printemailclick to share buttonfacebooktwitterlinkedin
Occupation and Environment

Increased research, surveillance and policy action are needed to increase our understanding of and to reduce workplace and environmental exposures to carcinogens.

There is convincing evidence that a number of products used in the workplace or in the environment are carcinogenic. However, there is limited high-quality, scientifically validated information about the contribution of carcinogens to cancer. Specifically, the relationship between cancer and many carcinogens at low levels of exposure is unclear.

Despite the limited scientific evidence, there is a high degree of public concern about occupational and environmental carcinogens and cancer, and a clear public health imperative to better understand and act on this risk factor.

Occupational Exposures

There is a larger body of evidence about occupational exposures and cancer than there is about environmental carcinogens, but it is still relatively limited. Preliminary estimates suggest that as many as 600,000 workers may be exposed to the most common workplace carcinogens, about half of these to solar radiation from working outdoors. About 70 men per year in Ontario will be diagnosed with mesothelioma, which largely results from previous occupational exposure to asbestos.

There has also been significant research done on the impact of radon exposures and cancer in workplaces that can be extrapolated for residential exposures. Other common workplace carcinogens include crystalline silica, diesel engine exhaust, wood dust, benzene, lead and compounds.

There is, however, no collected information in Ontario on the extent of occupational exposures to carcinogens and occupational cancer. The proportion of cancer cases attributable to exposures to carcinogens in the workplace is difficult to establish given, among other things, the long latency of cancer (i.e., the time between exposure to the cancer-causing agent and the diagnosis of cancer), and the potential involvement of many factors in the development of cancer.

There is a pressing need for a comprehensive surveillance strategy, tools and systems to measure exposure to occupational cancer-causing agents, as well as greater research to understand the problem and develop solutions.

In partnership with the Workplace Safety and Insurance Board, Cancer Care Ontario implemented a pilot project in June 2002: the Occupational Cancer Research and Surveillance Project. The project, which tracked the incidence of mesothelioma, a condition linked to asbestos exposure, by time and region in Ontario, was completed on December 31, 2005. The final report can be viewed here:

Environmental Exposures

Although it is unknown to what degree environmental carcinogens contribute to the burden, some studies have identified an increased cancer risk associated with exposure to environmental contaminants such as arsenic, radon, chromium and nitrates, and some substances found in the environment have been established as carcinogenic, e.g., radon, solar radiation, and environmental tobacco smoke.

Research and surveillance targeting the environmental substances that may trigger or promote cancer are required. Cancer Care Ontario scientists published a workshop report on environmental exposures, which outlines research, surveillance and prevention activities in this important sphere.

A recent Insight on Cancer, published by the Canadian Cancer Society and Cancer Care Ontario, reviewed the evidence for the association of cancer with particular environmental exposures, and discusses prevention and policy issues related to these exposures.

Cancer Care Ontario’s Plan Moving Forward

Working with the Ontario government and other stakeholders to better understand carcinogens and reduce cancer-causing exposures, Cancer Care Ontario launched the Occupational Cancer Research Centre in 2009. 

In 2008, Cancer Care Ontario and the Ontario Institute for Cancer Research initiated the Ontario Cancer Cohort, a long-term study of some 150,000 Ontarians to deepen our understanding of the causes of cancer, including occupational and environmental exposures.

Cancer and the Environment Stakeholder Group

From 2005–2007, Cancer Care Ontario convened a Cancer and the Environment Stakeholder Group. This group, which included stakeholders from health, professional and environmental organizations, charities and labour groups, was brought together to exchange knowledge, and to identify evidence-based priorities for the prevention of environmental carcinogen exposure, and opportunities for joint collaboration. The group also developed a list of environmental carcinogens for Ontario, and identified toxics use reduction as a complementary framework to the existing environmental carcinogen control system in Ontario.

Recently, the Ontario government introduced a strategy that includes toxic reduction legislation to reduce pollution, and inform the public and protect them from toxic substances in the air, water, land and consumer products.

In February 2007, CCO and the Canadian Cancer Society (Ontario Division) co-hosted an Environmental Carcinogen Use Reduction Symposium, which brought together stakeholders and experts from Ontario and other jurisdictions to review scientific evidence as well as national and international practices to prevent and control exposures to carcinogens. 

The symposium provided input into a report titled A Gap Analysis on Environmental Carcinogen Use Reduction. CCO provided technical and scientific advice to the report authors. The report sets out potential directions for future policy analysis and development.

Following are the background paper prepared for the first meeting of the Stakeholder group and proceedings from meetings.

Related Resources

Last modified: Mon, Nov 24, 2014
cancer care ontario | action cancer ontario   620 University Avenue Toronto Ontario, Canada M5G 2L7   Phone: 416.971.9800 Fax: 416.971.6888

Please help improve the quality of our website by answering 10 brief questions in our online survey. Would you like to participate?