Currently, I am traveling in Italy giving presentations on waste management. I have been forwarded a copy of your editorial ridiculing any notion that fluoridation could possibly cause any health problem and that practice is extremely effective at reducing tooth decay.

I will leave your councilors to judge the quality of the evidence that I will share with them on March 14. I write now because I am upset with the bullying tone you have adopted with one of your councilors, Amy Valentine. It is well known that if people are unable to answer a disturbing message they begin by attacking the messenger. You have chosen to do so in this case using the authority of local dentists, the American Dental Association and the Centers for Disease Control and Prevention. However, on this particular issue all these sources are highly suspect because of their very aggressive and long-term promotion of this practice.

It is simply not enough to parrot the phrase that fluoridation is "safe and effective" to win the case. It is incumbent on those who support this most unusual practice (what other chemical is added to the public water supply to treat people rather than treat the water?), which has been rejected by most industrial countries, to provide the scientific evidence for their claims.

To offset the 23 studies from India, Iran, Mexico and China which have shown that high doses of fluoride are associated with lowered IQ in children, where are the studies of the IQ of children living in Plattsburgh or any other fluoridated community in the U.S.? I am not aware of any. Why have they not been done?

The key question, of course, is whether there is an adequate margin of safety between the levels which have caused this harm in other countries and the levels experienced by children in this country drinking uncontrolled amounts of fluoridated water. The lowest level estimated at which IQ was lowered in one of these studies was 1.8 ppm (Xiang et al., 2003). Can you find a single toxicologist or pharmacologist who will tell you that offers an adequate margin of safety for all children exposed to fluoridated water at 1 ppm? For that matter, will they also tell you that there is an adequate margin of safety for all the other health effects discussed in the 507-page report by the National Research Council, "Fluoride in Drinking Water" published in March 2006? Three of the authors of that report don't think so and have stated so in public.

On the issue of effectiveness, where is the peer-reviewed, published, scientific evidence that the teeth of children in Plattsburgh are "sturdier" than children in non-fluoridated communities in the area? You have none — only anecdotal reports. In fact, a study commissioned by the N.Y. Department of Health, which examined tooth decay in third graders, found absolutely no relationship between tooth decay averaged by county and percentage of the county's population drinking fluoridated water! Meanwhile, the data collected by the World Health Organization shows no difference in tooth decay in 12 year-olds between fluoridated and non-fluoridated countries .

In my view adding fluoride — a known toxic substance — to the public drinking water at 250 times the level naturally present in mother's milk (0.004 ppm) is both reckless and foolish, especially now that even promoters of fluoridation like the CDC admit that fluoride works topically, not systemically, i.e. it works by acting on the surface of the tooth not from inside the body (CDC, 1999, 2001).

Not only did your editorial writer question my concerns about fluoride's ability to damage the brain, but he or she also questioned my suggestion that fluoride also damages the teeth. That's strange because the CDC has reported that 32 percent of American children have dental fluorosis, a mottling and discoloration of the teeth caused by ingesting fluoride before the permanent teeth have erupted.

While the largest proportion of children thus affected have the condition in its very mild form, over 3-4 percent of children have the condition in its moderate or severe forms, in which 100 percent of the enamel is affected. Moreover, while these enamel defects can be covered by expensive veneers (about $1,000 per tooth) the worrying aspect about this is that it is generally agreed that dental fluorosis is the first indication that the child's developing body has been over-exposed to fluoride.

Thus, the key question then becomes, while the fluoride is damaging the growing tooth by some systemic mechanism, what other tissues might it be damaging without this obvious and visible telltale sign? This underlines the significance of the IQ studies from countries which do not have a fluoridation program to protect.

So let's examine the science here, please, not just the reiteration of long-held beliefs.

Paul Connett, Ph.D., is professor emeritus of Environmental Chemistry, St. Lawrence University, Canton, and director of Fluoride Action Network.