EXCLUSIVE — The Environmental Protection Agency has begun a multiyear study to determine the maximum safe level of fluoride in the nation’s drinking water, advancing a key objective of the “Make America Healthy Again” movement.
Earlier this month, the EPA published a 75-page literature review and study design document outlining its plans to review the effects of fluoride on children’s brain development after a handful of studies showed a correlation between excessive fluoride intake and lowered IQ scores.
Jess Kramer, EPA assistant administrator for the Office of Water, told the Washington Examiner that the initial literature review is a “critical step” in shaping the future of federal drinking water regulations.
“EPA will then dive into what is determined to be the most relevant body of that research to determine what health effects exist, and ultimately to put out a health assessment that will lay out in more detail what the potential health impacts are at certain levels of when you consume certain levels of fluoride drinking water,” he said.
The literature review and study plan are the first steps toward achieving the policy prescriptions set by various members of President Donald Trump’s Cabinet in the MAHA Strategy Report, published in September and spearheaded by Health and Human Services Secretary Robert F. Kennedy Jr.
Fluoride in drinking water, or fluoridation, is a complex policy area with multiple federal, state, and local agencies involved in determining what ultimately comes out of the tap.
State and local jurisdictions are the ultimate decision-makers on whether and to what extent to add fluoride to their water supplies. The EPA, under Administrator Lee Zeldin, determines the maximum contaminant levels for all substances under the Safe Drinking Water Act, setting an upper limit for state and local actors to decide how much to fluoridate.
EPA’s maximum contaminant level informs recommendations from the Centers for Disease Control and Prevention, under Kennedy’s HHS, on what fluoride levels in drinking water are ultimately safest for human health.
Several states, including Utah and Florida, have already taken steps to ban fluoride in their drinking water, and other local jurisdictions across the country have done the same.
Currently, the EPA’s upper limit recommendation, established in 1986, is no more than 4 mg/L, which is higher than in many developed countries.
In 2025, the European Food Safety Committee issued a comprehensive report that found that a 1.5 mg/L was a tolerable maximum fluoride level in drinking water for children older than 8 and adults, including pregnant women. Health Canada reached a similar conclusion in its health hazard report on fluoride last year, also setting an upper limit of 1.5 mg/L.
Kramer said the EPA’s review will occur “over a span of a year to two years” to review the more than 500 pieces of scientific literature and data selected by the Office of Water as relevant for its study.
“It is a lengthy process because of the amount of research and the amount of analysis and the amount of scientific work that has to be done as we go through the process,” he said.
When asked about how the agency is ensuring that the studies selected by the team were not biased against fluoride, Kramer said her agency has created a website listing all of its sources for the public to review.
“We are doing our best to put all of our cards on the table to say we want to get this right. We don’t want bias in our science,” Kramer said.
Philippe Grandjean, head of environmental medical research at the University of Southern Denmark and an adjunct professor at the Harvard School of Public Health, told the Washington Examiner that the EPA’s review is necessary work but must be handled delicately.
“On a societal level, these issues are much more important than white spots on the teeth. However, the research is highly specialized, and interpretation requires substantial experience,” he said.
Grandjean also said that even the best studies can be criticized for failing to account for confounding factors. In this case, that would be other exposures to fluoride, such as pregnant women swallowing toothpaste or drinking certain types of tea.
Scholars from the Harvard School of Dental Medicine published a study in June that found a national ban on fluoride would increase the total number of decayed teeth by 7.5 percentage points and raise dental care costs $9.8 billion over five years.
That’s equivalent to 25 million more decayed teeth and one in three American children experiencing tooth decay.
The American Dental Association has been a staunch opponent to removing fluoride from drinking water, saying children from disadvantaged backgrounds will be most at risk.
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Dr. Richard Rosato, ADA president, said in a statement that the literature review excludes certain studies that show a negative association between fluoridated water and cognitive abilities.
“While this is the preliminary stage assessment, the ADA is hopeful that the EPA will use peer-reviewed,
scientifically tested evidence rather than biased, mischaracterized studies that use flawed datasets and
do not stand up to scientific rigor during the next assessment phase,” he said. “We look forward to continued dialogue with the Trump Administration and Administrator Zeldin on this important public
health issue.”
