Tawny Leonard - Virtually any substance you can name – even those that are essential or beneficial at low levels of exposure – are toxic at high enough exposure levels.  Consider oxygen, water, sodium, potassium, chlorine, caffeine (on the EPA neurotoxin list), aspirin (salicylate on the EPA neurotoxin list), etc.  Every one of these substances will kill you if you ingest or breathe a high enough dose.  Simply claiming something is a poison or toxic out of any context is a perfect example of fear-mongering.

Over 70 years of research has demonstrated that community water fluoridation is a safe and effective public health initiative.  That is why over 100 national and international scientific and health organizations recognize the public health benefit of fluoridation.
ada(dot)org/en/public-programs/advocating-for-the-public/fluoride-and-fluoridation/fluoridation-facts/fluoridation-facts-compendium 
Ilikemyteeth(dot)org/fluoridation/why-fluoride/