IARC review of Category 1 carcinogens

In March, 2009, the International Agency for Research on Cancer (IARC) reassessed the carcinogenicity of metals, arsenic, dusts, and fibres previously classified as “carcinogenic to humans” (Group 1) and to identify additional tumour sites and mechanisms of carcinogenesis. Their findings are published in:

A review of human carcinogens—Part C: metals, arsenic, dusts, and fibres : The Lancet Oncology

Key points from this article include:

Metals

• The classification of beryllium and its compounds, cadmium and its compounds, chromium (VI) compounds, and nickel compounds as “carcinogenic to humans” (Group 1) was reaffirmed .
• Arsenic and inorganic arsenic compounds was classified as “carcinogenic to humans” (Group 1).

Asbestos

• Epidemiological evidence has increasingly shown an association of all forms of asbestos (chrysotile, crocidolite, amosite, tremolite, actinolite, and anthophyllite) with an increased risk of lung cancer and mesothelioma.
• Sufficient evidence is now available to show that asbestos also causes cancer of the larynx and of the ovary.
• The Working Group classified the evidence for an association between asbestos and colorectal cancer as “limited”.

Silica

• The Working Group reaffirmed the carcinogenicity of crystalline silica dust as Group 1. An increased risk of lung cancer was observed across various industries and processes.

Wood dust

• Wood dust was reaffirmed as “carcinogenic to humans”.
• Epidemiological studies report a strong association between exposure to wood dust and development of sinonasal cancer.
• There is strong evidence of carcinogenicity for hardwood dusts.
• For softwood dust there is a smaller riskthan for hardwood dust

Leather dust

• A particularly high risk of sinonasal adenocarcinoma was noted among workers with the highest exposure to leather dust.
• Leather dust was classified as “carcinogenic to humans” (Group 1).