The Oregon House on Monday passed a bill requiring cities with more than 10,000 people to add fluoride to their drinking water, but it allows them a way out if they don't have the money. The bill passed by a 36-22 vote.

About 20 percent of Oregonians drink fluoridated water. Salem is one of the cities where fluoridation is required by local ordinances. Keizer also adds fluoride to its water.

The bill passed by the House would apply to Portland, Medford, Bend and other cities that do not fluoridate their water and have resisted efforts in the past to require it.

Under an amendment to the legislation, however, if cities don't have the money to pay for adding fluoride to their water supplies, they wouldn't have to raise rates or taxes to do so -- which essentially would make those cities exempt from the law.

The amendment was added when it became clear that no state funds would be available to help cities with the cost.

Lawmakers for decades have argued about requiring statewide fluoridation. Every surgeon general since the 1950s has endorsed it.

Dentists say that adding fluoride to water is a cost-effective way to cut back on tooth decay.

Rep. Billy Dalto, R-Salem, said that costs to fluoridate water can range from less than $1 to more than $5 per person per year, far less than the cost of treating preventable cavities.

"The more than 400,000 children with tooth decay in Oregon cannot afford the status quo," Dalto said.

Critics argue that there are health risks from exposure to the chemical, which is considered a toxic substance in high enough quantities.