IARC Classification

The IARC classification is a system used by the International Agency for Research on Cancer to rank how strongly the evidence shows that a substance causes cancer in humans. Substances are placed in groups ranging from Group 1, known human carcinogens, down to groups where evidence is limited or lacking. All forms of asbestos are classified as Group 1, the highest and most certain category.

Origin

IARC is the cancer research arm of the World Health Organization, founded in 1965 and based in Lyon, France. Its Monographs program, which produces these classifications, began in 1971, and asbestos was among the first agents it evaluated.

Significance in Asbestos Context

The Group 1 classification is one of the strongest pieces of general-causation evidence available in an asbestos case. It reflects the consensus of independent international experts, drawn from the published literature rather than from industry funding, that asbestos causes cancer in humans. Importantly, IARC classifies every commercial fiber type, including chrysotile, as a Group 1 human carcinogen, which undercuts the argument that so-called white asbestos is safe. Experts cite IARC to establish that asbestos can cause diseases like mesothelioma and lung cancer, before turning to the specific facts that connect a patient's own exposure to their diagnosis.

Example Sentence

The plaintiff's expert pointed to IARC's Group 1 classification of all asbestos types to rebut the defense claim that chrysotile in the brake products was harmless.

Related Terms

Group 1 Carcinogen, General Causation, Chrysotile, Mesothelioma, Weight of Evidence

Notes

• Ask your legal team whether the IARC monograph on asbestos is cited in the expert reports supporting general causation.
• Note that IARC rates strength of evidence, not dose; a Group 1 label does not by itself prove your individual exposure caused your disease.
• The classification covers all fiber types, which is useful when a defendant claims its chrysotile-only product was safe.