The 1930s were an exciting time for water infrastructure in North America. A new type of water pipe had been introduced in Canada and the United States just a year earlier. Asbestos cement (AC) water pipe was billed as cheaper, lightweight, and seemingly impervious to deterioration. Over the next few decades, the use of the new material exploded around the world. In a 1951 promotional book, Italian asbestos cement pipe manufacturer Eternit/Italit boasted that by 1948, the pipes it sold “equaled two and a half times the circumference of the world.”
It has been estimated that up to 18 percent of the water distribution pipes in the United States and Canada are asbestos cement. The pipes can contain up to 20 percent asbestos. The old pipes are still in use in dozens of Canadian municipalities.
The use of asbestos cement pipe was largely discontinued in North America in the late 1970s, due to health concerns associated with the manufacturing process of the pipes, and the possible release of asbestos fibres from deteriorated pipes. Contrary to the sales hype decades earlier, it has been determined that the pipes do deteriorate, and their breakage frequency increases with age.
The United States Environmental Protection Agency (EPA) says asbestos fibres may be released from the use of asbestos cement pipes in water supply systems. The agency regulates asbestos in water. It maintains ingested (swallowed) asbestos can “cause lung disease; cancer.” Health Canada says there is insufficient evidence that ingested asbestos is hazardous.
Research and Results in the U.S.A.
In 1974, the U.S. Congress passed the Safe Drinking Water Act. The enforceable regulation for asbestos became effective in 1992, with the maximum contaminant level (MCL) set at seven million fibres per litre (MFL). Material readily available in the EPA archive states that beyond that level steps, “such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.” The EPA maintains the threshold of seven MFL was established to “protect against cancer.” Another page on the EPA website cautions: “Some people who drink water containing asbestos well in excess of the maximum contaminant level (MCL) for many years, may have an increased risk of developing benign intestinal polyps.”
The United States did not jump into regulation lightly. It took decades of very detailed studies before the step was taken. In a 1979 report Exposure to Asbestos from Drinking Water in the United States, the EPA looked at asbestos concentrations in 365 cities in 43 States. “Of the 365 cities, 165 or 45.3 percent were reported to have significant concentrations of asbestos in the drinking water.”
In 1980, the EPA conducted a detailed study entitled Ambient Water Quality Criteria for Asbestos. In part it reads: “Asbestos is a known carcinogen when inhaled. The demonstrated ability of asbestos to induce malignant tumors in different animal tissues, the passage of ingested fibers through the human gastrointestinal mucosa, and the extensive human epidemiological evidence for excess peritoneal, gastrointestinal, and other extrapulmonary cancer as a result of asbestos exposure suggests that asbestos is likely to be a human carcinogen when ingested.”
The dangers of inhaled asbestos had long been known. Concern over ingestion of the mineral was beginning to solidify.
In 1987, the United States Department of Health and Human Services released a study entitled Report on Cancer risks Associated with the Ingestion of Asbestos. The report concluded: “Sufficient direct evidence is not available for a credible quantitative cancer risk assessment of asbestos ingestion at this time.” However, a few paragraphs later this statement can be found: “Nonetheless, this should not be taken to mean that the potential hazard associated with ingested asbestos is an unimportant issue which does not warrant further research. Even if the increased rate of cancer is less than 10 percent of the background rate and cannot be demonstrated by available research tools, the ingestion of water, food, or drugs laden with asbestos by millions of people over their lifetimes could result in a substantial number of cancers.” The report goes on to say that several members of the working group felt it was “prudent public health policy to recommend eliminating possible sources of ingestion exposure to asbestos whenever and to whatever extent possible.” A few sentences later the report highlights “eliminating asbestos cement pipe in water supply systems.”
Canadian Research and Determinations
Canada had been busy too. One of the first studies conducted outside the U.S. was by Health and Welfare Canada. Posted on the current Health Canada website under Guidelines for Canadian Drinking Water Quality: Guideline Technical Document – Asbestos, it reads: “Chrysotile was the predominant type of asbestos identified in a survey of drinking water supplies conducted at 71 locations across Canada in 1977.” The webpage goes on to state: “Based on the results of this survey, which encompassed the water supplies of about 55 percent of the Canadian population, it was estimated that five percent of the population receives water with chrysotile concentrations higher than 10 million fibres/L and that 0.6 percent receives water containing more than 100 million fibres/L.”
The National Research Council Canada (NRC) − a branch of the federal government − has conducted numerous studies into asbestos cement water pipes. All the NRC studies refer to asbestos fibres in water as a “health concern.” One NRC report goes even further; “Severely deteriorated AC pipes also released asbestos fibre into the drinking water, and could pose a hazard of tumors of the gastrointestinal tract, and other organs in consumers.” The 2010 study goes on to say “These AC pipes were laid down before the potential environmental, social, and health impacts were recognized and evaluated. In recent years, problems with AC have gradually become significant including increases in the number of pipe breaks and failures.” Yet another NRC report from 2010 points to the potential danger of using showers and humidifiers in homes where asbestos may be in the water.
Despite this, Health Canada maintains there are no health concerns associated with ingested asbestos. “There is no consistent, convincing evidence that ingested asbestos is hazardous. There is, therefore, no need to establish a maximum acceptable concentration (MAC) for asbestos in drinking water,” reads the Guidelines for Canadian Drinking Water Quality: Guideline Technical Document. In a recent email exchange, a spokesman for Health Canada said although the Health Canada guidelines were published in 1989, a recent review found that “there is little evidence suggesting a casual relationship between asbestos ingestion and cancer.”
Dr. Arthur Frank, a medical doctor and expert in environmental and occupational health at Drexel University in Philadelphia, Pennsylvania, says not regulating asbestos in water is a mistake. “Regulating asbestos in water means that the lives of some Canadians would be saved by not ingesting asbestos in the water they drink, and use in showers,” said Frank, who has spent close to 50-years studying the issue. “There is no question that the ingestion of asbestos, like breathing it, much of which when cleared from the lungs is then ingested, can lead to the development of a variety of cancers, including stomach, small and large intestine, and kidney cancer.”
Canada and America may agree on many things. The danger of ingested asbestos is not one of them.
Julian Branch is a former journalist, and a current communications professional. Julian is a firm believer that persistence pays off, and democracy dies in darkness.