[Federal Register Volume 90, Number 163 (Tuesday, August 26, 2025)]
[Proposed Rules]
[Pages 41525-41530]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-16325]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2025-0061; FRL-12606-01-R9]


Air Plan Revisions; California; Heavy-Duty Vehicle Inspection and 
Maintenance Program

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is proposing to 
partially approve and partially disapprove or, in the alternative, to 
fully approve a submission by the State of California to revise its 
State Implementation Plan (SIP) relating to the control of emissions 
from non-gasoline combustion vehicles over 14,000 pounds. EPA is 
proposing to disapprove the State's ``Heavy-Duty Inspection and 
Maintenance Regulation'' to the extent it applies to vehicles 
registered out-of-state or out-of-country. The EPA has substantial 
concerns that the State has not provided adequate assurances under 
Clean Air Act (CAA) section 110(a)(2)(E)(i) that implementation of the 
SIP is not prohibited by Federal law. EPA seeks comment on this and 
other aspects of this proposed rule. If finalized as a partial approval 
and partial disapproval, this rule would allow certain aspects of the 
covered State regulations to go into effect and would not trigger CAA 
section 179 sanctions because the submittal is not a required 
submission under CAA section 110(a)(2). If finalized as an approval, 
this rule would allow all

[[Page 41526]]

covered State regulations to go into effect.

DATES: Comments must be received on or before September 25, 2025.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2025-0061 at https://www.regulations.gov. In accordance with 5 
U.S.C. 553(b)(4), a summary of this rule may be found at 
Regulations.gov. For comments submitted at Regulations.gov, follow the 
online instructions for submitting comments. Once submitted, comments 
cannot be edited or removed from Regulations.gov. The EPA may publish 
any comment received to its public docket. Do not submit electronically 
any information you consider to be Confidential Business Information 
(CBI) or other information whose disclosure is restricted by statute. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the web, cloud, or other 
file sharing system). For additional submission methods, please contact 
the person identified in the FOR FURTHER INFORMATION CONTACT section. 
For the full EPA public comment policy, information about CBI or 
multimedia submissions, and general guidance on making effective 
comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets. If you need assistance in a language other than English or if 
you are a person with a disability who needs a reasonable accommodation 
at no cost to you, please contact the person identified in the FOR 
FURTHER INFORMATION CONTACT section.

FOR FURTHER INFORMATION CONTACT: Doris Lo, EPA Region IX, 75 Hawthorne 
St., San Francisco, CA 94105; telephone number: (415) 972-3959; email 
address: [email protected].

SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,'' 
and ``our'' refer to the EPA.

Table of Contents

I. Background
II. The State's Submittal
    A. What regulations did the State submit?
    B. Are there other versions of these regulations?
    C. What is the purpose of the submitted regulations?
III. The EPA's Evaluation and Action
    A. How is the EPA evaluating the rules and do the rules meet the 
evaluation criteria?
    B. Public Comment and Proposed Action
IV. Statutory and Executive Order Reviews

I. Background

    Under the CAA, the EPA establishes national ambient air quality 
standards (NAAQS) to protect public health and welfare. The EPA has 
established NAAQS for certain pervasive air pollutants including ozone, 
carbon monoxide, nitrogen dioxide, sulfur dioxide, lead, and 
particulate matter. Under CAA section 110(a)(1), States must submit 
plans that provide for the implementation, maintenance, and enforcement 
of the NAAQS within each State. Such plans are referred to as State 
Implementation Plans (SIPs), and revisions to those plans are referred 
to as ``SIP revisions.'' CAA section 110(a)(2) sets forth the content 
requirements for SIPs. Among the various requirements, SIPs must 
include enforceable emissions limitations and other control measures, 
means, or techniques as may be necessary or appropriate to meet the 
applicable requirements of the CAA.\1\ SIP revisions may be submitted 
to address specific CAA requirements (such as the elements and 
demonstrations required within an attainment plan), or, as with the 
State submittal addressed in this action, may be provided to 
demonstrate emissions reductions to support attainment.
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    \1\ See CAA section 110(a)(2)(A).
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    Upon receiving a SIP that meets the completeness criteria in CAA 
section 110(k)(1)(A), the EPA must determine whether the submission 
meets all applicable CAA requirements.\2\ The EPA must either approve, 
conditionally approve, approve in part or disapprove in part, or 
disapprove a complete State submission within twelve months.\3\ In 
addition to the limitations described above, CAA section 110(a)(2)(E) 
provides that a SIP must include ``necessary assurances'' that the 
State ``is not prohibited by any Federal or State law from carrying out 
such implementation plan or portion thereof'' and that the State or 
applicable State entity has adequate authority, personnel, and funding 
to carry out adequate implementation of the SIP.
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    \2\ See CAA section 110(k)(3).
    \3\ Id.; CAA section 110(k)(4).
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    Under California law, the California Air Resources Board (CARB) is 
the State agency responsible for adopting and submitting SIP revisions 
to the EPA for review. These include both local rules adopted by county 
and regional air districts (typically regulating stationary source 
emissions) and statewide regulations adopted by CARB and other State 
agencies. If approved into the SIP, submitted regulations become 
federally enforceable pursuant to CAA section 110(a)(2)(A).

II. The State's Submittal

A. What regulations did the State submit?

    CARB submitted the ``Heavy-Duty Inspection and Maintenance 
Regulation'' \4\ (``HD I/M Regulation'') as a revision to the 
California SIP on December 14, 2022.\5\ Table 1 identifies the 
regulatory sections included in the HD I/M Regulation and addressed by 
this proposal with the dates that they were adopted by CARB and 
submitted to the EPA.
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    \4\ The State of California more commonly refers to the HD I/M 
Regulation as the ``Clean Truck Check.'' See, e.g., CARB, Clean 
Truck Check (HD I/M), https://ww2.arb.ca.gov/our-work/programs/CTC 
(last visited on January 27, 2025).
    \5\ Letter (with enclosures) dated December 7, 2022, from Steven 
S. Cliff, Ph.D., Executive Officer, CARB, to Martha Guzman, Regional 
Administrator, EPA Region IX (submitted electronically December 14, 
2022). The letter and enclosures, which include the HD I/M 
Regulation, among other materials, are included in the docket for 
this rulemaking.

                                         TABLE 1--Submitted Regulations
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                                                              Relevant sections of
           Agency                  Regulation title            California Code of         Adopted     Submitted
                                                               Regulations (CCR)
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CARB........................  Heavy-Duty Vehicle         Amended section: 13 CCR Sec.    12/09/2021   12/14/2022
                               Inspection and              2193; New sections: 13 CCR
                               Maintenance Program.       Sec.  Sec.   2195, 2195.1,
                                                          2196, 2196.1, 2196.2,
                                                          2196.3, 2196.4, 2196.5,
                                                          2196.6, 2196.7, 2196.8,
                                                          2197, 2197.1, 2197.2,
                                                          2197.3, 2198, 2198.1,
                                                          2198.2, 2199, and 2199.1.
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    The HD I/M Regulation incorporates by reference the ``California 
Standards for Heavy-Duty Remote On-Board Diagnostic Devices'' (``OBD 
Standards''). CARB approved the HD I/M Regulation on December 9, 2021, 
through

[[Page 41527]]

Resolution 21-29. Following minor non-substantive edits by CARB 
staff,\6\ CARB formally adopted the final HD I/M Regulation and OBD 
Standards on August 22, 2022, through CARB Executive Order R-22-002.
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    \6\ CARB, Addendum to the Final Statement of Reasons for 
Rulemaking, ``Public Hearing to Consider Proposed Heavy-Duty 
Inspection and Maintenance Regulation,'' October 4, 2022.
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    CARB's SIP submittal package for the HD I/M Regulation includes 
CARB Resolution 21-29,\7\ Executive Order R-22-002, public notice of 
CARB's hearing on the proposed SIP revision, CARB's Initial Statement 
of Reasons and appendices (``Staff Report''),\8\ public comments and 
responses, the Final Statement of Reasons and addendum, and emission 
reduction estimates calculated using the State's ``EMission FACtor'' 
(EMFAC) model.
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    \7\ CARB Board Resolution 21-29, December 9, 2021.
    \8\ CARB, Staff Report: Initial Statement of Reasons, ``Public 
Hearing to Consider the Proposed Heavy-Duty Inspection and 
Maintenance Regulation,'' October 8, 2021 (``Staff Report'').
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    On June 14, 2023, the submittal from CARB was deemed by operation 
of law to meet the completeness criteria in 40 CFR part 51, appendix V, 
which must be met before formal EPA review pursuant to CAA section 
110(k)(1).

B. Are there other versions of these regulations?

    On May 10, 2022, we approved an earlier version of the Heavy-Duty 
Vehicle Inspection Program \9\ and a Periodic Smoke Inspection Program 
\10\ into the California SIP.\11\ The current SIP submittal was 
intended to replace these previously approved revisions to the SIP; if 
the EPA finalizes a partial disapproval of the current submittal, the 
partially approved aspects of the revision would become the SIP and the 
earlier versions of the Heavy-Duty Vehicle Inspection Program and the 
Periodic Smoke Inspection Program would remain in the SIP only to the 
extent not superseded by the partially approved aspects of the SIP 
revisions.
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    \9\ California Code of Regulations Title 13, Division 3, Chapter 
3.5.
    \10\ California Code of Regulations Title 13, Division 3, 
Chapter 3.6.
    \11\ 87 FR 27949.
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C. What is the purpose of the submitted regulations?

    Based on ambient data collected at numerous sites throughout the 
State, the EPA has designated certain areas within California as 
nonattainment for the ozone NAAQS and the particulate matter (PM) 
NAAQS, which includes both coarse and fine particulate matter (i.e., 
PM10 and PM2.5).\12\ Several areas in California 
that had been designated as nonattainment for the carbon monoxide NAAQS 
have been redesignated by the EPA to attainment because these areas 
have attained the standard and are subject to an approved maintenance 
plan demonstrating how the State will maintain the carbon monoxide 
standard into the future.
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    \12\ See, generally, 40 CFR 81.305.
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    Mobile source emissions constitute a significant portion of overall 
emissions of ozone precursors, including volatile organic compounds 
(VOC) and oxides of nitrogen (NOX), as well as direct PM and 
PM precursors, including NOX, sulfur dioxide 
(SO2), and carbon monoxide in the various air quality 
planning areas within California.\13\ Although heavy-duty vehicles 
comprise about 3% of the State's vehicle fleet, they constitute 52% of 
the on-road NOX emissions and 54% of on-road 
PM2.5 emissions.\14\ In addition, out-of-state or out-of-
country heavy-duty vehicles are approximately half of the total heavy-
duty vehicles travelling in the State and constitute approximately 30% 
of heavy-duty NOX.\15\ According to CARB, the HD I/M 
Regulation is intended to reduce PM2.5 and NOX 
emissions from heavy-duty non-gasoline combustion vehicles operating in 
California to further ozone and PM attainment throughout the State.\16\ 
In establishing the applicable NAAQS, the EPA has concluded that at 
elevated levels, ozone and PM harm human health and the environment by 
contributing to premature mortality, aggravation of respiratory and 
cardiovascular disease, decreased lung function, visibility impairment, 
and damage to vegetation and ecosystems.
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    \13\ VOC and NOX are precursors responsible for the 
formation of ozone, and NOX and SO2 are 
precursors for PM2.5. SO2 belongs to a family 
of compounds referred to as sulfur oxides. PM2.5 
precursors also include VOC and ammonia. See 40 CFR 51.1000.
    \14\ See, Staff Report at I-2.
    \15\ Id. at II-2.
    \16\ See Staff Report at II-1.
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    The HD I/M Regulation establishes a comprehensive I/M program for 
HD vehicles driven in the State of California to ensure that vehicle 
emissions control systems on these vehicles are operating as designed 
and are repaired quickly if they malfunction. CARB has explained that 
this regulatory revision builds on CARB's current heavy-duty inspection 
programs, including building on and replacing the Heavy-Duty Vehicle 
Inspection Program and Periodic Smoke Inspection regulations for heavy-
duty vehicles.
    The HD I/M Regulation applies to all non-gasoline combustion 
vehicles above 14,000 gross vehicle weight rating (GVWR) that operate 
in California. Unlike virtually all prior CARB regulations and similar 
regulations adopted by other States, however, the regulation submitted 
for review would also apply to vehicles registered out-of-state and 
out-of-country that operate within the State of California for almost 
any length of time.\17\ Some vehicle categories are exempted, including 
zero-emission vehicles, emergency and military tactical vehicles, and 
other classes defined by use or purpose.
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    \17\ The HD I/M regulation permits entities subject to the rule 
to apply once per calendar year for a five-day ``pass through'' 
exception which must be granted in each instance and on an 
individualized basis. The EPA notes that California has not provided 
assurances that this additional compliance step meaningfully changes 
the coverage of the HD I/M regulations.
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    The HD I/M Regulation requires owners of HD vehicles operating in 
California (including out-of-state vehicles) to report owner and 
vehicle information to CARB. It also requires owners of HD vehicles to 
demonstrate that their vehicle emissions control systems are properly 
functioning through vehicle compliance tests completed by CARB-approved 
testers and periodically submit vehicle compliance test results to CARB 
to show compliance with the HD I/M regulation. Vehicles equipped with 
on-board diagnostic (OBD) systems can be tested using OBD data, while 
older non-OBD vehicles are subject to smoke opacity and visual 
inspections. Vehicle owners are also required to have a valid HD I/M 
compliance certificate with the vehicle while operating in California, 
which they must present to a CARB inspector and/or CHP officer upon 
request.
    The regulation also establishes a referee testing network to 
provide independent evaluations of heavy-duty vehicles and services for 
vehicles with inspection incompatibilities or compliance issues. 
Finally, the regulation describes procedures for HD I/M roadside 
inspections, including roadside monitoring and field inspections.

III. The EPA's Evaluation and Action

A. How is the EPA evaluating the rules and do the rules meet the 
evaluation criteria?

    The EPA has evaluated the HD I/M Regulation against the applicable 
procedural and substantive requirements of the CAA for SIPs and SIP 
revisions and proposes to find that the HD I/M Regulation meets the 
applicable requirements to the extent the substantive requirements 
apply to vehicles registered in California. Among other requirements, a 
SIP must include

[[Page 41528]]

enforceable emission limitations and other control measures, means, or 
techniques, as well as schedules and timetables for compliance, that 
may be necessary to meet the requirements of the Act.\18\ The EPA 
proposes to find that the State's I/M measures generally meet the 
requirements of the CAA and the EPA's implementing regulations with 
respect to vehicles registered in California including because it 
satisfies the applicable requirements of CAA sections 110(a)(2)(A) and 
(E).\19\
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    \18\ See CAA section 110(a)(2)(A).
    \19\ See EPA, ``Technical Support Document for EPA's Rulemaking 
for the California State Implementation Plan--California Air 
Resources Board Heavy-Duty Inspection and Maintenance Regulation,'' 
March 3, 2025 (included in the docket for this proposed action).
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    However, the EPA has substantial concerns that the HD I/M 
Regulation does not provide necessary assurances that the State is not 
prohibited by any provision of Federal or State law from carrying out 
such SIP or a portion thereof \20\ to the extent the HD I/M Regulation 
purports on its face to regulate vehicles that merely pass through or 
operate within California for almost any length of time. For the 
reasons set out below, the EPA also has substantial concerns that 
approving the extraterritorial reach of the HD I/M Regulation could 
interfere with other applicable requirements of the Act concerning 
attainment and reasonable further progress (RFP), as well as the 
implementation of SIPs submitted by other States and approved by the 
EPA.\21\
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    \20\ See CAA section 110(a)(2)(E)(i).
    \21\ See id. CAA section 193, which prohibits any pre-1990 SIP 
control requirement relating to nonattainment pollutants in 
nonattainment areas from being modified unless the SIP is revised to 
ensure equivalent or greater emission reductions of such air 
pollutants, does not apply to the HD I/M Regulation because it 
includes only new regulations and amended regulations that were 
previously approved into the California SIP in 2022, and thus, does 
not constitute an amendment to a pre-1990 SIP control requirement.
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    Unlike other SIP provisions that apply to sources that are 
registered within the State, the HD I/M Regulation adds requirements on 
heavy-duty vehicles that are registered in other States that merely 
pass through or do business within California for almost any length of 
time. The EPA has substantial concerns that this aspect of the 
regulation is prohibited by the U.S. Constitution and proposes to 
disapprove this portion of the SIP because EPA finds that California 
has not provided the necessary assurances that, if approved, the SIP 
could be implemented consistent with Federal law.
    Here, the Commerce Clause appears to prohibit the implementation of 
the HD I/M Regulation because its extraterritorial reach burdens 
interstate commerce. The U.S. Supreme Court has explained that the 
Commerce Clause contains ``a negative command'' that forbids ``certain 
state [economic regulations] even when Congress has failed to legislate 
on the subject.'' Okla. Tax Comm'n v. Jefferson Lines, Inc., 514 U.S. 
175, 179 (1995). Generally applicable State regulations that further a 
legitimate interest and burden interstate commerce incidentally are 
nevertheless invalid when ``the burden imposed on such commerce is 
clearly excessive in relation to the putative local benefits.'' Pike v. 
Bruce Church, Inc., 397 U.S. 137, 142 (1970). Thus, ``even 
nondiscriminatory burdens on commerce'' may run afoul of the Commerce 
Clause ``on a showing that those burdens clearly outweigh the benefits 
of a state or local practice.'' Nat'l Pork Producers Council v. Ross, 
598 U.S. 356, 392 (2023) (Roberts, C.J., concurring in part and 
dissenting in part).\22\ Burdens on interstate commerce are of 
particular concern when they impose costs on interstate trade, see, 
e.g., Kassel v. Consol. Freightways Corp., 450 U.S. 662, 674 (1981) 
(plurality op.); Raymond Motor Transp., Inc. v. Rice, 434 U.S. 429, 445 
& n.21 (1978), where ``the nature of'' the market means that a State 
regulation generates costs whether or not participants sell into the 
regulating State, Nat'l Pork Producers, 598 U.S. at 400 (Roberts, C.J., 
concurring in part and dissenting in part), and where a State 
regulation targets ``instrumentalities of interstate transportation--
trucks, trains, and the like,'' id. at 379 n.2, 380 (plurality op.); 
accord id. at 392 (Sotomayor, J., concurring in part).
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    \22\ In National Pork Producers, ``six Justices of [the] Court 
affirmatively retain[ed] the longstanding Pike balancing test for 
analyzing dormant Commerce Clause challenges to state economic 
regulations.'' 598 U.S. at 403 (Kavanaugh, J., concurring in part 
and dissenting in part); see id. at 391 (Sotomayor, J., joined by 
Kagan, J., concurring in part); id. at 394 (Roberts, C.J., joined by 
Alito, Kavanaugh, Jackson, JJ., concurring in part and dissenting in 
part).
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    The impact of California's HD/IM Regulation on vehicles registered 
out of state and on interstate shipping is undoubtably significant. The 
HD I/M Regulation adds significant costs to operation of heavy-duty 
vehicles in California. According to a CARB's Staff Report, the HD I/M 
Regulation will cost $4.12 billion between 2023-2050, with a maximum 
annual cost of $350 million in 2024. Much of these costs relate to HD 
vehicle testing, repair, and compliance fee costs.\23\ CARB also 
estimated the total direct costs on a typical California fleet (seven 
vehicles) to be $772 to $2,180 annually.\24\ CARB estimated the total 
direct costs on single-vehicle fleets (i.e., small businesses, as 
defined by CARB) to be $225 to $701 annually.\25\ To the extent the HD 
I/M Regulation applies to out-of-state vehicles that pass through or 
operate within California for almost any length of time, this cost 
structure would also be imposed on other States and regulated entities 
in those States. The EPA notes that many heavy-duty vehicles covered by 
the regulations at issue are used for purposes of interstate shipping, 
and that maintenance of those vehicles could occur in any number of 
States, meaning the burdens of compliance could be felt across the 
country and even in other countries.
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    \23\ Staff Report at IX-14.
    \24\ Staff Report at IX-18-20. CARB states according to vehicle 
registration data, of fleets consisting of at least three vehicles, 
75 percent have four to ten vehicles.
    \25\ Staff Report at IX-20-21. CARB defines ``small businesses'' 
as HD fleets consisting of one to three vehicles, and that 79 
percent of ``small businesses'' consist of single-vehicle fleets. 
CARB further states that based on vehicle registration data small 
businesses constitute approximately 89 percent of fleets and 44 
percent of the vehicle population in California.
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    The EPA's concern in this respect is heightened by the structure of 
CAA section 110 and the way in which an approval of this provision 
would operate on the ground. In effect, an approval would delegate to 
California the ability to enforce the State's I/M requirements 
throughout the nation to the extent a vehicle passes through or 
operates within the State for almost any length of time. As a result, 
an approval would effectively force regulated entities in other States 
to comply with California's HD I/M requirements, rather than the 
applicable requirements in their respective States, including 
requirements approved by the EPA pursuant to the CAA. That interstate 
regulatory function is vested exclusively in Congress by the Commerce 
Clause, and the result of EPA's approval under the circumstances risks 
precisely the abrogation of Federal authority that the Supreme Court 
has held the Commerce Clause prohibits.
    Moreover, the extraterritorial reach of the HD I/M regulation 
appears to abrogate the foreign relation powers vested exclusively in 
the Federal Government by the U.S. Constitution. The EPA is aware that 
vehicles registered in Mexico and Canada regularly pass through or do 
business in California for the purposes of international trade, 
tourism, and other forms of economic activity. California shares a land 
border with Mexico, and Mexico maintains a consulate within

[[Page 41529]]

the State, meaning that vehicles registered in Mexico are also passing 
through or doing business in California for diplomatic purposes. The HD 
I/M regulation does not include an international exclusion or narrower 
exclusion for diplomatic purposes, for example. As a result, the HD I/M 
regulation may already be in conflict with applicable international 
treaties and conventions adopted by the United States for trade and 
diplomatic purposes, and the State has not provided necessary 
assurances that adoption into the SIP would not be prohibited by the 
Constitution's assignment of foreign affairs authority to Congress and 
the President, respectively.
    For many of the same reasons, the EPA proposes to partially 
disapprove because it finds that California has not provided necessary 
assurances that the extraterritorial reach of the HD I/M regulation 
into other States does not violate CAA section 110 and related 
provisions by infringing upon, or frustrating the implementation of, 
SIPs submitted by other States and approved by the EPA. Some States 
have HD I/M provisions that differ from California's in material 
respects but none of these have been approved into SIPs. If approved in 
all respects, California's HD I/M Regulation would be federally 
enforceable to the same extent as other State I/M regulations 
potentially approved by the EPA in the future pursuant to CAA section 
110. The result is potentially multiple conflicting sources of 
obligations that are enforceable both within the respective States and 
federally under the CAA. EPA solicits comment on these potential 
conflicts and whether they would frustrate the ability of other States 
to implement their SIPs and achieve and attain compliance with the 
NAAQS.
    Accordingly, the EPA is proposing to partially disapprove the 
State's HD I/M Regulation to the extent it applies to vehicles 
registered out-of-state or out-of-country, and is proposing to approve 
the remainder. The EPA acknowledges, however, that the extraterritorial 
reach of the State's regulation is unusual in the SIP context and that 
the EPA's response would necessarily be the first instance in which the 
Agency has disapproved a SIP on this basis. We therefore seek comment 
on all aspects of this proposal, including whether extraterritorial 
application of California's regulation would be prohibited by Federal 
law on the bases presented here, as well as on other bases under 
Federal or State law. We also seek comment on any ways in which Federal 
enforcement of California's HD I/M Regulation could conflict with the 
approved SIPs for other States. Moreover, we seek comment on the 
aspects of the submission that the EPA proposes to partially approve, 
that is, the application of the HD I/M Regulation to vehicles 
registered in California.
    In the alternative, the EPA proposes to approve if the State's 
submission sufficiently demonstrates that implementation of the HD I/M 
Regulation would not be prohibited by Federal or State law. The EPA 
seeks comment on whether California has provided necessary assurances 
that its submission meets the requirements of CAA section 
110(a)(2)(E)(i) and the extent and nature of potential Federal and 
State law prohibitions on implementing California's submission as 
proposed.

B. Public Comment and Proposed Action

    The EPA proposes to partially disapprove the submitted rules 
because, while they fulfill many of the relevant CAA requirements, the 
application of the rules to vehicles registered out of state and out of 
country appears to be prohibited by Federal law. We will accept 
comments from the public on this proposal until September 25, 2025.
    Neither sanctions nor a Federal Implementation Plan (FIP) would be 
imposed should the EPA finalize this partial disapproval. Sanctions 
would not be imposed under CAA section 179(b) because the submittal of 
the HD I/M Regulation is discretionary (i.e., not required to be 
included in the SIP), and the EPA would not promulgate a FIP under CAA 
section 110(c)(1) because the disapproval does not reveal a deficiency 
in the SIP for the area that such a FIP must correct. Note that the 
submitted rule has been adopted by the State of California, and a final 
partial disapproval by the EPA would not by its own force prevent the 
State from attempting to enforce it within California.

IV. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders 
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This is a significant regulatory action as per Executive Order 
12866 and was submitted to the Office of Management and Budget (OMB) 
for review.

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

    This action is not expected to be an Executive Order 14192 
regulatory action. The proposed SIP partial disapproval, if finalized, 
will not in-and-of itself create any new requirements but will simply 
disapprove certain State requirements for inclusion in the SIP. The 
proposed SIP approval, if finalized, would not impose any requirements, 
but rather would determine that the State's submission complies with 
the CAA and applicable regulations.

C. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the PRA.

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. This 
action will not impose any requirements on small entities. The proposed 
SIP partial disapproval, if finalized, will not in-and-of itself create 
any new requirements but will simply disapprove certain State 
requirements for inclusion in the SIP. The proposed SIP approval, if 
finalized, would not impose any requirements, but rather would 
determine that the State's submission complies with the CAA and 
applicable regulations.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain any unfunded mandate as described in 
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 
small governments. This action proposes to disapprove pre-existing 
requirements under state or local law, and imposes no new requirements. 
Accordingly, no additional costs to state, local, or tribal 
governments, or to the private sector, result from this action.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

G. Executive Order 13175: Coordination With Indian Tribal Governments

    This action does not have Tribal implications, as specified in 
Executive Order 13175, because the SIP revision that the EPA is 
proposing to disapprove

[[Page 41530]]

would not apply on any Indian reservation land or in any other area 
where the EPA or an Indian Tribe has demonstrated that a Tribe has 
jurisdiction, and will not impose substantial direct costs on Tribal 
governments or preempt Tribal law. Thus, Executive Order 13175 does not 
apply to this action.

H. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    The EPA interprets Executive Order 13045 as applying only to those 
regulatory actions that concern environmental health or safety risks 
that the EPA has reason to believe may disproportionately affect 
children, per the definition of ``covered regulatory action'' in 
section 2-202 of the Executive Order. Therefore, this action is not 
subject to Executive Order 13045 because this proposed SIP disapproval, 
if finalized, will not in-and-of itself create any new regulations, but 
will simply partially disapprove or approve certain State requirements 
for inclusion in the SIP, thereby determining whether the requirements 
are or are not federally enforceable. Furthermore, the EPA's Policy on 
Children's Health does not apply to this action.

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

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution or use of energy. This action on an inspection and 
maintenance measure for heavy-duty vehicles in California does not 
relate to or affect energy supply, distribution, or use.

J. National Technology Transfer and Advancement Act (NTTAA)

    Section 12(d) of the NTTAA directs the EPA to use voluntary 
consensus standards in its regulatory activities unless to do so would 
be inconsistent with applicable law or otherwise impractical. The EPA 
believes that this action is not subject to the requirements of section 
12(d) of the NTTAA because application of those requirements would be 
inconsistent with the CAA.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide, 
Incorporation by reference, Intergovernmental relations, Nitrogen 
oxides, Ozone, Particulate matter, Reporting and recordkeeping 
requirements.

    Dated: August 20, 2025.
Joshua F.W. Cook,
Regional Administrator, Region IX.
[FR Doc. 2025-16325 Filed 8-25-25; 8:45 am]
BILLING CODE 6560-50-P