Asbestos is the generic/commercial name given to six naturally occurring fibrous silicates. Asbestos fibres are typically too small to be observed without a microscope.
Asbestos was widely used and desirable in industries and building products because of its physical and chemical properties.
The Forms of Asbestos
The two major groups of asbestos under which the 6 asbestos forms fall are serpentine and amphiboles (shown in Table 1). It is important to remember that all forms of asbestos have been linked to mesothelioma and cancer of the lung.
Table 1. The six forms of asbestos
|Amosite (brown asbestos)||Chrysotile (white asbestos)|
|Crocidolite (blue asbestos)|
Table 2. Summary of typical/historical asbestos use
|Building Product||Friability||Dates of Use (North America)|
|Mechanical insulation||high||1926 – mid 1970’s|
|Spray insulation||high||1935 – 1974|
|Texture coat||moderate – high||1950 – mid 1970’s|
|Floor tile||low||1950 – late 1970’s|
|Drywall taping compound||low – moderate||1945 – late 1970’s|
|Cement pipe||low||1935 – present|
|Brake linings||low||1940- present|
|Duct wrap||moderate – high||1920 – mid 1970’s|
|Textiles/gaskets||low – moderate||1920 – mid 1970’s|
|Roofing material||low||1920 – late 1970’s|
|Ceiling tiles||low – moderate||1950 – 1970’s|
|Cement board||low||1930 – present|
Canada Production and Trade
Canada has a long history of production, use and export of asbestos. The first Canadian asbestos mine was opened in 1874. Canada’s last asbestos mine ceased production in 2012. Canada still imports asbestos, asbestos friction materials, asbestos fabricated products like clothing, footwear, and construction materials containing asbestos like sheets, panels, tiles, tubes, pipes, pipe fittings.
Statistics Canada. Canadian International Merchandise Trade Database. Accessed 2015-04-01
Figure 1. Asbestos imports in Canada by value in Canadian dollars.
Exposure to asbestos may occur in some workplaces, and because of asbestos historic wide-spread use, the other known likely exposure sources of asbestos today are older asbestos containing products. One can get exposed to asbestos if the products containing asbestos deteriorate, are disturbed or damaged. According to , the occupations that are likely significantly exposed to asbestos today are specialty trade contractors, building construction (plaster and drywall installers, electricians, plumbers), and automotive repair and maintenance.
When asbestos fibres are released into the air, they are small enough that they can be inhaled or swallowed. When inhaled, they may lodge in the deep lung and get trapped in the lungs. If swallowed, they can become embedded into the digestive tract. Due to their chemical and physical properties, asbestos fibres are resistant to breakdown in the body. These fibres can cause scarring or inflammation. This inflammation typically continues even after exposure.
The International Agency for Research on Cancer reported that all the six forms of asbestos cause mesothelioma and cancer of the lung. The link to asbestos exposure and mesothelioma was identified as early as the 1930’s. Additionally, studies of asbestos and cancer have also shown that asbestos increases the risk of larynx and ovarian cancer. Asbestos has also been linked to cancers of the pharynx, stomach and colo-rectum (IARC 2012). Long have been observed between exposure to asbestos and the onset of lung cancer or mesothelioma.
Other non-cancerous outcomes that are associated with asbestos exposure include: asbestosis and non-malignant lung and pleural disorders.
Mesothelioma Incidence in Canada
Statistics Canada. Table 103-0550 –Figures present 3 year rolling averages. New cases of primary cancer (based on the February 2014 CCR tabulation file), by cancer type, age group and sex, Canada, provinces and territories, annual, CANSIM (database). (Accessed: 2014-07-29).
Figure 2. Incident rate of mesothelioma per 100,000 (1992-2010)
Factors That Affect Risk of Getting Asbestos-Related Disease
A person’s chances of developing asbestos related disease depend on how much asbestos one was exposed to and for how long one was exposed. Other factors like smoking increase one’s risk of developing lung cancer.
The suggested Canadian organizations’ links below provide more information pertaining to asbestos, asbestos exposure, how workers and others can protect themselves during exposure or when handling products containing asbestos, and asbestos related health effects:
- Health Canada,
- Canadian Centre for Occupational Health and Safety,
- CAREX Canada,
- Canadian Cancer Society,
The links to some of the Provincial government labour and health and safety services organizations that provide similar information are:
Government of Alberta; WorkSafe BC; Safe Work Manitoba; Work Safe NB; Service NL; Government of Nova Scotia; Ontario Ministry of Labour; Government of Prince Edward Island (WCB –PEI); La Commission de la santé et de la sécurité du travail (CSST) Quebec, Institut national de santé publique du Québec; Government of Saskatchewan; Government of Northwest Territories, Government of Nunavat and Government of Yukon.