ELR Citation: 56 ELR 20029
No(s). 23-60069 (5th Cir. Mar 13, 2026)

The Fifth Circuit, on panel rehearing, vacated EPA's disapproval of Texas' SIP submission to comply with the 2015 revision of ozone NAAQS. Texas petitioned for rehearing, arguing EPA impermissibly relied on data and modeling published after the state filed its SIP that was markedly different from the guidance given to states before submission. The court previously upheld the disapproval because both EPA's and Texas' modeling showed emissions that the Agency concluded triggered good neighbor obligations and EPA's reference to its own data when discussing the data in the SIP did not undermine the conclusion that the Agency independently assessed and rejected the SIP on its merits. On rehearing, the court found that a subsequent notice of proposed rulemaking stated that the Agency did utilize data published after submission to disapprove the SIP. Finding that it could no longer conclude with confidence that EPA's disapproval was based on its technical review of the data and reasoning Texas offered, and that the Agency had not settled on how it would evaluate SIPs submitted in response to the revised ozone NAAQS, the court vacated the disapproval and remanded to EPA.