This is what Fluoride does to Concrete (it prevents cavities too)

...A recent chemical spill at a water treatment facility in Rock Island, Ill., required the assistance of an emergency relief crew decked in the very same type of hazmat suits being worn by workers at the Fukushima Dai-Ichi nuclear plant in Japan. Except instead of radiation, the leaked chemical at the water plant was actually hydrofluorosilicic acid, a chemical fluoride component commonly added to drinking supplies for the stated purpose of preventing cavities. This fluoride chemical is so hazardous that it actually began to burn through parking lot cement in Rock Island before emergency crews arrived on the scene.

According to reports from WQAD News 8 in Moline, a tanker truck delivering the fluoride began to overflow, leaking the chemical directly onto the parking lot where it spilled down towards the street. And before emergency crews arrived on the scene in full hazmat suits and gas masks, the fluoride had actually begun to burn a hole right through the concrete.

Learn more: http://www.naturalnews.com/031892_fluoride_corrosive.html#ixzz1I7CQptKW