Questions about drinking water fluoridation run deep, through 50-plus years of controversy about a mainstream norm for many American taps, including 4,200 served by Crescent City’s Municipal Water Works.

Now a measure to stop fluoridation is on the city-wide ballot for the second time in two years.

In 2010, 555 out of 973 city voters who cast ballots decided to keep adding a fluoride compound to the municipally-owned supply, which serves an estimated 14,000 area residents. The majority of them live outside city limits and are ineligible to vote on Measure A in the upcoming Nov. 6 general election.

Rather than asking Crescent City voters to decide if fluoridation fuels internal maladies in the name of oral health, this version of Measure A asks residents to nix the mix until a global chemical supplier vouches for its safety “for all water consumers.”

“The reason this will never happen is obvious. The safety of any substance, even water itself, depends on dosage,” write those arguing against Measure A on the Nov. 6 city-wide sample ballot, including: Dr. John Tynes, Irene Tynes, Mayor Kathryn Murray and Martha Scott.

Basic Chemical Solutions’ manager in Redwood City had no comment this week. The company periodically supplies Crescent City with about 4,000 gallons of 23-percent concentrate hydrofluosilicic acid, the most commercially pervasive compound of fluoride used in drinking water for an estimated 80 million Americans, according to the U.S. Centers for Disease Control. The compound is created when phosphate rock is ground up and treated with sulfuric acid during the manufacture of fertilizer.

Proponents of Measure A argue that “since the manufacturers of hydrofluosilicic acid will not submit the toxicological data or the list of contaminants in their product, it is technically illegal to put this substance in the water,” in the sample ballot’s argument in favor of Measure A signed by Katherine Kelly, City Planning Commissioner and Council candidate Joseph Aliotti, Councilwoman Donna Westfall, Jody Mangum, and Kai Vang.

It’s illegal not to fluoridate the water in much of California.

In 1995, the state Legislature began requiring water systems with 10,000 or more connections to fluoridate, without providing any funding for the mandate. The City of Crescent City spends $28,000 on a 15- to 18-month supply of hydrofluosilicic acid.

The city water supply is collected from intake lines driven into the gravel bed of the Smith River. The water is pumped southward to a treatment facility off Kings Valley Road, where chlorine and the fluoride compound are added in keeping with state and federal standards.

Last year the U.S. Department of Health and Human Services, the U.S. Environmental Protection Agency and the American Pediatrics Society recommended that drinking water systems reduce the level of added fluoride to the lowest end of the dosing scale, from 0.7 to 1.2 milligrams per liter of water, denoted ppm.

The Crescent City Council then changed the municipal fluoridation policy accordingly, reducing the range from 1.0 to .7 ppm, though the practical range is subject to minute variations.

“The effectiveness of fluoridation depends on how consistently the water treatment operator maintains the optimal fluoride concentration … He holds the key to better dental health,” says a 1986 U.S. Dept. of Health and Human Services guide to fluoridation for engineers and technicians, one of the references cited on a government website that Crescent City’s annual water quality report lists as a source for information on fluoride, available online at:

http://www.cdph.ca.gov/certlic/drinkingwater/Pages/Fluoridation.aspx.

Proponents of Measure A have directed people to the website www.fluoridealert.org.

Last year the city replaced a check valve that helps keep fluoride in a pump between the water supply and storage tank, after the dose peaked between .8 and .9 ppm.

“You’re talking about one-tenth of one part per million,” City Utilities Director Eric Wier said in a May 2011 Triplicate interview.

The practice of adding fluoride to municipal water systems began in the 1940s after researchers discovered residents had fewer cavities in communities with naturally fluoridated water, though fluorosis (discoloration of the teeth) was more common.

The strengthening effect on bones and teeth is the intent of the additive. Measure A’s proponents take issue with its ingestion, writing “infants, diabetics, people with kidney and thyroid disease, should not consume fluoride.”

“The effect of drinking fluoridated water is non-cumulative. A minute part is deposited in the bones and teeth; the remainder is rapidly excreted through the kidneys,” explains the state public health department’s guide to fluoridation.

The argument against Measure A states that “over 100 health and scientific organizations — from the American Cancer Society to the American Academy of Pediatrics — endorse the benefits of drinking-water fluoridation. The Centers for Disease Control proclaimed fluoridation as one of the 10 greatest public health achievements of the 20th century.”

Recently, fluoridation opponents released documents requested from the CDC, which they say show the 40-year-old endorsement of water fluoridation was informed by dental health professionals and did not include “toxicologists, minority health professionals, experts in diabetes, or specialists outside the agency’s Oral Health Division,” according to a CBS News report from June 2011.

Crescent City started fluoridating its water in 1968.

Back then some decried the notion of being forced to ingest fluoride, but in 1970, a city-wide vote of 441-178 favored continuing the practice.

Proponents of today’s Measure A and those refuting it  both call on city voters to consider the children.

“Our children are suffering high obesity rates, low test scores, yet our supplier, Basic Chemical Solutions will not provide a single toxicological report or contaminants list … Vote yes to protect our children!” wrote the proponents of Measure A in the ballot.

Those arguing against the measure wrote: “Del Norte County does not have even one full-time pediatric dentist. Without fluoridation we simply would not have the dental work force or the money to deal with the explosion of tooth decay that would result. Don’t do this to the children. Vote no.”

Eligible voters have until Oct. 22 to register, in order to participate in the Nov. 6 election.