PCBs upgraded by IARC to Group 1, known carcinogens
March 15, 2013 (Lyon, France) - In February 2013, 26 experts from 12 countries met at the International Agency for Research on Cancer (IARC), Lyon, France, to reassess the carcinogenicity of polychlorinated biphenyls (PCBs). PCBs are a class of aromatic chemicals that were historically used in Canada to manufacture electrical equipment, heat exchangers, hydraulic systems, and other specialized items.
On the basis of sufficient evidence of carcinogenicity in humans and experimental animals, the Working Group classified PCBs as carcinogenic to humans (Group 1). The classification is based on consistent association between PCB exposure and increased risk of melanoma in humans. There is also limited evidence from some studies suggesting that exposure is linked to increased risks of non-Hodgkin lymphoma and breast cancer. Additionally, dioxin-like PCBs were also classified in Group 1 on the basis of extensive evidence of a mechanism of carcinogenesis identical to that of 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD), and sufficient evidence of carcinogenicity in experimental animals.
According to Canadian legislation in 1980 and 1985, the only permissible use of PCBs is in older equipment, such as refrigerators, until the end of that equipment’s service life. The maximum allowable concentration of PCBs per equipment is 50 parts per million by weight. The equipment must have been designed to use PCBs at the time that it was imported, manufactured or knowingly offered for sale.
To learn more about PCBs and our estimates of Canadians' exposures to these chemicals in workplace and community environments, click here.
To view the Lancet Oncology article summarizing this reassessment, click here.