EPA Releases Proposal to Rescind Obama-Era Endangerment Finding

The U.S. Environmental Protection Agency (EPA) has proposed rescinding the 2009 Endangerment Finding, which currently serves as the legal basis for regulating greenhouse gas (GHG) emissions from new motor vehicles and engines under Section 202(a) of the Clean Air Act. If finalized, the proposal would remove all GHG emission standards for light-, medium-, and heavy-duty vehicles and heavy-duty engines, beginning with standards first established in 2010 for light-duty vehicles and 2011 for medium- and heavy-duty vehicles. This includes associated requirements such as off-cycle credit provisions. 

The EPA states that the proposal is informed by updated scientific data and recent judicial decisions clarifying the scope of EPA’s authority under the Clean Air Act. EPA also notes that technological and market changes since 2009 warrant reconsideration of the Endangerment Finding. The 2009 Endangerment Finding determined that six greenhouse gases, including carbon dioxide, contribute to air pollution that may endanger public health or welfare, thereby enabling EPA to set GHG emission standards for vehicles. This determination has underpinned multiple vehicle regulations issued since 2010. 

Section 202(a) directs EPA to set emission standards for new motor vehicles or engines if the Administrator determines that emissions of an air pollutant from these sources cause or contribute to air pollution that may reasonably be anticipated to endanger public health or welfare. The Endangerment Finding is a prerequisite for such standards. EPA is also reconsidering related regulations, including the Model Year 2027 and Later Light-Duty and Medium-Duty Vehicle standards and the Greenhouse Gas Emissions Standards for Heavy-Duty Vehicles. 

EPA has opened a public comment period on the proposal through September 22, 2025, with details published in the Federal Register and on the agency’s website. The agency is also concurrently releasing updated studies, including the Department of Energy’s 2025 Climate Work Group study, for public comment.