There are other things Roger Burt should be doing right now. So many other things.

He’s newly retired, so he and his wife, Jeannie, could be traveling the world. Or unpacking the boxes in the front hall of their new Laurelhurst bungalow. Or he could be following through on his plan to volunteer at a local hospital or with hospice.

Instead, he’s writing emails, answering phone calls and doing exactly what he’s been doing for the past 34 years: fighting efforts to fluoridate Portland’s water supply.

“I’m chagrined that it’s still an issue,” Burt said this week. “I’m astounded.”

Burt, a leader of the last campaign against fluoridation and one of the public faces of this new battle, is a quiet, calm, introverted man, not a fire-breathing, anti-government radical. But he knows what you’re thinking. You hear a guy has been fighting something as seemingly basic as fluoridation for this long, and your brain goes someplace kooky.

“That’s the first thing people think, that I’m crazy, because saying no to fluoride in the water goes so against prevailing wisdom,” he said. “It seems like a no-brainer. I understand. I’ve been there.”

In 1972, he was living in Marin County, Calif., when officials there asked the public for permission to fluoridate. Burt read the voter’s pamphlet and was convinced: Supporters included the American Medical Association, every local politician and scores of dentists.

He voted yes, along with a majority of his neighbors.

A year later, Burt moved to Oregon. He became an active environmentalist, supporting Greenpeace and learning all about water quality.

When Portland voters were asked to consider fluoridation in 1978 in the name of stronger teeth, Burt paid more attention. He read the information put out by opponents, then drove up to Oregon Health & Science University to do his own research at the medical school library.

“I have a bachelor’s degree and a master’s degree in psychology and so I know something about research methodology,” he said. “I just wanted to see for myself.”

He found, among other things, a 1975 study that tied high levels of fluoride to weakened kidneys in chimpanzees.

“There were real issues that weren’t being discussed,” he said. “I became a lifelong believer.”

At this point, “lifelong” is no longer hyperbole. Portland voters approved fluoridation in 1978, but Burt helped lead the 1980 ballot fight that overturned that decision. He spent eight years as the lead plaintiff in a lawsuit accusing Multnomah County health officials of improperly using county time and money to campaign for fluoridation. (Burt won.) Also that decade, he persuaded city officials to toughen regulations against lead in city drinking water. And he served two terms on a city water quality commission that recommended against fluoridation when he was a member in 1994.

Burt and other opponents say fluoridation simply doesn’t have enough of a proven benefit to justify the risks. They point to studies that suggest fluoride in large enough doses can reduce children’s IQs, damage kidneys and weaken bones.

Health advocates say Burt and his allies are well-meaning yet misguided. The Centers for Disease Control and Prevention acknowledges that excessive consumption of fluoride over a lifetime can potentially increase the likelihood of broken bones and that some children are exposed to too much fluoride while their teeth and bones are developing. But federal officials say it is “highly unlikely” that the 196 million Americans whose water is fluoridated ingest enough to pose a health risk.

Burt said he has no problem with fluoride — “I use Sensodyne toothpaste; I have good teeth; I even smile sometimes,” he said — but opposes mass, involuntary medication with it.

“Water quality became something of a spiritual issue for me,” he said. “I also don’t have kids, so maybe I have more discretionary time than some people.”

He was 35 when his fluoride fight began. He’s 69 now, just retired from a job as a drug rehabilitation counselor for the state. He and his wife downsized this summer, trading their Buckman home for a smaller place in Laurelhurst.

“I really admire his determination. I admire his wife, too, for tolerating this all over again,” said Kimberly Kaminski, the leader of Oregon Citizens for Safe Drinking Water, the group leading the latest fight against fluoride. “They worked so hard back in the 1980s. Now it’s like all of his work is going down the drain.”

“Back when he started in this, he really was a radical,” said Bill Osmunson, a Lake Oswego dentist and anti-fluoride activist. “We have a real movement now, but it still takes remarkable bravery: I have lost friends and have been shunned by colleagues. It’s an amazing thing that Roger has stuck with it for this long.”

A year ago, anti-fluoride activists heard rumblings that a coalition was lobbying City Hall to reconsider fluoridation yet again.

“We were very naive,” said Burt, a Democrat. “We thought they were just doing an assessment of support. We thought they would certainly wait until after the election, when there’s a new mayor and a new council, to pursue this. We thought they would let the public decide. We didn’t realize the lengths they would go to.”

On paper, his words might look angry. In person, he sounds more impressed than anything else.

“I have to hand it to them, it’s superlative political strategizing,” he said. “They caught us flat-footed.”

And so those retirement plans, the volunteering, the getting out more, are on hold. Burt estimates he’s spending 20 to 30 hours a week meeting with other anti-fluoride folks, sending emails, preparing research. He’s the only person involved in the 1980 campaign back for another round.

“I don’t really want to do this. The last campaign was not pleasant. There was infighting. We got some very nasty phone calls at home. People threw out all kinds of insults,” he said. “But when you believe in something the way I believe in this, you can’t stay quiet.”

In other words: When you care about something as much as he cares about this, you don’t mind if people call you crazy.