Center for American Progress

Ohio v. EPA Threatens the EPA’s Ability To Regulate Air Pollution Nationwide

Ohio v. EPA Threatens the EPA’s Ability To Regulate Air Pollution Nationwide

The case is part of conservative activists’ efforts to stop the Environmental Protection Agency from protecting Americans from major polluters.

The U.S. Supreme Court
The U.S. Supreme Court is seen on March 27, 2020, in Washington. (Getty/Olivier Douliery/AFP)

On February 21, 2024, the Supreme Court will hear oral arguments for an emergency petition to postpone implementing the U.S. Environmental Protection Agency’s (EPA) “good neighbor plan,” which is meant to protect downwind states from high levels of ozone pollution. Unusually, the court is holding oral argument in this matter even though it originates in the notorious emergency docket known as the “shadow docket.” Unlike in the traditional merits docket, cases heard in the shadow docket typically are decided without oral argument on a fast-tracked basis and often are procedural in nature. In Ohio v. EPA, the court has chosen to hear arguments to determine whether the good neighbor plan should be paused while litigation in the lower courts continues. A stay of the plan could allow upwind states to emit approximately 70,000 additional tons of smog-creating nitrous oxide by the peak of the 2026 summertime ozone season, causing up to 1,300 premature deaths and increased hospital visits for thousands of Americans with asthma or other respiratory problems each year. This case serves as another opportunity for this radical, right-wing Supreme Court to rule in favor of powerful industry polluters over the safety and welfare of the American people.

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While the arguments in this case are technically procedural, the court will have to touch on merits to determine whether pausing the plan would cause irreparable harm to Americans’ health and the environment. Further, the merits questions could implicate the recently established and highly problematic major questions doctrine, a legal theory used by the ultra-right-wing justices in West Virginia v. EPA to prevent the EPA from effectively regulating fossil fuel emissions.

The who, what, and why of Ohio v. EPA

The Clean Air Act (CAA) requires upwind states to ensure that their pollution emissions do not interfere with downwind states’ ability to meet federal ozone standards. All states must submit implementation plans to the EPA for approval that include how municipal, local, and state governments will regulate industries to meet the federal regulatory requirements. Should state plans fail to meet these standards, the EPA is required to issue a federal implementation plan instead. In 2023, the EPA disapproved 21 state plans for failing to meet the standards and then issued the good neighbor plan to require that upwind states prohibit or limit the ozone pollutants of certain industries.

Exposure to ozone pollution can lead to major health problems, especially for children and the elderly, including triggering asthma, bronchitis, emphysema, and early death. Since wind carries ozone pollutants across state borders, states must work together to prevent downwind residents from facing dangerous overexposure to these pollutants. In short, because pollution emitted by a power plant in Ohio could affect a child’s asthma in Maryland, this problem is particularly suited to a federal solution.


Ohio v. EPA began when upwind states and regulated industries sued to prevent the EPA’s plan disapprovals as well as the subsequent good neighbor plan from going into effect. Challengers to the plan include the natural gas and oil industries, electrical power companies, a steel producer, and trade associations that represent mining and a variety of other fossil fuel interests. After the U.S. Court of Appeals for the D.C. Circuit denied Ohio, Indiana, West Virginia, and the group of industry litigants’ request to freeze the plan while the litigation is pending, the challengers appealed to the U.S. Supreme Court. They are asking the justices to put the good neighbor plan on hold while litigation continues as to the merits of the plan itself. Adding further complexity to the case, other courts of appeals have paused the EPA’s disapprovals of 12 state plans.

Polluters and their supporters are attacking the EPA from all sides

Right-wing judges are attacking the EPA’s ability to protect Americans from corporate polluters, most recently in Louisiana v. EPA. On January 23, 2024, Judge James D. Cain of the Western District of Louisiana—who, during his confirmation hearing, refused to affirm that Brown v. Board of Education was correctly decided—ruled that the EPA was prohibited from enforcing Section VI of the Civil Rights Act to protect communities from the disparate impacts of pollution.

The case concerns an area of Louisiana dubbed “Cancer Alley,” which is home to predominantly low-income and Black communities as well as more than 200 petrochemical facilities. Due to chemicals that these factories release into the environment, nearly every census tract in Cancer Alley “ranks in the top 5% nationally for cancer risk from toxic air pollution and in the top 10% for respiratory hazards.” After the Louisiana Department of Environmental Quality long refused to protect people living in this area, the EPA stepped in, issuing a letter that laid out evidence that the state has implicitly discriminated on the basis of race when issuing Clean Air Act permits and enforcing air quality standards in Cancer Alley. Thereafter, the EPA opened a civil rights investigation to address the disparate impacts of pollution in these communities; Louisiana’s then-Attorney General and current Gov. Jeff Landry (R) sued to stop the investigation, putting a stop to any meaningful changes to the state’s permitting practices.

At the hearing where Judge Cain entered an injunction to prevent the EPA from enforcing environmental regulations and protecting the health of millions of underserved people, he said, “It’s cheaper to move the people” and wondered aloud why the EPA doesn’t take such action. The lawsuit and ruling have seemingly resulted in chilling the EPA’s enforcement of environmental regulations under Section VI in areas such as Flint, Michigan, and Houston, Texas—leaving the agency with one less tool to protect Americans’ health from polluters.


In hearing the case, the Supreme Court is considering two questions: 1) whether it should stay the good neighbor plan while litigation continues; and 2) whether the emissions regulations the plan imposes are reasonable, regardless of how many states will actually be subject to the plan given lower-court litigation. Solicitor General Elizabeth Prelogar, representing the government, argues in her written brief that staying the program will “significantly harm the public interest,” as it would “delay efforts to control pollution that contributes to unhealthy air in downwind States.” The challengers argue that a stay poses only minimal risk to the public because the good neighbor plan will affect only 11 states—covering less than one-quarter of the emissions the plan was devised to regulate—as the litigation for the other 12 states continues in the appeals courts. The corporate challengers also claim it will cost the natural gas industry alone nearly $1 billion to comply with the EPA’s plan, neglecting that the U.S. oil and gas industry had $332 billion in revenues in 2022.

If the court stays the good neighbor plan, the best-case scenario could be a delay of several years in implementing the plan’s environmental and health protections. At worst, a stay could severely inhibit the EPA from implementing regulations to curb nationwide air pollution and limit health risks. Regardless of how the court rules, challenges to the plan will continue for years to come. The merits of the plan—and the question of whether the EPA can effectively curb downwind pollution—could eventually make it back to the high court. Yet the court’s ruling in West Virginia v. EPA, in which it held that the major questions doctrine prevented the agency from implementing a rule of “economic and political significance” without Congress’ explicit say so, suggests that the outcome of Ohio v. EPA could be similarly perilous.


As noted, challengers to the good neighbor plan include various industry trade groups, companies, and upwind states that will be required to bring their ozone emissions down to the level set by the 2015 National Ambient Air Quality Standards as quickly as possible. Fossil fuel and power sector entities have opposed these limits, mainly on the assertion that they will cost industry too much money, despite the EPA’s inclusion of various flexibilities in the final plan after those concerns were raised during the comment period.

While the state leaders fighting the plan echo the profitability concerns of industry groups, they also appear to be motivated by the same right-wing ideology animating broader legal attacks on Chevron and agencies’ long-standing flexibility to make rules within their domains of authority and expertise. Texas’ interim attorney general, for example, has filed several lawsuits accusing the federal government of overreach, with an email from his office asserting that the EPA’s ability to disapprove state plans “would undercut states’ authority” and “enable the federal government to seize further regulatory power.” Such arguments seem to mirror the ideological underpinnings of The Heritage Foundation’s radical Project 2025 proposals to gut the EPA, including by scrutinizing all good neighbor rules “to ensure that they do not ‘overcontrol’ upwind states” in ways the Supreme Court’s right-wing majority is increasingly disallowing.

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In this way, the fossil fuel sector, industry trade groups, and conservative ideologues have joined forces yet again to dismantle the government’s ability to protect Americans from harmful pollution. And the public health stakes of this particular attack are significant. While longer-term consequences are difficult to quantify and will depend on how deeply the Supreme Court undercuts the EPA’s power to limit smog- and disease-causing emissions, a stay of the good neighbor plan would give an unmistakable green light to its challengers to press their attack.


The EPA has long held the statutory authority to regulate air pollution nationwide. The challenge in Ohio v. EPA asserting that the agency does not have the authority to regulate polluting emissions that cross state lines would be a devastating reversal of the authorities that Congress has explicitly granted it. A ruling that upholds this assertion would further illustrate the manner in which the extreme, right-wing justices on the U.S. Supreme Court continue to rule in the interests of corporations rather than the American people.

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Jeevna Sheth

Senior Policy Analyst

Chris Martinez

Former Associate Director, Domestic Climate

Devon Ombres

Senior Director, Courts and Legal Policy


Courts and Legal Policy

The Courts and Legal Policy team works to advance reforms to make America’s legal system more accessible and just for ordinary people.

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