitation does not apply to the
rescission and repeals in this final action, which is a separate and
subsequent decision in which the EPA is changing its interpretation
of CAA section 202(a)(1) and repudiating our prior actions as
exceeding our statutory authority. See, e.g., Ohio Telecom Ass'n v.
FCC, 124 F.4th 993, 1002 (6th Cir. 2025) (courts are not bound by
prior holdings applying the Chevron framework in the same statutory
context when the agency action on review ``is not the `specific
agency action' '' upheld in the prior decision).
---------------------------------------------------------------------------

Relevant precedents decided before Loper Bright do not resolve the
question whether the illegality of a prior agency action is a
sufficient explanation for rescission under the change-in-position
doctrine. In Encino Motorcars, LLC v. Navarro, 579 U.S. 211 (2016), for
example, the Supreme Court applied the Chevron framework to an agency's
decision to alter a longstanding statutory interpretation that applied
an exemption to a class of employees. The Court found the change
arbitrary and capricious because the agency failed to consider
industry's legitimate reliance on the applicability of the exemption.
Id. at 221-22. The decision appeared to assume for purposes of deciding
the case that either interpretation could be permissible under Chevron
and did not address whether, had the prior interpretation been
unlawful, that determination would have been a sufficient explanation
for the new interpretation.
In Regents, the Court found the rescission of a deferred action
memorandum arbitrary and capricious for failing to consider legitimate
reliance interests, even where the memorandum had provided that the
deferred action program ``conferred no substantive rights.'' 591 U.S.
at 30. That holding was informed by the Court's decision not to address
whether the agency lacked statutory authority to issue the original
memorandum. Compare id. at 25-28, 32, with id. at 40, 60 (Thomas, J.,
dissenting) (arguing that reliance interests were irrelevant because
the agency was rescinding an unlawful action). Rather, the Court noted
that the agency had taken the view that it retained discretion in
deciding how to wind down the program, id. at 25, and assumed on that
basis that the agency could have accommodated reliance interests given
its ``considerable flexibility in carrying out its statutory
responsibility,'' id. at 32.
The conclusion that we lack statutory authority under CAA section
202(a)(1) to regulate GHG emissions in response to global climate
change concerns leaves us without discretion to issue revised
regulations. There is no ``water under the bridge'' exception for
unlawful agency action, and the change-in-position doctrine does not
expand an agency's statutory authority for the purpose of addressing
reliance interests. The Supreme Court previously rejected our efforts
to reduce compliance burdens triggered by our GHG regulatory program in
UARG, holding that the Tailoring Rule exceeded our statutory authority
and demonstrated that the underlying Triggering Rule was itself
unlawful. 573 U.S. at 328. Here, retaining or altering the GHG emission
standards because of reliance interests would similarly require
rewriting the statute to confer ``power that neither Congress nor the
Constitution'' gave us. Regents, 591 U.S. at 60 (Thomas, J.,
dissenting). Adopting regulatory provisions to phase out or winddown
the Endangerment Finding and GHG emission standards would be
inconsistent with the conclusion that we lack statutory authority for
the program, potentially rendering both aspects of the action arbitrary
and capricious. CAA section 202(a)(1) is binary in this respect. Our
authority to delay or adjust standards under additional provisions of
CAA section 202 cannot be accessed without first passing through the
narrow gate of CAA section 202(a)(1).
Nevertheless, as discussed below and further detailed in the
Response to Comments document, we reviewed and considered reliance
interests raised by stakeholders in the interest of transparency and
public engagement. This discussion is not and should not be understood
as a concession that such consideration is legally required, or that
any disagreement with our consideration of particular reliance
interests undermines this final action.
Comment: Many commenters supportive of the proposal argued that
stakeholders could not have significant reliance interests warranting
retention of the Endangerment Finding and GHG emission standards given
the nature of the rescissions and repeals. These commenters noted that
the rescission and repeals would relieve rather than impose
obligations, and that manufacturers and others remain free to move
forward with current plans and designs.
Response: The EPA agrees that this final action relieves compliance
obligations under the CAA and does not require anything further of
regulated parties with respect to GHGs. As noted at proposal, unlike
the GHG emission standards, this final rescission and repeal action
increases flexibility and does not require manufacturers to change
plans if doing so would raise timing concerns within the MY structure
of the new motor vehicle and engine market. With respect to
informational labels and warranties, manufacturers may elect to proceed
with implementation or not, and nothing in this final action
invalidates existing labels or contracts entered into between or among
manufacturers, suppliers, and purchasers. We acknowledge that regulated
parties have already incurred compliance costs because of the GHG
emission standards and, particularly with respect to MY 2026 and beyond
vehicles, have yet to recoup such costs through sales. However, those
costs were incurred because of the GHG emission standards rather than
this final action and cannot legitimately be attributed to this final
action. Nor is it the case that this final action deprives regulated
parties of a benefit to which they would have been entitled by
complying with the GHG emission standards. The ``benefit'' of
compliance is the avoidance of enforcement actions and potential
penalties under the CAA. This final action does not subject regulated
parties to increased risk of enforcement.
The evaluation of reliance interests is a context-specific inquiry
that turns on the structure of the regulatory program and the nature of
related private

[[Page 7707]]

arrangements. Courts have recognized that asserted reliance interests
may be unreasonable in light of the statutory scheme, Am. Fuel &
Petrochemical Mfrs. v. EPA, 937 F.3d 559, 578 (D.C. Cir. 2019), and
that the duty to consider reliance interests ``exists in tandem with
the nature of the reliance interests at issue,'' Am. Petrol. Inst. v.
DOI, 81 F.4th 1048, 1060 (10th Cir. 2023). CAA section 202 recognizes
the MY structure of the vehicle market in various ways, including by
distinguishing between ``new'' and existing vehicles, and we have
prescribed emission standards on an MY basis for decades. Regulated
parties are aware that emission standards may be changed and updated
for future MYs, and, as explained above, face minimal ongoing
regulatory obligations with respect to past MYs. Cases involving
legally significant reliance interests by regulated parties have almost
always involved agency actions that increase regulatory obligations.
See, e.g., Encino Motorcars, 579 U.S. at 223. Where, as here, the
agency action relieves regulatory obligations, regulated parties are
not harmed by the additional flexibility of choosing between
maintaining their existing plans or altering them as they see fit. See,
e.g., Arizona v. EPA, 77 F.4th 1126, 1130 (D.C. Cir. 2023) (finding no
standing to challenge compliance deadline extension because the rule
``in no way prevented primacy states from proceeding on the original
schedule'').
For these reasons, we do not believe that existing compliance
investments by regulated parties are the type of significant reliance
interests that warrant special consideration in the context of this
rulemaking. Even taking them into account, however, such reliance
interests do not expand the EPA's statutory authority under CAA section
202(a)(1). As explained above, the best reading of the statute
precludes us from maintaining a GHG emission standard program for
vehicles and engines. For further discussion of the bases for this
final action, see section V of this preamble. For discussion of more
specific compliance-related concerns, including facility investments
and compliance credits, see the comment and response summaries below
and the Response to Comments document.
Comment: Some commenters asserted that regulated parties have
invested substantially in complying with the GHG emission standards,
including by operating, constructing, and announcing facilities to
manufacture EVs, and that such investments by various actors in the
supply chain since 2007 amount to $211 billion. These commenters also
asserted that American manufacturers have been at the forefront of
developing and deploying responsive technologies, many of which are
already in production and use. Several of these commenters argued that
we have not justified proceeding with the rescission and repeals given
these investments, while others suggested that we should consider a
more limited repeal of the most recent GHG emission standards rather
than a broader rescission of the Endangerment Finding.
A different set of commenters contested the relevance of such
reliance interests, arguing that many of these investments predate the
EPA's most recent GHG emission standards, that the most recent GHG
emission standards improperly bail out automakers' bad EV investments,
and that automakers are already retreating from EV production for
independent reasons.
Response: The EPA acknowledges that certain regulated parties have
invested significantly in EV production and technologies that have been
or could be used to comply with the GHG emission standards. We also
acknowledge that those companies have already reaped significant value
from this program by selling credits to other companies over the years.
As discussed above, however, nothing in this final action precludes
market participants from continuing to make such investments or removes
any benefit capable of engendering cognizable reliance interests. Nor
are such investments capable of expanding the EPA's statutory authority
under CAA section 202(a)(1).
In general, we do not believe that the investments in EVs and
related technologies raised by commenters should be attributed
exclusively to the EPA's current GHG emission standard requirements.
The new motor vehicle and engine market is complex and informed by a
wide variety of economic and regulatory considerations. As several
commenters recognized, some of these investments predate our most
recent GHG emission standards rulemakings in 2024 for MYs 2027 and
beyond, and some predate the Endangerment Finding. With respect to
economic influences, we note that EV demand has been subject to
significant fluctuation and declines unrelated to this rulemaking. The
decline in demand is attributable in part to Congress, which recently
repealed certain tax credits and subsidies for EVs and disapproved
three prior EPA preemption waivers for EV-forcing California vehicle
and engine regulations. Changes in consumer preferences are also
relevant factors. The ability of market participants to earn a return
on EV and related investments thus turns on a variety of factors that
ultimately fall outside the Agency's regulatory wheelhouse. The CAA
requires us to take cost into account in various ways, but it does not
require the EPA to ensure that EV investments turn a profit.
Comment: Several commenters asserted that automakers have relied on
the EPA's GHG emission standards to export vehicles and engines
overseas on the understanding that products meeting our standards will
generally also meet international emission standards. These commenters
argued that the rescission and repeal of U.S. GHG emission standards
will create uncertainty and raise costs for regulated parties based on
this additional export market concern.
Response: The EPA disagrees that possible challenges facing
automakers in complying with international emission standards are
legitimate reliance interests that counsel against the rescission and
repeals. We question the premise that automakers assume their products
will comply with applicable emission standards in export markets, as
GHG emission standards are not in place for new vehicles and engines
(or the same classes of new vehicles and engines) in all export markets
and vary significantly among nations where such GHG emission standards
are in place and applicable to imports. We also note that many
automakers structure design, marketing, and production strategies to
account for differing emission standards across various markets, both
for GHG emissions and for emissions of criteria pollutants and air
toxics. Regardless, as discussed above, nothing in this final action
prevents regulated parties from maintaining current plans to the extent
that they believe doing so is a convenient way to more easily
participate in export markets.
Comment: Several commenters raised concerns about the GHG
compliance credit regime that some regulated parties have used to
comply with the existing regulations. These commenters argued that
companies have accumulated credits over the past 15 years and, in some
cases, already booked those credits as assets. Several of these
commenters presented this as a reason not to finalize the rescission
and repeals, while others requested a wind-down period.
Response: The EPA has consistently maintained that regulated
parties lack a property right in compliance credits or

[[Page 7708]]

their use to demonstrate compliance.\89\ We note that the relevant
universe of compliance credits potentially impacted by this final
action is much smaller than some commenters suggest, as credits are
specific to compliance years and expire after five years.\90\ Credits
for MY 2020 and previous vehicles are expired, and potential credits
for MY 2026 and beyond vehicles are not yet in place. These
considerations lead us to conclude that the impact on stakeholders
arising from compliance credit issues will be relatively small and
temporary. Additionally, as discussed within the Response to Comments
document, the EPA has reduced the value of emission credits within
trading programs previously.
---------------------------------------------------------------------------

\89\ See 40 CFR 86.1865-12(k)(2) (``There are no property rights
associated with CO<INF>2</INF> credits generated under this subpart.
Credits are a limited authorization to emit the designated amount of
emissions. Nothing in this part or any other provision of law shall
be construed to limit EPA's authority to terminate or limit this
authorization through a rulemaking.'').
\90\ See 73 FR 25692 (May 7, 2010) and 40 CFR 86.1865-12(k)(2).
Relatedly, see 40 CFR 86.1861-17(b)(3) (LD and MD vehicle credits);
40 CFR 1036.740(d) (HD engine credits), and 1037.740(c) (HD vehicle
credits).
---------------------------------------------------------------------------

More fundamentally, our lack of statutory authority to retain the
GHG emission standards means that we lack discretion to issue revised
regulations that incorporate a phase-out or wind-down approach to
address concerns related to this compliance mechanism.
Comment: Some commenters asserted that State and local governments
have relied on the EPA's GHG regulatory program as a baseline to craft
climate policy and invested substantial resources in EV manufacture and
development, EV infrastructure, including charging stations, and
transportation electrification more generally. Several of these
commenters also asserted that States have relied on co-pollutant
reductions from the GHG emission standards to satisfy their compliance
obligations under the NAAQS for criteria pollutants. These commenters
argued that, given such reliance interests, the EPA should first
conclude its rescission of the Endangerment Finding, including any
subsequent litigation, before repealing the associated GHG emission
standards.
Response: The EPA acknowledges the comments and information
received from many States and local governmental entities, including
both the comments summarized above and comments from States urging us
to finalize the proposed rescission and repeals. We are aware that
State and local governments have, at various times, encouraged and
supported the EPA's GHG regulatory program and undertaken initiatives
to address perceived global climate change concerns. We disagree that
this final action disrupts State and local policy initiatives that have
used the Endangerment Finding or subsequent actions as a baseline,
however. So long as such policy initiatives are consistent with
applicable Federal law, they may continue, and nothing in this final
action changes the status quo for such initiatives. To the extent
commenters refer more generally to a practice of supporting and
imitating aspects of the EPA's GHG regulatory program, that practice
does not depend upon our continuing to maintain the program. To the
extent commenters refer to information, funding, or technical support
that has been integrated into such programs, we note that any such
provisions are not part of the Endangerment Finding or GHG emission
standards subject to rescission and repeal and that commenters did not
point to a specific counterexample that should be considered in this
rulemaking. Nothing in this final action addresses any separate
statutory obligation the EPA may have to provide information, make
grants, or provide technical support.
With respect to commenters' assertions about State and local
government investments in EV technology and infrastructure, we disagree
that such reliance interests counsel against the rescission and repeals
for substantially the same reasons discussed above regarding regulated
parties. Nothing in this final action precludes such investments, and
nothing in the prior actions and rules subject to this final action
entitled States or local governments to any particular benefits or
return on their investments. The extent to which such investments end
up supporting these entities' policy goals turns on a complex
combination of unrelated regulatory and economic factors.
Finally, with respect to the NAAQS program, we note that the EPA
has not established air quality criteria or NAAQS for GHGs under CAA
sections 108 and 109, either individually or under the Endangerment
Finding's definitional grouping of the six ``well-mixed'' GHGs. As
explained in section VI of this preamble, this final action does not
impact any of the EPA's criteria pollutant emission standards that are
more directly relevant to NAAQS attainment or NHTSA's separate fuel-
economy and fuel-efficiency regulations that also may result in co-
benefits. We acknowledge that many regulated parties elected to comply
with the GHG emission standards using technologies that also produce
reductions in criteria pollutant emissions, including by shifting
toward EVs or otherwise installing control equipment with co-benefits.
Nevertheless, we disagree that such co-benefits engender significant
reliance interests relevant to this rulemaking or that such
considerations justify retaining the GHG regulatory program in the
absence of statutory authority, particularly because the EPA has
additional, express statutory authorities to address criteria pollutant
emissions relevant to NAAQS attainment.
As a practical matter, criteria pollutant emission reductions
attributable to the GHG emission standards are small in absolute terms
and unlikely to materially impact States' attainment of the NAAQS. In
recent GHG emission standard rulemakings, we stated our expectation
that manufacturers would comply with the standards by shifting to EV
production, which we predicted would lower criteria pollutant emissions
from new motor vehicles, increase emissions from the power sector to
accommodate additional electricity demand, and marginally decrease
emissions attributed to fossil-fuel refineries given decreased demand
for diesel and gasoline. For the 2024 HD GHG Emission Standards Rule,
for example, we estimated small net decreases in NO<INF>X</INF>, VOCs,
and sulfur dioxide (SO<INF>2</INF>) emissions and a small net increase
in fine particulate matter (PM<INF>2.5</INF>) emissions.\91\ For
context, the emission decreases projected for HD vehicles amount to
less than 1 percent of national NO<INF>X</INF> emissions and less than
0.01 percent of VOC and SO<INF>2</INF> emissions for 2024.\92\ As
discussed above, this final action has the potential to alter vehicle
emissions on a prospective basis given the MY-by-MY nature of the
market and the applicability of CAA section 202(a) emission standards
to ``new'' motor vehicles and engines. Thus, any criteria pollutant
emission reductions realized in practice as a co-benefit of GHG
emission standards for

[[Page 7709]]

MY 2025 and earlier are not impacted by this final action. Moreover,
this final action does not require regulated parties to change existing
plans, but rather, provides additional flexibility moving forward,
meaning whether any and by how much anticipated reductions occur in
practice turns on decisions by multiple independent actors.
---------------------------------------------------------------------------

\91\ See, e.g., 89 FR 29440, 29455 (Apr. 22, 2024).
\92\ Compare id. (estimating NO<INF>x</INF>emission reductions
of 53,051 tons, VOC emission reductions of 7,272 tons, and
SO<INF>2</INF> emission reductions of 295 tons), with U.S.
Environmental Protection Agency: Air Pollutant Emissions Trends Data
(Apr. 2025) (estimating NO<INF>X</INF> emissions of 6,940,000 tons,
VOC emissions of 12,783,000 tons, and SO<INF>2</INF> emissions of
1,675,000 tons). National emissions are the appropriate comparator
because NAAQS attainment is evaluated by criteria pollutant levels
from all sources. Estimates in the 2024 HD GHG Emission Standards
Rule evaluated emissions from all HD vehicles MY 2027 and beyond
regardless of in-use location.
---------------------------------------------------------------------------

For these reasons, we cannot agree that States have significant
reliance interests in the permanence of GHG emission standards in
connection with NAAQS attainment. Potential impacts are limited to
marginal foregone emissions reductions in future years. The co-benefits
estimated in prior rulemakings are necessarily speculative because they
turn on compliance decisions by manufacturers in future years and
purchasing decisions by consumers (i.e., whether manufacturers comply
as expected by shifting to EVs or adopting different technologies, and
whether consumer demand for vehicles and engines, including relative
demand for traditional vehicles versus EVs, plays out as expected).
Reductions in such co-benefits are also uncertain because they depend
on how regulated parties choose to proceed in future years in light of
this final action. Separate and apart from this rulemaking, CAA section
202(a) makes clear that the content of the EPA's vehicle and engine
emission standards are subject to revision at any time, and we have
repeatedly revised the GHG emission standards for future MYs since
2010.\93\ See, e.g., Am. Fuel & Petrochemical Mfrs., 937 F.3d at 578
(finding reliance on particular biofuel volume decisions unreasonable
given the EPA's express discretion to revise requirements).
---------------------------------------------------------------------------

\93\ Unlike CAA sections 109, 111, 112, and 129, for example,
CAA section 202(a)(1) requires the EPA to revise new motor vehicle
and engine emission standards ``from time to time'' without
mandating a particular review timeline or date-certain deadline for
periodic revisions. Compare 42 U.S.C. 7521(a)(1), with id.
7409(d)(1), 7411(b)(1)(B), 7412(d)(6), (f)(2), 7429(a)(5).
---------------------------------------------------------------------------

The appropriate mechanisms for addressing these concerns are the
EPA's express statutory authorities bearing on criteria pollutant
emissions and the NAAQS. We encourage States to participate in future
rulemakings for criteria pollutant emission standards under CAA section
202 and other rulemakings impacting criteria pollutant emissions from
stationary sources. NAAQS attainment is evaluated based on measured
levels in the ambient air, and the statute provides a number of
regulatory tools to the EPA and States to promote attainment. For
example, the EPA may account for the impact of exceptional events and
international emissions under certain circumstances and require States
to adopt additional controls when their emissions contribute to
nonattainment in another State. And States have discretion in
formulating plans to attain the NAAQS, which may include certain
mobile-source compliance programs, additional controls for new and
existing stationary sources, and other emissions-reduction strategies.
For additional discussion of our efforts to assist States in attaining
the NAAQS, see the authorities, programs, and guidance documents
referenced in the Response to Comments document.
Comment: Commenters with a variety of perspectives asserted that we
failed to consider the interests of vehicle purchasers, including those
with future commitments to purchase clean vehicles and past purchasers
of vehicles with battery warranties and certain in-use performance
requirements. Several of these commenters also stated that current GHG
emission standards were projected to save consumers thousands of
dollars per vehicle in fuel costs over the life of the car given
continued improvements in efficiency and the availability of cleaner
vehicle models, including from increased EV market penetration.
Response: The EPA disagrees that such interests counsel against
finalizing the rescission and repeal and notes that commenters
misconstrue the impact of this final action and the requirements in the
GHG emission standards. Nothing in this final action requires regulated
parties to change existing plans, and that logic applies to future
purchase commitments as well. If States, municipalities, or businesses
wish to fulfill existing purchase requirements or choose to purchase
such vehicles in the future, they remain free to do so. Commenters
provided no reason to believe that these voluntary purchase agreements
were entered into to facilitate compliance with the GHG emission
standards, and we are not aware of any reason that States,
municipalities, or businesses not subject to the standards (i.e., not
manufacturers or suppliers) would be involved in the design or
production of compliance vehicles or engines. To the extent commenters
meant to assert that the purchases were intended to satisfy local
emission-reduction targets, many such targets are voluntary, and
nothing in this final action prevents entities from proceeding with or
adjusting existing strategies. With respect to past purchases, the
battery warranty and in-use performance requirements cited by
commenters are not set to begin until MY 2027. For this reason,
purchasers cannot reasonably have relied on these requirements for past
purchases, and any battery warranties or performance guarantees were
entered into on a voluntary basis separately from regulatory
requirements. See the Response to Comments document for additional
discussion of emissions warranties and limited additional ongoing
obligations for certain MY 2025 and earlier vehicles.
As to estimated fuel cost savings arising from the predicted
impacts of increased market penetration of EVs, we note that fuel costs
savings per vehicle for the consumer were not a substantive
justification for the Endangerment Finding. Rather, we included the
discussion cited by commenters in the RIAs completed for more recent
standards rulemakings. Commenters did not support their contention that
existing purchasers reasonably relied on the estimated fuel costs
savings per vehicle from the GHG emission standards in purchasing a
vehicle. Moreover, as discussed in the DRIA and RIA for this final
action, we significantly adjusted prior estimates of the cost savings
attributable to GHG emission standards. Our prior estimates were based
on interdependent assumptions and predictions regarding future choices
by unrelated actors and global fluctuations in fossil-fuel and energy
supply and demand. Intervening events since our estimates in 2024,
including legislative, policy, and global market changes, have already
demonstrated the significant range of uncertainty inherent in the
analysis. See the RIA for this final action and subsequent sections of
this preamble for further discussion.
Comment: Finally, several commenters argued generally that we
failed to consider reliance interests involving the U.S. economy,
national security, global geopolitics, and global trade. These
commenters argued that we must consider these interests to finalize a
valid rule.
Response: The EPA does not believe these general assertions raise
specific and legitimate reliance interests that could or must be taken
into account in this rulemaking as reliance interests. Case law
provides that such generalized concerns are not the type of reliance
interests that require special consideration.\94\ We endeavored to take

[[Page 7710]]

these general concerns into account in this rulemaking when
appropriate, including by carefully reviewing and considering the ways
in which Congress addressed international emissions issues in the CAA.
However, as discussed in section V of this preamble, the controlling
statutory language in CAA section 202(a) does not authorize the Agency
to regulate GHG emissions in response to such global concerns. The
possibility that interpreting CAA section 202(a) to authorize
regulation in response to global climate change concerns would render
the statute broad enough to encompass global political and economic
relations reinforces our view of the best reading of the statute.
---------------------------------------------------------------------------

\94\ See, e.g., Am. Petrol. Inst., 81 F.4th at 1061 (``general
assertions of reliance simply do not rise to the level of ongoing
and serious reliance interests necessary to trigger a duty . . . to
provide a more detailed explanation''); Am. Hosp. Ass'n v. Azar, 983
F.3d 528, 540 (D.C. Cir. 2020) (rejecting general assertion of
reliance interests where party ``identified no reliance interests
the action might be upending'').
---------------------------------------------------------------------------

B. Repeal of New Motor Vehicle and Engine GHG Emission Standards

As noted above, CAA section 202(a)(1) directs the Administrator to
prescribe ``standards applicable to the emission of any air pollutant
from any class or classes of new motor vehicles or new motor vehicle
engines, which in his judgment cause, or contribute to, air pollution
which may reasonably be anticipated to endanger public health or
welfare.'' This core directive has remained substantially the same
since Congress enacted the Motor Vehicle Pollution Control Act of
1965.\95\ Thus, a necessary condition to regulating emissions from new
motor vehicles and engines is a finding--an ``endangerment finding''--
that emissions of an air pollutant from a class or classes of new motor
vehicles or engines cause or contribute to air pollution which may
reasonably be anticipated to endanger public health or welfare.
---------------------------------------------------------------------------

\95\ Public Law 89-272, 79 Stat. 992, 992-93.
---------------------------------------------------------------------------

For the reasons discussed in sections V.A and V.B of this preamble,
we are rescinding the Endangerment Finding for GHG emissions from new
motor vehicles and new motor vehicle engines and, on that basis,
repealing all existing GHG emission standards for passenger cars,
light-duty trucks, motorcycles, buses, medium-duty vehicles, and heavy-
duty vehicles and engines. The Endangerment Finding has served as the
EPA's basis for regulating GHG emissions from new motor vehicles and
new motor vehicle engines since 2009. Absent findings of endangerment
and causation or contribution, the EPA lacks statutory authority to
prescribe standards for those emissions under CAA section 202(a)(1).
Thus, we must cease prescribing and enforcing standards applicable to
the emission of that pollutant from new motor vehicles or new motor
vehicle engines and are rescinding existing standards no longer
authorized by statute.
For the reasons discussed in section V.C of this preamble, we also
find that the futility of GHG emission standards for new motor vehicles
and engines warrants repealing the standards separate and apart from
the rescission of the Endangerment Finding. Courts have long recognized
the background principle that Congress does not intend agencies to
expend resources on fruitless efforts, particularly when those efforts
come at the expense of express statutory obligations for which material
progress is more readily achievable. Given the immense costs to
manufacturers, auto workers, and American consumers, as well as the
burden of administration placed on the EPA and other relevant Federal
and State entities, it would be unreasonable to retain a regulatory
program that does not materially further any statutory objective
relevant to the global climate change concerns relied upon by the
Agency in the 2009 Endangerment Finding. This conclusion is consistent
with the precautionary nature ascribed by relevant

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