Appendix B: The IARC classification scheme Group Meaning Basis for classification Everyday examples (number of agents) Evidence from studies Evidence from animal studies 1 Carcinogenic Positive associations: chance, bias and confounding X-rays (116 agents as at can be ruled out. Diesel engine exhaust 2015) Alcoholic beverages Ultra-violet (UV) radiation UV tanning devices 2A Probably carcinogenic Positive associations for which a causal Causal relationship established in 2 or more PCBs (73 as at March 2015) interpretation is credible, but could also be due to species, or 2 or more independent studies in a Fumes from hot frying chance, bias or confounding. single species. 2B Possibly carcinogenic Either: Coffee (287 as at March 2015) Pickled vegetables (traditional in Asia) positive associations for which a causal The data suggests a carcinogenic effect but is too interpretation is credible, but could also be due to limited to make a definitive evaluation. Petrol engine exhaust chance, bias or confounding or has weaknesses that ELF magnetic fields mean no conclusions can be drawn RF fields or: have weaknesses that mean no conclusions can be Causal relationship established in 2 or more drawn. species, or 2 or more independent studies in a single species. 3 Not classifiable Have weaknesses that mean no conclusions can be Either the data suggests a carcinogenic effect but is Chlorinated drinking water (503 as at March 2015) drawn. too limited to make a definitive evaluation, or the Tea data has major quantitative or qualitative limitations. Static electric and magnetic fields ELF electric fields 4 Probably not Several studies, covering the range of human Caprolactam (chemical used in the carcinogenic exposures, which consistently show no increased production of Nylon-6, which is widely (1 as at March 2015) risk. Bias and confounding can be ruled out, and used in fibres and plastics) there is an adequate follow-up time. * This summarises the minimum requirements that must be satisfied in most cases, but there may be exceptions. For a full overview of the IARC process and classification scheme, refer to
Appendix B: The IARC classification scheme Group Meaning (number of agents) Basis for classification Everyday examples Evidence from studies Evidence from animal studies 1 Carcinogenic (116 agents as at 2015) Positive associations: chance, bias and confounding can be ruled out. X-rays Diesel engine exhaust Alcoholic beverages Ultra-violet (UV) radiation UV tanning devices 2A Probably carcinogenic (73 as at March 2015) Positive associations for which a causal interpretation is credible, but could also be due to chance, bias or confounding. Causal relationship established in 2 or more species, or 2 or more independent studies in a single species. PCBs Fumes from hot frying 2B Possibly carcinogenic (287 as at March 2015) Either: Coffee Pickled vegetables (traditional in Asia) Petrol engine exhaust ELF magnetic fields RF fields positive associations for which a causal interpretation is credible, but could also be due to chance, bias or confounding or has weaknesses that mean no conclusions can be drawn The data suggests a carcinogenic effect but is too limited to make a definitive evaluation. or: have weaknesses that mean no conclusions can be drawn. Causal relationship established in 2 or more species, or 2 or more independent studies in a single species. 3 Not classifiable (503 as at March 2015) Have weaknesses that mean no conclusions can be drawn. Either the data suggests a carcinogenic effect but is too limited to make a definitive evaluation, or the data has major quantitative or qualitative limitations. Chlorinated drinking water Tea Static electric and magnetic fields ELF electric fields 4 Probably not carcinogenic (1 as at March 2015) Several studies, covering the range of human exposures, which consistently show no increased risk. Bias and confounding can be ruled out, and there is an adequate follow-up time. Caprolactam (chemical used in the production of Nylon-6, which is widely used in fibres and plastics) * This summarises the minimum requirements that must be satisfied in most cases, but there may be exceptions. For a full overview of the IARC process and classification scheme, refer to
interagency-committee-on-health-effects-on-non-ionising-fields-may15.docx