Seattle water department begins fluoridation of water supply on January 12, 1970.

  • By Heather Trescases and Kit Oldham
  • Posted 12/07/2002
  • Essay 4040

On January 12, 1970, the Seattle water department begins fluoridating the water that supplies the city and many surrounding communities. The controversial move comes more than a year after city voters approved fluoridation, at a level of one part per million (1.0 ppm), in the November 1968 election, after having defeated fluoridation proposals in 1952 and in 1963. Supporters, including local, state, and national health agencies, argue that adding fluoride to the water supply will harden teeth and reduce tooth decay in children. Opponents, who also number doctors and scientists within their ranks, question studies showing fluoridation's benefits, argue that the chemical has harmful side effects, and strongly object to what they call compulsory mass medication of the population. Debate over the issue will continue, as will fluoridation of Seattle's water supply (at a reduced level of 0.8 ppm after 2011).

Controversial from the Start

Fluoridation of public water supplies has been hailed as one of America's "great public health achievements of the 20th century" ("Community Water Fluoridation"). The federal Centers for Disease Control, the American Dental Association (ADA), and many others credit adding fluoride to drinking water with significantly reducing tooth decay. But from the time fluoridation was introduced in the 1940s it has been vigorously opposed by scientists and activists who argue that it means forcing the public to consume a toxic industrial waste product whose benefits are unsubstantiated and which can cause serious health hazards.

Fluoride's harmful effects on teeth were noticed before its benefits. Fluoride occurs naturally in soil and water, generally in very small quantities. (For example, analysis of Seattle's water supply from the Cedar and Tolt rivers in 1967 and 1968, before fluoridation began, showed low natural levels of fluoride ranging between 0.07 and 0.3 ppm.) In the early twentieth century, dentists in areas where drinking water had high natural levels of fluoride saw many patients with significant teeth staining and some pitted enamel. Investigation determined that fluoride caused the problem, which was named fluorosis. After dentists noticed that patients with fluorosis had less tooth decay than others, and studies in the 1940s reported fewer cavities in children where water had higher natural levels of fluoride, some dentists suggested adding fluoride to water supplies to reduce tooth decay.

This proposal may have seemed surprising given that fluoride was known to be toxic in large quantities. However, proponents argued that a fluoride concentration of 1 to 1.2 ppm effectively reduced decay while causing only low levels of mild fluorosis and, they asserted, no other problems. Fluoridation was first tested in 1945, when Grand Rapids, Michigan, followed by three other North American cities, began adding fluoride to their water supply. Longterm studies compared each with a city that did not fluoridate. Preliminary results announced such dramatic reductions in decay that proponents did not wait for the studies to conclude. By the early 1950s, the U.S. Public Health Service was actively promoting fluoridation, as were the ADA, state and local health authorities, and others. From the 1950s through the 1970s fluoridation spread rapidly, but not without bitter political controversy.

Across the country activists warned that fluoridation's health risks had not been adequately studied and objected to having the chemical forced on them. While opposition to other controversial technologies, such as nuclear power or genetic engineering, is often seen as leftwing, fluoridation opponents, especially at first, tended to be identified with the political right, with some calling fluoridation a communist plot. Other opponents blamed the fertilizer industry, which supplied most chemicals used in fluoridation, for adding what they characterized as toxic waste products to drinking water. Health officials responded that additives like fluorosilicic acid (also sometimes referred to as hydrofluosilicic acid) were subject to strict quality and purity standards.

Third Try Succeeds

The early push for fluoridation reached Seattle in 1951, when the Seattle-King County Department of Public Health asked the city council to treat city drinking water with fluoride to combat tooth decay in children. The proposal faced fierce opposition and the council sent the fluoridation question to voters, who overwhelmingly rejected it in March 1952. A second fluoridation measure, in March 1963, was also rejected, although by a smaller margin.

Fluoridation surfaced once again on the city council's agenda in 1968. Proponents of fluoridation included the State Health Department, dental associations, and a group of women called Mothers for Fluoridation. On April 8, 1968, the mothers group presented Council President Floyd C. Miller (1902-1985) with a petition bearing approximately 3,500 signatures requesting that the city's water be "adjusted to contain one part fluoride for every million parts of water" ("Mothers' Group Petitions ...").

In presenting the petition, Patricia Schultz said that, based on State Health Department statistics, parents would save between $700,000 and $1 million per year in dentist bills as a result of fluoridation. Dr. Olin Hoffman, head of the State Health Department's Dental-Health Section, described fluoridation as "one of the greatest public-health measures of all time" ("Fluoridation Battle Looms ..."). One of the key arguments put forth by those in favor of fluoridation was that underprivileged and low-income families could not afford proper dental care for their children, so voluntary fluoridation, such as drops, tablets, or vitamin-additives, was out of the question. Fluoridation of the city's water would therefore be of great benefit to the poor.

Local opponents of fluoridation, such as the Pure Water Association, headed by Seattle physician Dr. Eugene McElmeel, which had led the opposition to the 1963 fluoridation measure, were equally active. They dismissed Health Department estimates of benefits as inaccurate and warned of health hazards, such as mottled teeth, illness, or even death from fluoride consumption. Opponents also raised the prospect of mass medication, asserting that fluoridation would force a medical treatment upon those did not want it for religious or other reasons. Dr. McElmeel presented the council with a letter from the president of the state chapter of the American Civil Liberties Union (ACLU) suggesting that water fluoridation, like compulsory vaccination, would violate citizens' rights.

A public hearing on the fluoridation issue took place on June 28, 1968, after which the city council voted 5 to 4 to fluoridate Seattle's water. Existing laws granted state and local officials the power to compel fluoridation without first seeking a public referendum. However, according to the city charter, opponents had 30 days following the council's vote to gather sufficient signatures (approximately 14,000) to put the question to a public referendum. Ultimately, on July 22, 1968, the city council decided, with two members switching position, to let water-users, at least those who resided within the city, decide the fluoridation issue, by referring the matter to city voters. (Although the Seattle water department supplied, and would fluoridate, the water used in many surrounding jurisdictions, only Seattle residents voted on the measure.)

On November 5, 1968, Seattle voters approved water fluoridation proposal by a margin of 57 to 43 percent. Fluoridation measures were also on the ballot in Bellingham, Spokane (an advisory vote), Steilacoom, and Yakima, but those measures all failed. After the vote, Seattle water superintendent Kenneth Lowthian estimated that it would take "six months or so" for fluoridation to begin ("Seattle Voters Approve ...").

A Dramatic Beginning

In fact, due to difficulties in obtaining the chemicals and needed equipment, it was more than a year before the water department was ready to being adding fluoride to the water supply. By early 1970, large fiberglass tanks holding thousands of gallons of hydrofluosilicic acid had been installed at Seattle Water Department treatment facilities at Landsburg on the Cedar River and east of Duvall on the Tolt River, where the chemical would be metered into the water at a rate of one part fluoride per million parts water. Dr. Sanford Lehman, Director of the Seattle-King County Health Department, explained that fluoride was to be added to the water supply "in order to reduce the incidence of dental caries (tooth decay) among young people in a long-range preventative program" ("Date for Fluoridation Set").

The initial introduction of fluoride to the water supply on January 12, 1970, was a dramatic occasion. The Lake Youngs storage reservoir on the Cedar River supply was located downstream from the treatment plant at Landsburg, but it was not practical to empty its 11 billion gallons of treated but unfluoridated water and refill it with fluoridated water from the treatment plant. Instead, the reservoir was taken out of service for several days while large tanker trucks full of concentrated hydrofluosilicic acid dumped some 45,000 gallons of the chemical into the reservoir to bring the fluoride level up to 1 ppm.

Almost immediately after the first hydrofluosilicic acid was pumped into the lake, the water department began receiving complaints that fluoride was hurting people's mouths and killing their goldfish and plants. To these first complaints, the department had an easy response: no fluoridated water had yet even reached the city. However, while water department officials joined their counterparts in the local and state health departments in strongly favoring fluoridation as "an effective measure for reducing dental caries" (Lowthian to Royer, March 31, 1983, p. 11), it turned out that fluoridation posed some practical problems for the department.

For one thing, fluoridation, along with other factors, contributed to an increase in internal corrosion problems in the 1970s, sparking more than a decade of work to identify the causes and develop treatment to reduce the problem. Tolt River water is naturally somewhat more corrosive than Cedar River water and in the mid-1960s, when Tolt water was introduced to the system, there was a spike in complaints about corrosion of internal plumbing and water quality problems caused by dissolved metals from the plumbing. Then in 1970, in addition to starting fluoridation, the use of ammonia in combination with chlorine was discontinued, so that chlorination left free chlorine throughout the distribution system, improving disinfection but also making the water more corrosive. An engineering firm hired by the department documented these causes of corrosion in a three-part Internal Corrosion Study, released in 1976 and 1978, that proposed solutions that the department implemented in the early 1980s by building corrosion treatment plants on both supply systems, which largely eliminated corrosion complaints.

The industrial source of fluoride additives occasionally caused practical difficulties. In 1982 and again in 1986 shortages forced the Seattle water department to temporarily suspend fluoridation. Superintendent Lowthian's 1982 "detailed annual report" explained that because "[t]he fluoridating chemical used by Seattle -- fluosilicic acid -- is a byproduct of the phosphate fertilizer industry, which has suffered recent setbacks due to reduced domestic usage and increased foreign competition," very little had been produced for several months and the department could not obtain a supply (Lowthian to Royer, March 31, 1983, pp. 1, 12).

Fluoridation and Debate Continue 

Aside from the temporary interruptions caused by shortages, fluoridation continued under the water department and then Seattle Public Utilities, which took over operation of the water system in 1997. As of 2014 fluoridation, along with chlorination, ozonation, corrosion control, screening, and filtration (of Tolt water) or ultraviolet light treatment (of Cedar water), was accomplished at sophisticated treatment facilities completed in 2000 on the Tolt supply and in 2004 on the Cedar. 

Controversy over the practice also continued, locally and nationally. Both sides of the debate pointed to voluminous scientific studies that supported their position. Proponents asserted that fluoridation had led to substantial reductions in tooth decay and that no adverse health effects were proved at the levels used. Opponents responded that similar declines in decay rates also occurred in U.S. communities and others around the world where water was not fluoridated (relatively few countries besides the U.S. fluoridate water supplies), and insisted that even low levels of fluoride were linked to various health problems.

After the 1970s, the rate of fluoridation across the country slowed, due in part to continuing opposition, but also because with most large systems already fluoridated, the per capita cost of fluoridating remaining smaller systems was higher. In Portland, Oregon, one of the largest U.S. cities not fluoridating its water (a 1978 approval was reversed before fluoridation began), opponents who objected to adding the chemical to a supply known for its pristine water collected enough signatures to force a popular vote on a city council-approved plan to adopt fluoridation in 2014, and then defeated the plan by a large margin in a highly contentious May 2013 election. Eight years earlier, anti-fluoridation forces had prevailed by a narrow margin in a vote in Bellingham.

New Recommendations

Public health authorities continued to strongly recommend that drinking water be fluoridated, but in the first decades of the twenty-first century federal agencies also began considering reductions in fluoride levels. In 2006, a National Academy of Sciences report urged the Environmental Protection Agency (EPA), which sets "maximum contaminant levels" for substances in drinking water, to reduce the maximum allowed fluoride level from 4 ppm to 2 ppm, based on findings that prolonged intake at 4 ppm increases the risk of brittle bones, fractures, and bone abnormalities, and that even the 2 ppm level can cause severe fluorosis. Although a maximum limit of 2 ppm, aimed at high natural levels of fluoride in some water, would not impact fluoridation, which is conducted at lower levels, some EPA scientists and other employees, speaking through their unions, joined fluoridation opponents in asking the EPA to reduce allowed fluoride levels to zero, based on research indicating that it can cause cancer.

In a joint announcement with the Department of Health and Human Services (HHS) in January 2011, the EPA said that it would review whether to reduce the maximum fluoride limit, while HHS presented a proposed recommendation reducing the level of fluoride added through fluoridation from the existing recommended range of 0.7 to 1.2 ppm to just 0.7 ppm (0.7 milligrams of fluoride per liter of water). The joint announcement reiterated "the health benefits of water fluoridation, an important tool in the prevention of tooth decay" while noting that the new actions would help in "avoiding the unwanted health effects from too much fluoride" (News Release).

One reason for the proposed reduction to 0.7 ppm was the possibility (long raised by fluoride foes) that some Americans, particularly children, might actually be ingesting too much fluoride, as a result of the chemical being added to toothpaste, many bottled drinks, and other products in addition to tap water. Based on the draft recommendation (which as of early 2014 has not been finalized), Seattle Public Utilities, which also reiterated support for fluoridation, reduced fluoride levels in Seattle's water from 1 ppm to 0.8 ppm (the lowest level allowed by existing state standards for systems that fluoridate).


Files 216078, 247766, and 262435, Folders 8, 9, and 10, Box 1, Series 1802-B4, Seattle Municipal Archives, Seattle, Washington; "Council Reversal Leaves Fluoridation Up to Voters," Seattle Post-Intelligencer, July 23, 1968, p. 1; "Fluoridation Defeated by Heavy Margin," The Seattle Times, March 12, 1952, p. 8; "Voluntary Fluoride Use Urged by Group," Ibid., March 13, 1963, p. 9; "Mothers' Group Petitions for Fluoridation of City Water," Ibid., April 8, 1968, p. 3; Herb Robinson, "Fluoridation Battle Looms Once Again," Ibid., May 14, 1968, p. A; Douglas Willix, "City Council Approves Fluoridation," Ibid., June 28, 1968, p. 1; "City Council Hears Fluoridation Pleas," Ibid., June 28, 1968, p. 31; "Seattle Voters Approve Fluoridation of Water," Ibid., November 6, 1968, p. 8; "Fluoridation Defeated at Yakima, Spokane," Ibid.; "Date for Fluoridation Set," Ibid., December 13, 1969, p. 33; Al Dieffenbach, "Fluoride Will Begin Flowing in Limited Amounts This Week," Ibid., January 11, 1970, p. A-1; Mike Stobbe, "US Says Too Much Fluoride Causing Splotchy Teeth," The Seattle Times, January 7, 2011 (; Steven Dubois, " Portland, Ore., Rejecting Water Fluoridation," Ibid., May 21, 2013; Annual Report Supplement for the Year 1967 (Seattle: City of Seattle Water Department, 1968), Ex. 23; Annual Report Supplement for the Year 1968 (Seattle: City of Seattle Water Department, 1969), Ex. 24; Kenneth Lowthian, Superintendent of Water, to Mayor Charles Royer and Seattle City Council, March 31, 1983 (letter containing "a detailed annual report ... for calendar year 1982"), and Lowthian to Royer and Council, March 31, 1987 ("detailed annual report ... for calendar year 1986"), bound with water department annual reports, Seattle Room, Seattle Public Library, Seattle, Washington; Internal Corrosion Study: Phase 1 Report (Seattle: Kennedy Engineers, Inc., and City of Seattle, 1976); Internal Corrosion Study: Phase 2 Report and Phase 3 Report (Seattle: Kennedy Engineers, Inc., and City of Seattle, 1978); "News Release: HHS and EPA Announce New Scientific Assessments and Actions on Fluoride," U.S. Department of Health & Human Services website accessed January 7, 2014 (; "Community Water Fluoridation," Centers for Disease Control and Prevention website accessed January 7, 2014 (; Edward Groth III, "The Debate Over Food Biotechnology in the United States: Is a Societal Consensus Achievable?" Consumers Union website accessed May 4, 2012 (; "Fluoride," Seattle Public Utitlities website accessed January 3, 2014 (; Online Encyclopedia of Washington State History, "Seattle Water System -- A Slideshow" (by Kit Oldham), (accessed January 6, 2014).
Note: This essay was revised (including changing its date from the date of the vote to that of fluoridation beginning), expanded, and updated on January 10, 2014.

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