Asbestos cement pipes have been around since the early 1900’s. The material was invented in 1902 by Austrian Ludwig Hatschek. An Italian by the name of Adolfo Mazza developed a process to mass produce asbestos cement water pipes in 1911, which sent global sales soaring. Asbestos was prized for its high tensile strength, when mixed with cement. The pipes –  20% asbestos and 80% cement when new – were being sold around the world. They were lighter and cheaper than cast iron pipes, and at the time thought to be virtually impervious to deterioration. Unfortunately, the last part didn’t come true.

The pipes, which now encircle the globe, have reached the end of their useful lives, and in recent decades have been failing with increasing frequency. They are especially impacted by soft water, and expansive clay soil, and are breaking in record numbers. Because of a lack of regulation surrounding asbestos in water, very few jurisdictions even bother to test for the microscopic fibres. The latency period for asbestos related disease can be up to 40-years. Meanwhile, largely unexplained gastrointestinal cancers are soaring in young adults.

Reserve Mining

The genesis of this story is in the United States. In 1973, the U.S. government took the Reserve Mining Company to court, in what would become a landmark environmental trial. For decades, Reserve Mining had been dumping iron ore tailings into Lake Superior, the largest of the Great Lakes between The U.S. and Canada. When the water was tested for asbestos near Duluth, Minnesota results showed it contained 644 million fibres per litre (644 MFL). Reserve Mining was ordered to stop dumping its tailings into Lake Superior. The discovery, and the ensuing lawsuit sparked a two-decade long investigation by the fledgling Environmental Protection Agency (EPA).

EPA

Dr. Irving Selikoff, widely regarded as the foremost expert in the world on asbestos related diseases at the time, testified at the Reserve Mining trial. His testimony was the first time the focus was on the ingestion of asbestos fibres rather than inhalation. “Secondly, although I stated yesterday that there are a number of routes, including hemotogenous, whereby fibres could influence the gastrointestinal tract, in my opinion the best explanation is ingestion to explain the two to three times increase in the incidence of death of gastrointestinal cancer among occupationally exposed workers. So, in that sense, although there is no absolute proof, the kind that we ordinarily would want, there is in my opinion, a very reasonable probability to state that this is the case,” Selikoff testified more than a half century ago.

Selikoff’s testimony wasn’t lost on environmental groups. In December 1973, the Centre for Science in the Public Interest wrote to the then head of the EPA demanding that it prohibit asbestos cement water pipes. In its letter, the group said there were an estimated 200,000 miles (321,000 kms) of asbestos cement water pipes already installed in America. “As Dr. Selikoff of Mount Sinai and Dr. Wagoner of the National Institute of Safety and Health have recently testified in the Duluth case, there is ample reason to believe that ingestion of the major varieties of asbestos leads to increased risk of gastrointestinal cancer.” It is estimated there are close to one-million kilometres of ageing asbestos cement water pipes in the United States today.

One of the first groups to weigh in on the potential dangers of ingested asbestos was the

American Academy of Pediatrics. In a 1976 study, entitled Carcinogens in Drinking Water – Asbestos it stated “There appears to be no doubt that there is an increased frequency of human gastrointestinal cancer after occupational exposures – presumably from asbestos that has been swallowed.”

The first step for the EPA was to determine whether there was actually widespread asbestos in American water. In 1979, it produced a study entitled Exposure to Asbestos from Drinking Water in the United States. It looked at 365 municipalities. “Of the 365 cities, 165 or 45.5% were reported to have significant concentrations of asbestos fibers in the drinking water.” Some of that was attributed to asbestos cement water pipes.

The EPA now turned its attention to whether it was harmful to swallow asbestos. One of the most important findings of the 1980 study Ambient Water Quality Criteria for Asbestos was that ingested asbestos does pass through the human gastrointestinal tract. “Asbestos is a known carcinogen when inhaled. The demonstrated ability of asbestos to induce malignant tumors in different animal tissues, the passage of ingested fibres 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,” it reads.

America wasn’t the only country putting asbestos in water under the microscope. In the late 1970’s Canada was also carrying out its own survey of 71 municipalities. Health Canada published Asbestos and Drinking Water in Canada in 1981. One of the cities highlighted in the report is Winnipeg, Manitoba. Under the sub-heading of Contribution of Asbestos-Cement Pipes it reads “At points in the Winnipeg distribution, values as high as 6.5 MFL were found. These data provide a statistically valid indication that erosion of asbestos-cement pipes is taking place.” There are currently 740 kilometres of old asbestos cement water pipes in the Manitoba capital. Winnipeg water hasn’t been tested for asbestos since 1995.

The issue of ingested asbestos has, for decades, stirred passionate debate.

Another report on asbestos in water came out of the United Kingdom in 1983. Asbestos Fibres in Drinking Water, authored by B.T. Commins, had a decidedly different take on the issue. “A great deal of time and money has been spent in the last 10 years or so in evaluating the subject, and now it would seem that the controversy has for all practical purposes ended, and maybe the issue can be regarded as essentially a non-problem. Perhaps research effort should now be sensibly diverted into various other environmental issues.”

Someone at the EPA didn’t get the message because in 1985 it published Research and Development, Drinking Water Criteria Document for Asbestos: “The possibility of an elevated risk of cancer of the stomach and pancreas must be considered as suggestively associated with ingestion of asbestos in water, and thus not inconsistent with a hypothesis that ingested asbestos by the drinking water route might have tumor carcinogenic potential. The strong evidence of GI tract cancer resulting from inhalation exposure and the assumed swallowing of inhaled fibres as the ingestion mode, clearly demonstrates that under certain conditions, asbestos has a definite potential for human carcinogenicity by ingestion,” reads the almost 200-page study.

By 1987, the issue was in the hands of the powerful U.S. Department of Health and Human Services. It released  a study entitled Report on Cancer Risks Associated with the Ingestion of Asbestos: “Even if the increased rate of cancer is less than 10% 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,” it reads. The study goes on to say “Several of the members of this working group believe it is prudent, preventative public health policy to recommend eliminating possible sources of ingestion exposure to asbestos whenever and to whatever extent possible.”

In 1992, the U.S. Environmental Protection Agency would regulate asbestos in water. The Maximum Contaminant Level (MCL) was set at seven million fibres per litre (7 MFL). A 1992 EPA fact sheet says there was a very clear reason why the MCL was established at 7 MFL.  “Set at 7 MFL to protect against cancer,” reads the document. More fact sheets followed in 1995. The EPA

Fact Sheet – National Primary Drinking Water Regulations outlines long-term consequences of drinking asbestos. “Long-term health effects – Asbestos has the potential to cause the following effects from a lifetime exposure at levels above the MCL: lung disease; cancer.” “Asbestos cement pipes in water supply systems” are listed as a possible source.

Curiously, the only health effect associated with ingested asbestos on the current EPA National Primary Drinking Water Regulations is an “Increased risk of developing benign intestinal polyps.” “Decay of asbestos cement in water mains” is still listed as the primary source of asbestos in water.

The American Cancer Society addresses the issue on the asbestos and cancer risk page of its current website. “Swallowing asbestos: Asbestos fibers can also be swallowed. This can happen when people eat or drink contaminated food or liquids (such as water that flows through asbestos cement pipes). It can also occur when people cough up asbestos they have inhaled, then swallow their saliva.”

That sentiment is echoed in a 2004 one-pager produced by the Environmental Protection Agency, which perfectly illustrates its rationale for regulating asbestos in water. “The primary reason for concern about drinking water containing asbestos fibers is the association between occupational asbestos exposure and gastrointestinal cancer shown in a number of occupational epidemiology studies, reads Use of Asbestos Cement Pipe. “Although the asbestos worker is exposed to asbestos it has been clearly demonstrated that a high percentage of inhaled fibers deposited in the lung are cleared and swallowed. So, they are also exposed to ingested fibers.”

Canada

Canada made the decision not to regulate asbestos in water in 1989. It had decided to follow the lead of the World Health Organization (WHO), which had determined that there is “no consistent, convincing evidence” that ingested asbestos is harmful. Canada has not established a Maximum Acceptable Concentration (MAC) for asbestos. As a result, very few Canadian municipalities choose to even test the water for asbestos.

Regina, Saskatchewan has so much old asbestos cement water pipe, and it has such a high break rate, due to its expansive clay soil, that in 2003, with much fanfare, the federal government, the provincial government, the city, and the University of Regina announced a $30-million National Research Council (NRC) facility, which would go on to produce 10 very specific, very detailed studies on asbestos cement water pipes. While the pipes are not mentioned in the original three-page news release, Regina was referred to in literature promoting the facility as a “living laboratory.” The first study produced in 2005, entitled Failure Conditions of Asbestos Cement Water Mains in Regina, made it abundantly clear that Saskatchewan’s capital city had a major problem. “In the City of Regina approximately 531 km, or two-thirds, of the water mains are asbestos cement (AC) pipes. These pipes are experiencing more and more failures in recent years and account for almost all of the water main breaks in the city,” reads the first sentence in the Introduction. On the top of page two, the study refers to asbestos fibres in the water, leaching from old pipes, as a “health concern.” Several other NRC studies would use these exact same words to describe the situation. It wasn’t until the 2010 release of Bacteriological Challenges to Asbestos Cement Water Distribution Pipelines that the NRC would define health concern. “Severely deteriorated AC pipes also released asbestos fiber into the drinking water and could pose a hazard of malignant tumors of the gastrointestinal tract and other organs in consumers.” The report goes on to say it’s a matter of if, not when, the pipes will break down and release asbestos into the water. “Eventually, these asbestos fibres, along with the biomass associated with them, will be released into the drinking water stream and degrade drinking water quality,” it reads.

Apart from warning  of cancer, the NRC studies reveal a disturbing truth about the makeup of the pipes. You will recall that new asbestos cement water pipes are made up of approximately 20% asbestos, 80% cement. “Asbestos fibres and quartz particles are extremely resistant to weathering and normally remain intact, therefore, the relative content of these two become elevated in the deteriorated pipe,” reads the 2011 study entitled Biodeterioration of Asbestos Cement (AC) Pipe in Drinking Water Distribution Systems. The troubling discovery is confirmed in a 2019 presentation from WorkSafe BC. “Aged, failing pipe can be up to 80% asbestos,” it reads.

The Canadian federal government would inject another $4-million into the facility in 2009. The research centre, which had been billed as “permanent” quietly closed its doors in 2013, about one-year after people started asking questions.

I was curious to know whether the NRC had followed up on the 10 studies warning of health concerns, and cancer, so in late 2021, I reached out to the federal agency in charge of science and research in Canada to ask a few elementary questions related to asbestos cement water pipes. The response was illuminating. “NRC does not hold any data on asbestos cement water pipes,” reads the reply.

The federal government communication on this issue gets even more muddled when Health Canada is asked how it is that the National Research Council studies say that drinking asbestos can cause cancer, yet Health Canada maintains there is insufficient evidence to show that ingested asbestos is harmful. The NRC reports “cannot be used as evidence that asbestos ingested through drinking water is a health concern. These reports are about infrastructure, namely addressing various aspects of asbestos-cement pipes. The reports are not focussed on health issues and studies cited in the reports have methodological limitations from a health perspective that prevent the study authors from estimating and drawing conclusions on health risks,” said Health Canada in response to a formal 2022 petition.

In April of this year, Regina city council unanimously passed a motion calling on administration to expedite the replacement of as many as 600 kilometres of old asbestos cement water pipes in the city. At the current rate, it will take up to 60-years. It was revealed at the council meeting dealing with the issue that there are, on average, 210 asbestos cement water pipe breaks per-year in Regina, and that at the current replacement rate the city is barely keeping up with them. A decision is expected in the fall.

Canada’s reluctance to acknowledge the health concerns associated with swallowing asbestos is best explained by a 1977 Science Council of Canada report entitled Regulatory Processes and Jurisdictional Issues in the Regulation of Hazardous Products in Canada. The report, written at a time when asbestos was still being mined and produced in Canada, notes that there are six types of asbestos which are of economic importance. It focuses on chrysotile asbestos. “Of the six, chrysotile constitutes 95 per cent of world production. Canada produces over 40 per cent of the world’s production of chrysotile, 95 per cent of which is exported,” reads the report.

It’s not just North America which is still using the pipes. There are an estimated 40,000 kilometres of asbestos cement water pipes still in use across Australia. Australia has established the Asbestos Safety and Eradication Agency to deal with the issue. In 2017, the agency released a report entitled Case Studies of Asbestos Water Pipe Management Practices. In the introduction, the report makes it clear that Australia is okay with drinking asbestos. “Asbestos containing (AC) cement has been used extensively in Australia, and whilst no evidence suggests this creates a risk to drinking water, its aging nature means many of the AC pipes are likely to need remediation in the next ten to fifteen years.”

There are an estimated nine-thousand kilometres of old asbestos cement water pipes in New Zealand. Soft water and earthquakes in recent decades have wreaked havoc on the underground water infrastructure in parts of New Zealand. In 2022, the University of Otago investigated water main breaks in Christchurch and Temuka, New Zealand. An illustration in the report concerning the latter shows a screen on a tap clogged with what is described as a “white fibrous paste,” following a 2017 asbestos cement water main break in the community. The report highlights a lack of regulation in New Zealand. “These contamination events revealed significant gaps in the regulatory framework and water monitoring protocols in New Zealand including issues surrounding the reporting of values exceeding the Maximum Acceptable Value (MAV) and a lack of direction in the current standards with reporting of non-priority contaminants (like asbestos), reads the report. “There are no regulatory limits in place to determine ‘safe’ levels of exposure, nor a mandate to test its presence in the water supply regularly,” it continues.

Images of clogged screens on taps are also available from Brockway, Pennsylvania where asbestos cement water pipes are deteriorating. According to a 2023 drinking water quality report, the concentration of asbestos in Brockway water reached an astronomical 1.3-billion fibres per litre. Residents of Regina, Saskatchewan are now also being warned about a build-up of sediment in screens on their taps. These are also known faucet screens or faucet aerators. They are designed to introduce air into the water, catch debris, and provide a steady, splash-free stream of water.

The United Kingdom takes a similar view that it’s okay to drink asbestos fibres. “There has been little convincing evidence of the carcinogenicity of ingested asbestos in epidemiological studies of populations with drinking water supplies containing high concentrations of asbestos,” reads a 2002 Drinking Water Inspectorate (DWI) study entitled Asbestos Cement Drinking Water Pipes and Possible Health Risks Review for DWI. The study concludes “Although many countries in the world, including many European countries, still have asbestos cement water pipes, there appears to be no concern for the health of consumers receiving the water and no programmes to specifically replace asbestos cement pipes for this reason.”

A March 2026 update with the DWI elicited a similar response a quarter century later. “We are currently not aware of any evidence that asbestos in water is posing a risk to human health,” writes DWI Principal Inspector Tim Williams, in response to questions about a lack of regulation in the UK. There are an estimated 37,000 kilometres of old asbestos cement water mains stretching across the United Kingdom. There is evidence to show that they are experiencing an increase in failures. “There will be some historic pipes in use,” writes Mr. Williams. “but the inspectorate does not hold any data on how many kilometres of AC mains are in place.”

Changing Attitudes

I am pleased to report that there is evidence that attitudes are shifting, and concern is growing. A 2016 study out of Italy entitled Possible Health Risks from Asbestos in Drinking Water contains a rather alarming conclusion.  “Furthermore, the exposure to asbestos by ingestion could explain the epidemiological finding of mesothelioma in subjects unexposed by inhalation. In conclusion, several findings suggest that health risks from asbestos could not exclusively derive from inhalation of fibres. Health hazards might also be present after ingestion, mainly after daily ingestion of drinking water for long periods.” The ten-year-old study called for more investigation in this area. Italy has close to 100,000 kilometres of ageing asbestos cement water pipes. Earthquakes in recent decades have exacerbated breakage.

One of the more obscure, but powerful studies is from Norway. 2005’s Cancer of the Gastrointestinal Tract and Exposure to Asbestos in Drinking Water Among Lighthouse Keepers looks at lighthouse keepers who get their drinking water from cisterns after it runs off the asbestos cement tile roofs. The study looked at 726 lighthouse keepers over several decades. “Risk of stomach cancer was elevated in the whole cohort,” reads the results. The Conclusion, which follows, states “The results support the hypothesis of an association between ingested asbestos and gastrointestinal cancer risk in general and stomach cancer risk specifically.”

Jurisdictions around the world are slowly coming to grips with the issue, and accelerating the replacement of old asbestos cement water pipes. In March of this year, Scottish Water announced plans to speed up the replacement of approximately six-thousand kilometres of asbestos cement water mains in Scotland within 15-years. Malaysia, which has almost 40,000 kilometres of asbestos cement water pipe plans to replace it by 2040. In Kenya, a news release posted to the Government Advertising Agency website last September boasts of a plan to replace ageing asbestos cement water pipes. “Scientists believe asbestos used in roofing and piping may be linked to gastrointestinal cancers in humans, reads the release. Cabinet Secretary for Water, Sanitation and Irrigation, Eric Mugaa is quoted in the release as saying “Asbestos pipes are believed to be responsible for some of the health problems we are facing, including cancer, and therefore we want to replace them.”

In its latest report on asbestos in drinking water in 2021, the World Health Organization maintains there is insufficient evidence to show that ingested asbestos is harmful. Earlier this year, through a spokesperson, the WHO said there are no plans for further updates on its position.

Precautionary Principle

The stance flies in the face of a 2004 WHO report on the precautionary principle. The report entitled The Precautionary Principle: Protecting Public Health, the Environment and the Future of our Children contains a telling sentence in the Foreword. “Irreparable mistakes must be avoided, such as those related to tobacco or asbestos, when people waited for definitive evidence far too long before springing to action.”

I am in full agreement with that statement. The World Health Organization needs to stop pretending that there is no evidence that swallowing asbestos is harmful, and spring into action.