Marin residents opposed to the fluoridation of drinking water are urging their supporters to turn out for Tuesday’s meeting of the Marin Municipal Water District board, and board member Larry Bragman, who is sympathetic to their cause, says he will raise the issue.

“I don’t think that fluoride is necessary,” Bragman said. “In this day and age, the market provides so many fluoride products that there is really no need for it to be added to municipal systems anymore. I think it is a matter of consumer choice to begin with. I don’t think it needs to be mandated.”

The matter will come up when the board votes on whether to approve a purchase of chemicals for fluoridation and other purposes, which it does periodically.

Fluoridation opponents have been circulating an email with talking points, and the names and contact information for all of the board members.

“I’ve gotten a slew of emails,” said district board member Jack Gibson.

“As long as I’ve been on the board, this issue of fluoride has come up periodically,” said Gibson, who joined the board in 1995. “We have had many informational meetings on fluoride to talk it through with people. About six months ago we went through the same process. Why all of sudden it’s come back now is a little bit of a mystery to me.”

The fluoridation debate has raged nationally on and off since the 1940s. By the late 1960s opponents of fluoridation had become marginalized, associated with the John Birch Society. They were satirized in movies such as “Dr. Strangelove,” in which the mad Gen. Jack Ripper obsesses about the pollution of his precious body fluids.

“Unfortunately, there is still a stigma attached to questioning the wisdom of fluoride,” Bragman said. “Historically, the politics have been outlier politics, but I think the science has caught up to it. There have been some new studies that raise some real concerns about fluoride.”

Bragman points to meta-analysis conducted in 2012 by researchers from Harvard School of Public Health and China Medical University in Shenyang that found “strong indications” that fluoride may adversely affect cognitive development in children. Meta-analysis is a statistical procedure for combining data from multiple studies.

A study by researchers from the University of Otago in New Zealand in 2014, however, cast doubt on those findings. This study examined the IQ scores of 942 New Zealanders first at ages 7 to 13 and then again at age 38 and found no significant differences associated with fluoride exposure.

In December the Marin Coalition hosted a debate on the health effects of fluoridation that pitted Dawna Gallagher-Stroeh, a leading local opponent of fluoridation, against Dr. Howard Pollick, clinical professor in the Department of Preventive and Restorative Dental Sciences at the University of California, San Francisco, School of Dentistry.

At that event, Pollick said every U.S. surgeon general has supported fluoridation and more than 100 national and international organizations — including the American Dental Association, the American Medical Association and the World Health Organization — endorse the practice.

Pollick also said that the United States Public Health Service reviewed all of the evidence in 2015 and found that fluoridation is safe and effective.

At the same meeting, Rita Lanphier, past president of the Marin County Dental Society, said fluoridation is particularly helpful for people who don’t or can’t get to a dentist regularly.

But Gallagher-Stroeh asserted that there are 300 studies that show that fluoride is a neurotoxin capable of lowering intelligence quotient levels.

Regarding the health debate, Gibson said, “I’m quite frankly an agnostic on that. I’m not a scientist. I’m in no position to say one way or the other.”

Gibson said regardless of the health effects he is sympathetic to the argument that people should be allowed to decide for themselves whether or not they want to ingest fluoride.

“I think that is a good argument,” he said, “but I don’t have to wrestle with that because the law tells us to do it.”

Gibson said fluoridation of Marin Municipal Water District’s water is mandated by two local ballot measures and a state law.

MMWD started adding fluoride to its water in 1973 after a measure calling for fluoridation on the November 1972 ballot passed with the support of 57 percent of voters. Marin voters reaffirmed their support for fluoridation by giving 53 percent support to a local ballot measure in 1978.

Then in 1995, Assembly Bill 733 became law, requiring public water systems that have more than 10,000 connections to provide fluoridated water as long as they don’t use ratepayer funds. The North Marin Water District, which provides water to Novato and West Marin, doesn’t fluoridate its water and does not fall under the rules of AB 733.

“I can’t as a board member cast a vote that violates the law,” Gibson said. “I’m not going to do that.”

The email being circulated by fluoridation opponents asserts that the 1995 law “legally allows communities not to fluoridate their water and pay a voluntary penalty instead.”

MMWD spokesman Lon Peterson said, “We’re not aware that it is voluntary.”

Bragman said he plans to meet with the water district’s attorney before Tuesday’s meeting “to go over what our options are.”

Ultimately, Bragman said, another ballot measure might be required to change the policy.

Gallagher-Stroeh led an unsuccessful effort to put an initiative on the November 2016 ballot that would have required MMWD to stop adding fluoride to its water until it could provide residents with more information on the process.

Tuesday’s meeting of the MMWD board begins at 7:30 p.m. at 220 Nellen Ave. in Corte Madera.