http://www.livescience.com/38952-epa-arsenic-petition-response.html
That's literally infinitesimal. The sunlight from walking outside to your car to go to dentist is probably more likely to give you cancer than current levels of fluoride in water.
just playing devil's advocate: how can those numbers, or any numbers, be reliable in terms of science? how are they going to isolate the variables in order to say definitively that fluoride caused cancer in x amount of patients diagnosed with cancer in america? even in a health.gov review of fluoride vs cancer it notes that:
There have been over 50 human epidemiology studies of the relationship between water fluoridation and cancer. Epidemiological studies of fluoride usually attempt to identify statistical associations between cancer rates and county- or city-wide patterns of water fluoridation. Expert panels which reviewed this international body of literature agree that there is no credible evidence of an association between either natural fluoride or adjusted fluoride in drinking water and human cancer (LARC, 1982; Knox, 1985). Interpretation of these studies is limited by the inability to measure individual fluoride exposures or to measure other individual predictors of cancer risk, such as smoking or occupational exposures.
It does largely claim little to no link at all with rats over a 2 year dosed study and some other cases as well but at the end of the day

Some credible medical journals have added it as a neuro-toxin that link it to autism, adhd etc and in that same .gov article it states that:
Fluoride has been used for nearly 30 years as an experimental therapy to treat osteoporosis, but has only recently been evaluated in controlled clinical trials. Two new U.S. clinical trials showed no significant reduction in the rates of bone fractures related to the administration of fluoride. An FDA advisory panel has concluded that fluoride therapy has not been shown to be effective in reducing the frequency of vertebral fractures.
Using the crutch of experiments/cases being difficult to isolate in order to disprove myths of fluoride benefits can also be used conversely, granted...but even studies on tooth decay and cavities are inconclusive.. so i applaud the fed for cutting back on fluoridation levels in tap water since it is an unknown in terms of benefits/downfalls and it can still be attained via the aforementioned alternatives if people so choose




. be a man.