A House committee Wednesday approved Senate-passed legislation that would require most of Louisiana to add fluoride to public water supplies.

Senate Bill 312, which passed the House Health and Welfare Committee without opposition, would require water systems with at least 5,000 hook-ups to estimate how much it would cost for the necessary equipment. Once money is found through grants and state budget spending, the systems would then be required to install equipment to mix fluoride with water.

Dionne Richardson, the state dental director, said she hopes that the legislation would lead to 75 percent of the state’s population having access to fluoridated water. About 67 percent of the state’s population drinks water that has no fluoride added.

Fluoride is a chemical compound found naturally in ground water that helps fight tooth decay.

Adding it to the public water supply has been the source of much controversy over the past half century, including claims in the 1950s by the right-wing John Birch Society that the idea was inspired by communists.

Opponents these days question tests and point to instances in which equipment failed, causing people to ingest too much fluoride.

Fluoride Action Network, a nonprofit organization based in Canton, N.Y., argues in its literature that fluoride is most effective when used topically, as in toothpaste, and that there is evidence that shows the systemic intake of fluoride has been linked to risk of bone fractures, decreased thyroid function, lowered intelligence, arthritic-like conditions, and it can pit the enamel on teeth.

Nobody testified in opposition to the legislation in the House committee. It passed out of the Senate May 6 without a no vote being cast. It next goes to the House floor for consideration.

SB312 was amended to allow local communities to vote on opting out of the mandate if 15 percent of the community signs a petition.

“Historically, it has been very controversial,” said Ward Blackwell, executive director of the Louisiana Dental Association. “But for the most part we have not run into significant opposition on safety issues. We’ve heard about economic issues but not safety issues.”

For instance, unlike New Orleans, which gets its drinking water from one intake on the Mississippi River, Baton Rouge gets its water from an underground aquifer using about 50 wells and therefore would need a lot more equipment, he said. That increases the costs significantly, Blackwell said.

The average cost for a community to fluoridate its water is estimated to range from 50 cents a year per person in large communities to $3 a year per person in small communities, according to a study by the Centers for Disease Control and Prevention, called CDC.

Reviewing Medicaid statistics, the state Department of Health and Hospitals determined that preschool children not using fluoridated water cost taxpayers $36.28 more for medical and dental care than children who did drink the treated water. Those children were three times more likely to receive dental treatment in a hospital than children using fluoride.

Medicaid is a government program subsidized by federal and state tax dollars to provide health care for the poor, elderly and uninsured — roughly one-fourth of the state’s population