WHMIS 1988 - Hazard-Specific Issues - Substances Assessed For Carcinogenicity


Substances that are known or appear likely to cause cancer are called carcinogens. These may include chemicals substances, infectious agents, radiation or radionucleotides. The tendency of these agents to cause cancer is called carcinogenicity.

WHMIS Classification and Hazard Communication

Section 54 of the Controlled Products Regulations (CPR) refers to specific "groupings" in the Threshold Limit Values (TLV) for Chemical Substances and Physical Agents and Biological Exposure Indices booklet published by the American Conference of Government Industrial Hygienists (ACGIH), and the International Agency for Research on Cancer (IARC) list of carcinogens. The substances included in these groupings are considered to be carcinogens under the CPR.

In 1987, the ACGIH modified Appendix A of their referenced publication to replace the A1a and A1b designations with the designation A1. At the same time, the listings of carcinogens were moved from Appendix A to the table of chemical substances with adopted TLVs.

The multi-stakeholder WHMIS committee through which policies employed in the administration of the program have been developed agreed that paragraph 54(a) of the CPR be revised to include categories A1, A2 and A3. However, as the proposed revision to paragraph 54(a) has not been published in the Canada Gazette Part II, inclusion in A3 would not constitute the sole criterion for classification as a controlled product in the absence of a regulatory amendment .

In general, if the referenced lists do not specifically address a chemical or group of chemicals, the results of the assessment described may or may not apply.However, consistent with section 33 of the CPR, where a product or a group of products was not specifically addressed in the referenced lists, the supplier or importer must still consider other evidence that carcinogenic (or other health) effects may result from exposure to the substance(s) and communicate those hazards on the product label and MSDS.

Designations - Explanatory Notes

American Conference of Governmental Industrial Hygienists

Confirmed human carcinogen
Suspected human carcinogen
Animal carcinogen. The agent is not likely to cause cancer in humans except under uncommon or unlikely routes or levels of exposure.
Not classifiable as a human carcinogen
Not suspected as a human carcinogen

International Agency for Research on Cancer

Group 1
The agent is carcinogenic to humans
Group 2A
The agent is probably carcinogenic to humans
Group 2B
The agent is possibly carcinogenic to humans
Group 3
The agent is unclassifiable as to carcinogenicity in humans
Group 4
The agent is probably not carcinogenic to humans


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