The chemical compound that was voted into our municipal water supply is not as they say naturally occurring but in fact is a residue from scrubbed smoke stacks of industrial plants. Most of the plant locations operate outside of the United States out of reach of EPA environmental controls. There are three types of additives that are currently in use in the United States, which are fluorosilicic acid, sodium fluorosilicate, and sodium flouoride. All three of these chemical compounds are commonly referred to as silicofluorides. According to the Centers for Disease Control (CDC), “Most fluoride additives used in the United States are produced from phosphorite rock. Phosphorite is used primarily in the manufacture of phosphate fertilizer” (CDC, n.d.).
Calcium fluoride is the chemical compound that we find occurs naturally in our environment. Its chemical makeup is quite different from silicofluorides which contain additional toxic pollutants like arsenic and heavy metals due to the manufacturing process of fertilizer production. In a comparative study between fluoride compounds the researchers found that silicofluorides were 85 times more toxic than naturally occurring calcium fluoride (Cammack et al, 1934). There is no scientific basis to which the comparison of silicofluorides with natural calcium fluoride is even appropriate or responsible.
EPA Letter by Rebecca Hamner, Deputy Assistant Administrator for Water states;
In regard to the use of fluosilicic acid as a source of fluoride for fluoridation, this Agency regards such use as an ideal environmental solution to a long-standing problem. By recovering by-product fluosilicic acid from fertilizer manufacturing, water and air pollution are minimized, and water utilities have a low-cost source of fluoride available to them. I hope this information adequately responds to your concern.
In other words if this product is released into the water or air it is considered pollution but it is okay to put it directly into municipal water supplies.
Cammack et al. (1934). Comparative toxicity of fluorine compounds. Ind. Eng. Chem. Retrieved from http://pubs.acs.org/doi/pdf/10.1021/ie50295a026
CDC. (n.d.). Water fluoridation additives. Department of Health and Human Services. Retrieved from http://www.cdc.gov/fluoridation/fact_sheets/engineering/wfadditives.htm