Artificial UV Radiation Resources

Package summaries

• Construction [PDF]
• Health Care [PDF]
• Mining [PDF]
• Welder [PDF]

Tools

• eWORK

Publications

• Peters CE, Ge CB, Hall AL, Davies HW, Demers PA. “CAREX Canada: an enhanced model for assessing occupational carcinogen exposure.” Occup Environ Med 2015;72(1):64-71.

Videos

• CAREX Occupational Estimates Overview
• CAREX eWORK Tool Overview

Exposure Reduction

Our team has performed a detailed scan of exposure control resources and assembled a compilation of key publications and resources. These are organized by type of exposure (environmental or occupational) and by specificity (general or carcinogen-specific). Please visit our Exposure Reduction Resources page to view.

We also recommend exploring the Prevention Policies Directory, a freely-accessible online tool offering information on policies related to cancer and chronic disease prevention. Providing summaries of the policies and direct access to the policy documents, the Directory allows users to search by carcinogen, risk factor, jurisdiction, geographical location, and document type. The Canadian Partnership Against Cancer has also developed an ultraviolet radiation policy pack to support evidence-informed actions for local and provincial/territorial governments. For questions about these resources, please contact a member of the Prevention Team at the Canadian Partnership Against Cancer at [email protected].

Asbestos Environmental Exposures

Asbestos Environmental Exposures

Overview

In the environment, the primary route of exposure is by inhaling air contaminated with asbestos. People may be exposed to higher-than-average levels of asbestos in air if they use asbestos-containing products, or live or work in buildings with deteriorating asbestos insulation or that have undergone poorly performed asbestos removal.[1]

Cancer Risk Estimates

Potential lifetime excess cancer risk (LECR) is an indicator of Canadians’ exposure to known or suspected carcinogens in the environment. When potential LECR is more than 1 per million in a single pathway, a more detailed risk assessment may be useful for confirming the need to reduce individual exposure. If measured levels of asbestos in relevant exposure pathways (outdoor air and indoor air) decrease, the risk will also decrease.

Potential LECR due to exposure to asbestos is calculated by multiplying lifetime hourly concentration by a unit risk factor. More than one cancer potency factor may be available, because agencies interpret the underlying health studies differently, or use a more precautionary approach. Our results use unit risk factors from Health Canada, the US Environmental Protection Agency (US EPA), and/or the California Office of Environmental Health Hazard Assessment (OEHHA).

The calculated lifetime hourly concentrations and LECR results for asbestos are provided in the tables below. For more information on supporting data and sources, click on the Methods and Data tab below.

Calculated Lifetime Hourly Concentrations

Lifetime Excess Cancer Risk (per million people)

*LECR based on average intake x cancer potency factor from each agency

Compare substances: Canadian Potential Lifetime Excess Cancer Risk, 2011

The data in this table are based on average intake and Health Canada’s cancer potency factor, assuming no change in measured levels. When Health Canada values are not available, United States Environmental Protection Agency values are used.
Click the second tab to view LECR data. 

**Exposure not applicable: For indicated pathways, substance not present, not carcinogenic, or exposure is negligible
**Gap in data: No cancer potency factor or unit risk factor, or no data available
IARC Group 1 = Carcinogenic to humans, IARC Group 2A = Probably carcinogenic to humans, IARC Group 2B = Possibly carcinogenic to humans

NOTE: Chromium (hexavalent) estimates assume that 5% of total chromium measured in outdoor air is hexavalent and 8% total chromium measured in indoor dust is hexavalent. 

Potential LECR assumes exposure occurs at the same level, 24 hours per day, for 70 years. This is rarely true for any single individual, but using a standard set of assumptions allows us to provide a relative ranking for known and suspected carcinogens across different exposure routes. While ongoing research continually provides new evidence about cancer potency and whether there is a safe threshold of exposure, our approach assumes there are no safe exposure levels.

Mapping

Exposure to asbestos may have occurred historically in communities close to asbestos mines, and may still be occurring when waste piles containing asbestos are present.[13,14,15] In the past, people who lived near manufacturing facilities producing insulation with asbestos-contaminated vermiculite from Libby, Montana may have been exposed;[16,17,18] and recent studies also suggest that exposure might occur when naturally occurring asbestos deposits are disturbed.[19] Vermiculite produced by the Libby Mine in Montana from the 1920s-1990 and sold as Zonolite® Attic Insulation may contain amphibole asbestos,[20] and potential exposures may occur in homes where Zonolite® insulation is disturbed.

Selected Asbestos Mines, Historic Vermiculite Processing Facilities and Potential Naturally Occurring Asbestos Deposits

Canadian Distribution of Libby Ore Shipments from 1964-1990 (in tons)[21]

Asbestos Production

Exposure to asbestos may have occurred historically in communities close to asbestos mines, and may still be occurring when waste piles containing asbestos are present.[12,13,14] In the past, people who lived near manufacturing facilities producing insulation with asbestos-contaminated vermiculite from Libby, Montana may have been exposed;[15,16,17] and recent studies also suggest that exposure might occur when naturally occurring asbestos deposits are disturbed.[18] Vermiculite produced by the Libby Mine in Montana from the 1920s-1990 and sold as Zonolite® Attic Insulation may contain amphibole asbestos,[19] and potential exposures may occur in homes where Zonolite® insulation is disturbed.

The last two operating asbestos mines in Canada – both in Quebec – closed down in 2012.

Annual Asbestos Production in Canada: 1886 to 2011[22,23,24]

*Data not available in 1987 for QC, BC, NL

Known asbestos producers and mine locations in Canada 1943 to 2006[23]

Vermiculite Processing

In 1916, the world’s largest deposit of vermiculite was discovered near Libby, Montana. The vermiculite was mined primarily for use as an insulating material. Crude (or raw) vermiculite was shipped from the mine to processing plants across the US and in Canada, where it was exfoliated using high temperatures causing it to expand significantly. In 1935, a report from the US Bureau of Mines noted the presence of a series of amphibole asbestos dikes, up to 10 feet thick intersecting the vermiculite deposit. Over the entire operating life of the Libby mine (1921 to 1992), the vermiculite extracted and shipped for processing was contaminated with this particularly carcinogenic form of asbestos.[23,25]

Vermiculite was mined and processed commercially in Canada only for a very short time (1956, 1957, and 1966) and in very small quantities at a location near Stanleyville, Ontario. All other vermiculite processed in Canada was imported from the United States, predominantly from Libby mine, or from South Africa (presumed to be uncontaminated).

Available data sources regarding Canadian imports of vermiculite include: 1) general information on all imports to Canada from South Africa or the United States reported in mineral yearbooks from the United States Geological Survey and Natural Resources Canada, and (2) invoices of vermiculite shipments from the Libby Montana Mine to companies in Canada from the United States Environmental Protection Agency. See more information about each data source below.

Canadian Imports Reported in Mineral Yearbooks (CAN & US)

The graph below shows tonnes of crude vermiculite imported from the US and South Africa for years with available data. USGS Bureau of Mines reports note that vermiculite from the Libby mine was being exported to Canada for processing as early as 1935 (Winnipeg, MB and Paris, ON).[25] See the map for more information on processing sites in Canada.

Annual Imports of Crude Vermiculite: 1963 to 1992[23,25]

Libby Mine Invoices

The United States Environmental Protection Agency (EPA) has compiled a database documenting W.R. Grace invoices for shipments from the Libby Mine from 1964 to 1990.[26] The database includes company name, shipping destination, and total tonnage shipped. The EPA database may not include every shipment made during this time.

Although the number of sites and amount of ore received may be understated by invoices in the database, the EPA has investigated sites in the United States thought to have received ore to determine if remediation activities are necessary. Investigations have not been carried out for Canadian shipment locations.

The following table reports W.R. Grace invoices for shipments of vermiculite from Libby Mine to Canadian locations from the EPA database. No information is available on the end uses of vermiculite shipped to reported Canadian locations; some may have been shipped directly to facilities engaged in vermiculite processing, while others may have been subsequently transported to other locations for other intended purposes.

At least 8,252 shipments of vermiculite were made from Libby, MT to locations in Canada; the majority of shipments and total tons to Ontario, Quebec, and Alberta. See the table below and map for more information on shipment locations in Canada.

Invoices from Libby, MT to Canadian Locations: 1964-1990

Home Insulation

The number of homes in Canada insulated using Zonolite® is unknown; however, it is estimated to be present in 3% of low-rise houses across Canada, or 242,000 homes in residential neighbourhoods, including First Nation Housing, and on Canadian military bases.[27]

From 1977-1986 the Canadian Home Insulation Program (CHIP) provided grants to homeowners for improving the energy efficiency of their homes. During this time 2,592,392 grants were issued for approximately 150 different types and brands of insulation products, including Zonolite® vermiculite insulation.[28] The actual number of homes which insulated using Zonolite® under the program is unknown, as CHIP was instituted prior to digital record-keeping. Existing paper records may contain information on a residence-by-residence basis on the products purchased under the grant to upgrade home insulation. These paper records may indicate potential exposure in homes that were insulated with Zonolite®, but would not reflect those that have since been remediated.

Indian and Northern Affairs Canada (INAC) has reviewed their records to attempt to identify where vermiculite insulation containing asbestos may have been used in the construction of houses on reserves.[29] Of houses built between 1960-1990, INAC found 597 references to houses that may have been built using Zonolite® Loose-Fill Vermiculite Insulation in the provinces of Saskatchewan (276), Manitoba (234), British Columbia (28), Quebec (28), and Alberta (5). An additional 6 references in the Yukon identified the use of vermiculite in general, but not specifically the Zonolite® brand. No records were available for the Northwest Territories of Nunavut, as housing is under the jurisdiction of Territorial Governments.

The Department of National Defence has assessed their complete housing portfolio.[27]

Health Canada has posted extensive information about vermiculite insulation that may contain asbestos on their website.[20]

NEXT: Occupational Exposures >>

Asbestos Occupational Exposures

Asbestos Occupational Exposures

Overview

Inhalation is the most important route of occupational exposure to asbestos.[1] CAREX Canada estimates that approximately 235,000 Canadians are exposed to asbestos in their workplace. Current asbestos-related disease is associated with exposures that occurred 10 to 40 years ago. This is due to the latency period between exposure and onset of disease. The exposure sources were very different at that time than they are now.

Prevalence Estimate

Using an approach that considered historical uses of exposure in Canada to guide exposure assessments for the present day, results indicate that approximately 235,000 Canadians are currently exposed to asbestos in their workplaces, and are primarily male (89%). This estimate includes people with the potential for exposure at work to any form of asbestos likely to exceed the non-occupational background level in dwellings or urban air (usually below 0.001 f/cm³).

The largest industrial groups exposed are construction-related (specialty trades and building construction contribute about 67% of all exposed workers). Other important industries include public administration, schools, and hospitals.

When examining exposure to asbestos by occupation, the largest exposed groups are carpenters (36,000 workers exposed), construction trades helpers and labourers (36,000 workers exposed), electricians (21,000 workers exposed), and janitors, caretakers and building superintendents (19,000 workers exposed).

The number of workers exposed to asbestos increased by approximately 83,000 workers from 2006 to 2016 (a 55% increase). This was primarily driven by the identification of additional occupations where exposure may occur, including in educational services, hospitals, nursing and residential care facilities, social assistance, and public administration industries.

Workers exposed to asbestos by industry in 2016

Workers exposed to asbestos by region in 2016

Click the second tab to view total number of workers exposed.

Level of Exposure

In total, approximately 235,000 Canadians are exposed to asbestos in their workplaces. The majority of workers exposed to asbestos are in the low and moderate exposure categories. A significant number of asbestos-exposed workers are at risk for high exposure.

Level of exposure by industry

Identifying industries with either 1) workers exposed to high levels of asbestos or 2) a larger number of workers exposed to asbestos is important in guiding cancer prevention efforts to prioritize exposed groups and target resources most effectively.

The table below shows the number of workers exposed by industry group and level of exposure to asbestos. These results highlight industries with the most number of workers, as well as industries with the highest levels of exposure. For example, in the specialty trade contractors and construction of building industries, a large number of workers are exposed, with many exposures occurring in the moderate and high exposure categories. Depending on the goals of a prevention campaign, exposure reduction in the large industrial group might be a useful strategy, or reducing exposure to those at highest risk of exposure could be seen as a priority.

Workers exposed to asbestos by exposure level and industry in 2016

*Numbers may not add up due to rounding

NEXT: Resources >>

Asbestos Resources

Package summaries

• Construction [PDF]
• Welder [PDF]
• Lung [PDF]

Fact sheets – Burden of Occupational Cancer

• Asbestos [PDF]
• Asbestos – Construction Industry [PDF]

Tools

• eWORK

Publications

• Peters CE, Palmer AL, Telfer J, Ge CB, Hall AL, Davies HW, Pahwa M, Demers PA. “Priority setting for occupational cancer prevention.” Saf Health Work. 2018;9(2):133-139.
• Peters CE, Ge CB, Hall AL, Davies HW, Demers PA. “CAREX Canada: an enhanced model for assessing occupational carcinogen exposure.” Occup Environ Med 2015;72(1):64-71.
• Setton E, Hystad P, Poplawski K, Cheasley R, Cervantes-Larios A, Keller CP, Demers PA. “Risk-based indicators of Canadians’ exposures to environmental carcinogens.” Environ Health 2013;12(1):15.

Videos

• CAREX Environmental Estimates Overview
• CAREX Occupational Estimates Overview
• CAREX eWORK Tool Overview

Other

• Priority lung carcinogens

Exposure Reduction

Our team has performed a detailed scan of exposure control resources and assembled a compilation of key publications and resources. These are organized by type of exposure (environmental or occupational) and by specificity (general or carcinogen-specific). Please visit our Exposure Reduction Resources page to view.

We also recommend exploring the Prevention Policies Directory, a freely-accessible online tool offering information on policies related to cancer and chronic disease prevention. Providing summaries of the policies and direct access to the policy documents, the Directory allows users to search by carcinogen, risk factor, jurisdiction, geographical location, and document type. For questions about this resource, please contact a member of the Prevention Team at the Canadian Partnership Against Cancer at [email protected].