The Environmental Protection Agency has published a proposal to reconsider the agency's 2009 finding that greenhouse gases endanger public health and welfare. The agency is also proposing to repeal all GHG emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines to effectuate its reading of Clean Air Act (CAA) section 202(a).

This proposal includes repeal of the April 22, 2024 final rule from EPA that imposes the Phase 3 greenhouse-gas emission standards for heavy-duty vehicles. Those standards are more stringent than any prior standards and were projected to result in an increase in the production of electric heavy-duty vehicles to 45% of new vehicles by model year 2032.

The EPA asserts that the CAA does not authorize the EPA to prescribe emission standards to address global climate change concerns and, on that basis, 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. Alternatively, EPA proposes to rescind the Administrator's prior findings in 2009 because the EPA unreasonably analyzed the scientific record and because developments cast significant doubt on the reliability of the findings.

In addition, EPA proposes to repeal all GHG emission standards on the alternative bases 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.

On December 7, 2009, the EPA Administrator signed two distinct findings regarding greenhouse gases under section 202(a) of the Clean Air Act:

• Endangerment Finding: The Administrator finds that the current and projected concentrations of the six key well-mixed greenhouse gases—carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF₆)—in the atmosphere threaten the public health and welfare of current and future generations.

• Cause or Contribute Finding: The Administrator finds that the combined emissions of these well-mixed greenhouse gases from new motor vehicles and new motor vehicle engines contribute to the greenhouse gas pollution that threatens public health and welfare.

These findings do not themselves impose any requirements on industry or other entities. However, this action was a prerequisite for implementing greenhouse gas emissions standards for vehicles and other sectors.

Specifically. the Endangerment Finding is the legal prerequisite used by the Obama and Biden Administrations to regulate emissions from new motor vehicles and new motor vehicle engines. Without this finding, EPA would lack statutory authority under Section 202(a) of the CAA to prescribe standards for greenhouse gas emissions. EPA claims its proposal to rescind the finding, if finalized, would save Americans $54 billion in costs annually through the repeal of all greenhouse gas standards, including the Biden EPA's electric vehicle mandate, under conservative economic forecasts. 

EPA Administrator Zeldin announced that, if finalized, this proposal would remove all greenhouse gas standards for light-, medium- and heavy-duty vehicles and heavy-duty engines, starting with EPA's first greenhouse gas standards set in 2010 for light-duty vehicles and those set in 2011 for medium-duty vehicles and heavy-duty vehicles and engines. 

EPA's proposal also cites updated scientific data that challenge the assumptions behind the 2009 Endangerment Finding. Cited data includes the updated studies and information in the Department of Energy's 2025 Climate Work Group study that is concurrently being released for public comment.

The EPA announcement asserts that in the 16 years since the Endangerment Finding, the world has seen major developments in innovative technologies, science, economics, and mitigation strategies. EPA has never before now asked for public comment on the implications these developments have had on the Endangerment Finding. Additionally, major Supreme Court decisions in the intervening years have provided new guidance on how the agency should interpret statutes to discern Congressional intent and ensure that its regulations follow the law.

EPA has also scheduled a virtual public hearing on the recission of the Endangerment Finding and repeal of the GHG emissions standards. The hearing will be held August 19-20, 2025. Information on how to testify or register to view the hearing is available at the link.

NEFI will continue to follow these developments and inform its members of any determinations that may affect their businesses. For additional information please contact NEFI Regulatory Counsel Rick Schweitzer at rpschweitzer@rpslegal.com or (202) 223-3040.