EPA Proposes to Revoke Endangerment Finding — What’s at Stake?

The U.S. Environmental Protection Agency (EPA) has proposed to revoke its 2009 Endangerment Finding, which underpins the regulation of greenhouse gas (GHG) emissions from cars, trucks, and engines.

If finalized, this would mean:

• Repeal of all federal GHG standards for light-, medium-, and heavy-duty vehicles.

• GHGs* would no longer be treated as pollutants under the Clean Air Act, and therefore not eligible for tailpipe limits.

• CO₂-related compliance credits and reporting obligations would end.

This move would NOT affect current criteria pollutant standards (like Tier 3 NOₓ or PM) or NHTSA fuel economy standards (although these are being reviewed separately).

The move creates major legal and regulatory uncertainty for automakers and clean energy efforts, given that technology investments are made with a several-year horizon. Expect legal battles to come, this one is going to be messy.

*Six long-lived and directly-emitted greenhouse gases were identified in the 2009 endangerment finding: CO₂, N₂O, CH₄, hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6).

📅 EPA is now accepting public comments through September 21, 2025.