TARPON SPRINGS — After nearly two hours of listening to impassioned pleas about the dental health of Tarpon residents, the City Commission unanimously voted Tuesday night to add fluoride to the city’s drinking water.

Commissioner Jeff Larsen, who asked for the discussion on fluoridation, said he came to his conclusion after asking if fluoride is “safe, effective and is it the city’s role to do this?”

“Yes, it’s safe … yes, it’s effective … and it is absolutely the right thing for us to do,” Larsen said after recounting the research he had done on each question.

In about two years, Tarpon Springs will begin supplying its own drinking water when it finishes building a $45 million water treatment plant. The reverse osmosis plant, which will pull brackish water from wells, has been delayed because Tarpon resident Henry Ross challenged the plant in court on environmental issues.

Now Ross has exhausted all his legal appeals, so the city can start building the water plant, City Manager Mark LeCouris said.

In 2008, a different set of Tarpon commissioners voted not to include fluoridation equipment in the plant’s design. It will cost $70,000 to add that, said Bob Robertson, Tarpon’s public services program manager.

Tarpon now purchases 80 percent of its water from Pinellas County. In December and after a contentious public debate, the county stopped adding fluoride to its drinking water, affecting some 700,000 residents. Opponents contended that the government had no right to add chemicals to the drinking water supply.

More recently, Dunedin, Pinellas Park and Plant City decided to keep fluoride in their public water supply.

Tuesday night, almost 25 people, including several dentists, spoke for or against adding fluoride. Many dental professionals say fluoride is safe and effective in fighting tooth decay.

City officials said Tarpon’s water naturally has some fluoride, but the city will add more to meet a federally recommended standard.

Before those in attendance were allowed to speak on the issue, Mayor David Archie told them that everyone’s opinion would be listened to and respected. He warned that shouting or clapping during speeches wouldn’t be tolerated. Every time people violated the rule, the mayor quickly put a stop to it.

Kurt Irmischer, president of Citizens for Safe Water, a political action committee based in Clearwater, argued that fluoride shouldn’t be added to Tarpon’s water. He said there is “not one” peer reviewed study that says “water fluoridation is safe and effective.”

But Dr. Kristen Allen, a Tarpon dentist, said fluoride in the water is helpful.

“Studies have shown it makes a huge difference in fighting tooth decay,” Allen said. “I hope we choose something better for our health and the health of our neighbors.”

Commissioner Susan Slattery, who seconded Larsen’s motion to add fluoride, said she made up her mind after listening to the comments.

“I came here this evening not knowing what side of the fence I was on,” Slattery said. “I wasn’t sure if we should add fluoride levels in our water. Part of our role is to look out for the general public and welfare of our citizens.”