Blog | What’s New in EPA’s Final Rule Rescinding the Endangerment Finding

On February 12, 2026, the U.S. Environmental Protection Agency (EPA) announced a Final Rule rescinding its 2009 Endangerment Finding for greenhouse gases (GHGs). In September, the Georgetown Climate Center summarized EPA’s proposal to rescind the landmark rule.^{See footnote 1}  For the past 16 years, the Endangerment Finding has served as the basis for EPA’s regulation of GHG emissions from vehicles under the Clean Air Act (CAA). EPA’s Final Rule marks a significant reversal and it is already being challenged in court.

Like the Proposed Rule, EPA’s Final Rule re-interprets the CAA to restrict EPA’s authority to address global climate change. Unlike the Proposed Rule, EPA’s final rescission no longer relies on a July 29 report prepared for the U.S. Department of Energy by a working group of five scientists skeptical of the prevailing scientific consensus about the impacts of climate change—the Final Rule drops this alternative basis for rescinding the Endangerment Finding. 

EPA argued in the Proposed Rule that, despite eliminating its ability to regulate climate-warming emissions from vehicles under the CAA, the CAA still preempts: (1) state regulations of emissions from vehicles and (2) the filing of federal common law claims against sources of greenhouse gas emissions. Notably for states, the Final Rule makes a third argument that state common law claims against sources of greenhouse gas emissions are also preempted. This post highlights key elements of EPA’s Final Rule and explains EPA’s additional preemption argument.

EPA Rescinds the 2009 Endangerment Finding but Drops Dispute of Climate Science

The 2009 Endangerment Finding has served as the legal prerequisite for EPA’s regulations of GHG emissions from motor vehicles under the CAA. In that finding, EPA concluded that six greenhouse gases endanger public health and welfare by contributing to climate change. EPA’s Proposed Rule included three bases for rescinding the Endangerment Finding and/or existing federal GHG emissions regulations for vehicles. Only two remain in the Final Rule.

Significantly, EPA dropped its argument that climate change is not actually harmful to public health and welfare. In the Proposed Rule, EPA argued that—even if its statutory arguments fail and the CAA gives EPA authority to address climate change—the 2009 Endangerment Finding’s scientific analysis was unreasonable and recent developments cast doubt on its conclusions about the harms of climate change. 

In making this argument, EPA relied on a report produced for the Department of Energy by a working group composed of prominent climate skeptics. Commenters such as the National Academy of Sciences robustly disputed that argument and provided scientific evidence in support of climate change and its harms. A federal district court in Massachusetts also determined that the Administration’s formation of the climate working group violated certain procedural and fairness requirements of the Federal Advisory Committee Act. Although EPA notes that it “continues to harbor concerns regarding many of the scientific inputs and analyses underlying the Endangerment Finding,” it ultimately left that argument out of the Final Rule. 

In the Final Rule, EPA’s primary approach for rescinding the Endangerment Finding is largely unchanged from the proposal: EPA argues that it lacks statutory authority to regulate emissions contributing to climate change. EPA’s statutory argument has three main parts, and the agency argues that each is independently sufficient to repeal the Endangerment Finding. 

• First, EPA argues that the best reading of the text of CAA section 202(a) does not empower EPA to set standards for vehicle emissions to address global climate change. As in the proposal, EPA argues that “air pollution,” as that term is used in the CAA, extends only to pollution with local or regional effects, and does not extend to a global phenomenon like climate change. EPA also asserts (as it did in the proposal) that the statutory terms “cause” or “contribute,” as they are used in the CAA, require an endangerment finding to be both pollutant- and source-specific before serving as a basis for regulation, and that the connection between GHG emissions from new motor vehicles in the US and the dangers of climate change is too attenuated or de minimis to support such a finding. 

• Second, EPA asserts that, even if the text of the CAA plausibly allows EPA to regulate GHG emissions from vehicles, the major questions doctrine—as explained in recent cases like West Virginia v. EPA—prohibits EPA from reading the CAA that way. In other words, EPA says it lacks clear congressional authorization to regulate vehicle emissions to address climate change. 

• Third, EPA also argues that its attempt to address climate change through regulation of GHG emissions from US vehicles has been “futile, which further supports the conclusion that CAA section 202(a)(1) was not designed with such a problem in mind.” EPA’s “futility” argument also shows up in the Final Rule’s fallback approach for repealing the vehicle standards, which—like an option described in the Proposed Rule—would repeal all GHG emissions standards for new vehicles and engines independent of rescinding the Endangerment Finding. EPA argues it would be “unreasonable to maintain the GHG emissions program” because “the costs or regulation are certain and immense but the health and welfare value of regulation are uncertain and de minimis.”

Any of EPA’s three statutory arguments would, if upheld, limit future administrations from using CAA authority as a tool to regulate greenhouse gas emissions from vehicles to address climate change. EPA asserts that its statutory arguments are consistent with the Supreme Court’s decision in Massachusetts v. EPA, but it is hard to imagine how the Final Rule could be upheld without overruling some or all of that key precedent. In Massachusetts, the Supreme Court held that the CAA is “unambiguous” in authorizing “EPA to regulate greenhouse gas emissions from new motor vehicles in the event that it forms a ‘judgment’ that such emissions contribute to climate change.” The Court also explained that EPA could only refuse to regulate GHG emissions from vehicles if the agency determined that GHGs “do not contribute to climate change or if” the agency provided “some reasonable explanation as to why it cannot or will not exercise its discretion to determine whether they do;” it could not decline to take action because of other “policy judgments.” Finally, the Court explained that an early major questions doctrine case, FDA v. Brown & Williamson Tobacco Corp., was inapplicable because “there is nothing counterintuitive to the notion that EPA can curtail the emission of substances that are putting the global climate out of kilter.”

EPA’s Final Rule Adds a Third Preemption Argument

In the Proposed Rule, at the same time EPA re-interpreted the CAA to limit federal authority, EPA made two preemption arguments relevant to states seeking to reduce GHG emissions through their own programs. The Final Rule adds one new preemption argument concerning state common law claims against sources of GHG emissions.

In the Proposed Rule, EPA first asserted that state emission standards for new vehicles would remain preempted by CAA section 209(a) because new vehicles “would remain subject to Title II of the CAA” even if no federal GHG standards were in place. Second, EPA asserted that its proposal would not disturb the Supreme Court’s conclusion in American Electric Power Company (AEP) v. Connecticut that “the Clean Air Act and the EPA actions it authorizes displace any federal common-law right to seek abatement of carbon-dioxide emissions from fossil-fuel fired powerplants.” 

In the Final Rule, EPA adds a new preemption argument: in addition to displacing federal common-law claims to abate GHG emissions, the CAA “continues to preempt state common-law claims and statutes that seek to regulate out-of-state emissions, independently of CAA section 209(a)’s express preemption provision for mobile-source emissions.” 

Although EPA argues that the CAA “continues” to preempt these types of claims, whether that is actually the case is unsettled. In AEP v. Connecticut, the Supreme Court left open the question of whether the CAA displaces state common-law claims in the same way it displaces federal common-law claims. In AEP’s wake, lower courts have reached different conclusions. Notably, the U.S. Department of Justice (DOJ) filed cases in April against Michigan and Hawai’i, attempting to prevent both states from filing these sorts of state common-law claims against fossil fuel companies and arguing, among other things, that the CAA preempted them from doing so. DOJ also filed an unsolicited amicus brief with the Supreme Court, asking it to overturn a Colorado Supreme Court decision allowing the City of Boulder to bring state common-law claims against Suncor and other fossil fuel companies because of their contributions to climate change. The Supreme Court granted cert in that case on February 23, 2026, and will likely hear arguments during its next October Term.

EPA’s preemption arguments in the Proposed and Final Rules are notable because they show the agency’s interpretation of the law in light of its significant rollback of the Endangerment Finding. However, EPA’s arguments in the Final Rule are not binding interpretations of the statute and whether those arguments—or the Endangerment Finding rollback as a whole—will prevail remains to be seen.

On February 18, 2026, 17 environmental and public health organizations filed a petition for review in the U.S. Court of Appeals for the District of Columbia challenging the legality of EPA’s Final Rule rescinding the Endangerment Finding. Georgetown Climate Center will watch this appeal—and any potential Supreme Court case following it—closely.

Amanda Lineberry is a Senior Associate with the Georgetown Climate Center.