SHREWSBURY – A local environmentalist who unsuccessfully tried to persuade the town to stop putting fluoride, the cavity-fighting naturally occurring chemical, in drinking water went before selectmen Tuesday night to explain his latest attempt.

Town meeting in October 2015 soundly defeated an article petitioned by Bryan R. Moss, of 16 Ruthen Circle, that would have discontinued the 63-year-old practice of fluoridating the local water supply.

This time around, Moss, a Precinct 8 town meeting member, has a petitioned article for the Sept. 26 special town meeting that focuses on whether the town has the legal right “to add any substance to the public drinking water supply for preventive health care purposes unrelated to contamination of drinking water.” It does not specifically mention fluoride.

Moss said his article, entitled Safe Drinking Water Protection bylaw, resembles the intent of the Safe Drinking Water Act that prohibits any national drinking water regulation to require the addition of such substances. The state Department of Environmental Protection also leaves it up to the local authorities.

Moss said he learned from last year’s town meeting experience that a lot of people in town approve of fluoride. But, its presence in the public water system violates the principle of informed consent and there’s no control over who gets it and how much. The petition was signed by 120 registered voters to get the article on the town warrant.

“I want to bring this back and say, ‘let’s talk about the pros and cons (of fluoride),’ but in the end who has the right to make the decision of what we put in our bodies. Is it an individual or is it” town government, said Moss.

He said there are many sources of fluoride, including in tooth paste and mouth wash, that people can get if they choose. For some, fluoride has adverse effects, including thyroid problems, according to some studies, he said.

Selectman Moira E. Miller said the studies she has seen support fluoride in water. The federal and state governments are not saying take it out, but that they are leaving it up to the local government where it should be. Most people in town for the past 63 years believe they have benefited from fluoridated drinking water.

“They know it’s in the water … I believe it is informed consent. They know it’s in the water. They can filter their water …,” she pointed out. “I just don’t see a case being made yet…”

Jeffrey W. Howland , the town engineer, said he’s concerned that the wording of the article, if passed, would prohibit the addition of any chemical, including those to regulate pH, corrosion and manganese, the source of discolored water this summer.