About this Webinar: When Canadians turn on the tap for a drink of water or a shower, we take for granted that the water is safe. Few are aware that old asbestos cement water pipes still deliver water to millions of people. As these pipes age and deteriorate, asbestos erodes into the water and poses health concerns, including cancer. Dr. Meg Sears, Chair of the Board of Prevent Cancer Now, and board member Julian Branch will talk about the history of asbestos in water, the science behind ingested asbestos, and recent developments.

1. Asbestos cement water pipes
and ingested asbestos
Dr. Meg Sears and Julian Branch
Prevent Cancer Now
Presented to the
Canadian Cancer Survivors Network
September 28, 2023

2. Prevent Cancer Now
Canada’s scientific and public advocacy voice
on cancer prevention
“STOP cancer before it starts”

3. Asbestos cement water supply pipes
• 1930s to 1990s — Asbestos was used to reinforce
cement pipes for drinking water supplies
• The pipes contain up to 20% asbestos
• Sometimes called “transite” pipes (trade name)
• Asbestos cement (AC) pipes still deliver to water
to millions of people around the world
• Estimated lifespan of AC water pipes:
50 to 70 years
• Lifespan depends on water hardness and soil
stability

4. Asbestos in water
… some history
Reserve Mining Company began dumping asbestos-
contaminated iron ore tailings into Lake Superior in 1955.
• 1960s – asbestos fibres discovered in the lake, near
Duluth, MN
• 1970 – The United States Environmental Protection
Agency (EPA) was created.
• April 1972 – a landmark environmental trial began:
EPA v. Reserve Mining Co.
• April 1974 – the Reserve Mining Co. was ordered to
stop dumping tailings into the lake.
• The EPA launched a 20-year study of asbestos in water

5. Dr. Irving Selikoff
• Mount Sinai School of Medicine
• Chief government witness in the
EPA v Reserve Mining Co. trial
• For decades, Dr. Selikoff had been highlighting
the dangers of inhaling asbestos
• 1973 – Selikoff testified:
“In my opinion, the best explanation is ingestion
to explain the two, to three times increase in the
incidence of death from gastrointestinal cancer
among occupationally exposed workers.”
Image: Wikipedia

6. Dr. Selikoff in the media
1973 – Associated Press interview with Dr. Selikoff
• “There is a distinct public health hazard present in
Duluth and in other populations by drinking the
water and using it in other ways.”
• The latency period for asbestos related diseases
can be up to 40 years
• To do nothing would be to play ”a form of Russian
roulette, and we don’t know where the bullet is.”

7. Centre for Science in the Public Interest
Request to ban asbestos cement pipe
for use in the United States
• December 1973 — letter to the head of the EPA
• There were already 200,000 miles of AC water pipe
serving American consumers.
• It called for the EPA to “take prompt action to
eliminate the use of asbestos cement pipe for
drinking water supply.”
• The letter was cc’d to several Senators and
Congressmen

8. Pediatricians
• 1976 – American Academy of Pediatrics
published, Carcinogens in drinking water
• Re., asbestos:
“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.”

9. Aug. 1979 – EPA – “Exposure to asbestos
from drinking water in the U.S.”
• 365 cities surveyed
• More than 45% “were reported to have
significant concentrations of asbestos fibres in
the drinking water.”
• EPA measures asbestos in water in millions of
fibres per litre (MFL)
• Duluth, MN – up to 644 MFL
• Bishopville, SC – up to 547 MFL – Probable source
– asbestos cement pipe.
• Socorro, NM – up to two billion fibres per litre

10. 1980 – EPA “Ambient Water Quality
Criteria for Asbestos”
Asbestos is a known carcinogen when inhaled.
Asbestos is likely to be a human carcinogen when
ingested, given:
- ability of asbestos to induce malignant tumors in
different animal tissues,
- 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.

11. 1983 – Commentary — Asbestos in
Drinking Water: A Status Report
Joseph Cotruvo
• In the past there was some question regarding the
potential danger of ingesting asbestos. “The issue has
ripened considerably since then.”
• The issue of asbestos in drinking water is similar to
most environmental contamination issues. There is
never an absolute, unequivocal yes/no answer.
• Asbestos research has probably produced more hard
data than research on other topics.
• “Therefore, I believe we will be able to make
a good decision based on the current facts.”

12. Nov., 13, 1985 – Federal Register
EPA introduced a Recommended Maximum
Contaminant Level (RMCL) for asbestos in water.
“… asbestos has been shown to be a human carcinogen
through inhalation exposure and … asbestos may be
associated with an increased risk of gastrointestinal
cancer through occupational exposure.”
”An RMCL is proposed based upon the widespread
occurrence of asbestos in public water supplies, data
showing that asbestos is carcinogenic in humans and that
fiber lengths greater than 10 microns may be
carcinogenic through ingestion exposure.”

13. 1987 – “Report on Cancer Risks Associated
with the Ingestion of Asbestos”
Conclusion
• Insufficient direct evidence for a credible quantitative
cancer risk assessment of asbestos ingestion.
• “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.”
• “Several members … believe it is prudent, preventative
public health policy to recommend eliminating possible
sources of ingestion exposure to asbestos whenever,
and to whatever extent possible.”

14. 1992 - Asbestos Regulation
U.S. Environmental Protection Agency
• 1974 - U.S. Congress passed Safe Drinking Water Act
• 1992 - Asbestos regulation can into effect
• Maximum Contaminant Level (MCL) = 7 million
fibres per litre (MFL)
• The EPA cautioned that if levels of asbestos exceed
the MCL, then measures such as providing
alternative drinking water supplies “may be required
to prevent serious risks to public health.”

15. 1995 - EPA Fact Sheet
Health effects of asbestos in water
• “Long-term: Asbestos has the potential to cause
the following effects from a lifetime exposure
above the MCL: lung disease; cancer.”
• “Chronic: Asbestos has the potential to cause
lung disease from a lifetime exposure at levels
above the MCL.”
• “Cancer: Asbestos has the potential to cause
cancer of the lung and other internal organs
from a lifetime exposure ….”

16. 2023 - American Cancer Society
Asbestos and cancer risk
• “Swallowing asbestos: Asbestos fibres 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, and then swallow their saliva.”
• “Evidence from studies in both people and lab
animals has shown that asbestos can increase the
risk for some types of cancer.”

17. Meanwhile, in Canada …
Val-des-Sources — Formerly Asbestos, QC

18. A brief history of asbestos in Canada
• At its peak, Canada produced more than 40% of
the world’s chrysotile asbestos, 95% of which was
exported
• Chrysotile is the primary type of asbestos used in
the pipes
• Quebec accounted for approximately 80% of
Canadian asbestos production
• In the 2018 Canadian ban on asbestos and
products containing asbestos, asbestos cement
water pipes already in use were exempt

19. 1977 – Health and Welfare Canada survey
71 locations ~ 55% of Canadians
• Chrysotile was the predominant type of
asbestos identified in a survey of drinking
water supplies
• 5% of the population receives water with
chrysotile concentrations > 10 MFL
• 0.6% receives water containing > 100 MFL

20. 1977 Health and Welfare Canada
survey cont’d
• “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”
• Charts in the study show that there were high
levels of asbestos across Canada. The highest
levels were in Baie Verte, NL: concentrations in
the water as high as 1.8 billion fibres per litre

21. National Research Council AC water supply
pipe research
• 2003 - The National Research Council (NRC)
established a $30-million research centre at the
University of Regina
• 2003 to 2012 - The Centre for Sustainable
Infrastructure Research (CSIR) published 10 studies on
asbestos cement water pipes
• The studies refer to asbestos fibres in water as a
“health concern.” One study says asbestos fibres “pose
a hazard of cancer.”
• CSIR is no longer in operation
https://preventcancernow.ca/asbestos-cement-water-pipe-research-in-canada/

22. 2010 – Safety and Waste Management
of Asbestos Cement Pipes
• “Severe deterioration of the inner pipe surface, along
with sudden changes in hydraulic conditions, may cause
the release of asbestos fibers into drinking water.
• “… fewer health concerns about waterborne asbestos
fibers, there are still concerns about the inhalation of
airborne asbestos from showers, humidifiers, etc.
• “… concerns about the ingestion of fibers from drinking
water as well as the clogging of filter systems.”
• If not removed, AC pipes will further contaminate urban
spaces when area is dug up again.

23. 2010 – Bacteriological challenges to
asbestos cement water distribution
pipelines
• Severely deteriorated AC pipes also
– release asbestos fiber into the drinking water
– could pose a hazard of malignant tumors of the
gastrointestinal tract and other organs in consumers
• “Eventually, these asbestos fibers, along with the
biomass associated with them, will be released into the
drinking water stream and degrade drinking water
quality.”

24. 2023 – CTV’s W5 Investigation into
asbestos cement water pipes
• March 25, 2023 Something in the Water
• At least 85 communities still use AC pipes
• City of Regina has 600 km of AC water pipes
• During seven years of water testing, the City of
Regina has never detected asbestos
• W5 discovered 370,000 fibres per litre in one
sample of Regina water, using a U.S. laboratory.
• Dr. Arthur Frank says ingested asbestos can cause
a number of gastrointestinal cancers.

25. A problem created by a lack of federal
regulation
• In the wake of the W5 investigation, several
municipalities have said that they are meeting or
exceeding federal regulations for asbestos in water.
There is no Canadian regulation
• Very few municipalities test water for asbestos.
• e.g. – More than 75% of the water distribution pipes in
Weyburn, SK are asbestos cement. Weyburn does not
test the water for asbestos.
• Winnipeg, MB has 700 kms of AC water pipes. It last
tested water for asbestos in 1995.

26. 2023 – Health Canada

27. Is it safe to drink a known carcinogen?
World Health Organization and Health Canada:
there is no consistent, convincing evidence that
asbestos ingested through drinking water is harmful
to your health.
Very high, specific, difficult evidentiary bar
There is zero evidence of safety.
… you eliminate fibres mostly through the feces
Most tobacco smoke is exhaled, but it still causes
cancer.

28. 1989 - Health Canada review of
asbestos in drinking water
HC says that the assessment has been updated, but
the 1989 version remains online.
Whether inhaled or ingested, asbestos
particles distribute throughout the body
Fibres appear in the urine, and numerous organs
(kidney, heart, liver, spleen, adrenals, pancreas,
brain, prostate and thyroid). Even in the womb.
Fibres are seen in various tumours.

29. No drinking water
standard
A circular conundrum
“There is no consistent, convincing evidence
that asbestos ingested through drinking
water is harmful to your health”
No Canadian
standard method
to measure
asbestos in water
No ongoing Canadian research

30. 2016 - International Agency for Research
on Cancer (IARC)
• All forms of asbestos … are carcinogenic to humans
(Group 1).
• Working group split re. drinking water.
• Lung and stomach cancer are strongly correlated in
asbestos-exposed cohorts
• Co-carcinogen animal studies strongly positive for
cancer caused by asbestos ingestion.

31. IARC — international perspectives
• 2016 – Possible health risk from asbestos in
drinking water
• Apply the Precautionary Principle when dealing
with ingestion of asbestos
• “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.”

32. Asbestos ingestion and gastrointestinal
cancer: a possible underestimated hazard
• Agostino Di Ciaula (2017), Expert Review of Gastroenterology
& Hepatology, DOI: 10.1080/17474124.2017.1300528
• Gastric and colorectal cancer in exposed groups
• Experimental evidence … ingested asbestos fibres induce toxic
effects on the stomach, ileum and colon.
• … cross the placenta and enter foetal organs (including the
liver), and seem able to act as a co-carcinogen.
• Occupational studies suggest associations
between asbestos and intrahepatic cholangiocarcinoma
• … asbestos fibres could enter the liver and bile
through enteric absorption

33. Asbestos and Liver Cancer
(Intrahepatic Cholangiocarcinoma)
• Brandi and Tavolari report gastrointestinal tumors,
including liver cancer [intrahepatic cholangiocarcinoma
(ICC)]
• Asbestos fibers have been detected in the liver of patients
with ICC.
• … this could be explained in the light of particles’
translocation following ingestion/inhalation.
• In the liver, thin and long asbestos fibers could remain
trapped in the smaller bile ducts, … exerting their
carcinogenic effect for a long time, inducing hepatic
stem/progenitor cells (HpSCs) malignant transformation.
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7072580/

34. Prevent Cancer Now work to date
• Topic overview on PCN website
• Archive of the 10 National Research Council studies
looking into asbestos cement water pipes
• Discussion of carcinogenicity of asbestos that was
swallowed
• With the Canadian Environmental Law Association
(CELA), filed an environmental petition, for answers re.
asbestos cement water pipes from the federal
government
• Initiated a Parliamentary Petition on asbestos; now the
government must address the issues raised.

35. Actions following environmental
petition
• The Federal/Provincial/Territorial drinking water body
is reviewing the issue of regulating waterborne
asbestos in Canada. This could take three years.
• Statistics Canada is carrying out an inventory of
asbestos cement water pipes in Canada.
Target year 2025.
• Health Canada dismissed the 10 NRC studies because
they focused on infrastructure, not health.
• Nevertheless, federal government scientists warned
that ingesting asbestos can pose a hazard of cancer.

36. Next up: Measuring and managing
asbestos in water
No evidence of harm
IS NOT THE SAME AS
Evidence of no harm
Gastro-intestinal cancers are increasing rapidly in younger
Canadians.
Municipalities planning to replace AC pipes over several
decades could instead:
Prevent cancer
AND
Prevent ruin

37. Current and future situation
Regina SK. October 10, 2022

38. Repair bills
• Mar., 2018 - Water main breaks in the USA and
Canada. ”AC pipe breaks have increased 43%”
since 2012 – Utah State University
• AC water pipe more likely to fail catastrophically
than iron pipes – HDR Engineering, Bellevue, WA
• Smaller diameter asbestos cement pipes are
breaking at a higher rate than the larger diameter
asbestos cement pipes – HDR Engineering

39. Bellevue, WA
House slid down a hill, with AC pipe break flooding. January 2022

40. AC water pipes Agenda
Post- Auditor General and Parliamentary Petitions
ü Inventory/assessment of AC pipes (target 2024)
• Update science on cancer from ingestion of asbestos
• Institute standard measurement method for water
• Measure, manage, mitigate asbestos in drinking water
• Transparency
• High priority to replace pipes before “catastrophic
collapse”
• Waste disposal, including “prior and informed consent”
• “Asbestos Eradication Agency” as in Australia
For more info and further links:
https://preventcancernow.ca/taking-action/asbestos/

41. Thank you!
Contact:
info@preventcancernow.ca
Website:
https://preventcancernow.ca
Facebook: https://www.facebook.com/PreventCancerNow/
Twitter: https://twitter.com/PreventCancerNw
Comments
Questions?

42. Canadian Cancer Survivor Network
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