A Silver Lining: Could the Repeal of the Endangerment Finding Allow for a New Mechanism to Challenge Power Companies Through Public Nuisance Litigation?

by Stella Brocker, Associate Member, University of Cincinnati Law Review Vol. 94

I. Introduction

“Greenhouse gas emissions keep growing. Global temperatures keep rising. And our planet is fast approaching tipping points that will make climate chaos irreversible. We are on a highway to climate hell with our foot on the accelerator.”¹ Climate change is not a new phenomenon. Over the past 800,000 years, the Earth has undergone at least eight documented cycles of ice ages and warmer periods.² However, since the mid-1800s, global temperatures have risen at unprecedented rates, largely due to human activity.³ The effects are evident across multiple environmental indicators, including warming oceans, glacier melting, rising sea levels, and a growing frequency and intensity of extreme weather events.⁴

The largest contributor to global warming is the burning of fossil fuels, such as coal, oil, and gas.⁵ Fossil fuel consumption accounts for approximately 68% of greenhouse gas emissions and nearly 90% of carbon dioxide emissions.⁶ These gases accumulate in the atmosphere and trap heat, leading to warming.⁷ Evidence indicates that current warming rates are about 10 times faster than average post-ice-age warming rates, with present carbon dioxide emission rates being roughly 250 times faster than those observed after the end of the last Ice Age around 11,700 years ago.⁸

In response to these findings, the United States Environmental Protection Agency (EPA) issued the Endangerment and Cause or Contribute Findings for Greenhouse Gases Under Section 202(a) of the Clean Air Act in 2009, commonly referred to as the “endangerment finding.”⁹ The EPA concluded that greenhouse gases pose a public health threat, thereby providing the federal government legal authority to regulate them under the Clean Air Act.¹⁰

However, on February 12, 2026, the EPA overturned the endangerment finding.¹¹ If this action stands, it eliminates the federal government’s legal authority to regulate greenhouse gas emissions under the Clean Air Act.¹² Beyond its regulatory impact, the repeal may have significant implications for climate litigation.¹³ In particular, it could clear the way for federal public nuisance claims against private parties—an action previously blocked by the 2011 United States Supreme Court case American Electric Power Company v. Connecticut.¹⁴ The foundation for this decision rested on the endangerment finding, and its revocation may reestablish federal court jurisdiction over public nuisance claims against private parties, such as power companies.¹⁵

This article explores whether the repeal of the endangerment finding could clear the way for a new wave of public nuisance litigation in federal courts and, if so, what potential implications may follow. Part II provides background on the endangerment finding and the Supreme Court’s reasoning in American Electric Power Company v. Connecticut that previously barred this action. Part III discusses how the repeal of the endangerment finding could unravel this decision and assesses the broader implications for the United States. Finally, Part IV concludes that the repeal of the endangerment finding should now allow private parties to pursue public nuisance claims against power companies in federal court.

II. Background

Since 2009, the endangerment finding has enabled the federal government to regulate greenhouse gas emissions, serving as the foundation for many congressional actions and regulatory efforts.¹⁶ While the government has other tools at its disposal to address climate change, the endangerment finding is a key source of authority for directly tackling global warming.¹⁷ Additionally, the Supreme Court has upheld this finding in multiple landmark cases.¹⁸ Repealing the endangerment finding threatens the very foundation of congressional efforts to address climate change.¹⁹ Without this foundation, the current web of regulations and efforts to tackle this problem may begin to unravel.²⁰ However, the full extent of those consequences and how much of the existing regulatory landscape may unravel alongside it remains to be seen.

A. The Endangerment Finding

Although the endangerment finding was formally issued in 2009, its origins can be traced back to the 2007 Supreme Court decision in Massachusetts v. EPA.²¹ In Massachusetts, a group of plaintiffs, including several states, local governments, and private actors, sued the EPA, arguing that the agency had violated its duty under the Clean Air Act to regulate greenhouse gases.²² The primary question before the Court was whether the EPA has authority to regulate greenhouse gas emissions from motor vehicles.²³ To answer this question, the Court looked to the language of the Clean Air Act, which gives the EPA authority to regulate “air pollutants.”²⁴

The EPA argued that it was not authorized by the Clean Air Act to issue mandatory regulations to address global climate change.²⁵ According to the EPA, the statute was originally designed to regulate local, rather than global, emissions.²⁶ As additional evidence, the EPA pointed out that Congress had considered proposed amendments to the statute in 1990 that would have required the EPA to impose standards for motor vehicle carbon dioxide emissions, which Congress ultimately declined to adopt.²⁷ Because regulating greenhouse gases would have far-reaching economic and political implications, the EPA contended that it lacked the authority to take such action in the absence of express congressional authority.²⁸ Based on this rationale, the EPA argued that greenhouse gases did not fall within the meaning of “air pollutant” under the Clean Air Act.²⁹

The Court rejected this interpretation, finding that the Clean Air Act’s use of “air pollutant” was much broader than the EPA suggested.³⁰ The statute refers to “any air pollutant,” language the Court found to be unambiguous.³¹ The Court further explained that when Congress enacted the Clean Air Act, lawmakers may not yet have understood the direct correlation between greenhouse gases and global warming.³² Given the evolving nature of science, Congress likely intended the statute to retain flexibility so that it could encompass newly identified environmental threats as they became known.³³ Therefore, in using the word “any” to refer to air pollutants, Congress signaled that the statute should apply broadly to pollutants discovered as scientific understanding develops.³⁴

Based on this interpretation, the Court held that greenhouse gases qualify as air pollutants under the Clean Air Act and therefore fall within the EPA’s regulatory authority.³⁵ In accordance with this determination, the Court ordered the EPA to determine whether greenhouse gases pose a threat to public health.³⁶ If such a determination were made, the EPA would be required to regulate them under the statute.³⁷ Following this decision, the EPA issued the 2009 endangerment finding, concluding that six different greenhouse gases threaten public health and welfare.³⁸ This determination gave the EPA statutory authority to regulate these pollutants, which has contributed to a general decline in greenhouse gas emissions over the past ten years.³⁹

B. American Electric Power Co. v. Connecticut

One Supreme Court case that hinged largely on the endangerment finding is American Electric Power Co. v. Connecticut.⁴⁰ In that case, two groups of plaintiffs, including several states and New York City, brought public nuisance claims against four private power companies and the federally owned Tennessee Valley Authority for their carbon dioxide emissions.⁴¹ These lawsuits were filed in 2004, five years before the adoption of the endangerment finding.⁴² The complaints alleged that the defendant power companies were the “five largest emitters of carbon dioxide in the United States” and, as such, contributed to global warming on a large scale, accounting for 10 percent of the country’s human-generated emissions.⁴³ Given their significant contribution to global warming, the plaintiffs asserted that the companies’ emissions created a “substantial and unreasonable interference with public rights” in violation of the federal common law of public nuisance.⁴⁴

Pointing to risks associated with climate change, including risks to public health, land, and infrastructure, the plaintiffs sought injunctive relief requiring defendants to cap their carbon dioxide emissions and gradually decrease them by a specified percentage each year for at least ten years.⁴⁵ The central question before the Court was whether federal courts had the authority to hear such claims.⁴⁶ Ultimately, the Court concluded that it did not, holding that any public nuisance claim regarding greenhouse emissions was displaced by the Clean Air Act, particularly after the EPA issued the endangerment finding.⁴⁷ The Court explained that when Congress enacts legislation addressing a question that was previously governed by federal common law, the judiciary may no longer create its own rules in that area.⁴⁸ To determine whether the statute displaces federal common law, courts ask whether the statute directly addresses the question at issue.⁴⁹

The Court relied on its earlier decision in Massachusetts, which clarified that carbon dioxide emissions qualify as air pollutants under the Clean Air Act, and found that the adoption of the endangerment finding spoke directly to the regulation of the carbon dioxide emissions from the defendant power companies.⁵⁰ Thus, Congress’s statutory actions displaced any authority for the courts to regulate carbon dioxide emissions from fossil fuel-powered plants.⁵¹ The Court further noted that it is likely wise to defer to the EPA’s expertise rather than for judges to decide cases on an individual basis.⁵² Ultimately, the Court held that it may exercise judicial review of the EPA’s actions, but after the official adoption of the endangerment finding, it no longer had authority to designate standards of acceptable levels of carbon dioxide emissions.⁵³

C. The Endangerment Finding is Repealed

After nearly two decades, the Trump administration repealed the endangerment finding on February 12, 2026.⁵⁴ The endangerment finding has been challenged multiple times over the years, mainly as a case of congressional overreach that imposes significant costs on businesses through its restrictions on fossil fuel use.⁵⁵ Despite this, lower courts have repeatedly rejected efforts to overturn the finding.⁵⁶ For example, two groups, the Concerned Household Electricity Consumers Council (CHECC) and the FAIR Energy Foundation, filed multiple challenges to the endangerment finding in 2017 and 2019, but the District Court dismissed their arguments, calling them “inadequate, erroneous, and deficient.”⁵⁷

The EPA has now concluded that the scientific basis underlying the endangerment finding is flawed and therefore must be repealed.⁵⁸ This action does not completely eliminate the EPA’s authority to regulate pollution, as certain pollutants, such as nitrous oxide and ozone, remain subject to regulation under the Clean Air Act.⁵⁹ However, the repeal specifically eliminates the EPA’s legal authority to regulate greenhouse gas emissions from the burning of fossil fuels.⁶⁰ This change significantly hampers the EPA’s ability to address climate change through federal regulation.⁶¹ In response, several environmental groups have already filed challenges to this action.⁶²

III. Discussion

Following the repeal of the endangerment finding, the legal foundation for federal regulation of greenhouse gas emissions has largely been dissolved. As a result, cases like American that relied on that framework will likely no longer hold up.⁶³ This development could open the floodgates to a wave of public nuisance litigation against power companies, a path previously blocked. If such claims are permitted to proceed, individuals and communities harmed by climate change may gain a new avenue to hold major polluters accountable.

A. Implications for American Electric Power Co. v. Connecticut

In American, the Court held that public nuisance litigation was displaced by the Clean Air Act and was no longer in the realm of federal common law.⁶⁴ The repeal of the endangerment finding has eliminated the very authority this case rested upon. The endangerment finding served as the basis for extending the Clean Air Act to include greenhouse gases, thereby granting the EPA authority to regulate those emissions.⁶⁵ Without it, the Clean Air Act does not apply to greenhouse gas emissions. Thus, there is no longer a statutory scheme enacted by Congress that would block public nuisance claims, so they would likely fall back within federal common law or state tort law and could potentially proceed in court.⁶⁶

On February 22, 2026, the Supreme Court granted certiorari in a case originating in Boulder, Colorado, in which the city sued several oil and gas companies, claiming that they knowingly contributed to climate change through their use of fossil fuels.⁶⁷ These complaints were largely based on state tort claims for public and private nuisance.⁶⁸ Colorado’s Supreme Court refused to dismiss the claims, despite the defendant power companies’ arguments that federal law superseded them.⁶⁹

The Court’s decision in this case may signal whether it intends to take an active role in addressing climate-related harms. The plaintiffs will likely argue that American no longer shields power companies from litigation in this arena, which should be a successful argument, based on the Court’s rationale in the case. There, the Court hinged its entire decision on the fact that Congress enacted a statutory scheme to regulate greenhouse gas emissions.⁷⁰ Therefore, in the absence of this statutory scheme, there is no way to justify the claim that Congress intended these claims to be regulated by different agencies. Additionally, without a federal regulatory mechanism addressing greenhouse emissions, injured parties may have no meaningful avenue to seek relief outside of the courts.⁷¹ Given the growing severity of climate-related harms and the widely-documented role of greenhouse gases in driving global warming, the Court should affirm the Colorado Supreme Court’s decision and allow nuisance claims against major emitters to proceed.

B. Broader Implications for the Fight Against Global Warming

The repeal of the endangerment finding leaves far fewer regulatory mechanisms in place to protect against global warming and limit future increases in greenhouse gas emissions. However, if the Supreme Court allows nuisance claims to proceed against private parties, individuals and communities impacted by climate change would gain a new mechanism to seek relief through the courts. In public nuisance actions, plaintiffs typically receive monetary damages as compensation for their injuries.⁷² While this does not undo the harms caused by global warming, it does allow individuals to hold power companies directly accountable in a way that was previously unavailable. Allowing these claims would likely trigger a wave of litigation against large fossil fuel emitters, which could have broad consequences for businesses at large.⁷³ Though not a replacement for comprehensive federal regulations, it could at least require power companies to compensate the communities most severely impacted by climate change.⁷⁴

The EPA has continued to argue that the Clean Air Act preempts state laws regulating greenhouse gases, and therefore, private parties may not sue power companies to hold them accountable.⁷⁵ However, this is an untenable stance. By repealing the endangerment finding, the EPA no longer has authority to regulate greenhouse gases.⁷⁶ Therefore, there is no basis to claim that the Clean Air Act preempts this type of litigation. The EPA is essentially trying to “have its cake and eat it too.”⁷⁷

Ultimately, this determination will be left up to the courts. The only remaining argument supporting the EPA’s position is the claim that there is insufficient evidence to justify regulating greenhouse gases, an argument that has been repeatedly rejected.⁷⁸ Given the growing severity of climate-related harms and the lack of other avenues for relief, the Court should and must conclude that public nuisance litigation may proceed against power companies so that injured parties have a meaningful opportunity to seek relief from those who are largely responsible for the emissions contributing to climate change.

IV. Conclusion

The repeal of the endangerment finding deals a significant blow to efforts to address climate change. In American Electric Power Co. v. Connecticut, the Supreme Court concluded that the Clean Air Act created a statutory framework that granted the EPA authority to regulate greenhouse gas emissions, which are a major contributor to global warming.⁷⁹ Because that authority existed, the Court held that federal public nuisance claims concerning greenhouse gas emissions were displaced and should instead be addressed through the EPA’s regulatory process.⁸⁰

Without this statutory scheme to rely upon, the future of this decision is cast into question. Plaintiffs have already begun bringing lawsuits against power companies, asserting public and private nuisance violations that had previously been blocked.⁸¹ The Supreme Court has already agreed to review a case addressing whether this type of claim can be litigated in federal court.⁸² Given the widespread and well-documented harms caused by climate change, the Court should allow such claims to move forward. Permitting nuisance litigation would provide injured parties with a path to seek relief while also creating a mechanism to hold power companies accountable for their role in producing greenhouse gas emissions that significantly contribute to global warming.

Cover Photo by Ella Ivanescu on Unsplash

Stella Brocker

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