The Salt Lake Valley Health Department’s announcement Tuesday that it isn’t close to developing a water fluoridation plan should concern voters, because health professionals and elected officials were united last year in their assurance that the process would be cheap and easy.

“The major water companies in Salt Lake and Davis counties have done careful cost projections,” promised Anthony C. Tidwell and Joseph Newton, prominent fluoridation advocates, in a letter to the editor. “There will be a very modest cost,” agreed David R. Irvine of Utahns for Better Dental Health in another letter.

Kathryn Vedder, director of the Salt Lake Valley Health Department, sounded confident in October that the costs would be 90 cents per person per year, which strongly implied that officials had a firm handle on the logistics involved in fluoridating Salt Lake County’s myriad sources of water.

They didn’t, and it’s a measure of the depth of last year’s ignorance that they still don’t five months later. “It’s more complicated than we thought and than people were able to articulate,” Vedder said Tuesday. “We need more information.”

That very point was raised by fluoridation opponents last fall when the department was dragged screaming and kicking into a public debate on the issue. Some even had the bad manners to suggest that exact costs on fluoridation be made public before voters decided whether to do it.

But such opinions were received by the fluoridation juggernaut much as affronts to the faith were received by the Spanish inquisitors. The juggernaut had spoken, and “more information” was the last thing it wanted until victory was secured.

To be fair, some of the anti-fluoridation claims did seem far out, but in regard to the cost and complexity of the process, opponents received a strong second Tuesday from someone who should know: “This is expensive and labor-intensive,” said Phil Markham, Murray City Public Works manager.

The Health Department might yet make its costs mesh with last year’s fuzzy estimates. Water districts could save money by bypassing some of the county’s 200 wells, though that would deprive an undetermined number of people of their full fluoride dose during the summer months.

But even if they can make the numbers jibe, health officials aren’t off the hook. They said last year that they knew, and it is now clear that they did not. They violated the public trust, and the public should not forget it.