If there is one piece of scientific literacy that I wish the entire world had, it was the concept that toxicity is a function of dose. Yes, fluoride is toxic.

If there is one piece of scientific literacy that I wish the entire world had, it was the concept that toxicity is a function of dose. Yes, fluoride is toxic. The EPA limit for fluoride is 4ppm, and that is probably too high (something like 2ppm would work better). There are parts of the country where the natural incidence of fluoride in groundwater is in excess of 4ppm, and therefore defluoridation needs to be done. Fluoridation of drinking water is done to a standard of 0.5-0.75 ppm (US Public Health Service specifically recommends 0.7). Most of the country lives in places where the natural ground water concentration of fluoride is below this level, and thus fluoridation is necessary to reach the recommended level.