Trump and EPA Administrator Lee Zeldin formalized the rescission of the 2009 endangerment finding on Thursday, effectively stripping the federal government of its legal authority to regulate greenhouse gas emissions from cars, trucks, power plants and industrial facilities.
The White House is calling it “the largest deregulatory action in American history.” Environmental groups are calling it something else entirely: the single biggest attack on federal climate action the country has ever seen.
Either way, the reverberations will be enormous, and the legal battles that follow could reshape environmental law for a generation.
What The Endangerment Finding Actually Was
To understand the magnitude of what just happened, you need to understand what was just torn up. The endangerment finding was a 2009 EPA determination, made during the Obama administration, that six greenhouse gases, including carbon dioxide and methane, pose a genuine threat to public health and welfare. That determination did not come out of thin air. It was a direct response to the Supreme Court’s landmark 2007 ruling in Massachusetts v. EPA, which established that greenhouse gases qualify as air pollutants under the Clean Air Act and that the EPA was obligated to regulate them if they were found to be dangerous.
The EPA reviewed the science, made the finding, and from that moment forward, the federal government had the legal foundation to regulate carbon emissions from vehicles, power plants, oil and gas operations, and more. It was the legal bedrock of virtually every major federal climate regulation for the past 17 years.
Now it is gone.
The Trump Administration’s Argument
The administration’s rationale is primarily legal, not scientific, and that distinction matters. The Trump EPA is not simply arguing that climate science is wrong (though the president has repeatedly called climate change a “hoax” and a “con job”). Instead, it argues that the Clean Air Act does not actually give the EPA authority to regulate greenhouse gases, and that the Obama-era EPA overstepped its bounds by establishing the finding in what the administration calls “a flawed and unorthodox way.”
White House press secretary Karoline Leavitt framed the move in pocketbook terms, claiming the rescission would save Americans $1.3 trillion, primarily through lower vehicle prices. The administration estimates average savings of more than $2,400 per new car, truck or SUV, since automakers will no longer need to meet the strict emissions standards that pushed them toward producing more expensive electric vehicles.
Zeldin, who first announced the EPA’s intention to eliminate the finding last March, has been characteristically blunt. “We are driving a dagger straight into the heart of the climate change religion,” he said at the time. On Thursday, he called it “the largest act of deregulation in the history of the United States.”
The Science The Administration Used, And What Scientists Think Of It
Here is where the story gets particularly uncomfortable for the Trump EPA. The scientific basis it used to justify the rescission came from the Department of Energy’s Climate Working Group, a panel of five researchers handpicked to produce a climate science review. That review prompted dozens of independent scientists to issue a joint rebuttal, calling it “biased, full of errors, and not fit to inform policymaking.” A federal judge ruled on January 30 that the Department of Energy violated the law when it created the group. The panel has since been disbanded.
Meanwhile, the National Academies of Sciences, Engineering and Medicine, the gold standard of scientific assessment in the United States, conducted its own review of the original 2009 finding. Its conclusion could not have been more direct: the finding was “accurate, has stood the test of time, and is now reinforced by even stronger evidence.”
The administration chose to lean on the discredited DOE report anyway.
What This Means For Cars, Trucks And The Auto Industry
The immediate fallout hits the transportation sector hardest. Transportation is the largest source of direct greenhouse gas emissions in the United States, and the endangerment finding was the legal basis for federal tailpipe emission standards that have pushed automakers toward cleaner vehicles for years.
With the finding revoked, the EPA will also propose a two-year delay to Biden-era rules restricting greenhouse gas emissions from cars and light trucks. The practical effect is that federal emissions standards for vehicles could effectively disappear, leaving a regulatory vacuum that many in the industry are actually dreading.
That is the irony at the heart of this story. Even the auto industry is split on whether this is a good idea. The Alliance for Automotive Innovation, representing most major manufacturers, has pushed for weaker standards. But they wanted weaker standards, not no standards. Eliminating the endangerment finding entirely could trigger a patchwork of state-by-state regulations, which is a nightmare scenario for companies that build vehicles for a national market.
And then there is Tesla. Elon Musk’s company, in a 27-page letter to the EPA last September, explicitly urged the administration to keep the endangerment finding in place. Tesla argued that the finding “is lawful, based on a robust factual and scientific record, and has been an established part of federal law for more than fifteen years.” The company warned that rescinding it would undermine billions in EV investments, create massive regulatory uncertainty, and hand a competitive advantage to Chinese automakers like BYD who are rapidly scaling their own EV production.
That Musk spent $300 million helping elect the president who just ignored his own company’s formal recommendation is one of those details that tells you everything you need to know about how Washington actually works.
The Legal Battle Is Already Here
Environmental groups are not wasting time. Earthjustice president Abigail Dillen called the move “a slap in the face to the millions of Americans who are living through climate disasters and their aftermath. And we will see this administration in court.” The Environmental Defense Fund, the Union of Concerned Scientists, and multiple state attorneys general are expected to file challenges.
They have history on their side. Courts have uniformly rejected legal challenges to the endangerment finding since it was established. The Supreme Court itself declined to hear an appeal as recently as 2023. The D.C. Circuit Court of Appeals upheld the finding that same year. And the underlying Supreme Court precedent in Massachusetts v. EPA remains the law of the land: greenhouse gases are air pollutants under the Clean Air Act.
The administration is betting that more recent Supreme Court decisions, particularly the 2022 West Virginia v. EPA ruling and the 2024 decision overturning Chevron deference, have shifted the legal landscape enough to sustain the rescission. Those cases limited what executive agencies can do without explicit congressional authorization, and the Trump EPA is arguing they warrant a reconsideration of the government’s entire approach to greenhouse gas regulation.
Legal experts are deeply skeptical. Cornell business professor John Tobin-de la Puente told CBS News he does not expect companies to make long-term plans based on the action, precisely because the legal foundations are so shaky. The procedural problems, including the tainted DOE science review and evidence that political appointees directed what was supposed to be an independent scientific process, give challengers additional ammunition.
The Bigger Picture
This is not happening in isolation. The world just experienced the three hottest years in recorded history. Americans are paying for the consequences of climate change in real time, through higher insurance premiums, disaster recovery costs, and agricultural losses. The U.S. has already withdrawn from the Paris Climate Agreement under Trump, and this latest move essentially dismantles the domestic regulatory architecture that existed to address the problem.
Senate Minority Leader Chuck Schumer called it “a corrupt giveaway to Big Oil, plain and simple.” Dr. Gretchen Goldman, CEO of the Union of Concerned Scientists, described it as “an obvious example of what happens when a corrupt administration and fossil fuel interests are allowed to run amok.”
The Trump administration sees it differently, of course. They frame the fight as one between economic freedom and regulatory overreach, between affordable energy and what Zeldin calls “the climate change religion.” The $1.3 trillion savings figure will be repeated constantly. The deeper costs, in health impacts, climate damages, and American competitiveness in a global economy that is moving toward clean energy with or without us, will be harder to quantify in a sound bite.
What is certain is that this will end up in court, probably within days. The legal fight over whether the federal government can simply decide that greenhouse gases are no longer dangerous, despite overwhelming scientific evidence and decades of judicial precedent saying otherwise, will be one of the most consequential environmental law battles of this century. The science has not changed. The politics have. And the courts will now decide which one matters more.