# Air Plan Revisions; California; Heavy-Duty Vehicle Inspection and Maintenance Program
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Proposed rule.
**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 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.
[^1]*See* CAA section 110(a)(2)(A).
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.
[^2]*See* CAA section 110(k)(3).
[^3]*Id.;* CAA section 110(k)(4).
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.
[^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.
| Agency | Regulation title | Relevant sections of California Code of Regulations (CCR) | Adopted | Submitted |
| --- | --- | --- | --- | --- |
| CARB | Heavy-Duty Vehicle Inspection and Maintenance Program | Amended section: 13 CCR § 2193; New sections: 13 CCR §§ 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 | 12/09/2021 | 12/14/2022 |
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 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.
[^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.
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.
[^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”).
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.
[^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.
**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.,* PM <sub>10</sub> and PM <sub>2.5</sub> ). [^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.
[^12] See, generally, 40 CFR 81.305.
Mobile source emissions constitute a significant portion of overall emissions of ozone precursors, including volatile organic compounds (VOC) and oxides of nitrogen (NO <sub>X</sub> ), as well as direct PM and PM precursors, including NO <sub>X,</sub> sulfur dioxide (SO <sub>2</sub> ), 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 NO <sub>X</sub> emissions and 54% of on-road PM <sub>2.5</sub> 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 NO <sub>X</sub> . [^15] According to CARB, the HD I/M Regulation is intended to reduce PM <sub>2.5</sub> and NO <sub>X</sub> 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.
[^13] VOC and NO <sub>X</sub> are precursors responsible for the formation of ozone, and NO <sub>X</sub> and SO <sub>2</sub> are precursors for PM <sub>2.5</sub> . SO <sub>2</sub> belongs to a family of compounds referred to as sulfur oxides. PM <sub>2.5</sub> 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.
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.
[^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.
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 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]
[^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).
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]
[^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.
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).
[^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).
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.
[^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.
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 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 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.