Scientific data

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In Thailand, tests conducted in 2008 show that chrysotile cement roofing tiles are stronger and more durable than those that do not contain chrysotile. In Canada, studies found no evidence of higher incidence of asbestos-related diseases in chrysotile mining towns when compared with urban residents. In the US and the UK, studies have found that people drinking water that passes through chrysotile cement water pipes have no increased risk for cancer. In Australia, Austria, and Germany, studies found that the asbestos fibre concentration in areas using asbestos cement roofing tiles is not statistically higher than in areas where no asbestos cement tiles are used. 

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Scientific cases by countries

Thailand
In Thailand, asbestos has been used for more than 70 years. Crocidolite, being a highly toxic substance, has been banned under the Hazardous Substance Act B.E. 2535 (1992).

Today, only chrysotile is used in the country. Chrysotile accounts for most of imported asbestos. 90% of imported raw chrysotile fiber is used in high density chrysorile-cement products, i.e. roof tile and cement pipe. The others are found in production of brake and clutch (8 %) and in production of vinyl floor tile, gasket, or heat insulating materials (2%). In 2001, 17 factories using asbestos with 1,710 workers registered at the Department of Industrial Work, Ministry of Industry.

According to the article Asbestos in Thailand authored by Somkiat Siriruttanapruk and Sasitorn Taptagaporn, Ministry of Public Health:

“Asbestosis or other asbestos related diseases have never been reported to the surveillance schemes or the Workmen’s compensation fund in this country. Only few pleural thickening cases were notified from a survey conducted by the Division of Occupational health. The survey was carried out in 24 factories in 1987. The data showed that 13 out of 701 workers had pleural thickening from standard chest x-ray. Eight of them had worked for more than 10 years. Unfortunately, they have never been followed up since then. Apart from this study, another 3 studies were conducted afterward. However, no asbestos related disease cases were detected from the studies in spite of high exposure level. This may be due to short duration of exposure among workers (average working duration was 5.2 years).”

Thailand academic laboratory report:

Canada
Study comparing health effects in residents of chrysotile mining towns, where levels are from 200 to 500 times higher than in most North American cities, to those seen in urban residents. In spite of higher levels in these mining towns, no evidence of higher asbestos-related diseases were found. The author concludes: "These observations should provide reassurance that exposure to chrysotile asbestos from urban air or in public buildings will not produce detectable disease".

This is in agreement with other reports on residents of chrysotile mining towns in Québec, which have consistently failed to demonstrate excess respiratory disease incidence.

These are:

  • McDonald AD, and McDonald JC (1980). Cancer 46(7): 16 50-1656.
  • Siemiatycki J. (1982). Health effects on the generalpopulation (mortality in the general population in asbestos mining areas). Proceedings, World       Symposium on Asbestos, Montreal, 25-27 May, pp.337-348.
  • Pampalon R, Siemiatycki J, et Blanchet M, (1982). Pollution environnementale par l'amiante et santé publiqu e au Québec. Union Médicale du Canada       111(5): 475-
  • 489.McDonald JC, (1985). Health implications of environmental exposure to asbestos. Environmental Health Perspectives 62:319-328.
  • (Churg, A., American Review of Respiratory Disease, 134 (1):125-127, 1986)

"Considering all of the above data together, we conclude that asbestos fibre concentrations in the ambient air are extremely low. Counts of fibres longer than 5 microns taken by electron microscope are often less than 0.001 f/cc. If we consider the fibres that would be seen by an optical microscope, it is extremely rate in Ontario to have concentrations greater than 0.001 f/cc. The recent Ontario data suggest that fibre levels are lowest where population density is lowest, although the earlier Ontario data did not reveal this relationship. In Chapter 9 we conclude that the health risks presented to building occupants from exposure to 0.001 optically visible fibres per cubic centimetre is not significant. It follows that the fibre levels discussed in this section present a clearly insignificant health risk. We see no reason to worry about the health effects of the prevalent level of asbestos fibres in the outdoor air in Ontario". (Report of the Royal Commission on Matters of Health and Safety Arising from the Use of Asbestos in Ontario, Eds. JS Dupré, JF Mustard, RJ Uffen, Published by the Ontario Ministry of the Attorney General 2:666, 1984)

United States
A study of 15 water supply systems in the State of Illinois (U.S.A.) where some asbestos cement pipes were up to 50 years old, and where the water was non-aggressive to moderately aggressive, showing no significant differences before and after passing through the asbestos-cement pipe network. (Hallenbeck, W.H., Chen, E.H., Hesse, C.S., Patel-Mandlik, K., and Wolff, A.H., Journal of American Water Works Association, 70(2):97-102, 1978)

“Some areas in Florida have been receiving drinking water through asbestos-cement pipes for 30-40 years. The authors mention: "No evidence for an association between the use of A/C pipes for carrying drinking water and deaths due to gastrointestinal and related cancers was found in this study". (Millette, J.R., Craun, G.F., Stober, J.A., Kraemer, D.F., Tousignant, H.G., Hidalgo, E., Duboise, R.L., and Benedict, J., Environmental Health Perspectives, 53:91-98, 1983)

The site of the study was Puget Sound region of Western Washington, and the State's three largest metropolitan areas (Everett, Seattle and Tacoma) were used for comparison. Everett was the " high exposure municipality", where asbestos levels ranged from 37.2 to 556 million fibres per liter. Seattle and Tacoma had relatively low concentrations, averaging 7.3 million fibres per liter. The three metropolitan areas were subdivided into census tracts grouped by asbestos concentration. Data on cancer incidence were obtained from a surveillance registry; cancer mortality information came from death certificates. Duration of exposure to asbestos in drinking water was estimated and divided into long term (greater than 30 years) versus short term (less than 30 years) groups. Following the analysis of the results, the principal investigator, Dr. Lincoln Pollisar of the Fred Hutchinson Cancer Research Center, concluded that: "Results of this study and prior studies of cancer in relation to waterborne asbestos are inconsistent, and provide little evidence that asbestos in community water supplies has altered the risk of any cancer". (Polissar, L., Severson, R.K., Boatman, E.S. and Thomas, D.B., American Journal of Epidemiology, 116(2):314-328, 1982)

Germany
Data pertinent to the extent of possible emissions from A/C construction products and the air concentrations in various countries have been obtained at different times from 1980 to 1997.

In Germany, the study of emission on coated and uncoated and coated roofing materials revealed low asbestos fibre concentrations, even though severe corrosion was observed on uncoated asbestos cement roofs and a considerable quantity of materials containing asbestos could be removed by blowing and suction. Yet, asbestos fibre concentrations that were measured in populated areas were well below the level considered acceptable by German health authorities, i.e.: clearly below 1000 fibres per cubic metre. (Teichert U, Staub Reinhaltung der Luft. 46:432-434, 1996)

Austria
In Austria, a comparison of the asbestos fibre concentrations in those areas with and without asbestos cement roofing (< 0.0001 f/ml) led to the conclusion that there is no statistically significant connection between the use of asbestos cement materials and the asbestos fibre concentrations found in the various measurement areas. (Felbermayer, W., and Ussar, M.B., Research Report: Airborne asbestos fibres eroded from asbestos cement sheets, Institute fur Umweltschutz and Emissionsfragen, Leoben, Austria, 1980)

United Kingdom
In this review article, the author concludes: "it would thus seem highly unlikely that the asbestos-cement pipe distribution system makes any biologically significant contribution to the asbestos content of water passing through it". "It is highly improbable that asbestos release from asbestos cement pipes is relevant to the development of cancer." (MacRae, K.D., Journal of the Royal College of Physicians of London 22(1):7-10, 1988)

Australia
In Australia, possible contribution from asbestos cement roofing materials of school buildings to the air concentrations in the vicinity of these buildings was studied. It was found that measurements were mostly < 0.0002 f/ml. (Safety & Welfare of Western Australia, Report of the Working Party on Asbestos Cement Products, 1990)

 

Additional Resources and Publications

Selected occupational risk factors 
Concha-Barrientos et al., 2004

A comparison of the risks from different materials containing asbestos 
Health and Safety Executive (HSE), UK, 2006

Annex 2 to Paper HSC/06/55
Health and Safety Executive (HSE), UK, 2006

Occupational exposure to asbestos and man-made vitreous fibres and risk of lung cancer: a multicentre case-control study in Europe
Carel, R. et al., 2006

Three decades of pleural cancer and mesothelioma registration in Austria where asbestos cement was invented 
Neuberger, M. and Vutuc, C., 2003

The risk of mesothelioma from exposure to chrysotile asbestos
Yarborough, C. M. (2007)

The expected burden of mesothelioma mortality in Great Britain from 2002 to 2050
Hodgson, J.T. et al. (2005)

Asbestos in water: How to Address Non-standard Samples of Industrial and Other Effluents 
Ehrenfeld, F. (2009) 

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