Fifth Circuit Review of EPA Good Neighbor SIP Disapprovals

This episode discusses judicial opinion from the United States Court of Appeals for the Fifth Circuit addressing legal challenges to the Environmental Protection Agency's (EPA) rejection of state air quality plans for Texas, Louisiana, and Mississippi. The central conflict involves the "Good Neighbor Provision" of the Clean Air Act, which requires states to prevent emissions from significantly impacting the air quality of downwind neighbors. The court ultimately vacated the EPA's disapproval of the Texas and Mississippi plans, remanding them for further consideration after the agency issued a new notice indicating it had relied on updated modeling unavailable to the states during their initial submissions. Conversely, the court upheld the disapproval of Louisiana’s plan because no party sought a rehearing for that specific ruling. Throughout the decision, the court emphasizes the Loper Bright precedent, which mandates that courts exercise independent judgment on statutory meanings rather than simply deferring to agency interpretations. Additionally, the opinion explores the technical disputes over the "one-percent threshold" used to measure significant pollution contributions.