Table 2.

Proposed equivalences between the UN-GHS and IARC classification schemes

	Category 1A	Category 1B	Category 2	No classification
UN-GHS and CLP	Substances known to have carcinogenic potential for humans Largely based on human evidence	Substances presumed to have carcinogenic potential for humans Largely based on animal evidence	Substances suspected to have carcinogenic potential for humans Evidence obtained from human and/or animal studies but not sufficiently convincing to place the Substance in Category 1A or 1B	No sufficient evidence for classifying the substance as carcinogenic
	Group 1	Group 2A	Group 2B	Group 3	Group 4
IARC	The agent is a carcinogen for humans. This category is only used when sufficient indications of carcinogenicity for humans are available	The agent is probably carcinogenic for humans. The classification of an agent in this category is recommended if there is no formal evidence of carcinogenicity in humans, but corroborating indicators of its carcinogenicity for humans and sufficient evidence of carcinogenicity in experimental animals	The agent is possibly carcinogenic for humans. There is limited evidence of carcinogenicity in humans and evidence for animals, or insufficient evidence for human beings but sufficient evidence of carcinogenicity in experimental animals	Agent not classifiable as to its carcinogenicity to humans. (Insufficient evidence for human beings and insufficient or limited for animals)	Agent probably not carcinogenic for humans. (Evidence suggesting lack of carcinogenicity in humans and in experimental animals)