The national Centers for Disease Control and Prevention has long recommended that people know how much fluoride is in their water.

To help people find out, it has a Web site, which was promoted last year by the South Carolina Department of Health and Environmental Control.

On Thursday, the CDC confirmed The Post and Courier’s finding that the Web site had incorrectly labeled some water systems as having the “optimal level” of fluoridation when in fact the site showed them to have unacceptably high levels of fluoride.

Indeed, every water system in South Carolina where the fluoride level was reported to be above 2 parts per million – the level at which the Environmental Protection Agency requires that customers be notified and the CDC recommends that young children don’t drink the water – was listed as having the optimal level of fluoride.

Kip Duchon, the CDC’s national fluoridation engineer, said the listings were a mistake.

He said that so few water systems, serving roughly half of one percent of the nation’s population, have fluoride levels above 2 ppm that any water system with enough fluoride to prevent cavities was listed on CDC’s site as having the optimal fluoride level.

“That’s not an excuse, because we should really do better than that,” he said. “I’ve been meaning to change that.”

The CDC recommended in a national 2001 study that “all persons should know whether the fluoride concentration in their primary source of drinking water is below optimal, optimal, or above optimal,” and the Web site was created as a way to help them find out.

The site, “My Water’s Fluoride,” is at:

The government says the ideal fluoride level is between .7 to 1.2 ppm.