WEST PALM BEACH — County Administrator Bob Weisman is recommending that Palm Beach County end fluoridation of the water supply in unincorporated areas outside cities, towns and villages.

In a memo Friday morning to the County Commission, which must make the ultimate decision, Weisman said that the “perceived dental benefits” may not sufficiently exceed the possible negative effects of fluoridation.

After reviewing the results of a recent National Research Council study on health effects of fluoride, Weisman said he concluded that the report “does raise sufficient evidence about potential negative health effects … to justify a decision to end fluoridation.”

His recommendation is bound to spark controversy when it comes before the County Commission on June 20. For years, fluoridation of the county’s water supply has been a highly emotional issue.

Public health advocates, led by county health director Dr. Jean Malecki, have vociferously argued the health benefits of fluoridation are enormous, the cost is cheap, and there are no known detriments from fluoride.

Anti-fluoride activists have raised concerns about a host of potential public health problems, including cancer and the effect of fluoride on the bones of seniors who have consumed fluoridated water for extended periods.

After long and contentious debate, the County Commission voted 5-2 in 2003 to buy the equipment to begin fluoridation. Fluoride began going into the county’s water supply early in 2005.

Weisman said his decision would mean the loss of the investment the county made in fluoridation equipment. At the time the decision was made, the cost was estimated at $600,000.

Weisman, a former director of the county water utility, said Friday he did not know the precise cost but estimated it in the “hundreds” of thousands of dollars.

Bevin Beaudet, the current utility director, was out of the office Friday morning. His assistant said the precise cost of the fluoride capital expense wasn’t immediately available.

A county decision does not affect most residents of cities, towns and villages, who get water from their own systems, most of which add fluoride. It would affect residents of unincorporated areas and a handful of cities whose residents get their water from the county system.