During the week of June 15, 2020, the U.S. District Court for the Northern District of California heard from the U.S. Environmental Protection Agency’s (EPA) final three witnesses:  Dr. Joyce Tsuji, Dr. Ellen Chang, and Dr. Tala Henry.  Food & Water Watch, Inc. v. EPA, Case No. 3:17-cv-02162-EMC.  Dr. Tsuji did not dispute that fluoride can be a neurotoxin at “high enough levels.”  Dr. Tsuji contended that the scientific literature remains too limited to establish linkage between fluoride and adverse health outcomes.  Dr. Chang testified on the application of systematic review to chemical usage, a process EPA explored at length with its first witness, Dr. Kris Thayer, as reported in our June 12, 2020, blog item.

Dr. Henry defended the EPA Office of Pollution Prevention and Toxics’ (OPPT) decision to deny plaintiffs’ Section 21 petition.  As Director of EPA's Risk Assessment Division, Dr. Henry expressed the view that “robust science” warranted rejection of the petition.  On June 17, 2020, plaintiffs called back Dr. Kathleen Thiessen as a rebuttal witness, who testified briefly in response to the criticism by EPA’s witnesses of plaintiffs’ methodology in studies mentioned earlier in the trial. After Dr. Thiessen’s testimony, the trial moved to closing arguments.

Plaintiffs’ closing argument asserted that EPA failed to quantify what fluoride levels were dangerous to humans.  District Judge Edward M. Chen interceded to inquire in this regard as tests showing neurotoxicity were well above the level in fluoridation chemicals introduced into water.  Plaintiffs argued the necessity of taking into account inter-species differences from animal testing, as well as human-to-human differences.  Plaintiffs stated that this lack of data seriously hinders determining at what level susceptibility can be found.

EPA responded in its closing that studies relied on by plaintiffs are limited by confounding variables, lack of comparison groups, and double-blind methodologies.  Additionally, EPA noted inconsistencies among the reports plaintiffs cited.  Judge Chen followed up with questions regarding the counter-intuitive findings of effects from fluoride exposure in adult rats but not infants and wanted to confirm if this was a byproduct of the quality of research.  EPA replied that there is insufficient evidence to defend an IQ-urine connection.  Judge Chen also asked if the court could find unreasonable risk from the chemical used by EPA without causation of neurological effects. EPA responded that the only standard provided in the Toxic Substances Control Act (TSCA) regarding unreasonable risk is that which results from an evaluation of that risk, not causation.

After hearing closing arguments, Judge Chen noted that the evidence presented by both parties was not confined to the administrative record and that he allowed both parties to use evidence that was available after plaintiffs filed their petition in 2016 Judge Chen asked plaintiffs and EPA to consider how to reach an agreement, including plaintiffs submitting a new petition or EPA reconsidering its denial of the petition.  Pending Judge Chen's request for additional briefing, there was no ruling on what could potentially be the first half of a bifurcated trial.  A status conference is tentatively scheduled for August 6, 2020, at 10:30 a.m. (PDT).

Co-authored by and Holly M. Williams