EPA Revokes Greenhouse Gas Endangerment Finding

Originally published by In the Pipeline

In December 2009, the U.S. Environmental Protection Agency (EPA) issued its well-known “endangerment finding” under the Clean Air Act. That finding concluded that concentrations in the atmosphere of six key well-mixed greenhouse gases (GHG) – carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride – threaten public health and welfare. In the endangerment finding, EPA interpreted the Clean Air Act for the first time to authorize regulation of emissions from new motor vehicles and engines based on global climate change concerns. The finding served as a legal basis for numerous federal rules and emission restrictions that were subsequently promulgated by federal agencies aimed at reducing emissions of methane and other GHGs, extending beyond the automobile industry.    

At the beginning of his second term in office, President Trump issued Executive Order 14154, which ordered the EPA to submit recommendations on the legality and continuing applicability of the endangerment finding. That started a process that led to the action announced on Feb. 12, 2026 by President Trump and EPA Administrator Lee Zeldin: issuance of a final rule rescinding the finding. 

Explaining its decision – which it called “the single largest deregulatory action in U.S. history” – EPA stated that the agency had reevaluated the legal foundation of the endangerment finding and had concluded that the Clean Air Act does not authorize EPA to prescribe motor vehicle emission standards to address global climate change, as the agency had done, and that “a policy decision of this magnitude, which carries sweeping economic and policy consequences, lies solely with Congress” – not an executive agency. While EPA based its recission of the finding on statutory interpretation of the scope of Clean Air Act, it also expressed skepticism regarding the importance of U.S. efforts to reduce GHG emissions, stating that in the years following the finding, many of the scientific predictions and assumptions used to justify GHG emission limits did not materialize. EPA stated: “Using the same types of models utilized by the previous administrations and climate change zealots, EPA now finds that even if the U.S. 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, but regardless, is not within the authority Congress entrusted to EPA.” 

While the immediate focus of EPA’s new action is on the now-repealed motor vehicle emission standards, its potential impact goes much further. That is because the endangerment finding formed the legal basis not just for GHG emission limits from vehicles, but also for GHG rules and emission limits for stationary sources, including sources in the oil and natural gas industry. For example, EPA’s methane regulations and guidelines in Subparts OOOOb and OOOOc flowed from, and were based on, EPA’s conclusion in the endangerment finding that GHG emissions threatened the health and welfare of the public.  While the rescission of the endangerment finding does not automatically eliminate such rules, it does set the stage for potential future efforts to weaken or remove federal GHG rules and emission requirements. Such efforts could come both from litigants using the courts to challenge the validity of current regulations involving GHG emissions, and from federal agencies taking action to modify or revoke those regulations in future rulemakings. 

EPA’s action in rescinding the endangerment finding is controversial and it will be subject to vigorous legal challenges. Numerous states and environmental organizations have already declared that the move was illegal and have stated their intention to challenge it in court. The legal process – which should begin in the U.S. Court of Appeals for the D.C. Circuit and may ultimately include a decision by the U.S. Supreme Court – will probably take many years, and indeed a final determination on the legality of EPA’s action may not be made until the Trump Administration leaves office in January 2029. Congressional action in response to EPA’s decision is also possible.

What is certain is that a major development has occurred in the ongoing debate over climate change and the appropriate scope of federal action to address it. We will keep TPA members informed as to the many developments that are likely to occur in the wake of EPA’s action.