PASCO — Four out of five dentists might have their opinion, but it was five out of seven council members who accepted a grant for water fluoridation on Monday.

The city has put fluoride in its water supply for seven years to bolster the oral health of its public. But the practice was reconsidered recently because the city plans to start construction on a second municipal water treatment plant this summer.

“The state department of health … requires that the entire water supply be provided the same treatment,” City Manager Gary Crutchfield said.

As long as one water treatment plant puts fluoride in the water, the second one has to, too.

“So it’s all in or all out,” he said.

The council voted to accept a $100,000 grant from the Washington Dental Service Association to go toward the cost of installing fluoridation equipment at the new plant. Councilmen Tom Larsen and Bob Hoffmann voted against the grant.

The vote came after a lengthy discussion about the merits of fluoridating the public water supply.

Pasco residents Bernice Woodbury, Karen Miller and Fred Nimmo spoke against the practice, saying fluoride harms people’s health and water pipes.

“I have done some research on what this acid is,” Miller said. “… It is an inorganic corrosive acid, a volatile, colorless hyposcopic corrosive liquid compound formed by decomposing metallic fluoride. … It can kill you with a heart attack just by breathing it.”

“I see this as giving poison water to our children,” Nimmo said. “… I believe it is an abuse of our children and all the citizens of Pasco.”

Mayor Joyce Olson said the critics of water fluoridation were a vocal minority spreading misinformation. In years past, she was contacted by fewer than 10 people against it.

Since the council discussed the fluoridation grant last week, she has received a dozen e-mails against it, mostly from people from places outside the area, such as Florida and Pennsylvania, she said.

“Frankly, I’m tired of hearing people say that we’re poisoning people,” Olson said. “We’re adjusting it to a level that actually makes it beneficial to them. … The day we find out otherwise, I will be the first one to say let’s stop doing this.”

Councilwoman Rebecca Francik recommended the city be sure to include fluoridation sampling in its testing of the municipal water system, to make sure inordinate amounts aren’t making it to people’s faucets.

But she said that as a librarian, she has access to a wide range of information on fluoridation that has assured her it’s beneficial to people, not detrimental.

“There are people who are raising questions, but there’s no science backing up the questions. They’re finding anomalies,” Francik said.

Councilman Al Yenney voted to accept the grant because it saves the city money but doesn’t prevent the city from discontinuing fluoridation later.

He said he personally is leaning toward discontinuation and has suggested calling for a public referendum on fluoridation in 2010.