Fluoride Action Network

Margin of Safety and the Updated NTP Review

Fluoride Action Network | Bulletin | October 2, 2020

By Paul Connett, PhD
Director, Fluoride Action Network

Introduction. When fluoride levels in the public drinking water supply are artificially increased, usually by around 350% using fluoridation chemicals such as fluorosilicic acid, our utility employees and politicians take on the role of a physician or dentist.  Their intent is not to treat the water, but to treat the water consumer as a patient being prescribed a drug for the ostensible purpose of reducing dental decay.

In a clinical setting, practitioners prescribing a drug or treatment to patients work to successfully treat the patient without causing any adverse reactions.  Their goal is to prescribe a dose high enough to be effective, but below what is toxic.  The range between these two doses is referred to as the Margin of Safety (sometimes called Margin of Exposure) of a drug or treatment.

However, unlike a clinical setting, water fluoridation is a treatment administered to an entire community rather than an individual, and there is no control over intake (dose) since people vary greatly in their water consumption and overall exposure to fluoride from all sources.

Everyone is exposed, many for their entire lives, regardless of age, weight, diet, genetics, medical history, total fluoride exposure, or even caries risk.  No consent is given, and by the design of those promoting fluoridation, very few consumers have been informed of potential side effects or risks associated with overexposure.  There is also no follow-up by the “practitioner” in this case or monitoring for adverse-reactions.

This chaotic and unregulated dispensing of fluoride makes the importance of applying a regulatory margin of safety to fluoridation critical in an effort to protect whole populations, including the most vulnerable.  An adequate margin of safety has to take into account the wide range of individual sensitivity expected in a large population and the wide range of doses to which people are exposed.

Hundreds of published peer-reviewed animal and human studies now link fluoride exposure to significant side effects.  According to chapter 20 of “The Case Against Fluoride:

“It is not disputed that, at moderate to high doses, fluoride can cause serious health problems and other adverse effects.  The crucial question is whether there is a sufficient margin of safety between the doses that cause those effects and the doses experienced in fluoridated communities…this margin of safety has to be sufficiently large to protect everyone, including the most vulnerable, not just the average person.  Moreover, it has to be large enough to protect the whole population over a lifetime of exposure.”

Taking just these higher-fluoride-dose studies into account, if the EPA applied the normal toxicological procedures and appropriate margins of safety to fluoridation, the practice would be prohibited.  This is because in toxicology a standard safety factor of 10 is generally used to extrapolate from the result of a small study group (say of 100 -200 individuals) to find a dose which is protective of everyone in a large population (say several million). This is called the “intra species safety factor.” In protecting public health, you have to be conservative. In short, regulators have to assume that there are individuals in the large population who are ten times more sensitive to the toxic chemical in question, than anyone in the small study group.

Fluoride and Neurotoxicity

Turning now to the current situation with fluoride and neurotoxicity, key studies published since 2017, indicate that affects are being observed at the current fluoride exposure levels experienced in fluoridated communities (Bashash 2017, 2018; Green 2019; Riddell 2019; and Till 2020). Adding to the significance here is the fact that nearly all of these studies have been funded by the NIH and as such their methodologies have been extremely rigorous, so there is little wriggle room for doubt on the matter.

This subset of the data (involving exposure to the fetus and the bottle fed infant) is damning as far as the practice of water fluoridation is concerned and that is why we are seeing such desperate efforts by the die-hard fluoridation promoters, who are doing everything to discredit these studies.  These efforts include hounding one of the key authors (Professor Christine Till). But even if we go beyond this subset and examine the totality of all the neurotoxicity studies, there is no salvation for this outdated practice.

The NTP Review

The updated draft of the NTP (National Toxicology Program) systematic review confirms that fluoride is a presumed developmental neurotoxicant. While claiming that the evidence is stronger and more consistent for studies in which subjects were consuming water at or above 1.5 ppm, this conclusion by itself should end fluoridation as a public health policy.  These are the documents released by the NTP:

Clearly, returning to the subject of this bulletin, there is no adequate margin of safety when exposing millions of fetuses, infants and children to concentrations of fluoride in water at 1.5 ppm. This is just a factor of TWO times larger than levels that are typically used in fluoridation programs (0.7ppm) and does not come close to providing the necessary and standard safety factor of TEN.

In conclusion, as confirmed by the National Toxicology Program (the premier toxicological body in the US), the scientific literature is clear and consistent in showing that harm occurs to the developing  brain occurs at or above 1.5 ppm, and thus there is no adequate margin of safety currently between the fluoride levels residents in fluoridated communities are being exposed to and those that are causing harm in NIH-funded studies.

Water fluoridation needs to be discontinued immediately.

For more information, watch this 3-minute video featuring Paul Connett, PhD:


See all FAN bulletins online