Boulder’s water board probably will reconsider keeping fluoride in the city’s water supply after Environmental Advisory Board heard more than a dozen residents debate its value Thursday.

There was no consensus about keeping or rejecting fluoride in drinking water, but everyone agreed the time is ripe for more public debate.

“It’s obvious that a lot of people feel strongly about this issue,” environmental board member Clay Fong said.

The Fort Collins Water Board recently recommended that the City Council stop fluoridating the water supply. The town of Erie has mailed a survey to residents asking whether fluoride should be put in the water. And Colorado Springs officials are addressing the issue.

Boulder residents voted 52 to 48 to add fluoride to the city’s water supply in 1969 at a rate of .9 milligrams per liter. The Centers for Disease Control and Prevention, American Dental Association and Colorado’s health department — among many other government agencies — recommend fluoride in the water supply to prevent tooth decay.

“There is not a more economic way to prevent tooth decay than adding fluoride to the water,” said Vince Cleeves, a Boulder dentist. “The main benefit of fluoride in the water is not the topical application, it’s the incorporation of fluoride into the tooth structure as it grows. Topical application will not do anything but affect the very surface of the tooth.”

Chuck Stout of Boulder County’s Health Department said adding fluoride to the water, and the resulting decline in tooth decay, is “one of the 10 most significant achievements of the 20th century.”

About 62 percent of the nation’s population has fluoride in their water supply, and the government’s goal is to have 90 percent of the drinking fluoridated water by 2010, Stout said.

But the value of adding fluoride to the water supply has been a continuing community debate, said Ned Williams, director of public works.

In 1999, a telephone survey of 400 Boulder residents found that 60 percent agreed or strongly agreed that the city should continue fluoridation, he said.

Several other residents and a dentist at the meeting said new research shows fluoride is not as safe as once believed and that fluoride is only effective if applied topically, like in toothpaste.

“The preponderance of evidence for fluoride was developed in the’40s and’50s,” said Stephen Koral, a dentist in Boulder. “And the preponderance of evidence against it developed in the’80s and’90s. We need to be open to change.”

Koral and several others said residents may be accumulating fluoride in their bodies now that food is processed in fluoridated water and people have been drinking it since they were children. They said some studies indicate fluoride can accumulate on the skeleton and weaken the bones.

“We are not talking about outlawing it,” said Alison Burchell of Boulder. “We are talking about giving people the choice … the right of informed choice.”