Removing the Earth Under Our Feet: The Elimination of the GHG Endangerment Finding

I. Introduction
Climate change, an environmental and societal issue, is more than ever a topic of global importance. To mitigate the effects of the changing climate, several countries have implemented progressive policies to reduce global greenhouse gas (GHG) emissions. President Trump’s reelection greatly impacted climate policy, especially with the second withdrawal from the Paris Agreement.[1] This administration’s disregard for the climate crisis became even clearer when they initiated the cancellation of many tax credits imposed by the 2022 Inflation Reduction Act through the passage of the One Big Beautiful Bill Act.[2] Through these changes, the IRA will no longer aid in subsidizing and promoting renewable energy targets for the United States.[3] This string of climate setbacks raises concerns about what some consider the biggest blow to climate regulations in the United States—the repeal of the Endangerment Finding. The Endangerment Finding, in its simplest form, designates a select few GHGs as harmful to the environment. Established in 2009, it allows the Environmental Protection Agency (EPA) to create regulations that limit greenhouse gas emissions for public and environmental health. With various justifications from the Trump administration’s EPA and legal action from several states and organizations, the fate of the Endangerment Finding within the United States’ climate policy remains ambiguous.

II. The Influence of the Endangerment Finding
Kickstarted by Massachusetts v. EPA (2007), the Supreme Court ruled that the EPA must establish an endangerment finding outlining evidence supporting GHGs as pollutants that harm public health and welfare.[4] The Massachusetts v. The EPA case involved many states and organizations challenging the EPA’s claim that it could not regulate GHG emissions under the Clean Air Act (CAA). The Supreme Court ruled that the EPA has the authority to regulate GHG emissions because they lie within the CAA’s definition of an air pollutant. Additionally, they ruled that the EPA is required to regulate pollutants if they are harmful to public health or welfare, even if not explicitly listed in the CAA.[5] Therefore, Massachusetts v. EPA established the grounds for the Endangerment Finding.

The Endangerment Finding defines six different GHGs as harmful pollutants: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. Based on this finding, the EPA established that greenhouse gas emissions released from transportation vehicles negatively impact public health. This resulted in regulations that significantly cut GHG emissions from transportation vehicles.[6] In 2015, the same Endangerment Finding was used to establish regulations for emissions from fossil-fueled electric utility generating units, or power plants.[7] More recently, in 2021, regulations on emissions from airplanes and airplane engines were set.[8] Many critics claimed that a new Endangerment Finding should have been established for new regulations to be set forth. However, the EPA argued that a new finding was not necessary as the same pollutants were being regulated in the latter regulations. The criticism that the Endangerment Finding was being used too broadly was put to rest as the EPA continued to stand firm in the original 2009 Endangerment Finding being used to regulate the same pollutants.[9]

In the past 16 years, the Endangerment Finding has served an important role in regulating United States GHG emissions and mitigating the impacts of climate change. Since its inception,  additional scientific evidence and support have indicated further dangers caused by the six pollutants outlined in the original finding. In the 2012 case before the U.S Court of Appeals for the D.C. Circuit, Coalition for Responsible Regulation v. EPA, the Endangerment Finding was further upheld when challenged for its use in regulating tailpipe emissions.[10] The court concluded in its official decision “that the Endangerment Finding is consistent with Massachusetts v. EPA and the text and structure of the CAA, and is adequately supported by the administrative record.”[11] In addition, the most recent reports from the Intergovernmental Panel on Climate Change have further established the worldwide impact of GHGs. Greenhouse gas emissions are directly linked to severe weather events, disrupting food production, and increasing transmission of diseases.[12] Due to the regulations on car engines, power plants, and other GHGs, the potential of these harmful stressors on public welfare have been reduced in synchrony with emissions.[13] Therefore, the Endangerment Finding was a crucial step in the right direction for improving both environmental and public health on the national level.

III. The Largest Deregulatory Action in United States History
On February 12, 2026, the Trump Administration, along with the EPA administrator Lee Zeldin, announced the repeal of the 2009 Endangerment Finding.[14] Lee Zeldin announced the repeal, claiming “the Trump EPA is strictly following the letter of the law, returning commonsense to policy, delivering consumer choice to Americans and advancing the American Dream”. The repeal takes the form of an EPA rule, declaring that Section 202(a) of the CAA does not authorize the regulation of GHG emissions, directly conflicting with Massachusetts v. EPA. Therefore, the repeal suggests that the administration of the GHG regulations is not subject to the EPA’s interpretation of the CAA, and instead requires congressional legislation.[15] The Trump Administration believes that because the Endangerment Finding greatly influences policy and the economy, Congress should do its duty to pass legislation rather than giving control to the EPA. The repeal of the Endangerment Finding is the largest deregulatory action in United States history.

The official press release by the EPA explains the repeal is in the best interest of the United States and its people.[16] The EPA argues that the original basis for regarding GHG emissions as harmful to human health is incorrect. Based on modelling efforts, the EPA details that eliminating GHG emissions from vehicles would have no material impact on the global climate through 2100.[17] Because of this, the Endangerment Finding is unnecessary for the EPA to regulate. The EPA maintains that the repeal of this finding does not affect the regulation of pollutants that are deemed actually toxic or harmful, such as ozone, carbon monoxide, and nitrous oxides.[18]

In addition to claiming that GHG emissions have minimal environmental impact, the EPA argues that the Endangerment Finding harms taxpayers, vehicle owners, businesses, and consumers. The Trump EPA estimates $1.3 trillion in savings for American families from the regulations imposed by the Endangerment Finding.[19] Before the repeal, this large financial stressor was enforced on Americans in the form of increased vehicle costs, limiting the accessibility of purchasing vehicles for the average American. Without these regulations, increasing vehicle costs will make it more difficult for consumers and businesses to purchase vehicles for travelling to work, healthcare transportation, and other essential daily functions. The repeal also intends to uphold consumer choice. Several policies that cite the Endangerment Finding “push” electric vehicle mandates, off-cycle credits, and other vehicle attributes that reduce emissions. The Trump EPA argues that these “pushes” limit consumer choice, and the repeal will allow Americans and businesses to purchase whichever vehicle they choose.

To comply with the rulemaking process, the EPA collected public opinion on the repeal of the Endangerment Finding. During the public comment period, over 600 people testified, and approximately 572,000 public comments were made. The EPA states that the commenting period resulted in substantial changes to the final rule of repeal.[20] These extensive comments addressed the legal framework for the repeal, the shift in analysis of the CAA, the retrospective nature of the repeal, and scientific basis for policy decisions.[21] The response to many of these comments supported the EPA’s decision to repeal the Endangerment Finding, disagreeing with the arguments set forth. A specific group of commenters claimed that a change in administration should not result in a change of analysis for regulations, directly challenging the Trump EPA’s justifications for the shift. The EPA responded by claiming the shift was not due to a change of administration and rather the repeal was part of the constitutional democratic process.[22]

IV. Legal Action: Success or Failure for Future Regulations
Several states, cities, and environmental groups responded to the repeal of the Endangerment Finding with legal action. Leading groups in Massachusetts, New York, Connecticut, and California filed a lawsuit in the U.S. Court of Appeals arguing that the repeal was illegal.[23] The lawsuit is grounded in the scientific evidence of the dangers that GHG emissions pose to human health and the climate crisis. Simply, the coalition is bringing this lawsuit forward to protect at-risk communities, public health, and environmental health. 

The lawsuit is likely to garner success in lower courts; strong evidence has been presented in the lawsuit, and it is connected to the Massachusetts v. EPA decision. The strength comes from the support of a Supreme Court case that has faced unsuccessful challenges as well as scientific evidence mentioned previously, to oppose the Trump EPA’s modelling data. However, legal scholars expect the Trump administration to bring the lawsuit to the Supreme Court, likely leading to an overturn. The current Supreme Court maintains  a conservative majority, suggesting that a complete overturn of Massachusetts v. EPA is likely.[24] This would massively undermine any further attempts to attack the repeal of the Endangerment Finding. It is also important to note that if the repeal is not successfully challenged, it will be nearly impossible for later administrations to reinstate another Endangerment Finding. The CAA could no longer be used as a justification for regulating GHG emissions as it was originally. Therefore, the lawsuit stands to either reinstate the Endangerment Finding or possibly prohibit its implementation in future regulatory attempts.

V. The Future of Emissions Regulations: Uncertainty
Uncertain legal decisions will shape the future of the Endangerment Finding. The repeal places the responsibility of regulating GHG emissions in the hands of Congress rather than the EPA. This process is much more complex and difficult compared to the rulemaking that the EPA previously had the authority to conduct.[25] Either way, the uncertainty of the repeal regarding the success or failure of legal action leaves Americans and those impacted by the regulations in a state of irresolution.

Despite the fluctuating state of the Endangerment Finding regulations, there are several pathways for GHG emissions mitigation in the United States today. Even after the EPA began regulating GHG emissions, several states enacted additional restrictions on emissions to reduce public and environmental health impacts. Approximately 24 states have policies regarding emissions.[26] These policies include GHG emission targets, climate action plans, carbon pricing, electricity standards, and transportation. These policies allow states to tailor their regulations to their specific needs, further developing the future of policy design.[27] Admittedly, a set standard for emission regulations across the United States would serve to fight the climate crisis more directly, but action is still possible since repeal does not withdraw all GHG emission policies in the United States.[28]

Beyond strict emissions mitigation, a variety of policies could be implemented to reduce GHG emissions. There has been more movement towards renewable energy production in the United States over the past several years, and the climate movement has grown stronger and stronger. It is important to note that, although the Endangerment Finding was landmark legislation for climate regulations, it is not the last hope for positive climate progress. The uncertainty around the repeal presents hope that these potential issues will never come to pass. In addition, focus can be put toward building bipartisan support within Congress to achieve much-needed GHG emissions regulations.

VI. Conclusion
The repeal of the Endangerment Finding is concerning for the future of greenhouse gas emissions regulations in the United States. What was once considered the hallmark of climate change is no longer considered harmful to public health by the Environmental Protection Agency. The Trump administration frames the repeal as boosting the United States economy and increasing both vehicle accessibility and consumer choice. However, there is significant uncertainty about the outcome of legal action from several states and organizations. These problems would be alleviated by reinstating the Endangerment Finding, if the repeal is found to be illegal. Alternatively, the Supreme Court case that instituted the legal basis for the Endangerment Finding, Massachusetts v. EPA, could be overturned, preventing future administrations from reinstating the finding. While the outcome is uncertain, there is still hope and other avenues for supporting climate-positive actions. Within the context of other climate drawbacks, the repeal of the Endangerment Finding is without a doubt a massive blow to climate policy in the United States.

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[1] Amnesty Int’l, Global: US Withdrawal from Landmark Paris Climate Agreement Threatens “a Race to the Bottom”.

[2] Hagai Zaifman, John T. Schaff, Angela T. Richards, Kenneth W. Irvin, Tara Higgins & Michael E. Borden, The “One Big Beautiful Bill” Act – Navigating the New Energy Landscape, Sidley Austin LL.

[3] Olivia Guarna & Amy Turner, 100 Days of Trump 2.0: The Inflation Reduction Act, Climate L. Blog.

[4] Stanford Woods Inst. for the Env’t, EPA Endangerment Finding Explained: 5 Facts About Science and Health Risks.

[5] Sabin Ctr. for Climate Change L., Massachusetts v. EPA (Apr. 2, 2007).

[6] Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act, 74 Fed. Reg. 66,496 (Dec. 15, 2009).

[7]Ibid.

[8]Ibid.

[9]Ibid.

[10] Jessica Wentz, Attribution Science and EPA’s Reconsideration of the GHG Endangerment Finding, Climate L. Blog (May 22, 2025).

[11]Coal. for Responsible Regulation, Inc. v. EPA, 684 F.3d 102 (D.C. Cir. 2012).

[12] World Health Org., Climate Change and Health (Oct. 12, 2023).

[13] Harvard T.H. Chan Sch. of Pub. Health, Why the Endangerment Finding Mattered So Much for Health and the Climate.

[14] Federal Register, supra note 6.

[15] Scott Novak & Allison Watkins Mallick, 9 Questions About EPA’s Rescission of the 2009 Endangerment Finding, Baker Botts (Feb. 13, 2026).

[16] U.S. Env’t Prot. Agency, President Trump and Administraimposed on Americans in the form of higher vehicle costs, limiting the average American's ability to purchase a vehicletor Zeldin Deliver Single Largest Deregulatory Action in U.S. History (Feb. 12, 2026).

[17]Ibid.

[18] U.S. Env’t Prot. Agency, NAAQS Table.

[19] EPA, supra note 16.  

[20]Ibid.

[21] U.S. Env’t Prot. Agency, Reconsideration of 2009 Endangerment Finding and Greenhouse Gas Vehicle Standards: Response to Comments, EPA Doc. No. P101HV15.

[22]Ibid.

[23] Lisa Friedman, States Sue EPA Over Plan to Repeal Endangerment Finding, N.Y. Times.

[24] Carbon Brief, Q&A: What Does Trump’s Repeal of US Endangerment Finding Mean for Climate Action?.

[25] Jody Freeman, Beyond “Endangerment”: Finding a Way Forward for U.S. Climate Policy, Yale Env’t 360.

[26] Ctr. for Climate & Energy Sols., State Climate Policy.

[27] Ibid.

[28] Freeman, supra note 25.