Conspiracy theories sometimes overcome facts in the minds of those who are inclined to believe them. Few public policies have been attacked by conspiracy theorists as persistently as fluoridation. Yet modern science raises legitimate questions about the risks and benefits of fluoridating water.
During the 1950s and into the 1960s, a popular conspiracy theory convinced many believers that fluoridation was a Communist plot. An equally far-fetched theory insisted that fluoride is a mind control chemical that governments rely upon to control their populations.
Fluoridation of public drinking water is intended to prevent tooth decay. While conspiracy theories have no basis in fact, legitimate scientific debates have long addressed the balance between the public health benefits and the risks of fluoridation.
Critics have also complained that fluoridation deprives individuals of freedom to choose whether or not to expose themselves to fluoride. That isn’t quite true, because people are free to forego municipal water and to drink fluoride-free bottled water, albeit at their own expense.
The government often requires people to do things they don’t like (paying taxes, for example) in order to serve the greater good. Debates about the wisdom of public programs that depend on a cost-benefit analysis should be driven by facts. In the case of fluoridation as well as other public health issues, facts are supplied by experts because they have knowledge and experience that the rest of us lack.
Fluoride and IQ
Responding to evidence that fluoridation can have an impact on cognitive development, the Department of Health and Human Services in 2015 recommended that water utilities reduce the amount of fluoride added to tap water from 1.2 parts per million (ppm) to 0.7 ppm. The Centers for Disease Control and Prevention released a statement in 2018 that endorsed fluoridation of community water supplies to reduce the health risks associated with tooth decay.
Dr. Phillipe Grandjean, an Adjunct Professor of Environmental Health at the Harvard T.H. Chan School of Public Health, authored a 2019 review of studies that addressed the relationship between fluoride intake and IQ levels. Dr. Grandjean concluded that “elevated fluoride intake during early development can result in IQ deficits that may be considerable.”
Dr. Granjean concluded that the impact of fluoride on IQ is dose dependent. In other words, greater exposure is likely to have a greater impact on IQ. He also found that “tentative benchmark dose calculations suggest that safe exposures are likely to be below currently accepted or recommended fluoride concentrations in drinking water.”
Everyone agrees that too much fluorine in drinking water would be unsafe. Experts dispute whether the permitted level of fluorine creates an unreasonable risk to the public.
The Environmental Protection Agency (EPA) does not require municipalities to add fluorine to public water supplies, but it does limit the amount that they can add. Since a “safe” amount of exposure is difficult to establish with certainty, opponents of fluoridation argue that it should be not permitted at all.
The Toxic Substances Control Act (TSCA) allows citizens to petition the EPA to address unreasonable risks posed by toxic chemicals. In November 2016, a group of organizations, including the American Academy of Environmental Medicine, the Fluoride Action Network, and Moms Against Fluoridation, petitioned the EPA “to protect the public and susceptible subpopulations from the neurotoxic risks of fluoride by banning the addition of fluoridation chemicals to water.”
The EPA denied the petition on February 17, 2017. It concluded that the studies supplied by the petitioners did not prove that any person had actually suffered neurotoxic harm because of fluoride exposure. The petitioners then sued the EPA for breaching its statutory duty to protect the public from unsafe toxins.
While most administrative decisions are reviewed deferentially by federal courts, the TSCA entitles petitioners to a de novo proceeding and to prove the need for regulation by a preponderance of the evidence. After denying summary judgment motions that had been filed by both parties, the case proceeded to trial.
Petitioners’ Expert Evidence
The petitioners relied on the expert opinions of Howard Hu, Bruce Lanphear, Philippe Grandjean, and Kathleen Thiessen. The EPA and other government agencies have in the past relied on each of those experts for guidance. Their qualifications as experts were not seriously contested.
The petitioners’ experts pointed to evidence that fluoride passes through the placenta into the brain of the fetus. They opined that babies who are bottle fed with fluoridated water are being exposed to fluoride at the most vulnerable point in their lives, while their brains are still developing.
The petitioners’ experts cited animal studies that, according to EPA experts, produced mixed results. The petitioners’ experts also relied on birth cohort studies that found associations between early life exposures to fluoride and a reduction of IQ by about five points.
EPA Expert Evidence
The EPA argued that there is too much uncertainty about safe dosage limits to support an outright ban on fluoridated water. It relied on two toxicologists employed by Exponent, an engineering and scientific consulting firm.
Joyce Tsuji and Ellen Chang testified that the scientific literature does not support a clear connection between fluoridated water at the current maximum dose and adverse health effects. Accordingly, they contended that fluoride at 0.7 ppm is not a neurotoxin.
The EPA contended that the law requires it to balance risks and benefits when it decides whether a risk is unreasonable. There is undeniably a benefit to reducing tooth decay. While that goal can be achieved more efficiently in other ways, fluoridation assures that everyone who drinks from a public water supply receives some protection against tooth decay.
The EPA uses expert staff members to determine whether the benefit of a chemical is outweighed by an unreasonable risk of toxicity. The EPA called its employee, Kris Thayer, as a fact witness to testify about that process. It did not, however, call Dr. Thayer as an expert witness and therefore did not ask her to assess the scientific literature regarding fluoride exposure. The petitioners asked the court to infer that she was not called as an expert because her testimony would have been unfavorable to the EPA.
The petitioners also pointed to the opinion of Joyce Donohue, an EPA staff scientist, who agreed that studies by the National Institute of Health warrant a reassessment of all existing fluoride standards.
Having listened to the expert testimony, the presiding judge pressed the pause button and asked the EPA to reconsider its position. The judge noted that cohort studies are the gold standard of scientific evidence in cases involving toxic chemicals. The cohort studies that the petitioners relied upon had not been published when the petition was filed.
After suggesting that the EPA applied the wrong causation standard, the judge asked whether it would be productive for the petitioners to file an amended petition citing the new studies so that the EPA could make a new determination using the correct standard. He also suggested that the EPA could reconsider its ruling in light of new evidence.
Neither party supported the judge’s solution. The EPA noted that it has no authority to reconsider a petition that it has denied. It also contended that it has no ability to review an amended petition within 90 days as required by the TSCA. The latter argument, amounting to “we don’t have the resources to obey the law,” did not impress the judge.
The petitioners contend that the EPA is entrenched in its position, perhaps for political rather than scientific reasons, and that it is unlikely to budge. The petitioners suggested that giving the EPA a “do-over” would be a waste of time.
The judge postponed proceedings to give the parties an opportunity to negotiate a proposed path forward. If they are unable to come to an agreement by August 6, the judge may decide to make a ruling based on the arguments and expert testimony presented at the trial.