The EPA is expected to formally propose rolling back the 2009 "endangerment finding," the scientific and legal foundation for all U.S. climate regulations under the Clean Air Act. This unprecedented move, pursued for years by right-wing groups, would create major legal and regulatory uncertainty for industries and trigger a lengthy court battle likely to reach the Supreme Court.
Critics argue the administration's draft proposal uses a wide array of scientifically and legally dubious arguments to undermine the finding, including questioning whether global greenhouse gases can be regulated under the Clean Air Act. The original finding, mandated by a 2007 Supreme Court ruling, has endured because many industries valued the regulatory stability and level playing field it provided.
Main topics: EPA endangerment finding rollback, legal and regulatory consequences, political and industry reactions, historical context of the finding.
On Thursday, the Environmental Protection Agency is expected to roll back the endangerment finding, which underpins the US’s ability to regulate the greenhouse gases that cause climate change. The rollback, the result of more than 15 years of work from right-wing special interest groups, represents the most aggressive move against climate regulation in the US to date—and will introduce a lengthy fight that’s almost certain to wind up in front of the Supreme Court.
The move could also create significant legal and regulatory uncertainty for a wide swath of industries, from oil companies fighting state and local climate lawsuits to car companies attempting to plan production of new models in the midst of an ongoing legal fight.
“I don't see any plan, any strategy, any end game,” says Pat Parenteau, a professor of environmental law at Vermont Law and Graduate School. “I don't see anything from this administration, just fuck everything up as much as you can. You can print that.”
The Clean Air Act mandates that the EPA regulate any type of air pollution that might constitute a hazard to public health and welfare. The endangerment finding is a 2009 ruling that creates a scientific and legal basis for regulating greenhouse gases under the Clean Air Act. This finding is the bedrock for every climate-based regulation the agency has issued since, from restrictions on power plants to emissions standards for cars.
The original finding was mandated by a 2007 Supreme Court decision, Massachusetts v. EPA, in a case brought by the state against the Bush administration, challenging it for not taking action to regulate greenhouse gas emissions from vehicles. The Supreme Court ruled that greenhouse gases should be regulated under the Clean Air Act.
Even before the endangerment finding officially came into existence, it was already a political football for right-wing interests. Following the Supreme Court decision, the Bush-era EPA sent an email to the White House linking six greenhouse gases to climate change and detailing a number of disparate impacts on public health and the environment. However, the White House refused to open the email to acknowledge the science and the finding, kicking the can down the road for nearly two years until the email was released in 2009 under the Obama administration. Right-wing groups, including the Heritage Foundation, the group behind the Project 2025 plan, have been vocal critics of the ruling and the EPA’s actions on greenhouse gases for nearly two decades. (As The New York Times reported on Monday, the Heritage Foundation funded a campaign in 2022 to help create regulatory documents that enabled the repeal of the endangerment finding.)
The endangerment finding has proven remarkably difficult for these groups to attack. Both of Trump’s first EPA administrators declined to challenge the finding while they were in office, despite pressure from ideologues inside and out of that administration.
This hesitancy was thanks in part to businesses supporting the original EPA ruling. “Industry has generally been in favor of stability in this space and having EPA maintain its regulatory authority,” says Meghan Greenfield, a former senior counsel at the EPA. “The endangerment finding serves this really important purpose in providing a level playing field and acknowledging EPA's authority.”
A draft version of the rollback released this summer contained a myriad of arguments aimed at undermining the finding, including making the case that because greenhouse gas emissions are global, they should not be regulated under the Clean Air Act.
“The proposal pretty much threw spaghetti on the wall,” says Rachel Cleetus, a senior policy director at the Union of Concerned Scientists. “There's just all kinds of arguments, all of them without merit—Clean Air Act arguments, science arguments, cost arguments.”
The draft rollback also attempted to attack the climate science underpinning the endangerment finding, using a report produced by the Department of Energy and authored by five known climate contrarians over the course of a few months. As WIRED reported, many scientists whose research was cited in the DOE report felt that their work was misused or misconstrued to make bad arguments about climate science. These scientific arguments, experts say, will also be particularly vulnerable if taken before a court—particularly since a judge ruled last month that the group that authored the report was put together illegally.
“I will eat my car if they get upheld on the science,” says Parenteau.
The rollback has not met with resounding support from many of the industries that it would directly affect. Over the past decade, oil majors have begun to face a wave of lawsuits from cities, states, and municipalities holding them accountable for climate damages incurred from extreme weather. A bedrock foundation of the industry’s defense against these lawsuits, ironically, lies in the EPA’s authority to regulate greenhouse gases: Oil companies have argued that states and cities cannot take them to court over climate change, given that the federal government controls climate regulation under the Clean Air Act. (The American Petroleum Institute, the leading lobby group for the oil and gas industry, has asked the EPA to clarify that the rollback of the endangerment finding would apply only to tailpipe emissions from cars, leaving stationary sources like power plants technically protected by the rule.) Meanwhile, car and truck producers have expressed concern about how they can plan manufacturing timelines in an uncertain regulatory environment, according to an analysis of public comments on the endangerment finding rollback done by InfluenceMap, a group that tracks lobbying.
But the Trump administration has proven time and again that ideology, not creating stable business environments, guides many of its major decisions. (On Wednesday, just a day before the EPA’s rollback, President Trump signed an executive order mandating that the Department of Defense buy electricity from coal-fired power plants, his latest bid to save the dying industry.) The administration has already done away with multiple regulations, effectively kneecapping greenhouse gas regulation. Challenging the endangerment finding is not a practical step forward meant to benefit industry or create meaningful policy changes, but rather an attack on the Massachusetts v. EPA decision itself.
It’s guaranteed that several environmental groups will immediately launch a challenge to the EPA’s new rule. Legal experts tell WIRED that it’s also clear that the EPA is seeking to take this struggle directly to the Supreme Court. Usually, Greenfield explains, complex rules like the one the EPA will propose take a few years to finalize. The rush to introduce the endangerment finding rollback—which happened in a matter of months—shows the administration’s eagerness to litigate the issue as fast as possible.
“If you're going to spend time and effort doing something that you think is important, you want to kind of hold the White House while it’s being defended through the end,” she says. “We’re only a year into the administration. I think it is fair to say that this has just, objectively, been done extremely quickly.”
If the Supreme Court overturns Massachussets v. EPA, it could effectively remove the ability for the EPA to regulate greenhouse gas emissions at all, turning that task over to a divided Congress.
“If they succeed [at the Supreme Court], even the next president couldn't undo it,” says Michael Gerrard, a professor at Columbia Law School and the director of that school’s Sabin Center for Climate Change Law.
Overturning Massachusetts v. EPA would be such a monumental disruption of modern environmental law that some experts think it’s not a possibility, even with a conservative supermajority.
“I don't think they get the Supreme Court agreeing that EPA has no authority, none, nada, to regulate greenhouse gas emissions under the Clean Air Act,” says Parenteau. “If that happens—I don’t know what else I’ll eat, but there’s something else I’ll eat.”
Update: 2/13/2026, 10 AM EDT: This story has been updated to correctly reflect Pat Parenteau's professional affiliation.
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