EPA’s Proposal to Rescind the Endangerment Finding

Implications for Federal Permitting, Climate Action Planning, and California Policy

On July 29, 2025, the U.S. Environmental Protection Agency (EPA) proposed a sweeping rule to rescind the 2009 Endangerment Finding—the scientific and legal determination that greenhouse gases (GHGs) pose a threat to public health and welfare. This move, if finalized, would eliminate the legal foundation for federal GHG regulations under the Clean Air Act, including vehicle emissions standards and climate-related environmental reviews.

This proposal marks a pivotal moment in federal climate policy, with far-reaching implications for transportation, infrastructure, permitting, the National Environmental Policy Act (NEPA), state-level climate planning, and even local planning. Clients, especially those navigating NEPA, the California Environmental Quality Act (CEQA), and federal permitting, should prepare for significant regulatory uncertainty.

Legal and Policy Context: Revisiting Massachusetts v. EPA

The 2009 Endangerment Finding was issued in response to the U.S. Supreme Court’s landmark decision in Massachusetts v. EPA (2007), which held that GHGs qualify as “air pollutants” under the Clean Air Act and that EPA must determine whether they endanger public health or welfare. This ruling established the legal foundation for federal GHG regulations, including vehicle emissions standards and climate-related environmental reviews.

EPA’s new proposal challenges this precedent by arguing that Section 202(a) of the Clean Air Act was never intended to regulate global climate pollutants. EPA claims that the original finding was based on flawed science and an overly expansive interpretation of EPA’s statutory authority. This reinterpretation is heavily influenced by two recent legal developments:

Loper Bright Enterprises v. Raimondo (2024)

In this landmark decision, the U.S. Supreme Court overturned the long-standing Chevron deference doctrine, which had allowed courts to defer to federal agencies’ reasonable interpretations of ambiguous statutes. The Court ruled that judges must now exercise independent judgment when interpreting laws, even if the statute is unclear. This shift significantly limits agencies’ ability to justify broad regulatory actions based on their expertise alone.

EPA is using Loper Bright to argue that courts should no longer defer to its previous interpretation that Section 202(a) authorizes regulation of GHGs. Instead, the agency asserts that the Clean Air Act does not clearly empower it to regulate climate pollutants, and that its 2009 finding exceeded the bounds of statutory authority.

The Major Questions Doctrine

EPA also invokes the major questions doctrine, which holds that in cases involving issues of vast economic and political significance, agencies must point to clear congressional authorization for their actions. This doctrine was central to the U.S. Supreme Court’s 2022 decision in West Virginia v. EPA (2021), which struck down the Clean Power Plan for lacking explicit statutory support.

In its current proposal, EPA argues that regulating GHGs under Section 202(a) constitutes a “major question” and that Congress did not clearly authorize such sweeping climate regulation. This legal framing is intended to bolster EPA’s position that the Endangerment Finding should be rescinded because it rests on an impermissibly broad interpretation of the Clean Air Act.

Critics—including legal scholars and environmental groups—argue that this reinterpretation contradicts settled law, misrepresents climate science, and could be deemed arbitrary and capricious under the Administrative Procedure Act.

Impacts on Federal Permitting, NEPA Review, and Climate Policy

Rescinding the Endangerment Finding would likely further undermine the basis for incorporating climate change into NEPA reviews, particularly for transportation and energy projects. The recent U.S. Supreme Court case, Seven County Infrastructure Coalition v. Eagle County (2025), held that agencies are required to analyze only those impacts with a close causal relationship to the proposed action and that the agencies are not responsible for analyzing upstream and downstream impacts separate from the proposed action. This ruling has already diminished the consideration of cumulative climate impacts. (See our blog on the Seven County decision here.) Without a federal determination that GHGs endanger health and welfare, agencies may scale back or eliminate climate-related impact assessments altogether, weakening the analytical rigor of Environmental Impact Statements (EISs) and Environmental Assessments (EAs).

This could also affect Section 7 consultations under the Endangered Species Act, where climate impacts on species and habitats are increasingly considered. Clients involved in federal infrastructure projects should anticipate delays or inconsistencies in how climate impacts are considered across agencies.

Loper Bright and the major questions doctrine signal a more constrained legal environment for federal climate regulation. If finalized, EPA’s proposal could eliminate the legal basis for GHG standards under the Clean Air Act, weaken climate-related NEPA reviews, and disrupt state-level climate planning that relies on federal tailpipe regulations.

Clients should anticipate increased legal uncertainty, especially for projects subject to federal permitting or environmental review. The evolving legal landscape underscores the importance of monitoring regulatory developments, reassessing climate-related assumptions in environmental documents, and preparing for divergent federal and state climate policies.

California-Specific Implications: CEQA, CARB, and Climate Action Planning

For California, the proposal to rescind the Endangerment Finding poses unique challenges:

CEQA Review: Many CEQA analyses rely on federal vehicle GHG standards to model emissions and assess consistency with state climate goals. If federal standards are repealed, CEQA practitioners may need to recalibrate modeling assumptions or rely more heavily on state-level data.

California Air Resources Board (CARB) Clean Air Act Waiver Authority: California’s ability to set stricter vehicle emissions standards under the Clean Air Act depends on EPA granting a waiver. If EPA rescinds the Endangerment Finding, it could argue that GHGs are no longer pollutants subject to waiver authority, jeopardizing CARB’s regulatory autonomy. If this happens, California may argue that if GHG emissions are not regulated under the Clean Air Act, then the state does not need EPA approval for setting its own GHG tailpipe emissions and fuel efficiency standards. Notably, 17 states plus the District of Columbia have adopted California’s stricter vehicle emission standards as allowed under Section 177 of the Clean Air Act.

Local Climate Action Plans: Many local governments in California, and beyond, base their GHG reduction strategies on federal and state tailpipe emissions and fuel efficiency standards. A rollback could complicate compliance pathways and force jurisdictions to revise climate targets or reduction strategies.

Practical Next Steps

Given the potential for litigation and regulatory shifts, we recommend the following actions moving forward:

1. Prepare for Regulatory Divergence: States like California may maintain or strengthen their own GHG regulations. Clients operating across jurisdictions should plan for regulatory fragmentation and dual compliance strategies.
2. Engage in Public Comment: EPA is accepting comments through September 15, 2025. We encourage our colleagues and clients to submit comments that highlight the importance of GHG regulation for project planning, permitting certainty, and climate resilience.
3. Coordinate with State Agencies: Monitor developments with key state agencies to ensure alignment with evolving programs and policies. For California clients, work closely with CARB, the California Department of Transportation (Caltrans), and local air districts to understand how state policies may evolve in response to federal rollbacks. This is especially critical for transportation and infrastructure projects. For clients outside of California, work with your state environmental and transportation departments to keep abreast of evolving state policies and requirements.

Looking Ahead

EPA’s proposal to rescind the Endangerment Finding represents a fundamental shift in federal climate policy. The proposal is expected to face legal challenges, likely reaching the D.C. Circuit of the U.S. Court of Appeals and eventually the U.S. Supreme Court. While the legal outcome remains uncertain, the implications for environmental review, permitting, and climate planning are significant.

ESA’s federal strategy and policy team will continue to monitor developments and provide guidance to clients navigating this evolving landscape—stay tuned for updates by following us on LinkedIn. For questions or support, please contact Brian Schuster, Jeff Caton, or Eric Beightel.