Federal Court Strikes Down Landmark Fluoride Ruling on Technicality — ‘Not the Science’

A federal appeals court has vacated a landmark decision that found fluoridated drinking water poses an “unreasonable risk” to children’s health under the Toxic Substances Control Act (TSCA).

The decision by the 9th U.S. Circuit Court of Appeals did not challenge the substance of the lower court’s findings — that fluoride is toxic to children and ought to be regulated. Instead, the court based its decision on procedural issues related to the lower court’s handling of the litigation.

The case will now go back to the U.S. District Court for the Northern District of California, where District Judge Edward Chen will be required to exclude all scientific evidence that became available after 2020.

Michael Connett, attorney for the plaintiffs, told The Defender the court “instructed Judge Chen to travel back in time to 2020 and make this ruling based on a stale factual record.”

Connett said the directive to ignore years’ worth of evidence on fluoride’s dangers runs counter to the intent of the TSCA — which is to protect hundreds of millions of Americans from substances that are harmful to human health.

The federal appeals court ruling, handed down late Thursday, stemmed from a lawsuit against the U.S. Environmental Protection Agency (EPA) brought by consumer advocacy groups including Food & Water Watch, the Fluoride Action Network (FAN), and Moms Against Fluoridation.

The groups sued after the EPA refused to consider their 2016 citizens’ petition asking the agency to regulate fluoride.

After two bench trials, Chen ruled that fluoride at the federally recommended concentration of 0.7 milligrams/liter (mg/L) posed an “unreasonable risk” to children’s health and ordered the EPA to regulate it accordingly.

However, the 9th Circuit panel said the lower court violated the “party presentation principle” — a legal doctrine requiring courts to act as neutral arbiters rather than taking control of a case’s factual development.

Connett said the decision was “a very expansive and unprecedented application of the party presentation principle.” He said that to date, “this principle has really only been applied to situations where judges raise new legal issues, not where judges use procedural mechanisms to resolve the issues presented.”

Under the TSCA, if the EPA denies a citizen petition, petitioners have the right to sue the agency. The law is unique because it specifies that the court then evaluates whether the chemical in question presents an unreasonable risk to health or the environment in a “de novo” proceeding, during which it evaluates evidence presented by both sides and gives no deference to the agency.

Rather than ruling after the first trial in 2020, Chen put the trial on hold, pending the release of a multiyear government study into fluoride’s neurotoxic effects, so he could base his decision on all available evidence.

Once that study was released — despite government officials’ attempts to suppress it, which were revealed through Freedom of Information Act requests — the second trial continued and Chen issued his ruling in an 80-page decision detailing the evidence supporting his decision.

The appellate court didn’t comment on plaintiffs’ arguments that TSCA allows this type of judicial procedural discretion, nor did it engage the substance of Chen’s findings.

Instead, in an eight-page decision, the 9th Circuit panel affirmed the EPA’s argument that Chen improperly paused the case for more than a year to await that study, which was not yet available during the first trial. The court concluded that the judge effectively reshaped the evidentiary record, exceeding the proper judicial role.

FAN board member Rick North told The Defender the judgment is a disappointment.

“But this ruling only addresses a legal procedural question — not the science,” he said. “The science remains solid as a rock. As the original court decision asserted, fluoridation ‘poses an unreasonable risk of reduced IQ in children.’ The legal landscape has changed. The risk to pregnant women and their kids hasn’t.”

The judge extended the lawsuit so he could consider the latest, best science, North added. “The court of appeals saw this as judicial overreach. I think most people would see it as due diligence.”

The science that the ruling directs the lower court to ignore includes the National Toxicology Program’s monograph, also published in JAMA Pediatrics, linking fluoridated water and IQ loss in children, and findings from other gold-standard cohort studies.

After the trial concluded, the body of scientific evidence showing fluoride’s adverse impacts on children’s health at current levels in the U.S. has continued to grow.

In May 2024, a study in JAMA Open Network found children born to Los Angeles mothers exposed during pregnancy to fluoridated drinking water were more likely to have neurobehavioral problems.

The ruling is a procedural victory for the EPA. However, since the trial drew national attention to the extensive evidence of fluoride’s neurotoxic effects, communities and states across the country have stopped adding fluoride to their water.

Even the EPA itself — under a different law — has launched a new investigation into the safety of water fluoridation.