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Lawsuit Forces Early Release of NTP’s Draft Report on Fluoride, and its Potential Association with Neurodevelopment and Cognition
Tuesday, April 4, 2023

A lawsuit by anti-fluoridation activists has forced the early release of a long-awaited government report on fluoride and its possible association with neurodevelopment and cognition while the report is still in draft form and prior to completion of its review by independent scientific experts.

The current draft reports that evidence from scientific studies provides only low confidence of such an association in adults, and just moderate confidence of an association between higher concentrations of fluoride in drinking water – concentrations more than twice those recommended for the US public water supply – and lower IQ in children.  The scientific experts are expected to present the results of their review of the draft report at a public meeting on May 4, 2023. 

The NTP Fluoride Report

The interagency National Toxicology Program (NTP) is supported by three government agencies: the FDA, the CDC, and the National Institute of Environmental Health Sciences (NIEHS) of the NIH. It is administratively headquartered at NIEHS, and its Director (currently Dr Richard Woychik) is also Director of NIEHS.

In 2016, NTP began a systematic review of fluoride’s potential for developmental neurotoxicity in humans. The initial review took three years, and the resulting draft report underwent independent peer review in 2020 and again (after revision) in 2021 by members of the National Academy of Science, Engineering and Medicine (NASEM). After each review, the NASEM committee stated that NTP had not adequately supported its conclusions that fluoride should be classified as a cognitive developmental hazard for humans. As a result, NTP further revised the report, removed the hazard classification of fluoride and split the report into two separate documents: (1) an NTP Monograph on the State of the Science, specifically a qualitative review of published studies on the possible association between fluoride and neurodevelopment and cognition; and (2) a meta-analysis of data from epidemiological studies related to children’s IQ, for submission to a peer-reviewed journal.

In November 2021, NTP submitted the draft Monograph to external peer reviewers, who requested further revisions. Meanwhile, agency experts from CDC, FDA and NIH raised concerns that their earlier comments on the meta-analysis had not been adequately addressed, and that in many instances the NTP authors had disagreed with the comments and criticisms of the agency experts. Further, the agency experts objected to publication (planned for May 2022) until their comments and criticisms, and NTP’s responses, had been considered in a scientifically rigorous manner. Dr. Woychik, therefore, asked NTP’s Board of Scientific Counselors (BSC) to adjudicate the various agency concerns and NTP’s responses.

Since BSC lacked the necessary expertise in-house, it formed an independent working group of scientific experts to handle this task. Once BSC makes its recommendations, it will be up to Dr. Woychik to decide whether to publish the Monograph in its current form or hold it back for additional work, and to submit the meta-analysis manuscript for publication in a scientific journal. He has stated that his decision will be based on scientific criteria and the BSC’s recommendations, and not on any particular regulatory considerations. Since the documents may be highly influential, he indicated that the science must be strong before he can authorize publication.[1]

The Lawsuit[2]

In late 2016, Food & Water Watch (FFW), Fluoride Action Network (FAN), four other organizations, and five individuals submitted a citizen’s petition under the Toxic Substances Control Act (TSCA) to the EPA to ban the fluoridation of drinking water on the basis of fluoride’s possible association with neurotoxicity, especially with respect to cognitive neurodevelopment in the very young. The petition was denied by EPA, but persistence by the petitioners eventually resulted in a trial in the US District Court in San Francisco in June 2020. The trial was halted when the judge asked both sides to work out an agreement.

Plaintiffs then filed a motion to allow them to amend the petition, which EPA denied, but in January 2022 the judge indicated he was not willing to continue the trial until NTP had published the final version of its long-awaited report on fluoride’s possible neurotoxicity. That never happened, and the judge subsequently ruled in favor of plaintiffs’ motion to proceed with the case. Discovery was reopened, allowing for the release of the draft NTP monograph, but since EPA’s objected to the release of any but the final version, the court placed the draft under a protective order, making it available only to the court, the parties and their expert witnesses.

In January 2023, the court “directed the parties to schedule adjudication of EPA’s assertion of privilege over the May 2022 draft of the NTP report and FWW’s entitlement to discovery into critiques of that draft.” Almost immediately, the plaintiffs served NIEHS (not a party to the case) with a subpoena requesting the production of its comments on the draft report, NTP’s responses to those comments, and other documents related to NTP’s decision whether to publish the draft documents. In response to the subpoena, the EPA, NIEHS and plaintiffs agreed to file a Stipulation with Proposed Order to lift the Protective Order, which was granted on February 14, 2023. The stipulation included the following statement:

NIEHS notified Plaintiffs that NTP will be publicly posting to NTP’s website the materials provided to the NTP Board of Scientific Counselors (BSC) working group that is evaluating the comments on the monograph and the related meta-analysis, as well as NTP’s responses thereto. The materials posted will include the May 2022 prepublication monograph and the related meta-analysis, both of which are presently subject to the court’s December 2, 2022 protective order... The posting will also include, without attribution or complete date information, the agency comments sought by the subpoena as well as NTP’s responses thereto.

Thus, on March 15, 2023, NTP posted on its website a full set of the draft documents it had earlier provided to the BSC and BSC’s Working Group, namely:

  • The draft NTP Monograph, including the September 2022 marked-up “working” draft with Reviewers’ Comments and NTP Authors’ Responses (names redacted); the May 2022 “prepublication” draft; and an October 2021 draft.

  • The draft NTP Meta-Analysis Manuscript and Supplemental Materials (July 2022 version), plus Reviewers’ Comments and NTP Authors’ Responses.

  • A September 2020 draft of the combined monograph and meta-analysis, along with NTP’s 2022 responses to NASEM’s 2021 comments on this draft.

Conclusions of Draft NTP Monograph

The September 2022 draft Monograph draws the following conclusions:

  • There is low confidence in the scientific evidence for an association between fluoride exposure and adult cognition.

  • There is moderate confidence in the scientific evidence for an association between higher fluoride exposure (≥1.5 mg/L in drinking water) and lower IQ in children. [That is more than twice the level of 0.7 mg/L recommended by the US Department of Health and Human Services for treating the public water supply. None of the 19 studies relied upon was performed in the US.]

  • There is low confidence in the scientific evidence for an association between fluoride exposure and other cognitive or neurodevelopmental outcomes in children.

The draft Monograph did acknowledge the benefits of fluoride with respect to oral health but noted that they were not the focus of the report.

The BSC Working Group is expected to present the results of its review of the draft Monograph and Meta-Analysis to the BSC at a public meeting on May 4, 2023. The deadline for written public comment submissions and oral comment registration is April 28, 2023.


[1] Food & Water Watch, Inc. et al., v. US Environmental Protection Agency et al. Civil Action No. 3:17-cv-02162-EMC. Second Declaration of Richard P. Woychik. Ph.D., 12-22-2022.

[2] Food & Water Watch, Inc. et al., v. US Environmental Protection Agency et al. Civil Action No. 3:17-cv-02162-EMC, in the US District Court for the Northern District of California, San Francisco Division.

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