Fluoride in Drinking Water Is Safe. Here’s the Evidence

Municipalities across the U.S. have been safely adding fluoride to their tap water for decades, and reams of data prove the mineral has worked wonders in strengthening enamel and preventing tooth decay. But communities could soon start removing or lowering levels of fluoride in public drinking water as misinformation about its purported harms gains dangerous momentum among media outlets and a growing number of prominent political figures.

This month Robert F. Kennedy, Jr.—President-elect Donald Trump’s current nominee for the next secretary of the U.S. Department of Health and Human Services (HHS)—fueled a fluoride furor on social media when he called the mineral “industrial waste.” Kennedy, a former presidential candidate, inaccurately claimed fluoride exposure could lead to arthritis, bone cancer, thyroid disease, IQ loss and neurodevelopmental conditions. He has said he would advise against adding it to tap water—a practice that currently reaches more than 209 million Americans.

It remains unclear whether the incoming Trump administration could effectively ban water fluoridation: current laws let state and local governments make the decision. But at the federal level, fluoridation opponents could deploy the Safe Drinking Water Act, which regulates water contaminants nationally. They could also take advantage of a recent federal court decision: In September a California district court judge ordered the Environmental Protection Agency to set stricter regulations on tap water fluoride levels, arguing that the HHS’s national concentration recommendations might lower children’s IQ scores. But the judge leaned heavily on a recent controversial scientific report that had been rejected twice in peer review for a lack of rigor.

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“His conclusion was misguided—and an overreach,” says Charlotte W. Lewis, a pediatrician and dental care researcher at the University of Washington School of Medicine. She notes that widely accepted research shows water fluoridation to be an effective disease-prevention measure, especially for people in communities with less access to dental care.

The EPA is currently deciding whether to appeal the district court’s order. But the Trump…