EPA’s expert witness on risk assessment in the fluoride trial, Dr. Stanley Barone, admitted under oath that for studies finding IQ loss at a certain level of exposure, the standard risk assessment approach that EPA would use is to divide the level of exposure where studies find harm by 10 to reach a level low enough to prevent harm to more sensitive members of a population.

“An uncertainty factor of ten, which is appropriate for all life stages, inclusive of all life stages and vulnerabilities… would be the benchmark MoE.” – Dr. Stanley Barone, EPA Risk Assessment Expert

This is based on the finding that for any toxic substance, a few percent of people will typically be at least 10-times more sensitive than the average person. A dose that is 10-times less than what causes harm in average sensitivity people will cause harm in more sensitive people.

EPA considers this a “protective approach” because under TSCA it must protect all people, not just people of average susceptibility to any particular toxic chemical. When asked by attorney Michael Connett whether he thought EPA should be using a protective approach in its fluoride regulations, Dr. Barone replied:

“A default uncertainty factor for human variability would definitely come into play.” – Dr. Stanley Barone, EPA Risk Assessment Expert

Attorney Michael Connett, who deposed Dr. Stanley Barone twice in 2023, commented on the relevance of Dr. Barone’s admission to water fluoridation:

“Genetics plays a really important role in how people respond to fluoride. Here’s what we don’t know… we don’t know who has that genetic polymorphism that’s going to make them more vulnerable. No one knows. And you know who else doesn’t know… the government. We just know that there is a broad variability in how people respond to fluoride. And given that, we need to have a margin of safety to protect those who are more vulnerable” – Michael Connett

Safe Level Of Fluoride In Water = 0.15ppm

It is generally accepted, even by the dental lobby, that there is evidence of fluoride’s neurotoxic effects at 1.5ppm in water.

If EPA were to enact fluoride regulations consistent with how it regulates other toxic chemicals, according to Dr. Barone, EPA should be using at least a 10x safety factor to account for sensitive subpopulations exposed to fluoride in water.

1.5ppm fluoride in water (observed effect) divided by 10 (MoE, safety factor) = 0.15ppm safe level of fluoride in water.

Explanation of Terms:

• Benchmark MoE = “Margin of Exposure (MoE)”. This term is synonymous with EPA’s regulatory language of “Margin of Safety”, “Uncertainly Factor”, and “Safety Factor”, meaning the number EPA divides by (usually 10) to account for sensitive subpopulations in a chemical’s risk assessment. This provides a margin of safety for all consumers.
• BMCL = A lower confidence limit on the dose of a chemical that produces a biological effect.
• LOAEL = The lowest-observed-adverse-effect level (LOAEL) is a term used by the EPA to describe the lowest dose of a substance that has been reliably observed to cause health effects.  
• NOAEL = No-Observed-Adverse-Effect Level (NOAEL). The highest exposure level at which no biologically significant effects of a chemical have been observed. 

“You Have To Have A Margin Of Safety”

FAN’s own expert witness in the fluoride trial, toxicologist Dr. Kathleen Thiessen, agrees with Dr. Barone.

“If the existing standard had a sufficient margin of safety, that would be below the level recommended for water fluoridation. If the enforceable standard were lowered were it ought to be, somewhere down near zero, then there would be no water fluoridation. You have to have a margin of safety.” – Dr. Kathleen Thiessen, Risk Assessment Expert

Margin of safety is a 500-year-old principle of toxicology that states, “the dose makes the poison,” and we now know that the toxic dose can vary from person to person. Humans have lots of variability. Individuals who are most sensitive to a toxic substance can suffer the same adverse effect as those with average sensitivity, but at a dose that is 10 times lower. In toxicology, a safety margin of 10x is widely recognized as necessary to account for this variation in sensitivity.

Based on the NTP’s systematic review and meta-analysis, which analyzed 74 studies of fluoride and IQ, 22 of which were rated high-quality, fluoridation has a woefully inadequate margin of 2x. And that’s assuming one ignores several high-quality studies finding effects around 0.7 mg/L, the concentration in fluoridated water, which would leave no margin at all.

Federal Judge Agrees: Fluoridation Unsafe For Pregnant Women And Their Offspring

Senior Judge Edward Chen of the U.S. District Court of the Northern District of California also agrees with Dr. Barone and Dr. Thiessen that there is no adequate margin of safety in EPA’s current fluoride regulations.

On page 6 of the historic fluoride lawsuit ruling, Judge Chen wrote:

“The EPA’s default margin of error requires a factor of 10 between the hazard level and exposure level due to variability in human sensitivities…Here, an even greater margin (100x) is owed because the methodology (which yields the 4 mg/L hazard level) uses the lowest observed adverse effect level (“LOAEL”); this methodology adds an additional level of uncertainty (and hence the application of a 100x rather than 10x margin). But even if only the default 10x margin is required, the safe level of fluoride exposure would be 0.4 mg/L (4 mg/L (hazard level) divided by 10). The “optimal” water fluoridation level in the United States of 0.7 mg/L is nearly double that safe level of 0.4 mg/L for pregnant women and their offspring.” – Judge Edward Chen, U.S. District Court of the Northern District of California

The federal court has ordered EPA to initiate a rule making proceeding to come up with a new regulation that will restrict or eliminate the risk posed by fluoridation chemicals to the developing brain, making it clear that EPA cannot “ignore the risk”. EPA has appealed the decision.

Decision makers and legislators can get out in front of delayed EPA rule making by taking steps to end water fluoridation in their communities today. Policymakers and the public should rely on up-to-date science, not outdated endorsements, to ensure public health protection.