Quote:
Does drinking optimally fluoridated water cause or ac-
celerate the growth of cancer?
Answer.
According to generally accepted scientific knowledge,
there is no association between cancer rates in humans
and optimal levels of fluoride in drinking water.
Since community water fluoridation was introduced in
1945, more than 50 epidemiologic studies in different
populations and at different times have failed to dem-
onstrate an association between fluoridation and the
risk of cancer. Studies have been conducted in the
United States, Japan, the United Kingdom,
Canada and Australia. In addition, several indepen-
dent bodies have conducted extensive reviews of the
scientific literature and concluded that there is no rela-
tionship between fluoridation and cancer.The U.S. Environmental Protection Agency (EPA) further commented on the safety of appropriate fluoride exposure in the December 5, 1997, Federal Register. 29. “...the weight of evidence from more than 50 epidemiological studies does not support the hypothesis of an association between fluoride exposure and increased cancer risk in humans. The EPA is in agreement with the conclusions reached by the National Academy of Sciences (NAS).”
Despite the abundance of scientific evidence to the
contrary, claims of a link between fluoridation and increased cancer rates continue. This assertion is largely based on one study comparing cancer death rates in ten large fluoridated cities versus ten large nonfluoridated cities in the United States. The results of this study have been refuted by a number of organizations and researchers. Scientists at the National Cancer Institute analyzed the same data and found that the original investigators failed to adjust their findings for variables, such as age gender differences, that affect cancer rates. A review by other researchers pointed to further shortcomings in the study. The level of industrialization in the fluoridated cities was much higher than the nonfluoridated cities. Researchers noted that a higher level of industrialization is usually accompanied by a higher incidence of cancer. While the researchers noted that the fluoridated cities did have higher cancer rates over the twenty year study, the rate of increase in the nonfluoridated cities was exactly the same (15%) as the fluoridated cities. Following further reviews of the study, the consensus of the scientific community continues to support the conclusion that the incidence of cancer is unrelated to the introduction and duration of water fluoridation.
In the early 1990's, two studies using higher than optimal levels of fluoride were conducted to evaluate the carcinogenicity of sodium fluoride in laboratory animals. The first study was conducted by the National Toxicology Program (NTP) of the National Institute of Environmental Health Sciences. The second study was sponsored by the Proctor and Gamble Company. In both studies, higher than optimal concentrations of sodium fluoride (25, 100, and 175 ppm) were consumed by rats and mice. When the NTP and the Proctor and Gamble studies were combined, a total of eight individual sex/species groups became available for analysis. Seven of these groups shows no significant evidence of malignant tumor formation. One group, male rats from the NTP study, showed "equivocal" evidence of carcinogenicity, which is defined by NTP as a marginal increase in neoplasms - i.e., osteosarcomas (malignant tumors of the bone) - that may be chemically related. The Ad Hoc Subcommittee on Fluoride of the U.S. Public Health Service combined the results of the two studies and stated: "Taken together, the two animal studies available at this time fail to establish an association between fluoride and cancer."
It goes on and on, also mentioning good, old-fashioned fluoride toxicity as false. According to the ADA, it is 
