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Occupational exposure

Occupational exposure occurs when a person is exposed to potentially harmful chemical, physical or biological substances at work. People who work with cancer-causing substances (carcinogens) on the job may be exposed to much higher levels of these substances than they would be at home or in their community. Since higher exposure can lead to greater cancer risk, eliminating or reducing exposure is important in the primary prevention of cancer.

Current scientific evidence suggests that being exposed to cancer-causing substances on the job is responsible for a small percentage of cancers. But for those workers, their exposure and risk of cancer is much higher than the average person’s.

  • Exposure and level of risk

    Occupational exposure is any contact between the human body and a potentially harmful substance that occurs in the workplace. The highest risk occurs when body surfaces, such as the skin, nasal passages and lungs, come in direct contact with the carcinogen. The cancer-causing substance may be absorbed or inhaled. Specific exposures are related to the type of work and the safety precautions taken to reduce exposure.

    Potential health risks may also be associated with how certain industries provide services or production. For example, researchers are studying the impact of shift work (working outside the normal workday, often at nighttime) and how it may be associated with cancer risk in workers.

    The level of risk depends on the amount and length of exposure, how powerful the carcinogen, the presence of other risk factors and a person’s susceptibility. Some workers may have greater and longer exposures to harmful chemicals in the workplace and their risk of cancer may be a lot higher.

  • Our position

    The Canadian Cancer Society strongly supports that Canadian workers should not be exposed to carcinogens in the workplace. Where exposure cannot be eliminated, it should be reduced to the lowest possible level. We also believe this will require the following commitments by employers, governments and individuals.

    Employers must:

    • educate workers about cancer and inform them about their exposure to carcinogens in the workplace 
    • eliminate or reduce exposure to carcinogens by removing them or by using a different substance 
    • establish processes and make changes to the workplace so that workers’ exposure to hazardous substances, including carcinogens, is minimized. The use of personal protective clothing or equipment should be a last resort
    • set up education and training programs for workers exposed to hazardous products in the workplace. Employers must also make sure that products are labelled, a Material Safety Data Sheet (MSDS) is present for each product and they are readily available to workers.

    Governments must develop evidence-informed legislation and regulations to protect workers.

    Individuals have the right (under provincial, territorial and federal health and safety legislation) to refuse work that exposes them to known and highly suspected carcinogens.

    What you can do

    If you’re concerned about exposure to a potential cancer-causing substance or would like more information about potential hazards in your workplace, contact the Canadian Centre for Occupational Health and Safety or the Canadian Cancer Society’s Cancer Information Service at 1-888-939-3333.

  • What workers can do

    Workers should do the following to help reduce their risk from occupational exposures:

    • Follow the employer’s occupational health and safety instructions when using, storing and disposing of hazardous materials.
    • Use all the protective clothing and equipment provided by the employer to help minimize the risk of exposure to potentially harmful substances.
    • Follow government and manufacturers guidelines for handling harmful substances.
      • Materials in the workplace have a Material Safety Data Sheet (MSDS). This document contains information on the potential hazards, health effects of exposure and how to work safely with the product. These guidelines are printed on the packaging and are posted in the workplace.
      • Canada’s Workplace Hazardous Materials Information System (WHMIS) identifies the hazards of a chemical and provides information on the safe use of hazardous materials. WHMIS information is provided through product labels, MSDS information and worker education programs.
    • Participate in training programs and use this information to work safely with hazardous materials. Tell employers when labels on containers have been accidentally removed or if the label is no longer readable.
    • Report accidental exposure immediately.

    Occupational research studies have given employers the knowledge to take actions aimed at reducing or preventing exposures to carcinogens in the workplace. Overall, the risk of exposure in the workplace today is much less than in the past because occupational health and safety practices have greatly reduced or eliminated exposure to cancer-causing materials.

  • Information about specific workplace exposures

    Canadian workers can be exposed to numerous substances or situations that have been shown to cause cancer or are suspected of causing cancer. Although studies have shown that some exposures increase a person’s risk of developing certain cancers, it may not be possible to conclusively link the cancer to a particular exposure.

    • Some workers may be more likely to come in contact with carcinogens. These include construction workers, woodworkers, miners, painters, pesticide workers and workers in the chemical, rubber or dye industries.
    • Arsenic, asbestos, benzene, beryllium, cadmium, chromium, ionizing radiation, nickel compounds, radon and vinyl chloride are examples of carcinogens that workers may be exposed to in the workplace.

    The Occupational Cancer Research Centre (OCRC) in Canada was established to increase information on the causes and prevention of occupation-related cancers. For more information, visit the OCRC website.

    The following pages have information on some specific exposures and how to protect yourself:

  • Suggested links for more information

    Reducing occupational exposures
    These organizations work to promote the health and safety of workers, which includes making sure they are protected from occupational exposure to carcinogenic substances.

    Canadian Centre for Occupational Health and Safety
    National Institute for Occupational Safety and Health, CDC
    Health Canada Occupational Health & Safety
    Health and Safety Executive (UK)
    World Health Organization – Global Plan of Action on Workers’ Health

    Information about workers’ rights in Canada
    Find out about your rights concerning health, safety and compensation for work-related injury and illness. 

    Association of Workers’ Compensation Boards of Canada
    Canadian Labour Congress 
    Canadian Labour Code – Section 125.1 outlines the duties of employers to protect employees from exposure to hazardous substances

    Research about occupational exposures
    These groups do research on occupational exposures and their impact on the cancer burden in Canada and internationally. 

    Occupational Cancer Research Centre 
    CAREX Canada 
    International Agency for Research on Cancer 
    National Toxicology Program (US)



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