President Donald Trump announced Thursday that his administration has revoked the Environmental Protection Agency’s (EPA) 2009 endangerment finding, a decision that eliminated the legal foundation for U.S. regulations targeting greenhouse gas emissions under the Clean Air Act.
The endangerment finding, issued during the Obama administration, determined that carbon dioxide and other greenhouse gases pose a threat to public health and welfare. It has since served as the legal basis for a wide range of climate regulations, including emissions limits for cars, trucks, power plants, and industrial facilities.
Trump called the move “the single largest deregulatory action in American history, by far.” EPA Administrator Lee Zeldin said the finding had enabled excessive federal regulation, describing it as “the Holy Grail of federal regulatory overreach.”
“The endangerment finding was one of the greatest scams in history,” Trump said at a White House event. “It had no basis in fact or law. Fossil fuels have saved millions of lives and lifted billions out of poverty.”
Legal experts expect the decision to face significant court challenges. Ann Carlson, professor of environmental law at the University of California, Los Angeles, said reversing the finding could have broader impacts than previous regulatory rollbacks and could remove the legal justification for many climate rules.
The Supreme Court ruled in 2007 that greenhouse gases qualify as pollutants under the Clean Air Act, and courts have since upheld the 2009 endangerment finding, including a 2023 decision by the U.S. Court of Appeals for the District of Columbia Circuit.
Environmental organizations said the repeal undermines the federal government’s ability to address climate change. Gina McCarthy, former EPA administrator and climate adviser in the Biden administration, called the move reckless, saying the EPA is prioritizing industry interests over public health.
The Trump administration also proposed delaying by two years a Biden-era rule limiting greenhouse gas emissions from cars and light trucks. Zeldin said the delay would allow the agency to adjust rules in response to slower electric vehicle sales, while promoting consumer choice and reducing costs.
The EPA will also end tax credits for automakers installing automatic start-stop systems, designed to cut emissions. Zeldin said, “Everyone hates” the feature.
Transportation Secretary Sean Duffy and Zeldin have moved to reverse mileage standards imposed under President Joe Biden. Trump said loosening these rules would lower new car costs and improve access to gasoline-powered vehicles.
Critics warned that the changes will prolong the presence of emitting vehicles and limit protections against climate-related health impacts. Dr. Lisa Patel of the Medical Society Consortium on Climate and Health said repealing the finding would increase pollution-related health issues, especially among children.
David Doniger of the Natural Resources Defense Council said the action could invalidate most U.S. climate regulations and prevent future administrations from instituting new rules.
Conservative groups and some Republican lawmakers have long criticized the endangerment finding, arguing it led to economically damaging rules. Myron Ebell, a conservative advocate, said repealing it is “the most important step taken by the Trump administration so far to return to energy and economic sanity.”
