The editorial in the Watsonville Register-Pajaronian offered local voters some blunt advice: “Shield your eyes,” it said, “because the City Council is preparing to spit in your face.”

That was this month, as the council inched toward finally fluoridating the city’s water -- a state-mandated action that has been bitterly debated since city residents narrowly voted to block it in 2002. At a council meeting in January, an anti-fluoridation activist held up a sign alluding to Nazis. When speakers threatened to boycott local businesses if fluoridation goes through, a council member told them to jump off the parking-garage roof.

Although the argument in the Santa Cruz County agricultural town of 50,000 has raged for years, people on both sides see a resolution as urgent.

Health officials say that Watsonville, with a large population of migrant workers, is in the throes of a dental-decay epidemic. One study of local students found an average of two dental abscesses in every classroom, not to mention an outsize number of cavities.

Still, one of the biggest employers in town -- the Martinelli beverage company, famous for its sparkling apple cider -- said it would rather move a planned expansion elsewhere than use fluoridated water in a new line of juices.

“We believe fluoride is bad for your body so, morally and ethically, we simply cannot put that water in our products,” said John Martinelli, president of S. Martinelli & Co., his family’s business for 142 years. “If half the people in this town don’t want to be mass-medicated, then we shouldn’t be.”

Although water supplies across the U.S. have been fluoridated for decades and the Centers for Disease Control and Prevention has called the process “one of the 10 great public health achievements of the 20th Century,” California has been late to embrace it. Opponents link it to bone cancer, thyroid problems, kidney malfunction, fetal damage and a host of other conditions. Their critics, including most mainstream medical and dental organizations, accuse them of distorting scientific studies.

Suspicion of fluoridation comes from the right and the left. Some see it as a dangerous erosion of liberty. Others believe it’s an underhanded way for businesses to get rid of industrial waste.

In Watsonville, the issue is also economic.

Fields surrounding Watsonville are planted with strawberries, raspberries and a variety of vegetables. But unemployment in the city is estimated at 25%, in part because of the slow agricultural season.

Martinelli’s nonalcoholic sparkling cider was concocted during Prohibition and has been a reliable stand-in for champagne ever since. The company’s cider and apple juice use no water except that in the fruit the company buys by the ton from area orchards.

But this summer, the company plans to roll out juices -- acai, pomegranate, blueberry and others -- made from concentrate and water. And if that water is fluoridated, Martinelli said, customers will balk.

“What we’re talking about is our growth opportunity,” said Martinelli, who says the expansion could add dozens of workers to his 200-person staff. “Watsonville won’t benefit from the growth of our business if I have to take it somewhere else.”

Despite facing a $5 million deficit, city officials said they might help Martinelli pay for the high-tech equipment required to remove fluoride from water.

“We want to make sure he feels welcome to stay in Watsonville,” said Councilman Manuel Bersamin, a fluoridation supporter. “He heads a company that placed Watsonville on the map.”

Meanwhile, say local healthcare professionals, the problem is only getting worse. Michelle Simon, a pediatrician whose joint practice treats 6,000 Watsonville children, said she “has never seen such bad teeth outside Nicaragua.” Dentists swap stories of families who are unable to afford toothpaste and brush only with water.

Salud Para La Gente, a Watsonville clinic, has retrofitted old trailers to offer dental care at local schools.

“It’s an epidemic,” said Dr. Hugo Ferlito, the clinic’s associate dental director. “We’re there in the trenches, and we’re asking government to stand with us and help us out.”

In 2002, residents upset with a city decision to fluoridate thwarted it with an initiative that passed by 2%. Subsequently, courts ruled that the initiative violated a 1995 state requirement that larger jurisdictions add fluoride to their water if outside money is available.

In Watsonville’s case, the CDA Foundation, an arm of the California Dental Assn., is willing to donate more than $1.5 million. Jon Roth, the foundation’s executive director, said a statewide task force looking at Watsonville found “a significant amount of dental disease and a lack of infrastructure to care for underserved residents.”

Whether the foundation’s money will be enough is unclear, as are questions of who would be liable if the city were sued over claims that its water poisoned consumers.

At its contentious meeting last month, a divided council formed a committee to negotiate with the foundation -- a move that some council members saw as a betrayal of democracy.

“The voters have been ignored,” said Greg Caput, a painting contractor completing his first council term and running for Santa Cruz County supervisor.

“We should fight all the way to the end. People will have to drink fluoridated water, wash with it, cook with it, water their plants with it and wash their clothes in it. It’s literally being forced down their throat.”

steve.chawkins

@latimes.com