Trump to Rescind Landmark Climate Finding in Largest Deregulation Act in US History

WASHINGTON — The Trump administration will formalize on Thursday what it describes as the largest deregulatory action in American history by overturning the Obama-era scientific finding that carbon dioxide endangers human health, White House press secretary Karoline Leavitt announced Tuesday.

The move will rescind the 2009 "endangerment finding" that has served as the legal foundation for federal regulations on greenhouse gas emissions for more than 15 years, potentially eliminating the government's authority to regulate planet-heating pollution under the Clean Air Act.

"President Trump will be joined by EPA Administrator Lee Zeldin to formalize the rescission of the 2009 Obama-era endangerment finding," Leavitt told reporters at a press conference. "This will be the largest deregulatory action in American history."

The endangerment finding, established during the Obama administration, determined that carbon dioxide and other greenhouse gases threaten public health and welfare. This scientific conclusion provided the legal basis for regulating emissions from vehicles, power plants, and industrial facilities under existing environmental laws.

According to the White House, the rollback is expected to reduce costs for automakers by approximately $2,400 per vehicle. The administration formally proposed repealing the finding in July 2025, marking the most sweeping climate policy rollback to date.

Legal Challenges Expected

Environmental advocacy groups have already pledged to challenge the administration's action in court. Meredith Hankins, federal climate legal director at the Natural Resources Defense Council, called the rollback a "devastating blow to millions of Americans facing growing risks of unnatural disasters."

"The Trump EPA is cynically pretending climate change isn't a risk to Americans' health and welfare," Hankins said. "This is the biggest attack ever on federal authority to tackle the climate crisis. This isn't going to stand without a fight."

The Environmental Defense Fund and Earthjustice have also announced plans to sue the EPA over the rule. "We will see the Trump administration in court — and we are going to win," Hankins added.

Impact on Vehicle Emissions Rules

The repeal would eliminate the legal foundation for vehicle emissions standards introduced by the Biden administration in 2024, which aimed to cut passenger vehicle fleetwide tailpipe emissions by nearly 50% by 2032. The EPA had forecast that between 35% and 56% of new vehicles sold between 2030 and 2032 would need to be electric under those rules.

The Biden administration estimated that its emissions rules would generate net benefits of $99 billion annually through 2055, including $46 billion in reduced fuel costs and $16 billion in reduced maintenance expenses for drivers. Consumers were projected to save an average of $6,000 over the lifetime of new vehicles.

An EPA spokesperson defended the rollback, calling the endangerment finding "one of the most damaging decisions in modern history" and stating that "hardworking families and small businesses have paid the price" for regulations based on the finding.

President Trump signed an executive order on his first day back in office directing the EPA to assess whether the endangerment finding should be preserved. The finding has been used by both the Obama and Biden administrations to justify what Republicans characterize as trillions of dollars in greenhouse gas regulations covering vehicles, power plants, and industrial sources.