The Supreme Court halted enforcement of the Environmental Protection Agency’s (EPA) “Good Neighbor Plan,” which was implemented to reduce the flow of industrial pollution that is produced in one state from being blown by air currents to other states. 

On June 27, 2024, in the case Ohio v. EPA, the court ruled 5-4 to “enjoin” the EPA from enforcing the Good Neighbor Plan, which required power plants and other polluting industries located in upwind states like Ohio and Indiana to reduce emissions that create ground-level ozone, commonly known as smog that flows to downwind states.

The Good Neighbor Plan sought to reduce ozone-forming emissions of nitrogen oxides (NOX) produced by power plants and industrial facilities in upwind states. That reduction in industrial NOX would result in a reduction of their contributions to smog levels in downwind states, according to the EPA.

To achieve such reductions in emissions, in 2015, EPA revised the ozone “national ambient air quality standards” (NAAQS), and states were required to submit revised “state implementation plans” (SIP) by 2018 that comply with the new, more stringent NAAQS standards.

However, 21 states submitted SIPs in which they proposed to take no action to revise their SIPs because they said existing controls were adequate or that such revisions would not contribute significantly to nonattainment or interfere with the maintenance of existing federal ozone standards in other states.

As a result, EPA took two actions in 2023 to address states’ Good Neighbor obligations under the 2015 NAAQS. The first was, in February 2023 when the EPA disapproved the submissions by the 21 states. The second occurred on March 15, 2023, when the EPA issued a “federal implementation plan” (FIP), which is the Good Neighbor Plan, covering the 21 states that refused to revise their SIPs, as well as two additional states that had not submitted any revisions to their plans. 

The majority opinion—which was delivered by Associate Justice Neil M. Gorsuch—says, “The Clean Air Act (CAA) envisions a collaborative effort between states and the federal government to regulate air quality,” and the EPA “sets standards for common air pollutants.” Under those standards, “states must submit a” SIP that provides “for the ‘implementation, maintenance, and enforcement’ of those standards in their jurisdictions,” opinion was delivered by Associate Justice Neil M. Gorsuch, and it says,  

In addition, “because air currents can carry pollution across state borders, states must also design their plans with neighboring states in mind. Under the CAA’s “‘Good Neighbor Provision,’ state plans must prohibit emissions ‘in amounts which will . . . contribute significantly to nonattainment in, or interfere with maintenance by, any other state’ of the relevant air-quality standard,” the opinion says.

Furthermore, “Only if a SIP fails to satisfy the applicable requirements of the Act (CAA) may EPA issue a” FIP “for the noncompliant state that fails to correct the deficiencies in its SIP,” says the opinion, which adds, “EPA designed its proposed FIP based on which emissions-control measures would maximize cost-effectiveness in improving ozone levels downwind and on the assumption the FIP would apply to all covered states.”

However, the EPA was provided with warnings “that the proposed SIP disapprovals were flawed and that a failure to achieve all the SIP disapprovals as EPA envisioned would mean that EPA would need to reassess the measures necessary to maximize cost-effective ozone-level improvements in light of a different set of states,” but “EPA proceeded to issue its final FIP without addressing this concern.”

Rather, the EPA’s position was its “plan was severable,” and “should any jurisdiction drop out, the plan would continue to apply unchanged to the remaining jurisdictions,” says the opinion. Furthermore, litigation on the SIP disapprovals “vindicated” some of the concerns as the courts stayed 12 of the SIP disapprovals, which meant the EPA could not apply its FIP to those states.

Further still, a number of the remaining states and industry groups challenged the FIP in the D. C. Circuit, arguing that EPA’s decision to apply the FIP after so many other states had dropped out was “arbitrary” or “capricious,” and they asked the court to stay EPA enforcement of the FIP against them while their appeal unfolded. The D. C. Circuit denied relief, and the parties renewed their request in the Supreme Court, the opinion says.

Therefore, “the applications for a stay are granted,” and “enforcement of EPA’s rule against the applicants shall have stayed pending the disposition of the applicant’s petition for review in the D. C. Circuit and (for) any petition for writ of certiorari, timely sought,” says the majority opinion. Chief Justice John Roberts and Associate Justices Clarence Thomas, Samuel Alito, and Brett Kavanaugh are joining Gorsuch.

A dissenting opinion by Associate Justice Amy Coney Barrett says the majority opinion is “based on an underdeveloped theory” that the EPA’s Good Neighbor Plan “is unlikely to succeed on the merits.” Also, the Supreme Court granted “emergency relief in a fact-intensive and highly technical case without fully engaging with both the relevant law and the voluminous record,” says the dissenting opinion.

Furthermore, the majority opinion “suggests that the EPA failed to explain itself sufficiently in response to comments (on the Good Neighbor Plan),” which Barrett says is a “theory (that) must surmount sizable procedural obstacles and contrary record evidence.” In addition, it is the “applicants’ burden” to show that problems with the FIPs, including questions about the FIP’s “dependence on the covered states likely was an ‘important’ problem that EPA ‘entirely failed to consider,’” the dissenting opinion says. “That is on top of their (the applicants’) burden to overcome procedural bar and the lack of ‘significant,’ specific comments raising this issue.” 

Those and other issues support the contention that the applicants “cannot satisfy the stringent conditions for relief in this posture,” says the dissenting opinion. Joining Barrett in the dissent were Associate Justices Ketanji Brown Jackson, Sonia Sotomayor, and Elena Kagan.

Ohio v. EPA was consolidated with three other similar cases, including Kinder Morgan, Inc v. EPA; American Forest & Paper Association v. EPA; and U.S. Steel Corp. v. EPA.

Read the opinions in Ohio v. EPA.