Fluoride is an element from the halogen group, as are iodide and chloride. It is commonly added to the water supply as hydrofluosilicic acid, silicofluoride or sodium fluoride. Fluoride is also found as an additive in toothpastes and some mouthwashes, as a tooth decay preventive ingredient.
Dr. William Marcus, believes that a study conducted by Battelle for the National Toxicology Program on the toxicology of fluoride shows that there were dose-related increases in bone cancer in male rats. Dr. Marcus also questions the removal by peer reviewers of cancers at other sites in the rats as well. Especially worrisome to Dr. Marcus is the fact that that levels of fluoride that caused the cancers in the rats were lower than those seen in humans who ingested lower amounts, but for a longer period. These levels are generated because fluoride is accumulated in the body and is not secreted.
Dr. Marcus was formerly the chief toxicologist for the EPA's Office of Drinking Water, but was fired in 1991 after insisting that an unbiased evaluation of fluoride's cancer potential be conducted. Marcus fought his dismissal, and was able to be reinstated after demonstrating in court that it was politically motivated