California leads 25-state coalition to sue EPA over vehicle "endangerment finding" rescission

California Attorney General Rob Bonta announced that California is co‑leading a coalition of 25 attorneys general and one governor to challenge the Trump administration and the Environmental Protection Agency's decision to rescind the federal "endangerment finding," the state official said at a press conference.

"We're challenging the Trump administration's unlawful decision to roll back one of the most important climate protections in our country," Bonta said, arguing the endangerment finding has been the legal foundation for vehicle pollution limits for 15 years and is grounded in science.

The announcement brought comments from California Air Resources Board Chair Lauren Sanchez, who called the rescission "a direct threat to the safety and well‑being of every American," and said California will defend its authority under state law. "When Washington DC steps away from its responsibility, California steps forward," Sanchez said.

Governor Gavin Newsom framed the move as part of a broader attack on climate science and public health, citing recent heat waves and wildfire smoke as examples of harms state action is intended to address. "Pollution is an act of theft," Newsom said, arguing state policies have reduced emissions while growing the economy.

Speakers emphasized that the endangerment finding — the federal determination that greenhouse gas emissions from vehicles endanger public health and welfare — underpins federal regulation under the Clean Air Act and has been relied on by administrations and courts for years. Bonta said the administration's rescission lacks credible science and that the coalition will take the matter to court: "So we'll see the Trump administration in court again."

CARB officials reiterated that California's authority under AB 32 to regulate greenhouse gas emissions remains unchanged and that the state will continue its programs, including amendments to the cap‑and‑invest framework to balance ambition and affordability. Sanchez noted ongoing stakeholder engagement on staff proposals and referenced prior litigation defending California's waiver and vehicle standards.

The officials answered questions on the economic and insurance impacts of climate risk and said state action and litigation are part of protecting public health and the economy. The press conference concluded with the coalition's stated intent to proceed with legal action challenging the EPA's rescission.

Next steps: officials said they will litigate the rescission in federal court; no court filing date or docket number was provided during the event.