On 12 February 2026, US Environmental Protection Agency (EPA) Administrator Lee Zeldin announced one of the largest deregulatory actions in US history. EPA will eliminate the 2009 Greenhouse Gas (GHG) Endangerment Finding (Endangerment Finding) and all subsequent federal GHG emission standards for all vehicles and engines of model years 2012 and beyond. This action also eliminates all off-cycle credits, including for the start-stop feature. The final rule will almost certainly trigger a series of legal challenges.

Background

Under Section 202(a)(1) of the Clean Air Act (CAA), EPA is tasked with prescribing emission standards for new motor vehicles and engines when the administrator determines that emissions from new motor vehicles and engines cause air pollution that may endanger public health or welfare. In the past, “air pollution” under the CAA meant pollution that harms health or the environment through local and regional exposure. In a novel approach, the Obama-Biden administration accessed EPA’s authority to regulate automobiles for contributing to GHG concentrations. 

Because of the Endangerment Finding, the vehicle industry was pressured to phase down production of various models of traditional gasoline and diesel trucks and reengineer towards electric technologies. The Endangerment Finding also supported off-cycle credits to incentivize automakers into meeting federal GHG standards on paper, by adding features like the start-stop feature. EPA now asserts that its experts have found there was no material benefit to complying with these GHG regulations. 

Recently, US Supreme Court decisions in Loper Bright Enterprises v. Raimondo (2025), West Virginia v. EPA (2024), and Utility Air Regulatory Group v. EPA (2014), have provided significant new analysis and interpretation of the authority of executive branch agencies, including clarifying the scope of EPA’s authority under the CAA, likely making the broad interpretation of “air pollution” under the Obama-Biden administration unlawful. These decisions emphasized that statutes have a meaning fixed at the time of enactment, and policy determinations must be made by Congress, not administrative agencies.

EPA’s Evaluation

EPA considered and reevaluated the legal foundation of the Endangerment Finding and the text of the CAA in light of these recent court decisions. EPA concluded that Section 202(a) of the CAA does not provide statutory authority for EPA to prescribe motor vehicle and engine emission standards in the manner utilized, including for the purpose of addressing global climate change. Therefore, EPA believes there is no legal basis for the Endangerment Finding and resulting regulations. 

EPA now finds that even if the United States were to eliminate all GHG emissions from all vehicles, there would be no material impact on global climate indicators through 2100. Therefore, maintaining GHG emission standards is not necessary for EPA to fulfill its core mission of protecting human health and the environment. Additionally, they found it is not within the authority Congress entrusted to EPA.  

EPA conducted a 52-day public comment period, including four days of virtual public hearings where more than 600 individuals testified. EPA received about 572,000 public comments on the proposed rule and made updates to the final rule in response to the comments. A summary of public input and EPA’s responses to all comments can be found in the final rule preamble and accompanying documents, and all comments received, including entries summarizing several hundred mail campaigns, are available in the rulemaking docket.

Effect of the Deregulation

EPA estimates that the final rule will save Americans over US$1.3 trillion by removing the regulatory requirements to measure, report, certify, and comply with federal GHG emission standards for motor vehicles, and repeals associated with compliance programs, credit provisions, and reporting obligations that exist to support the vehicle GHG regulatory regime. EPA’s decision intends to make vehicles more affordable for American families and decrease the cost of living on all products by lowering the costs of trucks.  

The Supreme Court ruled in 2007 that the EPA had the authority to regulate heat-trapping GHGs. However, the Supreme Court’s more recent decisions—including Loper Bright—direct authority for policy determinations back to Congress, deemphasizing administrative agencies’ role in this process. EPA’s new rule also shows a commitment to avoiding a progressive approach to environmental statutes’ meaning over time. Rather, these statutes will be applied according to their meaning at the time of enactment. 

Many groups are concerned with the impact the deregulation will have on public health. For example, the American Lung Association and other groups point to increased risk of diseases, more asthma attacks, and more ER visits. The Clean Air Task Force said they will be challenging this action in court on behalf of the American Lung Association, Alliance of Nurses for Healthy Environments, American Public Health Association, and Clean Wisconsin.

Conclusion

Environmental groups and public health groups are preparing challenges to this final rule, calling out concerns for the Trump administration’s environmental actions. The administration has already said it is reconsidering other policies that hinge on the endangerment finding, including regulations on methane, another GHG. The final rule has not yet been published, and members of our Environment, Land, and Natural Resources group will be closely monitoring developments.