The National Toxicology Program

This section is dedicated to the National Toxicology Program’s (NTP) long involvement with the issue of fluoride's toxicity. The NTP is the scientific research arm for U.S. regulatory agencies. It comes under the aegis of the National Institute of Environmental Health Sciences (NIEHS). The NIEHS, in turn, comes under the umbrella of the National Institutes of Health (NIH). -Updated May 2, 2023 (EC).

NTP 2015-2017: Genesis of involvement in fluoride’s neurotoxicity

In 2015, the NTP solicited a request for information in the Federal Register on October 7 on fluoride’s Carcinogenicity, Developmental Neurotoxicity and Endocrine Disruption.  The Fluoride Action Network (FAN) submitted comments (see below) and the NTP made the decision to investigate fluoride’s neurotoxicity.

On December 2, 2015, an Evaluation of Fluoride Exposure and Potential for Developmental Neurobehavioral Effects was presented by Kristina Thayer, PhD, of the Office of Health Assessment and Translation (OHAT), NIEHS, to the NTP’s Board of Scientific Counselors (see below).

December 1-2, 2015. NTP’s minutes of a 2-day meeting with their Board of Scientific Counselors. A lot of the discussion centered on NTP’s Evaluation of Fluoride Exposure and Potential for Developmental Neurobehavoral Effects. The minutes includes questions asked to Kristina Thayer after her presentation (see above) as well as a lively discussion on whether NTP should become involved.

Dr. Howard Pollick, the science advisor to the American Dental Association, attended this meeting. Pollick “noted that the New Zealand study from 2015 indicated that exposure to fluoride had no effect on neurological development or IQ.”
[Note: Pollick was referring to the Broadbent et al., 2015 study. There are several glaring problems with this study, however, including the fact that virtually all of the children in the “non-fluoridated” community used fluoride supplements (a prescription drug designed to deliver the same amount of fluoride a child would get from drinking fluoridated water). FAN discusses these problems here.]

“… Dr. Birnbaum noted that Dr. Bucher and she had both served on the Department of Health and Human Services panel for the revised fluoride exposure safety recommendations. She said nothing is known about differential susceptibility or variability within a population, which was part of the justification for reducing the level recommended for public health protection.”

Dr. Lisa Peterson, Chair of the NTP’s Board of Scientific Counselors, “said the priority for the project ranged from medium to high.”

In July 2016, the NTP released its Systematic Literature Review on the Effects of Fluoride on Learning and Memory in Animal Studies. Research Report 1.

In 2016, the NTP began a “systematic review” of fluoride’s neurotoxicity in humans. This was the first time that any government undertook this task. The draft review took three years and the first draft was released in 2019.

In June 2017 , the NTP’s Office of Health Assessment and Translation released its Protocol for Systematic Review of Effects of Fluoride Exposure on Neurodevelopment.


Submissions to the National Toxicology Program
from Michael Connett and Chris Neurath

In response to NTP’s request for information on fluoride’s carcinogenicity, developmental neurotoxicity and endocrine disruption, the following submissions were submitted from Connett and Neurath on behalf of FAN.


Developmental Neurotoxicity and Endocrine Disruption.

• November 6, 2015. FAN’s submission in response to solicitation for comments in the Oct 7, 2015 Federal Register.

• November 30, 2015. Submission on developmental neurotoxicity and endocrine disruption. Michael Connett.

Comparative sensitivity to fluoride: rodents vs humans

• January 8, 2016. Submission on the sensitivity to fluoride: rodents vs humans. Connett & Neurath.

Fluoride’s Carcinogenicity

•  January 8, 2016. Submission to the National Toxicology Program’s review of fluoride as a carcinogen. Connett & Neurath.

• Appendix 1A. Revisiting the Fluoride-Osteosarcoma connection in the context of Elise Bassin’s findings: Part I. Originally submitted to the NRC on March 2, 2005.

• Appendix 1B. Revisiting the Fluoride-Osteosarcoma connection in the context of Elise Bassin’s findings: Part II. Originally submitted to the NRC on March 2, 2005.

• Appendix 1C. Submission from FAN to the National Research Council Committee: Toxicologic Risk of Fluoride in Drinking Water; BEST-K-02-05-A. Originally submitted to NRC on March 30, 2005.

• Appendix 2. FAN submission to NRC 2006 on cancer [Grandjean 2004]. Originally submitted to NRC on Mary 27, 2004. Submitted to NTP on January 8, 2016.

• Appendix 3. Kenya study abstract [Neurath 2005a]. Correlation between the incidence of dental fluorosis and osteosarcoma in provinces of Kenya.

• Appendix 4. Kenya study of fluoride and osteosarcoma in Kenya [Neurath 2005b]. Introduction and full study.

• Appendix 5. Thiessen submission to California Office of Environmental Health Hazard Assessment, July 2011.

• Appendix 6-A. Review of Kim et al. (2011) & Comparison to Bassin et al. (2006).

• Appendix 7A. Review of Gelberg 1994, 1995 for NTP.

• Appendix 8-A. Review of Blakey/McNally 2014 fluoride-­-­osteosarcoma ecological study Great Britain.

• Appendix 9. Comber 2011 Ireland osteosarcoma­-F study review for NTP cancer review.

• Appendix 10A. Review of Young 2015 F-­osteosarcoma ecological study.

• Appendix 11. Review of Levy 2012 F­-osteosarcoma ecological study USA.