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Legal tussle over fluoride in US tap water and link to IQ

A US courtroom is the battleground for a scientific clash between experts over a report suggesting fluoride can affect brain development, and whether the US Environmental Protection Agency (EPA) should ban this mineral in drinking water to protect foetuses and children from the risk of neurodevelopmental problems.

The case, being heard in a San Francisco district court, “is precedent-setting”, says Lynn Bergeson, a managing partner of Bergeson & Campbell who focuses on chemical toxicity. Rarely have judges had to “manage the enormity of this record of scientific evidence. … That’s why there’s a lot of attention focused on this.”

Adding fluoride to drinking water lessens tooth decay in children and adults by 25%, reports the journal Science. The Centres for Disease Control and Prevention (CDC) calls fluoridation, which began in 1946 in the United States and is decided by local water districts, one of 10 “great public health achievements” of the 20th century.

But from the start, some activist groups were worried about potential harm. And over the past few decades, studies of laboratory animals and of communities where drinking water naturally contains fluoride have hinted that high levels might affect brain development.

The current case has put the spotlight on an unpublished assessment by the federal government’s National Toxicology Programme (NTP). It reported “moderate confidence” that drinking water containing fluoride at levels at least twice as high as those recommended by the federal government is associated with lower IQ in children.

The Fluoride Action Network (FAN) and other groups argue that such data indicate the EPA should be regulating fluoride under the Toxic Substances Control Act (TSCA).

This week’s testimony marked the resumption, after a years-long pause, of litigation that began in 2017. Over nine days, Judge Edward Chen of the US District Court for the Northern District of California is scheduled to hear the views of seven experts on a range of technical topics, including whether there is a safe threshold for fluoride exposure.

During opening arguments last month, the attorney for the plaintiffs, Michael Connett, highlighted babies who were fed formula made with tap water as a “critical vulnerable group being exposed to the highest dose of fluoride of any age group in the population … and a major cause for concern”.

He argued that if the EPA was aware of a different compound that posed a similar potential threat to newborns, the agency wouldn’t hesitate to regulate it.

The EPA and others say there is little strong evidence that the current recommended concentration of fluoride in drinking water – 0.7mg per litre – poses a threat. (That level is set to avoid discolouration of teeth in children.)

“The dose makes the poison,” said Paul Caintic, a Department of Justice attorney. “Given the current state of science, the court cannot conclude that community water fluoridation presents an unreasonable risk.”

The fluoride lawsuit is the first to reach trial under a 2016 TSCA provision allowing citizens to ask a court to assess a chemical’s risk. FAN turned to that strategy after the EPA said its request that the agency ban fluoridation lacked a “scientifically defensible basis”.

The trial began in June 2020 but Chen suspended it months later to wait for publication of the NTP report. That assessment, based on work conducted by NTP experts from 2016 to 2019, initially classified fluoride as a cognitive developmental hazard.

But NTP removed that determination after two reviews by the National Academies of Sciences, Engineering and Medicine in 2020 and 2021 found the evidence was lacking. One flaw, the reviews said, was that the assessment didn’t focus on how people respond to various doses of fluoride.

The report has yet to be formally released, and FAN charges that the repeated reviews have been designed to delay it – a critique supported by some scientists and former NTP leaders.

According to emails released to FAN under the Freedom of Information Act, a senior official at the Department of Health and Human Services intervened in 2022 to halt publication just days before the report was scheduled to be released.

But in March 2023, as a result of litigation, NTP did release a 393-page draft. And last May, NTP’s science advisory board signed off on the report and sent it to NTP leadership.

Dental health advocates say activists are already spinning the report to their advantage by claiming NTP found no safe dose (a claim not directly stated in the report). The American Dental Association has strongly urged NTP to add a disclaimer to the report highlighting its scientific limitations.

In the meantime, Chen has allowed the lawsuit to resume. He has suggested the EPA must regulate fluoride if FAN proves that fluoride poses an “unreasonable risk” to pregnant women and children. Under TSCA, the EPA cannot consider a chemical’s benefits, such as oral health.

Lynn Goldman, an epidemiologist at George Washington University and former EPA official, doubts that Chen will order EPA to ban fluoride in drinking water.

“I can’t imagine a court coming back and saying, ‘You did a risk assessment wrong, and here’s how you should have done it,’” she says. But the court might order the EPA to consider fluoride as a toxic substance under TSCA and make it a high priority for a new evaluation to establish safe exposure limits.


Science article – Does fluoride in drinking water lower IQ? Question looms large in court battle (Open access)


See more from MedicalBrief archives:


Fluoride study raises public health concerns


Experts call for more water fluoridation to fight tooth decay


UK water fluoridation report dismisses claims of health danger


US panel recommends fluoride varnish for infants









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