Ask the EPA to change the source of fluoride added to U.S. drinking water.
Currently, the source of fluoride in most public water supplies is fluorosilicic acid, according to government records. The petition calls for the EPA to instead require the use of pharmaceutical-grade sodium fluoride in water fluoridation, which is the addition of fluoride to drinking water for the purpose of preventing cavities.
Fluorosilicic acid is often contaminated with arsenic, and recent research has linked the arsenic from fluorosilicic acid in drinking water to as many as 1,800 extra cases of cancer yearly in the United States, said William Hirzy, a chemistry researcher American University in Washington, D.C. Hirzy, who worked at the EPA for 27 years, submitted the petition.
The study and petition grew out of what researchers believe is a lack of regulation and understanding of chemicals used in fluoridation, Hirzy said. Fluorosilicic acid has been shown to contain the carcinogens arsenic and lead, and to leach lead from water pipes, he said.
Billions in cancer costs
In the study, published in February in the journal Environmental Science and Policy, Hirzy and co-authors estimated that putting pharmaceutical-grade sodium fluoride into the water supply would reduce the amount of arsenic in drinking water by 99 percent. The arsenic at issue is the inorganic variety, a known human carcinogen, meaning it causes cancer. [Why Is Arsenic Bad for You?]
The switch would cost $100 million, but would save billions in reduced cancer costs, Hirzy said.
"We found that the United States as a society is spending, conservatively speaking, $1 billion to $6 billion treating the excess bladder and lung cancers caused by arsenic in the most commonly used fluoridation chemical, fluorosilicic acid," Hirzy said.
The EPA limits levels of arsenic in drinking water to 10 parts per billion. Hirzy said that the researchers, in calculating the number of U.S. cancer cases yearly linked with arsenic in fluorosilicic acid, used the EPA's own risk assessment data.
Experts not involved with Hirzy's study agreed with its findings.