On June 27, 2024 the Supreme Court of the United States (“SCOTUS”) granted emergency applications by several states seeking a stay of the Environmental Protection Agency’s (“EPA”) Good Neighbor Plan pending judicial review. The Good Neighbor Plan stems from the EPA’s interpretation of ozone pollution requirements in the Clean Air Act requiring “upwind” states to reduce emissions that affect the air quality in “downwind” states.

Standards issued by the EPA in 2015 required states to submit plans indicating how they would comply with the new standards to reduce emissions affecting air quality in downwind states. Twenty-one states submitted plans that did not contain any changes to reduce downstream emissions, which the EPA rejected. Instead, the EPA proposed its own plan that would cover those states.

In response, the states of Ohio, Virginia, and Indiana challenged the EPA’s plan in the U.S. Court of Appeals for the District of Columbia Circuit, requesting a stay of the plan until the court ruled on the merits. After the DC Circuit refused to grant a stay, the three states requested for SCOTUS to intervene.

SCOTUS granted the challenging states’ request for a stay, holding that allowing the plan to remain in place would infringe on the states’ interests in regulating their own industries and citizens and could prove incredibly costly for the challenger states. The Court also found that the challengers would likely succeed on the merits, finding that the EPA’s plan was flawed because the EPA did not explain why emissions-control measures should still apply even if fewer states remained in the plan, which ultimately occurred.