ELR Citation: 56 ELR 20086
No(s). 24-1050 (D.C. Cir. Jun 26, 2026)

The D.C. Circuit denied petitions to review a 2024 EPA rule that revised the NAAQS for fine particulate matter from 12 µg/m³ to 9 µg/m³. Industry groups argued the EPA Administrator lacked statutory authority to reconsider a previous Administrator's 2020 decision to leave the 12 µg/m³ standard in place based upon scientific evidence then available, several states argued EPA's decisionmaking was tainted by environmental justice considerations, and collectively the petitioners claimed the agency action was arbitrary and capricious. EPA moved to vacate the rule on grounds that the Agency exceeded its statutory authority and acted unreasonably by failing to consider costs. The court found the CAA requires the Administrator to "complete a thorough review" of NAAQS every five years, and that the Administrator "may revise them more frequently without completing a thorough review." It thus concluded the Administrator acted within his authority in promulgating the 2024 rule, and "offered reasoned explanations for how he approached and weighed the evidence, and why the scientific evidence supported revision of the NAAQS." It denied both the petitions for review and EPA's motion to vacate.