Is Fluoride dangerous?
The answer is an unequivocal; NO! Not in the concentration at which it is added and maintained in drinking water. Generally around 1 mg/l. In recent studies there is no evidence to demonstrate that it is harmful in any way. It is in fact; very helpful.
Here is the most important thing to understand about fluoride and/or any other mineral. At very high concentrations “all” minerals are harmful. A professor at Rutgers in a toxicology class explained to us that iron (Fe) is perhaps the most toxic mineral at very high concentrations. At concentrations that are lower than that at which fluoride becomes toxic. If you think about it logically, what happens when you ingest a little too much of an iron supplement? In many people it can cause severe constipation which will damage critical organs over time.
There are some water systems that need to remove fluoride from drinking water where it is naturally occurring at high levels (much like other minerals such as iron and manganese). Drinking water with high levels of fluoride (3 to 5 mg/l) can, over time, mottle teeth (discolour them). At very high levels (25 to 35 times the concentration in fluoridated drinking water) can be fatal. That is true of other minerals as well.
Much like all conspiracy theories that some people like to create and/or promote, the danger of approved levels of fluoride in drinking water is just another one of those.