TOPEKA, Kan. — Kansas legislators killed a proposal Monday that sought to undercut public support for adding fluoride to public water supplies.

The House Health and Human Services Committee voted 10-2 to table a bill that would have required cities and other local governments to warn consumers if their water is fluoridated. The bill can’t be considered again unless a majority of committee members want to debate it, which “in essence kills the bill,” said the committee’s chairman, Augusta Republican Rep. David Crum.

The most vocal supporter has been Mark Gietzen, an anti-fluoride activist from Wichita, a city that does not fluoridate its water and rejected a proposal in 2012 to do so. He said he will now push for the Senate to take up the issue.

“We had leaded gasoline for so long and didn’t think it was harming us,” he said. “Now it’s banned.”

But public health officials and groups condemned the bill, saying it was based on flawed science and would threaten public support for a longstanding practice that has greatly reduced tooth decay. The federal Centers for Disease Control last year called fluoridation of water “one of 10 great public health achievements of the 20th century.”

Nationally, the CDC said, nearly 75 percent of Americans live in communities with fluoridated water. The practice started in Grand Rapids, Mich., in 1945.

“There’s a consensus that there are overwhelming benefits from water fluoridation,” said Dr. Howard Pollick, a dentist and health sciences clinical professor at the University of California, San Francisco, who serves as the American Dental Association’s spokesman on fluoridation issues.

The bill called fluoride “a known toxic substance” and sought to require public water supplies to distribute a statement to their customers saying that ingesting fluoride lowers children’s IQs. Pollick said that while anti-fluoridation proposals have arisen in various places, Kansas’ appears to be the first requiring warning tied to children’s IQs.

Opponents of fluoridation point to a 2012 Harvard University review of 27 studies, mostly from China, concluding that fluoride may adversely affect children’s intellectual development. But public health officials have noted that the studies generally dealt with fluoride levels in water far exceeding the amount in U.S. water supplies, and the deans of the Harvard medical and dental schools publicly expressed support for fluoridation last year.

“I just don’t think the folks who oppose fluoridated water made the case, scientifically,” Crum said.