Medical experts warn the move could have consequences for oral health, especially among children.
Utah has become the first U.S. state to outlaw the addition of fluoride to public drinking water.
The law, which was signed by Gov. Spencer Cox on March 27 and will go into effect on May 7, comes amid renewed scrutiny of fluoride, a mineral that has been widely added to U.S. drinking water since 1945 to prevent cavities. Although controversy over the safety of water fluoridation first arose in the 1940s, concerns have intensified in recent years, driven in part by new research on fluoridation and by growing resistance to public health interventions since the pandemic.
In November, Robert F. Kennedy Jr., now the federal health secretary, said that the Trump administration would “advise all U.S. water systems to remove fluoride from public water” because of potential health risks. Anti-fluoridation bills have also been introduced in North Dakota, Tennessee and Montana.
Much of the concern centers on the possible cognitive effects in children. In one recent review of studies, researchers concluded that high levels of prenatal or childhood fluoride exposure were linked with lower I.Q. s in childhood. But the fluoride levels associated with cognitive problems were more than twice as high as the levels people are generally exposed to through community water fluoridation, said Dr. Scott Tomar, a public health dentist and oral epidemiologist at the University of Illinois Chicago.
Some Americans are exposed to high levels of fluoride in their water through natural contamination from rocks and soil, he said, but not from manual fluoridation. The risks of manual fluoridation “have been dramatically overstated,” Dr. Tomar said.
Gov. Cox has not publicly alluded to health concerns relating to fluoridation, and the bill does not mention any either. He instead has previously said that the oral health benefits of water fluoridation have been insubstantial in Utah, where about 44 percent of residents who were provided with public drinking water consumed fluoridated water in 2022.
Nearly half of the state has been drinking fluoridated water, while the other half has not. Between those two groups, Gov. Cox said, “you think you would see drastically different outcomes. We haven’t.”