Food & Water Watch v. EPA: the fluoride ruling under TSCA, the Ninth Circuit's vacatur, and what EPA is doing instead

What it says#

The case began with a petition. On November 23, 2016 the Fluoride Action Network, Food & Water Watch and four other groups asked EPA, under section 21 of the Toxic Substances Control Act, to issue a rule prohibiting fluoridation chemicals as drinking water additives; EPA denied it on February 17, 2017, and the groups sued on April 18, 2017. TSCA, as amended in 2016, lets a court decide such a petition "de novo, i.e., without deference to the EPA's decision," as Judge Edward M. Chen's findings put it, and if the court finds an unreasonable risk "it then orders the EPA to engage in rulemaking regarding the chemical."

After a seven-day bench trial in June 2020 the court did not rule; it held the case in abeyance, and in the order doing so said it had "serious questions" about standing. It lifted the abeyance in October 2022, allowed a second round of discovery so that the National Toxicology Program's monograph could come in, and held a second bench trial beginning January 31, 2024. The findings of fact and conclusions of law, Docket 445, came on September 24, 2024, in 80 pages. The holding: "the Court finds that fluoridation of water at 0.7 milligrams per liter ('mg/L'), the level presently considered 'optimal' in the United States, poses an unreasonable risk of reduced IQ in children." The next sentences are the ones a patient rarely hears: "It should be noted that this finding does not conclude with certainty that fluoridated water is injurious to public health; rather, as required by the Amended TSCA, the Court finds there is an unreasonable risk of such injury, a risk sufficient to require the EPA to engage with a regulatory response. This order does not dictate precisely what that response must be." The court added that EPA's options "can range from requiring a mere warning label to banning the chemical," and that "one thing the EPA cannot do, however, in the face of this Court's finding, is to ignore that risk." The conclusions of law ordered "the Administrator to initiate rulemaking pursuant to Subsection 6(a) of TSCA." Judgment was entered November 20, 2024.

The evidence the court leaned on was the NTP monograph and the studies behind it: the findings note that "a large majority of the 72 epidemiological studies assessed by the NTP Monograph observed this relationship including all but one of the 19 high-quality studies," and the court used a lowest-observed-adverse-effect level of 4 mg/L in water as its point of departure, finding the margin to 0.7 mg/L insufficient once maternal urinary fluoride and susceptible populations were considered. On January 5, 2026 the court awarded the plaintiffs $5,263,705 in fees and $496,745 in costs, "payable subject to the pending appeal."

EPA filed its notice of appeal on January 17, 2025; the Ninth Circuit docketed it as No. 25-384. The panel heard argument on March 3, 2026 and on May 21, 2026 issued an unpublished memorandum: "we vacate the district court's decision and remand." The ground was procedural. The court "abused its discretion when it refused to rule on the first trial record, despite the parties' assertions that it should, and when it held the case in abeyance to wait for the completion of an additional study to which the parties had already stipulated not to present at trial." Holding the case "in abeyance for a year and a half and declining to rule on the first trial record as requested by both parties went 'well beyond the pale.'" The remand instruction is specific: "rule based solely on the first trial record," and decide EPA's standing objection "in the first instance." The panel did not reach whether 0.7 mg/L is an unreasonable risk, and it "decline[d] to address whether Section 21 of TSCA would allow the introduction of evidence beyond that contained in the initial petition under different circumstances."

Who it applies to#

Directly, EPA and the plaintiffs. The order ran against the agency, and nothing in it regulated a water system, a state or a dental office. Its reach into practice is through patients: the September 2024 ruling is the decision cited whenever someone says a federal court found fluoridation unsafe, and it was cited in state fluoridation debates through 2025. The ADA filed an amicus brief supporting EPA's appeal on July 25, 2025, and on May 22, 2026 said it "applauds" the Ninth Circuit's decision, with its president adding that "the lower court ruling relied in part on materials that were never presented to the EPA, making the decision to require additional review of fluoride standards unjustified."

The regulatory numbers a patient may have heard are unchanged by the case. EPA's fluoride page says the enforceable maximum under the Safe Drinking Water Act "at 4.0 milligrams per liter" was "set in 1986 and most recently reviewed in 2024," and that "the decision on whether or not to add fluoride to drinking water is made on a state or local basis; EPA does not make recommendations on adding fluoride to drinking water."

What changed#

Two things, on separate tracks. In the courts, the 2024 finding is vacated. As of September 13, 2026 the district court docket shows the Ninth Circuit's memorandum filed May 21, 2026; an order of June 3, 2026 directing EPA to respond to the plaintiffs' motion to clarify the scope of the remand on standing; an order of August 10, 2026 granting the plaintiffs 90 days from that date to file a petition for panel rehearing or rehearing en banc; and, in the separate appeal of the fee award, No. 26-1365, an August 24, 2026 order closing that docket administratively until November 24, 2026, stating that "no mandate will issue in connection with this order." No mandate had issued in No. 25-384 either, and the district court had not ruled on the first trial record. Whether the plaintiffs will seek rehearing, and what Judge Chen will find on the 2020 record, could not be determined at the check date.

At EPA, the agency chose a different statute. On April 7, 2025 Administrator Lee Zeldin announced "the agency's decision to expeditiously review new scientific information on potential health risks of fluoride in drinking water," describing it as work "that will inform agency decisions on the standard for fluoride under the Safe Drinking Water Act" and quoting Zeldin: "Without prejudging any outcomes." On January 22, 2026 EPA released its Fluoride Preliminary Assessment Plan and Literature Survey for comment, noticed in the Federal Register on January 28, 2026 with comments due February 27; the notice says the plan "is not a toxicity assessment; it does not contain conclusions regarding harmful human health effects of fluoride." The same day's press release explained that "after reviewing the agency's statutes, including the Toxic Substances Control Act (TSCA) and the Safe Drinking Water Act (SDWA), the agency determined that moving forward with a review under SDWA, led by the Office of Water, was an appropriate pathway." On August 3, 2026 EPA released the Protocol for Developing the Fluoride Human Health Toxicity Assessment, which will "consider neurodevelopmental effects in children (e.g., negative effects on brain function, including lower IQ)" and dental fluorosis, with a draft assessment to follow for peer review and comment. None of EPA's fluoride pages read for this entry describes a TSCA section 6 rulemaking.

Where the source is#

The district court's findings are free on govinfo in the United States Courts collection, document 15 of the case package, and on CourtListener's RECAP archive as Docket 445; the abeyance order, the order lifting the stay, the pretrial order and the January 2026 fee order are in the same govinfo package. The Ninth Circuit memorandum is on the court's public datastore, and the June 3, August 10 and August 24, 2026 appellate orders were read from the RECAP copies filed on the district docket. EPA's April 2025, January 2026 and August 2026 releases and its Fluoride in Drinking Water page are on epa.gov, which served them to a browser-identified client; the January 28, 2026 Federal Register notice is on govinfo. The ADA press release is on ada.org. The NTP monograph itself has its own entry in this directory.