On August 1, 2025, the Environmental Protection Agency (EPA) published in the Federal Register (Vol. 90 No. 146) a Proposal to repeal all greenhouse gas (GHG) emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines to enforce the latest reading of Clean Air Act (CAA) Section 202(a); 40 CFR Parts 85, 86, 600, 1036, 1037, and 1039. The EPA proposes that CAA Section 202(a) does not authorise the EPA to prescribe emission standards to address global climate change concerns and proposes to rescind the Administrator's prior findings in 2009 that GHG emissions from new motor vehicles and engines contribute to air pollution which may endanger public health or welfare. The EPA further proposes to rescind the Administrator's prior findings in 2009 because the EPA unreasonably analysed the scientific record and because developments cast significant doubt on the reliability of the findings. EPA proposes to repeal all GHG emission standards on the basis that no requisite technology for vehicle and engine emission control can address the global climate change concerns identified in the findings without risking greater harms to public health and welfare.
In 2009, the EPA took the unprecedented step of asserting authority to regulate GHG emissions in a standalone action titled ‘Endangerment and Cause or Contribute Finding for Greenhouse Gases Under Section 202(a) of the Clean Air Act,’ 74 FR 66496 (Dec. 15, 2009) (Endangerment Finding). 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 its GHG initiative into additional CAA programs.
In Utility Air Regulatory Group (UARG), v. EPA, 573 U.S. 302 (2014) the Supreme Court rejected EPA’s attempt to extend GHG emission standards to stationary sources subject to Title I and Title V requirements, including after the EPA admitted that applying the statutory scheme as written to GHG emissions from most covered stationary sources would be unworkable. And in West Virginia v. EPA, 597 U.S. 697 (2022), the Court vacated EPA’s 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 EPA actions at issue implicated the major questions doctrine, and that Congress must clearly authorise 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 compliance costs on American businesses and consumers. Meanwhile, global GHG concentrations in the upper atmosphere have continued to rise, driven primarily by increased emissions from foreign sources, all without producing the degree of adverse impacts to public health and welfare in the United States that the EPA anticipated in the 2009 Endangerment Finding.
The Administrator's review of the relevant information, including scientific literature, gave rise to serious concerns that the EPA actions taken to regulate GHG emissions from new motor vehicles and engines exceed our statutory authority under CAA Section 202(a) and are otherwise inappropriate. Continuing to impose billions of dollars in regulatory costs on American businesses and consumers without an adequate legal basis would threaten to undermine public confidence in EPA activities and commitment to fulfilling the Agency's core mission: protecting human health and the environment. The EPA has expended significant resources implementing the GHG regulatory program for mobile sources and attempting to expand its GHG regulatory program to stationary sources with limited success in the courts and no apparent real-world results, often at the expense of programs that fall squarely within our statutory authority. Prompt action is needed to address these concerns with the benefit of public participation.
The EPA now proposes to rescind the Endangerment Finding and all resulting GHG emission standards for new motor vehicles and engines, including the light-duty, medium-duty, and heavy-duty vehicle and engine standards for Model Years (MY) 2012 to 2027 and beyond.
If finalised, this action would rescind the 2009 Endangerment Finding for GHGs emitted by new motor vehicles and new motor vehicle engines under CAA Section 202(a) (74 FR 66496). This Proposal would also rescind denials of Petitions for Reconsideration of the Endangerment Finding in 2022 and 2010 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). Although the 2022 and 2010 petition denials have no prospective legal effect, it is proposed to rescind them for the sake of consistency and to lessen potential confusion regarding the EPA's proposed action. The denials reflect many of the same legal and scientific flaws the EPA propose to correct by rescinding the Endangerment Finding. The EPA seeks comment on the impact of the denials, if any, and on whether the denials were legally flawed for additional reasons not explicitly explored in this Proposal. In addition, as a result of these proposed changes, the EPA would no longer have a basis for issuing or retaining GHG emission standards for new motor vehicles and new motor vehicle engines, including for MYs that have completed manufacture but are subject to ongoing obligations. As discussed elsewhere in the preamble, the EPA is reconsidering additional endangerment findings and GHG emission standards issued under distinct provisions of the CAA in separate rulemakings and is not reopening or proposing to modify those additional findings and standards in this proceeding.
In connection with the proposed rescission of the Endangerment Finding, this action would remove all existing regulations that require new motor vehicle and new motor vehicle engine manufacturers to measure, report, or comply with GHG emission standards. Specifically, the EPA proposes to remove regulations in 40 CFR Parts 85, 86, 600, 1036, and 1037 pertaining to the control of GHG emissions from light-, medium-, and heavy-duty vehicles and engines, including emission standards, test procedures, averaging, banking, and trading requirements (ABT), reporting requirements, and fleet-average emission requirements. As a result of these proposed changes, motor vehicle and engine manufacturers would 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, the EPA are not proposing to 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. The EPA seeks comment on whether any elements of the regulations, test procedures, or GHG emission models that are proposed for removal should remain to support programs unrelated to the GHG emission standards and why the preservation of such an element is necessary to support the unrelated program or programs.
The EPA requests public comments on this Proposal (some sections specifically identified) to ensure that the all aspects of these actions are considered and are based on accurate, current data and technology. Comments must be received on or before September 15, 2025. Comments on the information collection provisions submitted to the Office of Management and Budget (OMB) under the Paperwork Reduction Act (PRA) are best assured of consideration by OMB if OMB receives a copy of your comments on or before September 2, 2025.
This Proposal is available on InterRegs.NET for our US Federal subscribers and is also available at Selectregs.