In a pivotal decision that could impact the decades-long practice of water fluoridation in the United States, a federal judge has ruled that current fluoride levels in drinking water pose an “unreasonable risk” to people’s health. This ruling, issued by Judge Edward Chen of the U.S. District Court for the Northern District of California, mandates the U.S. Environmental Protection Agency (EPA) to take regulatory action in response.
The court highlighted that fluoride in drinking water impacts “nearly all Americans.” Most people consume water treated at the long-recommended optimal level of 0.7 milligrams per liter (mg/L). However, Judge Chen’s ruling, backed by compelling scientific evidence, indicates that this level of fluoride exposure may pose serious health risks, especially for pregnant women and young children.
Challenging Official Orthodoxy
The ruling challenges long-held positions by public health organizations. Those include Centers for Disease Control and Prevention (CDC) and professional groups such as the American Academy of Pediatrics (AAP) and American Dental Association (ADA). These entities promote water fluoridation as a vital public health achievement. Despite growing scientific concerns, they have been defending the safety of fluoride, citing its role in preventing dental caries.
Judge Chen highlighted that scientific research now clearly points to fluoride’s potential neurotoxic effects. These effects are especially concerning for the developing brains of infants and young children.
The judge wrote:
Plaintiffs have proven, by a preponderance of the evidence, that water fluoridation at the level of 0.7 mg/L — the prescribed optimal level of fluoridation in the United States — presents an “unreasonable risk of injury to health or the environment, without consideration of costs or other non-risk factors, including an unreasonable risk to a potentially exposed or susceptible subpopulation under the conditions of use.”
The decision follows years of legal proceedings initiated by environmental and consumer advocacy groups, including the Fluoride Action Network, which sought a review under the Toxic Substances Control Act (TSCA).
Fluoride’s Impact on Children’s IQ
Key evidence in the ruling came from the National Toxicology Program (NTP) under the U.S. Department of Health and Human Services. The NTP systematically reviewed the research and identified a significant link between fluoride exposure and reduced IQ in children. Their findings showed that even fluoride levels as low as 1.5 mg/L could pose health risks.
In light of this evidence, Judge Chen rejected the EPA’s defense, which claimed that the threshold for fluoride toxicity was “not entirely clear.” Chen found this argument unconvincing. He emphasized that fluoride exposure in U.S. drinking water is dangerously close to levels known to cause harm.
He maintained,
In all, there is substantial and scientifically credible evidence establishing that fluoride poses a risk to human health; it is associated with a reduction in the IQ of children and is hazardous at dosages that are far too close to fluoride levels in the drinking water of the United States.
Chen further underlined that a reduction in IQ can have significant consequences. Research links even a small decrease of one or two IQ points to lower educational achievement, diminished employment opportunities, reduced productivity, and decreased earnings. The EPA itself acknowledges that IQ reduction poses a serious public health concern for communities.
Pregnant Women
According to the ruling, pregnant women across the country are already exposed to fluoride concentrations that exceed the hazard threshold established by scientific research. Chen maintains,
The pooled benchmark dose analysis concluded that a 1-point drop in IQ of a child is to be expected for each 0.28 mg/L of fluoride in a pregnant mother’s urine. This is highly concerning, because maternal urinary fluoride levels for pregnant mothers in the United States range from 0.8 mg/L at the median and 1.89 mg/L depending upon the degree of exposure. [Emphasis in original.]
Citing the latest research, the judge noted that the “optimal” fluoridation level of 0.7 mg/L in U.S. drinking water is almost twice the safe limit of 0.4 mg/L for pregnant women and their children.
Implications for U.S. Drinking Water
The EPA is now obligated to respond, though it retains discretion on the specific actions it may take. Possible responses range from issuing public warnings to outright banning the use of fluoride in drinking water. In addition, this decision highlights other areas where fluoride exposure could pose issues, such as regions with naturally high fluoride concentrations in groundwater. Furthermore, it raises concerns about fluoride intake from sources such as toothpaste.
Decades of Controversy and the Future of Fluoridation
For more than 70 years, U.S. public health officials have promoted water fluoridation as a key strategy for improving dental health. In 1962, the U.S. Public Health Service (PHS) advised community water systems to add fluoride to drinking water to prevent tooth decay. By 1975, the EPA recommended an optimal fluoride level of 1.2 mg/L, while also setting a maximum limit of 4 mg/L. This aimed to balance the dental benefits of fluoride with safety concerns.
However, as research increasingly revealed the potential adverse health effects of fluoride, Surgeon General Vivek Murthy lowered the recommended level in 2015. The new guideline reduced the range from 0.7-1.2 mg/L to a consistent 0.7 mg/L.
This recent ruling, though, challenges the long-standing endorsement of fluoride. It raises serious concerns about the safety of a practice once hailed as a major public health achievement. The plaintiffs’ victory also marks the first time a lawsuit under the amended Toxic Substances Control Act (TSCA) has reached federal trial. This sets an important precedent for future public-health challenges related to chemical exposure.
As the EPA evaluates its next steps, the decision has sparked a renewed debate over fluoride. It carries significant implications for public-health policy and the millions of Americans who consume fluoridated water.
What’s Next?
The EPA is expected to appeal the ruling. However, it faces a growing body of evidence that highlights the need for regulatory reform. The court’s decision also sets a major precedent. It opens the door for other citizen-led petitions to challenge long-standing environmental policies under the TSCA framework. This could influence future rulings on chemical safety in consumer products and the environment.
The recent publication of the NTP’s long-delayed research on fluoride’s neurotoxic risks adds to the debate. Both the scientific and regulatory communities will likely continue to grapple with the broader implications of fluoride exposure.
However, it must be remembered that, in spite of the documented dangers of adding fluoride to water systems, the issue is properly a matter for local authorities — not the EPA.
