Connecticut Gov. Ned Lamont this week signed legislation requiring the state to keep fluoride at existing levels. But Florida and Utah have banned adding fluoride to drinking water, and other states may follow, as the decades-old practice of adding it to public drinking is facing renewed attacks, including from the federal government.

Arkansas state Sen. Bryan King, a cattle and poultry farmer in Fayetteville, told CBS News he has “concerns” about adding fluoride to water. 

Since 2011, when the state mandated most public drinking water to include fluoride, King has thrown his anti-fluoride voice behind a handful of bills seeking to repeal that mandate.

Fluoride is a natural mineral. It strengthens teeth and fights dental decay. It’s been added to the U.S.’s public drinking supply since the 1940s. 

The U.S. Centers for Disease Control and Prevention rated fluoride as one of the top ten public health achievements of the 20th century.

And according to the American Dental Association, “70 years of research, thousands of studies and the experience of more than 210 million Americans tell us that water fluoridation is effective in preventing cavities and is safe for children and adults.”

“If that’s the case, they need to individually go out to each water district and sell it to the people there, and let them make their own water decisions,” King said.

At least 19 states have considered legislation to remove, ban or make fluoride optional in public drinking water this year. One of fluoride’s most prominent critics is Health and Human Services Secretary Robert F. Kennedy Jr.

In the latest skirmish over science, fluoride opponents argue that at high levels, it can lead to kidney and liver damage and lower IQs in children.

The National Institutes of Health’s toxicology program in 2024 determined “with moderate confidence” that there is a link between high levels of fluoride exposure and lower IQs in children. That conclusion was based on studies involving fluoride levels of about twice the recommended limit for drinking water.

The American Academy of Pediatrics has questioned the validity of the NIH’s report, noting it had “important limitations,” including the high fluoride levels, and that other reviews have come to different conclusions about fluoride’s risks and benefits.

The EPA in 2011 lowered the recommended limit for fluoride in water to cut down on fluorosis — when spots appear on kids’ teeth — and in the wake of a 2006 report from the National Academy of Sciences that found a lifetime of overconsumption of fluoride can lead to weakened, brittle bones and teeth.

At Arkansas’ Fort Smith water system, Lance McAvoy, who oversees the system, told CBS News it’s monitored 24/7.

“We actually take samples every 15 minutes to verify the online equipment,” McAvoy said, adding there had never been an instance of significantly higher fluoride levels to date.

Dentists such as Kenton Ross, who also serves as president of Arkansas’ dental association, say the science supporting fluoride is indisputable.

“You’re gonna see a 25% reduction in tooth decay,” Ross said of adding fluoride to drinking water. “We have over 75 years of research over community fluoridation.”

For dentists, losing fluoride could mean losing the battle against tooth decay.

“It’s gonna affect the children the worst because if they don’t get it, we can’t put it in later in life,” Ross said.

Alexander Tin and

Sara Moniuszko

contributed to this report.