[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 [www.gpo.gov]
[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 www.regulations.gov 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 www.epa.gov/dockets.
Public Participation: Docket: All documents in the docket are
listed on the www.regulations.gov 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: [email protected].
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
CH4 Methane
CI Confidence interval
cm Centimeter
CO Carbon monoxide
CO2 Carbon dioxide
CO2e 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
N2O 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 + NOX Nonmethane organic gases and oxides of
nitrogen
NO2 Nitrogen dioxide
NOX Oxides of nitrogen
NTTAA National Technology Transfer and Advancement Act
O3 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
PM2.5 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
SF6 Sulfur hexafluoride
SIP State Implementation Plan
SO2 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 https://www.epa.gov/regulations-emissions-vehicles-and-engines/final-rule-rescission-greenhouse-gas-endangerment. 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 (CO2), methane, nitrous oxide
(N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs),
and sulfur hexafluoride (SF6)--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--CO2, methane, N2O, 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: https://doi.org/10.2760/953322.
\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 CO2 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 https://ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/land_ocean/tavg/ytd/12/1950-2025.
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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.
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\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.
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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\
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\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.
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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 https://www.epa.gov/newsreleases/trump-epa-kicks-formal-reconsideration-endangerment-finding-agency-partners.
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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\
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\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.
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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, NOX, sulfur oxides
(SOX), 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.
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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).
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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).
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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 https://www.epa.gov/system/files/documents/2022-04/decision_document.pdf.
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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).
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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 (NOX),
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).
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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--
CO2, methane, N2O, 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
``CO2 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 CO2 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
CO2 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 CO2,
methane, and N2O emissions and noted that HFCs, PFCs, and
SF6 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 CO2 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 CO2 emissions, for example, generally
increasing since 1990 and N2O 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],
N2O, HFCs, PFCs and SF6 is about 40% as large
as the CO2 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
SF6--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 CO2) 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.
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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--CO2, methane, and N2O 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).
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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\
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\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.
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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\
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\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.).
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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\
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\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).
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[[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\
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\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.'').
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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\
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\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.
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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\
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\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.
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\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).
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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\
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\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).
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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.
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\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)).
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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 CO2
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).
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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\
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\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.
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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.
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\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'').
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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.
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\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\
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\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).
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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.
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\89\ See 40 CFR 86.1865-12(k)(2) (``There are no property rights
associated with CO2 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).
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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 NOX, VOCs,
and sulfur dioxide (SO2) emissions and a small net increase
in fine particulate matter (PM2.5) emissions.\91\ For
context, the emission decreases projected for HD vehicles amount to
less than 1 percent of national NOX emissions and less than
0.01 percent of VOC and SO2 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.
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\91\ See, e.g., 89 FR 29440, 29455 (Apr. 22, 2024).
\92\ Compare id. (estimating NOxemission reductions
of 53,051 tons, VOC emission reductions of 7,272 tons, and
SO2 emission reductions of 295 tons), with U.S.
Environmental Protection Agency: Air Pollutant Emissions Trends Data
(Apr. 2025) (estimating NOX emissions of 6,940,000 tons,
VOC emissions of 12,783,000 tons, and SO2 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.
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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).
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\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'').
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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 court decisions to
the statutory language of CAA section 202(a)(1), which we recognize
does not require showing that emission standards entirely or even
substantially address the identified dangers. Rather, the available
information indicates that GHG emission standards have no impact at all
on the adverse impacts identified in the Endangerment Finding beyond a
de minimis level that falls well below inherent variability in
measurements of GMST and GSLR.
Accordingly, the EPA is repealing all standards and associated test
procedures adopted to limit the emission of GHGs under CAA section
202(a)(1) for highway LD, MD, and HD vehicles and engines. The EPA
notes that, for LD vehicles, the Energy Policy and Conservation Act of
1975 (EPCA) \96\ and the 2007 EISA authorize NHTSA to administer the
CAFE program and fuel economy labeling program. These statutes also
direct the EPA to determine compliance values for manufacturers subject
to the CAFE program and the fuel economy labeling program. Importantly,
these statutory obligations are distinct from the EPA's authority under
CAA section 202(a) and from the EPA's decisions since 2009 to regulate
GHG emissions under CAA section 202(a). As explained in section VII of
this preamble, we did not propose to reopen and are not finalizing in
this rulemaking any changes to regulatory provisions related to our
statutory roles in these NHTSA programs. Likewise, we did not propose
to reopen and are not finalizing in this rulemaking any changes to
criteria pollutant and air toxics standards for highway LD, MD, and HD
vehicles and engines under CAA section 202(a).
---------------------------------------------------------------------------
\96\ Public Law 94-163, 89 Stat. 871 (1975).
---------------------------------------------------------------------------
V. Rescission of the Endangerment Finding
In this section, the EPA provides its bases for rescinding the 2009
Endangerment Finding that initiated the Agency's unprecedented
assertion of authority to regulate GHG emissions in response to global
climate change concerns. Upon careful review of the text, structure,
and history of CAA section 202(a)(1) and related provisions and
consideration of comments received on the rationales set out in
sections IV.A and V.C of the preamble to the proposed rule, we are
finalizing that the Endangerment Finding and GHG regulatory program for
new motor vehicles and engines exceeds the EPA's statutory authority
for multiple, independent reasons. This conclusion leads us to finalize
the proposed repeal of the GHG emission standards in the relevant
provisions of Title 40 of the CFR as detailed in section VII of this
preamble.
Section V.A of this preamble sets out our determination that CAA
section 202(a) does not authorize the EPA to prescribe standards for
GHG emissions based on global climate change concerns. Consistent with
the Agency's practice before 2009, we conclude that this provision
contains important limitations on what would otherwise be a boundless
authority. First, CAA section 202(a)(1) is best read as authorizing the
EPA to identify and regulate ``air pollution'' that threatens to
endanger health and welfare through local and regional exposure.
Second, CAA section 202(a)(1) is best read as requiring the EPA to
apply the statutory standard for regulation as a whole by issuing
findings as an integral predicate step of an emission standards
rulemaking and, in doing so, evaluating whether new motor vehicle and
engine emissions cause or contribute to the danger posed by the
relevant air pollution. We apply the traditional tools of statutory
interpretation to CAA section 202(a)(1) and related provisions, as
informed by the Supreme Court's decisions in Loper Bright and UARG. We
also explain how the inability of GHG emission standards to have a
material (i.e., non-de minimis) impact on the dangers attributed to
global climate change in the Endangerment
[[Page 7711]]
Finding informs our statutory interpretation.
Section V.B of this preamble explains our determination that CAA
section 202(a)(1) lacks the clear congressional authorization required
for the EPA to assert authority to regulate GHG emissions in response
to global climate change concerns. We review the Supreme Court's
precedents applying the major questions doctrine, including UARG and
West Virginia, to conclude that the Nation's policy response to global
climate change concerns is a question of significant economic and
political importance and that Congress did not clearly empower the EPA
to decide by authorizing the Administrator to ``prescribe . . .
standards'' for emissions from new motor vehicles and engines. We
further explain that a limiting construction of CAA section 202(a)(1)
is necessary to avoid serious constitutional concerns with the breadth
of the provision required by the logic adopted in the Endangerment
Finding.
Section V.C of this preamble explains our determination, informed
by comments and supporting data received in response to the proposed
rule, that GHG emission standards have not and cannot materially
diminish the health and welfare impacts attributed to global climate
change by the Endangerment Finding in any non-de minimis way. As
presented below, the results of our modeling indicate that even the
elimination of all GHG emissions from vehicles in the United States
(both new and existing, and inclusive of LD, MD, and HD vehicles) would
not yield impacts beyond a level that is well below the range of
inherent variability in measurement for trends in GMST and GSLR. We
conclude that these findings lend further support to the basis for
rescission in section V.A of this preamble given the language of CAA
section 202(a)(1) and the background principles that Congress does not
require futile efforts or include de minimis concerns in general
statutory terms. We further conclude that these findings support
repealing the GHG emission standards separate and apart from the
rescission of the Endangerment Finding because it is unreasonable to
impose immense costs that do not further any legitimate statutory
purpose.
Each of the legal bases finalized in this action is separate and
independent from the others, and the EPA would rescind the Endangerment
Finding and repeal the GHG emission standards on any one of these bases
standing alone. The EPA's lack of statutory authority for the
Endangerment Finding and related regulations would require rescission
and repeal even if the major questions doctrine did not apply.
Similarly, the major questions doctrine would require finalizing this
action even if the EPA had a plausible textual basis for asserting the
authority to regulate GHG emissions in response to global climate
change concerns. Each of these bases would require finalizing this
action even if the futility of the GHG emission standards program were
not established in the record or were not an adequate basis for this
final action. Conversely, the futility of the GHG emission standards
program would support repealing the GHG emission standards even if
there were an adequate legal basis to retain the Endangerment Finding.
``Wisdom too often never comes, and so one ought not to reject it
merely because it comes late.'' Henslee v. Union Planters Nat'l Bank &
Tr. Co., 335 U.S. 595, 600 (1949) (Frankfurter, J., dissenting).
Because the Endangerment Finding and the regulations that rely upon it
exceed the EPA's authority in multiple respects, fundamental legal
principles underpinning our constitutional system compel corrective
action. The Endangerment Finding must be rescinded, and the regulatory
program it initiated must be, repealed.
A. Best Reading of CAA Section 202(a)(1)
The Endangerment Finding announced an interpretation of CAA section
202(a)(1) that permitted the EPA to prescribe standards in response to
global climate change concerns rather than air pollution that threatens
public health or welfare through local or regional exposures. We
asserted that the statute's ``silence'' granted us ``procedural
discretion'' to issue standalone findings without considering the
regulatory response required by those findings. In setting out our
standalone findings, we severed the endangerment analysis (based on
health and welfare harms attributed primarily to trends in GMST and
GSLR) from the cause or contribution analysis (based on the estimated
share of domestic GHG emissions from all new and existing motor
vehicles and engines in global GHG emissions from all anthropogenic
sources). In the endangerment analysis, we acknowledged that none of
the health effects of concern were associated with direct exposure to
GHGs, and in the contribution analysis, we acknowledged that combatting
the identified risks would require all contributors--both domestic and
international and from all anthropogenic sources--to ``do their part.''
Throughout, we assumed that the Supreme Court's decision in
Massachusetts compelled us to read the statute as authorizing the
regulation of GHG emissions under CAA section 202(a)(1).
In important respects, the Endangerment Finding and the Supreme
Court's decision in Massachusetts straddled a transitional period
regarding the standards for statutory interpretation and understandings
of agency authority. The breadth of agency discretion, and the question
whether Congress reserves major policy questions for itself, were
sharply disputed. Judicial decisions in the intervening fifteen years
have significantly clarified the law. In Loper Bright, the Supreme
Court overruled the Chevron doctrine of deference to agency statutory
interpretation, ruling that statutes ``have a single, best meaning''
that is ```fixed at the time of enactment''' and informed, but not
dictated, by Executive Branch practice. 603 U.S. at 400-01 (quoting
Wis. Cent. Ltd. v. United States, 585 U.S. 274, 284 (2018)). And in
West Virginia, the Supreme Court built upon its decisions in UARG and
Brown & Williamson, among others, by confirming that an agency must
have more than ``a colorable textual basis'' to claim authority to
decide major questions of policy that Congress generally reserves for
itself. 597 U.S. at 723.
In this subsection, we explain that the best reading of CAA section
202(a)(1), as informed by Loper Bright and principles of statutory
interpretation, does not authorize the EPA to assert jurisdiction over
GHG emissions based on global climate change concerns in a standalone
endangerment finding. Scientific understanding of environmental issues
may be continuously evolving, but the scope of the EPA's authority
under CAA section 202(a)(1) is fixed by the terms Congress used when
enacting and amending the language of CAA section 202(a)(1) from 1965
to 1977. Regardless whether GHGs are ``agents of air pollution'' under
the Act-wide definition of ``air pollutant'' in CAA section 302(g), we
cannot regulate under CAA section 202(a) unless emissions of the air
pollutant by new motor vehicles and engines ``cause, or contribute to,
air pollution which may reasonably be anticipated to endanger public
health or welfare.'' Because the ordinary meaning, structure, and
history of CAA section 202(a)(1) and related provisions demonstrate
that this language targets ``air pollution'' that threatens public
health or welfare through local or regional exposure, the ``six well-
mixed'' GHGs defined by reference to global climate change concerns
cannot satisfy this standard. The futility of GHG emission standards in
addressing the
[[Page 7712]]
health and welfare impacts attributed to global climate change further
reinforces this interpretation. For these reasons, and on account of
the additional procedural and analytical errors discussed below, we are
rescinding the Endangerment Finding.
1. Final Rationale
Congress originally enacted the language of CAA section 202(a) in
the Motor Vehicle Pollution Control Act of 1965 and retained it, with
minor revisions, in 1967, the 1970 CAA, and the 1977 amendments. The
key language in CAA section 202(a)(1) provides:
The Administrator shall by regulation prescribe (and from time
to time revise) in accordance with the provisions of this section,
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.\97\
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\97\ 42 U.S.C. 7521(a)(1). The key terms ``cause, or
contribute,'' ``air pollution,'' ``endanger,'' and ``health or
welfare'' were introduced in 1965. Public Law 89-271, section 101,
79 Stat. 992, 992-93. The phrase ``may reasonably be anticipated
to'' was added to the earlier phrase ``which endangers the public
health or welfare'' in 1977. Public Law 95-95, section 401(d)(1), 91
Stat. 685, 791.
Since 1977, CAA section 302(g) has defined the term ``air
pollutant'' throughout the statute as ``any air pollution agent or
combination of such agents . . . which is emitted into or otherwise
enters the ambient air.'' \98\ CAA section 302(h) also provides that
any reference to ``effects on welfare includes, but is not limited to,
effects on'' the environment, property, transportation hazards, and
``on economic values and on personal comfort and well-being.'' \99\
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\98\ 42 U.S.C. 7602(g). Notably, the statute does not separately
define ``air pollution.''
\99\ 42 U.S.C. 7602(h). This definition took its current form in
the 1970 CAA and was amended in part in the 1990 CAA Amendments to
add the final clause ``whether caused by transformation, conversion,
or combination with other air pollutants.'' See Public Law 91-604,
84 Stat. 1676, 1710; Public Law 101-549, 104 Stat. 2399, 2470.
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The EPA concludes that this statutory language is best read as
authorizing the Agency to identify and regulate, as an integral part of
a rulemaking prescribing emission standards, emissions that cause or
contribute to air pollution that endangers public health and welfare
through local or regional exposure. This reading is consistent with the
ordinary meaning of key terms and the statutory structure, our decades-
long implementation of the statute prior to 2009, and background
principles of statutory interpretation, including default rules for
proximate cause. This reading is also consistent with the Supreme
Court's decision in Massachusetts, which addressed distinct issues
arising out of the denial of a petition for rulemaking and must, as a
matter of stare decisis, be read in harmony with subsequent decisions
bearing on the EPA's authority and statutory interpretation, including
UARG, West Virginia, and Loper Bright.
Air Pollution. The EPA is finalizing as proposed that CAA section
202(a)(1) is best read as authorizing the Agency to regulate emissions
that cause or contribute to air pollution that endangers public health
or welfare through local or regional exposure. For the purposes of this
final action, we use the phrase local or regional exposure to
distinguish air pollution that impacts public health and welfare by its
presence in the ambient air from ``air pollution'' consisting of six
``well-mixed'' GHGs that, as conceptualized in the Endangerment
Finding, impacts public health and welfare only indirectly and not by
its mere presence in the ambient air. As discussed below, this aspect
of the final action effectively returns the EPA to its interpretation
of CAA section 202(a)(1) prior to 2009 and the ordinary meaning of the
terms Congress selected.
In CAA section 202(a)(1), Congress identified the object of the
regulatory authority conferred in the remainder of the section--``air
pollution which may reasonably be anticipated to endanger public health
or welfare.'' The EPA's emission standards for new motor vehicles and
engines were a key part of the congressional design for combatting air
pollution problems impacting the Nation throughout the 1960s and 1970s,
particularly in high-population areas. Congress debated these issues
extensively in advance of the 1970 CAA by reference to the air
pollution impacting Americans every day, with smog, criteria
pollutants, and air toxics taking center stage.\100\ To address the
perceived need for a rapid response, Congress paired the preexisting
language imported into CAA section 202(a)(1) \101\ with new language in
CAA section 202(b)(1) requiring that emission standards contain
significant, short-term reductions in CO, HC, and NOX
emissions from new LD vehicles and engines.\102\ As discussed elsewhere
in this preamble, Congress repeatedly returned to this strategy in the
subsequent decades by adding language to CAA section 202 requiring that
emission standards achieve further reductions for additional pollutants
and classes of new motor vehicles and engines.
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\100\ See, e.g., S. Rep. 91-1196, at 1, 7 (1970) (expressing
``concern with direct adverse effects upon public health'' and the
need for ``definitive knowledge of the causal relationships between
exposure to air pollution agents . . . and health or welfare under
varying environmental conditions,'' particularly by reference to
SOx, PM, CO, HC, and oxidants and the role of mobile
sources in urban pollution); id. at 18 (describing the three general
categories of air pollution as criteria pollutants, hazardous air
pollutants, and certain emissions unique to stationary sources);
H.R. Rep. 91-1146, at 6 (1970) (explaining that mobile-source air
pollution ``is particularly dangerous in the highly urbanized areas
of our country''); 116 Cong. Rec. 32902 (1970) (statement of Sen.
Muskie) (explaining that the draft legislation targeted mobile-
source contribution to urban pollution, including by requiring
``emission standards for carbon monoxide, hydrocarbons, and nitrogen
oxides''); see also 111 Cong. Rec. 10782 (1965) (statement of Sen.
Muskie) (similarly emphasizing in advance of the original 1965
legislation that mobile sources accounted for ``50 percent of our
national air pollution problem'' and focusing in particular on
``carbon monoxide,'' ``hydrocarbons,'' and ``nitrogen oxides'').
\101\ See, e.g., S. Rep. 91-1196, at 24 (``The regulatory
authority in section 202(a) would be essentially the same as
existing law . . . .''); H.R. Rep. 91-1783 (1970) (conf. report)
(explaining that the House largely acceded to the Senate bill in
relevant part).
\102\ Public Law 91-604, section 6(a), 84 Stat. 1676, 1690. In
subsequent amendments, Congress modified and expanded upon the
provisions in CAA section 202(b)(1) to require that emission
standards achieve further reductions for later model years. See 42
U.S.C. 7521(b)(1).
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Particularly in light of this history, the term ``air pollution''
as used in CAA section 202(a)(1) must be construed in context with the
specific air pollutants and air pollution concerns identified in the
remainder of CAA section 202. Each of these listed pollution control
targets share the common quality of causing or contributing to air
pollution that adversely impacts public health or welfare through local
or regional exposure to the air pollution itself. CAA section 202
specifically requires the EPA to prescribe emission standards with
various minimum content for HCs, CO, NOX, and PM, all of
which harm human health and the environment through exposure (e.g.,
inhalation and dermal contact) or by causing or contributing to air
pollution that harms health and the environment through exposure (e.g.,
smog and acid rain).\103\ CAA section 202(l) also requires prescribing
emission standards under CAA section 202(a)(1) for certain air
pollutants that qualify as ``toxic'' or ``hazardous'' air pollutants,
including benzene and formaldehyde.\104\ Neither GHGs nor any of the
individual ``six well-mixed'' GHGs defined in the Endangerment Finding
by reference to global climate change concerns appear
[[Page 7713]]
anywhere in CAA section 202.\105\ That pattern holds for the criteria
pollutants identified in the CAA--CO, lead, ozone (O3),
nitrogen dioxide (NO2), PM, and SO2--as well as
the initial list of hazardous air pollutants in CAA section
112(b)(1).\106\
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\103\ See, e.g., 42 U.S.C. 7521(a)(3)(A)(i), (b), (g), (h), (j),
(k).
\104\ 42 U.S.C. 7521(l). Such regulations may include fuel
standards under issued under the EPA's fuel and fuel additive
authority in CAA section 211.
\105\ Notably, in the last major amendments to the Clean Air Act
in 1990, Congress specified ``nonmethane hydrocarbons (NMHC)'' when
adding additional minimum requirements for HC, CO, NOX,
and PM emission standards at CAA section 202(g) and (h). Public Law
101-549, section 203, 104 Stat. 2399, 2474 (emphasis added)
(codified at 42 U.S.C. 7521(g), (h)).
\106\ 42 U.S.C. 7412(b)(1).
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We find it significant that in subjecting a number of air
pollutants emitted by new motor vehicles and engines to regulation
under CAA section 202, Congress did not include substances that are
potentially indirectly harmful to public health or welfare based on
elevated global concentrations in the upper atmosphere. That
conspicuous omission supports the conclusion that emissions subject to
regulation under CAA section 202(a) are those that cause or contribute
to air pollution which itself endangers public health or welfare
through local or regional exposure.\107\ For certain regulated air
pollutants, the emissions themselves are the air pollution that
endangers public health or welfare, i.e., emissions are the air
pollution with adverse health and welfare impacts. An example is CO,
which can be harmful, and even fatal, to humans at sufficient localized
concentrations.\108\ For other regulated air pollutants, emissions
contribute to air pollution that endangers public health or welfare by
interacting with other airborne chemicals or environmental factors such
as sunlight to create the air pollution that endangers public health or
welfare, i.e., the emitted air pollutants are ingredients that create
the air pollution that endangers public health or welfare in
combination. An example is acid rain, in which air pollutants such as
SO2 interact locally and regionally with additional airborne
chemicals to form acidic precipitation.\109\ Another example is
NOX, which reacts with VOCs in the presence of heat and
sunlight to create ground-level ozone as the airborne chemicals are
carried by wind over geological features amenable to ground-level ozone
formation.\110\
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\107\ As discussed herein, the references to GHGs in the CAA are
in non-regulatory contexts in which Congress authorized funding for
various forms of research and grant programs and the Renewable Fuel
Standard (RFS) program. The choice to limit such references to non-
regulatory solutions and the RFS program, which applies to refiners
and importers, further supports the conclusion that the CAA section
202(a) regulatory authority for responding to endangerment does not
encompass GHG emissions in connection with global climate change
concerns.
\108\ U.S. Environmental Protection Agency. (Last updated Oct.
7, 2025). Carbon Monoxide's Impact on Indoor Air Quality: https://www.epa.gov/indoor-air-quality-iaq/carbon-monoxides-impact-indoor-air-quality.
\109\ U.S. Environmental Protection Agency. (Last updated Mar.
4, 2025). What is Acid Rain?: https://www.epa.gov/acidrain/what-acid-rain.
\110\ U.S. Environmental Protection Agency. (Last updated Mar.
11, 2025). Ground-level Ozone Basics: https://www.epa.gov/ground-level-ozone-pollution/ground-level-ozone-basics.
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We also emphasize that expanding CAA section 202(a)(1) to encompass
global climate change concerns required the EPA to take the admittedly
``unique'' approach of finding endangerment and contribution where the
overwhelming majority of relevant emissions hails from international
sources. Although we justified this approach by concluding as a policy
matter that all sources must ``do their part'' to avoid a collective
action problem, Congress has specifically provided in the CAA when and
how the EPA may consider international emissions. For example, CAA
section 115 authorizes the EPA to require controls for domestic
emissions that contribute to air pollution that endangers public health
or welfare in another country only when, among other things, that
country has adopted reciprocal protections for emissions into the
United States.\111\ CAA section 179B authorizes the EPA to account for
the impact of international emissions on NAAQS attainment under certain
conditions.\112\ Most importantly, Congress adopted a new regulatory
regime in 1990--Title VI--in response to global concerns about
depletion of the ozone layer, which contains its own findings,
policies, and regulatory authorities that required the EPA to phase out
domestic use of ozone-depleting substances.\113\ None of these
provisions encompass GHG emissions, and all support the conclusion that
Congress does not presume that general authorities in the CAA encompass
international emissions. Rather, Congress knows how to provide for the
consideration of and regulation in response to international emissions,
and has not done so for GHG emissions in the CAA section 202 provisions
governing new motor vehicle and engine emissions.
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\111\ 42 U.S.C. 7415.
\112\ 42 U.S.C. 7509a.
\113\ 42 U.S.C. 7671 et seq.
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The definition of ``air pollutant'' in CAA section 302(g) and the
ordinary meaning of the undefined terms pollutant, pollution, and air
pollution support this reading. At the time Congress added these terms
to CAA section 202(a)(1), the term ``pollutant'' was defined as
``[a]nything that pollutes; especially, any gaseous, chemical, or
organic waste that contaminates air, soil, or water,'' \114\ and
``pollution'' was defined as ``[t]he contamination of soil, water or
the atmosphere by the discharge of noxious substances.'' \115\ The
definition of the root word ``pollute''--``[t]o dirty, contaminate,''
confirms the relationship of these terms to concepts of contamination
and toxicity.\116\ The central concept is the addition of a
contaminant, something that ``make[s] impure by contact or mixture.''
\117\ CAA section 302(g) defines ``air pollutant'' is any ``air
pollution agent or combination of such agents'' that ``is emitted into
or otherwise enters the ambient air.'' \118\ Read together with CAA
section 202(a)--as the Supreme Court held we must in UARG--the
underlying concept of dangerousness and contamination reinforces the
conclusion that air pollution which endangers public health or welfare
is air pollution (caused or contributed to by air pollutants) that
itself endangers public health or welfare through local or regional
exposures.
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\114\ Pollutant, Am. Heritage Dictionary 1015 (1970); see also
Pollutant, 3 Webster's Third New Int'l Dictionary 1756 (1966)
(``something that pollutes: a polluting substance, medium or
agent'').
\115\ Pollution, Am. Heritage Dictionary 1015 (1970); see also
Pollution, 3 Webster's Third New Int'l Dictionary 1756 (1966) (``the
action of polluting or the state of being polluted: defilement,
desecration, impurity, uncleanness'').
\116\ Pollute, Am. Heritage Dictionary 1015 (1970); see also
Pollute, Black's Law Dictionary 1043 (5th ed 1979) (``To corrupt or
defile. The contamination of soil, air and water by noxious
substances and noises.''); Pollute, 3 Webster's Third New Int'l
Dictionary 1756 (1966) (``to make physically impure or unclean:
befoul, dirty, taint'').
\117\ Contaminate, Am. Heritage Dictionary 156 (1970); see also
Contaminate, 1 Webster's Third New Int'l Dictionary 491 (1966) (``to
soil, stain, corrupt, or infect by contact or association'').
\118\ 42 U.S.C. 7602(g).
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Contemporaneous usage of the term ``air pollution'' in the 1960s
and 1970s further indicate the term was understood in this way when
Congress adopted it into Title II of the CAA. Judicial decisions issued
close in time to the public debates and enactment of the CAA Amendments
of 1970 used the term exclusively in reference to local and regional
exposure.\119\ News reports
[[Page 7714]]
and legislative debates leading up to the 1970 Amendments similarly
attacked air pollution problems arising from local and regional
exposure, including smog and health and welfare impacts related to
inhalation and physical contact.\120\ This pattern of usage is
consistent with subsequent legislative amendments to CAA section 202,
which added provisions specific to criteria pollutants and air toxics
fitting this profile, and with the EPA's course of mobile-source
regulation until 2009. In reviewing the relevant history, including
materials received during the public comment period, we have not
identified an authoritative source suggesting that the ordinary meaning
of ``air pollution'' would have included, without additional modifying
language, gases that may endanger public health or welfare only on a
global scale and through an attenuated and indirect causal chain.
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\119\ See, e.g., Washington v. GM Corp., 406 U.S. 109, 115-16
(1972) (declining to exercise original jurisdiction over complaint
alleging conspiracy to restrain the development of air pollution
control devices for motor vehicles because, although ``Congress has
largely preempted the field with regard to `emissions from new motor
vehicles,' . . . geophysical characteristics which define local and
regional airsheds are often significant considerations in
determining the steps necessary to abate air pollution''); Friends
of Earth v. FCC, 449 F.2d 1164, 1165-66 (D.C. Cir. 1971) (addressing
challenge to the FCC's treatment of automobile advertisements that
petitioners alleged took a position on motor vehicle air pollution
worsening local conditions in New York City, including ``dangerous
hydrocarbons in the air'').
\120\ See, e.g., Coal. for Responsible Regulation, 2012 U.S.
App. LEXIS 25997, at *32-37 (Brown, J., dissenting from denial of
rh'g en banc) (summarizing relevant history).
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The ``air pollution'' addressed in the Endangerment Finding is
different in kind. In that decision, the Administrator defined the
relevant ``air pollutant'' as six ``well-mixed GHGs'' and the relevant
``air pollution'' as total global concentrations of ``the combined mix
of'' these GHGs ``which together, constitute the root cause of human-
induced climate change and the resulting impacts on public health and
welfare.'' 74 FR 66516. In contrast to the air pollution addressed
expressly in CAA section 202 and elsewhere in the statute, GHGs do not
endanger public health or welfare through local or regional exposure.
Rather, the Endangerment Finding asserted that GHG ``air pollution''
would lead to increases in global temperature and change to ocean pH
that, in turn, would lead to environmental phenomena, in combination
with an open-ended universe of additional factors, which would
potentially have adverse health and welfare impacts of varying severity
in certain regions. Indeed, the Administrator expressly admitted at the
time that the circumstances were ``unique'' because ``[n]one of th[e]
human health effects'' identified in the Endangerment Finding ``are
associated with direct exposure to greenhouse gases.'' 74 FR 66527.
With respect to welfare effects, the Administrator acknowledged that
the primary effects of concern could be considered health or welfare
impacts \121\ and that certain welfare impacts were ``effects on people
that do not rise to the level of health effects'' but utilize the same
causal chain. 74 FR 66527; see 74 FR 66531 (explaining that the
Endangerment Finding considered the same causal ``pathways'' in
analyzing ``public health'' and ``public welfare'').\122\ Regulating
GHG emissions based on global climate change concerns requires reading
an additional instance of ``cause, or contribute'' into the statute,
such that CAA section 202(a) encompasses the `emission of air
pollutants that cause, or contribute to, air pollution that causes, or
contributes to, endangerment of public health or welfare.'
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\121\ For example, the EPA in the Endangerment Finding
understood impacts on ``well-being'' as used in the CAA section
302(h) definition of ``welfare'' to be relevant ``whether [the
impacts] resul[t] directly or indirectly from the pollution in the
air.'' 74 FR 66528.
\122\ The Agency acknowledged that difficult questions about the
distinction between health and welfare impacts was something the
``EPA has not had to resolve'' in the past, ``as it has been clear
whether the effects relate to public health or relate to public
welfare, with no confusion over what category was at issue.'' 74 FR
66527. Rather than take this analytical difficulty as a sign that
the causal chain was different in kind from the type of ``air
pollution'' addressed by CAA section 202(a)(1), however, we
proceeded to finalize a novel invocation of authority to regulate in
response to global climate change concerns.
---------------------------------------------------------------------------
This interpretation is also supported by the best reading of the
terms ``cause,'' ``contribute,'' and ``reasonably be anticipated to
endanger.'' In enacting and amending CAA section 202(a)(1), Congress
legislated against background legal principles, including principles of
causation and proximate cause.\123\ These ``default rules'' are
``presumed to have [been] incorporated, absent an indication to the
contrary in the statute itself,'' \124\ and nothing in the text of CAA
section 202(a)(1) indicates that Congress intended to depart from
ordinary legal meaning. Indeed, Congress affirmatively incorporated
proximate cause principles when it added the phrase ``may reasonably be
anticipated'' to the statute in 1977 amendments to the CAA. That
phrasing is another way of saying ``reasonably foreseeable,'' a
longstanding touchstone of proximate cause.\125\ As a general matter,
there is a point at which harm no longer has a sufficiently close
connection to the relevant conduct to reasonably draw a causal link.
Emissions from new motor vehicles and new motor vehicle engines in the
United States do not have a sufficiently close connection to the
adverse impacts identified in the Endangerment Finding to fit within
the legal meaning of ``cause'' or ``contribute.'' This reading is
complemented by the term ``reasonably'' in the phrase ``air pollution
which may reasonably be anticipated to endanger public health or
welfare.'' Like the terms ``cause'' and ``contribute,'' the term
``reasonably'' places an outer legal limit on the authority to
anticipate dangers to public health and welfare from air pollution. The
greater the number of causal links involved in anticipating such
endangerment, the more difficult it is to qualify that anticipation as
``reasonable.''
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\123\ See, e.g., Bank of Am. Corp. v. City of Miami, 581 U.S.
189, 201 (2017); Lexmark Int'l, Inc. v. Static Control Components,
Inc., 572 U.S. 118, 132 (2014); Univ. of Tex. Sw. Med. Ctr. v.
Nassar, 570 U.S. 338, 347 (2013); City of Oakland v. Wells Fargo &
Co., 14 F.4th 1030 (9th Cir. 2021) (en banc).
\124\ Nassar, 570 U.S. at 347.
\125\ Foreseeable, 1 Webster's Third New Int'l Dictionary 890
(1966) (``being such as may reasonably be anticipated''); see, e.g.,
Hicks v. United States, 511 F.2d 407, 421 (D.C. Cir. 1975) (finding
``proximate cause'' satisfied because it was ``foreseeable'' that a
hospital's release without warning of an alcoholic patient with a
history of abusing his wife could result in harm to the patient's
wife).
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Notably, contemporary understandings of terms used in the CAA
section 302(h) definition of ``welfare'' also support the understanding
that CAA section 202(a)(1) encompasses air pollution with adverse
impacts from local or regional exposure. The statute provides that
references to ``effects on welfare'' include ``effects on soils, water,
crops, vegetation, manmade materials, animals, wildlife, weather,
visibility, and climate,'' damage to property, transportation hazards,
and effects on economic values and personal comfort and well-being. The
ordinary meaning of ``climate,'' an undefined term, was ``[t]he
prevailing weather in a particular region'' or ``[a] region manifesting
particular meteorological conditions.'' \126\ Similarly, ``weather''
meant ``[t]he state of the atmosphere at a given time and place,
described by temperature, moisture, wind velocity, and pressure.''
\127\ Both terms must also be read together in context, including by
reference to the other terms enumerated in the list.\128\ Each of the
other terms in
[[Page 7715]]
the definition refers to things and mechanisms of action that occur in
a particular place or under regionally bounded conditions. The terms
Congress used to define ``welfare'' speak to air pollution with adverse
impacts from local and regional exposure, not global climate change
concerns that require a very different and much longer causal chain.
The definition is broad enough to encompass the various air pollutants
and air pollution of concern, each of which interacts differently with
the environment--smog, particulate matter, and the like. Congress
understood that air pollution challenges varied from State-to-State and
region to region, while, at the same time, recognizing that the most
acute challenges--smog in highly populated urban areas, for example--
had similarities that would benefit from national standards.\129\ But
none of the many terms listed in the definition of welfare would have
been understood, absent modifying terms, to refer to global
considerations. Nor has Congress added terms like ``global'' or
``change'' that would have expanded the scope of the effects on welfare
encompassed within the definition.\130\
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\126\ Climate, Am. Heritage Dictionary 136 (1970); see, e.g.,
Alameda Cons. Ass'n v. California, 437 F.2d 1087, 1096 (9th Cir.
1971) (using ``climate'' to discuss local environmental conditions
in San Francisco Bay); Levenson's Case, 194 N.E.2d 103, 105 (Mass.
1963) (using ``climate'' to address whether moving to another state
with a different climate is a covered medical expense).
\127\ Weather, Am. Heritage Dictionary 785 (1970).
\128\ See Fischer v. United States, 603 U.S. 480, 487 (2024)
(``[T]he canon of noscitur a sociis teaches that a word is `given
more precise content by the neighboring words with which it is
associated.' That `avoid[s] ascribing to one word a meaning so broad
that it is inconsistent with' `the company it keeps' '' (citations
omitted)); Gustafson v. Alloyd Co., 513 U.S. 561, 575 (1995)
(applying canon to interpret the broad term ``communication,'' as
used in a statutory definition of ``prospectus,'' to mean only
public-facing communications that offer securities).
\129\ See, e.g., S. Rep. 91-1196, at 1-8, 24 (1970) (discussing
need for and intent of Senate bill that would eventually form much
of the 1970 CAA by reference to urban pollution problems and areas
in proximity to stationary and mobile sources and recognizing that
``protection of the public health and welfare requires definitive
knowledge of the causal relationships between exposure to air
pollution agents . . . under varying environmental conditions'');
H.R. Rep. 91-1146, at 6 (1970) (similar for House bill that informed
aspects of the 1970 CAA).
\130\ As discussed further in this section of the preamble and
the Response to Comments document, Congress has used such language
to specify the relevance of global climate change concerns in more
recent amendments to different programs. CAA section
211(o)(2)(B)(ii), for example, provides that the EPA must consider
the impact of the production and use of renewable fuels on ``climate
change'' when setting renewable fuel volumes under the RFS program.
42 U.S.C. 7545(o)(2)(B)(ii) (emphasis added); see id. 7545(o)(1)
(defining various renewable fuels in part by reference to GHG
emissions).
---------------------------------------------------------------------------
The Endangerment Finding largely avoided addressing these
interpretive problems by severing the question whether GHG emissions
from new motor vehicle engines contribute to GHG concentrations in the
atmosphere from the question whether GHG concentrations in the
atmosphere endanger public health and welfare. As discussed in further
detail below, there is no basis in the statute for severing the inquiry
in that way. Nevertheless, even with respect to endangerment and
contribution in isolation, global climate change concerns involve
causal relationships that are too uncertain, conjectural, remote, and
convoluted by intervening and confounding factors to fit within the
terms ``cause,'' ``contribute,'' and ``reasonably be anticipated to
endanger'' as used in CAA section 202(a)(1). This understanding follows
from the position discussed above that CAA section 202(a)(1) and the
statute more generally were designed to address air pollution with
harmful impacts from local and regional exposure and that are amenable
to analysis using ordinary causation standards. In specifying that
emissions may ``cause, or contribute to'' air pollution, and that air
pollution need only ``be reasonably anticipated to endanger public
health or welfare,'' Congress signaled that regulation may be
appropriate when harm is not yet occurring or is not certain to occur.
But that language bearing on the degree of certainty required does not
override ordinary background principles governing the limits of an
attenuated causal chain.
Ultimately, the Endangerment Finding did not reflect consideration
of the interpretive principles or ordinary meaning of the relevant
terms discussed above. With respect to ``air pollution,'' the
Administrator in 2009 asserted an unlimited discretion to decide what
the EPA may target through regulation by defining ``air pollution''
without reference to the best reading of the statutory term. 74 FR
66516-17. Neither the factors used to select the six GHGs--that they
are (a) ``directly-emitted,'' (b) ``long-lived,'' and (c) ``well-
mixed''--nor the reasons used to support this definition--that they (1)
``share common properties,'' (2) are ``estimated to be the primary
cause of human-induced climate change,'' (3) are ``the common focus of
climate change science research and policy analyses,'' (4) have not
been ``assessed on an individual gas approach,'' and (5) that the
Agency had combined certain pollutants in the past--are rooted in the
ordinary meaning of ``air pollution'' or any other statutory term in
CAA section 202(a)(1). Id. Instead, the Administrator extended
discussion in Massachusetts of the CAA section 302(g) definition of
``air pollutant'' to the undefined term ``air pollution,'' reasoning
that because the EPA could group multiple air pollutants into a
``combination of such agents,'' there was no relevant statutory limit
to the Agency's discretion to identify subjects for regulation. 74 FR
66537. Nor did the Administrator in 2009 grapple with the ordinary
meaning of the terms used in the CAA section 302(h) definition of
welfare, including ``climate,'' consider the full range of evidence
bearing on the ordinary meaning of ``reasonably be anticipated to
endanger,'' or appropriately evaluate the full context and structure
relevant to CAA section 202(a)(1). In short, we now conclude that the
legal analysis conducted in the Endangerment Finding, as well the
resulting interpretation, cannot be squared with the longstanding
principles that now trump deference to agency statutory interpretation
under Loper Bright.
In finalizing a different interpretation, we note that a limiting
construction is necessary to avoid absurd results and potential
conflict with the nondelegation doctrine. Because Congress cannot
delegate legislative powers to the Executive Branch, statutes granting
an agency regulatory authority must provide an intelligible principle
to guide its exercise.\131\ Our authority under CAA section 202(a)(1)
to ``prescribe . . . standards'' for emissions by any class or classes
of new motor vehicles and engines is limited by the requirement that
the Administrator find such emissions cause or contribute to air
pollution that may reasonably be anticipated to endanger public health
and welfare. The best reading of the statute recognized in this final
action circumscribes this authority to air pollution that itself
endangers health or welfare through local or regional exposure. Under
the interpretation adopted in the Endangerment Finding, however, our
authority under CAA section 202(a)(1) would have no readily discernible
limiting principle, particularly in combination with the authority
asserted to sever the analysis of endangerment and causation or
contribution. Any ``air pollutant'' emitted by new motor vehicles or
engines at more than de minimis volumes would trigger our authority and
obligation to prescribe standards so long as emissions from any and all
sources globally contributes to ``air pollution'' that, in turn, can be
said to have any causal relationship to adverse impacts on public
health and welfare, broadly defined.\132\ Put another way, the
[[Page 7716]]
Administrator in 2009 asserted authority to define the relevant ``air
pollution'' without reference to any statutory limiting principle,
leaving the EPA free to redefine the objectives of the regulatory
scheme.
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\131\ See, e.g., Gundy v. United States, 588 U.S. 128 (2019).
\132\ The consequences of this interpretation are not limited to
mobile sources. When issuing the Endangerment Finding, the EPA
understood that stationary sources would be subject to a variety of
PSD and Title V permitting obligations related to GHG emissions.
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That limitless construction of CAA section 202(a)(1) cannot be
reconciled with the Supreme Court's instructions regarding the scope of
agency authority in Loper Bright. Statutes have a single, best meaning
that may include ``a degree of discretion.'' 603 U.S. at 369. But that
discretion does not extend to redefining statutory terms in a manner
inconsistent with ordinary meaning. Although ``Congress has often
enacted'' statutes that ```expressly delegate[]' to an agency the
authority to give meaning to a particular statutory term,'' Loper
Bright, 603 U.S. at 394-95 (quoting Batterton v. Francis, 432 U.S. 416,
425 (1977)), there is no such express delegation in CAA section
202.\133\ Nor can extending CAA section 202(a)(1) to the regulation of
GHGs in response to global climate change concerns plausibly be
understood as ```fill[ing] up the details' of a statutory scheme.'' Id.
(quoting Wayman v. Southard, 23 U.S. (10 Wheat.) 1, 43 (1825)). And
``air pollution'' is not a discretion-conferring ``term or phrase that
`leaves agencies with flexibility, such as `appropriate' or
`reasonable.''' Id. (quoting Michigan, 576 U.S. at 752). Under these
circumstances the ordinary meaning of ``air pollution'' controls. The
EPA has a degree of discretion in identifying and regulating emissions
that cause or contribute to air pollution that may reasonably be
anticipated to endanger public health or welfare. But that discretion
does not extend to redefining ``air pollution'' from the local and
regional exposure problems understood at the time of enactment and
addressed throughout the statute to global climate change
concerns.\134\
---------------------------------------------------------------------------
\133\ See, e.g., Batterton, 432 U.S. at 417 n.2 (interpreting
statutory phrase ``by reason of the unemployment (as determined in
accordance with standards prescribed by the Secretary)''); 42 U.S.C.
7410(m) (authorizing the application of sanctions under certain
conditions ``in relation to any plan or plan item (as that term is
defined by the Administrator)'') (emphasis added), 7411(i)
(excluding from certain stationary source regulations ``country
elevators (as defined by the Administrator)'') (emphasis added); 33
U.S.C. 1311(b)(1)(A) (requiring application of ``the best
practicable control technology currently available as defined by the
Administrator'') (emphasis added).
\134\ In reaching this conclusion, we are mindful that the Sixth
Circuit recently applied Loper Bright to hold that the FCC exceeded
its statutory authority in a 2024 order that subjected broadband
internet service providers to ``net-neutrality principles.'' Ohio
Telecom Ass'n, 124 F.4th at 997. With respect to mobile broadband,
the FCC had interpreted ``the public switched network'' to include
not only the traditional telephone numbers comprising the network at
the time the statute was enacted, but also public internet protocol
(``IP'') addresses. Id. at 1011. The court rejected this approach,
holding as a matter of statutory interpretation that ``delegation is
not unfettered'' and that ``nothing in the statute . . . permits the
FCC to effectively change the statute's original meaning of `the
public switched network' . . . by adding `public IP addresses' to
adapt to new technology.'' Id. at 1012 (citing Loper Bright, 603
U.S. at 395).
---------------------------------------------------------------------------
Indeed, the Endangerment Finding did not even limit the definitions
selected for ``air pollutant'' or ``air pollution'' to gases emitted by
new motor vehicles or engines. Rather, the Administrator defined the
terms to include any ``climate forcer'' that met the identified
criteria and expressly reserved the right to add to the six ``well-
mixed'' GHGs in future actions. 74 FR 66520-21. Nor were the identified
criteria--that GHGs are long-lived, directly emitted, and well-mixed--
tied to any statutory language that requires the EPA to retain them or
prevents the Agency from further expanding the category. Instead, the
Administrator asserted ``broad discretion to determine appropriate
combinations of compounds that should be treated as a single air
pollutant.'' 74 FR 66537. In other words, under this interpretation of
CAA section 202(a)(1), the only limit on our authority to regulate in
response to global climate change is the exercise of reasonable
discretion.\135\ The best reading of the statute, and the reading we
restore in this final action, avoids this concern by giving the terms
Congress selected their full and ordinary meaning.\136\
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\135\ See Whitman v. Am. Trucking Ass'ns, 531 U.S. 457, 474
(2001) (``The idea that an agency can cure an unconstitutionally
standardless delegation of power by declining to exercise some of
that power seems to us internally contradictory. The very choice of
which portion of the power to exercise--that is to say, the
prescription of the standard that Congress had omitted--would itself
be an exercise of the forbidden legislative authority.'').
\136\ See Feliciano v. DOT, 605 U.S. 38, 55 n.6 (2025)
(recognizing that ``considerations of constitutional avoidance might
counsel in favor of a narrowing construction of certain laws'');
Crowell v. Benson, 285 U.S. 22, 62 (1932) (summarizing
constitutional avoidance principles); Hignell-Start v. City of New
Orleans, 154 F.4th 353, 360 (5th Cir. 2025) (accepting city's
interpretation of an ordinance that avoided constitutional
problems).
---------------------------------------------------------------------------
Under the logic of the Endangerment Finding, water vapor
(H2O) emissions from vehicles and engines could meet the
standard for regulation because the presence of additional water from
all human activities around the world can be said to contribute to
water-based disasters. See 74 FR 66520. The EPA would have the
authority, and statutory duty, to prescribe standards for water vapor
that would then trigger various permitting obligations--indeed, water
is a recognized GHG, albeit one the EPA declined to regulate on a
discretionary basis in 2009. Nor does this logic recognize any
statutory limits to regulating pollutants under the global climate
change concerns reading of CAA section 202(a)(1) that are addressed
more specifically by other provisions of the statute, including black
carbon (a form of the criteria pollutant PM), ground-level ozone
(formed by the criteria pollutant NOx), and ozone-depleting
substances (including those specifically addressed by Title VI and the
Montreal Protocol). The Administrator declined to include these matters
in the six ``well-mixed'' GHGs encompassed within the Endangerment
Finding but remained open to future actions treating them as a climate
issue. Because that reading effectively converts CAA section 202(a)(1)
into a roaming license to ``prescribe . . . standards,'' the reading
finalized in this action is more faithful to the governing principles
of statutory interpretation.
The EPA is also finalizing that the futility of GHG emission
standards in addressing the adverse health and welfare impacts
predicted in the Endangerment Finding support this interpretation of
CAA section 202(a)(1). At proposal, we sought comment on whether the
EPA must consider the potential impact of regulation when applying CAA
section 202(a)(1) and, if so, how this interpretation should inform any
final action. We received significant comments on the efficacy of the
EPA's GHG emission standards to date, particularly with respect to
their limited impact on projected trends in GMST and GSLR and the
relevance of the impacts of regulation on the interpretation of CAA
section 202(a)(1). As discussed further in section V.C of this
preamble, we conclude that even the complete elimination of GHG
emissions from all new and existing LD, MD, and HD vehicles would have
a de minimis impact on these values as a proxy for adverse health and
welfare impacts. When accounting for the emissions reduction potential
of GHG emission standards and their application only to new vehicles
and engines, the de minimis nature of these impacts becomes even
clearer. The trivial impacts of eliminating GHG emissions on trends in
GMST and GSLR--which are less than one percent of the projected changes
through 2050 and 2100 once the nature of the GHG emission standards are
taken into account--are squarely in line with regulatory and judicial
precedents treating values of approximately one percent or more as de
minimis.
Courts have long recognized the ``background'' legal principle
``against
[[Page 7717]]
which all enactments are adopted'' that general language does not
encompass de minimis concerns. Wis. Dep't of Rev. v. William Wrigley
Jr., Co., 505 U.S. 214, 231 (1992); see UARG, 573 U.S. at 309 n.1.
Unless the statute provides otherwise, agencies have implied authority
to exempt de minimis concerns ``when the burdens of regulation yield a
gain of trivial or no value.'' Ala. Power Co. v. Costle, 636 F.2d 323,
360-61 (D.C. Cir. 1979). This conclusion informs our interpretation of
CAA section 202(a)(1) by suggesting that the provision does not
encompass the attenuated chain of causation required to invoke the
authority to regulate GHG emissions where regulations cannot have more
than a trivial impact on the identified dangers to health and welfare.
Nothing in the statutory language suggests that Congress intended to
overcome this background principle, and the both the Supreme Court and
the D.C. Circuit have recognized its applicability in comparable
environmental contexts.\137\ Put another way, the inability of new
motor vehicle and engine GHG emission standards to have any material
impact on the global climate change concerns relied upon by the Agency
in the 2009 Endangerment Finding suggests that it is unreasonable to
conclude 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. For further discussion, see section
V.C of this preamble and the Response to Comments document.
---------------------------------------------------------------------------
\137\ See UARG, 573 U.S. at 309 n.1; Ala. Power, 636 F.2d at
360-61; see also EPA v. EME Homer City Generation, L.P., 572 U.S.
489 (2014) (approving of approach that did not require additional
emissions reductions from States that contributed trivially to
nonattainment in other States); Ohio v. EPA, 997 F.2d 1520, 1534-35
(D.C. Cir. 1993) (accepting de minimis approach to CERCLA five-year
risk reviews because the statute did not clearly prohibit the
approach and anything less would be contrary to legislative design).
---------------------------------------------------------------------------
Finalizing this interpretation effectively returns the EPA to its
longstanding practice prior to 2009 of applying CAA section 202(a)(1)
and related statutory endangerment provisions to air pollution that
adversely impacts public health and welfare through local or regional
exposure. As discussed further in sections III.A and V.B of this
preamble, we historically utilized this authority on a relatively
infrequent basis to prescribe standards for pollutants identified in
the CAA itself, including NOX, PM, HCs and other VOCs, and
CO, and then only as a backstop when more specific CAA section 202
authorities were unavailable. The distinction between air pollution
that harms public health and welfare through local and regional
exposure and global ``air pollution'' consisting of GHG concentrations
without any such direct impacts also played a role in our evaluation of
waiver requests under CAA section 209.\138\ Even in the Endangerment
Finding, the Administrator recognized that ``[n]one'' of the identified
health impacts were ``associated with direct exposure'' and that we had
previously applied CAA section 202(a)(1) to the ``more typical local or
regional air pollution problem.'' 74 FR 66527, 66538 (emphases added);
see 74 FR 66531 (explaining that the Agency considered the same causal
``pathways'' in assessing public health and welfare impacts). In
adopting a novel analytical approach in the Endangerment Finding, we
failed to adequately address this prior practice and improperly relied
on the Supreme Court's decision in Massachusetts for the proposition
that CAA section 202(a)(1) authorizes emission standards in response to
air pollution raising global climate change concerns. As discussed
below, Massachusetts did not separately construe the scope of the EPA's
authority to regulate under CAA section 202(a)(1), and the Court has
since made clear in UARG and West Virginia that our authority to
regulate an ``air pollutant'' encompassed within the Act-wide
definition must be evaluated in the context of the particular statutory
provision that confers authority to regulate.
---------------------------------------------------------------------------
\138\ See, e.g., ``California State Motor Vehicle Pollution
Control Standards; Notice of Decision Denying a Waiver of Clean Air
Act Preemption for California's 2009 and Subsequent Model Year
Greenhouse Gas Emission Standards for New Motor Vehicles,'' 73 FR
12156, 12161 (Mar. 6, 2008) (denying California's waiver request for
GHG emission standards on the ground that ``the different, and
global, nature of the pollution at issue'' requires a different
conceptual approach); see also ``The Safer Affordable Fuel-Efficient
(SAFE) Vehicles Rule Part One: One National Program,'' 84 FR 51310,
51328-52 (Sept. 27, 2019) (summarizing and applying this
interpretation).
---------------------------------------------------------------------------
In Massachusetts, the Supreme Court rejected the argument that GHGs
are not ``air pollutants'' under the Act-wide definition, reasoning
that CAA section 302(g)'s use of the word ``any'' in connection with
``air pollutant agent or combination of such agents, including any
physical [or] chemical . . . substance'' was sufficiently broad to
encapsulate the combination of GHGs at issue. 549 U.S. at 530. On this
basis, the Court stated that the EPA ``has the statutory authority to
regulate the emission of such gases from new motor vehicles.'' Id. at
532. The Court did not, however, separately decide whether including
GHGs within the definition of ``air pollutant'' meant that we must find
that GHGs meet the statutory standard for regulation under CAA section
202(a) because they cause or contribute to air pollution which
endangers the public health or welfare. Rather, the Court emphasized
that its review of the denial of the rulemaking petition was
``extremely limited'' and concluded its opinion by clarifying that it
``need not and do[es] not reach the question whether on remand EPA must
make an endangerment finding.'' Id. at 527, 534.
Consistent with Massachusetts, and reading that decision in harmony
with UARG, we interpret the CAA as setting out a broad, threshold
definition of ``air pollutant'' on an Act-wide basis that must be
interpreted in the context of each applicable, particular provision
granting regulatory authority in order to determine whether that
provision authorizes the EPA to regulate an air pollutant under that
particular authority. For purposes of CAA section 202(a)(1), that means
that even if GHGs are ``air pollutant[s]'' as defined on an Act-wide
basis, they must meet the statutory standard for regulating emissions
from new motor vehicles and engines before we may invoke our regulatory
authority. Put simply, regardless whether GHGs are ``air pollutants''
as defined in CAA section 302(g), they must satisfy the same standard
as any other emitted ``air pollutant'' by causing or contributing to
``air pollution which may reasonably be anticipated to endanger public
health or welfare.''
This understanding is necessary to account for UARG, in which the
Supreme Court distinguished between ``the Act-wide definition'' of air
pollutant and the application of that definition to the Act's
regulatory provisions. 573 U.S. at 320. The Court specifically
addressed the holding in Massachusetts, adopting the argument that
``while Massachusetts rejected EPA's categorical contention that [GHGs]
could not be air pollutants for any purposes of the Act, it did not
embrace EPA's [then] current, equally categorical position that [GHGs]
must be air pollutants for all purposes regardless of the statutory
context.'' Id. (cleaned up).
In sum, CAA section 202(a)(1) does not provide authority to
regulate GHGs based on global climate change concerns because that
provision authorizes regulating only emissions that ``cause, or
contribute to, air pollution which may reasonably be anticipated to
endanger public health or welfare.'' The EPA must ``ground its reasons
for action or inaction in the statute,'' Massachusetts, 549 U.S. at
535, and
[[Page 7718]]
``possess[es] only the authority that Congress has provided,'' NFIB v.
DOL, 595 U.S. 109, 117 (2022). In finalizing this interpretation, we
note that our actions must be consistent with ``the single, best
meaning'' of the statute, `` `fixed at the time of enactment''' and
resolved through application of ``all relevant interpretive tools,''
and cannot expand our authority in response to pressing concerns based
on statutory silence or ambiguity. Loper Bright, 603 U.S. at 400, 411
(quoting Wis. Cent., 585 U.S. at 284). Properly interpreted, the
statute confers ``regulatory flexibility'' to respond to ``changing
circumstances and scientific developments,'' Massachusetts, 549 U.S. at
532, while bounding the scope of the EPA's authority to ``air
pollution'' as that term was understood at the time of enactment.
Findings and Standards. The EPA is also finalizing as proposed that
CAA section 202(a)(1) requires issuing emission standards together with
the findings necessary to invoke our regulatory authority, rather than
severing the regulatory action into separate endangerment and
standards-setting proceedings. The statute begins by providing that the
Administrator ``shall prescribe . . . standards applicable to the
emission of any air pollutant from any class or classes of new motor
vehicles or new motor vehicle engines,'' and follows this requirement
by describing the scope of the duty to regulate air pollutant emissions
``which, in his judgment cause, or contribute to, air pollution which
may reasonably be anticipated to endanger public health or welfare.''
The best reading of the statute requires the Administrator, when
prescribing any emission standard for new motor vehicles or engines, to
find that the air pollutant or air pollutants emitted by the class or
classes of new motor vehicles or engines subject to the standard cause
or contribute to air pollution that may reasonably be anticipated to
endanger public health or welfare.
The Endangerment Finding severed this statutory language by finding
endangerment and contribution in the abstract for all potential CAA
section 202 sources with respect to GHGs. In so doing, the
Administrator vastly increased the Agency's authority by removing the
restrictions Congress placed on the issuance of emission standards. As
a result of this new conception of authority, the EPA may issue a
single endangerment finding in the abstract with respect to emissions
from all sources potentially subject to CAA section 202 (and their
existing-source counterparts) without addressing the danger posed by
any particular source category or the causal role of that particular
source category in any identified danger. The EPA relied on the
Endangerment Finding to prescribe emission standards for various
classes of new motor vehicles and engines, as well as a variety of
other sources under distinct statutory authorities, without making the
requisite findings or assessment of factors necessary to regulate the
sources in question.\139\ Congress enacted CAA section 202(a)(1) as an
integrated regulatory provision for a reason, and giving effect to the
language of the statute requires the issuance of emission standards
only when the Administrator has made an integrated finding of both
endangerment and cause or contribution. Put another way, it is
impermissible for the Administrator to make findings that trigger a
duty to regulate without prescribing the emission standards required in
response to such a finding, just as the Administrator may not prescribe
emission standards without making the findings required by the statute.
---------------------------------------------------------------------------
\139\ See sections III.D and VII of this preamble for a summary
of the EPA's rulemaking activities in response to the Endangerment
Finding.
---------------------------------------------------------------------------
This interpretation is consistent with the EPA's implementation of
CAA section 202(a)(1) and similar provisions of the CAA prior to 2009.
In the Endangerment Finding, the Administrator acknowledged that
``typically endangerment and cause or contribute findings have been
proposed concurrently with proposed standards under various sections of
the CAA, including CAA section 201(a).'' 74 FR 66501. That has also
been our approach to other similarly worded provisions in the statute,
including in response to petitions seeking findings and action under
CAA section 115.\140\ We believe that our historical practice under CAA
section 202(a)(1) reflects the better reading of the statute and is
entitled to greater weight. As the Supreme Court explained in Loper
Bright, such weight is ``especially warranted when an Executive Branch
interpretation was issued roughly contemporaneously with enactment of
the statute and remained consistent over time.'' 603 U.S. at 386.
---------------------------------------------------------------------------
\140\ 42 U.S.C. 7415(a); see Her Majesty the Queen v. EPA, 912
F.2d 1525, 1533-34 (D.C. Cir. 1990) (deferring to the EPA's
interpretation of CAA section 115(a) as requiring an integrated
action because the statute's text and structure ``creates a specific
linkage between the endangerment finding and the remedial
procedures'').
---------------------------------------------------------------------------
In departing from the EPA's historical practice in the Endangerment
Finding, the Administrator reasoned that ``[t]he text of CAA section
202(a) is silent on this issue'' and ``invoked the procedural
discretion that is provided by CAA section 202(a)'s lack of specific
direction.'' 74 FR 66501. We no longer maintain that CAA section
202(a)(1) is silent on the issue, as the statute sets out an integrated
process that requires the EPA to prescribe standards when the
Administrator finds certain conditions are met. When Congress intends a
multi-step inquiry in the environmental context, it typically says so
expressly. In the NAAQS program, for example, the CAA separates our
authority to establish air quality criteria under CAA section 108 from
our obligation to promulgate and revise NAAQS based on the criteria
under CAA section 109, in addition to separating both of these
regulatory steps from our duties to implement the NAAQS by reviewing
State Implementation Plans (SIPs) or promulgating Federal
Implementation Plans (FIPs) under CAA section 110 and related statutory
provisions.\141\ A particularly relevant analogy is Clean Water Act
section 303(c)(4), which pairs the Administrator's authority to
``determin[e] that a revised or new [water quality standard] is
necessary to meet the requirements of this chapter'' with the
requirement that the Administrator ``shall promptly prepare and publish
proposed regulations'' after making such a determination and
``promulgate any revised or new standard . . . not later than ninety
days after he publishes such proposed standards.'' \142\ Even if CAA
section 202(a)(1) were ambiguous or silent in this respect, agencies
may no longer assert delegated discretionary authority when the statute
is amenable to a single, best reading under ordinary tools of statutory
interpretation. As the Supreme Court held in Loper Bright, ``statutory
ambiguity . . . is not a reliable indicator of actual delegation of
discretionary authority to agencies.'' 603 U.S. at 411.
---------------------------------------------------------------------------
\141\ See 42 U.S.C. 7408, 7409, 7410.
\142\ 33 U.S.C. 1313(c)(4), (c)(4)(B). Various provisions of the
SDWA and the Toxic Substances Control Act (TSCA) similarly
articulate multi-step processes for determining risk and addressing
risk through regulation using language that Congress did not include
in CAA section 202. See, e.g., NRDC, 67 F.4th at 398-402 (discussing
the two-step process for promulgating national primary drinking
water regulations under SDWA section 1412).
---------------------------------------------------------------------------
Severing the EPA's standards-setting authority from the findings
that trigger a duty to exercise that authority shaped the analysis in
the Endangerment Finding in a manner that ran counter to the statute.
The Endangerment Finding first projected adverse public health and
welfare impacts of global climate change and attributed those adverse
impacts to
[[Page 7719]]
all manmade sources of GHG emission around the world and then,
separately, used data from existing CAA section 202(a) sources in the
United States to find that new motor vehicles and engines in the United
States contributed to global GHG air pollution. The Administrator
treated adaptation (adjustments to the effect of climate change that
lessen impacts) and mitigation (reductions in emissions and global GHG
concentrations unrelated to CAA section 202(a)(1) regulation) as
outside the scope. 74 FR 66512. Moreover, the Administrator declined to
consider cost, asserting that the Endangerment Finding imposed no
regulatory requirements as a standalone action and relying on the
Supreme Court's decision in Whitman v. American Trucking Associations,
531 U.S. 457 (2001), that the EPA cannot consider cost in setting the
NAAQS under CAA section 109(b)(1). 74 FR 66515. Nor did the
Administrator consider potential beneficial impacts from climate change
with respect to whether and which standards would be appropriate. See
74 FR 66524 (purporting to compare ``risks and benefits'' only with
respect to endangerment).
Severance also shaped all subsequent standards prescribed and
revised in reliance on the Endangerment Finding in a manner we now
conclude was unlawful. The EPA asserted in subsequent rulemakings that
there was no need to make particularized findings for the relevant
source category because the Endangerment Finding identified public
health and welfare dangers and contribution for all CAA section 202
source categories. Nor did we consider the impacts of adaptation or
mitigation when prescribing standards--considerations that the
Endangerment Finding also treated as out of scope. As a result, the
decision to sever meant that the EPA has never meaningfully considered
or invited public comments on the cost, effectiveness, and continued
propriety of its GHG regulatory program.
These considerations should have been taken into account when the
EPA triggered a duty to regulate in the Endangerment Finding by
invoking our CAA section 202(a)(1) authority. CAA section 202(a)(2)
expressly provides that ``[a]ny regulation prescribed under paragraph
(1) of this subsection . . . shall'' provide adequate time for ``the
development and application of the requisite technology, giving
appropriate consideration to the cost of compliance within such
period.'' \143\ CAA section 202(a)(1) authorizes the Administrator to
``by regulation prescribe'' standards ``in accordance with the
provisions of this section'' and does not separately authorize
standalone findings, meaning any action taken ``under paragraph (1) of
this subsection'' is subject to the considerations in paragraph (2). In
addition, the Supreme Court explained in Michigan that ``agency action
is lawful only if it rests `on a consideration of the relevant
factors,' '' 576 U.S. at 750 (quoting State Farm, 463 U.S. at 43),
including ``at least some attention to cost,'' id. at 752.
---------------------------------------------------------------------------
\143\ 42 U.S.C. 7521(a)(2).
---------------------------------------------------------------------------
Accordingly, we now conclude that the Administrator erred in
analogizing the NAAQS program and the Supreme Court's decision in
Whitman to avoid considering costs in the Endangerment Finding. Unlike
CAA section 202(a)(1), the language in CAA section 109(b)(1) makes no
reference to cost or implementation and focuses solely on the
protection of public health. Nor does CAA section 109(b) include the
lead time and technical feasibility concepts embedded in CAA section
202(a). And whereas CAA section 202(a)(1) sets out an integrated
authority to prescribe emission standards when the provision's
triggering condition is satisfied, CAA section 109(b)(1) uses mandatory
language requiring the EPA to establish certain standards, the content
and implementation of which are specified in various provisions
throughout Title I of the Act. We further note that the Supreme Court's
decision in Massachusetts did not address the question whether the EPA
could issue standalone findings or bar the Administrator from taking
cost and implementation concerns into account when exercising CAA
section 202(a) authority. Rather, Massachusetts must be read together
with Michigan, and the language of CAA section 202(a)(1) must be read
in context to ``produc[e] a substantive effect that is compatible with
the rest of the law.'' UARG, 573 U.S. at 321 (quoting United Sav. Ass'n
of Tex. v. Timbers of Inwood Forest Assocs., 484 U.S. 365, 371 (1988)).
Endangerment and Cause or Contribute. The EPA is also finalizing as
proposed that CAA section 202(a)(1) requires the Agency to evaluate
whether source emissions cause or contribute to air pollution and
whether that air pollution poses endangerment in a single causal chain,
rather than considering these issues in isolation by severing the
inquiries. The relevant inquiry is whether ``the emission of any air
pollutant from any class or classes of new motor vehicles or new motor
vehicle engines,'' in the judgment of the Administrator, ``cause, or
contribute to, air pollution which may reasonably be anticipated to
endanger public health or welfare.'' As explained in this section, the
emission must cause or contribute to the danger posed by the air
pollution to a sufficient extent to satisfy the standard for
regulation.
In the Endangerment Finding, the Administrator made two distinct
findings based on two distinct sets of assumptions. In the first, the
Administrator found that the ``air pollution,'' defined as the combined
global concentrations in the upper atmosphere of six ``well-mixed
GHGs,'' CO2, methane, N2O, HFCs, PFCs, and
SF6, endangered public health or welfare by playing a causal
role in global temperature increases, sea level rise, and other
phenomena (including ocean pH changes), which, in turn, were then
asserted to play a causal role in environmental phenomena with adverse
impacts on public health and welfare. 74 FR 66516. In the second, the
Administrator found that the quantity of the ``air pollutant'' (defined
as the combination of same six ``well-mixed GHGs'') emitted by new
motor vehicles and engines annually contributed to the ``air
pollution.'' 74 FR 66536. The Administrator did not consider the extent
to which emissions from CAA section 202(a)(1) sources have a more than
de minimis effect on the danger identified with respect to elevated
concentrations of GHGs in the upper atmosphere--let alone whether
emissions from any particular class or classes of sources that the EPA
intended to regulate had such an effect. Nor did the Administrator
recognize the mismatch between ``air pollution'' consisting of global
concentrations formed by GHG emissions past, present, and future and
``air pollutant'' emissions from new motor vehicles and engines on an
annual basis, or the problems associated with measuring domestic
contribution against an air pollution problem that necessarily requires
global emissions to result in the identified danger.
Upon review, we no longer believe that the approach taken in the
Endangerment Finding was consistent with the language of CAA section
202(a)(1) and the structure of the CAA, which requires making distinct
findings for regulating distinct types of emission sources and
authorizing different regulatory tools when such standards are met. For
example, CAA section 111(b)(1)(A) authorizes the EPA to regulate
emissions from listed categories of stationary sources if the
Administrator determines those sources emit air pollutants that
``significantly contribute'' to air pollution that
[[Page 7720]]
endangers public health or welfare.\144\ When that standard is met, CAA
section 111(b)(1)(B) requires the EPA to regulate such emissions from
such sources by setting standards of performance that, among other
things, reflect the best system of emission reduction that has been
adequately demonstrated in practice.\145\ The CAA similarly sets out
distinct standards for regulating and distinct modes of regulation for
additional major source categories, including vehicles in use, aircraft
engines, and separately addresses when and how to respond to
international emissions that impact the United States. The Endangerment
Finding effectively attributed the total GHG emissions coming from all
of these various distinct sources within the United States, as well as
from all international sources, to the mobile sources regulated under
CAA section 202 without having made the requisite determinations for
any of those sources and without considering the different regulatory
tools Congress authorized for those sources as compared to CAA section
202(a) sources. Although the statute anticipates that ``air pollution''
may reflect contributions from multiple source categories, application
of the global climate change concerns reading of CAA section 202(a)(1)
leads to impermissible gaps between the contribution and endangerment
analyses that the Endangerment Finding failed to address.
---------------------------------------------------------------------------
\144\ 42 U.S.C. 7411(b)(1)(A).
\145\ 42 U.S.C. 7411(a)(1), (b)(1)(B). CAA section 111 also
differentiates between new and existing stationary sources in a
listed source category and limits the EPA's role with respect to
existing sources by authorizing only emission guidelines implemented
by the States. See id. 7411(d).
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Whereas the identified ``air pollution'' leads to endangerment
because of the sum total of all emissions, past, current, and
projected, from all source categories foreign and domestic, the
identified contribution of ``air pollutant emissions'' from new motor
vehicles and engines was measured in annual terms. In other words, the
Endangerment Finding compared the wrong figures in tying contribution
to endangerment. The Administrator found contribution based on the
conclusion that existing vehicles and engines constituted 4.3 percent
of annual global GHG emissions. But the Administrator found
endangerment based on the theory that ``air pollution'' consisting of
total global concentrations of the six ``well-mixed'' GHGs endangered
public health and welfare. This mismatch is not presented when
analyzing the air pollution addressed expressly by the CAA because the
mechanism of harm does not depend on centuries-long time horizons.
Annual emissions of airborne lead, for example, are readily measurable
against the total annual concentrations of airborne lead in areas of
concern, and the health and welfare impacts of air pollution in the
form of airborne lead can be analyzed on the same scale. By completely
severing the contribution and endangerment analyses for the six ``well-
mixed'' GHGs, the Endangerment Finding avoided grappling with this
disconnect. The difficulties in analyzing the nexus between
contribution and endangerment was not a problem to be avoided, but a
further reason to conclude that CAA section 202(a)(1) was not designed
to address global climate change concerns.
The Administrator also defined the relevant ``air pollution'' as
the combined global concentration of six ``well-mixed GHGs'' but found
that CAA section 202(a) sources emitted only four of them:
CO2, methane, NOX, and HFCs. 74 FR 66538. As a
result, the ``air pollution'' identified as endangering public health
or welfare included PFCs and SF6, and the ``air pollution''
used to conclude that CAA section 202(a) sources satisfy the regulatory
standard did not. Contrary to the EPA's conclusion at the time, 74 FR
66541, that difference is material, as PFCs and SF6 are
asserted to have many times the global warming potential of
CO2.\146\ Severing the endangerment and cause-or-contribute
analysis allowed the Agency to compare apples and oranges in a manner
inconsistent with the best reading of the statute.
---------------------------------------------------------------------------
\146\ U.S. Environmental Protection Agency. (Last updated Jan.
16, 2025). Understanding Global Warming Potentials: https://www.epa.gov/ghgemissions/understanding-global-warming-potentials.
---------------------------------------------------------------------------
The Endangerment Finding also did not limit the analysis of
contribution to ``new motor vehicles or new motor vehicle engines'' in
the United States, which are the only sources covered by the EPA's CAA
section 202(a) authority.\147\ Because the Administrator considered all
sources in analyzing the danger posed by elevated concentrations of
GHGs in the upper atmosphere, the endangerment analysis necessarily
included emissions from foreign and domestic vehicles that had been in
use for years or decades and were not ``new.'' Even when analyzing
contribution, the Administrator used emission estimates from ``the
entire fleet of motor vehicles in the United States for a certain
calendar year'' rather than projecting emissions from new motor
vehicles and engines over time. 74 FR 66543. That decision increased
the absolute contribution figure by orders of magnitude, including
because newer vehicles and engines tend to be more efficient and emit
less.\148\ Difficulties in disaggregating emission data from emission
sources, however reasonable, do not license us to read the term ``new''
out of the statutory text.
---------------------------------------------------------------------------
\147\ 42 U.S.C. 7521(a)(1) (emphases added); see, e.g., City of
New York v. Chevron Corp., 993 F.3d 81, 101 (2d Cir. 2021)
(``Together, the statute's silence on the issue of extraterritorial
reach, the fact that the Act contemplates the need for reciprocal
protections from foreign nations, and the State Department's lead
role in setting foreign policy on environmental matters, all plainly
demonstrate that the Clean Air Act regulates only domestic
emissions.'').
\148\ For additional discussion of improvements in new motor
vehicles and engines relative to older vehicles and engines, see
section VI.D of the preamble to the proposed rule.
---------------------------------------------------------------------------
We further conclude that severing the endangerment and cause or
contribution findings leads to untenable results and lacks any limiting
principle. To illustrate the problem, the same logic would allow the
EPA to issue emission standards for water vapor (H2O),
another substance emitted by new motor vehicles and engines that is
also considered a GHG. Considered in isolation, increased
H2O concentrations in the atmosphere from all human
activities can be said to endanger public health or welfare by
resulting in rain that leads to slip-and-fall injuries, drownings, and
damage to crops, livestock, and property, including through pools,
rivers, and floodwater, although water vapor is not itself harmful and
is necessary to sustain life. Also considered in isolation, CAA section
202 sources can be said to ``contribute'' to elevated H2O
concentrations in the atmosphere from all anthropogenic sources, and
these emissions of water vapor would thereby assertedly ``contribute''
to global climate effects similar to those attributed to other GHGs.
CAA section 202(a)(1) does not contemplate prescribing emission
standards for such an omnipresent, naturally occurring, and essential
component of the ambient air because the text requires a unified
analysis that ensures a nexus between the extent of contribution and
the resulting danger. The logic of regulating water vapor appears
absurd, but it is the same logic required to regulate GHGs under CAA
section 202(a)(1). And the Administrator acknowledged in the
Endangerment Finding that the statutory interpretation adopted in that
action could support adding water vapor to the defined regulatory for
``climate forcing'' GHGs.
The decision to sever the analysis of endangerment from the
analysis of contribution, combined with the decision to sever the
Administrator's
[[Page 7721]]
findings from any standards prescribed as a result, produced an
analysis that is incompatible with the statute. In the Endangerment
Finding, the Administrator concluded that anything more than a trivial
or de minimis contribution to elevated global GHG concentrations by CAA
section 202(a) sources was sufficient to trigger regulation because the
``unique, global aspects of the climate change problem tend to support
contribution at lower percentage levels of emissions than might
otherwise be considered appropriate when addressing a more typical
local or regional air pollution problem.'' 74 FR 66538. Because the
Endangerment Finding did not consider the standards that the statute
requires when the Administrator makes such a finding, we did not
consider whether emission standards for new motor vehicles would be
futile as a means to address the identified dangers of GHG emissions
from all anthropogenic sources. As discussed in section V.C of this
preamble, available modeling indicates that reducing GHG emissions from
all vehicles and engines in the United States to zero would not have a
measurable, material impact on trends in global temperature or sea
level. Because our GHG emission standards apply only to new vehicles
and engines and have not, to date, mandated the elimination of all
emissions, their impact is only a fraction of the already de minimis
impacts identified in the modelled scenario. It was foreseeable at the
time that issuing the Endangerment Finding would trigger a duty to
regulate and that stringent measures would be necessary under all of
the EPA's separate statutory authorities, and not just CAA section
202(a), to have any potentially material impact on the identified harm.
Refusing to consider these foreseeable consequences was inconsistent
with the statutory scheme and, as explained further below, an
unreasonable exercise of the authority we asserted.
Finally, the Administrator did not adequately consider the meaning
in context of the statutory term ``endanger'' and failed to identify
with sufficient rigor the purported danger linked to GHG emissions from
new motor vehicles and engines. As used in CAA section 202(a)(1),
``endanger'' is not best read as meaning any predicted negative impact
to any public health or welfare value, as that interpretation would
render the constraint placed on the EPA's authority to prescribe
standards essentially meaningless, thereby violating ordinary
principles of statutory interpretation and raising constitutional
nondelegation concerns. Severing the endangerment and contribution
inquiries improperly allowed the Administrator to avoid this concern by
concluding that new motor vehicle and engine emissions included more
than de minimis GHG emissions, even if those emissions did not
themselves contribute to a danger in any meaningful sense. See 74 FR
66543 (asserting that ``contributors must do their part even if their
contributions to the global problem, measured in terms of percentage,
are smaller than typically encountered'').
2. Summary of Comments and Updates Since Proposal
The EPA received comments from a variety of stakeholders supporting
and criticizing the legal rationale set out in the proposed rule.
Commenters supporting the rescission and repeals pointed to the Supreme
Court's decisions in West Virginia, UARG, and Loper Bright as strongly
supportive of what we proposed to be the best reading of CAA section
202(a)(1) and generally agreed that the Endangerment Finding erred in
severing the statutory analysis in various ways. Commenters opposing
the rescission and repeals generally argued that the Supreme Court's
decision in Massachusetts and several subsequent precedents must be
read as requiring the EPA to regulate GHG emissions and that the
statute must be interpreted broadly to accomplish what they described
as the preventative purposes of the statute. The final rationale set
out in the preceding section of this preamble reflects this input by
including certain interpretive evidence identified by commenters and
additional analysis developed in response to arguments raised during
the public comment period. In this subsection, we summarize major
themes presented in the comments received along with our high-level
responses. For detailed comment summaries and our full responses
thereto, please see the Response to Comments document in the docket for
this rulemaking.
Comment: Commenters supportive of the proposal generally agreed
that the EPA exceeded its statutory authority under CAA section
202(a)(1) by issuing the Endangerment Finding and resulting standards.
Some of these commenters emphasized agreement with our proposed
interpretation of the term ``air pollution'' and the role that term
plays in the provision, while others further agreed with our proposed
understanding of the nature of the statutory analysis and the ways in
which the Endangerment Finding erred in severing the analysis.
With respect to ``air pollution,'' commenters offered additional
legislative history, regulatory history, or other support for
interpreting the term as referring to pollution that adversely impacts
health or welfare through local or regional exposure, such as smog.
Several commenters recounted the air pollution concerns leading up to
the 1965, 1970, and 1977 enactments in particular and emphasized that
Congress and the public understood the problem in terms of increased
urbanization, including in cities that crossed over State lines and
made pollution control strategies by individual States and localities
difficult with respect to mobile sources. These commenters provided
further evidence in contemporary legislative history and other public
materials that Congress understood the national air pollution problem
being addressed in legislation as one related to criteria pollutants
that lead to smog, primarily in urban areas, as well as air toxics.
Several also pointed to additional provisions of the CAA, including
general statements of purpose and the structure of the statute as a
whole, to argue that Congress designed a regulatory scheme for
regulating domestic emissions and domestic impacts in a manner that
does not contemplate or authorize regulation in response to global
climate change concerns. Several commenters also cited case law to
argue that the CAA does not regulate extraterritorially. With respect
to the ways in which the Endangerment Finding severed the statutory
analysis, several commenters agreed that these considerations were
relevant to statutory interpretation and authority as well as the
quality or validity of the underlying analysis in the Endangerment
Finding.
Response: The EPA agrees with these comments and is finalizing, as
proposed, that the Endangerment Finding exceeded the Agency's statutory
authority under CAA section 202(a)(1) in multiple respects. In addition
to the further discussion incorporated into section V.A.1 of this
preamble, we agree that viewed as a whole, the legislative history and
other materials contemporary to the 1965, 1970, and 1977 enactments
most relevant to interpreting the key statutory language in CAA section
202(a)(1) tend to undermine the interpretation adopted in the
Endangerment Finding and support the interpretation we are finalizing
in this action. While legislative history cannot trump the statutory
text, widely publicized materials and evidence of common understanding
at the time of enactment can be relevant to the
[[Page 7722]]
ordinary meaning of undefined terms. Here, that material supports the
conclusion that ``air pollution'' as used in CAA section 202(a)(1)
meant pollution that harms public health or welfare through local or
regional exposure, rather than gases that are not harmful in that sense
but may contribute to global phenomena on a far more attenuated chain
of causation. We further agree that other provisions of the statute,
including the findings and declarations of purpose in CAA section 101,
support the interpretation finalized in this action by indicating that
while Congress referenced and addressed local and regional problems, it
did not reference global climate change concerns at all through the
1970s and even today uses express terms in the relatively few
provisions that address GHGs, such as in the RFS and provisions
authorizing certain grants and financial or technical assistance.
Comment: Adverse commenters argued that the EPA's proposed
interpretation of CAA section 202(a)(1) is foreclosed in whole or in
part by precedent. Many of those commenters argued that the Supreme
Court's decision in Massachusetts unambiguously held that the EPA has
authority to prescribe GHG emission standards for new motor vehicles
and engines in response to global climate change concerns. Others also
cited to subsequent cases, including the Supreme Court's decisions in
American Electric Power Co. v. Connecticut, 564 U.S. 410, 426 (2011),
UARG, and West Virginia, as well as the D.C. Circuit's decisions in
Coalition for Responsible Regulation and American Lung Association, as
individually or collectively precluding the EPA from evaluating and
applying the best reading of CAA section 202(a)(1) and related
provisions.
Response: The EPA disagrees with these comments, many of which
significantly overread relevant precedent and misunderstand principles
governing the scope of judicial decisions and statutory interpretation.
Fundamentally, commenters' arguments stem from the flawed proposition
that the Supreme Court held in Massachusetts that the EPA can or must
regulate GHG emissions from new motor vehicles and engines in response
to global climate change concerns. As detailed in section V.A.1 of this
preamble, we no longer believe that this reading is accurate on its own
terms, nor does it reflect the Court's subsequent holdings and
rationale in UARG, West Virginia, and, more generally, Michigan and
Loper Bright. The Court in Massachusetts rejected the policy reasons
the Agency offered for declining to regulate and the interpretation of
the statutory definition of ``air pollutant'' in CAA section 302(g)
that the Agency relied upon to deny petitions for rulemaking in 2003.
Contrary to the framing presented by some commenters, the Court found
that the statute ``foreclose[d]'' the Agency's reading and is
``unambiguous'' only with respect to the ``air pollutant'' definition,
holding that ``the definition embraces all airborne compounds of
whatever stripe.'' 549 U.S. at 529 (citing 42 U.S.C. 7602(g)). Nor do
commenters offer persuasive reasons to conclude that the Court's
subsequent decision in UARG, which held that the term ``air pollutant''
as defined in the statute and construed in Massachusetts must be read
in context of the regulatory provision in which it appears, applies to
the entirety of the CAA except for CAA section 202(a)(1). 573 U.S. at
318-20 (``[Massachusetts] did not hold that EPA must always regulate
[GHGs] as an `air pollutant' everywhere that term appears in the
statute, but only that EPA must `ground its reasons for action or
inaction in the statute,' rather than on `reasoning divorced from the
statutory text.' '' (quoting 549 U.S. at 532, 535)).
Similarly, we disagree with commenters' suggestions that additional
precedents since Massachusetts purported to decide the interpretive
issues addressed in this final action. In American Electric Power, for
example, the Supreme Court held that federal common law was not the
appropriate avenue for deciding ``whether and how to regulate carbon-
dioxide emissions from powerplants.'' 564 U.S. at 426. Indeed, the
Court has since confirmed in West Virginia that it ``said nothing about
the ways in which Congress intended EPA to exercise its power'' under
the CAA, particularly with respect to the regulation of stationary
sources under CAA section 111(d). 597 U.S. at 730. Commenters' attempt
to repeat similar arguments for UARG and West Virginia lack credibility
given the questions presented in those cases and the reasoning adopted
by the Court with respect to the questions presented. These comments
largely did not engage with the interpretation of ``air pollution''
presented at proposal and finalized in this action, and the relatively
small number that did failed to offer persuasive evidence that rebuts
the ordinary meaning of the term or relevant contextual or structural
indicators in the statutory text. For additional discussion of these
cases, the D.C. Circuit's decisions in Coalition for Responsible
Regulation and American Lung Association, and other issues bearing on
statutory interpretation, see the Response to Comments document.
In this final action, the EPA is acting consistently with
Massachusetts by ``ground[ing] its reasons for action or inaction in
the statute'' and concluding that, given the best reading of the
language in CAA section 202(a)(1), we lack authority to issue an
affirmative finding that triggers our regulatory authority in response
to global climate change concerns. 549 U.S. at 535.
Comment: Adverse commenters also asserted that the EPA's proposed
interpretation gave inadequate weight to the statutory terms ``public
health'' and ``welfare.'' These commenters generally argued that
Congress delegated broad authority to the EPA to regulate any air
pollutant emissions in response to any air pollution that may arise in
the future, so long as we conclude such regulation further public
health or welfare. Several of these commenters focused particularly on
the statutory definition of welfare in CAA section 302(g), and
particularly on the term ``climate,'' to argue that Congress wrote
these concepts into the statute to give the Agency such broad
authority.
Response: The EPA disagrees that the references in CAA section
202(a)(1) to ``public health'' and ``welfare'' confer discretion broad
enough to identify and regulate any form of air pollution, including in
the form of global climate change concerns. As discussed in section
V.A.1 of this preamble, that interpretation, which we acknowledge is
consistent with the interpretation adopted in the Endangerment Finding,
is inconsistent with ordinary principles of statutory interpretation
and would needlessly give rise to absurdity and nondelegation concerns
that the statute itself does not create, properly interpreted. With
respect to the statutory definition of ``welfare,'' we note that the
ordinary meaning of the term ``climate'' at the time of enactment is
nowhere near as broad as commenters suggest and that the term, as well
as additional terms in the definition such as ``weather'' and
``visibility,'' must be read in the context of a much broader list that
consists of terms having the physical property of being local or
regional. For additional discussion, see the detailed explanation of
the term ``welfare'' and additional statutory terms informed by
proximate cause principles, including ``cause,'' ``contribute,'' and
``reasonably be anticipated to endanger,'' in the Response to Comments
document.
[[Page 7723]]
B. Lack of Clear Congressional Authorization
The EPA is also finalizing as proposed that, in addition to the
basis set out above, we lack the ``clear congressional authorization''
required under the major questions doctrine to decide the Nation's
response to global climate change concerns. West Virginia, 597 U.S. at
723 (quoting UARG, 573 U.S. at 324). In this subsection, we conclude
that the major questions doctrine applies to the Endangerment Finding
because the global climate change concerns addressed in that action,
and the mandatory duty to regulate triggered by that action, present a
major question of undeniable political and economic significance. Until
2009, we had never used CAA section 202(a)(1) to assert authority over
an entirely new subject, instead hewing closely to the air pollution
problems that Congress identified in CAA section 202. To break with
this longstanding practice, we developed a ``unique'' framework that
broadened our statutory authority to prescribe emission standards in
response to air pollution far enough to encompass global climate change
concerns. The result was a new policy direction for the United States--
one that Congress had repeatedly and recently declined to adopt--in
which the EPA declared that every source and every nation must be
required to ``do their part'' to combat global climate change.
Implementation of the Endangerment Finding since 2009 has shown the
extraordinary consequences of this assertion of authority, including an
increasing trend toward forcing a shift from internal combustion engine
(ICE) vehicles to EVs for virtually all classes of LD, MD, and HD
vehicles.
Next, we conclude that Congress did not clearly authorize the EPA
to decide this question when it empowered the Administrator to
``prescribe . . . standards'' for new motor vehicle and engine
emissions under CAA section 202(a)(1). The general nature of the
statutory text and the more specific authorities and commands
throughout CAA section 202, as well as additional provisions throughout
the CAA, leave no room for doubt that Congress knew how to, and did
not, expressly authorize the regulation of vehicle and engine GHG
emissions. On that basis, we determine that the Endangerment Finding
and resulting GHG emission standards exceeded our statutory authority
and must be rescinded. That conclusion follows from the Supreme Court's
decisions in UARG and West Virginia and is consistent with
Massachusetts, which held that GHGs fell within the definition of ``air
pollutant'' but did not interpret the scope of our authority to
regulate air pollutants that cause, or contribute to, air pollution
which may reasonably be anticipated to endanger public health or
welfare.
1. Final Rationale
Applicability of the Major Questions Doctrine. In recent decisions
construing the scope of the EPA's statutory authority to regulate GHGs,
the Supreme Court has emphasized that the `` `history and breadth of
the authority' '' asserted by an agency and ``the `economic and
political significance' of that assertion'' provide `` `a reason to
hesitate before concluding that Congress' meant to confer such
authority.'' West Virginia, 597 U.S. at 721 (quoting Brown &
Williamson, 529 U.S. at 159-60); accord UARG, 573 U.S. at 324. Whether
viewed as an ordinary tool of statutory interpretation that looks to
the structure of the regulatory scheme \149\ or a clear statement rule
that implements nondelegation and separation of power principles,\150\
the major questions doctrine requires us to identify ``more than a
merely plausible textual basis'' when asserting authority to decide a
significant policy issue on Congress' behalf. Id. at 723.
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\149\ Biden v. Nebraska, 600 U.S. 477, 507-21 (2023) (Barrett,
J., concurring).
\150\ West Virginia, 597 U.S. at 735-51 (Gorsuch, J.,
concurring).
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In UARG, the Supreme Court applied the major questions doctrine to
reject our attempt to expand the number of stationary sources subject
to the CAA's PSD and Title V permitting requirements based on their GHG
emissions. 573 U.S. at 310-13.\151\ The Court held that the EPA had
``exceeded its statutory authority when it interpreted the Clean Air
Act to require PSD and Title V permitting for stationary sources based
on their greenhouse gas emissions'' and ``may not treat greenhouse
gases as a pollutant'' in this PSD and Title V contexts. Id. at 333. In
reaching this conclusion, the Court found that our interpretation of
the statute and related ``tailoring rule'' that exempted many sources
to address workability concerns was ``unreasonable because it would
bring about an enormous and transformative expansion in EPA's
regulatory authority without clear congressional authorization.'' Id.
at 324. Citing earlier major questions doctrine precedents, the Court
noted that ``a measure of skepticism'' is required when ``an agency
claims to discover in a long-extant statute an unheralded power to
regulate `a significant portion of the American economy,' '' id.
(quoting Brown & Williamson, 529 U.S. at 159), and that ``[w]e expect
Congress to speak clearly if it wishes to assign to an agency decisions
of vast `economic and political significance,' '' id. (quoting Brown &
Williamson, 529 U.S. at 160).
---------------------------------------------------------------------------
\151\ See 42 U.S.C. 7470-92, 7661 et seq.
---------------------------------------------------------------------------
In West Virginia, the Supreme Court again applied the major
questions doctrine to reject our attempt to shift the power grid away
from using fossil fuels through GHG emission guidelines for existing
power plants under CAA section 111(d). 597 U.S. at 711-15.\152\ The
Court noted that when interpreting a grant of regulatory authority, the
inquiry includes the question ``whether Congress in fact meant to
confer the power the agency has asserted.'' Id. at 721. The Court
explained that the major questions doctrine applies when ``the `history
and breadth of the authority that [the agency] has asserted,' and the
`economic and political significance' of that assertion, provide `a
reason to hesitate before concluding that Congress' meant to confer
such authority.'' Id. (quoting Brown & Williamson, 529 U.S. at 159-60).
In such cases, ``both separation of powers principles and a practical
understanding of legislative intent make us `reluctant to read into
ambiguous statutory text' the delegation claimed to be lurking there,''
and ``[t]he agency instead must point to `clear congressional
authorization' for the power it claims.'' Id. at 723 (quoting UARG, 573
U.S. at 324). Applying that standard, the Court held that our statutory
authority to establish emission limits under CAA section 111(a)(1) and
(d) ``is not close to the sort of clear authorization required by our
precedents.'' Id. at 732.
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\152\ See 42 U.S.C. 7411(d). The EPA had also issued GHG
performance standards for new and modified fossil fuel-fired power
plants under CAA section 111(b) that triggered the Agency's
authority to issue guidelines for existing sources under CAA section
111(d). The new source standards were not before the Supreme Court
in West Virginia.
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The Endangerment Finding implicates the major questions doctrine
for many of the same reasons the Supreme Court applied it in UARG and
West Virginia. By asserting authority to regulate in response to global
climate change concerns, the EPA `` `claim[ed] to discover in a long-
extant statute an unheralded power' representing a `transformative
expansion in [its] regulatory authority.' '' West Virginia, 597 U.S. at
724 (quoting UARG, 573 U.S. at 324). From 1965 to 2009, we invoked CAA
section 202(a)(1) consistent with the more specific direction provided
elsewhere in section 202 regarding the
[[Page 7724]]
air pollution Congress intended the EPA to address under this
authority. As noted in section III.A of this preamble, the 15 final
rules we identified as invoking CAA section 202(a)(1) prescribed
standards for air pollution problems enumerated in the statute,
including HC and other VOCs, NOX, PM, and certain air
toxics. Critically, Congress repeatedly amended the statute to instruct
the EPA what, when, and how to regulate with respect to vehicle and
engine emissions. For example, the 1970 CAA included instructions to
regulate CO, HCs, and NOX under CAA section 202(a) now
codified as amended in CAA section 202(b).\153\ The 1990 CAA amendments
included additional instructions to regulate CO, certain HCs,
NOX, and PM.\154\ These final rules carried out Congress'
instruction to use CAA section 202 in particular ways and did not
purport to use CAA section 202(a)(1) as a blanket authorization to
explore new vistas on a discretionary basis.
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\153\ Public Law 91-604, section 6, 84 Stat. 1676, 1691.
\154\ Public Law 101-549, section 203, 104 Stat. 2399, 2474.
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Given this history, the novel use of CAA section 202(a)(1) in the
Endangerment Finding is similar to the use of CAA section 111(d)
addressed in West Virginia. There, the Supreme Court found that the
EPA's use of the provision in a more limited fashion prior to the Clean
Power Plan counseled in favor of applying the major questions doctrine,
noting that `` `just as established practice may shed light on the
extent of power conveyed by general statutory language, so the want of
assertion of power by those who presumably would be alert to exercise
it, is equally significant in determining whether such power was
actually conferred.' '' 597 U.S. at 725 (quoting FTC v. Bunte Bros.,
Inc., 312 U.S. 349, 352 (1941)). We further note that the regulatory
actions reviewed in UARG and West Virginia were predicated in part on
the Endangerment Finding, and the PSD and Title V rules in UARG and
existing source emission guidelines in West Virginia are similar in
scope, approach, and economic impact as the GHG emission standards for
new motor vehicles and engines promulgated to fulfill the mandatory
duty triggered by the Endangerment Finding.
Moreover, as a consequence of the novel approach taken in the
Endangerment Finding to endangerment and contribution, our GHG emission
standards reflect an increasing trend toward mandating a shift from
gasoline- and diesel-fueled vehicles to EVs on the theory that a
substantial reduction in GHG emissions is necessary to address global
climate change concerns.\155\ This trend was evident in our earliest
GHG emission standards rulemakings and became increasingly clear over
time as the standards increased in stringency to the point where
alternative compliance options were increasingly infeasible or
unattractive for regulated parties. The underlying policy of forcing
such a transition is also evident from the Agency's statements and
actions on related issues. For further discussion of relevant
regulatory history and implementation details, both of which generated
significant public input during the comment period, see the Response to
Comments document in the docket for this rulemaking.
---------------------------------------------------------------------------
\155\ 89 FR 27842, 27844 (Apr. 18, 2024).
---------------------------------------------------------------------------
Mandating a shift in the national vehicle fleet from one type of
vehicle to another is indistinguishable from the emission guidelines at
issue in West Virginia, which were calculated to force a shift from one
means of electricity generation to another. This increasing regulatory
trend has borne out over time given the limits of using GHG emission
control technologies applicable to new motor vehicles and engines that
comport with the magnitude of the problem identified in the
Endangerment Finding. As discussed later in this preamble, even
eliminating all GHG emissions from all U.S. vehicles and engines would
have only a de minimis impact on GMST and GSLR trends as a proxy for
adverse health and welfare impacts. See section V.C of this preamble
and the Response to Comments document for further discussion.
It is `` `highly unlikely that Congress would leave' to `agency
discretion' the decision'' whether and how many consumers and
manufacturers in the United States may use the ICE in their vehicles.
West Virginia, 597 U.S. at 729 (quoting MCI Telecomms. Corp. v. AT&T
Co., 512 U.S. 218, 231 (1994)). As the Supreme Court noted with respect
to coal-based electricity generation, such a policy decision involves
``basic and consequential tradeoffs,'' and ``Congress certainly has not
conferred a like authority upon EPA anywhere else in the Clean Air
Act.'' Id. Until the Endangerment Finding, we had never invoked CAA
section 202(a)(1) to regulate in response to global climate change
concerns, whether through a fuel-shifting strategy or any other means.
That history is telling because although CAA section 202(a)(1) has
existed in substantially similar form since 1967, ``the EPA had never
regulated in that manner, despite having issued many prior rules
governing'' vehicle and engine emissions. Id. When Congress intended
the EPA to regulate the type of fuels that propel vehicles, it provided
express and detailed authority to do so in other provisions. CAA
section 211 authorizes the Agency to regulate fuel and fuel additives,
including by requiring registration and controlling or prohibiting the
manufacture, distribution, or sale of fuel or fuel additives if the
Administrator determines that ``any emission product of such fuel or
fuel additive causes, or contributes, to air pollution or water
pollution . . . that may reasonably be anticipated to endanger the
public health or welfare'' or significantly impair the performance of
any generally used emission control device.\156\ Moreover, CAA section
211(o) sets out detailed requirements for the Agency's RFS program,
which involves setting annual renewable fuel volume requirements
applicable to refiners, blenders, distributors, and importers of
transportation fuel.\157\ Both of these provisions, with respect to the
Nation's policy approach to GHGs generally and transportation fuel
specifically, indicate that Congress knows how to establish policy on
the subject and has declined to empower the EPA to decide for itself
whether and how to respond to global climate change concerns.
---------------------------------------------------------------------------
\156\ 42 U.S.C. 7545(a)-(c).
\157\ 42 U.S.C. 7545(o).
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Both before and since the Endangerment Finding, `` `Congress
considered and rejected' multiple times'' legislation that would have
authorized or required the EPA to regulate GHG emissions from vehicles,
engines, and additional sources. West Virginia, 597 U.S. at 731
(quoting Brown & Williamson, 529 U.S. at 144). This history is
particularly relevant because of the established pattern through the
1990 CAA amendments of Congress adding additional emissions control
authority and obligations to CAA section 202. From 2007 to 2009,
Congress considered legislation--supported by the President and
Administrator in office at the time of the Endangerment Finding--that
would have authorized or required the EPA to prescribe emissions
regulations for GHGs. For example, the Safe Climate Act of 2007 would
have adopted findings and policies with respect to limiting global
temperature increase, required various forms of international
cooperation, and added a new Title VII to the CAA instructing the EPA
to achieve phased GHG emission reduction targets and regulate GHG
emissions
[[Page 7725]]
under CAA section 202.\158\ Similarly, the American Clean Energy and
Security Act of 2009 would have required international cooperation and
added new titles to the CAA requiring the EPA to, among other things,
regulate GHG emissions under CAA section 202.\159\ Neither bill was
enacted through the legislative process, and Congress has since
declined to adopt similar legislation.\160\
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\158\ H.R. 1590, 110th Cong. (2007). This bill was presented in
the House of Representatives and never received a vote.
\159\ H.R. 2454, 111th Cong. (2009). This bill, introduced on
May 15, 2009--a month after the EPA proposed the Endangerment
Finding--passed the House of Representatives on June 26, 2009, by a
219-212 margin but never received a vote in the Senate. The
President and Administrator at the time expressed a strong
preference for legislation but also a willingness to resolve
legislative inaction by administrative means, and the Agency
ultimately finalized the Endangerment Finding on December 7, 2009.
\160\ Congress's pattern of not providing the EPA such authority
extends long before the 2009 Endangerment Finding as well. See Coal.
for Responsible Regulation, 2012 U.S. App. LEXIS 25997, at * 36-37
(Brown, J., dissenting from denial of rh'g en banc) (noting Congress
expressly rejected proposals offered during the drafting of the 1990
CAA Amendments that would have authorized the EPA to regulate GHGs).
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When Congress has addressed GHGs individually or collectively, it
has not granted the EPA broad regulatory authority to ``prescribe . . .
standards'' under CAA section 202(a)(1). As noted above, Congress
enacted the RFS program to promote energy independence while reducing
GHG emissions through a detailed regulatory scheme. With respect to
HFCs, Congress enacted a comprehensive phaseout scheme in the 2020
American Innovation and Manufacturing (AIM) Act, which includes
detailed instructions, timelines, and requirements for implementation
and allows some uses to continue under certain conditions.\161\ With
respect to CO2, Congress opted for a carrot rather than a
stick by authorizing a tax credit to incentivize underground
sequestration that mitigates emissions.\162\ With respect to methane,
Congress amended the CAA in 2021 through the Inflation Reduction Act of
2022 (IRA) to require us to establish a waste emissions charge for
certain sources structured to incentivize emissions reductions over
time.\163\ When addressing GHGs and global climate change concerns more
generally, Congress has used non-regulatory tools that incentivize,
rather than mandate, changes in manufacturing and consumer choice,
including through additional funding provisions in the IRA.\164\
Multiple instances of recent legislation addressing GHGs individually
and through distinct regulatory approaches suggests that Congress views
such policy decisions as economically and politically significant and
not adequately addressed by general statutory authorities enacted in
response to different problems.
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\161\ Public Law 116-260, Div. S, 134 Stat. 1182, 2255-71
(codified at 42 U.S.C. 7675 et seq.).
\162\ 26 U.S.C. 45Q. In 2020, Congress also instructed us to
recommend improvements to SDWA permitting procedures for injection
wells used in carbon sequestration and appropriated additional
fundings for the ``Class VI'' permitting process. Public Law 116-
260, Div. G, Title II, 134 Stat. 1182, 1507-16.
\163\ Public Law 117-169, section 60113, 136 Stat. 1818, 2074
(codified at 42 U.S.C. 7436).
\164\ See, e.g., Public Law 117-169, sections 60101-03, 60107,
60114, 60201, 136 Stat. 1818, 2063-66, 2069, 2076, 2078 (codified at
42 U.S.C. 7432-35, 7437-38).
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The EPA notes that Congress has continued to revise these air
pollutant-specific measures and nonregulatory tools as part of an
ongoing national debate over the appropriate response to global climate
change concerns. On July 4, 2025, President Trump signed into law
significant new legislation enacted by Congress, the One Big Beautiful
Bill Act (OBBB),\165\ which repealed several relevant measures adopted
in the IRA and rescinded the EPA's appropriations to carry out several
funding programs related to GHG emissions. Among other things, Congress
prohibited the Agency from collecting the waste emission charge for
methane for ten years beyond the original statutory collection date,
rescinded funding to administer grant programs in CAA sections 132 and
135-38, and repealed CAA section 134, which had included a section-
specific definition of ``greenhouse gas'' applicable to the grant
program set out in that section.\166\ This legislation, which was the
product of substantial national debate and revised and rescinding
funding for provisions of the IRA that were themselves the product of
substantial national debate, indicates that the EPA erred in attempting
to resolve significant policy issues on its own accord in the
Endangerment Finding.
---------------------------------------------------------------------------
\165\ Public Law 119-21.
\166\ 42 U.S.C. 7434(c)(2) (2022).
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Congress has also recently disapproved several actions taken by the
EPA with respect to GHG emissions. On May 19, 2025, President Trump
signed into law a resolution adopted by Congress under the
Congressional Review Act (CRA) to void our final rule implementing the
waste emission charge added to the CAA in 2021.\167\ And on June 12,
2025, President Trump signed into law three resolutions adopted by
Congress under the CRA \168\ to void waivers we granted under CAA
section 209 that allowed California and participating States to enforce
GHG emission regulations for motor vehicles and engines, up to and
including zero-emission standards that mandated a shift to electric
vehicles.\169\ These disapproval resolutions further demonstrate the
economic and political significance of the EPA's GHG emission
regulations and reinforce the understanding that Congress intends to
reserve such major questions of policy for itself. See West Virginia,
597 U.S. at 731-32.
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\167\ Public Law 119-2; see 90 FR 21225 (May 19, 2025).
\168\ H.J. Res. 87; H.J. Res. 88; H.J. Res. 89; see also Diamond
Alt. Energy, LLC v. EPA, 606 U.S. 100, 107 n.1 (2025); Statement by
the President (June 12, 2025): https://www.whitehouse.gov/briefings-statements/2025/06/statement-by-the-president/.
\169\ For example, California's Advanced Clean Cars II required
an increasing amount of EVs to be sold so that by 2035 100 percent
of new cars and light trucks sold in California would be zero-
emission vehicles, including PHEV. See California Air Resources
Board, California moves to accelerate to 100% new zero-emission
vehicle sales by 2035, available at https://ww2.arb.ca.gov/news/california-moves-accelerate-100-new-zero-emission-vehicle-sales-2035.
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Conclusion. Under the major questions doctrine, we conclude that
the EPA lacks the ``clear congressional authorization'' required for
the novel approach taken in the Endangerment Finding and resulting GHG
emission standards and must rescind these actions. West Virginia, 597
U.S. at 723 (quoting UARG, 573 U.S. at 324). Our statutory authority
under CAA section 202(a)(1) to ``prescribe . . . standards'' does not
clearly authorize the EPA to regulate in response to global climate
change concerns or, in issuing such regulations, to trend toward
mandating a shift from gas- and diesel-fueled vehicles to EVs. This
conclusion follows whether the major questions doctrine is viewed as an
ordinary interpretive principle or a protection against violations of
the separation of powers. As discussed previously in section V.A.1 of
this preamble, an interpretation of CAA section 202(a)(1) that permits
the EPA to define and regulate any ``air pollution'' the Agency
believes may harm public health or welfare, broadly defined, would
raise serious absurdity and nondelegation concerns. Properly
interpreted, the statute does not and need not raise such concerns
given the best reading of the statute or application of the major
questions doctrine.
In West Virginia, the Supreme Court held that our authority under
CAA section 111 ``to establish emission caps at a level reflecting `the
application of the best system of emission reduction . . . adequately
demonstrated' '' did not
[[Page 7726]]
clearly authorize the EPA to issue emission guidelines that addressed
global climate change concerns by mandating a shift away from coal-
generated electricity. 597 U.S. at 732. Similarly, in UARG, the Court
held that our PSD and Title V authorities could not fully be extended
to GHG emissions because those provisions ``are designed to apply to,
and cannot rationally be extended beyond, a relative handful of large
sources capable of shouldering heavy substantive and procedural
burdens.'' 573 U.S. at 303. In these and other recent precedents, the
Court has made clear that the express statutory authority required by
major questions doctrine requires more than general language conferring
``a merely plausible textual basis for the agency action.'' West
Virginia, 597 U.S. at 723.\170\
---------------------------------------------------------------------------
\170\ See, e.g., Nebraska, 600 U.S. at 506-07 (Department of
Education lacked clear authority to forgive student loans under
statutory language authorizing the Secretary to ``waive or modify
any statutory or regulatory provision applicable to the student
financial assistance programs . . . deem[ed] necessary in connection
with a war or other military operation or national emergency'');
Ala. Ass'n of Realtors v. HHS, 594 U.S. 758 (2021) (CDC lacked clear
authority to impose eviction moratorium during the COVID-19 pandemic
under language permitting ``such regulations as in [the Surgeon
General's] judgment are necessary to prevent the introduction,
transmission, or spread of communicable diseases'').
---------------------------------------------------------------------------
These cases control the analysis of our authority under CAA section
202(a). As in West Virginia, our statutory authority and the findings
required to invoke that authority do not clearly authorize the approach
taken in the Endangerment Finding and subsequent regulations. And as in
UARG, our statutory authority to ``prescribe . . . standards'' for
emissions of certain air pollutants does not clearly authorize using
the CAA's vehicle-emission control scheme to address global climate
change concerns. As discussed above, the Endangerment Finding did not
limit itself to considering the impacts of GHG emissions from new motor
vehicles and engines. Rather, the Endangerment Finding reviewed the
totality of adverse impacts from climate change attributed to all
anthropogenic sources of GHG emissions worldwide and asserted
jurisdiction over CAA section 202(a) sources by finding they
contributed to such impacts by emitting more than de minimis quantities
of GHGs. That understanding has permeated our GHG emission rulemakings
since 2009, and we have attempted to apply that framework to our
distinct regulatory authorities across the rest of the CAA.
In Massachusetts, the Supreme Court disagreed with the EPA's
argument that GHGs were not ``air pollutants'' because Congress had not
revisited CAA section 202(a) in amending the CAA in 1990. 549 U.S. at
512-13. The Court found that our reliance on Brown & Williamson to
support that argument was misplaced because unlike the ban on tobacco
products at issue in that case, ``EPA jurisdiction would lead to no
such extreme measures.'' Id. at 531. The Court also found that unlike
the FDA's earlier statements on tobacco products, the ``EPA had never
disavowed the authority to regulate greenhouse gases'' and had issued a
memorandum in 1998 suggesting that we had such authority. Id.
Massachusetts did not consider or have reason to interpret the
scope of the EPA's authority under CAA section 202(a) given our
position in the 2003 Denial that GHGs are not ``air pollutant[s]''
under any provision of the statute. Rather, Massachusetts rejected our
position that GHGs are ``categorically'' excluded from the CAA and
remanded for the Administrator to determine whether four GHGs met the
standard in CAA section 202(a). UARG, 573 U.S. at 320. Further,
Massachusetts must be read together with the Supreme Court's decisions
in West Virginia and UARG, which applied the major questions doctrine
to statutory provisions similar to CAA section 202(a), as well as other
relevant precedents decided since 2007.\171\ The decision in
Massachusetts necessarily does not reflect consideration of these
precedents or additional legislative and regulatory developments since
that time. As noted above, the EPA's rulemakings have not been limited
to emission standards as anticipated in Massachusetts, but instead
reflect an increasing trend toward mandating a transition toward EVs
for virtually all classes of LD, MD, and HD vehicles.
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\171\ We note that recent Supreme Court decisions have not cited
Massachusetts as a precedent applying, or declining to apply, the
major questions doctrine. See, e.g., Nebraska, 600 U.S. 477; West
Virginia, 597 U.S. 697.
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2. Summary of Comments and Updates Since Proposal
The EPA received comments from a variety of stakeholders supporting
and criticizing the legal rationale set out in the proposed rule.
Commenters supporting the rescission and repeals pointed to West
Virginia as virtually conclusive with respect to the applicability and
outcome of the major questions doctrine analysis. These commenters
generally agreed that the Endangerment Finding itself runs afoul of the
doctrine by launching the EPA into a policy field that Congress has not
decided whether and how to enter as a regulatory matter and,
separately, that the EPA's increasing trend in GHG emission standard
rulemakings toward forcing a shift toward EVs also runs afoul of the
doctrine. Some commenters argued that the doctrine applied to the GHG
emission standards but not the Endangerment Finding, including because
the standards have increasingly trended toward forcing a shift to EVs.
Commenters opposing the rescission and repeals generally argued that
the Supreme Court's decision in Massachusetts must be read as shielding
CAA section 202(a) from the major questions analysis. Some of these
commenters also insisted that the regulation of GHG emissions from new
motor vehicles and engines is not economically or politically
significant, or that CAA section 202(a)(1) expressly authorizes the EPA
to assert such authority by using broad language intended to achieve
what they assert is the statute's precautionary purpose. The final
rationale set out in the preceding section of the preamble reflects
this input by including certain contentions raised by commenters and
additional analysis developed in response to criticisms raised during
the public comment period. In this subsection, we summarize major
themes presented in the comments received along with our high-level
responses. For detailed comment summaries and our full responses
thereto, please see the Response to Comments document in the docket for
this rulemaking.
Comment: Commenters supportive of the proposal agreed that
prescribing GHG emission standards in response to global climate change
concerns is a major question of social, economic, and political
importance and that the EPA lacked clear congressional authorization to
issue the Endangerment Finding and associated GHG emission standards
authorized by that invocation of authority. These commenters argued
that by purporting to resolve significant aspects of the climate change
debate by deciding the Nation's policy response for itself in the first
instance, the EPA asserted an unheralded authority that infringed on
Congress's prerogatives. Several of these commenters argued that the
Endangerment Finding preempted Congress by purporting to resolve an
issue that was being actively debated and negotiated on the House and
Senate floors in 2009 and identified additional instances in which
Congress considered but declined to adopt legislation that would have
granted the very authority that the EPA asserted in the Endangerment
Finding. Such commenters also argued that congressional inaction means
that we
[[Page 7727]]
never had authority to regulate GHGs in this manner, and that authority
cannot be manufactured by placing the burden on Congress in the
aftermath of the Endangerment Finding to affirmatively intervene to
override the Agency's actions.
Response: The EPA agrees with the commenters that the major
questions doctrine applies to the authority we asserted under CAA
section 202(a)(1) for the first time in the 2009 Endangerment Finding.
In that standalone action, the EPA established the legal foundation to
regulate GHG emissions under CAA section 202(a)(1) and knowingly
triggered a statutory obligation to regulate GHG emissions not only in
the transportation sector, but in other respects as well, including the
stationary source permitting context. The importance and extraordinary
consequences of that decision were both foreseeable and foreseen by the
EPA at the time, as evidenced by the 2008 ANPRM and statements made and
actions taken by the EPA in 2009 and 2010. See, e.g., 73 FR 44355
(``[I]f EPA were to regulate [GHG] emissions from motor vehicles under
the Clean Air Act, then regulation of smaller stationary sources that
also emit GHGs--such as apartment buildings, large homes, schools, and
hospitals--could also be triggered. . . . The potential regulation of
greenhouse gases under any portion of the [CAA] 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.''); 74 FR 66502 (``Once the final affirmative
contribution and endangerment findings are made, EPA has the authority
to issue the final emission standards for new light-duty motor
vehicles.''). Intervening events, including those addressed in UARG and
West Virginia, have further demonstrated what was widely understood in
2009--the Endangerment Finding launched an entirely new field of
regulation in which the EPA has applied, or attempted to apply,
significant and costly regulations on virtually all major sectors of
the American economy.
In this way, the EPA's invocation of authority in the Endangerment
Finding followed by the mandatory issuance of regulations operates
similarly to the assertion of authority to which the Supreme Court
applied the major questions doctrine in West Virginia. The Agency's
emission guidelines for existing power plants under CAA section 111(d)
also imposed costs and forced generation shifting in an indirect
manner. First, we issued regulations determining the amount of
pollution reduction to be achieved; second, States were required to
submit plans containing the emissions restrictions they intended to
implement and enforce to achieve those reductions; and third, we would
review those State plans for consistency with CAA requirements and
allow them to enter into force through an approval or substitute State
plans for a Federal plan in the event of disapproval. Similarly here,
the EPA asserted authority in the Endangerment Finding that, by
operation of law, triggered an obligation to prescribe GHG emission
standards under CAA section 202(a)(1), triggered stationary source
permitting requirements, and served as the basis for extending the
reach of GHG emission regulations to additional sources, all as
predicted in the 2008 ANPRM.
Further, the new motor vehicle standards issued by the EPA
separately and independently trigger the major questions doctrine by
forcing a transition toward the use of EVs rather than the ICE in a
manner similar to the generation shifting at issue in West Virginia. As
early as the EPA's first light-duty vehicle rule in 2010, the Agency
relied on and knew its regulations would lead to increased EV
production. See 75 FR 25324, 25332 (May 7, 2010) (noting that the
``commercialization of [EVs] and plug-in hybrids,'' as well as
``increased use of start-stop technology,'' were available avenues for
compliance).
Comment: Adverse commenters asserted that the major questions
doctrine does not apply to CAA section 202(a)(1) because of what they
describe as a holding in Massachusetts that the regulation of GHGs
under that provision is permissible and/or not a major question. These
commenters cited to the Supreme Court's discussion of Brown &
Williamson in that decision, along with statements made by the Agency
in prior GHG emission standards rulemakings, to support the contention
that the major questions analysis is inapplicable or that precedent
establishes the requisite clear authorization.
Response: The EPA disagrees with these comments. As explained in
section V.B.1 of this preamble and discussed further in the Response to
Comments document, the Supreme Court drew no such distinctions in West
Virginia when it held that the major questions doctrine applies to
``all corners of the administrative state,'' even if the ``regulatory
assertions had a colorable textual basis.'' 597 U.S. at 721-23
(citation omitted). The Court did not appear to understand itself to be
applying the major questions doctrine in Massachusetts, and has not, in
subsequent cases, treated Massachusetts as an example of applying or
declining to apply the doctrine. Rather, the Court in Massachusetts
distinguished Brown & Williamson on its facts. That discussion does not
stand for the proposition that CAA section 202(a)(1) is immune from
major questions scrutiny, and many of the distinctions drawn in
Massachusetts as to Brown & Williamson are now themselves
distinguishable given the EPA's subsequent reasoning in the
Endangerment Finding and actions taken to implement the Endangerment
Finding since 2009.
Comment: Adverse commenters asserted that if major questions
doctrine is relevant here, its principles cut against what they
described as the EPA's novel interpretation of CAA section 202(a)(1).
These commenters argued that for nearly 20 years, Congress has declined
to overturn what commenters described as the judicial decisions
upholding the EPA's authority to regulate GHG emissions or to amend CAA
section 202 to restrict the Agency's authority in this respect.
Commenters asserted that rescinding the Endangerment Finding would
itself create an abrupt reordering in an area of economic and political
significance and is an assertion of authority that would be both novel
and dubious and potentially threaten the separation of powers.
Commenters asserted that under the major questions doctrine, the
EPA is not able to reverse what they described as the Agency's
longstanding interpretation dating back to the Endangerment Finding
without being given authority by Congress to do so. Commenters stated
that Congress has enacted numerous laws that have recognized GHGs are
air pollutants subject to regulation under the CAA. Commenters argued
that Massachusetts and the Endangerment Finding have been established
law since 2009 and that Congress has known about and enacted
legislation on numerous occasions that recognize and affirm the legal
interpretations made by the Supreme Court in Massachusetts and by the
Agency in the Endangerment Finding.
Response: The EPA disagrees with commenters and concludes the major
questions doctrine supports the rescission of the Endangerment Finding
and repeal of associated GHG emission standards. The EPA's
interpretation of CAA section 202(a)(1) is not novel. As explained in
sections III.A and IV.A of this preamble, it reflects the Agency's
longstanding practice in applying CAA section 202(a)(1) for the four
decades
[[Page 7728]]
prior to 2009. Moreover, rescinding the Endangerment Finding and
repealing the associated GHG emission standards does not trigger the
major questions doctrine because an agency's ability to reconsider,
revise, and repeal prior actions is not an unheralded assertion of
authority. As explained in section IV.A of this preamble, it is well
established that an agency may reconsider, revise, and repeal prior
actions unless the relevant statute provides otherwise, which is not
the case here.
In addition, the EPA disagrees with commenters' representations of
the scope of the Supreme Court's decision in Massachusetts and
characterizations of congressional actions since 2009. Tellingly,
commenters point to no occasion in which Congress has adopted
legislation that expands the scope of the EPA's authority to regulate
GHG emissions from mobile or stationary sources. As noted elsewhere in
this preamble, Congress considered between 2007 and 2009 draft
legislation--emphatically supported by President Obama and the
Administrator who issued the Endangerment Finding--that would have
substantially revised the CAA to give the EPA express authority to
regulate GHG emissions, including under Title II. That legislation
failed to pass, and the relatively limited number of non-regulatory
provisions Congress has enacted since that time relate either to non-
regulatory contexts or support our conclusion with respect to CAA
section 202(a)(1) by indicating that Congress has adopted more
detailed, particular solutions when it sought to address global
problems, as with amendments to the RFS program and the AIM Act. This
history falls well short of the standard courts have applied for
inferring legislative acquiescence to either commenters' reading of
Massachusetts or the EPA's assertion of authority in the 2009
Endangerment Finding. Ultimately, commenters appear to be asserting
what is more properly understood as reliance interests on prior actions
taken by the Agency. Because the EPA concludes that we lack statutory
authority to regulate in response to global climate change concerns
under CAA section 202(a)(1), we cannot respond to such asserted
reliance interests by retaining the Endangerment Finding and associated
GHG emission standards on that basis.
Indeed, commenters inadvertently reinforce why the major questions
doctrine applies to the Endangerment Finding and necessitates its
rescission. If rescission of the Endangerment Finding is significant
enough to trigger the major questions doctrine, there is no persuasive
reason to conclude that issuing the Endangerment Finding to initiate
the resulting GHG regulatory program does not similarly trigger major
questions scrutiny. Were commenters correct that only rescission
triggers the doctrine, the result would be an untenable rule by which
an Agency can expand its statutory authority through attrition even if
application of the doctrine would otherwise require a different result.
Comment: Some commenters said that they support the EPA's
application of the major questions doctrine to the vehicle standards
that effectively mandated EVs as a purported emissions control measure
for motor vehicles powered by ICEs. They stated that as the EPA points
out in the proposed rule, effectively mandating a shift away from ICE
vehicles under CAA section 202(a)(1) is conceptually indistinguishable
from the EPA's failed attempt to mandate generation shifting by reduced
utilization of coal-fired power plants under CAA section 111(d).
Commenters argued that both actions involve claims of novel and
expansive regulatory authority under longstanding law, both have
fundamental effects on key national industries and on the national
economy, Congress has grappled repeatedly over time with whether and
how GHG emissions from these industries should be regulated, and
neither action is grounded in a clear statutory mandate.
Commenters also said that the EPA's 2024 HD GHG Emission Standards
Rule, without question, meet all the criteria for rescission under the
major questions doctrine. These commenters argued that the Supreme
Court in West Virginia held open the door for the rescission of what
commenters described as sweeping EV truck mandates that impact broad
segments of the national economy. Commenters argued that these
standards are a direct analogue to the regulations invalidated in West
Virginia.
Conversely, other commenters argued that the major questions
doctrine does not apply to the 2024 GHG Emission Standards Rules and
that the EPA did not explain or show awareness of its change in
position from what these commenters described as the Agency's detailed
consideration and rejection of major questions doctrine arguments in
responding to comments on the 2024 GHG Emission Standards Rules.
Response: The EPA concludes that the major questions doctrine
applies to the GHG emissions standards for LD, MD, and HD vehicles that
the Agency promulgated in 2024, as discussed in the final rule preamble
and with the Response to Comments document. We acknowledge that the
Agency previously asserted that the 2024 GHG Emission Standards Rules
did not violate the major questions doctrine. As explained in this
final action, however, we now conclude that the arc of regulation since
2009 evinces a clear march toward requiring widespread adoption of EVs
by manufactures and American consumers, such that the major questions
doctrine applies in this respect as well. Accelerating the transition
to EVs is realistically the only way for many regulated parties to
comply with the stringent emission standards adopted in 2024. At least
two auto manufacturers noted the compliance challenges with the current
standards and cast doubt on their attainability, particularly in light
of reduced EV demand. As demonstrated by the manufacturers' comments,
the EPA's GHG emissions standards are difficult to achieve without
increasing EV production.
Further, certain events have overtaken aspects of the EPA's
analysis in its prior rulemakings. For example, the IRA was largely
overtaken by the OBBB, and Congress has disapproved of the EPA's
approval of the California waiver under the CRA. The market has also
changed since the 2024 GHG Emission Standards Rules: EV demand is down,
gas prices are generally down, and EV prices are generally higher than
the EPA anticipated.
In effect, the main compliance option for the 2024 GHG Emission
Standards Rules was for manufacturers to increase EV production. As
discussed in greater detail in the Response to Comments document, the
EPA first incentivized EV production in 2010 and projected that
compliance with many of its standards in the years since then would
include surpassing the amount of EVs that manufacturers would have
produced based on market forces alone. The totality of the EPA's
actions, when viewed holistically, show a clear path towards a changed
reality on the ground of more EVs.
C. Eliminating GHG Emissions From Motor Vehicles and Engines Would Be
Futile
The EPA is also finalizing as proposed that the Agency should not
and need not make an endangerment finding under CAA section 202(a)(1)
when exercising the regulatory authority conferred by that provision
would have no meaningful impact on the identified dangers. The comments
and data received in response to the proposed rule, as well as the
modeling analysis we performed to evaluate these submissions, indicates
that GHG
[[Page 7729]]
emission standards under CAA section 202(a)(1) have no more than a
trivial effect on the key changes that the Endangerment Finding
identified as causing adverse health and welfare impacts. The
Endangerment Finding avoided confronting this question by severing the
findings from consideration of the resulting regulations, and we
focused in subsequent rulemakings on the emissions reductions potential
of the standards rather than the impacts on health and welfare. Upon
further review, we conclude that this approach is not consistent with
the best reading of the statute or the requirement that regulations be
reasonable and reasonably explained. CAA section 202(a)(1) instructs
the EPA to regulate in furtherance of public health and welfare, not to
reduce emissions regardless whether such reductions have any material
health and welfare impact.
Specifically, we are finalizing that the potential for emission
standards to yield more than de minimis gains for health or welfare are
relevant and should be considered when applying CAA section 202(a)(1).
We recognized in the Endangerment Finding that the relative
contribution of GHG emissions to global concentrations from new motor
vehicles and engines in the U.S. must be more than de minimis to invoke
our authority but failed to carry this logic through to the remainder
of the analysis. Background legal principles instruct that de minimis
concerns are not encompassed within the scope of general statutory
language, and the ability of regulation to address identified dangers
is relevant to whether it can be said that that the emissions
contribute to air pollution that endangers public health or welfare in
the first instance. As discussed in this subsection, comments and our
own analysis in response to comments provides that any potential impact
is de minimis. Even a complete elimination of all GHG emissions from
new motor vehicles and engines would not address the risks attributed
to elevated global concentrations of GHGs. We are finalizing that this
futility further demonstrates that CAA section 202(a)(1) does not, as a
matter of text and structure, authorize or require the EPA to prescribe
emission standards for GHG emissions from new motor vehicles and
engines.
1. Final Rationale
As discussed in section VI.A of this preamble, the EPA recognizes
that there are significant uncertainties related to climate modeling
and recognizes that there is still significant dispute regarding
climate science and modeling. However, the EPA is utilizing the climate
modeling provided within this section to help illustrate that, even
applying the assumptions of these climate models and uncertainties
contained therein, that removing all GHG emissions from new and
existing LD, MD, and HD vehicles and engines would not materially
address the health and welfare dangers attributed to global climate
change concerns in the Endangerment Finding.
The EPA utilized the EPA Optimization Model for reducing Emissions
of GHGs from Automobiles (OMEGA model) to estimate the global GHG
contributions from U.S. light- and medium duty vehicle engines, and the
EPA's MOtor Vehicle Emission Simulator (MOVES model) to estimate the
global contribution from U.S. heavy-duty vehicle engines (Table
1).\172\ The baseline global emission scenario used for this analysis
was Shared socioeconomic pathway 2 with a radiative forcing of 4.5
watts per square meter by 2100 (SSP2-4.5) (Table 1).
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\172\ Note that these scenarios did not include additional GHG
emissions from upstream refinery or energy generation processes, nor
additional emissions of hydrofluorocarbons (HFCs) from vehicle air
conditioners. The EPA separately regulates emissions from stationary
sources under statutory authorities outside the scope of this
rulemaking and, pursuant to separately enacted legislation requiring
a phase out of HFCs, regulates permissible uses of HFCs.
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The EPA used the Finite amplitude Impulse Response (v2.2.3) climate
emulator model (FaIR model) to quantify changes in global
CO2 concentration and global surface temperature associated
with the marginal change in emissions from each vehicle scenario
relative to the baseline. The FaIR model is an open-source emulator
that reasonably reflects the best available information and science but
does not include all possible Earth system processes. In FaIR,
greenhouse gas lifetimes are based on a four-box decay model that is
also a function of atmospheric and ocean temperatures and emissions of
other gases. The model accounts for radiative forcing from greenhouse
gases, aerosols, albedo changes due to land use, solar cycles, and
volcanic eruptions, given an externally defined time path for each.
FaIR uses three layers for the ocean component, as heat uptake by the
ocean controls how fast atmospheric temperature changes after a change
in radiative forcing. FaIRv2 includes uncertainty estimates that are
based on a calibration to global climate models, historical
observations, and parameter uncertainty ranges from the
Intergovernmental Panel on Climate Change. Uncertainties in climate
model parameters considered in FaIR, include the sensitivity of climate
to increases in atmospheric CO2 concentrations, forcing from
aerosol interactions with radiation and clouds, forcing from black
carbon on snow, and carbon cycle parameters. All simulations were run
with historical volcanic and solar cycle forcing, with values held
constant (solar) after 2022.
The EPA also used the Building Blocks for Relevant Ice and Climate
Knowledge (BRICK) model to quantify changes in GSLR associated with the
marginal temperature changes from each vehicle emissions scenario.
BRICK is a semi-empirical, open-source model, with four sub-components
that each model the physical changes in the four major contributors to
GSLR--glaciers and ice caps, land water storage, and ice sheets, and
thermal expansion--in response to changes in temperature. Similar to
FaIR, the BRICK model is also designed with uncertain parameters
intended to encompass the range of possible GSLR responses to a given
input of temperature and ocean heat content. Uncertainties in GSLR
parameters considered in BRICK include contributions from glaciers and
ice caps and the Antarctic and Greenland ice sheets, as well as ocean
thermal expansion, and were calibrated through a coupled physical-
statistical framework, using an adaptive Markov chain Monte Carlo
approach. Reduced complexity models like BRICK and FaIR allow for the
flexibility to analyze custom scenarios, quantitatively discern changes
between any scenarios, and characterize uncertainties surrounding
global change. The National Academies of Sciences, Engineering and
Medicine (NASEM) in a 2017 report endorsed the use of the FaIR model in
a 2017 report, and the BRICK model was developed in response to
recommendation 4-3 from the 2017 NASEM report.\173\
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\173\ National Academies of Sciences, Engineering, and Medicine.
2017. Valuing Climate Damages: Updating Estimation of the Social
Cost of Carbon Dioxide. Washington, DC: The National Academies
Press. A copy of this report is available in the docket for the
rulemaking. Available online: https://doi.org/10.17226/24651.
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The EPA modeling described above projects that global atmospheric
concentrations of CO2 will be 420.5 parts per million by
volume (ppmv) (with an associated 95 percent confidence interval (95
percent CI) of 419.1-422.1 ppmv) in 2027 and are projected to increase
in the baseline scenario to a median of 475.4 ppmv by 2050 and 533.6
ppmv by 2100. The 95 percent CI reflects the uncertainty in the FaIR
model input parameters and ranges from 461.8-484.3 ppmv in 2050 to
[[Page 7730]]
482.5-565.4 ppmv in the year 2100. Relative to 2027, concentrations of
CO2 are projected to increase in 2050 and 2100, by 55.0 ppmv
and 113.3 ppmv, respectively (Table 3). GHG emissions from on-road
vehicle exhaust in the United States are projected to contribute 2.8
ppmv (or 5 percent) and 7.4 ppmv (or 7 percent) to this global increase
by 2050 and 2100, respectively (Table 3).
The modeled GMST in 2027 is projected to be 1.35 [deg]C above pre-
industrial temperatures, defined as the average between 1850 and 1900
(Table 4). GMST in the baseline scenario is estimated to increase to
1.89 [deg]C (95 percent CI: 1.44-2.37 [deg]C) and 2.66 [deg]C (95
percent CI: 1.86-3.87 [deg]C) above preindustrial temperatures by the
years 2050 and 2100, respectively. These changes are +0.53 [deg]C (95
percent CI: 0.32-0.84 [deg]C) and +1.28 [deg]C (95 percent CI: 0.67-
2.42 [deg]C) above 2027 temperatures (Table 5). GHG emissions from on-
road vehicle exhaust in the United States are projected to contribute
to 0.013 [deg]C (95 percent CI: 0.009-0.017 [deg]C) (or 2 percent) of
this increase in GMST by 2050 and 0.037 [deg]C (95 percent CI: 0.024-
0.054 [deg]C) (or 3 percent) of this increase by 2100.
The modeled GSLR is estimated to be 25.8 cm higher in 2027 than
during the preindustrial era (1850-1900). GSLR in the baseline scenario
is projected to be 38.9 cm (95 percent CI: 28.0-49.1 cm) by 2050 and
94.3 cm (95 percent CI: 59.9-157.9 cm) by 2100 relative to
preindustrial (Table 6). These increases are roughly 12.4 cm (95
percent CI: 9.4-20.3 cm) and 69.5 cm (95 percent CI: 35.2-132.7 cm)
higher than 2027 levels (Table 7). GHG emissions from on-road vehicle
exhaust in the United States contribute to roughly 0.09 cm (0.06-1.06
cm) (or ~1 percent) of this global increase in 2050 and 1.4 cm (0.39-
4.77 cm) (or 2 percent) of this global increase by 2100.
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As shown above, the changes in GHG emissions and global GHG
concentrations by 2050 and 2100 resulting from the complete elimination
of all GHG emissions from new and existing LD, MD, and HD vehicles in
the United States would be relatively minor. Importantly, however,
changes in global emissions rates and global concentrations are not the
focus of the statutory standard for regulation in CAA section
202(a)(1). Rather, the statute instructs that the ultimate regulatory
concern is impacts from air pollution on ``health or welfare.'' The
appropriate indicator of impact is not emissions or concentrations, but
health and welfare impacts. Given the speculative, multi-faceted, and
multi-causal nature of the impacts cited in the Endangerment Finding
(e.g., hurricanes, floods, heat waves, ocean acidification, etc.), we
used for purposes of this analysis the projected impacts of the
elimination of U.S. LD, MD, and HD vehicle emissions on trends in GMST
and GSLR.
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\174\ Average annual observed CO2 concentrations in
2024 were 423 ppmv. Source: Trends in Atmospheric Carbon Dioxide
(CO2) from: https://gml.noaa.gov/ccgg/trends/global.html.
\175\ Note that observed data do not exactly correspond with
that modeled estimates, as the FaIR and BRICK modeling start in 1750
(or 1850) for estimation of both historical and future projected GHG
concentrations, temperatures, and GSLR.
\176\ Uncertainties in GSLR parameters considered in BRICK,
include but are not limited to sea level rise contributions from
glaciers and ice caps and the Antarctica and Greenland ice sheets,
as well as ocean thermal expansion. The calibration of the 10,000
parameter sets is described in: Rennert, K., Errickson, F., Prest,
B.C. et al. Comprehensive evidence implies a higher social cost of
CO2. Nature 610, 687-692 (2022). https://doi.org/10.1038/s41586-022-05224-9.
\177\ GMST observations in 2024 were 1.55 (1.42-1.68) [deg]C
relative to 1850-1900 to present from https://wmo.int/publication-series/state-of-global-climate-2024. The uncertainty in observed
temperatures is due to the uncertainty in temperature before 1900,
due to the sparsity of observations during that period.
\178\ Observations of GSLR in 2024 are 22.5 cm relative to pre-
industrial. Source: https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level.
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In this analysis, we reviewed the projected impact on GMST and GSLR
by applying two important qualifications. First, the projected impacts
on GMST and GSLR are not themselves the adverse impacts on health and
welfare relevant for purposes of the analysis. Rather, they are
imperfect proxies for such adverse impacts, which we are assuming
without accepting play a causal role in such adverse impacts. We did
not apply a quantitative discount when analyzing the modeling performed
for purposes of this final action. Nevertheless, it bears emphasis that
the projected impacts on GMST and GSLR trends do not translate directly
to adverse health and welfare impacts and do not account for additional
factors, including adaptation and mitigation factors, that would
necessarily inform such impacts. As discussed in section V.A of this
preamble, the analytical difficulties, uncertainties, and multiple
causal leaps involved in this exercise are themselves a reason to
conclude that CAA section 202(a)(1) does not encompass emissions that
can be said to lead to adverse health and welfare impacts only by
constructing a global air pollution framework.
Second, the elimination of GHG emissions from all new and existing
U.S. LD, MD, and HD vehicles substantially overestimates the impacts of
the EPA's GHG emission standards. The standards apply only to ``new''
vehicles and engines, and fleet turnover (i.e., the transition from
existing vehicles to new vehicles covered by the standards) generally
takes more than 20 years.\179\ The most recent GHG emission standards
finalized in 2024 phased in beginning in MY 2026 and increased in
stringency through MY 2032 and beyond, meaning the full emissions
reductions attributable to the standards would not be expected until
well after 2052. Moreover, despite being the most stringent to date,
the 2024 standards were projected to reduce GHG emissions by
approximately 50 percent as compared to the preexisting standards for
MY 2026 and beyond.\180\ The appropriate discount between the modeled
scenario (the elimination of all GHG emissions from vehicles) and the
reductions achieved in practice by EPA GHG emission standards (i.e.,
the difference between the scenario and the likely real-world scenario)
turns on a variety of factors that are difficult to predict, including
our regulatory decisions for MY 2032 and beyond, separate regulatory
influences, and changes to the underlying economics, technologies, and
consumer preferences. For illustrative purposes, we present below a
scenario in which EPA GHG emission standards would eliminate an
additional 50 percent of GHG emissions from LD, MD, and HD vehicles as
compared to the baseline.
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\179\ U.S. EPA. ``Population and Activity of Onroad Vehicles in
MOVES5'' EPA-420-R-24-019, November 2024.
\180\ For MY 2032 and beyond new motor vehicles, the EPA
projected that the 2024 GHG emission standards final rules would
result in a 50 percent reduction in new LD vehicle CO2
emissions, a 41 percent reduction in new MD vehicle CO2
emissions, and a 25-60 percent reduction in new HD vehicle
CO2 emissions (dependent on vehicle category). See 89 FR
27842, 27908-09 (Apr. 18, 2024); 89 FR 29440, 29451-52 (Apr. 22,
2024); 89 CFR 27914-915.
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Under the 50 percent reduction scenario, retaining a GHG emission
standards program for vehicles and engines would result in a 0.007
(0.005-0.009) [deg]C impact on projected GMST through 2050 and 0.019
(0.012-0.027) [deg]C impact on projected GMST through 2100. Retention
would result in a 0.05 (0.03-0.053) cm impact on projected GSLR from
2027 to 2050 and 0.7 (0.20-2.39) cm impact on projected GSLR from 2027
to 2100. Again, this is an illustrative scenario and a rough estimate
that pairs some analytic tools not intended for this purpose with other
tools in the literature. As such, it cannot be assumed to translate
with precision directly to specific adverse health or welfare impacts.
Note, however, that these figures are themselves likely an
overestimation of the actual predicted impact of GHG emission standards
over the relevant time horizon because this illustrative 50 percent
reduction scenario does not reflect what such standards would
realistically achieve given technical and statutory constraints.
Whether viewed in terms of the complete elimination scenario or the
illustrative 50 percent reduction scenario, these projections lead the
EPA to determine that GHG emission standards under CAA section
202(a)(1) have no material impact (i.e., beyond a de minimis level) on
the global climate change concerns relied upon in the Endangerment
Finding to justify regulation. This determination leads us to two
independent conclusions. First, as discussed in section V.A of this
preamble, the futility of GHG emission standards under CAA section
202(a)(1) further supports that the best reading of the statute does
not encompass global climate change concerns within the scope of the
``air pollution'' that Congress authorized and required the EPA to
address. And second, as discussed in this section below, the futility
of GHG emission standards under CAA section 202(a)(1) renders retaining
such standards unreasonable given the certain and immense costs and
other direct adverse impacts of the standards.
Under any reasonable understanding, the predicted impacts of
eliminating all U.S. GHG emissions from vehicles and engines on GMST
and GSLR are de minimis. Even without accounting for the difference
between total elimination under the modeled scenario and emission
control using GHG standards under the discounted scenario, the
predicted impacts through 2100 (0.013 [deg]C as shown in Table 5) are
below the
[[Page 7733]]
range of measurability for GMST and likewise for GSLR (1.4 cm as shown
in Table 7).\181\ Additionally, as stated previously, GMST variability
from 2016-2025 was 0.14 [deg]C, which is almost four times greater than
the GMST change estimated in 2100 from eliminating all U.S. vehicle and
engine GHG emissions.\182\
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\181\ See National Oceanic and Atmospheric Administration
(NOAA), National Centers for Environmental Information, Global
Surface Temperature Anomalies-Methodology and Uncertainty,
estimating uncertainty in annual global mean surface temperature of
approximately 0.05 [deg]C since 1950, increasing to
0.1-0.2 [deg]C in the late 19th Century. Available at
https://www.ncei.noaa.gov/access/monitoring/global-temperature-anomalies.
\182\ National Centers for Environmental Information, Climate at
a Glance. NOAAGlobalTemp. Available at https://ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/globe/land_ocean/tavg/ytd/12/1950-2025.
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Once the figures are reduced to reflect the potential impact of EPA
GHG emission standards, which only reduce, rather than eliminate, all
GHG emissions from vehicles and engines for the reasons discussed
above, the de minimis nature of the impact is even clearer. The reduced
impact is approximately one percent of the model-projected change in
GMST for 2050 and 2100.\183\ The reduced impact is much less than one
percent of the change in GSLR modeled for 2050 and 2100. As discussed
in section V.A of this preamble, Congress does not include de minimis
concerns in general statutory language, and agencies need not address
de minimis concerns where doing so would yield trivial value under the
statutory scheme.\184\ The general instruction in CAA section 202(a)(1)
to ``prescribe . . . standards'' for emissions that contribute to air
pollution which may reasonably be anticipated to endanger public health
or welfare does not override this background principle, and regulatory
agencies and courts have consistently viewed impacts of one percent as
de minimis and therefore not encompassed within general statutory
language.\185\
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\183\ For context, the Administrator relied in the Endangerment
Finding on predictions that global temperature would increase from
1990 to 2100 between 1.8 to 4.0 [deg]C. 74 FR 66519.
\184\ See, e.g., UARG, 573 U.S. at 333; Ala. Power, 636 F.2d at
360-61.
\185\ See, e.g., UARG, 573 U.S. at 333 (suggesting that an
appropriate de minimis level of stationary source GHG emissions
could be substantial in an absolute sense); EME Homer, 572 U.S. 489
(approving rule that did not require additional emissions reductions
from States that contributed less than one percent to nonattainment
in other States); In re Rail Freight Fuel Surcharge Antitrust
Litig., 934 F.3d 619, 625 (D.C. Cir. 2019) (applying benchmark of
five-to-six percent for the number of uninjured class members that
destroy predominance in class certification context); CareFirst of
Md., Inc. v. First Care, P.C., 434 F.3d 263, 268 (4th Cir. 2006)
(survey showing two percent consumer confusion de minimis in the
trademark context); Arent v. Shalala, 70 F.3d 610, 617 (D.C. Cir.
1995) (accepting 10 percent de minimis threshold in FDA compliance
regulation).
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Relevance to the best reading of CAA section 202(a)(1). In reaching
this determination, we recognize that CAA section 202(a)(1) authorizes
preventative regulation that need not fully ameliorate the identified
harms. But in discussing the statute's preventative nature, the EPA and
reviewing courts consistently understood that regulation must be
capable of having at least a material impact on the identified
danger.\186\ The background legal principles discussed in section V.A
of this preamble support this reading of the statutory standard.
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\186\ See, e.g., Ethyl Corp. v. EPA, 541 F.2d 1, 29-32 (D.C.
Cir. 1976) (en banc) (approving standards for lead content in
gasoline supported by finding that lead emissions from gasoline were
a ``significant source'' of total environmental exposure ``that was
particularly suited to ready reduction'').
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The futility determination reached in this final action is
different in kind from the policy arguments previously addressed in
Massachusetts and Coalition for Responsible Regulation, which focused
on the cost-benefit balance of potential regulatory responses and
general concerns about the most efficient way to regulate in response
to global climate change concerns. Rather, we conclude that CAA section
202(a)(1) requires that emission standards be capable of having a
material impact on the identified danger for the Administrator to
conclude that the emissions ``contribute'' to air pollution that may
``reasonably be anticipated'' to endanger public health and welfare. If
controlling or eliminating the emissions would not materially impact
the identified danger, the emissions do not ``contribute'' to the air
pollution. And because the emitted ``air pollutant'' and the ``air
pollution'' are defined in this context as the ``six well-mixed GHGs,''
the air pollution cannot ``reasonably be anticipated'' as endangering
health or welfare in the CAA section 202(a) context if controlling or
eliminating all vehicle and engine emissions would have no impact. Put
another way, the inability of GHG emission standards to have any
material impact demonstrates that GHG emissions from new vehicles and
engines do not contribute to air pollution that endangers public health
or welfare. That determination is relevant to the findings required by
CAA section 202(a)(1).
The EPA recognized in the Endangerment Finding that CAA section
202(a) incorporates de minimis principles, stating that the
contribution of motor vehicle and engine GHG emissions to the ``air
pollution'' must be more than trivial. See 74 FR 66506, 66509, 66542-
43. But we avoided consideration of this limitation in the remainder of
the analysis by severing the endangerment and contribution findings
from the analysis of responsive regulation. We asserted that requiring
the Agency to show that control measures ``would prevent at least a
substantial part of the danger'' would ``be an unworkable
interpretation, calling for EPA to project out the result of perhaps
not one, but even several, future rulemakings stretching over perhaps a
decade or decades.'' 74 FR 66507-08. We further asserted that
effectiveness would turn not only on CAA section 202(a) regulations,
but also on ``the larger context of the CAA and perhaps even the global
context'' based on our belief that all sources must ``do their part''
to avoid a collective action problem. 74 FR 66508. In this way, we
deferred to future agency action any consideration whether regulation
would have more than a de minimis impact. Upon reviewing multiple
rounds of CAA section 202(a)(1) GHG emission standard rulemakings
predicated on the Endangerment Finding, however, we acknowledge that
the EPA never meaningfully returned to the question. Rather, we focused
on estimates of GHG emission reductions and, in RIAs not relied upon to
justify the standards, attempts to monetize such reductions using SCC
methodology.\187\ That was not consistent with the best reading of the
statute, which provides that the proper focus is not on the emissions
themselves, but on the possible dangers to health or welfare.
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\187\ See, e.g., 89 FR 29440, 29675 (Apr. 22, 2024) (2024 HD GHG
Emission Standards Rule); 75 FR 25324 (May 7, 2010) (Tailpipe Rule).
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Emission standards for criteria pollutants and air toxics have
markedly different impacts, and a comparison to the GHG emission
standards is illustrative.\188\ Unlike the GHG emission standards, the
EPA's criteria pollutant and air toxic standards protect health and
welfare by reducing emissions of air pollutants that have direct
effects from local and regional exposure. Moreover, the standards
achieve health and welfare benefits without relying on further action
with respect to other sources (i.e., stationary sources) or
[[Page 7734]]
actions by other countries. Whether the EPA regulates criteria
pollutant and air toxic emissions from power plants, for example, the
CAA section 202(a) standards materially reduce the health and welfare
impacts. Importantly, the risk-reduction benefits of those standards
are material regardless whether other countries reduce emissions of the
same pollutants.\189\
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\188\ For example, approximately 45 percent of NOX,
less than 10 percent of VOCs, and less than 10 percent of
PM2.5 and PM10 in the United States come from
the transportation sector. See https://www.epa.gov/transportation-air-pollution-and-climate-change/smog-soot-and-other-air-pollution-transportation.
\189\ To note, we acknowledge that criteria air pollution does
come from other countries into the United States and the CAA allows
for discounting those emissions when determining compliance with the
NAAQS.
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Independent basis for repealing GHG emission standards. Separate
from the rescission of the Endangerment Finding, the EPA is finalizing
the futility rationale as a standalone basis for repealing the GHG
emission standards. Even if the CAA section 202(a)(1) authorized the
Endangerment Finding as a standalone decision, it would be unreasonable
and impermissible to retain a regulatory program that imposes immense
costs while providing no material value in furtherance of a legitimate
statutory objective. This alternative basis turns on the statutory
language in CAA section 202(a) more generally, including the cost
consideration requirements of CAA section 202(a)(2). As the Supreme
Court explained in Michigan, agencies are bound to consider cost unless
the statute expressly provides otherwise. Here, where the costs or
regulation are certain and immense but the health and welfare value of
regulation are uncertain and de minimis, it is unreasonable to maintain
the GHG emissions program. For further discussion, see additional
discussion in the sections of the preamble that follow and the Response
to Comments document.
2. Summary of Comments and Responses and Updates to the Final Action
In response to the proposal, the Agency received a number of
technical comments regarding the proposed futility basis, including
comments on the impacts of total U.S. GHG emissions and U.S. motor
vehicle GHG emissions to climate change effects. Multiple commenters
provided projected changes in global CO2 concentrations and
global surface temperature changes for the years 2050 and 2100 for a
range of modeled scenarios. These scenarios included modeled changes
from the elimination of all U.S. CO2, or elimination of all
U.S. power sector CO2 emissions (which the commenter
indicated was of similar magnitude to the emissions from motor
vehicles), or the elimination of all U.S. motor vehicle GHG emissions.
Other commenters cited to climate modeling the EPA included in the
light-duty vehicle GHG 2010 standard setting final rule. In general,
the commenters utilized the Model for the Assessment of Greenhouse Gas
Induced Climate Change (MAGICC) model, a model the EPA has used in the
past. While the scenarios were not identical to the modeling described
in section V.C.1 of this preamble which the EPA performed for this
final action,\190\ the EPA finds that in general commenters who
performed climate modeling projected changes in global surface
temperature impacts similar to the EPA's modeling. As discussed in
detail in section V.C.1 of this preamble, the EPA finds the modeled
projected impacts from the complete elimination of GHG emissions from
US on-road vehicles to be de minimis, and the impacts from potential
EPA GHG standards for U.S on-road vehicles, which would not result in a
complete elimination of GHG emissions, to be even smaller and thus also
de minimis. The Response to Comments document summarizes the comments
we received regarding climate modeling projections and our detailed
responses.
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\190\ See Memorandum to Docket EPA-HQ-OAR-2025-0194. ``Technical
Memo on: Temperature, CO2 Concentration, and Sea Level
Rise Impacts of Greenhouse Gas Emissions from U.S. Motor Vehicles.''
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VI. Additional Proposed Bases for Rescission of the Endangerment
Finding and Repeal of GHG Emission Standards the Agency Is Not
Finalizing at This Time
In this section, the EPA discusses the alternative bases for
rescinding the 2009 Endangerment Finding and repealing associated new
motor vehicle and engine GHG emission standards that we presented for
comment at proposal but are not finalizing at this time. The discussion
below is provided in the interests of transparency and public
engagement and should not be understood as presenting any views or
conclusions related to the bases for this final action set out in
section V of this preamble. As explained below and noted where
appropriate in the Response to Comments document, the comments received
on these alternative proposed bases are out of scope of this final
action given our predicate conclusions that we lacked statutory
authority to issue the Endangerment Finding and cannot retain or
prescribe GHG emission standards for new motor vehicles and engines in
response to global climate change concerns under CAA section 202(a)(1)
and, separately, that the futility of GHG emission standards in
addressing global climate change concerns renders it unreasonable to
retain the standards.
A. Climate Science Alternative Basis
In the proposal, the EPA described an alternative rationale for
rescinding the 2009 Endangerment Finding and repealing associated GHG
emission standards for new motor vehicles and engines. Under that
alternative proposed basis, the EPA stated that even if CAA section
202(a)(1) could be read to authorize regulation of GHG emissions from
new motor vehicles and engines in response to global climate change
concerns, the Administrator would exercise his judgement differently
today in light of intervening scientific developments and limitations
and uncertainties in the record for the Endangerment Finding. Although
the Administrator continues to harbor concerns regarding the scientific
determinations underlying the Endangerment Finding, the EPA has decided
not to finalize this scientific alternative rationale at this time. As
explained in section V of this preamble, the EPA is rescinding the
Endangerment Finding based on the best reading of CAA section
202(a)(1), under which the EPA concludes that Congress did not
authorize the Agency to regulate GHG emissions from new motor vehicles
and engines in response to global climate change, and, separately, is
repealing the GHG emission standards for the additional reason that
futility renders it unreasonable to retain the standards. These legal
conclusions are sufficient to support rescission of the Endangerment
Finding and repeal of the related GHG emission standards without the
additional scientific basis set out at proposal.
As the EPA does not adopt or rely on the proposed scientific
alternative rationale in this final action, the Agency does not need
to, and is not legally required to, respond to comments that address
that unfinalized alternative. Nevertheless, in the interest of
transparency and to assist the public in understanding the outcome of
this rulemaking, the EPA provides the following summary of major themes
raised by commenters regarding the proposed scientific alternative
rationale. The EPA offers this summary for informational purposes only.
The EPA does not (and, given the bases on which it finalizes this
action, cannot) in this rulemaking resolve the underlying scientific
debates described below, does not issue a new or revised scientific
determination under CAA section 202(a)(1), and does not adopt or
endorse any particular assessment, study, or
[[Page 7735]]
comment as a statement of the Administrator's scientific judgement. The
descriptions and responses that follow explain how the EPA has
considered the comments in deciding not to finalize the scientific
alternative rationale, but they are not necessary to, and do not form
an independent basis for, the legal conclusions on which this final
action rests. In light of the conclusions adopted in this final action
with respect to the best reading of CAA section 202(a)(1) and the EPA's
authority thereunder, we cannot resolve remaining uncertainty regarding
these issues in this regulatory context.
Comments Asking the EPA to Characterize Whether the Science of
Climate Change is ``Settled'': Several commenters asked the EPA to
state more clearly whether the Agency views the science of climate
change as settled or unsettled. Some commenters urged the EPA to state
that climate science remains unsettled, and that significant
disagreement persists on key issues related to climate sensitivity,
extreme events, and projected impacts. Others urged the EPA to state
that the science is settled to the extent relevant to the Endangerment
Finding and pointed to statements by scientific organizations and
assessments that describe strong or ``overwhelming'' consensus
regarding the reality of climate change and the influence of human
activities.
Response: The Administrator continues to harbor concerns regarding
the scientific analysis underpinning the Endangerment Finding. A core
tenet of empirical science is that it is falsifiable--that it can
always be updated or changed in light of new evidence. The scientific
record contains analyses that regularly reveal new uncertainties,
challenge old assumptions, propose new interpretations of evidence, and
reach differing conclusions. Analyses also explicitly question the
weight that policymakers should place on particular projections or
impact estimates, due in part to this uncertainty. Commenters generally
recognized that relevant data is being collected on a continuing basis
and analyzed against prior projections but drew very different
conclusions from such data. Similarly, commenters drew very different
conclusions from statements by scientific organizations that the
consensus on these issues is strong or ``overwhelming,'' which certain
commenters took as evidence of certainty and others took as reason to
question the underlying data and analyses. We recognize the importance
of these issues and the importance placed on them by many commenters.
In light of the bases adopted for this final action, however, the EPA
lacks authority to resolve these issues here for regulatory purposes
under CAA section 202(a)(1).
Comments Asserting That Intervening Science No Longer Supports the
2009 Endangerment Finding: Some commenters supported the proposal's
description of scientific uncertainty and agreed that the current
record does not support the assumptions and conclusions of the
Endangerment Finding. These commenters argued that experience since
2009 revealed limitations in global and regional climate models,
including differences between model projections and certain
observational records and reanalysis in specific regions or time
periods. These commenters stated that projections of temperature
change, sea level rise, and some categories of extreme events span wide
ranges, and they contend that those ranges reduce confidence in the
magnitude and timing of risks that the Endangerment Finding associated
with anthropogenic GHG emissions.
Additionally, one commenter, for example, provides that there is
significant bias in climate methodology that was relied upon in the
Endangerment Finding. That commenter specifically provides that
``mainstream climate research'' has relied on a triply biased
methodology that runs overheated models with inflated emission
scenarios and ignores or minimized adaptation. The result, according to
that commenter, is exaggerating the physical impacts of GHG emissions
and harmfulness of such impacts.
Commenters also focused on causation and scale. These commenters
emphasized that climate change is a global phenomenon and argued that
GHG emissions from U.S. mobile sources represent a de minimis share of
global GHG emissions. In their view, the available science does not
support a sufficiently direct and quantifiable link between incremental
changes in GHG emissions from U.S. vehicles and specific public health
or welfare harms in the U.S. These commenters claimed that the
Endangerment Finding relied too heavily on modeled scenarios and
synthesis reports and did not fully account for natural variability,
observational uncertainty, and adaptive capacity.
Response: The EPA acknowledges that some commenters view
intervening scientific literature and observational experience as
weakening the basis they believe underlay the Endangerment Finding. We
also acknowledge that questions related to model performance, regional
patterns of change, internal variability, and the magnitude of
projected impacts will continue to be examined. As provided in this
section, the existence of these differing approaches and viewpoints
confirms that climate science, including climate-impact assessments,
remains an active field of research and assessment rather than a closed
or static record. Researchers continue to refine observational
datasets, develop and evaluate models, improve methods for detecting
and attributing observed changes, and explore alternative ways to
characterize uncertainty and risk. Assessment bodies periodically
revisit and synthesize this evolving literature, and authors continue
to publish analyses that emphasize different aspects of the evidence.
The EPA therefore views the scientific record as dynamic and subject to
ongoing refinement, and the Agency does not, in this final action,
attempt to resolve the scientific or methodological debates reflected
in that record. In light of the bases adopted for this final action,
the EPA lacks authority to resolve these issues here for regulatory
purposes under CAA section 202(a)(1).
Comments Asserting That Scientific Assessments Since 2009 Have
Strengthened the Basis for the 2009 Endangerment Finding: Other
commenters disagreed with the scientific discussion in the proposal and
with the claim that intervening science no longer supports the
Endangerment Finding. These commenters emphasized that, in their view,
major assessment reports completed since 2009, including the
Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment
Report and the Fifth National Climate Assessment (NCA5), describe that
the climate system has warmed; that human activities, particularly GHG
emissions, have contributed substantially to observed warming since the
mid-twentieth century; and that climate change already affects a wide
range of physical, ecological, social, and economic outcomes.
Commenters pointed to NCA5's finding that climate change is affecting
every U.S. region and multiple sectors, including health, agriculture,
infrastructure, and ecosystems, and that risks increase with additional
emissions. Commenters also cited reports from the National Academies of
Sciences (NAS), such as Climate Change: Evidence and Causes, and a 2025
review of GHG emissions and U.S. climate, health, and welfare which
they describe as concluding that multiple lines of evidence link
anthropogenic GHG emissions to observed warming and associated risks.
[[Page 7736]]
These commenters argued that, taken together, these assessments
indicate that the scientific basis for concluding that GHG emissions
may reasonably be anticipated to endanger public health and welfare has
strengthened since 2009, not weakened. These commenters contended that
the proposal downplayed or mischaracterized these assessments by
emphasizing selected uncertainties without giving sufficient weight to
their central conclusions.
Response: The EPA acknowledges that many commenters relied on IPCC,
NCA5, and NAS reports to argue that mainstream scientific assessments
continue to support and, in their view, reinforce the types of
conclusions that informed the Endangerment Finding. The EPA further
acknowledges that these assessments describe several conclusions,
including that human influence has warmed the climate system and that
climate change poses a range of risks to people and the environment.
At the same time, the EPA recognizes that the scientific record
does not consist of a single set of results, but instead reflects a
range of analyses that place different weight on particular datasets,
models, and impact estimates. Some studies and assessments rely more
heavily on global climate model ensembles and long-term series of
surface temperature, ocean heat content, and sea level, while others
emphasize satellite records, reanalysis products, and shorter-term
regional observations. Different authors make different methodological
choices about how to treat internal climate variability, combine
observational datasets, and evaluate model performance at global,
regional, or local scales.
The literature includes a range of results with varied degrees of
confidence regarding probabilistic outcomes, which in turn may affect
the weight decision makers should place in particular projections and
in the quantification of specific climate-related risks. Similarly,
impact analyses and integrated assessments apply different assumptions
when translating projected physical changes into estimates of effects
on health, agriculture, infrastructure, ecosystems, and the broader
economy. Those analyses vary in their assumptions about population,
economic growth, land use, technical change, adaptation, and behavioral
responses. Some studies emphasize the potential for adaptation and
innovation to reduce harms; others highlight the potential for
compounding effects, distributional consequences, or low-probability,
high-impact outcomes. These choices can lead to different estimates of
the magnitude, timing, and regional distribution of impacts, even when
starting from similar underlying physical projections.
Comments on Scientific Uncertainty, Assumptions, and What Remains
Unknown: Commenters on both sides discussed the nature and implications
of scientific uncertainty. Commenters who supported rescission on
scientific grounds highlighted uncertainty in estimates of climate
sensitivity, the representation of cloud and aerosol processes,
regional precipitation changes, and how the frequency and intensity of
specific extreme events may change in particular locations. These
commenters argued that differences among observational datasets and
model ensembles at certain scales make it difficult, in their view, to
quantify reliably the magnitude of future climate change and associated
impacts.
Other commenters agreed that uncertainties exist but emphasized
that major assessments explicitly acknowledge and characterize these
uncertainties while still reaching robust conclusions about several
aspects of climate change. These commenters noted that the Global
Change Research Act directs national assessments to discuss both
scientific findings and scientific uncertainties, and argued that
uncertainty often relates to the size, timing, or regional distribution
of projected changes rather than the direction of change or the
fundamental influence of GHG emissions on the climate system.
Commenters from multiple perspectives also discussed uncertainties
and assumptions in the translation of physical climate changes to
quantified health and welfare outcomes. These commenters observed that
impact assessments must make assumptions about future population and
economic growth, land use, technology, adaptation measures, and human
behavior. Some commenters argued that such assumptions may overstate
risks by underestimated adaptation and innovation. Others argued that
the same assumptions may understate risks because they may not fully
capture low-probability, high-impact outcomes, compounding effects, or
distributional consequences.
Response: The EPA agrees that significant uncertain assumptions
remain in the scientific record related to climate change and its
impacts. Climate and impact modeling necessarily involve choices about
emissions scenarios, socioeconomic pathways, and adaptation responses,
as well as assumptions about processes within the climate system
itself. The EPA also recognizes that different scientific bodies and
authors may draw different inferences from the same underlying data
when weighing these uncertainties. Major assessments, such as IPCC and
NCA5, describe many of these uncertainties and present ranges of
projected outcomes, while still expressing confidence in certain broad
findings. Other analyses highlighted by commenters place relatively
greater emphasis on the limits of current models and on the difficulty
of quantifying net impacts.
Comments on Ongoing Scientific Debate and Future Assessments,
Including a Possible 6th National Climate Assessment (NCA6): Several
commenters asked the EPA to recognize explicitly that scientific
research and debate about climate change will continue, regardless of
the outcome of this rulemaking. These commenters pointed to ongoing
work in universities, Federal and state agencies, and international
institutions, and noted that the U.S. has historically produced
periodic NCAs under the Global Change Research Act.
Some commenters referenced recent developments affecting Federal
climate assessment activities, including actions that have affected
contributors and online access to materials related to a future NCA6.
These commenters argued that even if institutional arrangements change,
scientific work on climate change will continue in peer reviewed
literature and independent synthesis efforts. Some commenters urged the
EPA to defer any change to the Endangerment Finding until after any new
national or international assessment, while others argued that the
existence of continuing debate and evolving research supports a
decision not to rely on the Endangerment Finding.
In response, the EPA understands that scientific research and
debate about climate change will continue during and after this
Administration. Researchers will continue to publish new observations,
attribution studies, model evaluations, and impact assessments.
Domestic and international bodies may undertake additional synthesis
efforts, including any future work related to a NCA6 or comparable
report.
Comments on the EPA's use of the Proposed Scientific Alternative:
Some commenters who opposed the proposed scientific alternative
requested that if the EPA decides not to finalize that rationale, the
Agency should make clear that the Agency is not relying on specific
scientific critiques as a necessary or independent basis for rescinding
the Endangerment Finding or
[[Page 7737]]
repealing vehicle GHG standards. These commenters expressed concern
that references in the proposal could be misinterpreted as a new
negative scientific judgement about climate change and its impacts.
These commenters asked the EPA to clarify that the Agency is not
issuing a new scientific determination under CAA section 202(a). Other
commenters, including some who supported rescission on scientific
grounds, urged the EPA to retain a version of the scientific
alternative rationale in the final action to signal ongoing concerns
about the treatment of uncertainty, model performance, and global
versus domestic contributions to climate risk. These commenters argued
that such a discussion would provide context for any future Agency
considerations of climate-related issues, even if the EPA based this
particular decision primarily on legal grounds.
Response: The EPA has considered these comments and, in this final
action, is not finalizing the alternative climate science rationale and
is not finalizing new findings by the Administrator with respect to
global climate change concerns under CAA section 202(a)(1). The EPA
does not rely on any specific critique of climate science as a
necessary justification for this action. Given our conclusion that we
lack legal authority to regulate in response to global climate change
concerns under CAA section 202(a)(1), it would be unnecessary and
inappropriate to resolve such questions in this regulatory context. The
EPA includes this section to summarize major scientific themes
commenters raised and to acknowledge that scientific research and
debate about climate change will continue. This discussion does not
endorse or reject any particular assessment, study, or comment letter
in the docket with respect to assertions regarding global climate
change science and has limited its responses to the bases being
finalized in this final action. The EPA's conclusion in this final
action is limited to the legal determination that CAA section 202(a)
does not provide the authority to regulate GHG emissions from new motor
vehicles or new motor vehicle engines for the purpose of addressing
global climate change concerns, irrespective of how ongoing scientific
debates are ultimately resolved.
B. There Is No Requisite Technology for Light- and Medium-Duty Vehicles
That Meaningfully Addresses the Identified Dangers of the Six ``Well-
Mixed'' GHGs
As stated in section V.C of this preamble, even if all GHG
emissions were eliminated from all LD, MD and HD vehicles and engines,
it would have a de minimis impact on public health or welfare.
Therefore, there is no requisite control technology for LD and MD
vehicles and engines that would meaningfully address the potential
public health or welfare impacts since there is no technology that
would completely eliminate all GHG emissions from vehicles.
However, due to the EPA's lack of authority under CAA section
202(a), the EPA does not believe that it is necessary to finalize this
alternative basis for repeal. To note, as it relates to setting
standards under CAA section 202(a)(2), the EPA must take into account
requisite technology, giving appropriate consideration to the cost of
compliance.
We therefore believe it is more appropriate to consider whether
there is any ``requisite technology'' that could meet the statutory
requirements when establishing standards than under this regulatory
action.
C. There Is No Requisite Technology for Heavy-Duty Vehicles That
Addresses the Identified Dangers of the Six ``Well-Mixed'' GHGs
As stated in section V.C of this preamble, even if all GHG
emissions were eliminated from all LD, MD and HD vehicles and engines,
it would have a de minimis impact on public health or welfare.
Therefore, there is no requisite control technology for HD vehicles and
engines that would meaningfully address the potential public health or
welfare impacts since there is no technology that would completely
eliminate all GHG emissions from vehicles.
However, due to the EPA's lack of authority under CAA section
202(a), the EPA does not believe that it is necessary to finalize this
alternative basis for repeal. We therefore believe it is more
appropriate to consider whether there is any ``requisite technology''
that could meet the statutory requirements when establishing standards
than under this regulatory action.
D. More Expensive New Vehicles Prevent Americans From Purchasing New
Vehicles That Are More Efficient, Safer, and Emit Fewer GHGs
In the proposal, the Agency described alternative bases that the
Administrator could consider as rationale for the proposed repeal of
the GHG standards. One of them was the negative impact that higher
vehicle prices (from the GHG standards) may have on delaying the
purchase of safer and lower emitting vehicles. In the proposal, the
Agency noted that complying with GHG emission standards often requires
manufacturers to design and install new and more expensive
technologies, thereby increasing the price of new vehicles and reducing
consumer demand. More expensive new vehicles are cost prohibitive for
some consumers, and those consumers are likely to turn to the used
vehicle market or continue using an older vehicle rather than purchase
a new vehicle. The Agency stated in the proposal that all other things
being equal, an increase in the price of new vehicles can result in
consumers keeping their vehicles for longer periods, delaying the
purchase of new vehicles, and decreasing the rate at which old vehicles
in the national fleet are replaced by new vehicles (i.e., fleet
turnover). Contrary to the goals of the EPA's GHG emission standards
and the intended purpose of CAA section 202(a), a delay in fleet
turnover can negatively impact air quality because older vehicles tend
to emit higher levels of air pollutants, including criteria pollutants
and hazardous air pollutants, regulated by the EPA.\191\ Slowing fleet
turnover is of particular concern with respect to the EPA's 2024 GHG
Emission Standards Rules because of the large increase in vehicle
technology costs which will likely lead to large increases in purchase
prices, and the impact battery electric and fuel cell vehicle
technologies will have on purchasing decisions of consumers (for light-
, medium-, and heavy-duty vehicle buyers). Increased prices and some
consumers rejecting battery electric and fuel cell vehicle technologies
may lead consumers to hold on to their existing vehicles longer.
Vehicles are more likely to emit less air pollution with each
subsequent model year because of improvements in technology, ordinary
wear and tear that decreases the effectiveness of installed technology,
and greater stringency in more recent regulations for criteria
pollutants and hazardous air pollutants.\192\ The Agency requested
comment on this proposed alternative basis for the repeal of the
vehicle and engine GHG standards.
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\191\ A discussion of the impact of higher vehicle prices on
slowing fleet turnover and thus increasing emissions can be found at
85 FR 24186 and 25039.
\192\ See 90 FR 36313.
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The Agency notes that since the publication of the EPA proposal,
NHTSA issued a proposal to change the CAFE standards for certain model
years of vehicles after determining that previous rulemakings
inappropriately considered alternative fuel technologies and the
availability of compliance credits, which is prohibited pursuant to 49
U.S.C. 32902(h). In their proposal,
[[Page 7738]]
NHTSA evaluated its statutory factors in light of current circumstances
and tentatively concluded that the existing standards exceed those that
are maximum feasible. In addition, NHTSA conducted detailed modeling of
the impact of various levels of fuel economy standards on new vehicle
purchases and the impact on the in-use vehicle fleet.\193\ NHTSA's
proposal finds that more stringent fuel economy standards lead to
higher vehicle prices, which in turn reduce vehicle fleet
turnover.\194\ NHTSA also finds that newer vehicles are safer than
older vehicles (both for the driver/occupants of the newer vehicles and
for safety of the in-use fleet overall). NHTSA also finds that newer
vehicles generally emit lower emissions of certain criteria pollutants,
depending upon the model year of the vehicle. In addition, in their
proposal, NHTSA evaluated its statutory factors in light of current
circumstances and tentatively concluded that the existing standards
exceed those that are maximum feasible. The Agency received substantial
supportive and adverse comments on this proposed alternative rationale
for repeal of the GHG standards. Several comments included technical
assessments and modeling to support the commenters' views.
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\193\ National Highway Traffic Safety Administration. ``Draft
Technical Support Document The Safer Affordable Fuel-Efficient
(SAFE) Vehicles Rule III for Model Years 2022 to 2031 Passenger Cars
and Light Trucks.'' December 2025. Chapter 4.3.
\194\ A discussion of the impact of higher vehicle prices on
slowing fleet turnover can be found at 85 FR 24626 (Apr. 30, 2020).
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As discussed elsewhere in this preamble, the Agency is repealing
the GHG standards because we do not have authority to establish such
standards under the CAA. The EPA is not basing the repeal on the
proposed alternative rationale described in this section (section VI.D
of this preamble). For this reason, the Agency has not responded to the
comments received on this alternative rationale from the proposal.
Nevertheless, the Agency does believe that when establishing or
revising emission standards under CAA section 202(a), the Administrator
may consider the impacts of emission standards on safety, and in some
cases is required to do so, such as standards established under CAA
section 202(a)(3)(A).
VII. Repeal of New Motor Vehicle and Engine GHG Emission Standards
As discussed in sections III, IV, and VI of this preamble, the EPA
is repealing all GHG emission standards for LD vehicles, MD vehicles,
HD vehicles, and HD engines. This includes emission standards for the
subset of four of the six ``well-mixed GHGs'' whose elevated
concentrations in the upper atmosphere the Endangerment Finding
identified as the ``air pollution'' in question that are actually
emitted by such vehicles and engines--CO2, N2O,
methane, and HFCs--as well as the compliance provisions for the GHG
standards. These changes apply to all MYs of vehicles and engines,
including MYs that have completed manufacture prior to the effective
date of the final action.
This final action increases flexibility for vehicle manufacturers.
Manufacturers will have no vehicle technology-mix constraints that
arise from the EPA GHG standards and will be free to produce a range of
technologies, including gasoline, diesel, alternative fuels, and plug-
in electric vehicles. Thus, we do not anticipate material compliance
difficulties on the part of manufacturers in response to this final
action.
In section VII.A of this preamble, we discuss the anticipated
impacts of repealing GHG emission standards under CAA section 202(a)(1)
on the overall regulatory scheme for parties currently subject to the
standards. As explained in this preamble section and elsewhere in this
preamble, we did not reopen for comment or substantively revise any
emission standards for criteria pollutants or hazardous air pollutants,
nor did we reopen or substantively revise any regulatory provisions
related to NHTSA's CAFE standards or the EPA's role in administering
EPCA and EISA. This final action also does not impact Federal
preemption for motor vehicle and engine emission standards under CAA
section 209(a) or under EPCA and EISA, including with respect to GHGs.
Regardless, whether we prescribe standards for GHG emissions from new
motor vehicles or engines, CAA section 209(a) continues to apply by its
own force to preempt State laws, regulations, and causes of action that
adopt or attempt to enforce any standard relating to the control of
emissions from new motor vehicles or engines.
In section VII.B of this preamble, we describe regulatory
amendments related to the LD and MD vehicle program. In section VII.C
of this preamble, we describe regulatory amendments related to the HD
engine and vehicle program. A memorandum submitted to the docket
includes redline text highlighting changes to the regulations.\195\
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\195\ Memorandum to Docket EPA-HQ-OAR-2025-0194, ``Redline
Version of EPA's Final Regulations for the Rescission of the
Greenhouse Gas Endangerment Finding and Motor Vehicle Greenhouse Gas
Emission Standards Under the Clean Air Act.'' February 2026.
---------------------------------------------------------------------------
The EPA's engine and vehicle programs are codified in Title 40 of
the CFR. Specifically, the standard-setting parts for light- and
medium-duty vehicles are located in 40 CFR part 85 and 86. The
standard-setting part for HD engines is located in 40 CFR part 1036 and
the standard-setting part for HD vehicles is 40 CFR part 1037. Each
standard-setting part includes regulations describing emission
standards and related requirements and compliance provisions for
certifying engines or vehicles. Consistent with the proposed rule and
explained in this preamble section and elsewhere in this preamble, the
EPA is retaining measurement procedures, reporting requirements, and
credit provisions for the LD program necessary for demonstrating
compliance with NHTSA's CAFE standards and the EPA's fuel economy
labeling program to meet our statutory obligations under EPCA and EISA.
In response to comments on the proposed rule, we are revising the
proposed approach for HD engines and vehicles subject to NHTSA's fuel-
consumption standards to similarly retain measurement procedures and
reporting requirements that are necessary for demonstrating compliance
with NHTSA's standards.
Further, as explained in this section and elsewhere in this
preamble, we did not reopen for comment and are not substantively
revising emission standards or compliance provisions related to
criteria pollutant exhaust emissions (i.e., NOX, HC, PM, and
CO), air toxic emissions, or evaporative and refueling emissions.\196\
We may consider those issues, as appropriate, in future rulemakings.
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\196\ In this rulemaking, NOX, HC, PM, and CO are
sometimes described collectively as ``criteria pollutants'' because
they are either criteria pollutants under the CAA or precursors to
the criteria pollutants ozone and PM.
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A. Scope and Impacts of Repealing the GHG Emission Standards
The repeal in this final action is limited to the regulatory
provisions for GHG emission standards found in 40 CFR parts 85, 86,
1036, and 1037, with minor conforming adjustments to unrelated emission
standards for new motor vehicles and engines in 40 CFR parts 600 and
1039. As detailed in sections VII.B and VII.C of this preamble, this
final action does not revise emission standards for criteria pollutants
or air toxics. The EPA may reconsider and propose to revise the
regulatory provisions for those programs in a separate rulemaking
action.
[[Page 7739]]
Similarly, we did not reopen for comment or propose to revise
regulatory provisions necessary for NHTSA's CAFE standards or the EPA's
co-administration of EPCA and EISA.
For this reason, the repealed provisions in this final action do
not impact Federal preemption under EPCA, as amended by EISA, related
to fuel economy standards. EPCA provides that when ``an average fuel
economy standard prescribed under this chapter is in effect, a state or
a political subdivision of a state may not adopt or enforce a law or
regulation related to fuel economy standards or average fuel economy
standards for automobiles covered by an average fuel economy standard
under this chapter'' \197\ unless the standards are identical or apply
only to vehicles obtained for the use of the state or political
subdivision.\198\ We reiterate that the EPA did not reopen this issue
in this rulemaking, as we did not propose to revise regulatory
provisions necessary for NHTSA's CAFE standards or the EPA's co-
administration of EPCA and EISA. In providing this information for
better clarity on the scope of the final action, the EPA notes that we
are not here ``undertak[ing] a serious, substantive reconsideration of
the existing'' position. Growth Energy v. EPA, 5 F.4th 1, 21 (D.C. Cir.
2021).
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\197\ 49 U.S.C. 32919(a).
\198\ 49 U.S.C. 32919(b)-(c).
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The repealed provisions in this final action also do not impact
Federal preemption under CAA section 209(a), which provides that ``[n]o
State or any political subdivision thereof shall adopt or attempt to
enforce any standard relating to the control of emissions from new
motor vehicles or new motor vehicle engines subject to this part,''
including ``certification,'' ``inspection'' or ``approval''
requirements ``relating to the control of emissions from'' such
vehicles or engines.\199\ Because new motor vehicles and engines that
have been subject to GHG emission standards remain subject to Title II
of the CAA, the statute would by its own force continue to preempt
``any'' State or local law, regulation, or cause of action that adopts
or attempts to enforce ``any standard relating to the control of
emissions.'' Relatedly, the CAA continues to preempt Federal common-law
claims for vehicle and engine emissions because Congress adopted a
standard for when such emissions rise to the level of regulatory
concern and ``delegated to EPA the decision whether and how to
regulate'' such emissions. Am. Elec. Power, 564 U.S. at 426. The CAA
also continues to preempt state common-law claims and statutes that
seek to regulate out-of-state emissions, independently of CAA section
209(a)'s express preemption provision for mobile-source emissions. See
City of New York v. Chevron Corp., 993 F.3d 81, 98-100 (2d Cir. 2021);
cf. Int'l Paper Co. v. Ouellette, 479 U.S. 481, 492 (1987). We retain
our authority to prescribe emission standards for any air pollutant
that, in the Administrator's judgment, causes or contributes to air
pollution that may reasonably be anticipated to endanger public health
or welfare. See the Response to Comments document for more detailed
comment summaries and responses.
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\199\ 42 U.S.C. 7543(a).
---------------------------------------------------------------------------
The EPA's engine and vehicle programs are codified in Title 40 of
the CFR. Specifically, the standard-setting parts for light- and
medium-duty vehicles are located in 40 CFR parts 85 and 86. The
standard-setting part for HD engines is located in 40 CFR part 1036 and
the standard-setting part for HD vehicles is 40 CFR part 1037. Each
standard-setting part includes regulations describing emission
standards and related requirements and compliance provisions for
certifying engines or vehicles.
B. Light- and Medium-Duty Vehicle GHG Program
Section VII.B.1 of this preamble provides background on the EPA's
LD and MD vehicle GHG emission programs. In general, through a series
of rulemakings beginning with MY 2010 for LD vehicles and MY 2014 for
MD vehicles, the EPA increased the stringency of the GHG standards for
these vehicles over time, in particular the CO2 standard.
The remainder of section VII.B of this preamble summarizes the comments
received, and describes the changes to the LD and MD vehicle GHG
regulations after considering those comments.
1. Background on the Light- and Medium-Duty Vehicle GHG Program
In 2010, the EPA relied on the Endangerment Finding to adopt the
first GHG emission standards for passenger cars and light trucks for
MYs 2012 through 2016 in a joint rulemaking with NHTSA.\200\ In 2012,
the EPA and NHTSA adopted another set of GHG standards (issued by the
EPA) and fuel economy standards (issued by NHTSA) for passenger cars
and light trucks for MYs 2017 and later in a joint rulemaking.\201\ In
2020, the EPA and NHTSA revised the standards that had previously been
adopted and extended them for MYs 2021 through 2026.\202\ In 2021, we
further revised GHG standards for passenger cars and light trucks for
MYs 2023 through 2026.\203\ For MD vehicles, we initially adopted GHG
standards as part of the Phase 1 and Phase 2 HD GHG standards. In 2024,
we adopted new standards for passenger cars, light trucks, and MD
vehicles starting in MY 2027, effectively combining standards that had
previously been maintained separately.\204\
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\200\ 75 FR 25324 (May 7, 2010).
\201\ 77 FR 62624 (Oct. 15, 2012).
\202\ 85 FR 24174 (Apr. 30, 2020).
\203\ 86 FR 74434 (Dec. 30, 2021).
\204\ 89 FR 27842 (Apr. 18, 2024).
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The EPA has also taken various actions to comply with statutory
obligations under EPCA and EISA. Enacted in 1975, EPCA requires NHTSA
to establish a regulatory program for motor vehicle fuel economy (now
known as CAFE standards) and requires the EPA to establish measurement
procedures, data collection procedures, and rules for calculating
average fuel economy values in support of NHTSA's CAFE standards. In
2007, Congress amended EPCA by enacting EISA, which required continuing
increases in the stringency of CAFE standards for passenger cars and
light trucks through MY 2020. EISA also authorized new fuel consumption
standards for MD vehicles and HD engines and vehicles.\205\ Those
standards, and the EPA's HD engine and vehicle GHG programs, are
detailed in section VII.C of this preamble.
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\205\ 49 U.S.C. 32902(k).
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To comply with EPCA and EISA, the EPA adopted regulations for fuel
economy measurements, calculations, and reporting under 40 CFR part
600. The regulation at 40 CFR part 600 now includes additional
provisions for measuring, calculating, and reporting fuel consumption
values for MD vehicles. This regulatory structure was designed to
maximize efficiency within the Federal government and minimize the
burden on the engine and vehicle manufacturers by centralizing data
submission. We share information with NHTSA as needed to support
implementation of NHTSA's fuel economy and consumption standards.
2. Summary of Comments and Updates to the Light- and Medium-Duty
Programs
Most comments related to GHG standards for LD and MD vehicles were
focused on the proposed rescission of the Endangerment Finding and
repeal of the GHG standards. Manufacturers suggested in comments that
the EPA establish or determine that the model
[[Page 7740]]
year 2027 and later GHG standards in 40 CFR 86.1818-12 and 86.1819-14
are not appropriate, even if those standards are removed in this final
action. The commenters suggested making such a determination to prevent
future rulemaking action that would simply restore the standards as
originally adopted. The EPA is removing the GHG emission standards for
the reasons described in sections II, IV, and VI of this preamble.
Because we are finalizing the conclusion that the EPA lacks authority
to prescribe GHG emission standards in response to global climate
change concerns under CAA section 202(a)(1), we are not putting in
place alternative GHG emission standards.
Commenters also correctly identified several additional amendments
to remove detailed regulatory provisions that become obsolete in the
absence of GHG standards. We have amended the regulation to incorporate
the suggested amendments as noted in the following section VII.B.3 of
this preamble. See the Response to Comments document for more detailed
summaries of and responses to comments related to specific LD and MD
vehicle GHG regulations.
3. Changes to the Light- and Medium-Duty Vehicle GHG Regulations
The EPA's LD and MD vehicle emission regulations are spread across
three CFR parts. 40 CFR part 85 includes various general compliance
provisions for both criteria pollutant and GHG emissions. Many of those
criteria pollutant provisions apply equally to highway motorcycles (but
not for GHG emissions, as there are no EPA GHG requirements under 40
CFR part 85 for motorcycles). 40 CFR part 86 includes emission
standards and certification provisions for both criteria pollutant and
GHG emissions. 40 CFR part 600 includes measurement and reporting
procedures related to fuel economy and GHG standards and to fuel
economy labeling.
In the following preamble subsections, we describe the changes in
this final action to remove and amend specific portions of each of
these regulatory parts. The general approach is to remove the MY 2012
and later GHG emission standards for passenger cars and light trucks
and the MY 2014 and later GHG emission standards for MD vehicles. We
are also removing the testing and reporting requirements associated
with the GHG emission standards. In keeping with our obligations under
EPCA, as noted in section VII.B.1 of this preamble, we are not removing
the testing and reporting requirements related to CAFE standards for
passenger cars and light trucks. We are similarly preserving the
testing and reporting provisions related to NHTSA's fuel-consumption
standards for MD vehicles.
a. 40 CFR Part 85--Compliance Provisions for Light- and Medium-Duty
Vehicles
This final action amends 40 CFR part 85 to remove all references to
GHG emission standards and related provisions while retaining
provisions that support our criteria pollutant emission program. In
this preamble subsection, we describe several amendments that are
necessary to remove GHG-related provisions from 40 CFR part 85 while
ensuring that criteria pollutant emission standards are not
substantively impacted. Table 8 provides a summary of amendments to 40
CFR part 85.
[GRAPHIC] [TIFF OMITTED] TR18FE26.010
The regulations at 40 CFR part 85, subpart F, provide an exemption
from the general tampering prohibition for clean alternative fuel
conversions. Specifically, the regulations describe how anyone
modifying an in-use vehicle to run a different fuel can demonstrate
that the fuel conversion maintains a level of emission control that
qualifies them for an exemption from the tampering prohibition. This
exemption generally allows for modifying vehicles already certified to
emission standards in a way that does not cause the modified vehicle to
exceed the emission standards that apply for the certified vehicle. The
demonstration applies for both criteria and GHG emissions. We are
amending 40 CFR 85.525 by removing the requirement to demonstrate
compliance with GHG emissions. Program requirements related to criteria
exhaust, evaporative, and refueling emissions and onboard diagnostics
remain unchanged.
The regulation at 40 CFR 85.1515 describes the standards that apply
for Independent Commercial Importers in their practice of importing
used vehicles. We are only removing the provision that disallowed
generation and use of GHG emission credits. We note further that the
regulation requires Independent Commercial Importers to meet all the
standards that apply under 40 CFR part 86. With the other changes
described in this action, the removal of GHG standards from 40 CFR part
86, subpart S, applies equally to imported vehicles. Imported vehicles
continue to be subject to criteria exhaust, evaporative, and refueling
emission standards and requirements for onboard diagnostics as
specified in 40 CFR part 86, subpart S.
We are revising the recall-related instructions for remedial plans
and consumer notification in 40 CFR 85.1803 and 85.1805 to remove a
reference to 40 CFR 86.1865-12(j)(3), which we are removing in this
action. The referenced paragraph relates to recall provisions for
vehicles that do not comply with GHG standards. We are also revising
definitions of ``Emission-related defect'' and ``Voluntary emissions
recall'' in 40 CFR 85.1902 where those definitions describe how
manufacturers must report GHG-related defects differently than defects
related to criteria pollutant emission standards.
[[Page 7741]]
Finally, we proposed to amend the warranty provisions for specified
major emission control components in 40 CFR 85.2103 by removing the
reference to batteries serving as a Renewable Energy Storage System
(RESS) for electric vehicles and plug-in hybrid electric vehicles,
along with all components needed to charge the system, store energy,
and transmit power to move the vehicle. Some commenters supported this
proposed change. Other commenters noted that RESS provisions are not
limited to greenhouse gas emissions and that the Agency specifically
connected the warranty provisions to its nonmethane organic gases and
oxides of nitrogen (NMOG+NOX) standards in the 2024 LD and
MD Multi-Pollutant Emission Standards Rule.\206\ Considering the
connection to the EPA criteria pollutant program, which is out of scope
of this rulemaking, we are not taking final action at this time on the
proposal to remove batteries serving as a RESS for electric vehicles
and plug-in hybrid electric vehicles from the list of specified major
emission control components in 40 CFR 85.2103(d)(1). We may consider
revisions in a future criteria pollutant rule. Note that we are
nevertheless finalizing the proposed change to remove 40 CFR
85.2103(d)(3), which established the newly required battery monitor as
the basis for making battery-related warranty claims; since we are
removing the requirement to install these dashboard-mounted battery
monitors in this rulemaking, warranty implementation will necessarily
proceed without the benefit of information from the battery monitor.
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\206\ 89 FR 27965 (Apr. 18, 2024).
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b. 40 CFR Part 86--Emission Standards and Certification Requirements
for Light- and Medium-Duty Vehicles
In general, we are amending 40 CFR part 86 to remove all GHG
emission standards, references to such standards, and related
provisions while retaining provisions that support our criteria
pollutant emission program. In this preamble subsection, we describe
several amendments that are necessary to remove GHG-related provisions
from 40 CFR part 86 while ensuring that criteria pollutant emission
standards are not substantively impacted. Table 9 provides a summary of
the amendments to 40 CFR part 86.
[GRAPHIC] [TIFF OMITTED] TR18FE26.011
We are amending the list of materials incorporated by reference in
40 CFR 86.1 by removing material that is referenced only in regulations
that we are removing in this final action.
We are amending the applicability statements in 40 CFR 86.1801-12
by removing references to GHG standards and related compliance
provisions. We are also removing the instruction related to work factor
for vehicles above 14,000 pounds gross vehicle weight rating (GVWR) at
40 CFR 86.1801-12(a)(3) since that is meaningful only in the context of
GHG standards. We adopted the work-factor provision in a 2016 final
rule as a means of limiting the extent to which manufacturers would
certify those larger HD vehicles in test groups along with chassis-
certified MD vehicles.\207\ Removing the instruction to calculate GHG
standards based on a work factor appropriate for MD vehicles, without
other compensating changes, could lead to a greater number of HD
vehicles certified as MD vehicles. The work-factor provision was
adopted as a means of addressing competing concerns from different
manufacturers. As a result, we are limiting this provision to HD
vehicles with a maximum value of 19,500 pounds GVWR. We believe this
limitation is the best way to maintain a consistent approach for
certifying affected vehicles.
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\207\ 81 FR 73478 (Oct. 25, 2016).
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We are amending the definitions in 40 CFR 86.1803-01 by removing
several defined terms that are used only in regulatory provisions that
we are removing in this final action. This includes removing the
definition of ``configuration''; while this definition is no longer
needed, we are retaining the slightly different definition of ``vehicle
configuration,'' since that definition is needed to support standards
related to criteria pollutants. We are accordingly amending several
references across 40 CFR part 86, subpart S, to change from a generic
reference to ``configuration'' and replace it with the specific
reference to ``vehicle configuration.'' We are also amending 40 CFR
86.1803-01 by adding a definition for ``work factor'' that is
consistent with the definition that is embedded in 40 CFR 86.1819-14.
We adopted the definition of ``work factor'' in 40 CFR 86.1819-14
primarily as a means of accounting for specific vehicle characteristics
in establishing GHG emission standards for MD vehicles. We are removing
all of 40 CFR 86.1819-14 as described below. However, we are keeping
the definition of work factor to support the definition
[[Page 7742]]
of ``medium-duty passenger vehicle,'' which relies on the work factor
concept to categorize vehicles for applying criteria pollutant emission
standards.
We are amending 40 CFR 86.1803-01 and 86.1809-12 by removing
references to the air conditioning efficiency test as part of the
consideration for determining what is a defeat device. We are
eliminating the air conditioning efficiency test from the EPA
certification program because it has been used only to generate GHG
credits. Note that we are not removing the air conditioning efficiency
credit provisions and measurement procedures from 40 CFR 86.1868-12 and
1066.845, which are used by manufacturers for compliance with fuel
economy standards as described in 40 CFR 600.510-12(c)(3). If in the
future NHTSA changes the fuel economy standards to no longer reference
air conditioning efficiency credits, we intend to remove those
provisions from 40 CFR 600.513 if they become obsolete.
We are amending useful life specifications in 40 CFR 86.1805-12 and
86.1805-17 by removing references to useful life for GHG standards.
Useful life for all criteria exhaust, evaporative, and refueling
emission standards and onboard diagnostics remain unchanged.
In response to public comments, we are amending 40 CFR 86.1806-27
to clarify we are excluding certain information items identified in 13
CCR 1968.2 because they are related to GHG emission standards.
We are amending labeling requirements in 40 CFR 86.1807-01 by
removing the requirement for battery electric vehicles (BEVs) and plug-
in hybrid electric vehicles (PHEVs) to identify monitor family and
battery durability family on the vehicle emission control information
label. We are removing the battery monitoring and battery durability
requirements in 40 CFR 86.1815-27 and therefore no longer need to
include this family information as part of the certification process.
We are amending 40 CFR 86.1810-09(f)(2) by removing references to
GHG emission standards. Manufacturer requirements to comply with
altitude-related demonstration requirements for vehicles subject to the
cold temperature standards for nonmethane hydrocarbon emissions remain
unchanged.
We are amending 40 CFR 86.1810-17(j) by removing references to GHG
emission standards. Small-volume manufacturers that modify a vehicle
already certified by a different company must continue to meet other
requirements as specified, such as those related to criteria exhaust,
evaporative, and refueling emissions and onboard diagnostics.
We are amending 40 CFR 86.1811-17, 86.1811-27, and 86.1816-18 by
removing references to GHG emission standards. We are not otherwise
changing these sections, which establish criteria exhaust emission
standards for LD and MD vehicles.
We are removing 40 CFR 86.1815-27, as proposed. We adopted this
section to establish battery monitoring and battery durability
requirements for BEVs and PHEVs. Since the earliest battery monitoring
and battery durability requirements were scheduled to start in MY 2027,
removing those requirements involves no immediate transition to
discontinue compliance for certified vehicles.
We are removing 40 CFR 86.1818-12 and 86.1819-14. These sections
described the GHG standards and implementing provisions for MY 2010 and
later LD vehicles and for MY 2014 and later MD vehicles. We are
discontinuing the requirement to demonstrate compliance with these GHG
standards and note that this discontinuation applies as of the
effective date of the final action. Manufacturers need not amend
existing certificates for ongoing production for the current MY.
Manufacturers will in any case not need to submit credit reports at the
end of the current MY to demonstrate compliance with the fleet average
CO2 standards.
We are amending test group specifications in 40 CFR 86.1823-08 by
removing durability demonstration requirements related to GHG emission
standards.
We are amending the provisions for establishing test groups in 40
CFR 86.1827-01 by removing the reference to CO2 emission
standards.
We are amending testing specifications in 40 CFR 86.1829-15 by
removing references to battery durability requirements and GHG emission
standards, except where needed to account for emission measurements
related to fuel economy labeling.
We are amending the compliance provisions 40 CFR 86.1835-01,
86.1838-01, 86.1841-01, 86.1848-10, and 86.1854-12 by removing
references to GHG emission standards.
We are removing the description of battery monitor families and
battery durability families and other GHG-related items from the
reporting requirements in 40 CFR 86.1844-01.
We are amending carryover testing provisions in 40 CFR 86.1839-01
by removing references to accuracy requirements for battery monitoring
for electric vehicles (EVs), which included battery electric vehicles
and fuel cell electric vehicles, and PHEVs.
We are amending instructions for the application for certification
in 40 CFR 86.1844-01 by removing references to refrigerant leakage
rates and GHG emission standards.
We are amending in-use testing requirements in 40 CFR 86.1845-04
and 86.1846-01 by removing references to testing GHG emissions and
testing related to battery monitor accuracy and battery durability for
EVs and PHEVs. We are also amending 40 CFR 86.1845-04 by changing the
nomenclature for the reference brake-specific CO2 emission
rate needed to perform calculations related to in-use testing for
engines certified under 40 CFR 1036.635 for use in vehicles with high
towing capacity.
We are removing requirements for battery durability testing and
other GHG-related provisions in 40 CFR 86.1847-01 and 86.1848-10.
We are amending the credit provisions for criteria exhaust and
evaporative emissions in 40 CFR 86.1861-17 by referencing the credit
provisions in 40 CFR part 1036, subpart H, instead of 40 CFR part 1037,
subpart H. We are removing several credit provisions in 40 CFR part
1037, subpart H, in this rule because they were needed only in relation
to the GHG standards in 40 CFR part 1037, which we are removing in this
rule. The referenced credit provisions in 40 CFR part 1037, subpart H,
are equivalent to the analogous credit provisions in 40 CFR part 1036,
subpart H. While the final action preserves some credit-related
provisions in 40 CFR part 1037 in support of NHTSA's fuel consumption
standards, we are finalizing as proposed the updated references to 40
CFR part 1036 to ensure the complete subpart of the EPA averaging,
banking, and trading provisions can continue to apply under 40 CFR
86.1861-17. We are also amending 40 CFR 86.1861-17 by removing a
reference to 40 CFR 86.1865-12(j)(3), which we are removing in this
action.
We are removing 40 CFR 86.1865-12, which described the emission
credit provisions related to the fleet average GHG standards. See the
discussion related to 40 CFR 86.1818-12 and 86.1819-14 for the
transition to discontinued GHG standards for the MY currently in
production for the year when the final action is effective. More
specifically, we will no longer recognize manufacturers' positive or
negative GHG credit balances as of the effective date of the final
action. Note also that we are removing 40 CFR 86.1865-12(j)(3), which
describes recall provisions for
[[Page 7743]]
vehicles that do not comply with GHG standards. We recognize that a
credit-based approach to recall is no longer appropriate without a GHG
credit program. In the context of NMOG+NOX standards, recall
would involve identifying and correcting a vehicle defect to bring
vehicles into compliance with standards. Accordingly, we are removing
the provisions describing a credit-based remedy for noncompliance.
We are removing 40 CFR 86.1866-12, 86.1867-12, and 86.1867-31.
These sections describe GHG credit programs for advanced technology and
air conditioning leakage that served only in relation to the GHG
standards that we are removing in this action.
We are amending the credit provisions for air conditioning
efficiency and for off-cycle technologies in 40 CFR 86.1868-12 and
86.1869-12 by removing references to the fleet average GHG standards
and adjusting the description to clarify that these credit provisions
continue to serve as inputs for calculating fuel consumption
improvement values and average fuel economy for LD program vehicles
under 40 CFR 600.510-12. Note that the 2024 LD and MD Multi-Pollutant
Emission Standards Rule included several changes to narrow the
availability of air conditioning efficiency and off-cycle credits;
those changes continue to apply in the context of fuel consumption
improvement values and average fuel economy.\208\
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\208\ 89 FR 27842 (Apr. 18, 2024).
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We are removing 40 CFR 86.1870-12, which described a GHG credit
program for full-size pickup trucks with hybrid technology. Those GHG
credits were also used for calculating fuel consumption improvement
values and average fuel economy for LD program vehicles under 40 CFR
600.510-12. However, we amended those credit provisions in the 2021
final rule to establish MY 2024 as the last year that manufacturers
could generate those credits.\209\ Because those credits are already
discontinued for purposes of demonstrating compliance with EPA emission
standards, manufacturers can no longer use those provisions to create
fuel consumption improvement values under 40 CFR part 600.
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\209\ 86 FR 74434 (Dec. 30, 2021).
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c. 40 CFR part 600--Requirements Related to Fuel Economy for Light- and
Medium-Duty Vehicles
In general, we are amending 40 CFR part 600 to remove all
references to GHG emission standards and related provisions while
retaining provisions that support compliance with CAFE standards and
fuel economy labeling for passenger cars and light trucks. In the
remainder of this preamble subsection, we describe several amendments
needed to remove GHG-related provisions from 40 CFR part 600 without
affecting provisions related to CAFE standards and fuel economy
labeling. Table 10 provides a summary of the regulations we are either
removing from or amending in 40 CFR part 600.
[GRAPHIC] [TIFF OMITTED] TR18FE26.012
We are amending the applicability statements in 40 CFR 600.001 by
removing references to carbon-related exhaust emissions and fleet
average CO2 standards. We are also revising the reference in
40 CFR 600.001(a) to MD vehicles because the testing and reporting
provisions remain only to support fuel-consumption standards that apply
under 49 CFR part 535. Testing provisions will remain to describe (1)
how passenger automobiles and light trucks (including MD passenger
vehicles) must meet fuel economy standards, (2) how manufacturers must
prepare fuel economy labels for those vehicles, and (3) how MD vehicles
must meet fuel-consumption standards.
We are amending the definitions in 40 CFR 600.002 by removing the
reference to fleet average CO2 standards. We are also
amending several definitions related to MD vehicles to preserve content
referenced in 40 CFR 86.1819-14, which we are removing in this final
action. We are amending these definitions to support NHTSA's
implementation of fuel-consumption standards for MD vehicles.
We are amending the definition of Medium-Duty Passenger Vehicle
(MDPVFE) for purposes of fuel economy testing and reporting
in 40 CFR 600.002 to align with the clarified definition published by
NHTSA at 49 CFR 523.2 (89 FR 52945, June 24, 2024). Aligning these
definitions is necessary to ensure the EPA's test procedures are
properly applied to vehicles covered by fuel economy standards and
labeling requirements.
As described for 40 CFR 86.1803-01, we are amending several
references across 40 CFR part 600 to change from a generic reference to
``configuration'' and replace it with the specific reference to
``vehicle configuration.''
We are amending the information requirements in 40 CFR 600.006
through 600.010 by removing references to carbon-related exhaust
emissions, GHG
[[Page 7744]]
emission standards, and reporting GHG-related information generally.
We are amending the testing overview in 40 CFR 600.101 and 600.111-
08 by removing references to carbon-related exhaust emissions and fleet
average CO2 emissions.
We are amending the emission calculations in 40 CFR 600.113-12 by
removing references to carbon-related exhaust emissions and other GHG
emissions.
We are amending the interim testing provisions in 40 CFR 600.117 by
removing paragraph (a)(5) since we are discontinuing GHG testing with
in-use vehicles under 40 CFR 86.1845-04. We are also revising
paragraphs (a)(6) and (b) to clarify that manufacturers do not adjust
measured fuel economy values to account for fuel effects, whether they
test with E0 or E10 gasoline.
We are amending the testing, calculation, and reporting
specifications in 40 CFR 600.116-12, 600.507-12, 600.509-12, and
600.510-12 by removing references to carbon-related exhaust emissions.
We are also removing GHG-specific utility factors in 40 CFR 600.116-12.
We note that calculations related to off-cycle credits in 40 CFR
600.510-12(c)(3)(ii) continue to rely on carbon-related exhaust
emissions as specified in 40 CFR 86.1869-12.
We are amending the reporting requirements in 40 CFR 600.512-12 by
removing references to carbon-related exhaust emissions. This includes
amending 40 CFR 600.512-12(c)(5)(i) to explain that the purpose for
performing the calculations in 40 CFR 600.510-12(c)(3) is to support
credit calculations for fuel economy improvement factors, rather than
demonstrating compliance with the fleet average standard for carbon-
related exhaust emissions. We are moving the existing reporting
requirement for emission credits related to fuel consumption
improvement values from 40 CFR 86.1865-12(l)(2)(iii), which we are
removing in this final action, to 40 CFR 600.512-12(c)(3) to preserve
the existing provisions needed for fuel economy reporting. We are also
removing the reporting requirements in 40 CFR 600.514-12, which are
solely related to GHG emissions.
C. Heavy-Duty Engine and Vehicle GHG Program
This section VII.C includes background on the EPA's HD GHG emission
program and describes changes to the engine-based GHG regulations and
the vehicle-based GHG regulations we are finalizing after considering
comments.
1. Background on the Heavy-Duty Engine and Vehicle GHG Program
The EPA promulgated new GHG emission standards for HD engines and
vehicles in three separate rulemakings. In 2011, the EPA established
the first GHG standards for MY 2014 and later HD engines and vehicles
in an action titled ``Greenhouse Gas Emissions and Fuel Efficiency
Standards for Medium- and Heavy-Duty Engines and Vehicles'' (HD GHG
Phase 1).\210\ In 2016, the EPA set new GHG standards for MY 2021 and
later HD engines and vehicles in an action titled ``Greenhouse Gas
Emissions and Fuel Efficiency Standards for Medium- and Heavy-Duty
Engines and Vehicles--Phase 2'' (HD GHG Phase 2).\211\ Most recently,
in 2024, the EPA finalized the 2024 HD GHG Emission Standards Rule,
which set new CO2 emission standards for MY 2032 and later
HD vehicles that phase in starting as early MY 2027 for certain vehicle
categories.\212\ The phase-in revises MY 2027 GHG standards that were
established previously under the EPA's HD GHG Phase 2 rulemaking.\213\
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\210\ 76 FR 57106 (Sept. 15, 2011).
\211\ 81 FR 73478 (Oct. 25, 2016).
\212\ See 89 FR 29559-61 (Apr. 22, 2024).
\213\ 89 FR 29440 (Apr. 22, 2024).
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The EPA and NHTSA jointly issued the HD GHG Phase 1 and HD GHG
Phase 2 rulemakings covering HD GHG emission and fuel efficiency
standards. The EPA set GHG emission standards under CAA section 202(a),
and NHTSA set fuel consumption standards under EISA.\214\ The EPA and
NHTSA programs were harmonized through MY 2026; however, NHTSA did not
adopt changes in fuel consumption standards corresponding to the EPA's
HD GHG Phase 3 standards. As a result, the CO2 emission and
fuel consumption standards diverged in MY 2027 and later.
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\214\ 49 U.S.C. 32902(k).
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The EPA's regulations include the test procedures along with a
certification and compliance program, which is led by the EPA. As noted
previously, this regulatory structure was designed to maximize
efficiency within the Federal government and minimize the burden on the
engine and vehicle manufacturers by centralizing data submission.
Manufacturers submit data and information to the EPA and the EPA, in
turn, shares information with NHTSA as needed to support NHTSA's
implementation of its fuel consumption standards.\215\
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\215\ See 49 CFR 535.8; 40 CFR 1036.755 and 1037.755.
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2. Summary of Comments and Updates to the Heavy-Duty Engine and Vehicle
Programs
Engine and vehicle manufacturers, trade associations for the
manufacturers and suppliers, and other special interest groups
commented specifically on the regulatory updates the EPA proposed for
the HD engine and vehicle GHG programs. Many of these commenters raised
a common concern that informed the approach we are finalizing for our
HD engine and vehicle regulations: the HD industry's request to ensure
no disruption to NHTSA's fuel efficiency program. Section VII.C.2 of
this preamble summarizes comments related to that concern and describes
the approach we are broadly applying to the regulations after
considering those comments. We note that several commenters suggested
more specific changes to regulatory sections we proposed to revise or
remove, and some commenters identified additional regulatory sections
we should consider revising or removing. In section VII.C.3 of this
preamble, we summarize the comments related to specific regulatory text
and changes we are finalizing after considering those comments. See the
Response to Comments document for more detailed summaries of and
responses to comments related to specific HD engine and vehicle GHG
regulations.
Commenters responded to the EPA's request for comment on the
relationship between the EPA's and NHTSA's regulations. As stated at
proposal, NHTSA's medium- and heavy-duty fuel efficiency regulations in
49 CFR part 535 refer to several sections in the EPA's 40 CFR parts
1036 and 1037 that the EPA proposed to modify or remove. In the
proposal, we also noted that NHTSA's reporting and recordkeeping
regulation in 49 CFR 535.8(a)(6) directs manufacturers to submit
information to the EPA, and 49 CFR 535.8(a)(6) also provides direction
to manufacturers to send the information directly to NHTSA in instances
where the EPA does not have an electronic pathway to receive the
information.\216\ We requested comment on whether any of the EPA's GHG
test procedure, certification, and compliance program regulations
should be retained with a CFR notation explaining that they only apply
to NHTSA's HD fuel efficiency program. Regarding reporting, we also
requested comment on the time required to transition from manufacturers
supplying
[[Page 7745]]
data to the EPA to supplying the data directly to NHTSA.
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\216\ See 49 CFR 535.8(a)(6).
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Engine and vehicle trade organizations, individual manufacturers,
and other organizations that commented on this topic expressed concern
about the proposal to remove the EPA's GHG regulations, indicating that
it would disrupt near-term certification for engine and vehicle
manufacturers who would continue to be subject to fuel consumption
standards under the NHTSA's fuel efficiency program. These commenters
suggested that the EPA retain some or all of its GHG regulations until
NHTSA is able to revise 49 CFR part 535 to independently implement
their fuel efficiency program. In general, we agree with commenters
that manufacturers should continue to have access to the regulations
needed for NHTSA to effectively implement their program. At this time,
NHTSA has not finalized regulations to update their HD fuel efficiency
program under 49 CFR part 535. Therefore, after considering comments,
and consistent with our request for comment on whether any of these
provisions should be retained to support NHTSA's HD fuel efficiency
program, we are only removing as proposed the EPA GHG standards in 40
CFR 1036.108, 1037.105, and 1037.106 and other provisions in 40 CFR
parts 1036 and 1037 that only apply for the EPA. Relatedly, as
discussed in more detail in section VII.C.3.c of this preamble, we are
retaining regulatory provisions so that manufacturers will continue to
submit their data and information to the EPA until NHTSA has updated
their regulations and is prepared to accept the manufacturers' data and
information directly.
To ensure NHTSA's fuel efficiency program remains implementable in
the near-term, we are retaining the EPA regulations in 40 CFR parts
1036 and 1037 that NHTSA references. The Response to Comments document
for this final action describes specific changes we are finalizing to
remove the EPA's GHG standards and retain the necessary provisions for
NHTSA's fuel efficiency program. We note here that we have generally
replaced references to ``CO2 standards'' with ``fuel
consumption standards'' throughout 40 CFR parts 1036 and 1037. However,
we have not removed all references to CO2 emissions
throughout these parts. CO2 emissions remain the basis of
many of the test procedures and compliance provisions used in NHTSA's
fuel efficiency program. As such, we are retaining many of the
requirements to measure and report CO2 emissions in 40 CFR
parts 1036 and 1037 to support the NHTSA's fuel efficiency program. To
avoid extensive revisions throughout the parts, we are also amending
the 40 CFR 1036.801 and 1037.801 definitions of ``we (us, our)'' to
mean the EPA for issues related to criteria pollutant standards and to
include NHTSA for testing, compliance, and approvals related to fuel
consumption standards.
Another commenter expressed a preference that the EPA also retain
its current responsibility for certification, noting that the
Environment and Climate Change Canada (ECCC) currently accepts EPA
certification and labeling for their greenhouse gas program, which
simplifies the certification process for manufacturers exporting their
vehicles to Canada. We will not be continuing to provide EPA
certifications for GHG emissions because we are removing the GHG
emission standards in this final action.
While some manufacturers expressed support for the broad rescission
of all of the EPA's GHG regulations, other industry commenters focused
their comments specifically on the HD GHG Phase 3 program, noting that
the Phase 3 standards are infeasible and that the rule was an ``EV
mandate'' in violation of the major questions doctrine. More
consistently, commenters from the HD industry noted their urgent need
for regulatory certainty regarding the HD GHG Phase 3 standards that
are currently set to apply for MY 2027. These commenters indicated that
this final action is likely to be challenged, which could lead to the
possibility that the final action would be stayed and the existing GHG
regulations would remain in place, including the more stringent
standards beginning in MY 2027. One approach suggested by commenters to
provide near-term certainty was that the EPA rescind the Phase 3
program separate from the Endangerment Finding rescission and allow
industry to continue to meet the MY 2024 standards that are currently
in place under the HD GHG Phase 2 program. Another suggested approach
was that the EPA add a severability clause to the final action to allow
for canceling or revising the GHG standards as originally adopted for
MY 2027 and later vehicles and engines even if the Endangerment Finding
or the broader GHG emission standards are not rescinded. The EPA is
removing all GHG emission standards as noted in this preamble because
we lack authority to set these standards. Therefore, we are not putting
in place alternative GHG emission standards and are not committing to
alternative GHG emission standards in a separate action. As stated
previously, companies are still able to continue producing HD vehicles
that meet the now non-existent HD engine and vehicle requirements if
they so choose.
3. Changes to the Heavy-Duty Engine and Vehicle GHG Regulations
The EPA's HD engine and vehicle emission regulations are contained
in two standard-setting parts. 40 CFR part 1036 includes the engine-
based emissions regulations for both criteria pollutant and GHG
emissions.\217\ 40 CFR part 1037 includes the vehicle-based emission
regulations for criteria pollutant exhaust emissions, evaporative and
refueling emissions, and GHG emissions.
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\217\ Note that HD engine manufacturers are subject to criteria
pollutant standards in 40 CFR part 86, subpart A, through MY 2026.
In a recent rulemaking (88 FR 4296, Jan. 24, 2023), the EPA migrated
criteria pollutant regulations from 40 CFR part 86, subpart A, to 40
CFR part 1036 with new requirements that apply to MY 2027 and later
HD engines. See 88 FR 4326.
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In the following preamble subsections, we describe the removal and
amendment of specific portions of each of these regulatory parts. This
action removes the MY 2014 and later HD GHG emission standards
promulgated in HD GHG Phase 1, Phase 2, and Phase 3, collectively. As
noted in section VII.C.2 of this preamble, in general we are retaining
many provisions for NHTSA's fuel efficiency program under 49 CFR part
535. If NHTSA updates their regulations, then the EPA would consider a
separate rulemaking to remove the remaining provisions related to the
NHTSA fuel efficiency program, including the EPA's data collection
responsibilities.
a. 40 CFR Part 1036--Emission Standards and Compliance Provisions for
Heavy-Duty Engines
40 CFR part 1036 contains regulations related to the final action
titled ``Control of Emissions from New and In-Use Heavy-Duty Highway
Engines.'' 40 CFR part 1036 continues to include emission standards and
compliance provisions for criteria pollutant emissions and evaporative
and refueling emissions that remain unchanged, but we are removing
emission standards and compliance provisions for GHG exhaust emissions
(i.e., CO2, nitrous oxide (N2O), and methane
(CH4) for HD engines) in this final action, consistent with
our proposal. 40 CFR part 1036 is divided into nine subparts with three
appendices. Subpart A defines the applicability of part 1036 and gives
an overview of regulatory requirements. Subpart B describes the
emission standards and other requirements that must be met to certify
engines under
[[Page 7746]]
this part. Subpart C describes how to apply for a certificate of
conformity for HD engines. Subpart D addresses testing of production
engines and hybrid powertrains. Subpart E addresses in-use testing,
while Subpart F describes how to test engines to demonstrate compliance
with the emission standards. Subpart G describes requirements,
prohibitions, and other provisions that apply to engine manufacturers,
vehicle manufacturers, owners, operators, rebuilders, and all others.
Subpart H describes how manufacturers can optionally generate, bank,
trade, and use emission credits to certify HD engines. Subpart I
includes definitions and other reference material. Appendix A includes
a summary of previous emission standards. Appendix B includes the
transient duty cycles. Appendix C includes engine fuel maps used in the
certification of specific vehicles to meet the HD vehicle emission
standards.
This preamble subsection includes an overview of the regulations
related to the HD engine program we are removing or revising. In
general, we are amending 40 CFR part 1036 to remove all GHG emission
standards, references to such standards, and certain related
provisions; however, most of 40 CFR part 1036 is retained as it is for
the EPA's HD engine criteria pollutant emission program. As described
in section VII.C.2 of this preamble, after considering comments, we are
also retaining provisions to which NHTSA specifically refers in their
fuel efficiency regulations of 49 CFR part 535. In this preamble
subsection we describe the amendments we are finalizing for 40 CFR part
1036, which include revising or removing GHG-related provisions and
clarifying when a provision is retained specifically for NHTSA's fuel
efficiency program; some amendments are also needed to retain the
efficacy of the EPA's criteria pollutant emission standards. Table 11
provides a summary of the regulations we are removing or amending in 40
CFR part 1036 or have retained specifically for NHTSA's fuel efficiency
program.
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In 40 CFR part 1036, subpart A, we added clarification in a new 40
CFR 1036.1(e) noting that the test procedure and compliance elements
that previously applied to GHG emission standards, now only apply to
implement NHTSA's HD fuel efficiency standards in 49 CFR part 535. We
are finalizing minor changes to 40 CFR 1036.5(a) to differentiate more
clearly the certification requirements for MD vehicles from those for
HD engines.
Within 40 CFR part 1036, subpart B, we are removing as proposed 40
CFR 1036.108, which included the GHG emission standards for
CO2, N2O, and CH4. We are retaining
for NHTSA 40 CFR 1036.115(b) and 1036.130(c), which refer to fuel maps.
As proposed, we are removing, and reserving to otherwise retain the
existing section numbering, several paragraphs from 40 CFR 1036.150
that described interim provisions that have equivalent provisions in 49
CFR part 535 or only applied for the EPA's GHG program, including: 40
CFR 1036.150(b), (e), (g)-(j), (l), (p), (w) and (aa). While we did
propose to remove paragraphs (d), (m), (n), and (q)-(s), these interim
provisions apply for NHTSA's program, and we are
[[Page 7748]]
retaining them with revisions to remove references to GHG emission
standards.
We did not propose changes to the onboard diagnostic (OBD)
regulations in 40 CFR part 1036, subpart B but we received comments
that GHG-related requirements are embedded within California's 2022
OBD-II regulations that the EPA incorporates by reference. Commenters
requested that the EPA exclude active technology, CO2
parameters, and reporting CO2 results during an OBD
demonstration in the same manner as we previously excluded other
specific California OBD requirements that did not apply for meeting the
EPA regulations. Since we are removing GHG standards and related
requirements in this final action, we agree that it is appropriate to
also remove the requirement to monitor GHG parameters as part of OBD.
For the final action, to conform with our removal of the EPA GHG
standards, we are adding new paragraphs 40 CFR 1036.110(b)(14) through
(18) to exclude the definition of ``Active Technology'' and related
standardization, data storage, certification documentation, and
monitoring system demonstration requirements from the EPA OBD
provisions under 40 CFR 1036.101.
In 40 CFR part 1036, subpart C, we are retaining for NHTSA
references to family emission limit (FEL) and family certification
limit (FCL) that we proposed to remove, and are generally replacing
references to CO2 FCLs or standards with more generalized
text to apply for NHTSA. Also, for NHTSA, we are retaining with
revisions 40 CFR 1036.230(f) and (g) that we proposed to remove. The
revised 40 CFR 1036.230(f) and (g) now refer to 49 CFR part 535 and
remove references to GHG standards in the description of how
manufacturers divide their product lines into engine families. In 40
CFR 1036.230(f)(5) and throughout 40 CFR part 1036, we remove reference
to EPA approvals related to GHG emissions. Therefore, under this final
action, manufacturers would only need to obtain approval from NHTSA for
elements related to their fuel efficiency program. We are also
finalizing several revisions in 40 CFR 1036.235 to refer to 49 CFR part
535 and remove references to GHG emission testing requirements. In 40
CFR 1036.235(a), we are migrating text from 40 CFR 1037.235(a) that
provides direction on how manufacturers select the test powertrain to
replace GHG-related testing requirements in 40 CFR 1036.235(a)(4). We
are retaining for NHTSA 40 CFR 1036.241 that we proposed to remove but
are finalizing revisions to refer to 49 CFR part 535 and removing
references to GHG standards in the description of how to demonstrate
compliance.
Also in 40 CFR part 1036, subpart C, we are migrating as proposed
the provisions that relate to powertrain families from the vehicle
standard-setting part in 40 CFR 1037.231 to the engine standard-setting
part as a new 40 CFR 1036.231 and are finalizing revisions described in
this section VII.C.3.a of the preamble. In a previous rule (89 FR
29616, Apr. 22, 2024), we migrated the powertrain test procedure from
the HD vehicle procedures (formerly 40 CFR 1037.550) to the HD engine
procedures in 40 CFR 1036.545 because we expected powertrain testing to
be primarily used by engine manufacturers. Similarly, we proposed to
migrate the related provisions manufacturers would use to divide their
product line into powertrain families by migrating the text from the
vehicle program in 40 CFR 1037.231 to a newly created section in the
engine program under 40 CFR 1036.231. We are finalizing that migration
and modifying as proposed the text previously under 40 CFR
1037.231(b)(1), such that the new 40 CFR 1036.231(b)(1) no longer
requires powertrains to share the same engine families described in 40
CFR 1036.230 but requires the engine share the same design aspects
specified in 40 CFR 1036.230. Since a manufacturer may choose to
certify the whole powertrain to the standards in 40 CFR part 1036,
there would only be a powertrain family, not a certified engine family
that contains just the engine. Similarly, and consistent with our
approach for defining engine families in existing 40 CFR 1036.230, we
see no need to limit the powertrain family based on the vehicle service
class the powertrain goes into and therefore did not migrate the
existing 40 CFR 1037.231(b)(2) that requires powertrain families to
share vehicle service class groupings. We are also not migrating
``energy capacity'' as an example attribute in the new 40 CFR
1036.231(b)(10), since it is not needed for the criteria pollutant
standards. Similarly, we are not migrating existing 40 CFR
1037.231(b)(11) since rated output of hybrid mechanical power
technology is also not needed for a criteria pollutant family
definition.
In 40 CFR part 1036, subpart D, we are retaining for NHTSA 40 CFR
1036.301 with revisions to refer to 49 CFR part 535 and remove
references to CO2 in the description of the requirements for
selective enforcement audits.
As previously noted, we retained and did not reopen the in-use
testing procedures in 40 CFR part 1036, subpart E, which apply for the
criteria pollutant emission standards. More specifically, within the
in-use test procedures, we are retaining references to measuring
CO2 for use in required chemical balance test procedures and
to calculate the criteria pollutant emissions values for in-use
testing. Also, in 40 CFR 1036.415(g), we are retaining the existing
text requiring manufacturers to override any adjustable idle-reduction
features on vehicles used for in-use testing; we are not taking action
at this time on the proposed more general statement describing what it
means to be adjustable.
In 40 CFR part 1036, subpart F, we are retaining for NHTSA test
procedures related to developing engine data to support NHTSA's HD
vehicle fuel efficiency program. We are retaining 40 CFR 1036.505,
1036.535, 1036.540, 1036.543, and 1036.550 and the fuel map duty cycle
in Appendix C to part 1036 that we proposed to remove. In 40 CFR
1036.510, we are finalizing several revisions to paragraph (b),
including replacing a reference to 40 CFR 1036.540(c)(2) with a
reference to a new table we are including in that section as proposed
that provides the same gear ratios based on engine service class from
40 CFR 1036.540. We are retaining 40 CFR 1036.510(e) and 1036.512(e),
which described how to determine CO2 emissions for plug-in
hybrid powertrains using the HD engine Federal Test Procedure (FTP) and
engine Supplemental Emissions Test (SET) and duty cycles, respectively,
to support NHTSA's HD fuel efficiency program. In 40 CFR 1036.530(e),
we are retaining the existing requirement that manufacturers measure
CO2 emissions for in-use testing, including the variable
eCO2FTPFCL. We are not taking action at this time on the
revised variable eCO2FTP that we proposed would represent
the engine's brake-specific CO2 over the FTP or SET duty
cycle.
Powertrain testing, also described in 40 CFR part 1036, subpart F,
is an option that manufacturers may use for certifying hybrid
powertrains to the engine criteria pollutant standards in 40 CFR
1036.104 and the GHG emission standards in 40 CFR 1036.108. The
powertrain test procedure in 40 CFR 1036.545 describes testing a
powertrain that includes an engine coupled with a transmission, drive
axle, and hybrid components, or a subset of these components. We
retained and did not reopen most of 40 CFR 1036.545 related to the
powertrain testing for criteria pollutants. We proposed to remove the
portions related to the GHG program and revise several paragraphs to
account for the removed GHG content; however,
[[Page 7749]]
we are retaining these provisions for NHTSA's fuel efficiency program
with targeted revisions to replace references to the EPA's standards
with NHTSA's standards. While we are retaining vehicle test procedures
from 40 CFR part 1037, we are finalizing as proposed the revisions in
40 CFR 1036.545(d) to replace references to the 40 CFR 1037.565 vehicle
test procedure with the relevant text from that procedure.
Throughout 40 CFR 1036.545, we are retaining existing requirements
to create inputs for the Greenhouse gas Emission Model (GEM) tool that
manufacturers use for compliance with NHTSA's fuel efficiency program.
Vehicle manufacturers will continue to have access to GEM Phase 2,
Version 4.0, including the hardware-in-the-loop (HIL) model within that
version of GEM, that is incorporated by reference in 40 CFR 1037.810
and currently available on the EPA's website.\218\ We also are
retaining references to the use of utility factors, vehicle
configurations, and vehicle-based duty cycles and test procedures that
do not apply for the criteria pollutant program but apply to NHTSA's
fuel efficiency program. We are removing as proposed 40 CFR 1036.545(p)
which described the procedure to determine usable battery energy for
plug-in hybrid powertrains that was added in the EPA's HD Phase 3 rule.
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\218\ GEM Phase 2, Version 4.0 is incorporated by reference in
40 CFR 1036.545. See also 40 CFR 1036.810.
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In 40 CFR part 1036, subpart G, we are revising 40 CFR 1036.605 to
remove the EPA N2O requirements for engines installed in
specialty vehicles and the ability to generate or use credits and are
finalizing similar changes in 40 CFR 86.007-11(g) and 86.008-10(g) for
MY 2026 and earlier specialty vehicle engines. We are retaining 40 CFR
1036.610 with a revised section heading to remove reference to GHG
emissions, because NHTSA's regulations in 49 CFR part 535 refer to
these off-cycle technology test procedures. We are also retaining for
NHTSA 40 CFR 1036.615 and 1036.620, with revisions to 40 CFR 1036.620
to remove references to CO2 standards and banked credits,
and the labeling requirement of paragraph (d). We are removing as
proposed 40 CFR 1036.625, which described how to adjust CO2
FEL values; the NHTSA regulations contain their own provisions for
manufacturers to make adjustments to their compliance values and they
do not refer to 40 CFR 1036.625.
We also are removing as proposed 40 CFR 1036.635, which described
how manufacturers that certify engines for use in high-gross combined
vehicle weight (GCWR) MD vehicles under 40 CFR part 1036 could comply
with GHG standards under 40 CFR part 86, subpart S. With no need to
describe the GHG-related flexibilities in 40 CFR 1036.635, the existing
applicability provisions in 40 CFR 1036.1 and 1036.5 already cover the
certification provisions for high-GCWR vehicles as they relate to
criteria pollutants. Specifically, 40 CFR 1036.1 sets up the default of
applying the standards and certification requirements from 40 CFR part
1036 to all engines installed in HD vehicles (generally vehicles above
8,500 pounds GVWR), while 40 CFR 1036.5 allows manufacturers to certify
MD vehicles to the chassis-based program as described in 40 CFR
86.1801-12.
The NHTSA regulations under 49 CFR part 535 contain their own ABT
provisions for calculating and using fuel consumption credits. In 40
CFR part 1036, subpart H, we are generally removing references to the
EPA's CO2 standards and are amending the calculation
provisions to clarify they only apply for the EPA criteria pollutant
credit calculations. We are retaining the ABT reporting provisions of
40 CFR 1036.730, since the EPA will continue to collect the information
as described in 40 CFR 1036.755 for NHTSA's fuel efficiency program.
The allowance for manufacturers to generate credit deficits under 40
CFR 1036.745 is required for NHTSA's ABT program for its fuel
consumption standards. We are retaining for NHTSA 40 CFR 1036.745 and
references to that section within subpart H, but are replacing the
content of 40 CFR 1036.745 with a reference to NHTSA's fuel consumption
credits provisions under 49 CFR 535.7.
In 40 CFR part 1036, subpart I, we proposed to remove GHG-specific
symbols, abbreviations, and acronyms from 40 CFR 1036.805, and
materials from 40 CFR 1036.810 that were only incorporated by reference
in the test procedures we proposed to remove. Similarly, in 40 CFR
1036.801, we proposed to remove several GHG-specific definitions, and
move transmission- and other powertrain-related definitions from the HD
vehicle definitions in 40 CFR 1037.801 to the engine definitions in 40
CFR 1036.801, so they can be available to engine manufacturers using
the powertrain test procedures in 40 CFR 1036.545. For the final
action, we are retaining the provisions in 40 CFR 1036.801, 1036.805,
1036.810, and 1036.815 to provide for the implementation of NHTSA's
fuel efficiency program. We are finalizing as proposed the new
transmission- and other powertrain-related definitions in 40 CFR
1036.801 since the powertrain test procedures are now in 40 CFR part
1036, but note that we are also retaining the same definitions in 40
CFR 1037.801.
We proposed to remove Appendix C to part 1036, which contains the
default engine fuel maps that are used by 40 CFR 1036.540. In this
final action, we are retaining Appendix C, consistent with our decision
to retain 40 CFR 1036.540 and the other provisions needed by NHTSA for
their fuel efficiency program.
b. 40 CFR Part 1037--Emission Standards and Compliance Provisions for
Heavy-Duty Vehicles
40 CFR part 1037 contains regulations related to the final action
titled ``Control of Emissions from New Heavy-Duty Motor Vehicles.'' 40
CFR part 1037 continues to include criteria pollutant emission
standards that apply for all HD vehicles, and evaporative and refueling
emission standards that apply for certain HD vehicles, but we are
removing GHG emission standards, consistent with the proposal. 40 CFR
part 1037 is divided into nine subparts with five appendices. Subpart A
defines the applicability of part 1037 and gives an overview of
regulatory requirements. Subpart B describes the emission standards and
other requirements that must be met to certify vehicles under this
part. Subpart C describes how to apply for a certificate of conformity.
Subpart D and E address testing of production and in-use vehicles,
respectively. Subpart F describes how to test vehicles and perform
emission modeling for vehicles subject to the CO2 emission
standards. Subpart G, along with 40 CFR part 1068, describe
requirements, prohibitions, and other provisions that apply to
manufacturers, owners, operators, rebuilders, and all others. Subpart H
describes how manufacturers can optionally generate and use emission
credits to certify vehicles. Subpart I includes definitions and other
reference material. Finally, Appendix A, B, and D include test cycles,
Appendix C presents emission control identifiers for emissions labels,
and Appendix E presents power take-off utility factors.
This preamble subsection includes an overview of the regulations
related to the HD vehicle program we are removing or revising. In
general, we are amending 40 CFR part 1037 to remove all GHG emission
standards (i.e., CO2 and HFC standards for vehicles),
references to such standards, and certain related provisions without
revising provisions necessary to support criteria pollutant standards,
including
[[Page 7750]]
evaporative and refueling emission standards. As described in section
VII.C.2 of this preamble, after considering comments, we are retaining
provisions to which NHTSA specifically refers in their fuel efficiency
regulations of 49 CFR part 535. In this preamble subsection, we
describe the amendments to revise the GHG-related provisions from 40
CFR part 1037, which include some amendments needed to retain the
efficacy of the criteria pollutant emission standards or clarify when a
provision is retained specifically for NHTSA's fuel efficiency program.
Table 12 provides a summary of the regulations we are removing or
amending in 40 CFR part 1037 or have retained specifically for NHTSA's
fuel efficiency program.
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In 40 CFR part 1037, subpart A, we retained and did not reopen the
existing applicability of 40 CFR part 1037. Specifically, as described
in existing 40 CFR 1037.1, the part continues to apply for BEVs, fuel
cell electric vehicles (FCEVs), and vehicles fueled by conventional and
alternative fuels. We added clarification in a new 40 CFR 1037.1(c)
noting that the test procedure and compliance elements that previously
applied to GHG emission standards, now only apply to implement NHTSA's
HD fuel efficiency program in 49 CFR part 535. We note that the revised
40 CFR part 1037 continues to contain provisions that apply to HD
vehicles under NHTSA's fuel efficiency program; however, it applies for
fewer vehicles under the EPA's criteria pollutant program. Without EPA
GHG standards, there are no vehicle-level emission standards for
vehicles (including glider vehicles) with engines certified to other
parts. Under this final action, the only HD vehicles that would
continue to require a vehicle-level certificate of conformity from the
EPA are those with no installed propulsion engine, such as BEVs and
FCEVs, certifying to the criteria pollutant standards of 40 CFR
1037.102. Tailpipe emissions of criteria pollutants from BEVs and FCEVs
would continue to be deemed to be zero with no testing
[[Page 7751]]
requirements, but the EPA will require that BEV and FCEV manufacturers
apply for a certificate of conformity to meet the requirements of CAA
section 202(a).
In 40 CFR part 1037, subpart B, we are removing the MY 2014 and
later HD vehicle CO2 emission standards promulgated in HD
GHG Phase 1, Phase 2, and Phase 3, which included the vocational
vehicle standards in 40 CFR 1037.105 and the tractor standards in 40
CFR 1037.106. While we are removing GHG standards and related
requirements, we retained and did not reopen criteria pollutant exhaust
emission standards in 40 CFR 1037.102 and the evaporative and refueling
emission standards in 40 CFR 1037.103.
We proposed to revise 40 CFR 1037.102(a) to describe how vehicles
can be deemed to meet the criteria pollutant exhaust emission standards
without testing under 40 CFR part 1037. Commenters raised concerns with
the proposed approach to adopt new vehicle family definitions citing an
associated need for new labeling, tracking systems, and reporting
systems that would require additional time to implement. The commenters
requested to keep today's vehicle family definitions, as they are
required by NHTSA. After considering these comments, we note that the
EPA did not intend for the new vehicle family definitions to increase
burden on certifying manufacturers. Since vehicles with a propulsion
engine are already covered under EPA engine certificates for criteria
pollutants, we do not need to require a separate vehicle certificate
for criteria pollutants. Therefore, we are retaining the current
language in 40 CFR 1037.102(a) and (b) such that only vehicles without
a propulsion engine will continue to be subject to the criteria
pollutant standards in 40 CFR part 1037.
In the HD GHG Phase 2 rulemaking, we adopted PM emission standards
that apply for APUs installed on new tractors. Since PM emissions are
criteria pollutant emissions, we retained and did not reopen the PM
emission standards for APUs but proposed to migrate the standards from
40 CFR 1037.106(g) to a new 40 CFR 1037.102(c) because we proposed to
remove 40 CFR 1037.106. We are finalizing our proposed migration from
40 CFR 1037.106 and are modifying as proposed 40 CFR 1039.699(a) and
(n) to refer to the new 40 CFR 1037.102 instead of 40 CFR 1037.106.
Also in 40 CFR part 1037, subpart B, we are amending 40 CFR
1037.115 to remove the HFC emission (i.e., air conditioning leakage)
standards and the battery durability monitor requirements. We are
revising as proposed the list of components covered under 40 CFR
1037.120(c). Under this final action, we are removing many HD vehicle
GHG-reducing technologies but emission-related warranty would continue
to apply for fuel cell stacks, RESS, and other components used with
BEVs or FCEVs certified to the EPA's criteria pollutant standards or
evaporative and refueling emission controls on vehicles subject to the
EPA's evaporative and refueling standards. We are finalizing as
proposed the removal of warranty requirements from 40 CFR part 1037 for
RESS and other components used in hybrid vehicles. We note that
manufacturers certifying hybrids to the EPA's criteria pollutant
program would be doing so under the engine standards of part 1036 and
would warrant the RESS and other components from those systems under 40
CFR part 1036. We did not reopen or propose to remove the warranty
requirements for hybrid system components in 40 CFR part 1036.
We acknowledge commenters' suggestion that warranty should not
apply for vehicles with no propulsion engine and no tailpipe emissions;
however, these components are covered under the EPA's criteria
pollutant program and the related warranty comments are out of scope
for this action. We did not reopen the requirement that the basic
emission-related warranty applies for fuel cell stacks and RESS as they
continue to qualify as an emission-related component related to
criteria pollutant emission standards. Therefore, we are retaining
these provisions for the final action. Similarly, we retained and did
not reopen the emission control components covering a vehicle's
evaporative and refueling emissions.
Under this final action, we are finalizing a revision to replace
the content of existing maintenance provisions of 40 CFR 1037.125 with
a single sentence requiring manufacturers to provide written
instructions for properly maintaining the emission control system.\219\
In the labeling provisions of 40 CFR 1037.135(c) we are removing as
proposed paragraphs (c)(6) and (7) that relate to identifying the EPA-
specific emission control system and fuel sulfur levels on the label,
respectively. We proposed to remove 40 CFR 1037.140 and 1037.150, which
included the vehicle classifications and interim provisions related
directly to NHTSA's HD vehicle fuel efficiency program. In this final
action, we are retaining 40 CFR 1037.140 with revisions to remove
reference to the EPA's standards and we are retaining the NHTSA-
referenced paragraphs of 40 CFR 1037.150 to assist in the continued
implementation of NHTSA's program.
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\219\ We are not aware of any scheduled maintenance for
evaporative and refueling emission control components, or BEV or
FCEV components, but if there was then the maintenance provisions of
40 CFR 1037.125 would apply.
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In 40 CFR part 1037, subpart C, we proposed to remove 40 CFR
1037.201(g) that describes confirmatory testing; however, in this final
action, we are retaining paragraph (g) for NHTSA's fuel efficiency
program. We proposed to remove several provisions in 40 CFR 1037.205,
which defines what manufacturers would include in their application for
certification, because they would no longer be needed for GHG
certification. However, in this final action we are instead revising 40
CFR 1037.205 to reflect the information that is required for NHTSA's
fuel efficiency program.
We are retaining for NHTSA the existing 40 CFR 1037.225 and
1037.230 with minor revisions to remove reference to GHG and
CO2 standards. After considering comments, we are not
finalizing the streamlined vehicle families we proposed for 40 CFR
1037.230 to avoid additional burden for manufacturers certifying to
NHTSA's fuel consumption standards using the original vehicle families.
We are finalizing as proposed the migration of the powertrain families
provision from 40 CFR 1037.231 to the HD engine regulations under a new
40 CFR 1036.231. We are retaining 40 CFR 1037.231 but replacing the
content of that section with a reference to the new location of the
provision in 40 CFR 1036.231. We proposed to remove 40 CFR 1037.232 and
1037.241 and revise 40 CFR 1037.235 and 1037.250, but are retaining
them for NHTSA in this final action, with targeted revisions to remove
references to GHG and CO2 standards.
We proposed to remove 40 CFR part 1037, subparts D and E in their
entirety because they describe the testing of production and in-use
vehicles to demonstrate compliance with the EPA's HD CO2
emission standards. However, we are retaining these provisions in this
final action for NHTSA's fuel efficiency program. While the EPA would
not be administering any production or in-use testing for GHG
emissions, NHTSA references 40 CFR 1037.301 through 1037.320 which
include audit procedures for inputs to the GEM, tractor aerodynamic
testing, powertrain testing, and axle and transmission testing, and
also references 40 CFR 1037.401 for in-use testing provisions.
[[Page 7752]]
We proposed to remove 40 CFR part 1037, subpart F, in its entirety
because it included the testing and modeling provisions necessary to
certify HD vehicles to the CO2 emission standards. The
provisions in 40 CFR 1037.501 through 1037.570 include procedures for
vehicle-based duty cycles for measuring CO2 emissions,
aerodynamic testing, powertrain component testing, testing with hybrid
power take-off units, and the use of GEM. We are retaining all of 40
CFR part 1037, subpart F because these test procedures are referred to
by NHTSA in 49 CFR part 535. We are retaining the existing text for
most sections of 40 CFR part 1037, subpart F, but we are finalizing
some targeted revisions to 40 CFR 1037.501, 1037.520, 1037.540,
1037.551, and 1037.555 to replace references to CO2
standards with references to NHTSA's fuel consumptions standards. In 40
CFR 1037.560, 1037.565, and 1037.570, we are removing references to
``critical emission-related maintenance'' which only applies for the
EPA. Since the NHTSA regulations currently refer to 40 CFR 1037.550,
which the EPA removed in a previous rule when the powertrain test
procedure was migrated to 40 CFR 1036.545 (89 FR 29616 April 22, 2024),
we are restoring 40 CFR 1037.550 for NHTSA with a single sentence that
directs readers to the correct 40 CFR 1036.545 for the powertrain test
procedure.
We proposed to remove several sections of 40 CFR part 1037, subpart
G, relating to special compliance provisions for the HD vehicle GHG
emission standards. However, we are retaining all of the provisions
required for the implementation of NHTSA's fuel efficiency program in
49 CFR part 535. These sections include provisions related to off-cycle
technologies, advanced technologies, special purpose tractors, variable
vehicle speed limiters, and idle reduction technologies. We are
removing as proposed 1037.645, 1037.665, and 1037.670, which are not
referenced by NHTSA.
We received a comment on 40 CFR 1037.605, in 40 CFR part 1037,
subpart G, which allows manufacturers to use nonroad-certified engines
in certain specialty highway vehicles. While we proposed to remove the
vehicle labeling requirements in 40 CFR 1037.605(d), we did not propose
any changes to paragraphs (a) through (c), which specify how the
provisions apply for vehicle manufacturers using this allowance. The
existing provisions apply for up to 200 all-terrain vehicles with
specific axles, amphibious vehicles, and low speed vehicles. Through MY
2027, the provisions also apply for up to 1,000 vehicles with a hybrid
powertrain where the engine provides energy only for the RESS. The
commenter suggested that the EPA extend the hybrid provision beyond MY
2027 to allow the manufacturer to make a small number of hybrid fire
trucks per year. The commenter cited compliance challenges associated
with obtaining a highway-certified hybrid and that the existing hybrid
sunset date was based on an expected increasing prevalence of HD hybrid
powertrains, which is not occurring. As noted, we did not propose
changes to the general provisions of 40 CFR 1037.605, and, therefore,
this request is outside of the scope of this action. We may consider
changes to this provision in a future rulemaking.
We proposed to remove 40 CFR part 1037, subpart H in its entirety.
The provisions of 40 CFR 1037.701 through 1037.750 describe the
averaging, banking, and trading of CO2 emission credits,
along with associated recordkeeping and reporting requirements. We are
retaining the regulatory provisions that are required by NHTSA for
implementation of the fuel efficiency program. These include 40 CFR
1037.725, 1037.730, 1037.735, 1037.740, 1037.745, and 1037.755. We are
removing as proposed 40 CFR 1037.705, 1037.710, 1037.715, 1037.720, and
1037.750. Throughout subpart H, we replace references to CO2
standards with references to NHTSA's fuel consumption standards,
replace the term ``emission credits'' with a more generic ``credits''
term. Since the NHTSA regulations refer to 40 CFR 1037.745, we are
retaining that section but are replacing the content with a sentence
that points the reader to the equivalent credit deficit provision for
NHTSA's fuel consumption credits under 49 CFR 535.7.
We proposed several revisions in 40 CFR part 1037, subpart I, to
remove the GHG-specific definitions from 40 CFR 1037.801, and symbols,
abbreviations, and acronyms from 40 CFR 1037.805. We also proposed to
remove 40 CFR 1037.810, which includes materials incorporated by
reference to support testing to demonstrate compliance with the HD
vehicle GHG standards. This includes, but is not limited to, the GEM
model and test procedures for measuring the rolling resistance of
tires, tire revolutions per mile, and aerodynamics using coastdown,
wind tunnel, and computational fluid dynamics. We are, however,
retaining nearly all of subpart I in 40 CFR part 1037 because they are
required to support NHTSA's 49 CFR part 535 regulations. We are
removing the definition of ``Phase 3'' and revising the definitions of
``Phase 1'' and ``Phase 2'' to replace references to EPA standards with
NHTSA's fuel consumption standards. As noted in section VII.C.2 of this
preamble, we are also revising the definition of ``we (us, our)'' to
include NHTSA for any regulations we are retaining related to fuel
consumption standards. In Table 1 to paragraph (a) of 40 CFR 1037.805,
we are removing the chemical species methane and nitrous oxide, which
are GHG emissions used only by EPA regulations. In 40 CFR 1037.810, we
are updating as needed references to regulatory sections or paragraphs
that have been removed or changed in this final action.
Lastly, we proposed to remove all appendices to 40 CFR part 1037.
Appendices A, B, and D include the test cycles related to HD vehicle
GHG standards. Appendix C includes the emission control identifiers for
GHG emission labels. Appendix E includes the power take-off unit
utility factors applied in GHG-specific test procedures. We are
retaining all of the existing appendices in 40 CFR part 1037 because
they are required to support NHTSA's 49 CFR part 535 regulations.
c. Relationship Between the EPA's GHG and NHTSA's Fuel Efficiency
Medium- and Heavy-Duty Programs
The current certification and compliance process as relevant for
NHTSA is as follows, separately for HD engines and HD vehicles:
1. Manufacturers submit fuel consumption data to the EPA using the
EPA's electronic certification system following EPA test procedures
included in 40 CFR parts 1036 and 1037;
2. The EPA issues certificates of conformity to the manufacturers;
3. Before and during the MY, the EPA sends the fuel consumption
data and associated information to NHTSA;
4. After the MY, the EPA analyzes end-of-year reports submitted to
the EPA by manufacturers for compliance and shares the fuel consumption
data with NHTSA; and
5. NHTSA manages its compliance process related to the fuel
consumption standards.
We proposed to remove 40 CFR 1036.755 and 1037.755, which describe
the information the EPA provides to the Department of Transportation
related to HD engine and vehicle fuel consumption. We noted that
NHTSA's reporting and recordkeeping regulation in 49 CFR 535.8(a)(6)
directs manufacturers to submit information to the EPA. 49 CFR
535.8(a)(6) also provides direction to manufacturers in instances where
the EPA does not have an electronic pathway to receive the
[[Page 7753]]
information, to send it through an electronic portal identified by
NHTSA, through the NHTSA CAFE database, or to send hardcopy documents
to the address provided in the regulations. We requested comment on the
time required to transition from manufacturers supplying data to the
EPA to supplying the data directly to NHTSA.
Manufacturers and other commenters suggested that the EPA retain
some or all of its GHG regulations until NHTSA is able to revise 49 CFR
part 535 to independently implement their fuel efficiency program.
After considering comments, we are removing as proposed the EPA GHG
standards in 40 CFR 1036.108, 1037.105, and 1037.106 and other
provisions in 40 CFR parts 1036 and 1037 that only apply for the EPA.
However, to ensure NHTSA's fuel efficiency program remains
implementable in the near-term, we are retaining the EPA regulations in
40 CFR parts 1036 and 1037 that NHTSA references, including the
provisions where manufacturers submit data to the EPA.
Therefore, much of the current certification and compliance process
outlined above will remain the same. At this time, the EPA intends to
continue to maintain its Engines and Vehicles Compliance Information
System (EV-CIS) and manufacturers will continue to have an EPA
Designated Compliance Officer for submitting information regarding
NHTSA's fuel efficiency program. However, we note that the EPA would
not grant approvals related to special compliance provisions, issue EPA
certificates of conformity for GHG emissions, or analyze end of year
reports for compliance with the GHG emission standards. Furthermore,
the EPA will perform confirmatory testing, in-use testing, or selective
enforcement audits only in relation to the EPA criteria pollutant
program. We note that vehicle manufacturers will continue to have
access to the GEM Phase 2, Version 4.0 that is incorporated by
reference in 40 CFR 1037.810 and currently available on the EPA's
website. If NHTSA updates their regulations and is prepared to accept
the manufacturers' data and information directly, then the EPA would
consider a separate rulemaking to remove the remaining provisions
related to the NHTSA fuel efficiency program, including the EPA's data
collection responsibilities.
VIII. Statutory and Executive Order Reviews
Additional information about these statutes and Executive Orders
can be found at http://www.epa.gov/laws-regulations/laws-and-executive-orders.
A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 14094: Modernizing Regulatory Review
This is an economically significant regulatory action that was
submitted to OMB for review. Any changes made have been documented in
the docket. The EPA has prepared an RIA for this action to project
impacts as required by E.O. 12866, and it can be found in the
docket.\220\
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\220\ ``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.
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As we stated in the proposal, the EPA has not relied upon any
aspect of the draft RIA or this final RIA as justification for this
rulemaking. Some commenters suggested that the benefit-cost assessments
provided in the draft RIA do not justify repealing the prior standards.
However, the EPA is repealing the GHG emission standards for LD
vehicles, MD vehicles, HD vehicles, and HD engines consistent with the
discussion of legal authority in this preamble, and the EPA is not
relying upon the CAA section 202(a) factors for standard-setting in
this final action. For this final action, we have conducted benefit-
cost assessments pursuant to E.O. 12866, but we recognize that there
are costs and benefits that we are currently unable to fully quantify
and monetize.
Commenters also stated that the EPA should have included an
assessment of air quality and climate impacts from removing the motor
vehicle and engine GHG standards. For this final action, the EPA
performed modeling to estimate changes in criteria pollutants, air
toxics, and GHG emissions. The projected emissions changes can be found
in a memorandum in the docket for this action.\221\ The EPA also
performed climate impacts modeling for this final action, which is
documented in a memorandum in the docket for this action.\222\
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\221\ See Memorandum to Docket EPA-HQ-OAR-2025-0194. ``Projected
Criteria, Air Toxics, and GHG Emissions Impacts for the ``Rescission
of the Greenhouse Gas Endangerment Finding and Motor Vehicle
Greenhouse Gas Emission Standards Under the Clean Air Act'' Final
Rule.''
\222\ See Memorandum to Docket EPA-HQ-OAR-2025-0194.
``Temperature, CO2 Concentration, and Sea Level Rise
Impacts of Greenhouse Gas Emissions from U.S. Motor Vehicles.''
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The analyses provided in the RIA have been revised since the rule
was proposed to reflect a number of considerations, including some
elements highlighted by commenters. The analyses rely on updated
versions of the models used to analyze the impacts of the proposal,
which were based on the models and tools used to estimate impacts of
the light- and medium-duty, and the heavy-duty rules finalized by the
EPA in 2024.\223\ A number of the updates made to the analysis,
including in response to comments, are discussed below. For more
information on updates to the analyses, see the RIA. For more
information on the comments we received on the analysis in the
proposal, as well as our responses, see the Response to Comments
document. In addition to the changes noted in the following paragraphs,
we updated the costs and benefits from 2022 dollars to 2024 dollars.
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\223\ See ``Multi-Pollutant Emissions Standards for Model Years
2027 and Later Light-Duty and Medium-Duty Vehicles: Regulatory
Impact Analysis'', EPA-420-R-24-004, March 2024; and ``Greenhouse
Gas Emissions Standards for Heavy-Duty Vehicles: Phase 3: Regulatory
Impact Analysis, EPA-420-R-24-06, March 2024.
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We received comments that the approach used in the EPA's OMEGA
modeling of GHG standards for the proposed rule did not appropriately
capture removing all GHG standards for LD and MD vehicles. Commenters
stated that instead of extending the MY 2026 GHG standards into MYs
2027 and beyond, a more appropriate modeling approach would be to model
no GHG standards at all, and to allow the OMEGA model to apply less
emissions control technology to vehicles in each MY than in the prior
MY (backsliding). For the analysis of this final action, we revised the
OMEGA modeling assumptions to simulate the removal of all GHG standards
for LD and MD vehicles, and revised the OMEGA model's run settings to
allow backsliding.
Some commenters raised concerns that the 2024 GHG Emission
Standards Rules relied on IRA tax credits and noted that Congress
subsequently eliminated or modified these tax credits in the OBBB. We
agree that our modeling should reflect the actions signed into law in
the OBBB. For the proposal, our modeling assumed all pertinent tax
credits were removed. For this final analysis, we revised our analyses
to align with the OBBB by removing the credits for purchasing (26
U.S.C. 30D) and leasing (26 U.S.C. 45W) LD and MD BEVs; removing the
vehicle purchase tax credits (26 U.S.C. 45W) for HD BEVs and HD FCEVs;
removing the tax credit for electric vehicle supply equipment (EVSE)
installation (26 U.S.C. 30C) for HD BEVs; and adjusting the phase-out
of the advanced manufacturing production credit (26 U.S.C. 45X).
[[Page 7754]]
We received comments suggesting that the Agency's baseline
assumptions for future HD EV market penetration were inflated due to
California's Advanced Clean Truck (ACT) regulation. Congress
disapproved the EPA's waiver for the ACT rule under the CRA. We agree
with the commenters that our modeling should reflect Congress' decision
regarding the EPA waiver for the ACT regulation and therefore we have
completely removed California's ACT regulation from the modeling for
the final action analysis.
We received conflicting comments related to consumer interest in
EVs. Some stated that EV market share is and will be lower in the
future than the EPA estimated in the 2024 GHG Emission Standards Rules
and in the proposal. The main reasons cited by commenters were the
passage of the OBBB and subsequent removal of IRA purchase and leasing
tax credits leading to higher cost for consumers, the CRA resolution
nullifying California's CAA preemption waiver for the Advanced Clean
Cars (ACC) II regulation leading to decreased demand, and slower
charging infrastructure development than estimated in the 2024 GHG
Emission Standards Rules. On the other hand, some commenters stated
that consumer demand for EVs is strong and growing, that states
continue to provide incentives for EV purchases, and that there are
continued strong investments in EV charging networks. After
consideration of the comments, our assessment is that there is a
reduced consumer interest in purchasing EVs overall. Therefore, we
lowered the BEV acceptance parameter values in our modeling of this
final action from those presented in the proposal.
Some commenters criticized the EPA's analysis in the DRIA for
including a scenario that they characterized as using arbitrarily low
fuel prices, citing the scenario with gasoline prices set at $1 and
$0.25 per gallon less than the Energy Information Administration's
(EIA) Annual Energy Outlook (AEO) 2023 Reference case for gasoline and
diesel, respectively. Commenters stated that EIA's AEO 2025 projections
included an Alternative Transportation case that reflects many of the
changes that are occurring in the transportation sector, including the
removal of California's ACT, the EPA's 2024 GHG Emission Standards
Rules, and NHTSA's 2024 final rule for CAFE standards for MYs 2027-
2032, as well as assuming a slower growth for IRA credit eligibility
than assumed in the AEO 2025 Reference case. We agree that the
Alternative Transportation case energy prices are appropriate to use in
our modeling for the case where the standards are removed, and we
included it in our modeling for the final action. We also have revised
the low gasoline and diesel price scenario; instead of using a $1 or
$0.25 per gallon across-the-board decrease, we use prices from the Low
Oil Price case presented in AEO 2025. In summary, the modeling we
conducted for the final action includes future gasoline, diesel,
electricity, and hydrogen prices that reflect EIA's AEO 2025
projections of the Reference, Alternative Transportation, and Low Oil
Price cases.
In the RIA, the EPA presents results from four scenarios using the
same analytical methods the EPA used in the 2024 GHG Emission Standards
Rules that project the costs and benefits from removing the GHG
standards for LD, MD and HD vehicles and HD engines. The results of
these scenarios are summarized in Table 13 and Table 14. Except as
noted this section VIII.A, and as discussed in the RIA, the models,
assumptions and inputs are the same as those used in the 2024 RIAs.
The first scenario (A1) includes the revisions noted above,
including the use of AEO 2025 Reference case fuel prices for the
modeling of the no action case where the GHG standards remain in place,
and the AEO 2025 Alternative Transportation fuel prices for modeling
the action case where the GHG standards are removed. Recognizing the
uncertainties related to projecting future gasoline and diesel prices,
the second scenario (A2) considers the impacts under lower fuel prices,
and uses AEO 2025's Low Oil Price case.
In the NPRM, the EPA presented two scenarios accounting for only
the first two and a half years of fuel savings in estimating the net
monetized impact of removing the GHG emission standards. Commenters
suggested the Agency's adjustment was arbitrary and unsupported. Some
commenters stated that the savings that accrue after the first two and
a half years are a real-world benefit to consumers and society and
therefore should be included in the benefit-cost assessment. Other
commenters stated that the EPA should account for more than the first
two and a half years of fuel savings but should not account for the
full lifetime of fuel savings. The Agency also received comments that
the approach of only including the first two and a half years of fuel
savings was specifically not appropriate to apply to HD vehicles
because they are for-profit businesses that account for fuel and
maintenance savings when making purchasing decisions. For the final
action, we continue to present results representing both a full
lifetime of fuel savings (scenarios A1 and A2) and only the first two
and a half years of fuel savings. The third (A3) and fourth (A4)
scenarios build on the first and second scenarios respectively,
accounting for only the first two and a half years of fuel savings in
estimating the net monetized impacts of this action. The EPA believes
the presented results provide reasonable bounds for the impact of fuel
savings on the net monetized impacts of this action. Table 13 and Table
14 show the net present value of the monetized savings, costs, and net
savings of the four scenarios presented at 7 and 3 percent discount
rates, respectively.
[[Page 7755]]
[GRAPHIC] [TIFF OMITTED] TR18FE26.015
[GRAPHIC] [TIFF OMITTED] TR18FE26.016
In Tables 15 and 16 we provide the estimated cost savings per
vehicle at a seven percent net present value and a three percent net
present value. As shown in the tables, the EPA's modeling projects this
rule to result in about 469 million new combined LD, MD, and HD vehicle
sales over the 2027 to 2055 time period under Scenarios A1 and A3, and
about 472 million new combined LD, MD, and HD vehicle sales under
Scenarios A2 and A4. With the estimated $730 billion reduction in
vehicle technology cost at a seven percent discount rate, we estimate
this action will result in an average cost reduction of $1,550 per
vehicle under Scenarios A1 and A3. Under Scenarios A2 and A4 at a seven
percent discount rate, the reduction in vehicle technology cost of
about $750 billion are estimated to result in an average cost reduction
of $1,600 per vehicle. With the estimated $1.09 trillion reduction in
vehicle technology cost at a three percent discount rate for Scenarios
A1 and A3, we estimate this action will result in an average cost
reduction of $2,330 per vehicle. Under Scenarios A2 and A4 at a seven
percent discount rate, the reduction in vehicle technology cost of
about $1.14 trillion at a three percent discount rate are estimated to
result in an average cost reduction of $2,420 per vehicle.
[[Page 7756]]
[GRAPHIC] [TIFF OMITTED] TR18FE26.017
[GRAPHIC] [TIFF OMITTED] TR18FE26.018
Table 17 provides the GHG emission impacts in calendar year (CY)
2055 by emission source due to this action. For motor vehicles, total
GHG emissions increase by 410 million metric tons (MMT) in carbon
dioxide equivalent (CO2e). Table 18 provides the cumulative
GHG emissions impact from CY 2027 through CY 2055. The total GHG
emissions are estimated to increase by 8,300 MMT CO2e.
[GRAPHIC] [TIFF OMITTED] TR18FE26.019
[[Page 7757]]
[GRAPHIC] [TIFF OMITTED] TR18FE26.020
The EPA discussed air pollutants not being directly impacted by
this rule (i.e., criteria pollutants and hazardous air pollutants)
within other documents within the docket. The EPA is obligated to
ensure the public is not misled regarding the level of scientific
understanding and the implications of that science when developing
policies and regulations. Historically, however, the EPA's analytical
practices often provided the public with false precision and confidence
regarding the monetized impacts of fine particulate matter
(PM2.5) and ozone than the underlying science could fully
support, especially as overall emissions have significantly decreased
and impacts have become more uncertain. The EPA's use of benefit per
ton (BPT) monetized values introduces additional uncertainty. Although
intended as a screening tool when full-form photochemical modeling was
not feasible, the BPT approach reduces complex spatial and atmospheric
relationships into an average value per ton, which magnifies
uncertainty in the resulting monetized estimates. Examples of
uncertainties include but are not limited to epidemiological
uncertainty (e.g., concentration-response functions); economic factors
(e.g., discount rates, income growth, willingness-to-pay to avoid
mortality risk); and methodological assumptions (e.g., health
thresholds, linear relationships, spatial relationships).
Despite these uncertainties, the EPA historically provided point
estimates instead of just ranges or only quantifying emissions, which
leads the public to believe the Agency has a better understanding of
the monetized impacts of exposure to PM2.5 and ozone than it
does in reality. Therefore, to rectify this error, the EPA is no longer
monetizing benefits from PM2.5 and ozone but will continue
to quantify the emissions until the Agency is confident enough in the
modeling to properly monetize those impacts.
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
This action is an E.O. 14192 deregulatory action. For E.O. 14192
regulatory accounting, the estimated present value and annualized value
of the cost savings of this action are $769 billion and $54 billion,
respectively (7 percent discount rate, 2024 dollars, 2024 present value
year, perpetuity time horizon).\224\ OMB's guidance on implementing
E.O. 14192 (M-25-20) requires that estimates of costs or cost savings
cover the full duration of the expected effects of the action. In some
cases, that may require projecting costs or cost savings beyond the
standard analytic time horizon. For this action, the EPA extrapolates
the stream of cost savings based on the final year of the modeling as a
proxy for the long-run effects of this action on the vehicle fleet. A
summary of the projected cost savings can be found in the RIA.
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\224\ The supporting documentation on how these values were
estimates can be found in the Vehicle Rule FRM E.O. 14192
Workbook.xlsx file found in the docket for this action.
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C. Paperwork Reduction Act (PRA)
The information collection activities in this action have been
submitted for approval OMB under the PRA. The Information Collection
Requests (ICR) that the EPA prepared have been assigned numbers as
indicated below. You can find a copy of the Supporting Statements in
the docket for this action, and they are briefly summarized here.
An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for the
EPA's regulations in Title 40 of the CFR are listed in 40 CFR part 9.
When OMB approves this ICR, the Agency will announce that approval in
the Federal Register and publish a technical amendment to 40 CFR part 9
to display the OMB control number for the approved information
collection activities contained in this final action.
1. 2024 LD and MD Multi-Pollutant Emission Standards Rule
The ICR document prepared by the EPA for removal of the light- and
medium-duty vehicle GHG requirements has been assigned EPA ICR 2750.03,
revising EPA ICR 2750.02 (OMB 2060-0764). You can find a copy of the
ICR in the docket for this action and it is briefly summarized here.
The information collection requirements are not enforceable until OMB
approves them.
The EPA is removing all regulations that require light- and medium-
duty vehicle manufacturers to measure, report, or comply with standards
for GHG emissions. Information collected to assure compliance with
those requirements is no longer needed under this final action. All
other requirements covered by 2750.02 remain in effect.
Respondents/affected entities: Light- and medium-duty vehicle
manufacturers, alternative fuel converters, and independent commercial
importers.
Respondent's obligation to respond: This action relieves
manufacturers of the burden to provide certain information to the EPA
as part of their annual MY vehicle certification under CAA section
208(a), which is required prior to entering vehicles into commerce.
Participation in some programs is voluntary; but once a manufacturer
has elected to participate, it must submit the required information.
Estimated number of respondents: 35 affected entities.
Frequency of response: Annually or on occasion, depending on the
type of response.
Revised total estimated burden: 138,443 hours (per year) for
remaining regulatory requirements covered by this ICR. Burden is
defined at 5 CFR 1320.3(b).
Revised total estimated cost: $26.3 million per year for remaining
regulatory requirements covered by this ICR, which includes an
estimated $14.2 million annualized capital or operation and maintenance
costs.
2. 2024 HD GHG Emission Standards Rule
The ICR document prepared by the EPA for removal of the 2024 HD GHG
Emission Standards Rule requirements has been assigned EPA ICR 2734.03,
revising EPA ICR 2734.02 (OMB 2060-0753). You can find a copy of the
ICR in the docket for this action and it is briefly summarized here.
The information collection requirements are
[[Page 7758]]
not enforceable until OMB approves them.
The EPA is removing all regulations that require HD motor vehicle
and HD motor vehicle engine manufacturers to measure, report, or comply
with the 2024 HD GHG Emission Standards Rule standards. Information
collected to assure compliance with those requirements is no longer
needed under this final action.
Respondents/affected entities: Manufacturers of HD onroad vehicles.
Respondent's obligation to respond: This action relieves
manufacturers of the burden to provide certain information to the EPA
as part of their annual MY engine and vehicle certification under CAA
section 203(a), which is required prior to entering vehicles into
commerce.
Estimated number of respondents: 77 affected entities.
Frequency of response: Originally expected to be one-time burden;
now, no requirement to report.
Revised total estimated burden: 0 hours. Burden is defined at 5 CFR
1320.03(b).
Revised total estimated cost: $0.
3. Nonroad Compression-Ignition Engines and On-Highway Heavy-Duty
Engines, Supporting Statement for Information Collection Request (March
2023 Revision)
We are not acting on the proposed changes to this ICR document to
ensure this ICR will continue to cover the information collection
necessary to implement NHTSA's MD and HD fuel efficiency program. The
proposed changes to the ICR document can be found at EPA ICR 1684.22,
revising EPA ICR 1684.21 (OMB 2060-0287).
The EPA is not acting on these revisions as they are no longer
needed. As explained elsewhere in this preamble, in this final action
we are not changing elements of the regulations that are necessary for
programs unrelated to the GHG emission standards, including emission
standards for criteria pollutants. We also are retaining most of the
regulatory provisions cited by NHTSA for the administration of their
fuel efficiency standards included in 49 CFR part 535. This includes
the provisions that require manufacturers to submit their compliance
data and information to the EPA and we will then issue a report to
NHTSA with the information. However, we note that the EPA would no
longer issue EPA certificates of conformity for GHG emissions.
D. Regulatory Flexibility Act (RFA)
I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. In
making this determination, the EPA concludes that the impact of concern
for this action is any significant adverse economic impact on small
entities, and that the Agency is certifying that this action will not
have a significant economic impact on a substantial number of small
entities because the action relieves regulatory burden on the small
entities subject to the action.
The regulated entities that are subject to the regulations we are
removing in this action are engine and vehicle manufacturers,
alternative fuel converters, and independent commercial importers
subject to GHG emission standards for vehicles. The Agency is
certifying that this action will not have a significant economic impact
on a substantial number of small entities because the action will
relieve regulatory burden on all entities, including all small
entities, subject to the current rules. This action removes portions of
the regulations of the standard-setting parts directly related to GHG
emission standards and compliance provisions for implementing the EPA's
GHG engine and vehicle programs. We do not anticipate that there will
be any significant adverse economic impact on directly regulated small
entities as a result of these revisions. We have therefore concluded
that this action will relieve regulatory burden for all directly
regulated small entities. The EPA provides additional information on
the RFA in chapter 7 of the RIA and in the Response to Comments for
this final action.
E. Unfunded Mandates Reform Act (UMRA)
This action does not contain an unfunded mandate of $100 million
(adjusted annually for inflation) or more (in 1995 dollars) as
described in UMRA, 2 U.S.C. 1531-38, and does not significantly or
uniquely affect small governments. The action imposes no enforceable
duty on any state, local, or Tribal governments, and relieves duties
with respect to the private sector.
F. Executive Order 13132: Federalism
This action does not have federalism implications as specified in
E.O. 13132. It does not have substantial direct effects on the states,
on the relationship between the national government and the states, or
on the distribution of power and responsibilities among the various
levels of government.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
This action does not have Tribal implications as specified in E.O.
13175, entitled ``Consultation and Coordination with Indian Tribal
Governments'' (65 FR 67249, Nov. 9, 2000). It does not have substantial
direct effects on Tribal governments, on the relationship between the
Federal government and Indian Tribes, or on the distribution of power
and responsibilities between the Federal government and Indian Tribes,
as specified in E.O. 13175. Thus, E.O. 13175 does not apply to this
action.
However, consistent with the EPA Policy on Consultation with Indian
Tribes, the EPA initiated a Tribal consultation and coordination
process after proposing this action by sending a ``Notification of
Consultation and Coordination'' letter, dated July 29, 2025, to all 574
Federally recognized Tribes. The letter invited Tribal leaders and
designated consultation representatives to participate in the Tribal
consultation and coordination process. The Nez Perce Nation,
Confederated Tribes of Grand Ronde, Snoqualmie Tribe, and Pueblo of San
Felipe requested to consult with the EPA. The EPA consulted with
officials of these Tribes to permit meaningful and timely input during
the development of this action. A summary of that consultation is
provided in the Response to Comments document for this final action.
H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
E.O. 13045 directs Federal agencies to include an evaluation of the
health and safety effects of the planned regulation on children in
Federal health and safety standards and explain why the regulation is
preferable to potentially effective and reasonably feasible
alternatives. This action is subject to the E.O. because it is an
economically significant regulatory action under E.O. 12866, and the
EPA believes the environmental health or safety risks may have a
disproportionate effect on children, although as explained in the
preamble eliminating all GHG emissions from all vehicles would have a
de minimis impact on public health or welfare. The 2021 Policy on
Children's Health also applies to this action.\225\
---------------------------------------------------------------------------
\225\ U.S. Environmental Protection Agency. (2021). 2021 Policy
on Children's Health: https://www.epa.gov/system/files/documents/2021-10/2021-policy-on-childrens-health.pdf.
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[[Page 7759]]
Although the GHG emissions at issue in this rulemaking do not have
direct impacts on human health, we acknowledge the possibility that
this action could impact emissions of criteria pollutants and air
toxics. Children are not expected to experience greater ambient
concentrations of air pollutants than the general population.
Additionally, as discussed in the preamble, there are safety benefits
from this final action that would benefit children as they are more
susceptible to grievous injuries from less safe motor vehicles.
We note that, as explained above, this action would not impact
separate emission standards for criteria pollutants by the EPA or
separate standards set by NHTSA. At this time, the EPA does not believe
that the action would have a material adverse impact on the health of
individuals with respect to non-GHG air pollutants, including on
children, because the EPA anticipates that the impacts of repealing GHG
emission regulations would have only marginal and incidental impacts on
the emission of non-GHG air pollutants. Potential health impacts of
such air pollutants will continue to be controlled through direct
emissions limits and several other programs that target regional and
national air quality, including the NAAQS program.
I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
This action, which is a significant regulatory action under E.O.
12866, would have a significant effect on the supply, distribution or
use of energy. The EPA has prepared a Statement of Energy Effects for
this action as follows.
This action removes the GHG emission standards and related
compliance provisions for light-, medium-, and heavy-duty engines and
vehicles. This action will result in fewer electric vehicles and more
ICE vehicles produced, as discussed in the RIA, and therefore an
estimated increase in the consumption of petroleum and an estimated
reduction in the consumption of electricity.
J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR
Part 51
This action involves technical standards. However, the changes to
the regulation include removing GHG emission standards and the
corresponding measurement and compliance procedures, some of which also
involve removing existing references to voluntary consensus standards
and other technical standards. This action does not include any new
requirements or new references to technical standards.
The following standards appear in the amendatory text of this
document and were previously approved for the locations in which they
appear: 13 CCR 1968.2, 13 CCR 1971.1, ASTM D1945, SAE J1711 FEB2023,
SAE J1979-2, GEM version 2.0.1, GEM Phase 2, Version 3.0, GEM Phase 2,
Version 3.5.1, GEM Phase 2, Version 4.0, GEM HIL model 3.8.
K. Congressional Review Act (CRA)
This action is subject to the CRA, and the EPA will submit a rule
report to each House of the Congress and to the Comptroller General of
the United States. This action meets the criteria set forth in 5 U.S.C.
804(2).
List of Subjects
40 CFR Part 85
Confidential business information, Greenhouse gases, Imports,
Labeling, Motor vehicle pollution, Reporting and recordkeeping
requirements, Research warranties.
40 CFR Part 86
Environmental protection, Administrative practice and procedure,
Confidential business information, Incorporation by reference,
Labeling, Motor vehicle pollution, Reporting and recordkeeping
requirements.
40 CFR Part 600
Environmental protection, Administrative practice and procedure,
Electric power, Fuel economy, Greenhouse gases, Incorporation by
reference, Labeling, Reporting and recordkeeping requirements.
40 CFR Part 1036
Environmental protection, Administrative practice and procedure,
Air pollution control, Confidential business information, Greenhouse
gases, Incorporation by reference, Labeling, Motor vehicle pollution,
Reporting and recordkeeping requirements, Warranties.
40 CFR Part 1037
Environmental protection, Administrative practice and procedure,
Air pollution control, Confidential business information, Incorporation
by reference, Labeling, Motor vehicle pollution, Reporting and
recordkeeping requirements, Warranties.
40 CFR Part 1039
Administrative practice and procedure, Air pollution control,
Confidential business information, Imports, Labeling, Penalties,
Reporting and recordkeeping requirements, Warranties.
Lee Zeldin,
Administrator.
For the reasons set out in the preamble, we are amending title 40,
chapter I of the Code of Federal Regulations as set forth below.
PART 85--CONTROL OF AIR POLLUTION FROM MOBILE SOURCES
0
1. The authority citation for part 85 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
Sec. 85.525 [Amended]
0
2. Amend Sec. 85.525 by removing and reserving paragraph (b).
0
3. Amend Sec. 85.1515 by revising paragraph (d) to read as follows:
Sec. 85.1515 Emission standards and test procedures applicable to
imported nonconforming motor vehicles and motor vehicle engines.
* * * * *
(d) An ICI may not certify using nonconformance penalties.
Sec. 85.1803 [Amended]
0
4. Amend Sec. 85.1803 by removing paragraph (e).
Sec. 85.1805 [Amended]
0
5. Amend Sec. 85.1805 by removing and reserving paragraph (b).
0
6. Amend Sec. 86.1902 by removing and reserving paragraph (b)(2) and
revising paragraph (d). The revision reads as follows:
Sec. 85.1902 Definitions.
* * * * *
(d) Voluntary emissions recall means a repair, adjustment, or
modification program voluntarily initiated and conducted by a
manufacturer to remedy any emission-related defect for which direct
notification of vehicle or engine owners has been provided.
* * * * *
0
7. Amend Sec. 85.2103 by revising paragraph (d)(1)(v) and removing
paragraph (d)(3). The revision reads as follows:
Sec. 85.2103 Emission warranty.
* * * * *
(d) * * *
(1) * * *
(v) Batteries serving as a Renewable Energy Storage System for
electric vehicles and plug-in hybrid electric vehicles, along with all
components needed to charge the system, store energy, and transmit
power to move the
[[Page 7760]]
vehicle. This paragraph (d)(1)(v) is optional before model year 2027
for light-duty vehicles and light-duty trucks at or below 6,000 pounds
GVWR. This paragraph (d)(1)(v) is optional for vehicles above 6,000
pounds GVWR until they are first certified to Tier 4
NMOG+NOX bin standards under 40 CFR 86.1811-27(b), not later
than model year 2031.
* * * * *
PART 86--CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES
AND ENGINES
0
8. The authority citation for part 86 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
Sec. 86.1 [Amended]
0
9. Amend Sec. 86.1 by removing and reserving paragraphs (c)(2) and (3)
and (f)(3), (17), (21), and (22) and removing paragraph (h).
0
10. Amend Sec. 86.007-11 by revising paragraphs (g)(1) and (6) to read
as follows:
Sec. 86.007-11 Emission standards and supplemental requirements for
2007 and later model year diesel heavy-duty engines and vehicles.
* * * * *
(g) * * *
(1) The engines must be of a configuration that is identical to one
that is certified under 40 CFR part 1039, and must be certified with a
Family Emission Limit for PM of 0.020 g/kW-hr using the same duty
cycles that apply under 40 CFR part 1039.
* * * * *
(6) Engines certified under this paragraph (g) may not generate or
use emission credits under this part or under 40 CFR part 1039.
* * * * *
0
11. Amend Sec. 86.008-10 by revising paragraph (g)(6) to read as
follows:
Sec. 86.008-10 Emission standards for 2008 and later model year Otto-
cycle heavy-duty engines and vehicles.
* * * * *
(g) * * *
(6) Engines certified under this paragraph (g) may not generate or
use emission credits under this part.
* * * * *
0
12. Amend Sec. 86.1801-12 by:
0
a. Removing and reserving paragraph (a)(2)(ii)(B);
0
b. Revising paragraphs (a)(3), (b), and (i); and
0
c. Removing paragraphs (j) and (k).
The revisions read as follows:
Sec. 86.1801-12 Applicability.
(a) * * *
(3) The provisions of this subpart do not apply to heavy-duty
vehicles above 14,000 pounds GVWR (see Sec. 86.016-1 and 40 CFR parts
1036 and 1037), except as follows:
(i) Heavy-duty vehicles above 14,000 pounds GVWR and at or below
19,500 pounds GVWR may be optionally certified to the exhaust emission
standards in this subpart if they are properly included in a test group
with similar vehicles at or below 14,000 pounds GVWR. Emission
standards apply to these vehicles as if they were Class 3 medium-duty
vehicles.
(ii) [Reserved]
(iii) Evaporative and refueling emission standards apply for heavy-
duty vehicles above 14,000 pounds GVWR as specified in 40 CFR 1037.103.
(4) If you optionally certify vehicles to standards under this
subpart, those vehicles are subject to all the regulatory requirements
as if the standards were mandatory.
(b) Relationship to 40 CFR parts 1036 and 1037. If any heavy-duty
vehicle is not subject to standards and certification requirements
under this subpart, the vehicle and its installed engine are instead
subject to standards and certification requirements under 40 CFR parts
1036 and 1037, as applicable. If you optionally certify engines or
vehicles to standards under 40 CFR part 1036 or 40 CFR part 1037,
respectively, those engines or vehicles are subject to all the
regulatory requirements in 40 CFR parts 1036 and 1037 as if they were
mandatory.
* * * * *
(i) Types of pollutants. Criteria pollutant standards apply for
NOX, NMOG, HC, formaldehyde, PM, and CO, including exhaust,
evaporative, and refueling emission standards. These pollutants are
sometimes described collectively as ``criteria pollutants'' because
they are either criteria pollutants under the Clean Air Act or
precursors to the criteria pollutants ozone and PM.
0
13. Amend Sec. 86.1803-01 by:
0
a. Removing the definitions of ``AC1'', ``AC2'', ``Air Conditioning
Idle Test'', ``Base level'', ``Base tire'', ``Base vehicle'',
``Combined CO2'', ``Combined CREE'', and ``Configuration'';
0
b. Revising the definition of ``Defeat device'';
0
c. Removing and reserving paragraph (1) of the definition of
``Emergency vehicle'';
0
d. Revising the definition of ``Engine code'';
0
e. Removing the definition of ``Footprint'', ``Full size pickup
truck'', ``Mild hybrid electric vehicle'', ``Strong hybrid electric
vehicle'', ``Subconfiguration'', ``Track width'', and ``Transmission
class''; and
0
f. Adding a definition of ``Work factor'' in alphabetical order.
The revisions and addition read as follows:
Sec. 86.1803-01 Definitions.
* * * * *
Defeat device means an auxiliary emission control device (AECD)
that reduces the effectiveness of the emission control system under
conditions which may reasonably be expected to be encountered in normal
vehicle operation and use, unless:
(1) Such conditions are substantially included in driving cycles
specified in this subpart or the fuel economy test procedures in 40 CFR
part 600;
(2) The need for the AECD is justified in terms of protecting the
vehicle against damage or accident;
(3) The AECD does not go beyond the requirements of engine
starting; or
(4) The AECD applies only for emergency vehicles and the need is
justified in terms of preventing the vehicle from losing speed, torque,
or power due to abnormal conditions of the emission control system, or
in terms of preventing such abnormal conditions from occurring, during
operation related to emergency response. Examples of such abnormal
conditions may include excessive exhaust backpressure from an
overloaded particulate trap, and running out of diesel exhaust fluid
for engines that rely on urea-based selective catalytic reduction.
* * * * *
Engine code means a unique combination within a test group of
displacement, fuel injection (or carburetor) calibration, choke
calibration, distributor calibration, auxiliary emission control
devices, and other engine and emission control system components
specified by the Administrator. For electric vehicles, engine code
means a unique combination of manufacturer, electric traction motor,
motor configuration, motor controller, and energy storage device.
* * * * *
Work factor, WF, means the characteristic value representing a
vehicle's work potential, calculated to the nearest pound using the
following equation:
WF = 0.75 x (GVWR - Curb Weight + xwd) + 0.25 x (GCWR - GVWR)
Where:
xwd = 500 pounds if the vehicle has four-wheel drive or all-wheel
drive; xwd = 0 pounds for all other vehicles.
[[Page 7761]]
* * * * *
0
14. Amend Sec. 86.1805-12 by revising paragraph (a) to read as
follows:
Sec. 86.1805-12 Useful life.
(a) Except as permitted under paragraph (b) of this section or
required under paragraphs (c) and (d) of this section, the full useful
life for all LDVs and LLDTs is a period of use of 10 years or 120,000
miles, whichever occurs first. The full useful life for all HLDTs,
MDPVs, and complete heavy-duty vehicles is a period of 11 years or
120,000 miles, whichever occurs first. These full useful life values
apply to all exhaust, evaporative and refueling emission requirements
except for standards which are specified to only be applicable at the
time of certification.
* * * * *
0
15. Revise Sec. 86.1805-17 to read as follows:
Sec. 86.1805-17 Useful life.
(a) General provisions. The useful life values specified in this
section apply for all exhaust, evaporative, refueling, and OBD emission
requirements described in this subpart, except for standards that are
specified to apply only at certification. Useful life values are
specified as a given number of calendar years or miles of driving,
whichever comes first.
(b) [Reserved]
(c) Cold temperature emission standards. The cold temperature NMHC
emission standards in Sec. 86.1811-17 apply for a useful life of 10
years or 120,000 miles for LDV and LLDT, and 11 years or 120,000 miles
for HLDT and HDV. The cold temperature CO emission standards in Sec.
86.1811-17 apply for a useful life of 5 years or 50,000 miles.
(d) Criteria pollutants. The useful life provisions of this
paragraph (d) apply for all emission standards not covered by paragraph
(c) of this section. This paragraph (d) applies for the cold
temperature emission standards in Sec. 86.1811-27(c). Except as
specified in paragraph (f) of this section and in Sec. Sec. 86.1811,
86.1813, and 86.1816, the useful life for LDT2, HLDT, MDPV, and HDV is
15 years or 150,000 miles. The useful life for LDV and LDT1 is 10 years
or 120,000 miles. Manufacturers may optionally certify LDV and LDT1 to
a useful life of 15 years or 150,000 miles, in which case the longer
useful life would apply for all the standards and requirements covered
by this paragraph (d).
(e) Intermediate useful life. Where exhaust emission standards are
specified for an intermediate useful life, these standards apply for
five years or 50,000 miles.
0
16. Amend Sec. 86.1806-27 by adding paragraphs (a)(9) through (13) to
read as follows:
Sec. 86.1806-27 Onboard diagnostics.
* * * * *
(a) * * *
(9) The definition of ``Active Off-Cycle Credit Technology'' in 13
CCR 1968.2(c) does not apply.
(10) The vehicle operations and control strategies standardization
requirements in 13 CCR 1968.2 (g)(6.3), (6.4), (6.5), (6.8), (6.9),
(6.10), and (6.11) do not apply.
(11) The data reporting and storage requirements in 13 CCR
1968.2(h)(6.1) related to the standardization requirements in 13 CCR
1968.2(g)(8.1) do not apply.
(12) The certification documentation requirement related to
``Active Off-Cycle Credit Technologies'' in 13 CCR 1968.2(i)(2.28) does
not apply.
(13) The monitoring system demonstration requirements in 13 CCR
1968.2(h)(5.3.1)(D) and (5.3.2)(A)(iii) related to CO2
emission data does not apply.
* * * * *
Sec. 86.1807-01 [Amended]
0
17. Amend Sec. 86.1807-01 By Removing And Reserving Paragraph
(A)(3)(IV).
0
18. Amend Sec. 86.1809-12 by revising paragraph (d)(1) to read as
follows:
Sec. 86.1809-12 Prohibition of defeat devices.
* * * * *
(d) * * *
(1) The manufacturer must show to EPA's satisfaction that the
vehicle design does not incorporate strategies that unnecessarily
reduce emission control effectiveness exhibited over the driving cycles
specified in this subpart or the fuel economy test procedures in 40 CFR
part 600 when the vehicle is operated under conditions that may
reasonably be expected to be encountered in normal operation and use.
* * * * *
0
19. Amend Sec. 86.1810-09 by revising paragraph (f)(2) to read as
follows:
Sec. 86.1810-09 General standards; increase in emissions; unsafe
condition; waivers.
* * * * *
(f) * * *
(2) For vehicles that comply with the cold temperature NMHC
standards described in Sec. 86.1811-10(g), manufacturers must submit
an engineering evaluation indicating that common calibration approaches
are utilized at high altitudes (except when there are specific high
altitude calibration needs to deviate from low altitude emission
control practices). Any deviation from low altitude emission control
practices must be included in the auxiliary emission control device
(AECD) descriptions submitted at certification. Any AECD specific to
high altitude must require engineering emission data for EPA evaluation
to quantify any emission impact and validity of the AECD.
* * * * *
0
20. Amend Sec. 86.1810-17 by revising paragraph (j) to read as
follows:
Sec. 86.1810-17 General requirements.
* * * * *
(j) Small-volume manufacturers that modify a vehicle already
certified by a different company may recertify that vehicle under this
subpart S based on the vehicle supplier's compliance with fleet average
standards for criteria exhaust emissions and evaporative emissions as
follows:
(1) The recertifying manufacturer must certify the vehicle at bin
levels and family emission limits that are the same as or more
stringent than the corresponding bin levels and family emission limits
for the vehicle supplier.
(2) The recertifying manufacturer must meet all the standards and
requirements described in this subpart S, except for the fleet average
standards for criteria exhaust emissions and evaporative emissions.
(3) The vehicle supplier must send the small-volume manufacturer a
written statement accepting responsibility to include the subject
vehicles in the vehicle supplier's exhaust and evaporative fleet
average calculations in Sec. Sec. 86.1860-17 and 86.1864-10.
(4) The small-volume manufacturer must describe in the application
for certification how the two companies are working together to
demonstrate compliance for the subject vehicles. The application must
include the statement from the vehicle supplier described in paragraph
(j)(3) of this section.
(5) The vehicle supplier must include a statement that the vehicle
supplier is including the small volume manufacturer's sales volume and
emissions levels in the vehicle supplier's fleet average reports under
Sec. Sec. 86.1860-17 and 86.1864-10.
* * * * *
0
21. Amend Sec. 86.1811-17 by revising paragraph (a) to read as
follows:
[[Page 7762]]
Sec. 86.1811-17 Exhaust emission standards for light-duty vehicles,
light-duty trucks and medium-duty passenger vehicles.
(a) Applicability and general provisions. This section describes
exhaust emission standards that apply for model year 2017 and later
light-duty vehicles, light-duty trucks, and medium-duty passenger
vehicles. MDPVs are subject to all the same emission standards and
certification provisions that apply to LDT4. Some of the provisions of
this section also apply to heavy-duty vehicles as specified in Sec.
86.1816. See Sec. 86.1813 for evaporative and refueling emission
standards. This section may apply to vehicles from model years earlier
than 2017 as specified in paragraph (b)(11) of this section.
* * * * *
Sec. 86.1811-27 [AMENDED]
0
22. Amend Sec. 86.1811-27 by removing paragraph (a)(4).
Sec. 86.1815-27 [Removed]
0
23. Remove Sec. 86.1815-27.
0
24. Amend Sec. 86.1816-18 by revising paragraph (a) to read as
follows:
Sec. 86.1816-18 Emission standards for heavy-duty vehicles.
(a) Applicability and general provisions. This section describes
Tier 3 exhaust emission standards for complete heavy-duty vehicles.
These standards are optional for incomplete heavy-duty vehicles and for
heavy-duty vehicles above 14,000 pounds GVWR as described in Sec.
86.1801. See Sec. 86.1813 for evaporative and refueling emission
standards. This section starts to apply in model year 2018, except that
the provisions may apply to vehicles before model year 2018 as
specified in paragraph (b)(11) of this section. This section applies
for model year 2027 and later vehicles only as specified in Sec.
86.1811-27. Separate requirements apply for MDPV as specified in Sec.
86.1811. See subpart A of this part for requirements that apply for
incomplete heavy-duty vehicles and for heavy-duty engines certified
independent of the chassis. The following general provisions apply:
(1) Test all vehicles as described in this section using a chassis
dynamometer; establish appropriate load settings based on adjusted
loaded vehicle weight (see Sec. 86.1803).
(2) Some provisions apply differently depending on the vehicle's
power-to-weight ratio. Determine a vehicle's power-to-weight ratio by
dividing the engine's rated power by the vehicle's GVWR (in hp/pound).
For purposes of this section, if a test group includes multiple vehicle
configurations, use the vehicle with the highest power-to-weight ratio
to characterize the test group.
(3) Use E10 test fuel as required in Sec. 86.113, except as
specified in this section.
(4) Measure emissions from hybrid electric vehicles (including
plug-in hybrid electric vehicles) as described in 40 CFR part 1066,
subpart F, except that these procedures do not apply for plug-in hybrid
electric vehicles during charge-depleting operation.
* * * * *
Sec. Sec. 86.1818-12 And 86.1819-14 [Removed]
0
25. Remove Sec. Sec. 86.1818-12 And 86.1819-14.
0
26. Amend Sec. 86.1822-01 by revising paragraph (b) to read as
follows:
Sec. 86.1822--01 Durability data vehicle selection.
* * * * *
(b) The manufacturer may select, using good engineering judgment,
an equivalent or worst-case vehicle configuration in lieu of testing
the vehicle selected in paragraph (a) of this section. Carryover data
satisfying the provisions of Sec. 86.1839-01 may also be used in lieu
of testing the vehicle configuration selected in paragraph (a) of this
section.
Sec. 86.1823-08 [Amended]
0
27. Amend Sec. 86.1823-08 by removing and reserving paragraph (M).
0
28. Amend Sec. 86.1827-01 by revising paragraph (a)(5) to read as
follows:
Sec. 86.1827-01 Test group determination.
* * * * *
(a) * * *
(5) Subject to the same emission standards, or FEL in the case of
cold temperature NMHC or NMOG+NOX standards, except that a
manufacturer may request to group vehicles into the same test group as
vehicles subject to more stringent standards, so long as all the
vehicles within the test group are certified to the most stringent
standards applicable to any vehicle within that test group. For
example, manufacturers may include medium-duty vehicles at or below
22,000 pounds GCWR in the same test group with medium-duty vehicles
above 22,000 pounds GCWR, but all vehicles included in the test group
are then subject to the off-cycle emission standards and testing
requirements described in Sec. 86.1811-27(e). Light-duty trucks and
light-duty vehicles may be included in the same test group if all
vehicles in the test group are subject to the same criteria exhaust
emission standards.
* * * * *
0
29. Amend Sec. 86.1828-01 by revising paragraph (e) to read as
follows:
Sec. 86.1828-01 Emission data vehicle selection.
* * * * *
(e) Alternative vehicle configurations. The manufacturer may use
good engineering judgment to select an equivalent or worst-case vehicle
configuration in lieu of testing the vehicle selected in paragraphs (a)
through (c) of this section. Carryover data satisfying the provisions
of Sec. 86.1839 may also be used in lieu of testing the vehicle
configuration selected in paragraphs (a) through (c) of this section.
* * * * *
0
30. Amend Sec. 86.1829-15 by:
0
a. Removing and reserving paragraph (a)(2).
0
b. Revising paragraph (d)(3); and
0
c. Removing and reserving paragraph (d)(6).
The revisions read as follows:
Sec. 86.1829-15 Durability and emission testing requirements;
waivers.
* * * * *
(d) * * *
(3) Manufacturers may omit PM measurements for fuel economy testing
conducted in addition to the testing needed to demonstrate compliance
with the PM emission standards.
* * * * *
0
31. Amend Sec. 86.1830-01 by revising paragraphs (a)(3) and (c)(2) to
read as follows:
Sec. 86.1830-01 Acceptance of vehicles for emission testing.
(a) * * *
(3) Test vehicles must have air conditioning installed and
operational if that vehicle configuration is available with air
conditioning. Optional equipment must be installed or represented on
test vehicles according to the provisions of Sec. 86.1832-01.
* * * * *
(c) * * *
(2) Within a durability group, the manufacturer may alter any
emission data vehicle (or other vehicles such as current or previous
model year emission data vehicles, running change vehicles, fuel
economy data vehicles, and development vehicles) in lieu of building a
new test vehicle providing that the modification will not impact the
representativeness of the vehicle's test results. Manufacturers shall
use good engineering judgment in making
[[Page 7763]]
such determinations. Development vehicles which were used to develop
the calibration selected for emission data testing may not be used as
the EDV for that vehicle configuration. Vehicles from outside the
durability group may be altered with advance approval of the
Administrator.
* * * * *
0
32. Amend Sec. 86.1835-01 by revising paragraphs (a)(4), (b)(3), and
(c) to read as follows:
Sec. 86.1835-01 Confirmatory certification testing.
(a) * * *
(4) Retesting for fuel economy may be conducted under the
provisions of 40 CFR 600.008-08.
(b) * * *
(3) For light-duty vehicles, light-duty trucks, and medium-duty
passenger vehicles the manufacturer shall conduct a retest of the FTP
or highway test if the difference between the fuel economy of the
confirmatory test and the original manufacturer's test equals or
exceeds three percent (or such lower percentage to be applied
consistently to all manufacturer conducted confirmatory testing as
requested by the manufacturer and approved by the Administrator).
(i) For use in the fuel economy program described in 40 CFR part
600, the manufacturer may, in lieu of conducting a retest, accept as
official the lower of the original and confirmatory test fuel economy
results.
(ii) The manufacturer shall conduct a second retest of the FTP or
highway test if the fuel economy difference between the second
confirmatory test and the original manufacturer test equals or exceeds
three percent (or such lower percentage as requested by the
manufacturer and approved by the Administrator) and the fuel economy
difference between the second confirmatory test and the first
confirmatory test equals or exceeds three percent (or such lower
percentage as requested by the manufacturer and approved by the
Administrator). In lieu of conducting a second retest, the manufacturer
may accept as official (for use in the fuel economy program) the lowest
fuel economy of the original test, the first confirmatory test, and the
second confirmatory test fuel economy results.
(c) Official test determination. (1) Whenever the Administrator or
the manufacturer conducts a confirmatory test segment on a test
vehicle, the results of that test segment, unless subsequently
invalidated by the Administrator, shall comprise the official data for
that test segment for the vehicle at the prescribed test point and the
manufacturer's original test data for that test segment for that
prescribed test point shall not be used in determining compliance with
emission standards.
(i) If the Administrator or the manufacturer conducts more than one
passing, valid, confirmatory test, the results from the first passing,
valid confirmatory test shall be considered official and used in
determining compliance with emission standards.
(ii) Official test results for fuel economy are determined in
accordance with the provisions of Sec. 600.008-08 of this chapter.
(iii) The Administrator may stop a test after any evaporative test
segment and use as official data any valid results obtained up to that
point in the test, as described in subpart B of this part.
(2) Whenever the Administrator or the manufacturer does not conduct
a confirmatory test on a test vehicle at a test point, the
manufacturer's original test data will be accepted as the official data
for that point.
(i) If the Administrator makes a determination based on testing
under paragraph (a) of this section (or other appropriate correlation
test data), that there is a lack of correlation between the
manufacturer's test equipment or procedures and the test equipment or
procedures used by the Administrator, no manufacturer's test data will
be accepted for purposes of certification until the reasons for the
lack of correlation are determined and the validity of the data is
established by the manufacturer.
(ii) If the Administrator has reasonable basis to believe that any
test data submitted by the manufacturer is not accurate or has been
obtained in violation of any provisions of this subpart, the
Administrator may refuse to accept that data as the official data
pending retesting or submission of further information.
(iii) If the manufacturer conducts more than one test on an
emission data vehicle in the same vehicle configuration (excluding
confirmatory tests run under paragraph (b) of this section), the data
from the last test in that series of tests on that vehicle, will
constitute the official data.
* * * * *
Sec. 86.1838-01 [Amended]
0
33. Amend Sec. 86.1838-01 by removing and reserving paragraph
(B)(1)(I)(B).
0
34. Revise Sec. 86.1839-01 to read as follows:
Sec. 86.1839-01 Carryover of certification data.
(a) In lieu of testing an emission-data or durability vehicle
selected under Sec. 86.1822, Sec. 86.1828, or Sec. 86.1829, and
submitting data therefrom, a manufacturer may submit exhaust emission
data, evaporative emission data and/or refueling emission data, as
applicable, on a similar vehicle for which certification has been
obtained or for which all applicable data required under Sec. 86.1845
has previously been submitted. To be eligible for this provision, the
manufacturer must use good engineering judgment and meet the following
criteria:
(1) In the case of durability data, the manufacturer must determine
that the previously generated durability data represent a worst case or
equivalent rate of deterioration for all applicable emission
constituents compared to the vehicle configuration selected for
durability demonstration. Prior to certification, the Administrator may
require the manufacturer to provide data showing that the distribution
of catalyst temperatures of the selected durability vehicle
configuration is effectively equivalent or lower than the distribution
of catalyst temperatures of the vehicle configuration which is the
source of the previously generated data.
(2) In the case of emission data, the manufacturer must determine
that the previously generated emissions data represent a worst case or
equivalent level of emissions for all applicable emission constituents
compared to the vehicle configuration selected for emission compliance
demonstration.
(b) In lieu of using newly aged hardware on an EDV as allowed under
the provisions of Sec. 86.1823-08(f)(2), a manufacturer may use
similar hardware aged for an EDV previously submitted, provided that
the manufacturer determines that the previously aged hardware
represents a worst case or equivalent rate of deterioration for all
applicable emission constituents for durability demonstration.
Sec. 86.1841-01 [Amended]
0
35. Amend Sec. 86.1841-01 by removing and reserving paragraph (A)(3).
0
36. Amend Sec. 86.1844-01 by:
0
a. Removing and reserving paragraph (d)(7)(iv);
0
b. Revising paragraph (d)(15);
0
c. Removing and reserving paragraphs (d)(19) and (20); and
0
d. Revising paragraphs (e)(1) and (3).
The revisions read as follows:
Sec. 86.1844-01 Information requirements: Application for
certification and submittal of information upon request.
* * * * *
(d) * * *
(15) For vehicles with fuel-fired heaters, describe the control
system
[[Page 7764]]
logic of the fuel-fired heater, including an evaluation of the
conditions under which it can be operated and an evaluation of the
possible operational modes and conditions under which evaporative
emissions can exist. Use good engineering judgment to establish an
estimated exhaust emission rate from the fuel-fired heater in grams per
mile for each pollutant subject to a fleet average standard. Adjust
fleet average compliance calculations in Sec. Sec. 86.1861 and 86.1864
as appropriate to account for emissions from fuel-fired heaters.
Describe the testing used to establish the exhaust emission rate.
* * * * *
(e) * * *
(1) Identify all emission-related components. Also identify
software, AECDs, and other elements of design that are used to control
criteria, exhaust or evaporative/refueling emissions. Identify the
emission-related components by part number. Identify software by part
number or other convention, as appropriate. Organize part numbers by
engine code or other similar classification scheme.
* * * * *
(3) Identification and description of all vehicles covered by each
certificate of conformity to be produced and sold within the U.S. The
description must be sufficient to identify whether any given in-use
vehicle is, or is not, covered by a given certificate of conformity,
the test group and the evaporative/refueling family to which it belongs
and the standards that are applicable to it, by matching readily
observable vehicle characteristics and information given in the
emission control information label (and other permanently attached
labels) to indicators in the Part 1 Application. For example, the
description must include any components or features that contribute to
measured or demonstrated control of emissions for meeting criteria
exhaust or evaporative/refueling standards under this subpart. In
addition, the description must be sufficient to determine for each
vehicle covered by the certificate, all appropriate test parameters and
any special test procedures necessary to conduct an official
certification exhaust or evaporative emission test as was required by
this subpart to demonstrate compliance with applicable emission
standards. The description shall include, but is not limited to,
information such as model name, vehicle classification (light-duty
vehicle, light-duty truck, or complete heavy-duty vehicle), sales area,
engine displacement, engine code, transmission type, tire size and
parameters necessary to conduct exhaust emission tests such as
equivalent test weight, curb and gross vehicle weight, test horsepower
(with and without air conditioning adjustment), coast down time, shift
schedules, cooling fan configuration, etc. and evaporative tests such
as canister working capacity, canister bed volume, and fuel temperature
profile. Actual values must be provided for all parameters.
* * * * *
0
37. Amend Sec. 86.1845-04 by:
0
a. Revising paragraphs (b)(5)(i) and (c)(5)(i);
0
b. Removing and reserving paragraph (g); and
0
c. Revising paragraph (h)(6) introductory text.
The revisions read as follows:
Sec. 86.1845-04 Manufacturer in-use verification testing
requirements.
* * * * *
(b) * * *
(5) Testing. (i) Each test vehicle of a test group shall be tested
in accordance with the FTP and the US06 as described in subpart B of
this part, when such test vehicle is tested for compliance with
applicable exhaust emission standards under this subpart.
* * * * *
(c) * * *
(5) Testing. (i) Each test vehicle shall be tested in accordance
with the FTP and the US06 as described in subpart B of this part when
such test vehicle is tested for compliance with applicable exhaust
emission standards under this subpart. One test vehicle from each test
group shall be tested over the FTP at high altitude. The test vehicle
tested at high altitude is not required to be one of the same test
vehicles tested at low altitude. The test vehicle tested at high
altitude is counted when determining the compliance with the
requirements shown in Table S04-06 and Table S04-07 (tables 1 and 2 to
paragraph (b)(3) of this section) or the expanded sample size as
provided for in this paragraph (c).
* * * * *
(h) * * *
(6) Determine a reference CO2 emission rate,
eCO2FTPFCL, as described in 40 CFR 1036.530 or based on
measured values from any chassis FTP driving cycles under 40 CFR part
1066, subpart I, that is used for reporting data from an emission data
vehicle or a fuel economy data vehicle, as follows:
* * * * *
0
38. Amend Sec. 86.1846-01 by:
0
a. Revising paragraph (a); and
0
b. Removing and reserving paragraph (b)(2).
The revision reads as follows:
Sec. 86.1846-01 Manufacturer in-use confirmatory testing
requirements.
(a) General requirements. (1) Manufacturers must test, or cause
testing to be conducted, under this section when the emission levels
shown by a test group sample from testing under Sec. 86.1845 exceeds
the criteria specified in paragraph (b) of this section. The testing
required under this section applies separately to each test group and
at each test point (low and high mileage) that meets the specified
criteria. The testing requirements apply separately for each model
year.
(2) The provisions of Sec. 86.1845-04(a)(3) regarding fuel sulfur
effects apply equally to testing under this section.
* * * * *
Sec. 86.1847-01 [Amended]
0
39. Amend Sec. 86.1847-01 by removing and reserving paragraph (G).
0
40. Amend Sec. 86.1848-10 by:
0
a. Revising paragraphs (c)(2) and (5); and
0
b. Removing paragraphs (c)(9) and (10).
The revisions read as follows:
Sec. 86.1848-10 Compliance with emission standards for the purpose
of certification.
* * * * *
(c) * * *
(2) The manufacturer must comply with all certification and in-use
emission standards contained in this subpart both during and after
model year production.
* * * * *
(5) The manufacturer must meet the in-use testing and reporting
requirements contained in Sec. Sec. 86.1845, 86.1846, and 86.1847, as
applicable.
* * * * *
0
41. Amend Sec. 86.1854-12 by revising paragraph (a)(2)(iv) to read as
follows:
Sec. 86.1854-12 Prohibited acts.
(a) * * *
(2) * * *
(iv) For a person to fail to establish or maintain records as
required under Sec. Sec. 86.1844, 86.1862, and 86.1864 with regard to
vehicles.
* * * * *
0
42. Revise and republish Sec. 86.1861-17 to read as follows:
Sec. 86.1861-17 How do the NMOG + NOX and evaporative emission
credit programs work?
You may use emission credits for purposes of certification to show
compliance with the applicable fleet
[[Page 7765]]
average NMOG+NOX standards from Sec. thnsp;Sec. 86.1811 and
86.1816 and the fleet average evaporative emission standards from Sec.
86.1813 as described in 40 CFR part 1036, subpart H, with certain
exceptions and clarifications as specified in this section. MDPVs are
subject to the same provisions of this section that apply to LDT4.
(a) Calculate emission credits as described in this paragraph (a)
instead of using the provisions of 40 CFR 1036.705. Calculate positive
or negative emission credits relative to the applicable fleet average
standard. Calculate positive emission credits if your fleet average
level is below the standard. Calculate negative emission credits if
your fleet average value is above the standard. Calculate credits
separately for each applicable fleet average standard and calculate
total credits for each averaging set as specified in paragraph (b) of
this section. Convert units from mg/mile to g/mile as needed for
performing calculations. Calculate emission credits using the following
equation, rounded to the nearest whole number:
Equation 1 to Paragraph (a)
Emission credit = Volume [middot] [Fleet average standard-Fleet average
value]
Where:
Emission credit = The positive or negative credit for each discrete
fleet average standard, in units of vehicle-grams per mile for
NMOG+NOx and vehicle-grams per test for evaporative
emissions.
Volume = Sales volume in a given model year from the collection of
test groups or evaporative families covered by the fleet average
value, as described in Sec. 86.1860.
(b) The following restrictions apply instead of those specified in
40 CFR 1036.740:
(1) Except as specified in paragraph (b)(2) of this section,
emission credits may be exchanged only within an averaging set, as
follows:
(i) HDV represent a separate averaging set with respect to all
emission standards.
(ii) Except as specified in paragraph (b)(1)(iii) of this section,
light-duty program vehicles represent a single averaging set with
respect to all emission standards. Note that FTP and SFTP credits for
Tier 3 vehicles are not interchangeable.
(iii) LDV and LDT1 certified to standards based on a useful life of
120,000 miles and 10 years together represent a single averaging set
with respect to NMOG+NOX emission standards. Note that FTP
and SFTP credits for Tier 3 vehicles are not interchangeable.
(iv) The following separate averaging sets apply for evaporative
emission standards:
(A) LDV and LDT1 together represent a single averaging set.
(B) LDT2 represents a single averaging set.
(C) HLDT represents a single averaging set.
(D) HDV represents a single averaging set.
(2) You may exchange evaporative emission credits across averaging
sets as follows if you need additional credits to offset a deficit
after the final year of maintaining deficit credits as allowed under
paragraph (c) of this section:
(i) You may exchange LDV/LDT1 and LDT2 emission credits.
(ii) You may exchange HLDT and HDV emission credits.
(3) Except as specified in paragraph (b)(4) of this section,
credits expire after five years. For example, credits you generate in
model year 2018 may be used only through model year 2023.
(4) For the Tier 3 declining fleet average FTP and SFTP emission
standards for NMOG+NOX described in Sec. 86.1811-17(b)(8),
credits generated in model years 2017 through 2024 expire after eight
years, or after model year 2030, whichever comes first; however, these
credits may not be traded after five years. This extended credit life
also applies for small-volume manufacturers generating credits under
Sec. 86.1811-17(h)(1) in model years 2022 through 2024. Note that the
longer credit life does not apply for heavy-duty vehicles, for vehicles
certified under the alternate phase-in described in Sec. 86.1811-
17(b)(9), or for vehicles generating early Tier 3 credits under Sec.
86.1811-17(b)(11) in model year 2017.
(5) Tier 3 credits for NMOG+NOX may be used to
demonstrate compliance with Tier 4 standards without adjustment, except
as specified in Sec. 86.1811-27(b)(6)(ii).
(6) A manufacturer may generate NMOG+NOX credits from
model year 2027 through 2032 electric vehicles that qualify as MDPV and
use those credits for certifying medium-duty vehicles, as follows:
(i) Calculate generated credits separately for qualifying vehicles.
Calculate generated credits by multiplying the applicable standard for
light-duty program vehicles by the sales volume of qualifying vehicles
in a given model year.
(ii) Apply generated credits to eliminate any deficit for light-
duty program vehicles before using them to certify medium-duty
vehicles.
(iii) Apply the credit provisions of this section as specified,
except that you may not buy or sell credits generated under this
paragraph (b)(6).
(iv) Describe in annual credit reports how you are generating
certain credit quantities under this paragraph (b)(6). Also describe in
your end of year credit report how you will use those credits for
certifying light-duty program vehicles or medium-duty vehicles in a
given model year.
(c) The credit-deficit provisions 40 CFR 1036.745 apply to the
NMOG+NOX and evaporative emission standards for Tier 3 and
Tier 4 vehicles. Credit-deficit provisions are not affected by the
transition from Tier 3 to Tier 4 standards.
(d) The reporting and recordkeeping provisions of Sec. 86.1862
apply instead of those specified in 40 CFR 1036.730 and 1036.735.
(e) The provisions of 40 CFR 1036.625 do not apply.
Sec. Sec. 86.1865-12, 86.1866-12, 86.1867-12, and 86.1867-
31 [Removed]
0
43. Remove Sec. Sec. 86.1865-12, 86.1866-12, 86.1867-12, and 86.1867-
31.
0
44. Amend Sec. 86.1868-12 by:
0
a. Revising the introductory text and paragraph (c);
0
b. Removing and reserving paragraph (d); and
0
c. Revising paragraphs (g) introductory text and (g)(3) introductory
text.
The revisions read as follows:
Sec. 86.1868-12 CO2 credits for improving the efficiency of air
conditioning systems.
The regulation at 40 CFR 600.510 describes how manufacturers may
calculate fuel consumption improvement values based on improvements to
air conditioning efficiency. This section describes how to calculate
credits to determine the average fuel economy for comparing to the
Corporate Average Fuel Economy standard. The provisions of this section
do not apply for medium-duty vehicles. Credits shall be calculated
according to this section for each air conditioning system that the
manufacturer is using to generate credits. Manufacturers must validate
credits under this section based on testing as described in paragraph
(g) of this section. Starting in model year 2027, manufacturers may
generate credits under this section only for vehicles propelled by
internal combustion engines.
* * * * *
(c) The total efficiency credits generated by an air conditioning
system shall be calculated in megagrams separately for passenger
automobiles and light trucks according to the following formula:
[[Page 7766]]
Equation 1 to Paragraph (c)
[GRAPHIC] [TIFF OMITTED] TR18FE26.021
Where:
Credit = the air conditioning efficiency credit in grams per mile
determined in paragraph (b) of this section. Starting in model year
2027, multiply the credit value for PHEV by (1-UF), where UF = the
fleet utility factor established under 40 CFR 600.116-12(c)(1) or
(c)(10)(iii) (weighted 55 percent city, 45 percent highway.
Production = The total number of passenger automobiles or light
trucks, whichever is applicable, produced with the air conditioning
system to which to the efficiency credit value from paragraph (b) of
this section applies.
VLM = vehicle lifetime miles, which for passenger automobiles shall
be 195,264 and for light trucks shall be 225,865.
* * * * *
(g) For AC17 validation testing and reporting requirements,
manufacturers must validate air conditioning efficiency credits by
using the AC17 Test Procedure in 40 CFR 1066.845 as follows:
* * * * *
(3) For the first model year for which an air conditioning system
is expected to generate credits, the manufacturer must select for
testing the projected highest-selling vehicle configuration within each
combination of vehicle platform and air conditioning system (as those
terms are defined in Sec. 86.1803). The manufacturer must test at
least one unique air conditioning system within each vehicle platform
in a model year, unless all unique air conditioning systems within a
vehicle platform have been previously tested. A unique air conditioning
system design is a system with unique or substantially different
component designs or types and/or system control strategies (e.g.,
fixed-displacement vs. variable displacement compressors, orifice tube
vs. thermostatic expansion valve, single vs. dual evaporator, etc.). In
the first year of such testing, the tested vehicle configuration shall
be the highest production vehicle configuration within each platform.
In subsequent model years the manufacturer must test other unique air
conditioning systems within the vehicle platform, proceeding from the
highest production untested system until all unique air conditioning
systems within the platform have been tested, or until the vehicle
platform experiences a major redesign. Whenever a new unique air
conditioning system is tested, the highest production vehicle
configuration using that system shall be the vehicle selected for
testing. Credits may continue to be generated by the air conditioning
system installed in a vehicle platform provided that:
* * * * *
0
45. Amend Sec. 86.1869-12 by revising the introductory text and
paragraphs (a), (b)(1) introductory text, (b)(2) introductory text,
(b)(2)(v), (c) introductory text, and (e)(2)(i) to read as follows:
Sec. 86.1869-12 CO2 credits for off-cycle CO2 reducing technologies.
The regulation at 40 CFR 600.510 describes how manufacturers may
calculate fuel consumption improvement values based on vehicle
improvements that are not reflected in testing to demonstrate
compliance with exhaust emission standards. This section describes how
to calculate credits to determine the average fuel economy for
comparing to the Corporate Average Fuel Economy standard through model
year 2032. The provisions of this section do not apply for medium-duty
vehicles. Manufacturers may no longer generate credits under this
section starting in model year 2027 for vehicles deemed to have zero
tailpipe emissions and in model year 2033 for all other vehicles.
Manufacturers may no longer generate credits under paragraphs (c) and
(d) of this section for any type of vehicle starting in model year
2027.
(a) Manufacturers may generate credits for CO2-reducing
technologies where the CO2 reduction benefit of the
technology is not adequately captured on the Federal Test Procedure
and/or the Highway Fuel Economy Test such that the technology would not
be otherwise installed for purposes of meeting Corporate Average Fuel
Economy standards. These technologies must have a measurable,
demonstrable, and verifiable real-world CO2 reduction that
occurs outside the conditions of the Federal Test Procedure and the
Highway Fuel Economy Test. These optional credits are referred to as
``off-cycle'' credits. The technologies must not be integral or
inherent to the basic vehicle design, such as engine, transmission,
mass reduction, passive aerodynamic design, and tire technologies.
Technologies installed for non-off-cycle emissions related reasons are
also not eligible as they would be considered part of the baseline
vehicle design. The technology must not be inherent to the design of
occupant comfort and entertainment features except for technologies
related to reducing passenger air conditioning demand and improving air
conditioning system efficiency. Notwithstanding the provisions of this
paragraph (a), off-cycle menu technologies included in paragraph (b) of
this section remain eligible for credits. Off-cycle technologies used
to generate emission credits are considered emission-related components
subject to applicable requirements and must be demonstrated to be
effective for the full useful life of the vehicle. Unless the
manufacturer demonstrates that the technology is not subject to in-use
deterioration, the manufacturer must account for the deterioration in
their analysis. Durability evaluations of off-cycle technologies may
occur at any time throughout a model year, provided that the results
can be factored into the data provided in the model year report. Off-
cycle credits may not be approved for crash-avoidance technologies,
safety critical systems or systems affecting safety-critical functions,
or technologies designed for the purpose of reducing the frequency of
vehicle crashes. Off-cycle credits may not be earned for technologies
installed on a motor vehicle to attain compliance with any vehicle
safety standard or any regulation set forth in Title 49 of the Code of
Federal Regulations. The manufacturer must use one of the three options
specified in this section to establish off-cycle credits under this
section.
(b) * * *
(1) The manufacturer may generate off-cycle credits for certain
technologies as specified in this paragraph (b)(1). Technology
definitions are in paragraph (b)(4) of this section. Calculated credit
values shall be rounded to the nearest 0.1 grams/mile.
* * * * *
(2) The maximum allowable off-cycle credit for the combined
passenger automobile and light truck fleet
[[Page 7767]]
attributable to use of the default credit values in paragraph (b)(1) of
this section is specified in paragraph (b)(2)(v) of this section. If
the total of the off-cycle credit values from paragraph (b)(1) of this
section does not exceed the specified off-cycle credit cap for any
passenger automobile or light truck in a manufacturer's fleet, then the
total off-cycle credits may be calculated according to paragraph (f) of
this section. If the total of the off-cycle credit values from
paragraph (b)(1) of this section exceeds the specified off-cycle credit
cap for any passenger automobile or light truck in a manufacturer's
fleet, then the gram per mile decrease for the combined passenger
automobile and light truck fleet must be determined according to
paragraph (b)(2)(ii) of this section to determine whether the
applicable limitation has been exceeded.
* * * * *
(v) The manufacturer's combined passenger automobile and light
truck fleet average off-cycle credits attributable to use of the
default credit values in paragraph (b)(1) of this section may not
exceed the following specific values:
------------------------------------------------------------------------
Off-cycle
Model year credit cap
(g/mile)
------------------------------------------------------------------------
(A) 2023-2026.............................................. 15
(B) 2027-2030.............................................. 10
(C) 2031................................................... 8.0
(D) 2032................................................... 6.0
------------------------------------------------------------------------
* * * * *
(c) Technology demonstration using EPA 5-cycle methodology. To
demonstrate an off-cycle technology and to determine off-cycle credits
using the EPA 5-cycle methodology, the manufacturer shall determine the
off-cycle city/highway combined carbon-related exhaust emissions
benefit by using the EPA 5-cycle methodology described in 40 CFR part
600. This method may not be used for technologies that include elements
(e.g., driver-selectable systems) that require additional analyses,
data collection, projections, or modeling, or other assessments to
determine a national average benefit of the technology. Testing shall
be performed on a representative vehicle, selected using good
engineering judgment, for each model type for which the credit is being
demonstrated. The emission benefit of a technology is determined by
testing both with and without the off-cycle technology operating. If a
specific technology is not expected to change emissions on one of the
five test procedures, the manufacturer may submit an engineering
analysis to the EPA that demonstrates that the technology has no
effect. If EPA concurs with the analysis, then multiple tests are not
required using that test procedure; instead, only one of that test
procedure shall be required--either with or without the technology
installed and operating--and that single value will be used for all of
the 5-cycle weighting calculations. Multiple off-cycle technologies may
be demonstrated on a test vehicle. The manufacturer shall conduct the
following steps and submit all test data to the EPA.
* * * * *
(e) Review and approval process for off-cycle credits--(1) Initial
steps required. (i) A manufacturer requesting off-cycle credits under
the provisions of paragraph (c) of this section must conduct the
testing and/or simulation described in that paragraph.
(ii) A manufacturer requesting off-cycle credits under the
provisions of paragraph (d) of this section must develop a methodology
for demonstrating and determining the benefit of the off-cycle
technology, and carry out any necessary testing and analysis required
to support that methodology.
(iii) A manufacturer requesting off-cycle credits under paragraphs
(b), (c), or (d) of this section must conduct testing and/or prepare
engineering analyses that demonstrate the in-use durability of the
technology for the full useful life of the vehicle.
(2) Data and information requirements. The manufacturer seeking
off-cycle credits must submit an application for off-cycle credits
determined under paragraphs (c) and (d) of this section. The
application must contain the following:
(i) A detailed description of the off-cycle technology and how it
functions to improve fuel economy under conditions not represented on
the FTP and HFET.
(ii) A list of the vehicle model(s) which will be equipped with the
technology.
(iii) A detailed description of the test vehicles selected and an
engineering analysis that supports the selection of those vehicles for
testing.
(iv) All testing and/or simulation data required under paragraph
(c) or (d) of this section, as applicable, plus any other data the
manufacturer has considered in the analysis.
(v) For credits under paragraph (d) of this section, a complete
description of the methodology used to estimate the off-cycle benefit
of the technology and all supporting data, including vehicle testing
and in-use activity data.
(vi) An estimate of the off-cycle benefit by vehicle model and the
fleetwide benefit based on projected sales of vehicle models equipped
with the technology.
(vii) An engineering analysis and/or component durability testing
data or whole vehicle testing data demonstrating the in-use durability
of the off-cycle technology components.
(3) EPA review of the off-cycle credit application. Upon receipt of
an application from a manufacturer, EPA will do the following:
(i) Review the application for completeness and notify the
manufacturer within 30 days if additional information is required.
(ii) Review the data and information provided in the application to
determine if the application supports the level of credits estimated by
the manufacturer.
(iii) For credits under paragraph (d) of this section, EPA will
make the application available to the public for comment, as described
in paragraph (d)(2) of this section, within 60 days of receiving a
complete application. The public review period will be specified as 30
days, during which time the public may submit comments. Manufacturers
may submit a written rebuttal of comments for EPA consideration or may
revise their application in response to comments. A revised application
should be submitted after the end of the public review period, and EPA
will review the application as if it was a new application submitted
under this paragraph (e)(3).
(4) EPA decision. (i) For credits under paragraph (c) of this
section, EPA will notify the manufacturer of its decision within 60
days of receiving a complete application.
(ii) For credits under paragraph (d) of this section, EPA will
notify the manufacturer of its decision after reviewing and evaluating
the public comments. EPA will make the decision and rationale available
to the public.
(iii) EPA will notify the manufacturer in writing of its decision
to approve or deny the application, and will provide the reasons for
the decision. EPA will make the decision and rationale available to the
public.
* * * * *
Sec. 86.1870-12 [Removed]
0
46. Remove Sec. 86.1870-12.
[[Page 7768]]
PART 600--FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF
MOTOR VEHICLES
0
47. The authority citation for part 600 continues to read as follows:
Authority: 49 U.S.C. 32901--23919Q, Pub. L. 109-58.
0
48. Amend Sec. 600.001 by revising paragraphs (a) and (c) to read as
follows:
Sec. 600.001 General applicability.
(a) The provisions of this part apply to 2008 and later model year
automobiles that are not medium duty passenger vehicles
(MDPVFE), and to 2011 and later model year automobiles
including MDPVFE. The test procedures in subpart B of this
part also describe how manufacturers can test larger vehicles to meet
fuel consumption standards under 49 CFR part 535.
* * * * *
(c) Unless stated otherwise, references to fuel economy or fuel
economy data in this part shall also be interpreted to mean the related
exhaust emissions of CO2, HC, and CO, and where applicable
for alternative fuel vehicles, CH3OH,
C2H5OH, C2H4O, HCHO, NMHC
and CH4.
* * * * *
0
49. Amend Sec. 600.002 by:
0
a. Revising the definitions of ``Carbon-related exhaust emissions
(CREE)'' and ``Engine code'';
0
b. Removing the definition of ``Footprint''; and
0
c. Revising the definitions of ``Medium-duty passenger vehicle
(MDPVFE)'', ``Subconfiguration'', and ``Vehicle
configuration''.
The revisions read as follows:
Sec. 600.002 Definitions.
* * * * *
Carbon-related exhaust emissions (CREE) means the summation of the
carbon-containing constituents of the exhaust emissions, with each
constituent adjusted by a coefficient representing the carbon weight
fraction of each constituent relative to the CO2 carbon
weight fraction, as specified in Sec. 600.113.
* * * * *
Engine code means one of the following:
(1) For LDV, LDT, and MDPVFE, engine code means a unique
combination, within a test group (as defined in Sec. 86.1803 of this
chapter), of displacement, fuel injection (or carburetion or other fuel
delivery system), calibration, distributor calibration, choke
calibration, auxiliary emission control devices, and other engine and
emission control system components specified by the Administrator. For
electric vehicles, engine code means a unique combination of
manufacturer, electric traction motor, motor configuration, motor
controller, and energy storage device.
(2) For MDV, engine code means the combination of both ``engine
code'' and ``basic engine'' as defined for light-duty vehicles in this
section.
* * * * *
Medium-duty passenger vehicle (MDPVFE) means any motor
vehicle rated at more than 8,500 pounds GVWR and less than 10,000
pounds GVWR that is designed primarily to transport passengers, but
does not include a vehicle that--
(1) Is an ``incomplete truck,'' meaning any truck which does not
have the primary load carrying device or container attached when it is
first sold as a vehicle; or
(2) Has a seating capacity of more than 12 persons; or
(3) Is designed for more than 9 persons in seating rearward of the
driver's seat; or
(4) Is equipped with an open cargo area (for example, a pick-up
truck box or bed) of 72.0 inches in interior length or more. A covered
box not readily accessible from the passenger compartment will be
considered an open cargo area for purposes of this definition. (See
paragraph (1) of the definition of medium-duty passenger vehicle at 40
CFR 86.1803-01).
* * * * *
Subconfiguration means one of the following:
(1) For LDV, LDT, and MDPVFE, subconfiguration means a
unique combination within a vehicle configuration of equivalent test
weight, road-load horsepower, and any other operational characteristics
or parameters which the Administrator determines may significantly
affect fuel economy or CO2 emissions within a vehicle
configuration.
(2) For MDV, subconfiguration means a unique combination within a
vehicle configuration of equivalent test weight, road-load horsepower,
and any other operational characteristics or parameters that may
significantly affect CO2 emissions within a vehicle
configuration. Note that equivalent test weight is based on a vehicle's
Adjusted Loaded Vehicle Weight (rounded to the nearest 500-pound
increment for values above 14,000 pounds); see 40 CFR 1066.805.
* * * * *
Vehicle configuration means one of the following:
(1) For LDV, LDT, and MDPVFE, vehicle configuration
means a unique combination of basic engine, engine code, inertia weight
class, transmission configuration, and axle ratio within a base level.
(2) For MDV, vehicle configuration means a subclassification within
a test group based on a unique combination of basic engine, engine
code, transmission type and gear ratios, final drive ratio, and other
parameters we designate.
* * * * *
0
50. Amend Sec. 600.006 by revising paragraphs (c)(5), (e), and
(g)(3)(ii) to read as follows:
Sec. 600.006 Data and information requirements for fuel economy data
vehicles.
* * * * *
(c) * * *
(5) Starting with the 2012 model year, the data submitted according
to paragraphs (c)(1) through (4) of this section shall include total
HC, CO, CO2, and, where applicable for alternative fuel
vehicles, CH3OH, C2H5OH,
C2H4O, HCHO, NMHC and CH4.
* * * * *
(e) In lieu of submitting actual data from a test vehicle, a
manufacturer may provide fuel economy and CO2 emission
values derived from a previously tested vehicle, where the fuel economy
and CO2 emissions are expected to be equivalent (or less
fuel-efficient and with higher CO2 emissions). Additionally,
in lieu of submitting actual data from a test vehicle, a manufacturer
may provide fuel economy and CO2 emission values derived
from an analytical expression, e.g., regression analysis. In order for
fuel economy and CO2 emission values derived from analytical
methods to be accepted, the expression (form and coefficients) must
have been approved by the Administrator.
* * * * *
(g) * * *
(3) * * *
(ii)(A) The manufacturer shall adjust all CO2 test data
generated by vehicles with engine-drive system combinations with more
than 6,200 miles by using the following equation:
ADJ4,000mi = TEST[0.979 + 5.25 [middot] 10-6
[middot] (mi)]
Where:
ADJ4,000mi = CO2 emission data adjusted to
4,000-mile test point.
TEST = Tested emissions value of CO2 in grams per mile.
mi = System miles accumulated at the start of the test rounded to
the nearest whole mile.
[[Page 7769]]
(B) Emissions test values and results used and determined in the
calculations in this paragraph (g)(3)(ii) shall be rounded in
accordance with Sec. 86.1837 of this chapter as applicable. Round
results to the nearest gram per mile.
* * * * *
0
51. Amend Sec. 600.007 by revising paragraphs (b)(5) and (6), (c), and
(f) introductory text to read as follows:
Sec. 600.007 Vehicle acceptability.
* * * * *
(b) * * *
(5) The calibration information submitted under Sec. 600.006(b)
must be representative of the vehicle configuration for which the fuel
economy and CO2 emission data were submitted.
(6) Any vehicle tested for fuel economy or CO2 emissions
must be representative of a vehicle which the manufacturer intends to
produce under the provisions of a certificate of conformity.
* * * * *
(c) If, based on review of the information submitted under Sec.
600.006(b), the Administrator determines that a fuel economy data
vehicle meets the requirements of this section, the fuel economy data
vehicle will be judged to be acceptable and fuel economy data from that
fuel economy data vehicle will be reviewed pursuant to Sec. 600.008.
* * * * *
(f) All vehicles used to generate fuel economy data, and for which
emission standards apply, must be covered by a certificate of
conformity under part 86 of this chapter before:
* * * * *
0
52. Amend Sec. 600.008 by revising the section heading and paragraph
(a)(1)(ii) to read as follows:
Sec. 600.008 Review of fuel economy and CO2 emission data,
testing by the Administrator.
(a) * * *
(1) * * *
(ii) The evaluations, testing, and test data described in this
section pertaining to fuel economy shall also be performed for
CO2 emissions, except that CO2 emissions shall be
arithmetically averaged instead of harmonically averaged, and in cases
where the manufacturer selects the lowest of several fuel economy
results to represent the vehicle, the manufacturer shall select the
CO2 emission value from the test results associated with the
lowest selected fuel economy results.
* * * * *
0
53. Amend Sec. 600.010 by revising paragraphs (c)(1)(ii) and (d) to
read as follows:
Sec. 600.010 Vehicle test requirements and minimum data requirements.
* * * * *
(c) * * *
(1) * * *
(ii)(A) FTP and HFET data from the highest projected model year
sales subconfiguration within the highest projected model year sales
vehicle configuration for each base level, and
(B) If required under Sec. 600.115, for 2011 and later model year
vehicles, US06, SC03 and cold temperature FTP data from the highest
projected model year sales subconfiguration within the highest
projected model year sales vehicle configuration for each base level.
Manufacturers may optionally generate this data for any 2008 through
2010 model years and 2011 and later model year vehicles, if not
otherwise required.
* * * * *
(d) Minimum data requirements for the manufacturer's average fuel
economy. For the purpose of calculating the manufacturer's average fuel
economy under Sec. 600.510, the manufacturer shall submit FTP (city)
and HFET (highway) test data representing at least 90 percent of the
manufacturer's actual model year production, by vehicle configuration,
for each category identified for calculation under Sec. 600.510-
12(a)(1).
Subpart B--Fuel Economy and Exhaust Emission Test Procedures
0
54. Revise the heading of subpart B as set forth above.
0
55. Amend Sec. 600.101 by:
0
a. Revising paragraph (a)(2); and
0
b. Removing and reserving paragraph (b)(2).
The revision reads as follows:
Sec. 600.101 Testing overview.
* * * * *
(a) * * *
(2) Calculate fuel economy values for vehicle subconfigurations,
configurations, base levels, and model types as described in Sec. Sec.
600.206 and 600.208. Calculate fleet average values for fuel economy as
described in Sec. 600.510. Note that Sec. 600.510(c) describes how to
use CREE to determine fuel consumption improvement values for specific
cases.
* * * * *
0
56. Amend Sec. 600.111-08 by revising paragraph (h) to read as
follows:
Sec. 600.111-08 Test procedures.
* * * * *
(h) Special test procedures. We may allow or require you to use
procedures other than those specified in this section as described in
40 CFR 1066.10(c). For example, special test procedures may be used for
advanced technology vehicles, including, but not limited to fuel cell
vehicles, hybrid electric vehicles using hydraulic energy storage, and
vehicles equipped with hydrogen internal combustion engines.
Additionally, we may conduct fuel economy and exhaust emission testing
using the special test procedures approved for a specific vehicle.
0
57. Amend Sec. 600.113-12 by:
0
a. Revising the section heading, introductory text, and paragraph (g);
0
b. Removing and reserving paragraphs (h)(2), (i)(2), (j)(2), (k)(2),
(l)(2), (m)(2);
0
c. Revising paragraph (n);
0
d. Removing and reserving paragraph (o)(2); and
0
e. Revising paragraph (p).
The revisions read as follows:
Sec. 600.113-12 Fuel economy and CO2 emission calculations for FTP,
HFET, US06, SC03 and cold temperature FTP tests.
The Administrator will use the calculation procedure set forth in
this section for all official EPA testing of vehicles fueled with
gasoline, diesel, alcohol-based or natural gas fuel. The calculations
of the weighted fuel economy values require input of the weighted
grams/mile values for total hydrocarbons (HC), carbon monoxide (CO),
and carbon dioxide (CO2); and, additionally for methanol-
fueled automobiles, methanol (CH3OH) and formaldehyde
(HCHO); and, additionally for ethanol-fueled automobiles, methanol
(CH3OH), ethanol (C2H5OH),
acetaldehyde (C2H4O), and formaldehyde (HCHO);
and additionally for natural gas-fueled vehicles, non-methane
hydrocarbons (NMHC) and methane (CH4). Emissions shall be
determined for the FTP, HFET, US06, SC03, and cold temperature FTP
tests. Additionally, the specific gravity, carbon weight fraction and
net heating value of the test fuel must be determined. The FTP, HFET,
US06, SC03, and cold temperature FTP fuel economy values shall be
calculated as specified in this section. An example fuel economy
calculation appears in appendix II to this part.
* * * * *
(g) Calculate separate FTP, highway, US06, SC03 and Cold
temperature FTP fuel economy values from the grams/mile values for
total HC, CO, CO2 and, where applicable, CH3OH,
C2H5OH, C2H4O, HCHO, NMHC,
N2O, and CH4, and the test fuel's specific
gravity, carbon weight fraction, net heating
[[Page 7770]]
value, and additionally for natural gas, the test fuel's composition.
(1) Emission values for fuel economy calculations. The emission
values (obtained per paragraph (a) through (e) of this section, as
applicable) used in the calculations of fuel economy in this section
shall be rounded in accordance with Sec. 86.1837 of this chapter. The
CO2 values (obtained per this section, as applicable) used
in each calculation of fuel economy in this section shall be rounded to
the nearest gram/mile.
(2) [Reserved]
(3) The specific gravity and the carbon mass fraction (obtained per
paragraph (f) of this section) shall be recorded using three places to
the right of the decimal point. Net heat of combustion shall be
recorded using three places to the right of the decimal point if
expressed in MJ/kg, or the nearest whole number if expressed in Btu/lb.
* * * * *
(n) Manufacturers may use a value of 0 grams CO2 per
mile to represent the emissions of electric vehicles and the electric
operation of plug-in hybrid electric vehicles derived from electricity
generated from sources that are not onboard the vehicle.
* * * * *
(p) Equations for fuels other than those specified in this section
may be used with advance EPA approval. Alternate calculation methods
for fuel economy may be used in lieu of the methods described in this
section if shown to yield equivalent or superior results and if
approved in advance by the Administrator.
0
58. Amend Sec. 600.114-12 by revising the section heading and
introductory text to read as follows:
Sec. 600.114-12 Vehicle-specific 5-cycle fuel economy CO2 emission
calculations.
Paragraphs (a) through (f) of this section apply to data used for
fuel economy labeling under subpart D of this part. Paragraphs (d)
through (f) of this section are used to calculate 5-cycle carbon-
related exhaust emission values for the purpose of determining optional
credits for CO2-reducing technologies under Sec. 86.1869-12
of this chapter and to calculate 5-cycle CO2 values for the
purpose of fuel economy labeling under subpart D of this part.
* * * * *
0
59. Amend Sec. 600.116-12 by revising paragraphs (a)(11)(iii)(E), (c)
introductory text, (c)(1), (c)(2), (c)(5), and (c)(6)(iii) to read as
follows:
Sec. 600.116-12 Special procedures related to electric vehicles and
hybrid electric vehicles.
(a) * * *
(11) * * *
(iii) * * *
(E) A description of each test group and vehicle configuration that
will use the 5-cycle adjustment factor, including the battery capacity
of the vehicle used to generate the 5-cycle adjustment factor and the
battery capacity of all the vehicle configurations to which it will be
applied.
* * * * *
(c) Determine performance values for hybrid electric vehicles that
have plug-in capability as specified in Sec. Sec. 600.210 and 600.311
using the procedures of SAE J1711 (incorporated by reference, see Sec.
600.011), with the following clarifications and modifications:
(1) Calculate fuel economy values representing combined operation
during charge-depleting and charge-sustaining operation using the
following utility factors, except as otherwise specified in this
paragraph (c):
Table 1 to Paragraph (c)(1)--Fleet Utility Factors for Urban ``City''
Driving
------------------------------------------------------------------------
Schedule range for UDDS phases,
miles Cumulative UF Sequential UF
------------------------------------------------------------------------
3.59............................ 0.125 0.125
7.45............................ 0.243 0.117
11.04........................... 0.338 0.095
14.90........................... 0.426 0.088
18.49........................... 0.497 0.071
22.35........................... 0.563 0.066
25.94........................... 0.616 0.053
29.80........................... 0.666 0.049
33.39........................... 0.705 0.040
37.25........................... 0.742 0.037
40.84........................... 0.772 0.030
44.70........................... 0.800 0.028
48.29........................... 0.822 0.022
52.15........................... 0.843 0.021
55.74........................... 0.859 0.017
59.60........................... 0.875 0.016
63.19........................... 0.888 0.013
67.05........................... 0.900 0.012
70.64........................... 0.909 0.010
------------------------------------------------------------------------
Table 2 to Paragraph (c)(1)--Fleet Utility Factors for Highway Driving
------------------------------------------------------------------------
Schedule range for HFET, miles Cumulative UF Sequential UF
------------------------------------------------------------------------
10.3............................ 0.123 0.123
20.6............................ 0.240 0.117
30.9............................ 0.345 0.105
41.2............................ 0.437 0.092
51.5............................ 0.516 0.079
61.8............................ 0.583 0.067
72.1............................ 0.639 0.056
------------------------------------------------------------------------
[[Page 7771]]
(2) Determine fuel economy values to demonstrate compliance with
CAFE standards as follows:
(i) For vehicles that are not dual fueled automobiles, determine
fuel economy using the utility factors specified in paragraph (c)(1) of
this section. Do not use the petroleum-equivalence factors described in
10 CFR 474.3.
(ii) Except as described in paragraph (c)(2)(iii) of this section,
determine fuel economy for dual fueled automobiles from the following
equation, separately for city and highway driving:
Equation 2 to Paragraph (c)(2)(ii)
[GRAPHIC] [TIFF OMITTED] TR18FE26.022
Where:
MPGgas = The miles per gallon measured while operating on
gasoline during charge-sustaining operation as determined using the
procedures of SAE J1711.
MPGeelec = The miles per gallon equivalent measured while
operating on electricity. Calculate this value by dividing the
equivalent all-electric range determined from the equation in Sec.
86.1866-12(b)(2)(ii) by the corresponding measured Watt-hours of
energy consumed; apply the appropriate petroleum-equivalence factor
from 10 CFR 474.3 to convert Watt-hours to gallons equivalent. Note
that if vehicles use no gasoline during charge-depleting operation,
MPGeelec is the same as the charge-depleting fuel economy
specified in SAE J1711.
(iii) For 2016 and later model year dual fueled automobiles, you
may determine fuel economy based on the following equation, separately
for city and highway driving:
Equation 3 to Paragraph (c)(2)(iii)
[GRAPHIC] [TIFF OMITTED] TR18FE26.023
Where:
UF = The appropriate utility factor for city or highway driving
specified in paragraph (c)(1) of this section.
* * * * *
(5) Instead of the utility factors specified in paragraphs (c)(1)
through (3) of this section, calculate utility factors using the
following equation for vehicles whose maximum speed is less than the
maximum speed specified in the driving schedule, where the vehicle's
maximum speed is determined, to the nearest 0.1 mph, from observing the
highest speed over the first duty cycle (FTP, HFET, etc.):
Equation 4 to Paragraph (c)(5)
[GRAPHIC] [TIFF OMITTED] TR18FE26.024
Where:
UFi = the utility factor for phase i. Let UF0
= 0.
j = a counter to identify the appropriate term in the summation
(with terms numbered consecutively).
k = the number of terms in the equation (see Table 5 of this
section).
di = the distance driven in phase i.
ND = the normalized distance. Use ND = 399 for all types of driving,
and for both CAFE fleet values and multi-day individual values for
labeling.
Cj = the coefficient for term j from the following table:
Table 5 to Paragraph (c)(5)--City/Highway Specific Utility Factor Coefficients
----------------------------------------------------------------------------------------------------------------
Fleet values for CAFE Multi-day individual
-------------------------------- values for labeling
j ------------------------
City Highway City or highway
----------------------------------------------------------------------------------------------------------------
1...................................................... 14.86 4.8 13.1
2...................................................... 2.965 13 -18.7
3...................................................... -84.05 -65 5.22
4...................................................... 153.7 120 8.15
5...................................................... -43.59 -100.00 3.53
6...................................................... -96.94 31.00 -1.34
7...................................................... 14.47 .............. -4.01
8...................................................... 91.70 .............. -3.90
9...................................................... -46.36 .............. -1.15
10..................................................... .............. .............. 3.88
----------------------------------------------------------------------------------------------------------------
n = the number of test phases (or bag measurements) before the
vehicle reaches the end-of-test criterion.
(6) * * *
(iii) For charge-sustaining tests, we may approve alternate Net
Energy Change/Fuel Ratio tolerances as specified in Appendix C of SAE
J1711 to correct final fuel economy values and CO2
emissions. For charge-sustaining tests, do not use alternate Net Energy
Change/Fuel Ratio tolerances to correct emissions of criteria
pollutants. Additionally, if we approve an alternate
[[Page 7772]]
End-of-Test criterion or Net Energy Change/Fuel Ratio tolerances for a
specific vehicle, we may use the alternate criterion or tolerances for
any testing we conduct on that vehicle.
* * * * *
0
60. Amend Sec. 600.117 by:
0
a. Revising paragraph (a)(1);
0
b. Removing and reserving paragraph (a)(5); and
0
c. Revising paragraphs (a)(6) and (b) to read as follows:
The revisions read as follows:
Sec. 600.117 Interim provisions.
(a) * * *
(1) Except as specified in paragraphs (a)(5) and (6) of this
section, manufacturers must determine fuel economy values using E0
gasoline test fuel as specified in 40 CFR 86.113-04(a)(1), regardless
of any testing with E10 test fuel specified in 40 CFR 1065.710(b) under
paragraph (a)(2) of this section.
* * * * *
(6) Manufacturers may alternatively determine fuel economy values
using E10 gasoline test fuel as specified in 40 CFR 1065.710(b).
Calculate fuel economy using the equation specified in Sec. 600.113-
12(o)(1) based on measured CO2 results without adjusting to
account for fuel effects.
* * * * *
(b) For model years 2027 through 2029, manufacturers may determine
fuel economy values using data with E0 test fuel from testing for
earlier model years, subject to the carryover provisions of 40 CFR
86.1839 and Sec. 600.006. Calculate fuel economy using the equation
specified in Sec. 600.113-12(h)(1) based on measured CO2
results without adjusting to account for fuel effects.
* * * * *
0
61. Amend Sec. 600.206-12 by revising paragraphs (a) introductory
text, (a)(4) introductory text, (b), and (c) to read as follows:
Sec. 600.206-12 Calculation and use of FTP-based and HFET-based fuel
economy, CO2 emissions, and carbon-related exhaust emission values for
vehicle configurations.
(a) Fuel economy, CO2 emissions, and carbon-related
exhaust emissions values determined for each vehicle under Sec.
600.113-12(a) and (b) and as approved in Sec. 600.008(c), are used to
determine FTP-based city, HFET-based highway, and combined FTP/Highway-
based fuel economy, CO2 emissions, and carbon-related
exhaust emission values for each vehicle configuration for which data
are available. Note that fuel economy for some alternative fuel
vehicles may mean miles per gasoline gallon equivalent and/or miles per
unit of fuel consumed. For example, electric vehicles will determine
miles per kilowatt-hour in addition to miles per gasoline gallon
equivalent, and fuel cell vehicles will determine miles per kilogram of
hydrogen.
* * * * *
(4) For alcohol dual fuel automobiles and natural gas dual fuel
automobiles the procedures of paragraphs (a)(1) or (2) of this section,
as applicable, shall be used to calculate two separate sets of FTP-
based city, HFET-based highway, and combined values for fuel economy,
CO2 emissions, and carbon-related exhaust emissions for each
vehicle configuration.
* * * * *
(b) If only one equivalent petroleum-based fuel economy value
exists for an electric vehicle configuration, that value, rounded to
the nearest tenth of a mile per gallon, will comprise the petroleum-
based fuel economy for that vehicle configuration.
(c) If more than one equivalent petroleum-based fuel economy value
exists for an electric vehicle configuration, all values for that
vehicle configuration are harmonically averaged and rounded to the
nearest 0.0001 mile per gallon for that vehicle configuration.
0
62. Amend Sec. 600.207-12 by revising paragraphs (a)(1), (a)(4)
introductory text, (b), and (c) to read as follows:
Sec. 600.207-12 Calculation and use of vehicle-specific 5-cycle-based
fuel economy and CO2 emission values for vehicle configurations.
(a) * * *
(1) If only one set of 5-cycle city and highway fuel economy and
CO2 emission values is accepted for a vehicle configuration,
these values, where fuel economy is rounded to the nearest 0.0001 of a
mile per gallon and the CO2 emission value in grams per mile
is rounded to the nearest tenth of a gram per mile, comprise the city
and highway fuel economy and CO2 emission values for that
vehicle configuration. Note that the appropriate vehicle-specific
CO2 values for fuel economy labels based on 5-cycle testing
with E10 test fuel are adjusted as described in Sec. 600.114-12.
* * * * *
(4) For alcohol dual fuel automobiles and natural gas dual fuel
automobiles, the procedures of paragraphs (a)(1) and (2) of this
section shall be used to calculate two separate sets of 5-cycle city
and highway fuel economy and CO2 emission values for each
vehicle configuration.
* * * * *
(b) If only one equivalent petroleum-based fuel economy value
exists for an electric vehicle configuration, that value, rounded to
the nearest tenth of a mile per gallon, will comprise the petroleum-
based 5-cycle fuel economy for that vehicle configuration.
(c) If more than one equivalent petroleum-based 5-cycle fuel
economy value exists for an electric vehicle configuration, all values
for that vehicle configuration are harmonically averaged and rounded to
the nearest 0.0001 mile per gallon for that vehicle configuration.
0
63. Amend Sec. 600.210-12 by revising paragraph (b) to read as
follows:
Sec. 600.210-12 Calculation of fuel economy and CO2 emission values
for labeling.
* * * * *
(b) Specific labels. Except as specified in paragraphs (d) and (e)
of this section, fuel economy and CO2 emissions for specific
labels may be determined by one of two methods. The first is based on
vehicle-specific vehicle configuration 5-cycle data as determined in
Sec. 600.207. This method is available for all vehicles and is
required for vehicles that do not qualify for the second method as
described in Sec. 600.115 (other than electric vehicles). The second
method, the derived 5-cycle method, determines fuel economy and
CO2 emissions values from the FTP and HFET tests using
equations that are derived from vehicle-specific 5-cycle vehicle
configuration data, as determined in paragraph (b)(2) of this section.
Manufacturers may voluntarily lower fuel economy values and raise
CO2 values if they determine that the label values from
either method are not representative of the fuel economy or
CO2 emissions for that model type.
(1) Vehicle-specific 5-cycle labels. The city and highway vehicle
configuration fuel economy determined in Sec. 600.207, rounded to the
nearest mpg, and the city and highway vehicle configuration
CO2 emissions determined in Sec. 600.207, rounded to the
nearest gram per mile, comprise the fuel economy and CO2
emission values for specific fuel economy labels, or, alternatively;
(2) Derived 5-cycle labels. Specific city and highway label values
from derived 5-cycle are determined according to the following method:
(i)(A) Determine the derived five-cycle city fuel economy of the
vehicle configuration using the equation below and coefficients
determined by the Administrator:
[[Page 7773]]
[GRAPHIC] [TIFF OMITTED] TR18FE26.025
Where:
City Intercept = Intercept determined by the Administrator based on
historic vehicle-specific 5-cycle city fuel economy data.
City Slope = Slope determined by the Administrator based on historic
vehicle-specific 5-cycle city fuel economy data.
Config FTP FE = the vehicle configuration FTP-based city fuel
economy determined under Sec. 600.206, rounded to the nearest
0.0001 mpg.
(B) Determine the derived five-cycle city CO2 emissions
of the vehicle configuration using the equation below and coefficients
determined by the Administrator:
Derived 5-cycle City CO2 = City Intercept + City Slope
[middot] Config FTP CO2
Where:
City Intercept = Intercept determined by the Administrator based on
historic vehicle-specific 5-cycle city fuel economy data.
City Slope = Slope determined by the Administrator based on historic
vehicle-specific 5-cycle city fuel economy data.
Config FTP CO2 = the vehicle configuration FTP-based city
CO2 emissions determined under Sec. 600.206, rounded to
the nearest 0.1 grams per mile. Note that the appropriate Config FTP
CO2 input values for fuel economy labels based on testing
with E10 test fuel are adjusted as referenced in Sec. 600.206-
12(a)(2)(iii).
(ii)(A) Determine the derived five-cycle highway fuel economy of
the vehicle configuration using the equation below and coefficients
determined by the Administrator:
[GRAPHIC] [TIFF OMITTED] TR18FE26.026
Where:
Highway Intercept = Intercept determined by the Administrator based
on historic vehicle-specific 5-cycle highway fuel economy data.
Highway Slope = Slope determined by the Administrator based on
historic vehicle-specific 5-cycle highway fuel economy data.
Config HFET FE = the vehicle configuration highway fuel economy
determined under Sec. 600.206, rounded to the nearest tenth.
(B) Determine the derived five-cycle highway CO2
emissions of the vehicle configuration using the equation below and
coefficients determined by the Administrator:
Derived 5-cycle city Highway CO2 = Highway Intercept + Highway Slope
[middot] Config HFET CO2
Where:
Highway Intercept = Intercept determined by the Administrator based
on historic vehicle-specific 5-cycle highway fuel economy data.
Highway Slope = Slope determined by the Administrator based on
historic vehicle-specific 5-cycle highway fuel economy data.
Config HFET CO2 = the vehicle configuration highway fuel
economy determined under Sec. 600.206, rounded to the nearest
tenth. Note that the appropriate Config HFET CO2 input
values for fuel economy labels based on testing with E10 test fuel
are adjusted as referenced in Sec. 600.206-12(a)(2)(iii).
(iii) The slopes and intercepts of paragraph (a)(2)(iii) of this
section apply.
(3) Specific alternative fuel economy and CO2emissions
label values for dual fuel vehicles. (i) Determine an alternative fuel
label value for dual fuel vehicles, rounded to the nearest whole
number, as follows:
(A) Specific city and highway fuel economy label values for dual
fuel alcohol-based and natural gas vehicles when using the alternative
fuel are separately determined by the following calculation:
[GRAPHIC] [TIFF OMITTED] TR18FE26.027
Where:
FEalt = The unrounded FTP-based vehicle configuration
city or HFET-based vehicle configuration highway fuel economy from
the alternative fuel, as determined in Sec. 600.206.
5cycle FEgas = The unrounded vehicle-specific or derived
5-cycle vehicle configuration city or highway fuel economy as
determined in paragraph (b)(1) or (2) of this section.
FEgas = The unrounded FTP-based city or HFET-based
vehicle configuration highway fuel economy from gasoline, as
determined in Sec. 600.206.
(B) Specific city and highway CO2 emission label values
for dual fuel alcohol-based and natural gas vehicles when using the
alternative fuel are separately determined by the following
calculation:
[GRAPHIC] [TIFF OMITTED] TR18FE26.028
[[Page 7774]]
Where:
CO2alt = The unrounded FTP-based vehicle configuration
city or HFET-based vehicle configuration highway CO2
emissions value from the alternative fuel, as determined in Sec.
600.206.
5cycle CO2gas = The unrounded vehicle-specific or derived
5-cycle vehicle configuration city or highway CO2
emissions value as determined in paragraph (b)(1) or (b)(2) of this
section.
CO2gas = The unrounded FTP-based city or HFET-based
vehicle configuration highway CO2 emissions value from
gasoline, as determined in Sec. 600.206.
(ii) Optionally, if complete 5-cycle testing has been performed
using the alternative fuel, the manufacturer may choose to use the
alternative fuel label city or highway fuel economy and CO2
emission values determined in Sec. 600.207-12(a)(4)(ii), rounded to
the nearest whole number.
(4) Specific alternative fuel economy and CO2 emissions
label values for electric vehicles. Determine FTP-based city and HFET-
based highway fuel economy label values for electric vehicles as
described in Sec. 600.116. Determine these values by running the
appropriate repeat test cycles. Convert W-hour/mile results to miles
per kW-hr and miles per gasoline gallon equivalent. CO2
label information is based on tailpipe emissions only, so
CO2 emissions from electric vehicles are assumed to be zero.
(5) Specific alternate fuel economy and CO2 emissions
label values for fuel cell vehicles. Determine FTP-based city and HFET-
based highway fuel economy label values for fuel cell vehicles using
procedures specified by the Administrator. Convert kilograms of
hydrogen/mile results to miles per kilogram of hydrogen and miles per
gasoline gallon equivalent. CO2 label information is based
on tailpipe emissions only, so CO2 emissions from fuel cell
vehicles are assumed to be zero.
* * * * *
Subpart F--Procedures for Determining Manufacturer's Average Fuel
Economy
0
64. Revise the heading of subpart F as set forth above.
0
65. Amend Sec. 600.507-12 by revising paragraphs (a) introductory
text, (b), and (d) to read as follows:
Sec. 600.507-12 Running change data requirements.
(a) Except as specified in paragraph (d) of this section, the
manufacturer shall submit additional running change fuel economy data
as specified in paragraph (b) of this section for any running change
approved or implemented under Sec. 86.1842 of this chapter, which:
* * * * *
(b)(1) The additional running change fuel economy data requirement
in paragraph (a) of this section will be determined based on the sales
of the vehicle configurations in the created or affected base level(s)
as updated at the time of running change approval.
(2) Within each newly created base level as specified in paragraph
(a)(1) of this section, the manufacturer shall submit data from the
highest projected total model year sales subconfiguration within the
highest projected total model year sales vehicle configuration in the
base level.
(3) Within each base level affected by a running change as
specified in paragraph (a)(2) of this section, fuel economy data shall
be submitted for the vehicle configuration created or affected by the
running change which has the highest total model year projected sales.
The test vehicle shall be of the subconfiguration created by the
running change which has the highest projected total model year sales
within the applicable vehicle configuration.
* * * * *
(d) For those model types created under Sec. 600.208-12(a)(2), the
manufacturer shall submit fuel economy data for each subconfiguration
added by a running change.
0
66. Revise Sec. 600.509-12 to read as follows:
Sec. 600.509-12 Voluntary submission of additional data.
(a) The manufacturer may optionally submit data in addition to the
data required by the Administrator.
(b) Additional fuel economy data may be submitted by the
manufacturer for any vehicle configuration which is to be tested as
required in Sec. 600.507 or for which fuel economy data were
previously submitted under paragraph (c) of this section.
(c) Within a base level, additional fuel economy data may be
submitted by the manufacturer for any vehicle configuration which is
not required to be tested by Sec. 600.507.
0
67. Amend Sec. 600.510-12 by:
0
a. Revising the section heading;
0
b. Removing and reserving paragraph (a)(2);
0
c. Revising paragraphs (b) and (g)(1) introductory text; and
0
d. Removing paragraphs (i), (j), and (k).
The revisions read as follows:
Sec. 600.510-12 Calculation of average fuel economy.
* * * * *
(b) For the purpose of calculating average fuel economy under
paragraph (c) of this section:
(1) All fuel economy data submitted in accordance with Sec.
600.006(e) or Sec. 600.512(c) shall be used.
(2) The combined city/highway fuel economy values will be
calculated for each model type in accordance with Sec. 600.208, with
the following exceptions:
(i) Separate fuel economy values will be calculated for model types
and base levels associated with car lines for each category of
passenger automobiles and light trucks as determined by the Secretary
of Transportation pursuant to paragraph (a)(1) of this section.
(ii) Total model year production data, as required by this subpart,
will be used instead of sales projections.
(iii) The fuel economy value will be rounded to the nearest 0.1
mpg; and
(iv) At the manufacturer's option, those vehicle configurations
that are self-compensating to altitude changes may be separated by
sales into high-altitude sales categories and low-altitude sales
categories. These separate sales categories may then be treated (only
for the purpose of this section) as separate vehicle configurations in
accordance with the procedure of Sec. 600.208-12(a)(4)(ii).
(3) The fuel economy values for each vehicle configuration are the
combined fuel economy calculated according to Sec. 600.206-12(a)(3),
with the following exceptions:
(i) Separate fuel economy values will be calculated for vehicle
configurations associated with car lines for each category of passenger
automobiles and light trucks as determined by the Secretary of
Transportation pursuant to paragraph (a)(1) of this section; and
(ii) Total model year production data, as required by this subpart
will be used instead of sales projections.
* * * * *
(g)(1) Dual fuel automobiles must provide equal or greater energy
efficiency while operating on the alternative fuel as while operating
on gasoline or diesel fuel to obtain the CAFE credit determined in
paragraphs (c)(2)(iv) and (v) of this section. The following equation
must hold true:
* * * * *
0
68. Amend Sec. 600.512-12 by:
0
a. Revising paragraph (a) introductory text;
0
b. Removing and reserving paragraphs (a)(2), (c)(1)(ii), and
(c)(2)(ii);
0
c. Revising paragraph (c)(3);
[[Page 7775]]
0
d. Removing and reserving paragraphs (c)(4)(ii) and (c)(5)(ii); and
0
e. Removing paragraph (c)(11).
The revisions read as follows:
Sec. 600.512-12 Model year report.
(a) For each model year, the manufacturer shall submit to the
Administrator a report, known as the model year report, containing all
information necessary for the calculation of the manufacturer's average
fuel economy.
* * * * *
(c) * * *
(3)(i) For manufacturers calculating air conditioning efficiency
credits in support of fuel consumption improvement values under Sec.
600.510(c), a description of the air conditioning system and the total
credits earned for each averaging set, model year, and region, as
applicable.
(ii) Any additional fuel economy data submitted by the manufacturer
under Sec. 600.509;
* * * * *
Sec. 600.514-12 [Removed]
0
69. Remove Sec. 600.514-12.
PART 1036--CONTROL OF EMISSIONS FROM NEW AND IN-USE HEAVY-DUTY
HIGHWAY ENGINES
0
70. The authority citation for part 1036 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
0
71. Amend Sec. 1036.1 by revising paragraph (a) introductory text and
adding paragraph (e) to read as follows:
Sec. 1036.1 Applicability.
(a) Except as specified in Sec. 1036.5, the provisions of this
part apply for engines that will be installed in heavy-duty vehicles
(including glider vehicles). Heavy-duty engines produced before
December 20, 2026 are subject to exhaust emission standards for
NOX, HC, PM, and CO, and related provisions under 40 CFR
part 86, subpart A and subpart N, instead of this part, except as
follows:
* * * * *
(e) This part establishes criteria pollutant standards as described
in Sec. 1036.101. This part does not establish standards for
CO2 or other greenhouse gas emissions, but it includes
certification and testing provisions related to CO2
emissions to support the fuel consumption standards for heavy-duty
engines adopted by the Department of Transportation's National Highway
Traffic and Safety Administration (NHTSA) under 49 CFR part 535.
0
72. Amend Sec. 1036.5 by:
0
a. Revising paragraph (a); and
0
b. Removing paragraph (e).
The revision reads as follows:
Sec. 1036.5 Excluded engines.
(a) The provisions of this part do not apply to engines used in
medium-duty passenger vehicles or other heavy-duty vehicles that are
subject to regulation under 40 CFR part 86, subpart S, except as
specified in 40 CFR part 86, subpart S. For example, this exclusion
applies for engines used in incomplete vehicles or high-GCWR vehicles
certified to vehicle-based standards as described in 40 CFR 86.1801-12.
* * * * *
0
73. Amend Sec. 1036.15 by revising paragraph (b) to read as follows:
Sec. 1036.15 Other applicable regulations.
* * * * *
(b) Part 1037 of this chapter describes emission standards and
other requirements for heavy-duty vehicles, whether or not they use
engines certified under this part.
* * * * *
0
74. Amend Sec. 1036.101 by revising paragraph (a) to read as follows:
Sec. 1036.101 Overview of exhaust emission standards.
(a) You must show that engines meet the criteria pollutant
standards for NOX, HC, PM, and CO as described in Sec.
1036.104. These pollutants are sometimes described collectively as
``criteria pollutants'' because they are either criteria pollutants
under the Clean Air Act or precursors to the criteria pollutants ozone
and PM.
* * * * *
Sec. 1036.108 [Removed]
0
75. Remove Sec. 1036.108.
0
76. Amend Sec. 1036.110 by adding paragraphs (b)(14) through (18) to
read as follows:
Sec. 1036.110 Onboard diagnostics.
* * * * *
(b) * * *
(14) The definition of ``Active Technology'' in 13 CCR 1971.1(c)
does not apply.
(15) The standardization requirements in 13 CCR 1971.1(h)(5.4) do
not apply.
(16) The data storage requirements in 13 CCR 1971.1(h)(6.1) related
to the standardization requirements in 13 CCR 1971.1(h)(5.4) do not
apply.
(17) The certification documentation requirement related to
``Active Technology'' in 13 CCR 1971.1(j)(2.32) does not apply.
(18) The monitoring system demonstration requirements in 13 CCR
1971.1(i)(4.3.2)(C) related to CO2 emission data does not
apply.
* * * * *
0
77. Amend Sec. 1036.115 by revising paragraph (b) to read as follows:
Sec. 1036.115 Other requirements.
* * * * *
(b) Fuel mapping. Fuel mapping for your engine in support of
NHTSA's fuel consumption standards are described in Sec. 1036.505(b).
* * * * *
0
78. Amend Sec. 1036.130 by revising paragraph (b)(5) to read as
follows:
Sec. 1036.130 Installation instructions for vehicle manufacturers.
* * * * *
(b) * * *
(5) Describe how your certification is limited for any type of
application. For example, if you certify engines only for use in
emergency vehicles, you must make clear that the engine may only be
installed in emergency vehicles.
* * * * *
0
79. Amend Sec. 1036.135 by revising paragraph (c)(9) to read as
follows:
Sec. 1036.135 Labeling.
* * * * *
(c) * * *
(9) Identify any limitations on your certification. For example, if
you certify engines with one or more approved AECDs for emergency
vehicle applications under Sec. 1036.115(h)(4), include the statement:
``THIS ENGINE IS FOR INSTALLATION IN EMERGENCY VEHICLES ONLY''.
* * * * *
0
80. Revise and republish Sec. 1036.150 to read as follows:
Sec. 1036.150 Interim provisions.
The provisions in this section apply instead of other provisions in
this part. This section describes when these interim provisions expire,
if applicable.
(a) Transitional ABT credits for NOX emissions. You may generate
NOX credits from model year 2026 and earlier engines and use
those as transitional credits for model year 2027 and later engines
using any of the following methods:
(1) Discounted credits. Generate discounted credits by certifying
any model year 2022 through 2026 engine family to meet all the
requirements that apply under 40 CFR part 86, subpart A. Calculate
discounted credits for certifying engines in model years 2027 through
2029 as described in Sec. 1036.705 relative to a NOX
emission standard of 200 mg/hp[middot]hr and multiply the result by
0.6. You may not use discounted credits
[[Page 7776]]
for certifying model year 2030 and later engines.
(2) Partial credits. Generate partial credits by certifying any
model year 2024 through 2026 compression-ignition engine family as
described in this paragraph (a)(2). You may not use partial credits for
certifying model year 2033 and later engines. Certify engines for
partial credits to meet all the requirements that apply under 40 CFR
part 86, subpart A, with the following adjustments:
(i) Calculate credits as described in Sec. 1036.705 relative to a
NOX emission standard of 200 mg/hp[middot]hr using the
appropriate useful life mileage from 40 CFR 86.004-2. Your declared
NOX family emission limit applies for the FTP and SET duty
cycles.
(ii) Engines must meet a NOX standard when tested over
the Low Load Cycle as described in Sec. 1036.514. Engines must also
meet an off-cycle NOX standard as specified in Sec.
1036.104(a)(3). Calculate the NOX family emission limits for
the Low Load Cycle and for off-cycle testing as described in Sec.
1036.104(c)(3) with StdFTPNOx set to 35 mg/hp[middot]hr and
Std[cycle]NOx set to the values specified in Sec.
1036.104(a)(1) or (3), respectively. No standard applies for HC, PM,
and CO emissions for the Low Load Cycle or for off-cycle testing, but
you must record measured values for those pollutants and include those
measured values where you report NOX emission results.
(iii) For engines selected for in-use testing, we may specify that
you perform testing as described in 40 CFR part 86, subpart T, or as
described in subpart E of this part.
(iv) Add the statement ``Partial credit'' to the emission control
information label.
(3) Full credits. Generate full credits by certifying any model
year 2024 through 2026 engine family to meet all the requirements that
apply under this part. Calculate credits as described in Sec. 1036.705
relative to a NOX emission standard of 200 mg/hp[middot]hr.
You may not use full credits for certifying model year 2033 and later
engines.
(4) 2026 service class pull-ahead credits. Generate credits from
diesel-fueled engines under this paragraph (a)(4) by certifying all
your model year 2026 diesel-fueled Heavy HDE to meet all the
requirements that apply under this part, with a NOX family
emission limit for FTP testing at or below 50 mg/hp[middot]hr.
Calculate credits as described in Sec. 1036.705 relative to a
NOX emission standard of 200 mg/hp[middot]hr. You may use
credits generated under this paragraph (a)(4) through model year 2034,
but not for later model years. Credits generated by Heavy HDE may be
used for certifying Medium HDE after applying a 10 percent discount
(multiply credits by 0.9). Engine families using credits generated
under this paragraph (a)(4) are subject to a NOX FEL cap of
50 mg/hp[middot]hr for FTP testing.
(b) [Reserved]
(c) Engine cycle classification. Through model year 2020, engines
meeting the definition of spark-ignition, but regulated as compression-
ignition engines under Sec. 1036.140, must be certified to the
requirements applicable to compression-ignition engines under this
part. Such engines are deemed to be compression-ignition engines for
purposes of this part. Similarly, through model year 2020, engines
meeting the definition of compression-ignition, but regulated as Otto-
cycle under 40 CFR part 86 must be certified to the requirements
applicable to spark-ignition engines under this part. Such engines are
deemed to be spark-ignition engines for purposes of this part. See
Sec. 1036.140 for provisions that apply for model year 2021 and later.
(d) Small manufacturers. The fuel consumption standards under 49
CFR part 535 apply on a delayed schedule for manufacturers meeting the
small business criteria specified in 13 CFR 121.201. Apply the small
business criteria for NAICS code 336310 for engine manufacturers with
respect to gasoline-fueled engines and 333618 for engine manufacturers
with respect to other engines; the employee limits apply to the total
number employees together for affiliated companies. Qualifying small
manufacturers are not subject to the fuel consumption standards for
engines with a date of manufacture on or after November 14, 2011, but
before January 1, 2022. In addition, qualifying small manufacturers
producing engines that run on any fuel other than gasoline, E85, or
diesel fuel may delay complying with every later fuel consumption
standard under 49 CFR part 535 by one model year; however, small
manufacturers may generate credits only by certifying all their engine
families within a given averaging set to standards that apply for the
current model year. Note that engines not yet subject to standards must
nevertheless supply fuel maps to vehicle manufacturers as described in
paragraph (n) of this section. Note also that engines produced by small
manufacturers are subject to criteria pollutant standards.
(e) [Reserved]
(f) Testing exemption for hydrogen engines. Tailpipe HC, and CO
emissions from engines fueled with neat hydrogen are deemed to comply
with the applicable standard. Testing for HC or CO is optional under
this part for these engines.
(g)-(j) [Reserved]
(k) Limited production volume allowance under ABT. You may produce
a limited number of Heavy HDE that continue to meet the standards that
applied under 40 CFR 86.007-11 in model years 2027 through 2029. The
maximum number of engines you may produce under this limited production
allowance is 5 percent of the annual average of your actual production
volume of Heavy HDE in model years 2023-2025 for calculating emission
credits under Sec. 1036.705. Engine certification under this paragraph
(k) is subject to the following conditions and requirements:
(1) Engines must meet all the standards and other requirements that
apply under 40 CFR part 86 for model year 2026. Engine must be
certified in separate engine families that qualify for carryover
certification as described in Sec. 1036.235(d).
(2) The NOX FEL must be at or below 200 mg/hp[middot]hr.
Calculate negative credits as described in Sec. 1036.705 by comparing
the NOX FEL to the FTP emission standard specified in Sec.
1036.104(a)(1), with a value for useful life of 650,000 miles. Meet the
credit reporting and recordkeeping requirements in Sec. Sec. 1036.730
and 1036.735.
(3) Label the engine as described in 40 CFR 86.095-35, but include
the following alternate compliance statement: ``THIS ENGINE CONFORMS TO
U.S. EPA REGULATIONS FOR MODEL YEAR 2026 ENGINES UNDER 40 CFR
1036.150(k).''
(l) [Reserved]
(m) Infrequent regeneration. For model year 2020 and earlier, you
may invalidate any test interval with respect to CO2
measurements if an infrequent regeneration event occurs during the test
interval. Note that Sec. 1036.580 specifies how to apply infrequent
regeneration adjustment factors for later model years.
(n) Supplying fuel maps. Engine manufacturers not yet subject to
fuel consumption standards under 49 CFR part 535 in model year 2021
must supply vehicle manufacturers with fuel maps (or powertrain test
results) as described in Sec. 1036.130 for those engines.
(o) Engines used in glider vehicles. For purposes of recertifying a
used engine for installation in a glider vehicle, we may allow you to
include in an existing certified engine family those engines you modify
(or otherwise demonstrate) to be identical to engines already covered
by the certificate. We
[[Page 7777]]
would base such an approval on our review of any appropriate
documentation. These engines must have emission control information
labels that accurately describe their status.
(p) [Reserved]
(q) Confirmatory and in-use testing of fuel maps defined in Sec.
1036.505(b). For model years 2021 and later, where the results from Eq.
1036.235-1 for a confirmatory or in-use test are at or below 2.0%, we
will not replace the manufacturer's fuel maps.
(r) Fuel maps for the transition to updated GEM. (1) You may use
fuel maps from model year 2023 and earlier engines for certifying model
year 2024 and later engines using carryover provisions in Sec.
1036.235(d).
(2) Compliance testing will be based on the GEM version you used to
generate fuel maps for certification. For example, if you perform a
selective enforcement audit with respect to fuel maps, use the same GEM
version that you used to generate fuel maps for certification.
Similarly, we will use the same GEM version that you used to generate
fuel maps for certification if we perform confirmatory testing with one
of your engine families.
(s) Fuel consumption compliance testing. Select duty cycles and
measure emissions to demonstrate compliance with the fuel consumption
standards under 49 CFR part 535 before model year 2027 as follows:
(1) For model years 2016 through 2020, measure emissions using the
FTP duty cycle specified in Sec. 1036.512 and the SET duty cycle
specified in 40 CFR 86.1362, as applicable.
(2) The following provisions apply for model years 2021 through
2026:
(i) [Reserved]
(ii) You may demonstrate compliance with SET-based fuel consumption
standards using the SET duty cycle specified in 40 CFR 86.1362 if you
collect emissions with continuous sampling. Integrate the test results
by mode to establish separate emission rates for each mode (including
the transition following each mode, as applicable). Apply the
CO2 weighting factors specified in 40 CFR 86.1362 to
calculate a composite emission result.
(t) Model year 2027 compliance date. The following provisions
describe when this part 1036 starts to apply for model year 2027
engines:
(1) Split model year. Model year 2027 engines you produce before
December 20, 2026 are subject to the criteria standards and related
provisions in 40 CFR part 86, subpart A, as described in Sec.
1036.1(a). Model year 2027 engines you produce on or after December 20,
2026 are subject to all the provisions of this part.
(2) Optional early compliance. You may optionally certify model
year 2027 engines you produce before December 20, 2026 to all the
provisions of this part.
(3) Certification. If you certify any model year 2027 engines to 40
CFR part 86, subpart A, under paragraph (t)(1) of this section, certify
the engine family by dividing the model year into two partial model
years. The first portion of the model year starts when it would
normally start and ends when you no longer produce engines meeting
standards under 40 CFR part 86, subpart A, on or before December 20,
2026. The second portion of the model year starts when you begin
producing engines meeting standards under this part 1036, and ends on
the day your model year would normally end. The following additional
provisions apply for model year 2027 if you split the model year as
described in this paragraph (t):
(i) You may generate emission credits only with engines that are
certified under this part 1036.
(ii) In your production report under Sec. 1036.250(a), identify
production volumes separately for the two parts of the model year.
(iii) OBD testing demonstrations apply singularly for the full
model year.
(u) Crankcase emissions. The provisions of 40 CFR 86.007-11(c) for
crankcase emissions continue to apply through model year 2026.
(v) OBD communication protocol. We may approve the alternative
communication protocol specified in SAE J1979-2 (incorporated by
reference, see Sec. 1036.810) if the protocol is approved by the
California Air Resources Board. The alternative protocol would apply
instead of SAE J1939 and SAE J1979 as specified in 40 CFR 86.010-
18(k)(1). Engines designed to comply with SAE J1979-2 must meet the
freeze-frame requirements in Sec. 1036.110(b)(8) and in 13 CCR
1971.1(h)(4.3.2) (incorporated by reference, see Sec. 1036.810). This
paragraph (v) also applies for model year 2026 and earlier engines.
(w) [Reserved]
(x) Powertrain testing for criteria pollutants. You may apply the
powertrain testing provisions of Sec. 1036.101(b) for demonstrating
compliance with criteria pollutant emission standards in 40 CFR part 86
before model year 2027.
(y) NOX compliance allowance for in-use testing. A NOX
compliance allowance of 15 mg/hp[middot]hr applies for any in-use
testing of Medium HDE and Heavy HDE as described in subpart E of this
part. Add the compliance allowance to the NOX standard that
applies for each duty cycle and for off-cycle testing, with both field
testing and laboratory testing. The NOX compliance allowance
does not apply for the bin 1 off-cycle standard. As an example, for
manufacturer-run field-testing of a Heavy HDE, add the 15 mg/
hp[middot]hr compliance allowance and the 5 mg/hp[middot]hr accuracy
margin from Sec. 1036.420 to the 58 mg/hp[middot]hr bin 2 off-cycle
standard to calculate a 78 mg/hp[middot]hr NOX standard.
(z) Alternate family pass criteria for in-use testing. The
following family pass criteria apply for manufacturer-run in-use
testing instead of the pass criteria described in Sec. 1036.425 for
model years 2027 and 2028:
(1) Start by measuring emissions from five engines using the
procedures described in subpart E of this part and Sec. 1036.530. If
four or five engines comply fully with the off-cycle bin standards, the
engine family passes and you may stop testing.
(2) If exactly two of the engines tested under paragraph (z)(1) of
this section do not comply fully with the off-cycle bin standards, test
five more engines. If these additional engines all comply fully with
the off-cycle bin standards, the engine family passes and you may stop
testing.
(3) If three or more engines tested under paragraphs (z)(1) and (2)
of this section do not comply fully with the off-cycle bin standards,
test a total of at least 10 but not more than 15 engines. Calculate the
arithmetic mean of the bin emissions from all the engine tests as
specified in Sec. 1036.530(g) for each pollutant. If the mean values
are at or below the off-cycle bin standards, the engine family passes.
If the mean value for any pollutant is above an off-cycle bin standard,
the engine family fails.
0
81. Amend Sec. 1036.205 by:
0
a. Revising paragraphs (b) introductory text, (l), (m), (o)(2), and
(t); and
0
b. Removing paragraph (aa).
The revisions read as follows:
Sec. 1036.205 Requirements for an application for certification.
* * * * *
(b) Explain how the emission control system operates. Describe in
detail all system components for controlling greenhouse gas and
criteria pollutant emissions, including all auxiliary emission control
devices (AECDs) and all fuel-system components you will install on any
production or test engine. Identify the part number of each component
you describe. For this paragraph (b), treat as separate AECDs
[[Page 7778]]
any devices that modulate or activate differently from each other.
Include all the following:
* * * * *
(l) Identify the duty-cycle emission standards from Sec.
1036.104(a) and (b) that apply for the engine family. Also identify
FELs and FCLs as follows:
(1) Identify the NOX FEL over the FTP for the engine
family.
(2) Identify the CO2 FCLs for the engine family. The
actual U.S.-directed production volume of configurations that are at or
below the FCL must be at least one percent of your actual (not
projected) U.S.-directed production volume for the engine family.
Identify configurations within the family that have emission rates at
or below the FCL and meet the one percent requirement. For example, if
your U.S.-directed production volume for the engine family is 10,583
and the U.S.-directed production volume for the tested rating is 75
engines, then you can comply with this provision by setting your FCL so
that one more rating with a U.S.-directed production volume of at least
31 engines meets the FCL. Where applicable, also identify other
testable configurations required under Sec. 1036.230(f)(2)(ii).
(m) Identify the engine family's deterioration factors and describe
how you developed them (see Sec. 1036.240). Present any test data you
used for this. For engines designed to discharge crankcase emissions to
the ambient atmosphere, use the deterioration factors for crankcase
emission to determine deteriorated crankcase emission levels of
NOX, HC, PM, and CO as specified in Sec. 1036.240(e).
* * * * *
(o) * * *
(2) Identify the value of eCO2FTPFCL from Sec.
1036.235(b). Show emission figures before and after applying
deterioration factors for each engine. In addition to the composite
results, show individual measurements for cold-start testing and hot-
start testing over the transient test cycle.
* * * * *
(t) State whether your certification is limited for certain
engines. For example, you might certify engines only for use in
emergency vehicles or in vehicles with hybrid powertrains. If this is
the case, describe how you will prevent use of these engines in
vehicles for which they are not certified.
* * * * *
0
82. Amend Sec. 1036.230 by revising paragraphs (f) introductory text,
and (f)(1) and (5) to read as follows:
Sec. 1036.230 Selecting engine families.
* * * * *
(f) The following additional provisions apply with respect to
demonstrating compliance with the fuel consumption standards of 49 CFR
535.5:
(1) Use the same engine families you use for criteria pollutants.
You may subdivide an engine family into subfamilies that have a
different FCL for CO2 emissions. These subfamilies do not
apply for demonstrating compliance with criteria standards in Sec.
1036.104.
* * * * *
(5) Except as described in this paragraph (f), engine
configurations within an engine family must use equivalent controls.
Unless we approve it, you may not produce nontested configurations
without the same control hardware included on the tested configuration.
* * * * *
0
83. Add Sec. 1036.231 to subpart C to read as follows:
Sec. 1036.231 Powertrain families.
(a) If you choose to perform powertrain testing as specified in
Sec. 1036.545, use good engineering judgment to divide your product
line into powertrain families that are expected to have similar
criteria emissions throughout the useful life as described in this
section. Your powertrain family is limited to a single model year.
(b) Except as specified in paragraph (c) of this section, group
powertrains in the same powertrain family if they share all the
following attributes:
(1) Have the same engine design aspects as specified in Sec.
1036.230.
(2) [Reserved]
(3) Number of clutches.
(4) Type of clutch (e.g., wet or dry).
(5) Presence and location of a fluid coupling such as a torque
converter.
(6) Gear configuration, as follows:
(i) Planetary (e.g., simple, compound, meshed-planet, stepped-
planet, multi-stage).
(ii) Countershaft (e.g., single, double, triple).
(iii) Continuously variable (e.g., pulley, magnetic, toroidal).
(7) Number of available forward gears, and transmission gear ratio
for each available forward gear, if applicable. Count forward gears as
being available only if the vehicle has the hardware and software to
allow operation in those gears.
(8) Transmission oil sump configuration (e.g., conventional or
dry).
(9) The power transfer configuration of any hybrid technology
(e.g., series or parallel).
(10) The type of any RESS (e.g., hydraulic accumulator, Lithium-ion
battery pack, ultracapacitor bank).
(c) For powertrains that share all the attributes described in
paragraph (b) of this section, divide them further into separate
powertrain families based on common calibration attributes. Group
powertrains in the same powertrain family to the extent that powertrain
test results and corresponding emission levels are expected to be
similar throughout the useful life.
(d) You may subdivide a group of powertrains with shared attributes
under paragraph (b) of this section into different powertrain families.
(e) In unusual circumstances, you may group powertrains into the
same powertrain family even if they do not have shared attributes under
in paragraph (b) of this section if you show that their emission
characteristics throughout the useful life will be similar.
(f) If you include the axle when performing powertrain testing for
the family, you must limit the family to include only those axles
represented by the test results. You may include multiple axle ratios
in the family if you test with the axle expected to produce the highest
emission results.
0
84. Amend Sec. 1036.235 by revising the introductory text and
paragraphs (a), (b), and (c)(5) introductory text to read as follows:
Sec. 1036.235 Testing requirements for certification.
This section describes the emission testing you must perform to
show compliance with the emission standards in Sec. 1036.104 or fuel
consumption standards under 49 CFR part 535.
(a) Select and configure one or two emission-data engines from each
engine family as follows:
(1) You may use one engine for criteria pollutant testing and a
different engine for fuel consumption testing, or you may use the same
engine for all testing.
(2) For criteria pollutant emission testing, select the engine
configuration with the highest volume of fuel injected per cylinder per
combustion cycle at the point of maximum torque--unless good
engineering judgment indicates that a different engine configuration is
more likely to exceed (or have emissions nearer to) an applicable
emission standard or FEL. If two or more engines have the same fueling
rate at maximum torque, select the one with the highest fueling rate at
rated speed. In making this selection, consider all factors expected to
affect emission-control performance and compliance with the
[[Page 7779]]
standards, including emission levels of all exhaust constituents,
especially NOX and PM. To the extent we allow it for
establishing deterioration factors, select for testing those engine
components or subsystems whose deterioration best represents the
deterioration of in-use engines.
(3) For fuel consumption testing, the standards of this part apply
only with respect to emissions measured from the tested configuration
and other configurations identified in Sec. 1036.205(l)(2). Note that
configurations identified in Sec. 1036.205(l)(2) are considered to be
``tested configurations'' whether or not you test them for
certification. However, you must apply the same (or equivalent)
emission controls to all other engine configurations in the engine
family. In other contexts, the tested configuration is sometimes
referred to as the ``parent configuration'', although the terms are not
synonymous.
(4) In the case of powertrain testing under Sec. 1036.545, select
a test engine, test hybrid components, test axle and test transmission
as applicable, by considering the whole range of vehicle models covered
by the powertrain family. If the powertrain has more than one
transmission calibration, for example economy vs. performance, you may
weight the results from the powertrain testing in Sec. 1036.545 by the
percentage of vehicles in the family by prior model year for each
configuration. This can be done, for example, through the use of survey
data or based on the previous model year's sales volume. Weight the
results of Mfuel[cycle], fnpowertrain/
vpowertrain, and W[cycle] from table 5 to
paragraph (o)(8)(i) of Sec. 1036.545 according to the percentage of
vehicles in the family that use each transmission calibration.
(b) Test your emission-data engines using the procedures and
equipment specified in subpart F of this part. In the case of dual-fuel
and flexible-fuel engines, measure emissions when operating with each
type of fuel for which you intend to certify the engine.
(1) For criteria pollutant emission testing, measure
NOX, PM, CO, and NMHC emissions using each duty cycle
specified in Sec. 1036.104. Note that off-cycle testing depends on
determining the value of eCO2FTPFCL from Sec. 1036.530.
(2) For fuel consumption testing, measure CO2 emissions;
the following provisions apply regarding test cycles for demonstrating
compliance with tractor and vocational fuel consumption standards:
(i) For tractors, you must measure CO2 emissions using
the SET duty cycle specified in Sec. 1036.510, taking into account the
interim provisions in Sec. 1036.150(s).
(ii) For vocational applications, you must measure CO2
emissions using the appropriate FTP transient duty cycle, including
cold-start and hot-start testing as specified in Sec. 1036.512.
(iii) For engine families that include both tractor and vocational
use, you may submit CO2 emission data and specify FCLs for
both SET and FTP transient duty cycles.
(iv) Some of your engines tested for use in tractors may also be
used in vocational vehicles, and some of your engines tested for use in
vocational may be used in tractors. However, you may not knowingly
circumvent the intent of this part by testing engines designed for
tractors or vocational vehicles (and rarely used in the other
application) to the wrong cycle.
(c) * * *
(5) For fuel consumption testing, we may use our emission test
results for steady-state, idle, cycle-average and powertrain fuel maps
defined in Sec. 1036.505(b) as the official emission results. We will
not replace individual points from your fuel map.
* * * * *
Sec. 1036.241 [Removed]
0
85. Remove Sec. 1036.241.
0
86. Amend Sec. 1036.301 by revising the section heading to read as
follows:
Sec. 1036.301 Selective enforcement audits.
* * * * *
0
87. Amend Sec. 1036.501 by revising paragraph (a) to read as follows:
Sec. 1036.501 General testing provisions.
(a) Use the equipment and procedures specified in this subpart and
40 CFR part 1065 to determine whether engines meet the emission
standards in Sec. 1036.104 or fuel consumption standards under 49 CFR
part 535.
* * * * *
0
88. Add Sec. 1036.503 to subpart F to read as follows:
Sec. 1036.503 Engine data and information to support vehicle
certification for NHTSA.
See Sec. 1036.505 for engine data and information required to
support vehicle certification.
0
89. Amend Sec. 1036.505 by revising the introductory text and
paragraph (a) to read as follows:
Sec. 1036.505 Engine data and information to support vehicle
certification.
You must give vehicle manufacturers information as follows so they
can certify their vehicles to fuel consumption standards under 49 CFR
part 535:
(a) Identify engine make, model, fuel type, combustion type, engine
family name, calibration identification, and engine displacement. Also
identify whether the engines will be used in tractors, vocational
vehicles, or both. When certifying vehicles with GEM, for any fuel type
not identified in table 1 to paragraph (b)(4) of Sec. 1036.550,
identify the fuel type as diesel fuel for engines subject to
compression-ignition standards, and as gasoline for engines subject to
spark-ignition standards.
* * * * *
0
90. Amend Sec. 1036.510 by revising paragraphs (b)(2) introductory
text and (b)(2)(vii) and (viii) to read as follows:
Sec. 1036.510 Supplemental Emission Test.
* * * * *
(b) * * *
(2) Test hybrid powertrains as described in Sec. 1036.545, except
as specified in this paragraph (b)(2). Do not compensate the duty cycle
for the distance driven as described in Sec. 1036.545(g)(4). For
hybrid engines, select the transmission model parameters as described
in Sec. 1036.510(b)(2)(viii), . Disregard duty cycles in Sec.
1036.545(j). For cycles that begin with idle, leave the transmission in
neutral or park for the full initial idle segment. Place the
transmission into drive no earlier than 5 seconds before the first
nonzero vehicle speed setpoint. For SET testing only, place the
transmission into park or neutral when the cycle reaches the final idle
segment. Use the following vehicle parameters instead of those in Sec.
1036.545 to define the vehicle model in Sec. 1036.545(a)(3):
* * * * *
(vii) Select a combination of drive axle ratio, ka, and
a tire radius, r, that represents the worst-case combination of top
gear ratio, drive axle ratio, and tire size for CO2
emissions expected for vehicles in which the hybrid engine or hybrid
powertrain will be installed. This is typically the highest axle ratio
and smallest tire radius. Disregard configurations or settings
corresponding to a maximum vehicle speed below 60 mi/hr in selecting a
drive axle ratio and tire radius, unless you can demonstrate that in-
use vehicles will not exceed that speed. You may request preliminary
approval for selected drive axle ratio and tire radius consistent with
the provisions of Sec. 1036.210. If the hybrid engine or hybrid
powertrain is used exclusively in vehicles not capable of reaching 60
mi/hr, you may request that we approve an alternate test cycle and
cycle-validation criteria as described in 40 CFR 1066.425(b)(5). Note
that hybrid engines rely on a specified transmission
[[Page 7780]]
that is different for each duty cycle; the transmission's top gear
ratio therefore depends on the duty cycle, which will in turn change
the selection of the drive axle ratio and tire size. For example, Sec.
1036.520 prescribes a different top gear ratio than this paragraph
(b)(2).
(viii) If you are certifying a hybrid engine, use a default
transmission efficiency of 0.95 and create the vehicle model along with
its default transmission shift strategy as described in Sec.
1036.545(a)(3)(ii). Specify the transmission type as Automatic
Transmission for all engines and for all duty cycles, except that the
transmission type is Automated Manual Transmission for Heavy HDE
operating over the SET duty cycle. For automatic transmissions set
neutral idle to ``Y'' in the vehicle file. Select gear ratios for each
gear as shown in the following table:
Table 1 to Paragraph (b)(2)(viii) of Sec. 1036.510--GEM HIL Input for Gear Ratio
----------------------------------------------------------------------------------------------------------------
Spark-ignition HDE,
Gear No. Light HDE, and Medium Heavy HDE--LLC and FTP Heavy HDE-- SET duty
HDE--all duty cycles duty cycles cycle
----------------------------------------------------------------------------------------------------------------
1.................................... 3.10 3.51 12.8
2.................................... 1.81 1.91 9.25
3.................................... 1.41 1.43 6.76
4.................................... 1.00 1.00 4.90
5.................................... 0.71 0.74 3.58
6.................................... 0.61 0.64 2.61
7.................................... ....................... ....................... 1.89
8.................................... ....................... ....................... 1.38
9.................................... ....................... ....................... 1.00
10................................... ....................... ....................... 0.73
Lockup Gear.......................... 3 3 .......................
----------------------------------------------------------------------------------------------------------------
* * * * *
0
91. Amend Sec. 1036.512 by revising paragraphs (b)(2)(iv) and (e) to
read as follows:
Sec. 1036.512 Federal Test Procedure.
* * * * *
(b) * * *
(2) * * *
(iv) For plug-in hybrid powertrains, test over the FTP in both
charge-sustaining and charge-depleting operation for criteria pollutant
determination.
* * * * *
(e) Determine CO2 emissions for plug-in hybrid engines
and powertrains using the emissions results for all the transient duty
cycle test intervals described in either paragraph (b) or (c) of
appendix B to this part for both charge-depleting and charge-sustaining
operation from paragraph (d)(2) of this section. Calculate the utility
factor weighted composite mass of emissions from the charge-depleting
and charge-sustaining test results, eUF[emission]comp, as
described in Sec. 1036.510(e), replacing occurrences of ``SET'' with
``transient test interval''. Note this results in composite FTP
CO2 emission results for plug-in hybrid engines and
powertrains without the use of the cold-start and hot-start test
interval weighting factors in Eq. 1036.512-1.
* * * * *
0
92. Amend Sec. 1036.514 by revising paragraph (b)(4) to read as
follows:
Sec. 1036.514 Low Load Cycle.
* * * * *
(b) * * *
(4) Adjust procedures in this section as described in Sec.
1036.510(d) for plug-in hybrid powertrains, replacing ``SET'' with
``LLC''. Note that the LLC is therefore the preconditioning duty cycle
for plug-in hybrid powertrains.
* * * * *
0
93. Amend Sec. 1036.520 by revising paragraph (b)(1) to read as
follows:
Sec. 1036.520 Determining power and vehicle speed values for
powertrain testing.
* * * * *
(b) * * *
(1) Use vehicle parameters, other than power, as specified in Sec.
1036.510(b)(2). Use the applicable automatic transmission as specified
in Sec. 1036.510(b)(2)(viii).
* * * * *
0
94. Amend Sec. 1036.535 by:
0
a. Revising the introductory text; and
0
b. Removing and reserving paragraph (f).
The revision reads as follows:
Sec. 1036.535 Determining steady-state engine fuel maps and fuel
consumption at idle.
The procedures in this section describe how to determine an
engine's steady-state fuel map and fuel consumption at idle for model
year 2021 and later vehicles; these procedures apply as described in
Sec. 1036.505. Vehicle manufacturers may need these values to
demonstrate compliance with standards under 49 CFR part 535.
* * * * *
0
95. Amend Sec. 1036.540 by:
0
a. Revising paragraph (a) introductory text; and
0
b. Removing and reserving paragraph (b)(1).
The revision reads as follows:
Sec. 1036.540 Determining cycle-average engine fuel maps.
(a) Overview. This section describes how to determine an engine's
cycle-average fuel maps for model year 2021 and later vehicles. Vehicle
manufacturers may need cycle-average fuel maps for transient duty
cycles, highway cruise cycles, or both to demonstrate compliance with
standards under 49 CFR part 535. Generate cycle-average engine fuel
maps as follows:
* * * * *
0
96. Amend Sec. 1036.545 by:
0
a. Revising the introductory text;
0
b. Removing and reserving paragraph (a)(1);
0
c. Revising paragraph (d); and
0
d. Removing paragraph (p).
The revisions read as follows:
Sec. 1036.545 Powertrain testing.
This section describes the procedure to measure fuel consumption
and create engine fuel maps by testing a powertrain that includes an
engine coupled with a transmission, drive axle, and hybrid components
or any assembly with one or more of those hardware elements. Engine
fuel maps are part of demonstrating compliance with standards under 49
CFR part 535; the powertrain test procedure in this section is one
option for generating this fuel-mapping information as described in
Sec. 1036.505. Additionally, this powertrain test procedure is one
option
[[Page 7781]]
for certifying hybrid powertrains to the engine standards in Sec.
1036.104.
* * * * *
(d) Powertrain break in. Break in the powertrain as a complete
system using the engine break-in procedure in 40 CFR 1065.405(c), or
take the following steps to break in the engine, axle assembly, and
transmission separately, as applicable:
(1) Break in the engine according to 40 CFR 1065.405(c).
(2) Break in the axle assembly using good engineering judgment.
Maintain gear oil temperature at or below 100 [deg]C throughout the
break-in period.
(3) Break in the transmission using good engineering judgment.
Maintain transmission oil temperature at (87 to 93) [deg]C for
automatic transmissions and transmissions having more than two friction
clutches, and at (77 to 83) [deg]C for all other transmissions. You may
ask us to approve a different range of transmission oil temperatures if
you have data showing that it better represents in-use operation.
* * * * *
0
97. Amend Sec. 1036.550 by revising the section heading and
introductory text to read as follows:
Sec. 1036.550 Calculating CO2 emission rates.
This section describes how to calculate official emission results
for CO2.
* * * * *
0
98. Amend Sec. 1036.580 by revising the introductory text and
paragraph (c) to read as follows:
Sec. 1036.580 Infrequently regenerating aftertreatment devices.
For engines using aftertreatment technology with infrequent
regeneration events that may occur during testing, take one of the
following approaches to account for the emission impact of
regeneration:
* * * * *
(c) You may choose to make no adjustments to measured emission
results if you determine that regeneration does not significantly
affect emission levels for an engine family (or configuration) or if it
is not practical to identify when regeneration occurs. You may omit
adjustment factors under this paragraph (c) for individual pollutants
under this paragraph (c) as appropriate. If you choose not to make
adjustments under paragraph (a) or (b) of this section, your engines
must meet emission standards for all testing, without regard to
regeneration.
* * * * *
0
99. Amend Sec. 1036.605 by revising paragraphs (b) and (g) to read as
follows:
Sec. 1036.605 Alternate emission standards for engines used in
specialty vehicles.
* * * * *
(b) Compression-ignition engines must be of a configuration that is
identical to one that is certified under 40 CFR part 1039, and must be
certified with a family emission limit for PM of 0.020 g/kW-hr using
the same duty cycles that apply under 40 CFR part 1039.
* * * * *
(g) Engines certified under this section may not generate or use
emission credits under this part or under 40 CFR part 1039.
0
100. Amend Sec. 1036.610 by revising the section heading to read as
follows:
Sec. 1036.610 Off-cycle technology credits.
* * * * *
0
101. Amend Sec. 1036.620 by:
0
a. Revising the section h[middot]eading, introductory text, and
paragraph (a); and
0
b. Removing and reserving paragraphs (d) and (e).
The revisions read as follows:
Sec. 1036.620 Alternate standards based on model year 2011
compression-ignition engines.
For model years 2014 through 2016, you may certify your
compression-ignition engines to alternate fuel consumption standards as
described in this section. However, you may not certify engines to
these alternate standards if they are part of an averaging set in which
you carry a balance of banked credits. For purposes of this section,
you are deemed to carry credits in an averaging set if you carry
credits from advanced technology that are allowed to be used in that
averaging set.
(a) The standards of this section are determined from the measured
emission rate of the engine of the applicable baseline 2011 engine
family or families as described in paragraphs (b) and (c) of this
section. Calculate the CO2 emission rate of the baseline
engine using the same equations used for showing compliance with the
otherwise applicable fuel consumption standard. The alternate emission
rate for light and medium heavy-duty vocational-certified engines
(using the transient cycle) is equal to the baseline emission rate
multiplied by 0.975. The alternate emission rate for tractor-certified
engines (using the SET duty cycle) and all other Heavy HDE is equal to
the baseline emission rate multiplied by 0.970. The in-use FEL for
these engines is equal to the alternate standard multiplied by 1.03.
* * * * *
Sec. 1036.625 [Removed]
0
102. Remove Sec. 1036.625.
0
103. Revise and republish Sec. 1036.630 to read as follows:
Sec. 1036.630 Measurement of CO2 emissions for powertrain testing.
For engines included in powertrain families under Sec. 1036.231,
you may choose to include the corresponding engine emissions in your
engine families under this part instead of (or in addition to) the
otherwise applicable engine fuel maps.
(a) If you choose to certify powertrain fuel maps in an engine
family for fuel consumption standards, the declared values for
powertrain testing become the standards that apply for selective
enforcement audits and in-use testing. We may require that you provide
to us the engine cycle (not normalized) corresponding to a given
powertrain for each of the specified duty cycles.
(b) If you choose to certify only fuel map values for an engine
family for fuel consumption standards and to not certify values over
powertrain cycles under Sec. 1036.545, we will not presume you are
responsible for value over the powertrain cycles. However, where we
determine that you are responsible in whole or in part for the emission
exceedance in such cases, we may require that you participate in any
recall of the affected vehicles.
(c) If you split an engine family into subfamilies based on
different fuel-mapping procedures as described in Sec. 1036.230(f)(2),
the fuel-mapping procedures you identify for certifying each subfamily
also apply for selective enforcement audits and in-use testing.
Sec. 1036.635 [Removed]
0
104. Remove Sec. 1036.635.
0
105. Amend Sec. 1036.701 by:
0
a. Revising paragraph (a); and
0
b. Removing and reserving paragraphs (h) through (j).
The revisions read as follows:
Sec. 1036.701 General provisions.
(a) You may average, bank, and trade (ABT) emission credits for
purposes of certification as described in this subpart and in subpart B
of this part to show compliance with the standards of Sec. Sec.
1036.104. Participation in this program is voluntary. Note that
certification to NOX standards in Sec. 1036.104 is based on
a family emission limit (FEL) the NHTSA fuel efficiency program under
49 CFR part 535 is based on a Family Certification Level (FCL).
[[Page 7782]]
This part refers to ``FEL/FCL'' to simultaneously refer to FELs for
NOX and FCLs for NHTSA. Note also that subpart B of this
part requires you to assign an FCL to all engine families, whether or
not they participate in the ABT provisions of this subpart.
* * * * *
0
106. Revise Sec. 1036.705 to read as follows:
Sec. 1036.705 Generating and calculating emission credits.
(a) The provisions of this section apply for calculating
NOX emission credits.
(b) For each participating family, calculate positive or negative
emission credits relative to the otherwise applicable emission
standard. Calculate positive emission credits for a family that has an
FEL below the standard. Calculate negative emission credits for a
family that has an FEL above the standard. Sum your positive and
negative credits for the model year before rounding. Calculate emission
credits to the nearest megagram (Mg) for each family using the
following equation:
Emission credits (Mg) = (Std-FL) [middot] CF [middot] Volume [middot]
UL [middot] c Eq. 1036.705-1
Where:
Std = the emission standard, in (mg NOX)/hp[middot]hr
that applies under subpart B of this part for engines not
participating in the ABT program of this subpart (the ``otherwise
applicable standard'').
FL = the engine family's FEL, in mg/hp[middot]hr, rounded to the
same number of decimal places as the emission standard.
CF = a transient cycle conversion factor (hp[middot]hr/mile),
calculated by dividing the total (integrated) horsepower-hour over
the applicable duty cycle by 6.3 miles for engines subject to spark-
ignition standards and 6.5 miles for engines subject to compression-
ignition standards. This represents the average work performed over
the duty cycle.
Volume = the number of engines eligible to participate in the
averaging, banking, and trading program within the given engine
family during the model year, as described in paragraph (c) of this
section.
UL = the useful life for the standard that applies for a given
primary intended service class, in miles.
c = 10-9.
Example for model year 2028 Heavy HDE generating NOX credits:
Std = 35 mg/hp[middot]hr
FEL = 20 mg/hp[middot]hr
CF = 9.78 hp[middot]hr/mile
Volume = 15,342
UL = 650,000 miles
c = 10-9
Emission credits = (35-20) [middot] 9.78 [middot] 15,342 [middot]
650,000 [middot] 10-9
Emission credits = 1,463 Mg
(c) Compliance with the requirements of this subpart is determined
at the end of the model year by calculating emission credits based on
actual production volumes, excluding the following engines:
(1) Engines that you do not certify to the standards of this part
because they are permanently exempted under subpart G of this part or
under 40 CFR part 1068.
(2) Exported engines.
(3) Engines not subject to the requirements of this part, such as
those excluded under Sec. 1036.5.
(4) Engines certified to state emission standards that are
different than the emission standards referenced in this section, and
intended for sale in a state that has adopted those emission standards.
(5) Any other engines if we indicate elsewhere in this part that
they are not to be included in the calculations of this subpart.
0
107. Amend Sec. 1036.710 by revising paragraph (b) to read as follows:
Sec. 1036.710 Averaging.
* * * * *
(b) You may certify one or more engine families to an FEL/FCL above
the applicable standard, subject to any applicable FEL caps and other
the provisions in subpart B of this part, if you show in your
application for certification that your projected balance of all
emission-credit transactions in that model year is greater than or
equal to zero, or that a negative balance is allowed under Sec.
1036.745 for NHTSA's fuel efficiency program.
* * * * *
0
108. Amend Sec. 1036.720 by revising paragraph (c) to read as follows:
Sec. 1036.720 Trading.
* * * * *
(c) If a negative emission credit balance results from a
transaction, both the buyer and seller are liable, except in cases we
deem to involve fraud. See Sec. 1036.255(e) for cases involving fraud.
We may void the certificates of all engine families participating in a
trade that results in a manufacturer having a negative balance of
emission credits. See Sec. 1036.745 for NHTSA's fuel efficiency
program.
0
109. Amend Sec. 1036.725 by revising paragraph (b)(1) to read as
follows:
Sec. 1036.725 Required information for certification.
* * * * *
(b) * * *
(1) A statement that, to the best of your belief, you will not have
a negative balance of emission credits for any averaging set when all
emission credits are calculated at the end of the year. For NHTSA's
fuel efficiency program, you may include a statement that you will have
a negative balance of emission credits for one or more averaging sets,
but that it is allowed under Sec. 1036.745.
* * * * *
0
110. Amend Sec. 1036.730 by revising paragraphs (c)(1) and (f)(1) to
read as follows:
Sec. 1036.730 ABT reports.
* * * * *
(c) * * *
(1) Show that your net balance of emission credits from all your
participating engine families in each averaging set in the applicable
model year is not negative, except as allowed under Sec. 1036.745 for
NHTSA's fuel efficiency program. Your credit tracking must account for
the limitation on credit life under Sec. 1036.740(d).
* * * * *
(f) * * *
(1) If you notify us by the deadline for submitting the final
report that errors mistakenly decreased your balance of emission
credits, you may correct the errors and recalculate the balance of
emission credits.
* * * * *
0
111. Amend Sec. 1036.740 by:
0
a. Removing and reserving paragraphs (b) and (c); and
0
b. Revising paragraph (d).
The revision reads as follows:
Sec. 1036.740 Restrictions for using emission credits.
* * * * *
(d) Credit life. NOX credits may be used only for five
model years after the year in which they are generated. For example,
credits you generate in model year 2027 may be used to demonstrate
compliance with emission standards only through model year 2032.
* * * * *
0
112. Revise Sec. 1036.745 to read as follows:
Sec. 1036.745 End-of-year credit deficits.
See 49 CFR 535.7 for provisions related to credit deficits for
NHTSA's fuel consumption credits.
0
113. Amend Sec. 1036.750 by revising paragraph (b) to read as follows:
Sec. 1036.750 Consequences for noncompliance.
* * * * *
(b) You may certify your engine family to an FEL above an
applicable standard based on a projection that you will have enough
emission credits to offset the deficit for the engine family.
* * * * *
[[Page 7783]]
0
114. Revise Sec. 1036.755 to read as follows:
Sec. 1036.755 Information provided to the Department of
Transportation.
After receipt of each manufacturer's final report as specified in
Sec. 1036.730 and completion of any verification testing required to
validate the manufacturer's submitted final data, we will issue a
report to the Department of Transportation with CO2 emission
information and will verify the accuracy of each manufacturer's
equivalent fuel consumption data required by NHTSA under 49 CFR 535.8.
We will send a report to DOT for each engine manufacturer based on each
regulatory category and subcategory, including sufficient information
for NHTSA to determine fuel consumption and associated credit values.
See 49 CFR 535.8 to determine if NHTSA deems submission of this
information to EPA to also be a submission to NHTSA.
0
115. Revise and republish Sec. 1036.801 to read as follows:
Sec. 1036.801 Definitions.
The following definitions apply to this part. The definitions apply
to all subparts unless we note otherwise. All undefined terms have the
meaning the Act gives to them. The definitions follow:
Act means the Clean Air Act, as amended, 42 U.S.C. 7401-7671q.
Adjustable parameter has the meaning given in 40 CFR 1068.50.
Advanced technology means technology certified under 40 CFR
86.1819-14(k)(7), Sec. 1036.615, or 40 CFR 1037.615.
Aftertreatment means relating to a catalytic converter, particulate
filter, or any other system, component, or technology mounted
downstream of the exhaust valve (or exhaust port) whose design function
is to decrease emissions in the engine exhaust before it is exhausted
to the environment. Exhaust gas recirculation (EGR) and turbochargers
are not aftertreatment.
Aircraft means any vehicle capable of sustained air travel more
than 100 feet above the ground.
Alcohol-fueled engine means an engine that is designed to run using
an alcohol fuel. For purposes of this definition, alcohol fuels do not
include fuels with a nominal alcohol content below 25 percent by
volume.
Automated manual transmission (AMT) means a transmission that
operates mechanically similar to a manual transmission, except that an
automated clutch actuator controlled by the onboard computer disengages
and engages the drivetrain instead of a human driver. An automated
manual transmission does not include a torque converter or a clutch
pedal controllable by the driver.
Automatic transmission (AT) means a transmission with a torque
converter (or equivalent) that uses computerize or other internal
controls to shift gears in response to a single driver input for
controlling vehicle speed. Note that automatic manual transmissions are
not automatic transmissions because they do not include torque
converters.
Auxiliary emission control device means any element of design that
senses temperature, motive speed, engine speed (r/min), transmission
gear, or any other parameter for the purpose of activating, modulating,
delaying, or deactivating the operation of any part of the emission
control system.
Averaging set has the meaning given in Sec. 1036.740.
Axle ratio or Drive axle ratio (ka) means the dimensionless number
representing the angular speed of the transmission output shaft divided
by the angular speed of the drive axle.
Calibration means the set of specifications and tolerances specific
to a particular design, version, or application of a component or
assembly capable of functionally describing its operation over its
working range.
Carbon-containing fuel has the meaning given in 40 CFR 1065.1001.
Carryover means relating to certification based on emission data
generated from an earlier model year as described in Sec. 1036.235(d).
Certification means relating to the process of obtaining a
certificate of conformity for an engine family that complies with the
emission standards and requirements in this part.
Certified emission level means the highest deteriorated emission
level in an engine family for a given pollutant from the applicable
transient or steady-state testing, rounded to the same number of
decimal places as the applicable standard.
Charge-depleting has the meaning given in 40 CFR 1066.1001.
Charge-sustaining has the meaning given in 40 CFR 1066.1001.
Complete vehicle means a vehicle meeting the definition of complete
vehicle in 40 CFR 1037.801 when it is first sold as a vehicle. For
example, where a vehicle manufacturer sells an incomplete vehicle to a
secondary vehicle manufacturer, the vehicle is not a complete vehicle
under this part, even after its final assembly.
Compression-ignition means relating to a type of reciprocating,
internal-combustion engine that is not a spark-ignition engine. Note
that Sec. 1036.1 also deems gas turbine engines and other engines to
be compression-ignition engines.
Crankcase emissions means airborne substances emitted to the
atmosphere from any part of the engine crankcase's ventilation or
lubrication systems. The crankcase is the housing for the crankshaft
and other related internal parts.
Critical emission-related component has the meaning given in 40 CFR
1068.30.
Defeat device has the meaning given in Sec. 1036.115(h).
Designated Compliance Officer means one of the following:
(1) For engines subject to compression-ignition standards,
Designated Compliance Officer means Director, Diesel Engine Compliance
Center, U.S. Environmental Protection Agency, 2000 Traverwood Drive,
Ann Arbor, MI 48105; [email protected]; www.epa.gov/ve-certification.
(2) For engines subject to spark-ignition standards, Designated
Compliance Officer means Director, Gasoline Engine Compliance Center,
U.S. Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor,
MI 48105; [email protected]; www.epa.gov/ve-certification.
Deteriorated emission level means the emission level that results
from applying the appropriate deterioration factor to the official
emission result of the emission-data engine. Note that where no
deterioration factor applies, references in this part to the
deteriorated emission level mean the official emission result.
Deterioration factor means the relationship between emissions at
the end of useful life (or point of highest emissions if it occurs
before the end of useful life) and emissions at the low-hour/low-
mileage point, expressed in one of the following ways:
(1) For multiplicative deterioration factors, the ratio of
emissions at the end of useful life (or point of highest emissions) to
emissions at the low-hour point.
(2) For additive deterioration factors, the difference between
emissions at the end of useful life (or point of highest emissions) and
emissions at the low-hour point.
Diesel exhaust fluid (DEF) means a liquid reducing agent (other
than the engine fuel) used in conjunction with selective catalytic
reduction to reduce NOX emissions. Diesel exhaust fluid is
generally understood to be an aqueous solution of urea conforming to
the specifications of ISO 22241.
Drive idle means idle operation during which the vehicle operator
[[Page 7784]]
remains in the vehicle cab, as evidenced by engaging the brake or
clutch pedals, or by other indicators we approve.
Dual-fuel means relating to an engine designed for operation on two
different types of fuel but not on a continuous mixture of those fuels
(see Sec. 1036.601(d)). For purposes of this part, such an engine
remains a dual-fuel engine even if it is designed for operation on
three or more different fuels.
Electronic control module (ECM) means an engine's electronic device
that uses data from engine sensors to control engine parameters.
Emergency vehicle means a vehicle that meets one of the following
criteria:
(1) It is an ambulance or a fire truck.
(2) It is a vehicle that we have determined will likely be used in
emergency situations where emission control function or malfunction may
cause a significant risk to human life. For example, we would consider
a truck that is certain to be retrofitted with a slip-on firefighting
module to become an emergency vehicle, even though it was not initially
designed to be a fire truck. Also, a mobile command center that is
unable to manually regenerate its DPF while on duty could be an
emergency vehicle. In making this determination, we may consider any
factor that has an effect on the totality of the actual risk to human
life. For example, we may consider how frequently a vehicle will be
used in emergency situations or how likely it is that the emission
controls will cause a significant risk to human life when the vehicle
is used in emergency situations. We would not consider the truck in the
example above to be an emergency vehicle if there is merely a
possibility (rather than a certainty) that it will be retrofitted with
a slip-on firefighting module.
Emission control system means any device, system, or element of
design that controls or reduces the emissions of regulated pollutants
from an engine.
Emission-data engine means an engine that is tested for
certification. This includes engines tested to establish deterioration
factors.
Emission-related component has the meaning given in 40 CFR part
1068, appendix A.
Emission-related maintenance means maintenance that substantially
affects emissions or is likely to substantially affect emission
deterioration.
Engine configuration means a unique combination of engine hardware
and calibration (related to the emission standards) within an engine
family, which would include hybrid components for engines certified as
hybrid engines and hybrid powertrains. Engines within a single engine
configuration differ only with respect to normal production variability
or factors unrelated to compliance with emission standards.
Engine family has the meaning given in Sec. 1036.230.
Excluded means relating to engines that are not subject to some or
all of the requirements of this part as follows:
(1) An engine that has been determined not to be a heavy-duty
engine is excluded from this part.
(2) Certain heavy-duty engines are excluded from the requirements
of this part under Sec. 1036.5.
(3) Specific regulatory provisions of this part may exclude a
heavy-duty engine generally subject to this part from one or more
specific standards or requirements of this part.
Exempted has the meaning given in 40 CFR 1068.30.
Exhaust gas recirculation means a technology that reduces emissions
by routing exhaust gases that had been exhausted from the combustion
chamber(s) back into the engine to be mixed with incoming air before or
during combustion. The use of valve timing to increase the amount of
residual exhaust gas in the combustion chamber(s) that is mixed with
incoming air before or during combustion is not considered exhaust gas
recirculation for the purposes of this part.
Family certification level (FCL) means a CO2 emission
level declared by the manufacturer that is at or above emission results
for all emission-data engines.
Family emission limit (FEL) means one of the following:
(1) For NOX emissions, family emission limit means a
NOX emission level declared by the manufacturer to serve in
place of an otherwise applicable emission standard under the ABT
program in subpart H of this part. The FEL serves as the emission
standard for the engine family with respect to all required testing.
(2) For NHTSA's fuel efficiency program under 49 CFR part 535,
family emission limit means a fuel consumption level that serves as the
standard that applies for testing individual certified engines. The
CO2 FEL is equal to the CO2 FCL multiplied by
1.03 and rounded to the same number of decimal places as the standard.
Federal Test Procedure (FTP) means the applicable transient duty
cycle described in Sec. 1036.512 designed to measure exhaust emissions
during urban driving.
Final drive ratio (kd) means the dimensionless number representing
the angular speed of the transmission input shaft divided by the
angular speed of the drive axle when the vehicle is operating in its
highest available gear. The final drive ratio is the transmission gear
ratio (in the highest available gear) multiplied by the drive axle
ratio.
Flexible-fuel means relating to an engine designed for operation on
any mixture of two or more different types of fuels (see Sec.
1036.601(d)).
Fuel type means a general category of fuels such as diesel fuel,
gasoline, or natural gas. There can be multiple grades within a single
fuel type, such as premium gasoline, regular gasoline, or gasoline with
10 percent ethanol.
Gear ratio or Transmission gear ratio (kg) means the
dimensionless number representing the angular speed of the
transmission's input shaft divided by the angular speed of the
transmission's output shaft when the transmission is operating in a
specific gear.
Good engineering judgment has the meaning given in 40 CFR 1068.30.
See 40 CFR 1068.5 for the administrative process we use to evaluate
good engineering judgment.
Greenhouse gas Emissions Model (GEM) means the GEM simulation tool
described in 40 CFR 1037.520. Note that an updated version of GEM
applies starting in model year 2021.
Gross vehicle weight rating (GVWR) means the value specified by the
vehicle manufacturer as the maximum design loaded weight of a single
vehicle, consistent with good engineering judgment.
Heavy-duty engine means any engine which the engine manufacturer
could reasonably expect to be used for motive power in a heavy-duty
vehicle. For purposes of this definition in this part, the term
``engine'' includes internal combustion engines and other devices that
convert chemical fuel into motive power. For example, a gas turbine
used in a heavy-duty vehicle is a heavy-duty engine.
Heavy-duty vehicle means any motor vehicle above 8,500 pounds GVWR.
An incomplete vehicle is also a heavy-duty vehicle if it has a curb
weight above 6,000 pounds or a basic vehicle frontal area greater than
45 square feet. Curb weight and basic vehicle frontal area have the
meaning given in 40 CFR 86.1803-01.
Hybrid means relating to an engine or powertrain that includes a
Rechargeable Energy Storage System. Hybrid engines store and recover
energy in a way that is integral to the engine or otherwise upstream of
the vehicle's transmission. Examples of hybrid engines include
[[Page 7785]]
engines with hybrid components connected to the front end of the engine
(P0), connected to the crankshaft before the clutch (P1), or connected
between the clutch and the transmission where the clutch upstream of
the hybrid feature is in addition to the transmission clutch or
clutches (P2). Engine-based systems that recover kinetic energy to
power an electric heater in the aftertreatment are themselves not
sufficient to qualify as a hybrid engine. The provisions in this part
that apply for hybrid powertrains apply equally for hybrid engines,
except as specified. Note that certain provisions in this part treat
hybrid powertrains intended for vehicles that include regenerative
braking different than those intended for vehicles that do not include
regenerative braking. The definition of hybrid includes plug-in hybrid
electric powertrains.
Hydrocarbon (HC) has the meaning given in 40 CFR 1065.1001.
Identification number means a unique specification (for example, a
model number/serial number combination) that allows someone to
distinguish a particular engine from other similar engines.
Incomplete vehicle means a vehicle meeting the definition of
incomplete vehicle in 40 CFR 1037.801 when it is first sold (or
otherwise delivered to another entity) as a vehicle.
Innovative technology means technology certified under Sec.
1036.610 (also described as ``off-cycle technology'').
Liquefied petroleum gas (LPG) means a liquid hydrocarbon fuel that
is stored under pressure and is composed primarily of nonmethane
compounds that are gases at atmospheric conditions. Note that, although
this commercial term includes the word ``petroleum'', LPG is not
considered to be a petroleum fuel under the definitions of this
section.
Low-hour means relating to an engine that has stabilized emissions
and represents the undeteriorated emission level. This would generally
involve less than 300 hours of operation for engines with
NOX aftertreatment and 125 hours of operation for other
engines.
Manual transmission (MT) means a transmission that requires the
driver to shift the gears and manually engage and disengage the clutch.
Manufacture means the physical and engineering process of
designing, constructing, and/or assembling a heavy-duty engine or a
heavy-duty vehicle.
Manufacturer has the meaning given in 40 CFR 1068.30.
Medium-duty passenger vehicle has the meaning given in 40 CFR
86.1803.
Model year means the manufacturer's annual new model production
period, except as restricted under this definition. It must include
January 1 of the calendar year for which the model year is named, may
not begin before January 2 of the previous calendar year, and it must
end by December 31 of the named calendar year. Manufacturers may not
adjust model years to circumvent or delay compliance with emission
standards or to avoid the obligation to certify annually.
Motorcoach means a heavy-duty vehicle designed for carrying 30 or
more passengers over long distances. Such vehicles are characterized by
row seating, rest rooms, and large luggage compartments, and facilities
for stowing carry-on luggage.
Motor vehicle has the meaning given in 40 CFR 85.1703.
Natural gas means a fuel whose primary constituent is methane.
Neat has the meaning given in 40 CFR 1065.1001.
New motor vehicle engine has the meaning given in the Act. This
generally means a motor vehicle engine meeting any of the following:
(1) A motor vehicle engine for which the ultimate purchaser has
never received the equitable or legal title is a new motor vehicle
engine. This kind of engine might commonly be thought of as ``brand
new'' although a new motor vehicle engine may include previously used
parts. Under this definition, the engine is new from the time it is
produced until the ultimate purchaser receives the title or places it
into service, whichever comes first.
(2) An imported motor vehicle engine is a new motor vehicle engine
if it was originally built on or after January 1, 1970.
(3) Any motor vehicle engine installed in a new motor vehicle.
Noncompliant engine means an engine that was originally covered by
a certificate of conformity, but is not in the certified configuration
or otherwise does not comply with the conditions of the certificate.
Nonconforming engine means an engine not covered by a certificate
of conformity that would otherwise be subject to emission standards.
Nonmethane hydrocarbon (NMHC) means the sum of all hydrocarbon
species except methane, as measured according to 40 CFR part 1065.
Nonmethane hydrocarbon equivalent (NMHCE) has the meaning given in
40 CFR 1065.1001.
Nonmethane nonethane hydrocarbon equivalent (NMNEHC) has the
meaning given in 40 CFR 1065.1001.
Off-cycle technology means technology certified under Sec.
1036.610 (also described as ``innovative technology'').
Official emission result means the measured emission rate for an
emission-data engine on a given duty cycle before the application of
any deterioration factor, but after the applicability of any required
regeneration or other adjustment factors.
Owners manual means a document or collection of documents prepared
by the engine or vehicle manufacturer for the owner or operator to
describe appropriate engine maintenance, applicable warranties, and any
other information related to operating or keeping the engine. The
owners manual is typically provided to the ultimate purchaser at the
time of sale. The owners manual may be in paper or electronic format.
Oxides of nitrogen has the meaning given in 40 CFR 1065.1001.
Percent has the meaning given in 40 CFR 1065.1001. Note that this
means percentages identified in this part are assumed to be infinitely
precise without regard to the number of significant figures. For
example, one percent of 1,493 is 14.93.
Placed into service means put into initial use for its intended
purpose, excluding incidental use by the manufacturer or a dealer.
Preliminary approval means approval granted by an authorized EPA
representative prior to submission of an application for certification,
consistent with the provisions of Sec. 1036.210.
Primary intended service class has the meaning given in Sec.
1036.140.
Rechargeable Energy Storage System (RESS) has the meaning given in
40 CFR 1065.1001.
Relating to as used in this section means relating to something in
a specific, direct manner. This expression is used in this section only
to define terms as adjectives and not to broaden the meaning of the
terms.
Revoke has the meaning given in 40 CFR 1068.30.
Round has the meaning given in 40 CFR 1065.1001.
Sample means the collection of engines selected from the population
of an engine family for emission testing. This may include testing for
certification, production-line testing, or in-use testing.
Scheduled maintenance means adjusting, removing, disassembling,
cleaning, or replacing components or systems periodically to keep a
part or
[[Page 7786]]
system from failing, malfunctioning, or wearing prematurely.
Small manufacturer means a manufacturer meeting the criteria
specified in 13 CFR 121.201. The employee and revenue limits apply to
the total number of employees and total revenue together for all
affiliated companies (as defined in 40 CFR 1068.30). Note that
manufacturers with low production volumes may or may not be ``small
manufacturers''.
Spark-ignition means relating to a gasoline-fueled engine or any
other type of engine with a spark plug (or other sparking device) and
with operating characteristics significantly similar to the theoretical
Otto combustion cycle. Spark-ignition engines usually use a throttle to
regulate intake air flow to control power during normal operation.
Stop-start means a vehicle technology that automatically turns the
engine off when the vehicle is stopped.
Steady-state has the meaning given in 40 CFR 1065.1001. This
includes idle testing where engine speed and load are held at a finite
set of nominally constant values.
Suspend has the meaning given in 40 CFR 1068.30.
Test engine means an engine in a sample.
Tractor means a vehicle meeting the definition of ``tractor'' in 40
CFR 1037.801, but not classified as a ``vocational tractor'' under 40
CFR 1037.630, or relating to such a vehicle.
Ultimate purchaser means, with respect to any new engine or
vehicle, the first person who in good faith purchases such new engine
or vehicle for purposes other than resale.
United States has the meaning given in 40 CFR 1068.30.
Upcoming model year means for an engine family the model year after
the one currently in production.
U.S.-directed production volume means the number of engines,
subject to the requirements of this part, produced by a manufacturer
for which the manufacturer has a reasonable assurance that sale was or
will be made to ultimate purchasers in the United States.
Vehicle has the meaning given in 40 CFR 1037.801.
Vocational vehicle means a vehicle meeting the definition of
``vocational'' vehicle in 40 CFR 1037.801.
Void has the meaning given in 40 CFR 1068.30.
We (us, our) means the Administrator of the Environmental
Protection Agency and any authorized representatives for issues related
to criteria pollutant standards. In the case of testing, compliance,
and approvals related to fuel consumption standards, ``we (us, our)''
includes the Administrator of the National Highway Traffic Safety
Administration (NHTSA) and any authorized representatives.
Sec. 1036.805 [Amended]
0
116. Amend Sec. 1036.805 in table 1 to paragraph (a) by removing the
entries for ``CH4'' and ``N2O''.
0
117. Amend Sec. 1036.815 by revising paragraph (b) to read as follows:
Sec. 1036.815 Confidential information.
* * * * *
(b) Emission data or information that is publicly available cannot
be treated as confidential business information as described in 40 CFR
1068.11. Data that vehicle manufacturers need for demonstrating
compliance with standards, including fuel-consumption data as described
in Sec. Sec. 1036.535 and 1036.545, also qualify as emission data for
purposes of confidentiality determinations.
PART 1037--CONTROL OF EMISSIONS FROM NEW HEAVY-DUTY MOTOR VEHICLES
0
118. The authority citation for part 1037 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
0
119. Amend Sec. 1037.1 by adding paragraph (c) to read as follows:
Sec. 1037.1 Applicability.
* * * * *
(c) This part establishes criteria pollutant and evaporative and
refueling standards as described in Sec. 1037.101. This part does not
establish standards for CO2 or other greenhouse gas
emissions, but it includes certification and testing provisions related
to CO2 emissions to support the fuel consumption standards
for heavy-duty vehicles adopted by the Department of Transportation's
National Highway Traffic and Safety Administration (NHTSA) under 49 CFR
part 535.
Sec. 1037.5 [Amended]
0
120. Amend Sec. 1037.5 by removing and reserving paragraphs (c) and
(d).
0
121. Amend Sec. 1037.15 by revising paragraph (a) to read as follows:
Sec. 1037.15 Do any other regulation parts apply to me?
(a) Parts 1065 and 1066 of this chapter describe procedures and
equipment specifications for testing engines and vehicles to measure
exhaust emissions. Subpart F of this part 1037 describes how to apply
the testing provisions of 40 CFR parts 1065 and 1066.
* * * * *
Sec. 1037.101 [Amended]
0
122. Amend Sec. 1037.101 by removing and reserving paragraphs (a)(2)
and (b)(2).
0
123. Amend Sec. 1037.102 by revising the section heading and adding
paragraph (c) to read as follows:
Sec. 1037.102 Criteria pollutant exhaust emission standards--NOX, HC,
PM, and CO.
* * * * *
(c) Starting in model year 2024, auxiliary power units installed on
new tractors, including tractors that are glider vehicles or tractors
with no installed propulsion engine, must be certified to the PM
emission standard specified in 40 CFR 1039.699. For model years 2021
through 2023, the APU engine must be certified under 40 CFR part 1039
with a deteriorated emission level for PM at or below 0.15 g/kW-hr.
Selling, offering for sale, or introducing or delivering into commerce
in the United States or importing into the United States a new tractor
subject to this standard is a violation of 40 CFR 1068.101(a)(1) unless
the auxiliary power unit has a valid certificate of conformity and the
required label showing that it meets the PM standard specified in 40
CFR 1039.699 as described in this paragraph (c).
Sec. Sec. 1037.105 and 1037.106 [Removed]
0
124. Remove Sec. Sec. 1037.105 and 1037.106.
Sec. 1037.115 [Amended]
0
125. Amend Sec. 1037.115 by removing paragraphs (e) and (f).
0
126. Revise and republish Sec. 1037.120 to read as follows:
Sec. 1037.120 Emission-related warranty requirements.
(a) General requirements. You must warrant to the ultimate
purchaser and each subsequent purchaser that each new vehicle,
including all parts of its emission control system, meets two
conditions:
(1) It is designed, built, and equipped so it conforms at the time
of sale to the ultimate purchaser with the requirements of this part.
(2) It is free from defects in materials and workmanship that cause
the vehicle to fail to conform to the requirements of this part during
the applicable warranty period.
(b) Warranty period. (1) Your emission-related warranty must be
valid for at least:
(i) 5 years or 50,000 miles for Light HDV.
(ii) 5 years or 100,000 miles for heavy-duty vehicles above 19,500
pounds GVWR.
[[Page 7787]]
(2) You may offer an emission-related warranty more generous than
we require. The emission-related warranty for the vehicle may not be
shorter than any basic mechanical warranty you provide to that owner
without charge for the vehicle. Similarly, the emission-related
warranty for any component may not be shorter than any warranty you
provide to that owner without charge for that component. This means
that your warranty for a given vehicle may not treat emission-related
and nonemission-related defects differently for any component. The
warranty period begins when the vehicle is placed into service.
(c) Components covered. The emission-related warranty covers fuel
cell stacks, RESS, and other components used with battery electric
vehicles and fuel cell electric vehicles. The emission-related warranty
covers all components whose failure would increase a vehicle's
evaporative and refueling emissions (for vehicles subject to
evaporative and refueling emission standards). The emission-related
warranty covers components that are part of your certified
configuration even if another company produces the component.
(d) Limited applicability. You may deny warranty claims under this
section if the operator caused the problem through improper maintenance
or use, as described in 40 CFR 1068.115.
(e) Owners manual. Describe in the owners manual the emission-
related warranty provisions from this section that apply to the
vehicle.
0
127. Revise Sec. 1037.125 to read as follows:
Sec. 1037.125 Maintenance instructions and allowable maintenance.
Give the ultimate purchaser of each new vehicle written
instructions for properly maintaining and using the emission control
system.
Sec. 1037.135 [Amended]
0
128. Amend Sec. 1037.135 by removing and reserving paragraphs (c)(6)
and (7).
0
129. Amend Sec. 1037.140 by revising paragraphs (g) introductory text
and (g)(6) and (7) to read as follows:
Sec. 1037.140 Classifying vehicles and determining vehicle
parameters.
* * * * *
(g) The provisions of this part relating to NHTSA's fuel efficiency
program under 49 CFR part 535 apply to specific vehicle service classes
as follows:
* * * * *
(6) In certain circumstances, you may certify vehicles to standards
that apply for a different vehicle service class. If you optionally
certify vehicles to different standards, those vehicles are subject to
all the regulatory requirements as if the standards were mandatory.
(7) Custom chassis vehicles are subject to the following vehicle
service classes instead of the other provisions in this section:
(i) School buses and motor homes are considered ``Medium HDV''.
(ii) All other custom-chassis are considered ``Heavy HDV''.
* * * * *
0
130. Revise and republish Sec. 1037.150 to read as follows:
Sec. 1037.150 Interim provisions.
The provisions in this section apply instead of other provisions in
this part.
(a) Incentives for early introduction. The provisions of this
paragraph (a) apply with respect to vehicles produced in model years
before 2014. Manufacturers may voluntarily certify in model year 2013
(or earlier model years for electric vehicles) to the fuel consumption
standards of 49 CFR part 535.
(1) This paragraph (a)(1) applies for regulatory subcategories
subject to the standards of 49 CFR part 535. Except as specified in
paragraph (a)(3) of this section, to generate early credits under this
paragraph (a)(1) for any vehicles other than electric vehicles, you
must certify your entire U.S.-directed production volume within the
regulatory subcategory to the standards of 49 CFR part 535. Except as
specified in paragraph (a)(4) of this section, if some vehicle families
within a regulatory subcategory are certified after the start of the
model year, you may generate credits only for production that occurs
after all families are certified. For example, if you produce three
vehicle families in an averaging set and you receive your certificates
for those families on January 4, 2013, March 15, 2013, and April 24,
2013, you may not generate credits for model year 2013 production in
any of the families that occurs before April 24, 2013. Calculate
credits relative to the standard that would apply in model year 2014
using the equations in subpart H of this part. You may bank credits
equal to the surplus credits you generate under this paragraph (a)
multiplied by 1.50. For example, if you have 1.0 Mg of surplus credits
for model year 2013, you may bank 1.5 Mg of credits. Credit deficits
for an averaging set prior to model year 2014 do not carry over to
model year 2014. These credits may be used to show compliance with the
standards of this part for 2014 and later model years. We recommend
that you notify us of your intent to use this paragraph (a)(1) before
submitting your applications.
(2) [Reserved]
(3) You may generate credits for the number of additional SmartWay
designated tractors (relative to your 2012 production), provided you do
not generate credits for those vehicles under paragraph (a)(1) of this
section. Calculate credits for each regulatory subcategory relative to
the standard that would apply in model year 2014 using the equations in
subpart H of this part. Use a production volume equal to the number of
designated model year 2013 SmartWay tractors minus the number of
designated model year 2012 SmartWay tractors. You may bank credits
equal to the surplus credits you generate under this paragraph (a)(3)
multiplied by 1.50. Your 2012 and 2013 model years must be equivalent
in length.
(4) This paragraph (a)(4) applies where you do not receive your
final certificate in a regulatory subcategory within 30 days of
submitting your final application for that subcategory. Calculate your
credits for all production that occurs 30 days or more after you submit
your final application for the subcategory.
(b) Phase 1 coastdown procedures. For tractors subject to Phase 1
standards, the default method for measuring drag area (CdA)
is the coastdown procedure specified in 40 CFR part 1066, subpart D.
This includes preparing the tractor and the standard trailer with
wheels meeting specifications of Sec. 1037.528(b) and submitting
information related to your coastdown testing under Sec. 1037.528(h).
(c) Small manufacturers. The following provisions apply for
qualifying small manufacturers:
(1) The fuel consumption standards under 49 CFR part 535 are
optional for small manufacturers producing vehicles with a date of
manufacture before January 1, 2022. In addition, small manufacturers
producing vehicles that run on any fuel other than gasoline, E85, or
diesel fuel may delay complying with every later standard under this
part by one model year.
(2) Qualifying manufacturers must notify the Designated Compliance
Officer each model year before introducing excluded vehicles into U.S.
commerce. This notification must include a description of the
manufacturer's qualification as a small business under 13 CFR 121.201.
(3) Small manufacturers may meet Phase 1 standards instead of Phase
2 standards in the first year Phase 2 standards apply to them if they
voluntarily comply with the Phase 1 standards for the full preceding
year.
[[Page 7788]]
Specifically, small manufacturers may certify their model year 2022
vehicles to the Phase 1 fuel consumption standards under 49 CFR part
535 if they certify all the vehicles from their annual production
volume included in emission credit calculations for the Phase 1
standards starting on or before January 1, 2021.
(4) See paragraphs (r), (t), (u), and (w) of this section for
additional allowances for small manufacturers.
(d)-(f) [Reserved]
(g) Compliance date. Compliance with the standards of this part was
optional prior to January 1, 2014. This means that if your 2014 model
year begins before January 1, 2014, you may certify for a partial model
year that begins on January 1, 2014, and ends on the day your model
year would normally end.
(h) Off-road vehicle exemption. (1) Vocational vehicles with a date
of manufacture before January 1, 2021, automatically qualify for an
exemption under Sec. 1037.631 if the tires installed on the vehicle
have a maximum speed rating at or below 55 miles per hour.
(2) In unusual circumstances, vehicle manufacturers may ask us to
exempt vehicles under Sec. 1037.631 based on other criteria that are
equivalent to those specified in Sec. 1037.631(a); however, we will
normally not grant relief in cases where the vehicle manufacturer has
credits or can otherwise comply with applicable standards. Request
approval for an exemption under this paragraph (h) before you produce
the subject vehicles.
(i) Limited carryover from Phase 1 to Phase 2. The provisions for
carryover data in Sec. 1037.235(d) do not allow you to use aerodynamic
test results from Phase 1 to support a compliance demonstration for
Phase 2 certification.
(j) Limited prohibition related to early model year engines. The
provisions of this paragraph (j) apply only for vehicles that have a
date of manufacture before January 1, 2018. See Sec. 1037.635 for
related provisions that apply in later model years. The prohibition in
Sec. 1037.601 against introducing into U.S. commerce a vehicle
containing an engine not certified to the standards applicable for the
calendar year of installation does not apply for vehicles using model
year 2014 or 2015 spark-ignition engines, or any model year 2013 or
earlier engines.
(k) Verifying drag areas from in-use tractors. This paragraph (k)
applies for tractors instead of Sec. 1037.401(b) through model year
2020. We may measure the drag area of your vehicles after they have
been placed into service. To account for measurement variability, your
vehicle is deemed to conform to the regulations of this part with
respect to aerodynamic performance if we measure its drag area to be at
or below the maximum drag area allowed for the bin above the bin to
which you certified (for example, Bin II if you certified the vehicle
to Bin III), unless we determine that you knowingly produced the
vehicle to have a higher drag area than is allowed for the bin to which
it was certified.
(l) [Reserved]
(m) Loose engine sales. Manufacturers may certify certain spark-
ignition engines along with chassis-certified heavy-duty vehicles where
they are identical to engines used in those vehicles as described in 40
CFR 86.1819-14(k)(8). Vehicles in which those engines are installed are
subject to standards under 49 CFR part 535.
(n) Transition to engine-based model years. The following
provisions apply for production and ABT reports during the transition
to engine-based model year determinations for vehicles in 2020 and
2021:
(1) If you install model year 2020 or earlier engines in your
vehicles in calendar year 2020, include all those Phase 1 vehicles in
your production and ABT reports related to model year 2020 compliance,
although we may require you identify these separately from vehicles
produced in calendar year 2019.
(2) If you install model year 2020 engines in your vehicles in
calendar year 2021, submit production and ABT reports for those Phase 1
vehicles separate from the reports you submit for Phase 2 vehicles with
model year 2021 engines.
(o)-(p) [Reserved]
(q) Vehicle families for advanced and off-cycle technologies. Apply
the following provisions for grouping vehicles into families if you use
off-cycle technologies under Sec. 1037.610 or advanced technologies
under Sec. 1037.615:
(1) For Phase 1 vehicles, create separate vehicle families for
vehicles that contain advanced or off-cycle technologies; group those
vehicles together in a vehicle family if they use the same advanced or
off-cycle technologies.
(2) For Phase 2 vehicles, create separate vehicle subfamilies for
vehicles that contain advanced or off-cycle technologies; group those
vehicles together in a vehicle subfamily if they use the same advanced
or off-cycle technologies.
(r) Conversion to mid-roof and high-roof configurations. Secondary
vehicle manufacturers that qualify as small manufacturers may convert
low- and mid-roof tractors to mid- and high-roof configurations without
recertification for the purpose of building a custom sleeper tractor or
converting it to run on natural gas, as follows:
(1) The original low- or mid-roof tractor must be covered by a
valid certificate of conformity.
(2) The modifications may not increase the frontal area of the
tractor beyond the frontal area of the equivalent mid- or high-roof
tractor with the corresponding standard trailer. Note that these
dimensions have a tolerance of 2 inches. Use good
engineering judgment to achieve aerodynamic performance similar to or
better than the certifying manufacturer's corresponding mid- or high-
roof tractor.
(3) [Reserved]
(4) We may require that you submit annual production reports as
described in Sec. 1037.250.
(5) Modifications made under this paragraph (r) do not violate 40
CFR 1068.101(b)(1).
(s) Confirmatory testing for Falt-aero. If we conduct coastdown
testing to verify your Falt-aero value for Phase 2 and later
tractors, we will make our determination using the principles of SEA
testing in Sec. 1037.305. We will not replace your
Falt-aero value if the tractor passes. If your tractor
fails, we will generate a replacement value of Falt-aero
based on at least one CdA value and corresponding effective
yaw angle, ceff, from a minimum of 100 valid runs using the
procedures of Sec. 1037.528(h). Note that we intend to minimize the
differences between our test conditions and those of the manufacturer
by testing at similar times of the year where possible and the same
location where possible and when appropriate.
(t) Glider kits and glider vehicles. (1) Glider vehicles conforming
to the requirements in this paragraph (t)(1) are exempt from the Phase
1 emission standards of this part 1037 prior to January 1, 2021.
Engines in such vehicles (including vehicles produced after January 1,
2021) remain subject to the requirements of 40 CFR part 86 applicable
for the engines' original model year, but not subject to the Phase 1 or
Phase 2 standards of 40 CFR part 1036 unless they were originally
manufactured in model year 2014 or later.
(i) You are eligible for the exemption in this paragraph (t)(1) if
you are a small manufacturer and you sold one or more glider vehicles
in 2014 under the provisions of paragraph (c) of this section. You do
not qualify if you only produced glider vehicles for your own use. You
must notify us of your plans to use this exemption before you
[[Page 7789]]
introduce exempt vehicles into U.S. commerce. In your notification, you
must identify your annual U.S.-directed production volume (and sales,
if different) of such vehicles for calendar years 2010 through 2014.
Vehicles you produce before notifying us are not exempt under this
section.
(ii) In a given calendar year, you may produce up to 300 exempt
vehicles under this section, or up to the highest annual production
volume you identify in this paragraph (t)(1), whichever is less.
(iii) Identify the number of exempt vehicles you produced under
this exemption for the preceding calendar year in your annual report
under Sec. 1037.250.
(iv) Include the appropriate statement on the label required under
Sec. 1037.135, as follows:
(A) For Phase 1 vehicles, ``THIS VEHICLE AND ITS ENGINE ARE EXEMPT
UNDER 40 CFR 1037.150(t)(1).''
(B) For Phase 2 vehicles, ``THE ENGINE IN THIS VEHICLE IS EXEMPT
UNDER 40 CFR 1037.150(t)(1).''
(v) If you produce your glider vehicle by installing remanufactured
or previously used components in a glider kit produced by another
manufacturer, you must provide the following to the glider kit
manufacturer prior to obtaining the glider kit:
(A) Your name, the name of your company, and contact information.
(B) A signed statement that you are a qualifying small manufacturer
and that your production will not exceed the production limits of this
paragraph (t)(1). This statement is deemed to be a submission to EPA,
and we may require the glider kit manufacturer to provide a copy to us
at any time.
(vi) The exemption in this paragraph (t)(1) is valid for a given
vehicle and engine only if you meet all the requirements and conditions
of this paragraph (t)(1) that apply with respect to that vehicle and
engine. Introducing such a vehicle into U.S. commerce without meeting
all applicable requirements and conditions violates 40 CFR
1068.101(a)(1).
(vii) Companies that are not small manufacturers may sell
uncertified incomplete vehicles without engines to small manufacturers
for the purpose of producing exempt vehicles under this paragraph
(t)(1), subject to the provisions of Sec. 1037.622. However, such
companies must take reasonable steps to ensure that their incomplete
vehicles will be used in conformance with the requirements of this
part.
(2) Glider vehicles produced using engines certified to model year
2010 or later standards for all pollutants are subject to the same
provisions that apply to vehicles using engines within their useful
life in Sec. 1037.635.
(3) For calendar year 2017, you may produce a limited number of
glider kits and/or glider vehicles subject to the requirements
applicable to model year 2016 glider vehicles, instead of the
requirements of Sec. 1037.635. The limit applies to your combined 2017
production of glider kits and glider vehicles and is equal to your
highest annual production of glider kits and glider vehicles for any
year from 2010 to 2014. Any glider kits or glider vehicles produced
beyond this cap are subject to the provisions of Sec. 1037.635. Count
any glider kits and glider vehicles you produce under paragraph (t)(1)
of this section as part of your production with respect to this
paragraph (t)(3).
(u) Transition to Phase 2 standards. The following provisions allow
for enhanced generation and use of emission credits from Phase 1
vehicles for meeting the Phase 2 standards:
(1) For vocational Light HDV and vocational Medium HDV, credits you
generate in model years 2018 through 2021 may be used through model
year 2027, instead of being limited to a five-year credit life as
specified in Sec. 1037.740(c). For Class 8 vocational vehicles with
Medium HDE, we will approve your request to generate these credits in
and use these credits for the Medium HDV averaging set if you show that
these vehicles would qualify as Medium HDV under the Phase 2 program as
described in Sec. 1037.140(g)(4).
(2) You may use the off-cycle provisions of Sec. 1037.610 to apply
technologies to Phase 1 vehicles as follows:
(i) You may apply an improvement factor of 0.988 for vehicles with
automatic tire inflation systems on all axles.
(ii) For vocational vehicles with automatic engine shutdown systems
that conform with Sec. 1037.660, you may apply an improvement factor
of 0.95.
(iii) For vocational vehicles with stop-start systems that conform
with Sec. 1037.660, you may apply an improvement factor of 0.92.
(iv) For vocational vehicles with neutral-idle systems conforming
with Sec. 1037.660, you may apply an improvement factor of 0.98. You
may adjust this improvement factor if we approve a partial reduction
under Sec. 1037.660(a)(2); for example, if your design reduces fuel
consumption by half as much as shifting to neutral, you may apply an
improvement factor of 0.99.
(3) Small manufacturers may generate credits for natural gas-fueled
vocational vehicles as follows:
(i) Small manufacturers may certify their vehicles instead of
relying on the exemption of paragraph (c) of this section. The
provisions of this part apply for such vehicles, except as specified in
this paragraph (u)(3).
(ii) Use GEM version 2.0.1 to determine a fuel consumption level
for your vehicle, then multiply this value by the engine's Family
Certification Level for CO2 and divide by the engine's
applicable fuel consumption standard.
(4) Phase 1 vocational vehicle credits that small manufacturers
generate may be used through model year 2027.
(v) [Reserved]
(w) Custom-chassis standards for small manufacturers. The following
provisions apply uniquely to qualifying small manufacturers under the
custom-chassis standards of Sec. 1037.105(h):
(1) You may use emission credits generated under Sec. 1037.105(d),
including banked or traded credits from any averaging set. Such credits
remain subject to other limitations that apply under subpart H of this
part.
(2) You may produce up to 200 drayage tractors in a given model
year to the standards described in Sec. 1037.105(h) for ``other
buses''. The limit in this paragraph (w)(2) applies with respect to
vehicles produced by you and your affiliated companies. Treat these
drayage tractors as being in their own averaging set.
(x) Transition to updated GEM. (1) Vehicle manufacturers may
demonstrate compliance with Phase 2 greenhouse gas standards in model
years 2021 through 2023 using GEM Phase 2, Version 3.0, Version 3.5.1,
or Version 4.0 (all incorporated by reference, see Sec. 1037.810).
Manufacturers may change to a different version of GEM for model years
2022 and 2023 for a given vehicle family after initially submitting an
application for certification; such a change must be documented as an
amendment under Sec. 1037.225. Manufacturers may submit an end-of-year
report for model year 2021 using any of the three regulatory versions
of GEM, but only for demonstrating compliance with the custom-chassis
standards in Sec. 1037.105(h); such a change must be documented in the
report submitted under Sec. 1037.730. Once a manufacturer certifies a
vehicle family based on GEM Version 4.0, it may not revert back to
using GEM Phase 2, Version 3.0 or Version 3.5.1 for that vehicle family
in any model year.
(2) Vehicle manufacturers may certify for model years 2021 through
2023 based on fuel maps from engines or
[[Page 7790]]
powertrains that were created using GEM Phase 2, Version 3.0, Version
3.5.1, or Version 4.0 (all incorporated by reference, see Sec.
1037.810). Vehicle manufacturers may alternatively certify in those
years based on fuel maps from powertrains that were created using GEM
Phase 2, Version 3.0, GEM HIL model 3.8, or GEM Phase 2, Version 4.0
(all incorporated by reference, see Sec. 1037.810). Vehicle
manufacturers may continue to certify vehicles in later model years
using fuel maps generated with earlier versions of GEM for model year
2024 and later vehicle families that qualify for using carryover
provisions in Sec. 1037.235(d).
(y) [Reserved]
(z) Constraints for vocational regulatory subcategories. The
following provisions apply to determinations of vocational regulatory
subcategories as described in Sec. 1037.140:
(1) Select the Regional regulatory subcategory for coach buses and
motor homes.
(2) You may not select the Urban regulatory subcategory for any
vehicle with a manual or single-clutch automated manual transmission.
(3) Starting in model year 2024, you must select the Regional
regulatory subcategory for any vehicle with a manual transmission.
(4) You may select the Multi-purpose regulatory subcategory for any
vocational vehicle, except as specified in paragraph (v)(1) of this
section.
(5) You may select the Urban regulatory subcategory for a hybrid
vehicle equipped with regenerative braking, unless it is equipped with
a manual transmission.
(6) You may select the Urban regulatory subcategory for any vehicle
with a hydrokinetic torque converter paired with an automatic
transmission, or a continuously variable automatic transmission, or a
dual-clutch transmission with no more than two consecutive forward
gears between which it is normal for both clutches to be momentarily
disengaged.
(aa) Warranty for components used with battery electric vehicles
and fuel cell electric vehicles. The emission-related warranty
requirements in Sec. 1037.120 are optional for fuel cell stacks, RESS,
and other components used with battery electric vehicles and fuel cell
electric vehicles before model year 2027.
0
131. Amend Sec. 1037.201 by revising paragraph (i) to read as follows:
Sec. 1037.201 General requirements for obtaining a certificate of
conformity.
* * * * *
(i) Vehicles and installed engines must meet exhaust, evaporative,
and refueling emission standards and certification requirements as
described in Sec. Sec. 1037.102 and 1037.103, as applicable. Include
the information described in 40 CFR part 86, subpart S, or 40 CFR
1036.205 in your application for certification in addition to what we
specify in Sec. 1037.205 so we can issue a single certificate of
conformity for all the requirements that apply for your vehicle and the
installed engine.
0
132. Amend Sec. 1037.205 by:
0
a. Revising paragraph (b) introductory text and (b)(8);
0
b. Removing and reserving paragraphs (c) and (q); and
0
c. Revising paragraph (t).
The revisions read as follows:
Sec. 1037.205 What must I include in my application?
* * * * *
(b) Explain how the emission control system operates. As
applicable, describe in detail all system components for controlling
emissions, including all auxiliary emission control devices (AECDs) and
all fuel-system components you will install on any production vehicle.
For any vehicle using RESS (such as fuel cell electric vehicles and
battery electric vehicles), describe in detail all components needed to
charge the system, store energy, and transmit power to move the
vehicle. Identify the part number of each component you describe. For
this paragraph (b), treat as separate AECDs any devices that modulate
or activate differently from each other. Also describe your modeling
inputs as described in Sec. 1037.520, with the following additional
information if it applies for your vehicles:
* * * * *
(8) If you install auxiliary power units in tractors under Sec.
1037.102(c), identify the family name associated with the engine's
certification under 40 CFR part 1039. Starting in model year 2024, also
identify the family name associated with the auxiliary power unit's
certification to the standards of 40 CFR 1039.699.
* * * * *
(t) Include the information required by other subparts of this
part.
* * * * *
0
133. Amend Sec. 1037.230 by revising paragraphs (a) introductory text,
(b), and (d)(2) introductory text to read as follows:
Sec. 1037.230 Vehicle families, sub-families, and configurations.
(a) Divide your product line into families of vehicles based on
regulatory subcategories as specified in this section. Subcategories
are specified using terms defined in Sec. 1037.801. Your vehicle
family is limited to a single model year.
* * * * *
(b) If the vehicles in your family are being certified to more than
one FEL, subdivide your vehicle families into subfamilies that include
vehicles with identical FELs. Note that you may add subfamilies at any
time during the model year.
* * * * *
(d) * * *
(2) For a Phase 2 or later vehicle model that includes a range of
GVWR values that straddle weight classes, you may include all the
vehicles in the same vehicle family if you certify the vehicle family
to the numerically lower fuel consumption standard from the affected
service classes. Vehicles that are optionally certified to a more
stringent standard under this paragraph (d)(2) are subject to useful-
life and all other provisions corresponding to the weight class with
the numerically lower fuel consumption standard. For a Phase 2 or later
tractor model that includes a range of roof heights that straddle
subcategories, you may include all the vehicles in the same vehicle
family if you certify the vehicle family to the appropriate subcategory
as follows:
* * * * *
0
134. Revise Sec. 1037.231 to read as follows:
Sec. 1037.231 Powertrain families.
See 40 CFR 1036.231 for provisions describing how to divide your
product line into powertrain families.
0
135. Amend Sec. 1037.235 by revising the introductory text to read as
follows:
Sec. 1037.235 Testing requirements for certification.
This section describes the emission testing you must perform to
show compliance with NHTSA's fuel efficiency program under 49 CFR part
535, and to determine any input values from Sec. 1037.520 that involve
measured quantities.
* * * * *
0
136. Revise Sec. 1037.241 to read as follows:
Sec. 1037.241 Demonstrating compliance with fuel consumption
standards.
(a) Compliance determinations for purposes of certification depend
on whether or not you participate in the ABT program in subpart H of
this part.
(1) If none of your vehicle families generate or use credits in a
given model year, each of your vehicle families is
[[Page 7791]]
considered in compliance if all vehicle configurations in the family
have modeled CO2 emission rates from Sec. 1037.520 that are
at or below the applicable standards. A vehicle family is deemed not to
comply if any vehicle configuration in the family has a modeled fuel
consumption value that is above the applicable standard.
(2) If you generate or use credits with one or more vehicle
families in a given model year, your vehicle families within an
averaging set are considered in compliance if the sum of positive and
negative credits for all vehicle configurations in those vehicle
families lead to a zero balance or a positive balance of credits,
except as allowed by Sec. 1037.745 for NHTSA's fuel efficiency
program. Note that the FEL is considered to be the applicable emission
standard for an individual configuration.
(b) We may require you to provide an engineering analysis showing
that the performance of your controls will not deteriorate during the
useful life with proper maintenance. If we determine that your controls
are likely to deteriorate during the useful life, we may require you to
develop and apply deterioration factors consistent with good
engineering judgment. Where the highest useful life fuel consumption
occurs between the end of useful life and at the low-hour test point,
base deterioration factors for the vehicles on the difference between
(or ratio of) the point at which the highest fuel consumption occurs
and the low-hour test point.
0
137. Amend Sec. 1037.501 by revising the introductory text and
paragraphs (a), (b), (d)(2), and (f) to read as follows:
Sec. 1037.501 General testing and modeling provisions.
This subpart specifies how to perform testing and modeling required
elsewhere in this part for demonstrating compliance with fuel
consumption standards under 49 CFR part 535.
(a) Except as specified in subpart B of this part, you must
demonstrate that you meet the applicable standards using modeling as
described in Sec. 1037.520. This modeling depends on several measured
values as described in this subpart. You may use fuel-mapping
information from the engine manufacturer as described in 40 CFR
1036.535 and 1036.540, or you may use powertrain testing as described
in 40 CFR 1036.545.
(b) Where testing is required, use equipment and procedures as
described in 40 CFR part 1065 and part 1066. Measure CO2
emissions as specified in 40 CFR part 1065 and part 1066. Use the
applicable duty cycles specified in Sec. 1037.510.
* * * * *
(d) * * *
(2) For diesel-fueled vehicles, use the appropriate diesel fuel
specified for emission testing. Unless specified otherwise, the
appropriate diesel test fuel is ultra-low sulfur diesel fuel.
* * * * *
(f) This subpart is addressed to you as a manufacturer, but it
applies equally to anyone who does testing for you, and to us when we
perform testing to determine if your vehicles meet the standards.
* * * * *
0
138. Amend Sec. 1037.520 by revising the section heading and
introductory text to read as follows:
Sec. 1037.520 Modeling CO2 emissions to show that vehicles comply
with fuel consumption standards.
This section describes how to use the Greenhouse gas Emissions
Model (GEM) to show compliance with NHTSA's fuel consumption standards
under 49 CFR part 535. Use GEM version 2.0.1 to demonstrate compliance
with Phase 1 standards; use GEM Phase 2, Version 4.0 to demonstrate
compliance with Phase 2 standards (both incorporated by reference, see
Sec. 1037.810). Use good engineering judgment when demonstrating
compliance using GEM.
* * * * *
0
139. Amend Sec. 1037.540 by revising the introductory text and
paragraph (a)(1) to read as follows:
Sec. 1037.540 Special procedures for testing vehicles with hybrid
power take-off.
This section describes optional procedures for quantifying the
reduction in fuel consumption for vehicles as a result of running power
take-off (PTO) devices with a hybrid energy delivery system. See 40 CFR
1036.545 for powertrain testing requirements that apply for drivetrain
hybrid systems. The procedures are written to test the PTO by ensuring
that the engine produces all of the energy with no net change in stored
energy (charge-sustaining), and for plug-in hybrid electric vehicles,
also allowing for drawing down the stored energy (charge-depleting).
The full charge-sustaining test for the hybrid vehicle is from a fully
charged rechargeable energy storage system (RESS) to a depleted RESS
and then back to a fully charged RESS. You must include all hardware
for the PTO system. You may ask us to modify the provisions of this
section to allow testing hybrid vehicles that use a technology other
than batteries for storing energy, consistent with good engineering
judgment. For plug-in hybrid electric vehicles, use a utility factor to
properly weight charge-sustaining and charge-depleting operation as
described in paragraph (f)(3) of this section.
(a) * * *
(1) Select a vehicle with a hybrid energy delivery system to
represent the range of PTO configurations that will be covered by the
test data. If your test data will represent more than one PTO
configuration, use good engineering judgment to select the
configuration with the maximum number of PTO circuits that has the
smallest potential reduction in fuel consumption.
* * * * *
0
140. Add Sec. 1037.550 to subpart F to read as follows:
Sec. 1037.550 Powertrain testing.
See 40 CFR 1036.545 for the powertrain test procedure.
0
141. Amend Sec. 1037.551 by revising paragraph (a) to read as follows:
Sec. 1037.551 Engine-based simulation of powertrain testing.
* * * * *
(a) Use the procedures of 40 CFR part 1065 to set up the engine,
measure emissions, and record data. Measure individual parameters and
emission constituents as described in this section. For hybrid
powertrains, correct for the net energy change of the energy storage
device as described in 40 CFR 1066.501(a)(3).
* * * * *
0
142. Amend Sec. 1037.555 by revising paragraph (c) to read as follows:
Sec. 1037.555 Special procedures for testing Phase 1 hybrid systems.
* * * * *
(c) Collect and measure emissions as described in 40 CFR part 1066.
Calculate emission rates in grams per ton-mile without rounding.
Determine values for A, B, C, and M for the vehicle being simulated as
specified in 40 CFR part 1066. If you will apply an improvement factor
or test results to multiple vehicle configurations, use values of A, B,
C, M, ka, and r that represent the vehicle configuration
with the smallest potential reduction in greenhouse gas emissions as a
result of the hybrid capability.
* * * * *
0
143. Amend Sec. 1037.560 by revising paragraph (b)(4) to read as
follows:
Sec. 1037.560 Axle efficiency test.
* * * * *
(b) * * *
[[Page 7792]]
(4) Add gear oil according to the axle manufacturer's instructions.
If the axle manufacturer specifies multiple gear oils, select the one
with the highest viscosity at operating temperature. You may use a
lower-viscosity gear oil if we approve it. Fill the gear oil to a level
that represents in-use operation. You may use an external gear oil
conditioning system, as long as it does not affect measured values.
* * * * *
0
144. Amend Sec. 1037.565 by revising paragraph (b)(3) to read as
follows:
Sec. 1037.565 Transmission efficiency test.
* * * * *
(b) * * *
(3) Add transmission oil according to the transmission
manufacturer's instructions. If the transmission manufacturer specifies
multiple transmission oils, select the one with the highest viscosity
at operating temperature. You may use a lower-viscosity transmission
oil if we approve it. Fill the transmission oil to a level that
represents in-use operation. You may use an external transmission oil
conditioning system, as long as it does not affect measured values.
* * * * *
0
145. Amend Sec. 1037.570 by revising paragraph (a)(4)(i) to read as
follows:
Sec. 1037.570 Procedures to characterize torque converters.
* * * * *
(a) * * *
(4) * * *
(i) If the torque converter manufacturer specifies multiple
transmission oils, select the one with the highest viscosity at
operating temperature. You may use a lower-viscosity transmission oil
if we approve it.
* * * * *
0
146. Amend Sec. 1037.605 by revising paragraph (d) to read as follows:
Sec. 1037.605 Installing engines certified to alternate standards for
specialty vehicles.
* * * * *
(d) Vehicle standards. The Vehicle standards apply as follows for
these vehicles:
(1) Vehicles qualifying under this section are subject to
evaporative emission standards as specified in Sec. 1037.103, but are
exempt from the other requirements of this part, except as specified in
this section and in Sec. 1037.601.
(2) Hybrid vehicles may need to use GEM in conjunction with
powertrain testing to demonstrate compliance with fuel consumption
standards.
0
147. Amend Sec. 1037.610 by revising paragraphs (a) and (d)(1) to read
as follows:
Sec. 1037.610 Vehicles with off-cycle technologies.
(a) You may ask us to apply the provisions of this section for fuel
consumption reductions resulting from vehicle technologies that were
not in common use with heavy-duty vehicles before model year 2010 that
are not reflected in GEM. While you are not required to prove that such
technologies were not in common use with heavy-duty vehicles before
model year 2010, we will not approve your request if we determine that
they do not qualify. These may be described as off-cycle or innovative
technologies. You may apply these provisions for fuel consumption
reductions reflected in the specified test procedures if they are not
reflected in GEM, except as allowed under paragraph (g) of this
section. We will apply these provisions only for technologies that will
result in measurable, demonstrable, and verifiable real-world fuel
consumption reductions.
* * * * *
(d) * * *
(1) A detailed description of the off-cycle technology and how it
functions to reduce fuel consumption under conditions not represented
on the duty cycles required for certification.
* * * * *
0
148. Amend Sec. 1037.615 by:
0
a. Revising paragraphs (a), (b)(4), and (d);
0
b. Removing and reserving paragraph (f); and
0
c. Revising paragraph (g).
The revisions read as follows:
Sec. 1037.615 Advanced technologies.
(a) This section describes how to calculate emission credits for
advanced technologies. You may calculate Phase 1 advanced technology
credits through model year 2020 for hybrid vehicles with regenerative
braking, vehicles equipped with Rankine-cycle engines, battery electric
vehicles, and fuel cell electric vehicles. You may calculate Phase 2
advanced technology credits through model year 2026 for plug-in hybrid
electric vehicles, battery electric vehicles, and fuel cell electric
vehicles. You may not generate credits for Phase 1 engine technologies
for which the engines generate CO2 credits under 40 CFR part
1036.
(b) * * *
* * * * *
(d) For Phase 2 plug-in hybrid electric vehicles and for fuel cells
powered by any fuel other than hydrogen, calculate credits using an FEL
based on measurements from powertrain testing. Phase 2 advanced
technology credits do not apply for hybrid vehicles that have no plug-
in capability.
* * * * *
(g) As specified in subpart H of this part, advanced-technology
credits generated from Phase 1 vehicles under this section may be used
under this part outside of the averaging set in which they were
generated. Advanced-technology credits generated from Phase 2 and later
vehicles are subject to the averaging-set restrictions that apply to
other credits.
(h) You may certify using both provisions of this section and the
off-cycle technology provisions of Sec. 1037.610, provided you do not
double count benefits.
0
149. Amend Sec. 1037.620 by revising paragraphs (a)(2) and (e) to read
as follows:
Sec. 1037.620 Responsibilities for multiple manufacturers.
* * * * *
(a) * * *
(2) We will apply the requirements of subparts C and D of this part
to the manufacturer that certifies the vehicle. Other manufacturers are
required to comply with the requirements of subparts C and D of this
part only when notified by us. In our notification, we will specify a
reasonable time period in which you need to comply with the
requirements identified in the notice. See Sec. 1037.601 for the
applicability of 40 CFR part 1068 to these other manufacturers and
remanufacturers.
* * * * *
(e) We may require component manufacturers to provide information
or take other actions. For example, we may require component
manufacturers to test components they produce.
0
150. Amend Sec. 1037.622 by:
0
a. Revising the introductory text and paragraph (a)(2); and
0
b. Removing and reserving paragraph (d)(5).
The revisions read as follows:
Sec. 1037.622 Shipment of partially complete vehicles to secondary
vehicle manufacturers.
This section specifies how manufacturers may introduce partially
complete vehicles into U.S. commerce (or in the case of certain custom
vehicles, introduce complete vehicles into U.S. commerce for
modification by a small manufacturer). The provisions of this section
are intended to accommodate normal business practices without
compromising the effectiveness
[[Page 7793]]
of certified emission controls. You may not use the provisions of this
section to circumvent the intent of this part.
(a) * * *
(2) Uncertified vehicles that will be certified by secondary
vehicle manufacturers. Manufacturers may introduce into U.S. commerce
partially complete vehicles for which they do not hold the required
certificate of conformity only as allowed by paragraph (b) of this
section; however, the requirements of this section do not apply for
tractors or vocational vehicles with a date of manufacture before
January 1, 2022, that are produced by a secondary vehicle manufacturer
if they are excluded under Sec. 1037.5.
* * * * *
0
151. Amend Sec. 1037.631 by revising the introductory text and
paragraph (a) introductory text to read as follows:
Sec. 1037.631 Exemption for vocational vehicles intended for off-road
use.
This section provides an exemption from the fuel consumption
standards under 49 CFR part 535 for certain vocational vehicles
(including certain vocational tractors) that are intended to be used
extensively in off-road environments such as forests, oil fields, and
construction sites. This section does not exempt engines used in
vocational vehicles from the standards of 40 CFR part 86 or part 1036.
Note that you may not include these exempted vehicles in any credit
calculations.
(a) Qualifying criteria. Vocational vehicles intended for off-road
use are exempt without request, subject to the provisions of this
section, if they are primarily designed to perform work off-road (such
as in oil fields, mining, forests, or construction sites), and they
meet at least one of the criteria of paragraph (a)(1) of this section
and at least one of the criteria of paragraph (a)(2) of this section.
See Sec. 1037.105(h) for alternate Phase 2 standards that apply for
vehicles meeting only one of these sets of criteria.
* * * * *
0
152. Amend Sec. 1037.635 by:
0
a. Revising paragraphs (a) and (b) introductory text; and
0
b. Removing and reserving paragraph (b)(1).
The revisions read as follows:
Sec. 1037.635 Glider kits and glider vehicles.
* * * * *
(a) Vehicles produced from glider kits and other glider vehicles
are subject to the same standards as other new vehicles. Note that this
requirement for the vehicle generally applies even if the engine meets
the criteria of paragraph (c)(1) of this section. For engines
originally produced before 2017, if you are unable to obtain a fuel map
for an engine you may ask to use a default map, consistent with good
engineering judgment.
(b) Section 1037.601(a)(1) disallows the introduction into U.S.
commerce of a new vehicle (including a vehicle assembled from a glider
kit) unless it has an engine that is certified to the applicable
standards in 40 CFR parts 86 and 1036. Except as specified otherwise in
this part, the standards apply for engines used in glider vehicles as
follows:
* * * * *
Sec. 1037.645 [Removed]
0
153. Remove Sec. 1037.645.
0
154. Amend Sec. 1037.655 by revising paragraph (a) to read as follows:
Sec. 1037.655 Post-useful life vehicle modifications.
(a) General. This section specifies vehicle modifications that may
occur in certain circumstances after a vehicle reaches the end of its
regulatory useful life. We may require a higher burden of proof with
respect to modifications that occur within the useful life period, and
the specific examples presented here do not necessarily apply within
the useful life. This section also does not apply with respect to
engine modifications or recalibrations.
* * * * *
Sec. Sec. 1037.665 and 1037.670 [Removed]
0
155. Remove Sec. Sec. 1037.665 and 1037.670.
0
156. Revise Sec. 1037.701 to read as follows:
Sec. 1037.701 General provisions.
(a) You may average, bank, and trade credits as described in 49 CFR
part 535. Participation in this program is voluntary.
(b) The definitions of subpart I of this part apply to this subpart
in addition to the following definitions:
(1) Actual credits means credits you have generated that we have
verified by reviewing your final report.
(2) Averaging set means a set of vehicles in which credits may be
exchanged. Note that an averaging set may comprise more than one
regulatory subcategory. See Sec. 1037.740.
(3) Broker means any entity that facilitates a trade of credits
between a buyer and seller.
(4) Buyer means the entity that receives credits as a result of a
trade.
(5) Reserved credits means credits you have generated that we have
not yet verified by reviewing your final report.
(6) Seller means the entity that provides credits during a trade.
(7) Standard means the standard that applies under subpart B of
this part for vehicles not participating in the ABT program of this
subpart.
(8) Trade means to exchange credits, either as a buyer or seller.
(c) Credits may be exchanged only within an averaging set, except
as specified in Sec. 1037.740.
(d) You may not use credits generated under this subpart to offset
any emissions that exceed an FEL or standard.
(e) You may use either of the following approaches to retire or
forego credits:
(1) You may trade credits generated from any number of your
vehicles to the vehicle purchasers or other parties to retire the
credits. Identify any such credits in the reports described in Sec.
1037.730. Vehicles must comply with the applicable FELs even if you
donate or sell the corresponding credits under this paragraph (e).
Those credits may no longer be used by anyone to demonstrate compliance
with any standards.
(2) You may certify a family using an FEL below the standard as
described in this part and choose not to generate credits for that
family. If you do this, you do not need to calculate credits for those
families and you do not need to submit or keep the associated records
described in this subpart for that family.
(f) Credits may be used in the model year they are generated. Where
allowed, surplus credits may be banked for future model years. Surplus
credits may sometimes be used for past model years, as described in
Sec. 1037.745. You may not apply banked or traded credits in a given
model year until you have used all available credits through averaging
to resolve credit balances for that model year.
(g) You may increase or decrease an FEL during the model year by
amending your application for certification under Sec. 1037.225. The
new FEL may apply only to vehicles you have not already introduced into
commerce.
Sec. Sec. 1037.705,1037.710, 1037.715, and 1037.720 [Removed]
0
157. Remove Sec. Sec. 1037.705, 1037.710, 1037.715, and 1037.720.
0
158. Revise Sec. 1037.725 to read as follows:
Sec. 1037.725 Required information for certification.
(a) You must declare your intent to use the provisions of this
subpart for each vehicle family that will be certified using the ABT
program before
[[Page 7794]]
production. You must also declare the FELs you select for the vehicle
family or subfamily for each pollutant for which you are using the ABT
program. Your FELs must comply with the specifications of subpart B of
this part. FELs must be expressed to the same number of decimal places
as the applicable standards.
(b) Your declaration must include the following information:
(1) A statement that, to the best of your belief, you will not have
a negative balance of credits for any averaging set when all credits
are calculated at the end of the year; or a statement that you will
have a negative balance of credits for one or more averaging sets but
that it is allowed under Sec. 1037.745 for NHTSA's fuel efficiency
program.
(2) Calculations of projected credits (positive or negative) based
on projected U.S.-directed production volumes. We may require you to
include similar calculations from your other vehicle families to
project your net credit balances for the model year. If you project
negative credits for a family or subfamily, state the source of
positive credits you expect to use to offset the negative credits.
0
159. Revise and republish Sec. 1037.730 to read as follows:
Sec. 1037.730 ABT reports.
(a) If you certify any vehicle families using the ABT provisions of
this subpart, send us a final report by September 30 following the end
of the model year.
(b) Your report must include the following information for each
vehicle family participating in the ABT program:
(1) Vehicle-family and subfamily designations, and averaging set.
(2) The regulatory subcategory and standards that would otherwise
apply to the vehicle family.
(3) The FEL. If you change the FEL after the start of production,
identify the date that you started using the new FEL and/or give the
vehicle identification number for the first vehicle covered by the new
FEL. In this case, identify each applicable FEL and calculate the
positive or negative credits as specified in Sec. 1037.225.
(4) The projected and actual production volumes for the model year
for calculating credits. If you changed an FEL during the model year,
identify the actual production volume associated with each FEL.
(5) Useful life.
(6) Calculated positive or negative credits for the whole vehicle
family. Identify any credits that you traded, as described in paragraph
(d)(1) of this section.
(7) If you have a negative credit balance for the averaging set in
the given model year, specify whether the vehicle family (or certain
subfamilies with the vehicle family) have a credit deficit for the
year. Consider for example, a manufacturer with three vehicle families
(``A'', ``B'', and ``C'') in a given averaging set. If family A
generates enough credits to offset the negative credits of family B but
not enough to also offset the negative credits of family C (and the
manufacturer has no banked credits in the averaging set), the
manufacturer may designate families A and B as having no deficit for
the model year, provided it designates family C as having a deficit for
the model year.
(c) Your report must include the following additional information:
(1) Show that your net balance of credits from all your
participating vehicle families in each averaging set in the applicable
model year is not negative, except as allowed under Sec. 1037.745 for
NHTSA's fuel efficiency program. Your credit tracking must account for
the limitation on credit life under Sec. 1037.740(c).
(2) State whether you will retain any credits for banking. If you
choose to retire credits that would otherwise be eligible for banking,
identify the families that generated the credits, including the number
of credits from each family.
(3) State that the report's contents are accurate.
(4) Identify the technologies that make up the certified
configuration associated with each vehicle identification number. You
may identify this as a range of identification numbers for vehicles
involving a single, identical certified configuration.
(d) If you trade credits, you must send us a report within 90 days
after the transaction, as follows:
(1) As the seller, you must include the following information in
your report:
(i) The corporate names of the buyer and any brokers.
(ii) A copy of any contracts related to the trade.
(iii) The averaging set corresponding to the vehicle families that
generated credits for the trade, including the number of credits from
each averaging set.
(2) As the buyer, you must include the following information in
your report:
(i) The corporate names of the seller and any brokers.
(ii) A copy of any contracts related to the trade.
(iii) How you intend to use the credits, including the number of
credits you intend to apply for each averaging set.
(e) Send your reports electronically to the Designated Compliance
Officer using an approved information format. If you want to use a
different format, send us a written request with justification for a
waiver.
(f) Correct errors in your report as follows:
(1) If you notify us by the deadline for submitting the final
report that errors mistakenly decreased your balance of credits, you
may correct the errors and recalculate the balance of credits. If you
notify us that errors mistakenly decreased your balance of credits
after the deadline for submitting the final report, you may correct the
errors and recalculate the balance of credits after applying a 10
percent discount to the credit correction, but only if you notify us
within 24 months after the deadline for submitting the final report. If
you report a negative balance of credits, we may disallow corrections
under this paragraph (f)(1).
(2) If you or we determine any time that errors mistakenly
increased your balance of credits, you must correct the errors and
recalculate the balance of credits.
0
160. Amend Sec. 1037.735 by revising paragraphs (b) and (e) to read as
follows:
Sec. 1037.735 Recordkeeping.
* * * * *
(b) Keep the records required by this section for at least eight
years after the due date for the final report. You may not use credits
for any vehicles if you do not keep all the records required under this
section. You must therefore keep these records to continue to bank
valid credits.
* * * * *
(e) We may require you to keep additional records or to send us
relevant information not required by this section.
0
161. Revise Sec. 1037.740 to read as follows:
Sec. 1037.740 Restrictions for using credits.
The following restrictions apply for using credits.
(a) Averaging sets. Credits may be exchanged only within an
averaging set. The following principal averaging sets apply for
vehicles certified to the standards of this part involving credits as
described in this subpart:
(1) Light HDV.
(2) Medium HDV.
(3) Heavy HDV.
(4) Note that other separate averaging sets also apply for credits
not related to
[[Page 7795]]
this part. Separate averaging sets also apply for engines under 40 CFR
part 1036, including engines used in vehicles subject to this subpart.
(b) [Reserved]
(c) Credit life. Banked credits may be used only for five model
years after the year in which they are generated.
(d) Other restrictions. Other sections of this part specify
additional restrictions for using credits under certain special
provisions.
0
162. Revise Sec. 1037.745 to read as follows:
Sec. 1037.745 End-of-year credit deficits.
See 49 CFR 535.7 for provisions related to credit deficits for
NHTSA's fuel consumption credits.
Sec. 1037.750 [Removed]
0
163. Remove Sec. 1037.750.
0
164. Amend Sec. 1037.801 by:
0
a. Revising the definitions of ``Model year'', ``Phase 1'', and ``Phase
2'';
0
b. Removing the definitions of ``Phase 3'' and ``State of certified
energy (SOCE)'';
0
c. Revising the definition of ``Tractor'';
0
d. Removing the definition of ``Usable battery energy (UBE)''; and
0
e. Revising the definitions of ``Vocational vehicle'' and ``We (us,
our)''.
The revisions read as follows:
Sec. 1037.801 Definitions.
* * * * *
Model year means one of the following for compliance with this
part. Note that manufacturers may have other model year designations
for the same vehicle for compliance with other requirements or for
other purposes:
(1) For vehicles with a date of manufacture on or after January 1,
2021, model year means the manufacturer's annual new model production
period based on the vehicle's date of manufacture, where the model year
is the calendar year corresponding to the date of manufacture, except
as follows:
(i) The vehicle's model year may be designated as the year before
the calendar year corresponding to the date of manufacture if the
engine's model year is also from an earlier year. You may ask us to
extend your prior model year certificate to include such vehicles. Note
that Sec. 1037.601(a)(2) limits the extent to which vehicle
manufacturers may install engines built in earlier calendar years.
(ii) The vehicle's model year may be designated as the year after
the calendar year corresponding to the vehicle's date of manufacture.
For example, a manufacturer may produce a new vehicle by installing the
engine in December 2023 and designating it as a model year 2024
vehicle.
(2) For vehicles with a date of manufacture before January 1, 2021,
model year means the manufacturer's annual new model production period,
except as restricted under this definition and 40 CFR part 85, subpart
X. It must include January 1 of the calendar year for which the model
year is named, may not begin before January 2 of the previous calendar
year, and it must end by December 31 of the named calendar year. The
model year may be set to match the calendar year corresponding to the
date of manufacture.
(i) The manufacturer who holds the certificate of conformity for
the vehicle must assign the model year based on the date when its
manufacturing operations are completed relative to its annual model
year period. In unusual circumstances where completion of your assembly
is delayed, we may allow you to assign a model year one year earlier,
provided it does not affect which regulatory requirements will apply.
(ii) Unless a vehicle is being shipped to a secondary vehicle
manufacturer that will hold the certificate of conformity, the model
year must be assigned prior to introduction of the vehicle into U.S.
commerce. The certifying manufacturer must redesignate the model year
if it does not complete its manufacturing operations within the
originally identified model year. A vehicle introduced into U.S.
commerce without a model year is deemed to have a model year equal to
the calendar year of its introduction into U.S. commerce unless the
certifying manufacturer assigns a later date.
* * * * *
Phase 1 means relating to the Phase 1 fuel consumption standards.
Phase 2 means relating to the Phase 2 fuel consumption standards.
* * * * *
Tractor means a truck designed primarily for drawing other motor
vehicles and not so constructed as to carry a load other than a part of
the weight of the vehicle and the load so drawn. This includes most
heavy-duty vehicles specifically designed for the primary purpose of
pulling trailers, but does not include vehicles designed to carry other
loads. For purposes of this definition ``other loads'' would not
include loads carried in the cab, sleeper compartment, or toolboxes.
Examples of vehicles that are similar to tractors but that are not
tractors under this part include dromedary tractors, automobile
haulers, straight trucks with trailers hitches, and tow trucks. Note
that the provisions of this part that apply for tractors do not apply
for tractors that are classified as vocational tractors under Sec.
1037.630.
* * * * *
Vocational vehicle means a heavy-duty vehicle at or below 26,000
pounds GVWR that is not subject to standards under 40 CFR part 86,
subpart S, or a heavy-duty vehicle above 26,000 pounds GVWR that is not
a tractor.
* * * * *
We (us, our) means the Administrator of the Environmental
Protection Agency and any authorized representatives for issues related
to criteria pollutant standards. In the case of testing, compliance,
and approvals related to fuel consumption standards, ``we (us, our)''
includes the Administrator of the National Highway Traffic Safety
Administration (NHTSA) and any authorized representatives.
Sec. 1037.805 [Amended]
0
165. Amend Sec. 1037.805 by removing ``CH4'' and
``N2O'' from table 1 to paragraph (a).
0
166. Amend Sec. 1037.810 by revising paragraphs (c)(3) and (6) to read
as follows:
Sec. 1037.810 Incorporation by reference.
* * * * *
(c) * * *
(3) SAE J1263 MAR2010, Road Load Measurement and Dynamometer
Simulation Using Coastdown Techniques, Revised March 2010, (``SAE
J1263''); IBR approved for Sec. 1037.528 introductory text, (a), (b),
(c), (e), and (h).
* * * * *
(6) SAE J2263 MAY2020, (R) Road Load Measurement Using Onboard
Anemometry and Coastdown Techniques, Revised May 2020, (``SAE J2263'');
IBR approved for Sec. 1037.528 introductory text, (a), (b), (d), and
(f).
* * * * *
PART 1039--CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD
COMPRESSION-IGNITION ENGINES
0
167. The authority citation for part 1039 continues to read as follows:
Authority: 42 U.S.C. 7401-7671q.
0
168. Amend Sec. 1039.699 by revising paragraphs (a) and (n) to read as
follows:
Sec. 1039.699 Emission standards and certification requirements for
auxiliary power units for highway tractors.
(a) This section describes emission standards and certification
requirements for auxiliary power units (APU) installed on highway
tractors subject to
[[Page 7796]]
standards under 40 CFR 1037.102 starting in model year 2024.
* * * * *
(n) If a highway tractor manufacturer violates 40 CFR 1037.102 by
installing an APU from you that is not properly certified and labeled,
you are presumed to have caused the violation (see 40 CFR 1068.101(c)).
[FR Doc. 2026-03157 Filed 2-17-26; 8:45 am]
BILLING CODE 6560-50-P