The agency denied the petition filed on November 23, 2016, because of a lack of scientific evidence about the neurotoxic harm from exposure to community water fluoridation, according to a proposed rule published in the Federal Register (February 27).
"After careful consideration, EPA denied [the petition], primarily because EPA concluded that the petition has not set forth a scientifically defensible basis to conclude that any persons have suffered neurotoxic harm as a result of exposure to fluoride in the U.S. through the purposeful addition of fluoridation chemicals to drinking water or otherwise from fluoride exposure in the U.S.," the agency wrote.
The EPA further explained the rationale behind the denial.
"The petition cites several studies as evidence that water fluoridation does not have any demonstrable benefit to the prevention of tooth decay," the agency noted. "However, EPA has found substantial concerns with the designs of each of these studies, including small sample size and uncontrolled confounders, such as recall bias and socioeconomic status."
Prohibiting fluoride addition
Under section 21 of the Toxic Substances Control Act, any person can petition the EPA to amend or repeal one of the agency's rules. Each petition has to follow a certain process in which it sets forth the facts that are claimed to establish the necessity for the action requested, and the agency has 90 days to respond.
As published in the Federal Register, the fluoridation petition urged the agency "to protect the public and susceptible subpopulations from the neurotoxic risks of fluoride by banning the addition of fluoridation chemicals to water." The Fluoride Action Network contended that the "purposeful fluoridation of drinking water presents an unreasonable risk to human health from neurotoxicity."
The Fluoride Action Network petition made the following nine claims, with the EPA's response following each claim.
Overall, the agency stated that the petition did not set forth sufficient facts to justify its primary claims about purported neurotoxic effect from drinking fluoridated water.
- Claim 1: Fluoride poses neurotoxic risks to the U.S. population.
The EPA responded that FAN's petition ignored "a number of basic data quality issues associated with the human studies it relies upon." The agency specifically referred to the human studies cited, which it said were cross-sectional in design and affected by antecedent-consequent bias.
"The antecedent-consequent bias means it cannot be determined whether the exposure came before or after the health effects, since both are evaluated at the same time," the agency wrote.
- Claim 2: Recent epidemiological studies corroborate the findings of neurotoxic risk in Western populations.
The EPA noted that the petition cited two studies from Western populations to attempt to corroborate the assertion that exposure to fluoride in drinking water presents unreasonable risks for neurotoxicity. While the studies made "reasonable use of the population-level data available, causal inference cannot be made from these studies," the agency wrote.
- Claim 3: Studies on both experimental animals and cell cultures are consistent with cited human research linking fluoride exposure with neurotoxic effects in humans.
"Very few studies [that] assessed learning and memory effects at exposure levels near 0.7 parts per million, the recommended level for community water fluoridation in the United States," the EPA responded.
- Claim 4: Susceptible subpopulations are at heightened risk.
The agency stated that no support was available for the petitioner's claims from the data and information provided.
- Claim 5: EPA's 1998 Guidelines for Neurotoxicity Risk Assessment support the need to apply a 10-fold uncertainty factor in deriving an oral reference dose (RfD) or inhalation reference concentration (RfC).
The EPA noted that the petition did not set forth the strengths and limitations of each of the studies in the overall database of available studies nor any criteria or rationale for selecting the eight particular studies from which to derive an RfD or RfC.
"Without setting forth the strengths and limitations associated with each study and the weight of evidence provided by the available database, a necessary step in any assessment, it is not possible to determine whether uncertainty factors are necessary," the agency wrote.
- Claim 6: Fluoridation of drinking water confers little benefit to the public health, relative to the risk.
The EPA responded by stating that it "does not believe that the petition has presented a well-founded basis to doubt the health benefits of fluoridating drinking water."
- Claim 7: There is an unreasonable risk to the U.S. population that lives in areas with community water fluoridation.
The EPA dismissed this claim, stating that FAN and other petitioners have "not set forth a scientifically defensible basis to conclude that any persons have suffered neurotoxic harm as a result of exposure to fluoride in the U.S. through the purposeful addition of fluoridation chemicals to drinking water or otherwise from fluoride exposure in the U.S."
The agency continued, writing that the petitioners have not "set forth a scientifically defensible basis to estimate an aggregate loss of IQ points in the U.S., attributable to this use of fluoridation chemicals."
- Claim 8: Fluoridated drinking water could be "easily and cheaply" eliminated and alternatives products with topical fluoride are widely available, therefore the risks entailed are unreasonable.
The agency noted that the petition cited an already repealed provision of the Toxic Substances Control Act, and this ends-driven reasoning that is "forbidden" by the amended act.
- Claim 9: Fluoridation chemicals are associated with elevated blood lead levels, and laboratory and epidemiological research links artificial fluoridation chemicals with pipe corrosion.
The EPA rejected this statement, stating the petition was not able to present facts that supported the argument.
Michael Connett, an attorney with the Fluoride Action Network and the author of the petition, stated in a release that the agency's decision was unfortunate.
"Unfortunately, the EPA's decision to deny our petition demonstrates that the Agency is not yet prepared to let go of the outdated assumptions it has long held about fluoride," Connett stated.
“It is always heartening when our government comes down on the side of sound science.”
— Gary Roberts, DDS, ADA president
The agency's decision can be challenged in federal court, he noted.
"For too long, EPA has let politics trump science on the fluoride issue," he stated. "We welcome, therefore, having these issues considered by a federal court."
However, the American Fluoridation Society and the ADA welcomed the agency's denial of the petition.
"Once again, fluoridation opponents have been caught misreading or misrepresenting the science. We applaud the EPA's response to this flawed petition," stated Johnny Johnson Jr., DMD, president of the American Fluoridation Society.
Gary Roberts, DDS, president of the ADA, concurred.
"It is always heartening when our government comes down on the side of sound science," Dr. Roberts stated. "Public health policy recommending community water fluoridation results from years of scientifically rigorous analysis of the amount of fluoride people receive from all sources.
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