According
to the National Toxicology Program, "the
preponderance of evidence" from
laboratory 'in vitro' studies indicates that fluoride is
a mutagen (a compound that can cause genetic damage).
It is generally accepted that if a substance can induce genetic
damage there is a heightened risk that it could cause cancer
as well.
While the concentrations of fluoride causing mutagenic damage
in the in vitro studies is higher than the concentrations
found in human blood, there are certain "microenvironments"
in the body (e.g. the bones)
where the concentrations of fluoride can accumulate
to levels comparable to, or in excess of, those causing mutagenic
effects in the laboratory.
Of particular concern are a series of studies indicating that
fluoride can cause osteosarcoma
(bone cancer) in both fluoride-treated
male rats and boys under the
age of 20 living in fluoridated areas. Osteosarcoma is a
rare, but deadly, form of cancer that strikes primarily during
the teenage years.
Of additional concern are recent studies indicating that: