A landmark federal lawsuit that went to trial this week in California could change the longstanding practice of adding fluoride to the drinking water supplies for 200 million Americans.

The lawsuit, brought against the Environmental Protection Agency by groups including the Fluoride Action Network, Food and Water Watch and Moms Against Fluoridation, would compel the agency to require local water utilities to stop adding fluoride to tap water.

The suit claims fluoridated drinking water presents an unreasonable risk to public health and can harm the developing brain of young children and babies, causing an IQ deficit. Renowned public health experts, such as Dr. Philippe Grandjean of the Harvard T.H. Chan School of Public Health, have raised concerns about fluoride neurotoxicity and questioned the safety of fluoride-contaminated drinking water.

The U.S. first began adding fluoride to drinking water in the 1940s in an attempt to combat widespread tooth decay.

In 2011, responding to a lawsuit by Fluoride Action Network, EWG and Beyond Pesticides, the Department of Health and Human Services recommended that water utilities reduce the amount of fluoride added to tap water by almost half, from 1.2 parts per million, or ppm, to 0.7 ppm. This new recommendation took effect in 2015.

The levels of fluoride added to tap water supplies can vary, but the Centers for Disease Control and Prevention has established 0.7 ppm as a health advisory limit. EWG analysis of test data for community water systems across the country found roughly 30 million Americans are likely drinking water with fluoride levels higher than the CDC’s recommendation, as the news site Fair Warning reported Monday.

The CDC says if infant formula is mixed with fluoridated water, the baby’s teeth might be affected by dental fluorosis, which appears as white spot markings on the teeth. EWG recommends that baby formula be mixed with fluoride-free water, especially for an infant whose diet consists exclusively of powdered baby formula.

Excess fluoride exposure poses health risks, including discolored teeth, changes in the bones, and harm to the brain and nervous system. In 2017, a groundbreaking study by a team of researchers in Mexico found that exposure to fluoride during pregnancy can harm IQ and cognitive development in children. Similar results were found in a recent Canadian study.

The case is being argued before federal District Court Judge Edward M. Chen under the Toxic Substances Control Act, which gives the EPA the authority to limit or ban toxic chemicals in the nation’s municipal drinking water supply.

*Original article online at https://www.ewg.org/news-and-analysis/2020/06/federal-lawsuit-could-limit-fluoride-drinking-water