US President Donald Trump revoked a 2009 scientific finding that classified greenhouse gases as a threat to public health. The rule had formed the legal foundation for federal actions to reduce emissions from vehicles, power plants, and industry.
The White House described the move as the “largest deregulation in American history,” claiming it will lower vehicle costs by $2,400 and ease pressure on automakers. Environmental groups warned it represents the most significant climate rollback so far and promised to challenge it in court.
Trump attacks Obama-era climate measures
Speaking in the Oval Office, Trump called the 2009 finding “a disastrous policy that harmed the American auto industry and raised costs for consumers.” He labeled Democrats’ climate agenda a “radical scam” built on the rule.
Former President Barack Obama said repealing the rule leaves Americans less safe and less healthy. He argued the change primarily benefits the fossil fuel industry at public expense.
How the endangerment finding shaped federal climate policy
The Environmental Protection Agency first assessed greenhouse gases in 2009, declaring six major gases, including carbon dioxide and methane, dangerous to human health. With Congress unable to pass climate legislation, the finding became central to federal regulatory efforts.
Meghan Greenfield, former EPA attorney, said the rule governs emissions from vehicles, power plants, oil and gas production, landfills, and aircraft. “All standards across sectors rely on this single determination,” she explained.
Trump officials said the rollback could save over $1 trillion and lower energy and transport costs. They claimed automakers will save $2,400 per vehicle. Diana Furchtgott-Roth, formerly with the Department of Transportation, said regulations had pushed manufacturing overseas to dirtier production sites.
Environmental experts disputed the claims. Peter Zalzal from the Environmental Defense Fund warned Americans could face $1.4 trillion in additional fuel costs, 58,000 extra premature deaths, and 37 million more asthma attacks.
Effects on the auto industry
Automakers may face uncertainty as producing less fuel-efficient vehicles could reduce international sales. Climate law expert Michael Gerrard said the rollback enforces relaxed fuel economy standards but may reduce global demand for US cars.
Observers noted unintended consequences. The 2009 finding allowed federal authorities to block stricter state laws and climate-related nuisance lawsuits. Greenfield said the rule had prevented many cases and predicted new legal challenges from states and nonprofits.
Scientific controversy
The Department of Energy formed a panel last year questioning widely accepted science on greenhouse gas warming. That report guided the proposal to overturn the 2009 finding. Many experts criticized the panel as biased and unrepresentative.
A federal judge ruled the department violated the law in forming the panel. Legal analysts said the administration may seek a Supreme Court review. If successful, the repeal could become permanent, preventing future presidents from reinstating the rule without Congress.
Greenfield said, “The EPA is leaving this space entirely. A Supreme Court ruling would block any future president from reversing this decision.”

