Updated:  4/15/26

United States Court of Appeals for the D.C. Circuit
State of Utah, et al. v. United States Environmental Protection Agency
Case No.: 23-1157 (and consolidated cases)

United States Court of Appeals for the D.C. Circuit
National Mining Association, et al. v. United States Environmental Protection Agency
Case No.: 23-1277 (and consolidated cases) 

United States Court of Appeals for the D.C. Circuit
U.S. Steel Corp. v. United States Environmental Protection Agency
Case No.: 24-1172 (and consolidated cases) 

United States Court of Appeals for the D.C. Circuit
Kinder Morgan, Inc., et al v. United States Environmental Protection Agency
Case No.: 25-1054 (and consolidated cases)  

On June 5, 2023, U.S. EPA issued a rule entitled the “Federal ‘Good Neighbor Plan’ for the 2015 Ozone National Ambient Air Quality Standards” (“Good Neighbor Plan”). The Plan requires 23 upwind states to reduce contributions to ground-level ozone (or smog) pollution by setting limits on nitrogen oxides (NOx) pollution emitted from power plants and other industrial facilities in those states. When NOx is emitted into the air, the gas undergoes a chemical reaction whereby a percentage falls from the air, onto land and water as nitrogen, and some combines with other gases to form ground-level ozone. Ground-level ozone pollution seriously harms public health and the environment. 

The Clean Air Act’s “Good Neighbor Provision” requires each state to ensure that its air pollution will not interfere with the National Ambient Air Quality Standards (NAAQS) in downwind or neighboring states. Since NOx pollution travels across state lines, downwind states are burdened by poor air quality caused, in part, by emissions from upwind states, and this interstate pollution interferes with downwind states’ ability to meet the federal ozone standards. 

EPA’s Plan would reduce nitrogen deposition to the Chesapeake Bay watershed and improve air quality and the health of Bay communities, including those most directly impacted by ozone nonattainment and local sources of pollution. For these reasons, CBF joined a coalition of national environmental and public health groups to intervene, in defense of the Plan, in four separate cases filed by states and industry groups in the D.C. Circuit Court of Appeals.   

First, Utah v. EPA in which states and industry groups challenged the Plan itself. Those state and industry petitioners requested a stay of the Plan pending the outcome of the current litigation. CBF and the coalition filed a Motion opposing this request. The Stay request was denied by the D.C. Circuit on October 11, 2023. However, the states and industry groups then filed an Emergency Stay Application with the United States Supreme Court (Ohio, et al v, EPA and consolidated cases). On June 27, 2024, the Court granted the Stay request in a highly unusual decision from its “shadow docket”, before full briefing and consideration on the merits. The Supreme Court’s stay order means the Plan and its benefits are currently blocked pending resolution of the D.C. Circuit litigation. 

See CBF’s press statement on the Supreme Court’s ruling: Supreme Court Blocks Interstate Smog Pollution Rule, Putting Bay Cleanup and Local Communities at Risk  

After the Supreme Court’s decision, the D.C Circuit remanded the administrative record back to EPA to respond to public comments. EPA published a notice in the Federal Register on December 4, 2024 indicating the completion of the remand proceedings. EPA’s response to public comments was then challenged by industry petitioners.  CBF moved to intervene in this case (Kinder Morgan v. EPA) on March 7, 2025.

In separate litigation, states and various industry groups filed petitions for review in the D.C. Circuit challenging EPA’s interim final rule that stayed application of the Good Neighbor Rule in various states pending resolution of separate litigation specific to those states. These suits, filed in October 2023, are consolidated under National Mining Association v. EPA.  In defense of the Good Neighbor Plan, CBF joined environmental and public health partners and intervened in these challenges as the Plan, even when applied to fewer than 23 states, still benefits air quality in downwind states and remains in effect for Maryland, New York, Pennsylvania, Virginia, and various states within the Chesapeake Bay airshed. This third case is currently held in abeyance pending further of the court.

Finally, in the fourth case, industry groups submitted administrative reconsideration petitions to EPA raising various challenges to the Plan. On April 4, 2024, EPA denied these petitions. The industry petitioners challenged these denials in the D.C. Circuit (U.S. Steel Corp. v. EPA and consolidated cases). On July 3, 2024, CBF joined environmental and public health partners in a motion to intervene in the challenge to support the full defense of the Plan and its benefits for air and water quality.

In April 2025, the D.C. Circuit granted EPA’s request to place the cases in abeyance while it reviews the Good Neighbor Plan. On March 23, 2026, CBF joined a coalition of public interest organizations and file comments on EPA’s Proposed Rule to rescind part of the Good Neighbor Plan titled “Proposed Interstate Transport Plan Review of the 2015 Ozone NAAQS Plan.” In the proposed Rule, EPA fails to adequately consider its prior policies, fails to consider health and air-quality impacts, and violates the Clean Air Act. CBF will continue to monitor federal and state activity related to interstate ozone and the Good Neighbor provisions.

CBF is represented in these cases by Director of Litigation Ariel Solaski and counsel from Earthjustice.