IARC group 2B substances, mixtures and exposure circumstances are those that have been classified as "possibly carcinogenic to humans" by the International Agency for Research on Cancer (IARC) as [1] This category is used when there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. It may also be used when there is insufficient evidence of carcinogenicity in humans but sufficient evidence in experimental animals. In some cases, an agent, mixture, or exposure circumstance with inadequate evidence of carcinogenicity in humans but limited evidence in experimental animals, combined with supporting evidence from other relevant data, may be included in this group.
This list focuses on the hazard linked to the agents. This means that the carcinogenic agents are capable of causing cancer, but this does not take their risk into account, which is the probability of causing a cancer given the level of exposure to this carcinogenic agent.[2] The list is up to date as of January 2024.[3]
A cancer hazard is an agent that is capable of causing cancer, whereas a cancer risk is an estimate of the probability that cancer will occur given some level of exposure to a cancer hazard.
