Phoenix will not remove fluoride from the drinking water of 1.4 million residents, a subcommittee of City Council members decided Tuesday.

After nearly two hours of heated testimony from advocates on both sides of the debate, council members agreed to let their fluoride policy stand without taking a vote. They could have opted to send the issue to the full council.

Councilwoman Thelda Williams, who moved to maintain the practice, said the medical community has provided sufficient evidence to show that adding fluoride to water has a public-health benefit. She dismissed claims that it lowers IQ levels in children.

“I just feel very strongly that I think what we’re doing is the right thing to do,” Williams said. “I think public health is the responsibility of government.”

Phoenix had been re-evaluating fluoridation for the first time since the City Council voted in 1989 to add the compound to its water system. Several members said the issue needed a second look in light of new science and to determine if it’s still a wise investment.

Council members on Tuesday appeared to agree that fluoride improves residents’ overall health by preventing tooth decay, taking the advice of city staff and the directors of the county and state public-health departments. The subcommittee included Williams and Councilmen Michael Johnson, Jim Waring and Daniel Valenzuela.

However, Waring asked staff to look further into what the city spends on fluoride compared with other municipalities. Phoenix spends about $582,000 per year on fluoride — about 39 cents per resident.

Opponents of fluoridation constituted much of the audience at Tuesday’s meeting, which often got heated as they shouted claims that fluoride is dangerous or has been used by governments to poison their people. Critics say studies have linked fluoridation to thyroid and neurological disorders, among other problems.

William Hirzy, a chemistry professor at American University in Washington, D.C., testified against fluoridation, saying that Phoenix uses a form of fluoride equivalent to toxic waste. At one point, Hirzy seemed to suggest that the federal government began promoting fluoridation decades ago to protect defense contractors who spilled it into water.

“There’s a lot of reputations on the line,” he said, citing studies stating fluoride does not prevent cavities. “If you dig into the facts, it always goes one way: People who were for fluoridation jump ship.”

Public-health administrators and dentists spoke in favor of continuing fluoridation, saying the overwhelming majority of scientific studies support their position. The Centers for Disease Control and Prevention and American Dental Association both endorse the practice.

Advocates of fluoridation do acknowledge one possible side effect: dental fluorosis, a condition in which the enamel of teeth becomes discolored or mottled when young children get too much fluoride. But they say the condition is merely cosmetic.

Fluoride is naturally found in water supplies, including those in the Valley. State health officials say Phoenix is merely supplementing its fluoride to increase it to an optimal level.

Dr. Bob England, director of the Maricopa County Department of Public Health, said studies have shown that fluoride decreases tooth decay by about 25 percent, especially in low-income areas where residents cannot afford dental care. He said no “credible, scientific sources” have found any serious side effects.

“It is easy to cherry-pick a particular piece of information here or there and try to make a point with it,” England said. “When you’re making decisions about issues like this, you need to look at the entire picture.”