A Legal Analysis of the Trump EPA’s Plan to Revoke the Endangerment Finding

The Trump Environmental Protection Agency (EPA) has issued a proposal to revoke the endangerment finding. The proposal relies on misinterpretations of the law and recent cases, fringe science, and tortured cost analysis to justify a conclusion that the EPA cannot and should not regulate greenhouse gases (GHG). Below, we explain the flaws in the agency’s reasoning.

What is the endangerment finding?

The “endangerment finding” is the EPA’s scientific and legal conclusion that the Clean Air Act requires regulation of greenhouse gas emissions to protect public health and welfare. The EPA issued the endangerment finding in 2009 pursuant to the Supreme Court’s decision in Massachusetts v. EPA.

What is the EPA’s reasoning for revoking the endangerment finding?

The proposal includes a grab bag of alternative reasons for revoking the endangerment finding. For example, it argues that the endangerment finding exceeded the agency’s statutory authority under section 202(a) of the Clean Air Act for many reasons. Its claims include:

• Arguing that the term “air pollution” in the Clean Air Act should be narrowly interpreted to only include air pollutants that cause harms through “local or regional exposure.” Under this novel reading of the Clean Air Act, the EPA cannot regulate any air pollutant on the basis that the pollutant causes global harm. This interpretation is inconsistent with the Supreme Court’s decision in Massachusetts v. EPA, which found that air pollutants that warm the global atmosphere are clearly “air pollutants” under the Clean Air Act.
• Arguing that the Court’s 2022 decision in West Virginia v. EPA imposes a new and higher “major question” bar to the Supreme Court’s prior conclusion that Congress gave the EPA the authority to regulate GHGs. But West Virginia v. EPA did not overrule Massachusetts v. EPA and it inherently acknowledged the EPA’s authority to regulate greenhouse gases.
• Arguing that the EPA does not have the discretion to issue a standalone endangerment finding separate from emissions standards to regulate that pollutant. This interpretation would require the EPA to make concurrent endangerment findings every time it issues emission standards for any pollutant based on its danger to public health and welfare. That would mean the EPA could never rely on its past findings about the danger of a given pollutant in order to issue new regulations concerning that pollutant.

Alternatively, the proposal argues that even if the EPA has the authority to address GHGs, the agency “exercised that authority unreasonably” in 2009. It does this largely by casting doubt on the scientific record. Among other things, the proposal:

• Argues that previous administrations did not consider the “potential benefits” of increased GHG concentrations, especially on plant growth and increased agricultural capacity.
• Argues that the reports from the U.N.’s Intergovernmental Panel on Climate Change (IPCC) and the U.S. Global Change Research Program (USGCRP) “are unduly pessimistic” about the effects of climate change and do not meet standards of President Trump’s “Restoring Gold Science” Executive Order.

Rejecting mainstream science in favor of fringe theories, the proposal argues that “there is insufficient reliable information to retain the conclusion that GHG emissions from new motor vehicles and engines in the United States cause or contribute to endangerment to public health and welfare in the form of global climate change.”

What is the new scientific data that the EPA is referencing? Is it reliable?

The proposal relies on a new Department of Energy (DOE) report on the impacts of carbon dioxide emissions on the U.S. climate. This analysis challenges the scientific consensus that increased carbon dioxide emissions will harm the environment by arguing that rising CO₂ emissions will actually result in “global greening” through increase in plant growth. The report was drafted by five contrarian scientists that include noted climate-science skeptics such as John Christy, Judith Curry, and Steven Koonin. Other scientists cited in the DOE report have claimed that DOE misused their findings.

The EPA has also halted work on the congressionally-mandated National Climate Assessment (NCA) that incorporates the expertise of over 400 scientists and has discounted the consensus of scientists around the world reflected in the NCA, the IPCC, and USGCRP.

DOE is accepting comments on the report through September 2, 2025.

What rules does the proposal impact?

In addition to rescinding the EPA’s 2009 endangerment finding, the proposal also seeks to rescind all GHG emission standards for new motor vehicles and engines. This rescission includes GHG emission standards for light-duty, medium-duty, and heavy-duty vehicles and engines for model years 2012 to 2027, and beyond.

What are the EPA’s reasons for repealing GHG emission standards for motor vehicles?

The Trump EPA first says that after revoking the endangerment finding, it no longer has any authority to issue GHG standards for vehicles. But the EPA also argues that even if courts rule that the endangerment finding must stand, the EPA can still repeal vehicles standards for GHG emissions because:

• Reducing GHG emissions from vehicles “would not measurably impact GHG concentrations in the atmosphere or the rate of global climate change.” According to the proposal, the EPA can only mandate vehicle engine designs that “remove GHGs already present in the atmosphere.” And there are no commercially available designs for such engines.
• Reducing and even eliminating GHG emissions from motor vehicles in the United States would be “futile” when it comes to stopping climate change.
• Regulations that shift the new vehicle market toward electric vehicles (EVs) would be analogous to the power plant regulations that the Supreme Court rejected in West Virginia v. EPA.
• Vehicle GHG pollution standards hurt the public more than climate change.

The proposal focuses on motor vehicles. How does it undercut the EPA’s ability to regulate emissions from power plants and other sources?

The 2009 endangerment finding was based on the EPA’s interpretation of section 202(a) of the Clean Air Act, which regulates the emissions of air pollutants from “new motor vehicles.” But after issuing that 2009 finding, the agency referred back to it when issuing regulations on GHG emissions from power plants and oil and gas facilities. Finalizing the current proposal would not repeal the power plant and oil and gas facility regulations but it would eliminate the basis for them. The EPA has already proposed a separate repeal of its GHG power plant regulations.

What isn’t changing under this proposal?

The EPA’s proposal does not change the reality of climate change and how it will affect our lives. The science of climate change has not changed, and the need for emission reductions remains just as important as it was before the EPA’s proposed repeal of the endangerment finding.

The EPA says it is not “at this time” revising vehicle emissions standards for pollutants other than GHGs, such as those for carbon monoxide, lead, and particulate matter. The agency is saying that it may revise those standards in a separate rulemaking.

As discussed above, this proposal would not repeal GHG standards for other sources such as power plants and oil and gas facilities. The EPA will need to conduct separate rulemakings to repeal those standard and it has already begun that process.

Who wins and who loses under this proposal?

The losers are the American people who will suffer from more heat and extreme weather events, more air pollution from fossil vehicles, and more delays in responding to the climate crisis.

The auto industry loses too: The rest of the world is rapidly shifting to EVs made by nations like China; slowing down that transition domestically hurts American automakers’ ability to compete in global markets. If U.S. automakers are going to remain competitive, they need the U.S. government to help spur innovation. With this announcement, the Trump administration has signaled that it won’t do that. This may be why major auto manufacturers did not cheer the proposal.

There’s only one winner: the fossil fuel industry. The companies that bankrolled President Trump’s campaign are getting what they paid for: regulations that delay a cleaner, cheaper, and more reliable future.

What does this mean for climate progress?

This proposal is just the Trump administration’s latest attempt to bail out the fossil fuel industry by gaslighting Americans about climate change. But renewable energy and clean vehicles are cheaper, healthier, and more reliable. Trump can slow them down, but he can’t stop them.

How can people weigh in on the proposed rule? Is this separate from other rulemakings?

The EPA will host virtual public hearings on the proposed rule on August 19-20, 2025. If there is a strong interest in commenting on the rule, the agency has stated that it will host an additional hearing on August 21.