Health, Environmental Groups Ask EPA to Reconsider Flawed, Unlawful Decision to Repeal the Endangerment Finding

(Washington, D.C. – April 16, 2026) Sixteen health and environmental groups have filed a petition with the U.S. Environmental Protection Agency outlining severe flaws in its rule to repeal the Endangerment Finding and motor vehicle climate pollution standards and describing how the Clean Air Act requires the agency to reconsider that damaging action.

The petition focuses on the repeal’s incorrect and unsupported claims that reducing climate pollution from U.S. cars and trucks is “futile.” It’s an especially flawed and problematic assertion given that these vehicles are the largest source of climate pollution in the U.S. and cause enormous economic and health harm and given the clear evidence that reducing this pollution will deliver substantial benefits to American families. 

The Endangerment Finding is EPA’s foundational 2009 determination that climate pollution is a danger to human health and well-being. It is based on a mountain of scientific evidence that has grown larger and more robust since then, and it underpins U.S. actions to reduce this harmful pollution.

Last year EPA proposed repealing the Endangerment Finding and motor vehicle climate pollution standards. During the public comment period, hundreds of thousands of people, businesses, and public health experts told EPA they were opposed to the action. In February, EPA Administrator Lee Zeldin finalized the repeal anyway. However, key aspects of the final rule are entirely new and were not in the proposal – so the public never had a chance to comment on them. The U.S. Clean Air Act guarantees the American people the right to review, address, and comment on the basis for this damaging decision that will lead to massive air pollution and health harms.

The petition includes extensive analysis and supporting documentation demonstrating that:

“If EPA had properly noticed these issues for public comment, commenters would have identified critical modeling flaws, analytical inconsistencies, unsupportable assumptions, and other objections to EPA’s analysis and methodologies.” (Petition, page 7)

Most notable is the completely new modeling and analysis conducted by EPA, after the public comment period, in order to support its cynical claim that reducing climate pollution from U.S. motor vehicles would be “futile.” EPA had made this flawed claim in its proposal, but relied on the findings of a widely discredited report that a federal court has since ruled was created illegally. In its final rule, EPA claims it is no longer using that unlawful report and is instead relying only on its new modeling.

The petition also identifies how EPA has:

• Systematically undervalued the benefits of reducing climate pollution from cars and trucks

The repeal assesses harms using only changes in global average sea level and temperature – measures that do not speak directly to the very real harms Americans are experiencing from vehicle climate emissions – and seeks to minimize and obscure those changes through its deeply flawed modeling. For example, EPA’s new analysis takes credit for emission reductions achieved by climate pollution standards over the past 15 years while simultaneously claiming those standards do nothing meaningful. EPA also arbitrarily chooses to divide those emissions in half, all to try to minimize emissions from the nation’s largest source of climate pollution.

• Concluded impacts of vehicle emissions are small by comparing them to phantom numbers and flawed metrics

EPA compares changes in temperature and sea level from regulating car and truck emissions to metrics that have nothing to do with harm – for instance, how precisely those changes can be measured. Some of the metrics EPA identifies to make this comparison do not appear anywhere in the sources the agency cites (Petition, page 35).  For others, EPA has made simple math errors that, once corrected, result in wildly different numbers – as much as 86% lower. (Petition, page 44).  As a result, EPA’s own analysis does not even support its conclusions. 

• Ignored clear and substantial health harms that EPA has long considered in all its actions

EPA claims for the first time in the final rule that, due to analytical uncertainties, it cannot monetize health benefits from reductions in toxic soot and smog pollution – even though it has done so for decades. In effect, that means EPA is claiming the health benefits of clean air are worth zero dollars. By “generically stating that costs are immense while casting aside any quantification, or even qualification, of health benefits, EPA has produced an egregiously skewed analysis.” (Petition, page 49)

Along with identifying these and other significant errors in EPA’s final rule, the petition includes analysis showing that climate pollution from cars and trucks is substantial and reducing it has enormous benefits – analysis that further supports extensive data submitted during the comment period on this issue.

The deficiencies in the final rule, as identified in the petition, are consistent with – and reinforce – the serious flaws throughout the Trump administration’s efforts to repeal the Endangerment Finding, including the rushed and secretive process and the strong evidence that Administrator Zeldin had prejudged the outcome of the rulemaking before it concluded.

EDF, NRDC (Natural Resources Defense Council), Union of Concerned Scientists, Earthjustice, Sierra Club, Clean Air Task Force, Environmental Law & Policy Center, Conservation Law Foundation, Public Citizen, Physicians for Social Responsibility, Clean Wisconsin, Clean Air Council, American Public Health Association, American Lung Association, Center for Biological Diversity, and Alliance of Nurses for Healthy Environments signed the petition. Many of those groups have already filed a lawsuit in the U.S. Court of Appeals for the D.C. Circuit challenging the repeal of the Endangerment Finding and vehicle emissions standards. The petition for administrative reconsideration is filed directly with EPA and is in addition to that lawsuit.

Read the petition and accompanying appendices here.

Environmental Defense Fund just released new interactive maps showing how climate change is already raising costs for families and how the administration’s attack on the Endangerment Finding will make that worse – including by increasing climate pollution by 18 billion tons, creating in $500 billion in health harms and forcing Americans to spend $1.4 trillion more on fuel. Read more here.

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