The U.S. EPA on July 29 released a proposed rule to repeal the agency’s 2009 Endangerment Finding, which forms the legal basis for the agency’s greenhouse gas (GHG) regulations. If finalized, the proposal would all repeal all resulting GHG regulations for motor vehicles and engines.&nbsp;The Endangerment Finding is a legal determination made by the EPA in 2009 that GHG emissions endanger human health and the environment. It specifically addresses carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride emissions and allows the EPA to regulate the emissions of those six GHGs under the Clean Air Act.The EPA’s process to issue the Endangerment Finding spanned more than a decade and was first spurred by a petition for rulemaking filed by more than a dozen environmental, renewable energy and other organizations in 1999 calling on the agency to regulate GHG emissions from new motor vehicles. That petition was made under a CAA statute that states the EPA “shall” issue standards for air-pollutant emissions from new motor vehicles that “cause, or contribute to, air pollution which may be reasonably be anticipated to endanger public health or welfare.”&nbsp;The EPA in 2003 denied the petition, but the petitioners and a group of intervenor states filed lawsuits challenging the denial. The issue eventually reached the U.S. Supreme Court, which in 2007 ruled GHGs are air pollutants under the CAA. Under the Supreme Court’s decision, the EPA was directed to determine if GHGs pose a danger to public health or welfare, or whether the science was too uncertain to make a decision. The agency soon after began work to assess the science of effects of GHGs, and in 2008 issued an advanced notice of proposed rulemaking to regulate GHG emissions under the CAA. More than 200,000 comments were filed during a 120-day public comment period. The EPA in 2009 issued its Proposed Endangerment finding and gathered more than 380,000 comments during a 60-day public comment period. Later that year, the EPA issued proposed light-duty vehicle GHG standards and a final Endangerment Finding.&nbsp;According to the EPA, it has denied 14 petitions filed between 2009 and 2019 seeking a reconsideration of the Endangerment Finding. The U.S. Court of Appeals for the D.C. Circuit in 2012 upheld the Endangerment Finding as well as related GHG regulations issued under the CAA for passenger vehicles and permitting for stationary sources. The EPA <a href="https://biomassmagazine.com/articles/epa-takes-initial-step-in-regulating-aircraft-engine-ghgs-13522">in 2016 also affirmed Endangerment Finding</a> based on a review of updated science as part of an initial step the agency took in regulating aircraft engine GHGs.&nbsp;The EPA has relied on the Endangerment Finding to set GHG emissions standards for cars and light trucks, power plants, and oil and gas facilities.Most recently, the EPA in 2024 issued a final rule setting multi-pollutant emissions standards for model year (MY) 2027 and later light-duty and medium-duty vehicles. That rulemaking has been criticized as creating a de facto mandate for electric vehicles.&nbsp;The EPA’s July 29 proposal aims to rescind the Endangerment Finding on the grounds of new scientific data that the EPA said “challenge the assumptions behind the 2009 Endangerment Finding.” This date includes “updated studies and information from the Department of Energy’s 2025 Climate Work Group study that is currently being released for public comment.”&nbsp;That DOE <a href="https://www.energy.gov/sites/default/files/2025-07/DOE_Critical_Review_of_Impacts_of_GHG_Emissions_on_the_US_Climate_July_2025.pdf">report</a>, also released July 29, was authored by a group of five scientist assembled by Energy Secretary Chris Wright. “Among the key findings, the report concludes that CO2-induced warming appears to be less damaging economically than commonly believed, and that aggressive mitigation strategies may be misdirected,” the DOE said in a statement. “Additionally, the report finds that U.S. policy actions are expected to have undetectably small direct impacts on the global climate and any effects will emerge only with long delays.”The EPA’s Julu 29 proposal also aims to remove all GHG standards for light-, medium- and heavy-duty vehicles and heavy-duty engines, starting with EPA’s first GHG set in 2010 for light-duty vehicles and those set in 2011 for medium-duty vehicles and heavy-duty vehicles and engines. The EPA specified this includes off-cycle credits like the start-stop feature on most new cars.&nbsp;“As a result of these proposed changes, engine and vehicle manufacturers would no longer have any future obligations for the measurement, control, and reporting of GHG emissions for any highway engine and vehicle, including model years manufactured prior to this proposal,” the EPA said. “However, EPA intends to retain, without modification, regulations necessary for criteria pollutant and air toxic measurement and standards, Corporate Average Fuel Economy testing, and associated fuel economy labeling requirements.”The EPA in March 2025 announced its intent to reconsider the Endangerment Finding. With the release of the July 29 proposed rule, the regulatory process to officially repeal the Endangerment Finding is officially underway.A <a href="https://www.congress.gov/crs-product/LSB11320">report published by the Congressional Research Service</a> in June provides background on the 2009 Endangerment Finding and discusses legal considerations related to the EPA’s decision to revisit the finding. According to that report, any EPA final action to alter or not alter the Endangerment Finding will not only be subject to a public comment and rulemaking process, it will also be subject to judicial review. Because a revision or repeal of the Endangerment Finding would constitute a change in position, the report indicates the EPA would need to offer a reasoned explanation for its new approach. This would require the agency to address why it is disregarding the facts and circumstances that underlaid its original decision to issue the Endangerment Finding and subsequently reaffirm that action in later years, such as its 2016 rulemaking.&nbsp;According to the CRS report, it is also possible Congress could respond to EPA’s plan to rescind the Endangerment Finding. For example, Congress could nullify the finding, codify the finding, provide the EPA with specific statutory instruction on whether or how to regulate GHGs, or shape the EPA’s reconsideration process by altering procedural requirements or requiring EPA to weigh certain policy or economic considerations. Congress also has the power to overturn any final decision made by the EPA regarding the finding.A public comment period on the proposed rule will be open through Sept. 21. The EPA is scheduled to hold a public hearing on the proposal on Aug. 19-20. The hearing may be extended through Aug. 21, if necessary.&nbsp;Additional information, including a full copy of the proposed rule, is available on the EPA <a href="https://www.epa.gov/system/files/documents/2025-07/12744-01-oar-vehicle-rule-hearing-notice-nprm-20250729.pdf">website</a>.&nbsp;

2025-07-29 - EPA proposes to repeal 2009 Endangerment Finding, vehicle emission standards (4 publications)

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The U.S. EPA on July 29 released a proposed rule to repeal the agency’s 2009 Endangerment Finding, which forms the legal basis for the agency’s GHG regulations. The proposal also aims to repeal all GHG regulations for motor vehicles and engines.

EPA proposes to repeal 2009 Endangerment Finding, vehicle emission standards

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