IARC classifies carcinogens into several groups based on the strength of the evidence available:
Group 1: Carcinogenic to humans. Group 2A: Probably carcinogenic to humans. Group 2B: Possibly carcinogenic to humans. Group 3: Not classifiable as to its carcinogenicity to humans. Group 4: Probably not carcinogenic to humans.
These classifications are based on comprehensive reviews of existing scientific literature, including epidemiological studies, animal bioassays, and mechanistic data.
