EPA finalizes landmark rescission of 2009 GHG Endangerment Finding for motor vehicles

This action also rescinds a number of related compliance and reporting requirements including testing, reporting, certification obligations, and compliance flexibilities (e.g., credit programs). EPA also eliminates the off-cycle credit program, ending the ability for manufacturers to generate off-cycle credits for various vehicle features, including the start-stop feature. Importantly, the repeal does not affect criteria pollutant emissions standards, mobile source air toxics standards, or corporate average fuel economy (CAFE) standards. Nor does the rule rescind other GHG endangerment findings issued by EPA for different source categories, such as aircraft engines or stationary sources (although separate actions from EPA to rescind those findings are either in process or anticipated).

President Trump and EPA Administrator Zeldin announced the repeal at an event held at the White House, calling it the largest deregulatory action in U.S. history. In the final rule, EPA’s primary justification for repealing the Endangerment Finding is that it lacks authority under CAA section 202(a) to prescribe emission standards based on global climate change and, therefore, there is no legal basis for the Endangerment Finding and resulting regulations. EPA clarifies that the repeal is not based on a new finding under CAA section 201(a)(1), but rather that EPA lacks statutory authority to make such a finding in the first instance. EPA characterizes the 2009 finding as legally invalid ab initio. Moreover, EPA asserts that the repeal would result in significant savings for consumers and restore economic choice for vehicle purchases.

Beyond lacking statutory authority, EPA concludes that regulating GHG emissions from new motor vehicles and engines would not materially impact climate change and that maintaining GHG standards “would be unreasonable given their futility and the immense burdens they place on regulated parties, consumers, and the economy.” Final Rule, at 7688. EPA emphasizes, however, that these considerations reinforce—but do not independently determine—its decision to rescind the Endangerment Finding.

Importantly, EPA did not finalize the alternative bases for repealing the GHG standards, as initially proposed. In particular, EPA did not finalize the proposed basis to repeal all GHG emission standards because there is no “requisite technology” for emission control from motor vehicles and engines that can address global climate change concerns. Nor did EPA finalize the alternative basis 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. EPA had initially proposed rescinding the finding because its original analysis of the scientific record and data was unreasonable and subsequent legal and scientific developments “cast significant doubt on the reliability of the findings.” Proposed Rule, 90 Fed. Reg. 36,288 (Aug. 1, 2025). EPA expressly declined to rest the final rule on any reevaluation of climate science, notwithstanding its discussion of scientific and technical considerations in the preamble.

EPA originally issued the Endangerment Finding in 2009 during the Obama Administration in response to the Supreme Court’s 2007 decision in Massachusetts v. EPA, 549 U.S. 497 (2007). The Supreme Court case arose after states petitioned EPA to request that the agency regulate CO2 and other greenhouse gas emissions from new motor vehicles. The Endangerment Finding contained two key findings regarding the regulation of GHGs under the CAA: (1) “elevated concentrations of [GHGs] . . . may reasonably be anticipated to endanger the public health”; and (2) “emissions of the well-mixed [GHGs] from new motor vehicles contribute to the air pollution that may reasonably be anticipated to endanger public health and welfare . . . .” See EPA Final Rule, Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act, 74 Fed. Reg. 66,496, 66,516, 66,537 (Dec. 15, 2009).

In the final rule, EPA asserts that the 2009 Endangerment Finding “rested on a profound misreading” of Massachusetts v. EPA. EPA emphasizes that the Supreme Court held only that greenhouse gases fall within the Act’s broad definition of “air pollutant” and that EPA must exercise judgment where it possesses statutory authority to regulate. According to EPA, the Court did not decide—and did not confer—authority to regulate motor vehicle emissions for the purpose of addressing global climate change, and the 2009 Endangerment Finding improperly assumed that such authority existed. EPA further concludes that whether and how to address climate change through motor vehicle regulation is a question for Congress to resolve in the first instance. As proposed, EPA relied on Supreme Court precedent from Loper Bright Enterprises v. Raimondo, 603 U.S. 369 (2024), West Virginia v. EPA, 597 U.S. 697 (2022), and Utility Air Regulatory Group v. EPA, 573 U.S. 302 (2014) (among others) to assert that the CAA is silent or ambiguous with regard to addressing global climate change and, as a result, EPA lacks the “clear congressional authorization” required under the major questions doctrine.

The final rule also addresses the interaction between rescission of the Endangerment Finding and state authority, stating EPA’s view that existing CAA preemption provisions applicable to motor vehicle emission standards remain in effect notwithstanding the repeal of federal GHG standards.

Legal challenges to the rule must be filed by April 20, 2026 in the U.S. Court of Appeals for the D.C. Circuit. EPA included severability provisions in the final rule, stating its intent that the remaining portions of the rule remain in effect should any aspect be vacated or remanded.

The final action is effective on April 20, 2026. Additional materials related to the final rule and docket (EPA-HQ-OAR-2025-0194) are available on EPA’s website.

Key takeaways

• EPA has rescinded the 2009 GHG Endangerment and Cause or Contribute Findings as applied to new motor vehicles and engines under Clean Air Act section 202(a) and repealed all federal greenhouse gas emission standards and associated compliance programs for light , medium , and heavy duty vehicles beginning with model year 2012. The rescission eliminates testing, reporting, certification, and averaging, banking, and trading programs, including the off cycle credit program, as a direct consequence of repealing the vehicle GHG standards.
• The final rule rests on a legal—not scientific—rationale. EPA concludes that it lacks statutory authority under section 202(a) to regulate motor vehicle emissions for the purpose of addressing global climate change and therefore lacked authority to issue the Endangerment Finding in the first instance. EPA expressly declined to finalize alternative rationales based on climate science or discretionary reconsideration of the original finding.
• EPA asserts that its action is consistent with, rather than contrary to, Massachusetts v. EPA. EPA maintains that the Supreme Court held only that greenhouse gases fall within the Act’s definition of “air pollutant” and did not decide whether section 202(a) authorizes regulation to address global climate change, a question EPA now characterizes as requiring clear congressional authorization.
• Other Clean Air Act programs remain unchanged. The rule does not affect criteria pollutant standards, mobile source air toxics standards, CAFE requirements, or other EPA endangerment findings applicable to non vehicle source categories.
• EPA anticipates litigation and asserts continued preemption of state vehicle GHG standards. The agency states its view that existing Clean Air Act preemption provisions continue to apply notwithstanding the repeal of federal GHG standards, an issue that is expected to be litigated. Challenges to the rule must be filed in the D.C. Circuit by April 20, 2026.

Authored by Joanne Rotondi, Hannah Graae, and Allisa Newman.