Hillsboro voters will advise city whether to add fluoride to water supply

Hillsboro voters this fall will advise the city whether to add fluoride to the public water supply, weighing in on a mineral that’s widely used to strengthen tooth enamel but that opponents say can hurt children’s neurological development.

Hillsboro pediatrician Beth Mossman spearheaded the effort to have city residents vote on the addition of fluoride. In June, the City Council approved placing non-binding advisory Measure 34-338 on the November ballot to ask for the community’s opinion on fluoridation.

The measure has brought the fight over fluoride’s health impacts to the forefront. Arguments largely mirror those that erupted in Portland 11 years ago when a similar, highly controversial proposal appeared on the ballot. Voters ultimately rejected it 61% to 39%.

Fluoride is added to drinking water in most U.S. water systems to help protect people’s teeth from decay. About 15,000 Hillsboro residents already receive fluoridated water from the Tualatin Valley Water District, which supplies areas east of Cornelius Pass Road and north of U.S. 26. But the remaining 92,000 city residents receive their water from the Hillsboro Water Department, which does not fluoridate the water.

Should Measure 34-338 pass, Hillsboro Water Department Director Niki Iverson said her agency would follow the non-binding guidance and fluoridate the rest of the city’s water supply, unless regulations change or costs skyrocket. The department would spread the anticipated costs of around $4 million over at least four to five years and delay non-urgent projects to avoid raising rates, Iverson said.

In addition to providing water to most Hillsboro residents, the department also serves the communities of Gaston and Cornelius.

Organizations including the Centers for Disease Control and Prevention consider fluoride safe at low concentrations, and in most of the U.S., it’s added to drinking water at a concentration of 0.7 milligrams per liter. A notable exception is the city of Portland, the largest city in the U.S. without fluoridated water.

Opponents of fluoridation point to a growing body of research showing that fluoride can have adverse effects on children’s IQ. And the Hillsboro vote is coming just as anti-fluoridation advocates notched a major win: A federal judge in San Francisco ruled Tuesday that the Environmental Protection Agency must further regulate fluoride in drinking water out of concerns about intellectual development.

In Mossman’s eyes, adding fluoride to Hillsboro’s water is crucial for the tooth health of local children, including her patients. Her advocacy group, Healthy Teeth Hillsboro, has raised about $6,500 to support the measure, campaign finance records show.

Last summer, Mossman saw two young children whose teeth had deteriorated to the point that their parents had to sell their car to pay for dental care. They lived less than a mile from homes that receive fluoridated water, she said. And if they’d lived across that border, she thinks their teeth wouldn’t have deteriorated so much.

“So I got fired up,” Mossman said. “I went to the City Council, and I said, ‘Please help me with this. There’s no reason Hillsboro should not be fluoridated.’”

To Mossman, opposing fluoridation is akin to embracing the anti-vaccine movement. Opponents of the measure, however, argue that fluoride poses too great a health risk to countenance.

“What level of hazardous material do we want to put into any water supply?” asked Hillsboro resident Matthew Sztelle, the director of advocacy group Clean Water Hillsboro, which has raised about $5,500 to oppose the measure.

Staci Whitman, a pediatric dentist in Portland who works with Hillsboro patients, agreed. She used to support fluoridation, but more than 10 years ago, she dove into the research and changed her mind. She no longer prescribes fluoride supplements for kids drinking non-fluoridated water, she said, because she doesn’t think the benefits of fluoride for teeth outweigh concerns that it could reduce children’s IQ.

“Brain health trumps teeth,” Whitman said.

No one disputes that at high concentrations, fluoride can have adverse health effects. High, sustained exposure can lead to skeletal fluorosis, a serious bone disease. And a recent meta-analysis by the federal government’s National Toxicology Program found an association between higher fluoride levels of 1.5 milligrams per liter or above and lower IQ. It noted, however, that it had insufficient data to draw conclusions about the impacts of drinking fluoridated water at 0.7 milligrams per liter.

Jessica Steier, a Massachusetts-based public health scientist and founder of the podcast Unbiased Science, pointed out that the government report looked at fluoride levels significantly higher than what’s added to the water in the U.S. She said she does not consider standard fluoridated water a cause for concern: “There is absolutely no reason to panic.”

But Ashley Malin, who researches the effect of fluoride exposure on neurodevelopmental outcomes at the University of Florida, said adverse effects can occur even at 0.7 milligrams of fluoride per liter. In particular, studies in areas with typical levels of water fluoridation have found associations between higher fluoride levels in pregnant women and lower IQ for their children, she said.

“There are growing concerns now, particularly about the impacts on child development,” Malin said. “People are becoming more cautious.”

Moreover, Malin said research generally shows that fluoride is best at preventing tooth decay when applied topically — for example, via a fluoridated toothpaste. She described the evidence for benefits from ingesting fluoride as weaker, though the American Dental Association supports the use of both topically applied and ingested fluoride. Steier said the data are mixed, but pointed to research, including a 2018 federal government-funded study, that showed ingesting fluoride does provide benefits for children.

Opponents of fluoridation in Hillsboro argue that taking fluoride should be a question of choice. If individual people want to use fluoride for tooth health, they should take supplements or use fluoride toothpaste rather than putting it in the entire city’s drinking water, said Sztelle of Clean Water Hillsboro.

But to Mossman, leaving fluoride out of the water supply poses an equity issue. Wealthy parents might be able to take their children to the dentist regularly and provide them with fluoride supplements, but lower-income parents working multiple jobs can’t always afford preventative dental care or ensure their kids have access to fluoride.

Fluoridation has a long history of contention in the Portland area. Portland voted to fluoridate in 1978 but overturned that vote two years later. In Washington County, Beaverton, Forest Grove and the Tualatin Valley Water District — minus the Metzger Water District — fluoridate their water.

Hillsboro, meanwhile, hasn’t voted on fluoridation since the 1950s. In 1952, residents voted in favor of adding fluoride before rejecting that decision in another vote just one year later. A community group pushed for fluoridation in 2002, but faced opposition. No vote took place then, Iverson said, and she’s not sure how public sentiment has shifted over the past 70 years.

“We don’t want to make a shift without really getting that information back from the community,” Iverson said.

— Aviva Bechky covers politics and education for The Oregonian/OregonLive. They can be reached at abechky@oregonian.com or on X at @avivabechky.

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