On Tuesday a federal court in California found that fluoridation of water at 0.7 milligram per liter "poses an unreasonable risk of reduced IQ in children".

The new ruling issued by Judge Edward Chen noted that the finding does not "conclude with certainty" that fluoridated water is "injurious to public health" but does find there is "an unreasonable risk of such injury". This risk is sufficient to require the EPA to enact a regulatory response, Chen wrote.

The decision is the latest ruling in an eight-year legal battle between the U.S. Environmental Protection Agency (EPA) and the Fluoride Action Network (FAN). The lawsuit began following the EPA's 2016 decision to deny the plaintiff's petition under the Toxic Substances Control Act (TSCA). The first phase of the trial took place in summer 2020 via Zoom and the second phase of the fluoride lawsuit concluded in February in San Francisco.

While Judge Chen does not tell the EPA what the response to the ruling should be, he did rule that the EPA cannot ignore the risk.

The EPA must now initiate a rulemaking process to determine what regulation they will implement to lower or eliminate the risk posed by water fluoridation. The EPA is likely to appeal the decision, but could also drag out the rulemaking process for years.

The Fluoride Action Network believes the most effective way to eliminate this risk is to end water fluoridation and ban the practice altogether.

"In our view, attempts by the EPA to appeal or delay this ruling will only result in harm to hundreds of thousands of additional children, particularly those whose families are unable to afford expensive reverse osmosis or distillation filtration of their tap water," wrote Stuart Cooper, Executive Director for the Fluoride Action Network.