The chairman of a Senate committee has asked the Environmental Protection Agency to review its standard for fluoride in drinking water because of renewed concerns over potential adverse health effects.

In a July 25 letter to the agency, Sen. Bob Smith (R.-N.H.), chairman of the Senate Environment and Public Works Committee, wrote that “recent scientific reports show potential adverse effects from fluoride.”

This new evidence, along with a “nationwide concern regarding fluoridation of the public drinking water supply,” warrants a new review of the contaminant, Smith said in the letter to J. Charles Fox, EPA’s assistant administrator for water.

“I urge EPA to conduct an in-depth analysis of fluoride in drinking water based on the best available, peer-reviewed science, as required by the [Safe Drinking Water Act], and also to evaluate whether fluoride additives, including fluosilicates, provide a safe alternative to sodium fluoride added to drinking water,” Smith said.

EPA is not expected to conduct a review of fluoride, a Centers for Disease Control and Prevention official told BNA, but Smith’s request indicates that the long-standing controversy over its use is not a dead issue.

In addition to Smith, Rep. James Sensenbrenner (R.-Wis), chairman of the House Committee on Science, and Rep. Ken Calvert (R.-Calif.), chairman of its Subcommittee on Energy and Environment, also are investigating fluoridated drinking water.

Debate Rages On.

Use of fluoride, a naturally occurring micronutrient, has been controversial almost since it was introduced in public water supplies in the 1940s to help prevent tooth decay. It now is used in water supplied to more than 40 percent (62%) of the U.S. population.

Fluoridation refers to adding chemicals such as sodium fluorosilicate or hydrofluosilicic acid to water where the water is naturally deficient in fluoride.

Despite fluoridation’s endorsement from many scientific organizations, many in the scientific and medical communities–as well as the public–continue to fight its use.

The Safe Drinking Water Act Amendments of 1996 requires EPA to conduct a six-year review of all drinking water standards, and to revise them if necessary. The review of existing standards is required to begin August 2000 and to be completed by August 2002, according to Smith.

Until 1986, EPA had an interim standard ranging from 1.4 parts per million to 2.4 ppm, depending on the temperature of the water. In 1986, the agency set an enforceable ceiling of 4 ppm for fluoride to protect against brittle bone disease. A nonenforceable, secondary standard is set at 2 ppm to protect against dental fluorosis (tooth discoloration).

Host of Ills.

Even these levels are too high, according to opponents of fluoridation, who claim the substance may be linked to a number of adverse health effects, including birth defects, neurotoxicity, hyperactivity/attention deficit disorder, autism, increased bone fractures in young adults, and early onset of puberty in young women.

Proponents of fluoridation, including the American Dental Association, the American Medical Association, CDC, the U.S. Public Health Service, and the U.S. Surgeon General, maintain fluoridation helps prevent tooth decay and possibly osteoporosis.

In recent years, however, some medical and dental professionals have broken ranks with these professional organizations and spoken out against fluoridation. Some dentists now believe fluoride protects against cavities only when applied topically, not through systemic ingestion.

Smith’s request to EPA was prompted by testimony at a June 28 (sic) Senate subcommittee hearing by William Hirzy, a scientist who spoke on behalf of the National Treasury Employees Union Chapter 280.

Moratorium Sought.

Hirzy, an EPA employee who has long dissented from EPA’s official position, called for a national moratorium on fluoridation until more epidemiological evidence is available.

Congress should mandate an independent review of a 1990 National Toxicology Program cancer bioassay that was altered by downgrading the risk, according to Hirzy. The initial results of the study found “clear evidence of carcinogenicity in male rats,” which would have ended fluoridation, he said. This finding was changed in the published version to “equivocal evidence of carcinogenicity in male rats,” according to Hirzy.

Although 90 percent of fluoridation programs use two waste products of the fertilizer industry–hydrofluosilicic acid and sodium silicofluoride–EPA says it is unable to identify any chronic studies using these chemicals, Hirzy said. He asked Congress to mandate that these products be used in any future toxicity studies, rather than a substitute chemical.

In addition, EPA should establish a standard for silicofluorides that is protective of sensitive subpopulations, as required by the SDWA, he said.

Hirzy also cited new research linking fluoride exposure to increased dental fluorosis, adverse effects on the brain, elevated bone cancer in young men, elevated blood-lead levels in children, and anti-social behavior.

Cancer Finding.

The potential benefits and adverse health effects of fluoride have been hotly debated almost since it was introduced in a few U.S. drinking water supplies in 1945.

Because of these concerns, the National Toxicology Program, which is run by the National Institute of Environmental Health Sciences, conducted a study in 1990 that found some male rats exposed to sodium fluoride developed bone cancer.

Prompted by this finding, the Department of Health and Human Services conducted another study in 1991 on benefits and risks, which failed to establish an association between fluoride and cancer.

In 1991, EPA asked the National Research Council to assess fluoride and advise the agency on whether it should revise its standard of 4 ppm. In 1993, the research group determined that a 4 ppm standard is protective of public health.

State or Community Decision.

Each state or local community decides whether or not to fluoridate its water, according to EPA.

As of 1992, about 42 percent (sic, 62%) of U.S. residents who obtain their water from public water supplies were exposed to fluoride in their drinking water, Tom Reeves, a national fluoridation engineer at CDC, told BNA.

Of these people, about 10 million drink water that is naturally fluoridated, and 135 million people water with added fluoride.

Since 1990, dozens of communities have rejected fluoridation, according to Maureen Jones of the antifluoridation group Citizens for Safe Drinking Water, which is based in San Diego.

However, this trend to reject fluoridation has reversed itself in the past three or four years, and more communities now vote for fluoridation than against it, Reeves said. This change was seen when communities switched from “education programs” to “political style campaigns” to “sell” fluoridation, he said.

Public Health Achievement.

CDC called community water fluoridation “one of greatest public health achievements of the 20th century” in an Aug. 8 letter to Calvert.

“[W]ater fluoridation remains the most equitable and cost-effective method of delivering fluoride to all members of most communities, regardless of age, educational attainment, or income level,” CDC Director Jeffrey Koplan wrote.

“The per capita cost of water fluoridation over an entire lifetime can be less than the cost of one dental filling; however, approximately 100 million American children and adults (38 percent of Americans served by public water systems) do not have access to water containing enough fluoride to protect their teeth,” Koplan said.

CDC noted that the prevalence of dental fluorosis is increasing in both nonfluoridated and fluoridated areas. This increase is probably due to the ingestion of fluoride from dental products during the first six to eight years of life, the agency said.

Calvert had asked CDC several questions regarding the use of fluoride and enamel fluorosis in a May 8 letter.

CDC is expected to release recommendations on total fluoride exposure in the spring of 2001, Reeves said.