As reported in our February 13, 2025, blog item, on January 17, 2025, the Biden U.S. Environmental Protection Agency (EPA) filed a notice of appeal in the U.S. Court of Appeals for the Ninth Circuit of the U.S. District Court for the Northern District of California’s 2024 decision finding that the Plaintiffs established by a preponderance of the evidence that the levels of fluoride typical in drinking water in the United States pose an unreasonable risk of injury to the health of the public. Food & Water Watch v. EPA (No. 25-384). Under the Trump Administration, EPA continued its appeal, presenting legal grounds for reversal rather than asking the appellate court to review the district court’s factual findings on the scientific issues. On May 21, 2026, the U.S. Court of Appeals for the Ninth Circuit filed a memorandum of disposition, vacating the district court’s September 2024 decision and remanding for further consideration.
Background
After EPA denied a 2016 petition filed under Section 21 of the Toxic Substances Control Act (TSCA) requesting that EPA consider whether fluoride in drinking water presents an unreasonable risk of injury to human health, a coalition of non-governmental organizations (NGO) promptly filed suit in the U.S. District Court for the Northern District of California. Food & Water Watch v. EPA (No. 3:17-cv-02162-EMC). After a bench trial in 2020, the district court held the case in abeyance to wait for a final National Toxicology Program (NTP) Monograph that was issued in August 2024. On September 24, 2024, the district court issued its decision, stating that the Plaintiffs established by a preponderance of the evidence that the levels of fluoride typical in drinking water in the United States pose an unreasonable risk of injury to the health of the public. The district court found 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 district court noted that its 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.” The order does not dictate how EPA must respond, but states that “[o]ne thing the EPA cannot do, however, in the face of this Court’s finding, is to ignore that risk.”
EPA’s Arguments on Appeal and the Appellate Court’s Response
EPA claimed that the district court abused its discretion by commandeering the trial and administrative proceedings in violation of the party presentation principle. According to EPA, refusing to rule after the close of evidence at the first trial and determining to accumulate more evidence that the district court, rather than the parties, thought proper, transformed the district court from a neutral arbiter into an advocate. The appellate court agrees, stating that the district 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.” The district court held the case in abeyance, waiting for the NTP Monograph to be published, despite both parties agreeing that it “would be appropriate to decide the merits of the case based only on the first trial record.” Instead, the district court “rejected the parties’ presentation of the case and determined, on its own, that the NTP monograph was relevant and important.”
EPA argued that the district court violated TSCA Section 21 by allowing Plaintiffs to rely on evidence not first presented to EPA in the petition. The appellate court states that, “[b]ecause, against EPA’s initial objection, both parties introduced new evidence to the district court during the first trial that went beyond the evidence presented in the 2016 petition to EPA, we hold that, in these circumstances, the district court did not err in relying on evidence not included in Plaintiffs’ 2016 petition in the first trial.” (Emphasis in the original.) The appellate court declined to address whether TSCA Section 21 allows the introduction of evidence beyond that in the initial petition in different circumstances.
EPA claimed that Plaintiffs’ only relevant standing declarant has water that naturally contains fluoride, and Plaintiffs do not ask that the water utility remove naturally occurring fluoride. Thus, according to EPA, Plaintiffs’ injury is not caused by the addition of fluoride to drinking water, and no available remedy will redress it. The appellate court remanded the issue of standing to the district court for consideration of EPA’s judicial notice request in the first instance. The appellate court states that “[t]he district court as the trier of fact sits in the best position to determine whether to take judicial notice of EPA’s proffered facts and whether these facts affect Plaintiffs’ standing.” Because the appellate court remanded this issue to the district court, it denied EPA’s motion for judicial notice as moot.
Commentary
The appellate court’s decision in this case is a notable milestone in what has been a sprawling administrative and judicial debate on fluoride in drinking water and citizen petitions under TSCA. The petition in question was filed nearly a decade ago — the first such petition submitted to EPA for consideration following the 2016 TSCA amendments. While the statutory provision authorizing citizen petitions (i.e., TSCA Section 21) was not significantly altered in 2016, EPA was tasked with enormous new responsibilities to prioritize, evaluate, and manage risks from existing chemicals with strict statutory deadlines. The 2016 amendments also fundamentally changed TSCA’s “unreasonable risk” standard, replacing the old risk-benefit balancing standard with one that explicitly prohibits EPA from considering costs and other non-risk factors in determining whether or not a risk is “unreasonable.” These changes arguably lowered the bar for citizens to petition successfully EPA to address “unreasonable risk” from existing chemicals.
The statutory structure also creates a procedural oddity: while EPA must undergo a 9- to 12-month process under TSCA Section 6 to prioritize an existing chemical for review and then another 3- to 3.5-year process to evaluate associated risks, private citizens can petition EPA under TSCA Section 21 to skip those steps and proceed directly to the risk management rulemaking. The problem for EPA is that a TSCA risk evaluation forms the primary scientific basis underpinning the development of the risk management rule. Without one, EPA rule writers will not have clear direction on what they are regulating against, and the rulemaking record may be especially vulnerable to legal challenge.
In the case of the fluoride petition, EPA denied the petition on the basis that petitioners had not demonstrated “unreasonable risk.” But the ensuing litigation resulted in a lower court conducting a de novo review of available evidence, concluding that water fluoridation does pose an “unreasonable risk,” and directing EPA to take action. In essence, the court took it upon itself to conduct its own risk evaluation and risk determination, leaving EPA in the difficult position of mitigating a risk that it had neither identified nor defined.
While EPA is no doubt breathing a sigh of relief after the appellate court’s vacatur and remand of this decision, the underlying statutory problem remains. Section 21 petitions have become a source of tension for the TSCA program, short on resources and struggling to keep pace with its core statutory responsibilities. Each petition can represent additional burden for EPA’s existing chemical program. Advocacy groups will likely continue to petition EPA to skip the scientific process and immediately regulate chemicals, and Make America Healthy Again (MAHA) enthusiasts can be expected to be among them. Each successful petition puts more demand on EPA’s limited resources and makes it more challenging for EPA to meet statutory deadlines. Parties may also continue to litigate petition denials and seek an end-run around EPA processes through the federal judiciary. Future reviewing courts may conduct de novo proceedings to determine “unreasonable risk” — a decision that lawmakers explicitly assigned to EPA in TSCA Section 6.
As Congress continues to contemplate legislative amendments to TSCA, Bergeson & Campbell, P.C. would urge consideration of some targeted changes to the citizen petition provisions to better align that authority with the updated processes for prioritizing and evaluating existing chemicals. Minor changes in TSCA Section 21, in particular, specifying that a successful petition would have the substance enter the process at the Prioritization phase rather than risk management, could both increase the stability and predictability of EPA’s workload and avoid the kind of protracted litigation we have seen with fluoride, without undermining the ability of private citizens to elevate their priorities and engage in the TSCA process.
