Twenty-four states, ten cities, and five counties filed suit in federal court this week, challenging the Trump administration’s repeal of the 2009 EPA endangerment finding — the legal foundation for all greenhouse gas regulation under the Clean Air Act.
Without it, no federal authority exists to limit emissions from cars, power plants, or oil and gas facilities.
In February 2026, the Trump administration overturned the EPA’s “endangerment finding,” a legal cornerstone of federal climate regulation that has underpinned EPA climate policy, reflecting the agency’s conclusion that greenhouse gases pose a threat to human health since 2009. The suit follows an earlier challenge by environmental and public health groups last month.
EPA Administrator Lee Zeldin defended the rescission, with EPA stating “Affordable, reliable electricity is key to the American dream and a natural byproduct of national energy dominance.”
Based on EPA’s estimates, this proposal would save the power sector $19 billion in regulatory costs over two decades beginning in 2026, or about $1.2 billion a year. However, fact-checkers found the figure counts only costs, never benefits — and one of the EPA’s own internal analyses shows the rollback could cost Americans $180 billion on net once higher gas prices are factored in.
EPA’s action in rescinding the endangerment finding is controversial and it will be subject to vigorous legal challenges. Numerous states and environmental organizations have already declared that the move was illegal and have stated their intention to challenge it in court.
The legal process — which should begin in the U.S. Court of Appeals for the D.C. Circuit and may ultimately include a decision by the U.S. Supreme Court — will probably take many years, and indeed a final determination on the legality of EPA’s action may not be made until the Trump Administration leaves office in January 2029.