The Greenville Water System has reduced the amount of fluoride in its drinking water to reflect new federal guidelines.

The move by the U.S. Environmental Protection Agency and the Department of Health and Human Services was based on new science which concluded that less fluoride is warranted because there are other sources of fluoride today.

The new guideline is 0.7 milligrams per liter of water, which replaces the previously recommended range of 0.7 to 1.2 milligrams.

Fluoride has been added to public water systems since the 1940s to prevent cavities, according to EPA.

But it hasn’t been without controversy.

A national consumer group called the Fluoride Action Network has been fighting fluoridation for years, saying that ingesting fluoride, as opposed to topical application on the teeth, “has little benefit but many risks” to human health.

Tara Blank, science and health liaison officer for the network, told GreenvilleOnline.com that the new level is still too high because there are so many other sources of fluoride, including toothpaste and other dental products, pesticides, pharmaceuticals and processed foods made with fluoridated water, so people may be getting too much of it.

“The position of the Fluoride Action Network is that a reduction in fluoride levels is not sufficient, and that the United States should follow the approach of Western Europe and end water fluoridation completely,” she said.

EPA, which is also reviewing the maximum amount of fluoride in drinking water, said the new level offers the benefits of preventing cavities, while reducing any negative health effects.

Among the risks, according to Blank’s group, are potential brain damage, thyroid suppression and increased risk of bone fracture. And the group says fluoridation’s cavity-reducing benefits have been exaggerated and that the same drops in tooth decay have been reported in all western countries, even those that never put fluoride in their water.

But Christine Veschusio, director of the Division of Oral Health at the state Department of Health and Environmental Control, says 66 years worth of scientific data show fluoridation to be safe and effective. She said research shows it’s resulted in a 20 percent to 40 percent reduction in tooth decay.

And K.C. Price, manager of water resources at Greenville Water System, which is following state and federal guidelines, said the American Dental Association and the U.S. Centers for Disease Control have endorsed fluoridation for years.

John Ferry, professor of chemistry and biochemistry at the University of South Carolina, said the new recommendation was based on a National Research Council review that said EPA should consider the other sources of fluoride when recommending drinking water levels.

People can get too much fluoride, he said. And that can result in a condition called fluorisis, or a permanent staining of the teeth, and brittle bones. But he said the levels found in drinking water are safe.

Blank said the fluoride most commonly used in drinking water is an industrial waste product of the phosphate fertilizer industry.

Ferry said many industrial byproducts can be purified into other products, such as artificial vanilla, which is from waste derived in paper processing.

“No one is going to willfully take on the liability of choosing a chemical they know is going to hurt people,” he said.