Consumer advocacy groups are pressing a federal appeals court to revisit its decision to overturn a landmark ruling that fluoride in U.S. drinking water poses an unreasonable risk to children’s intelligence, arguing the panel relied on flawed procedural reasoning. The petition for rehearing, filed Nov. 12, 2026, by Food & Water Watch, Fluoride Action Network (FAN), and Moms Against Fluoridation, targets the May 21, 2026, ruling by the 9th U.S. Circuit Court of Appeals. That ruling vacated a 2024 decision by U.S. District Judge Edward Chen, which had found current fluoridation levels—0.7 mg/L, endorsed by the Environmental Protection Agency (EPA)—harmful to fetal and child brain development. The rehearing request asks the full court or original three-judge panel to restore Chen’s directive that the EPA initiate rulemaking under the Toxic Substances Control Act (TSCA).
The fight began in 2016 with a citizen petition to the EPA to ban water fluoridation due to neurotoxicity evidence. After the EPA denied the petition, the groups sued the agency under TSCA’s citizen suit provision, a process granting “de novo” judicial review—meaning the court weighs scientific evidence independently w...