Breast Cancer Resources

The International Agency for Research on Cancer (IARC) classifies substances based on their carcinogenicity to humans. According to IARC, exposure to some substances or occupations may increase the risk of breast cancer.

There is limited evidence that the following occupational exposures may increase the risk of breast cancer:

• Ethylene oxide
• Polychlorinated biphenyls
• Shiftwork that involves circadian disruption

Who is exposed?

CAREX Canada estimates the number of Canadians exposed to carcinogens in the workplace. See the CAREX Canada carcinogen profiles for more information on exposures associated with breast cancer and the related industries and occupations:

• Ethylene oxide
• Polychlorinated biphenyls
• Shiftwork

What is the evidence?

See the IARC monographs for more information on the scientific evidence linking these substances or exposure circumstances with increased risk of bladder cancer:

• Ethylene oxide
• Polychlorinated biphenyls
• Shiftwork

For more information on how IARC classifies carcinogens, read this fact sheet.

OCRC Resources

• Research project: Exposures to emerging environmental contaminants and risk of breast cancer in young women
• OCRC shiftwork resources: Shiftwork in Canadian industries