Priority Carcinogens
Many occupational and environmental carcinogens are widely recognized because of the efforts of organizations such as the International Agency for Research on Cancer (IARC) and the U.S. National Toxicology Program. IARC, for example, has identified approximately 100 agents, groups of agents, mixtures or exposures as definite human carcinogens, another almost 70 as probable carcinogens and a further 240 as possibly carcinogenic to humans. Exposure to over half of these agents may occur in workplaces or communities in Canada, but there is limited data available on who is exposed to these agents and where and how they are exposed. Through occupational and environmental exposure surveillance, CAREX Canada will systematically gather data on Canadians’ exposure to carcinogens. This data is essential for:
- Setting priorities for policy or prevention-related activities.
- Monitoring trends in exposure.
- Identifying populations and geographic areas most affected.
- Setting research priorities.
- Providing information to policy makers.
- Educating the public.
Priority Carcinogens: Occupational & Environmental
Since approximately half of the “agents” (including chemical substances, radiation, biological agents, and exposure circumstances) categorized by the International Agency for Research on Cancer as possible, probable, and definite carcinogens have the potential for either occupational or environmental exposure, it is a huge undertaking to estimate exposures for all of them. To organize the task, a prioritization process has been undertaken.
After excluding agents with little or no potential for occupational or environmental exposure, substances were categorized into four priority groups: Immediate high priority; possible high priority; moderate priority with further substantial investigation warranted; and low priority with no evidence of use in Canada. The three criteria considered in this prioritization were:
- The carcinogenicity and other toxic properties of the substance.
- The prevalence of exposure in Canada.
- The feasibility of assessing exposure.
Two documents, one for environmental and one for occupational carcinogens, have been produced that summarize the categorization process used and identify the preliminary results of the prioritization.