ELR Citation: 56 ELR 20070
No(s). 25-384 (9th Cir. May 21, 2026)

In an unpublished opinion, the Ninth Circuit vacated a district court finding that adding fluoride to drinking water at a concentration of 0.7 milligrams per liter (mg/L) presented an unreasonable risk to human health. Opponents of fluoridation had petitioned EPA in 2016 to issue a rule banning addition of fluoride to drinking water pursuant to §21 of TSCA. EPA denied the petition and the opponents sued under §21's judicial review provision. The district court, in the second of two bench trials, held that addition of fluoride to drinking water at 0.7mg/L presented an unreasonable risk to human health, and ordered EPA to manage associated risks in accordance with TSCA. EPA appealed, arguing the district court erred by taking over the suit and holding a second bench trial in violation of the party presentation principle, reviewing an evidentiary record that differed from the one presented to the Agency in the 2016 petition, and by ruling that the opponents had standing. The appellate court agreed that the district court violated the party presentation principle in its handling of the suit after the close of the first trial, but did not err in relying on evidence not included in the 2016 petition in the first trial. It vacated the decision and remanded the issue of standing.