A federal appellate court on Thursday vacated a landmark ruling that ordered EPA to address the health risks of fluoride in drinking water, handing the agency a win in a seven-year legal fight with impacts on federal policy and White House politics.
The 9th U.S. Circuit Court of Appeals found a district court judge had “commandeered” the case and abused his discretion by postponing judgment and demanding new evidence and a second bench trial. The unsigned memorandum disposition, issued Thursday, sent the case back to the U.S. District Court for the Northern District of California to rule again — this time based only on the first trial’s record.
Thursday’s ruling follows a contentious 2024 decision by Senior Judge Edward Chen in the district court, where he proffered a lengthy analysis that found fluoride in drinking water at the federally recommended level poses “an unreasonable risk of reduced IQ in children.” That determination triggered a federal rulemaking process under the Toxic Substances Control Act.
It represented an unusual instance where the judicial system disagreed with EPA on the science.
“The district court’s ‘takeover’ of the evidentiary presentation” ultimately constituted “an abuse of discretion,” the judges wrote in Thursday’s appeals court ruling. “Here, the district court effectively provided its own factual presentation,” the memo said.
Judges Sidney Thomas and Ronald Gould, both Clinton appointees, sat on the panel for oral arguments in March along with Brian Morris, chief judge of the U.S. District Court for the District of Montana and an Obama appointee, sitting by designation.
The decision, which does not set precedent, did not address the science behind Chen’s finding. It also declined to address legal questions regarding TSCA citizen petitions.
The case now returns to Chen with a narrower evidentiary record — one that does not include studies that have emerged in the years between the two trials or the final National Toxicology Program monograph, which provided much of the evidence supporting Chen’s decision.
“Based on a threadbare analysis, the Ninth Circuit panel concluded that the district court violated the party presentation principle and ordered the court to travel back in time to August 2020 and render its decision based on the record as it existed at that time,” said Michael Connett, a partner at Siri & Glimstad representing the anti-fluoride plaintiffs.
“EPA did not challenge the factual merits of Judge Chen’s unreasonable risk determination, and, as such, the Ninth Circuit does not either,” Connett continued.
Connett said he “will be reviewing our legal options in the coming days, including the potential of filing a petition for cert to the Supreme Court.”
EPA’s press office said in an email it “is reviewing the Ninth Circuit’s decision.”
The ruling lands as EPA and Health and Human Services Secretary Robert F. Kennedy Jr. are already moving in parallel to reassess fluoride’s safety. EPA Administrator Lee Zeldin last spring launched a review of the science under the Safe Drinking Water Act.
Kennedy has long challenged decades of federal science that fluoride should be added to drinking water systems for their tooth-strengthening properties. Independent researchers say the oral health benefits of fluoride are mainly topical, and there is evidence that points to neurological damages to fetuses and children younger than 6 when ingested, even at recommended levels.
Several communities and at least two states — Utah and Florida — have since voted to end water fluoridation, driven largely by Kennedy and the force of his Make America Healthy Again movement.
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