The International Agency for Research on Cancer’s (IARC) Monograph Program evaluates substances, agents, and exposure circumstances on their carcinogenicity to humans. IARC recently released a summary of their evaluation of fluoro-edenite, silicon carbide fibres and whiskers, and carbon nanotubes.
Fluoro-edenite is a naturally occuring asbestos-like mineral. It was classified as carcinogenic to humans (Group 1) based on sufficient evidence in humans that exposure causes mesothelioma.
Silicon carbide exists as particles, fibres, or whiskers. Silicon carbide whiskers are used as substitutes for asbestos, and have similar dimensions to asbestos amphiboles. They were classified as probably carcinogenic to humans (Group 2A). Occupational exposure associated with the Acheson process, which forms silicon carbide fibres as a byproduct, was classified as carcinogenic to humans (Group 1), and causes lung cancer. Silicon carbide fibres were classified as possibly carcinogenic to humans (Group 2B).
Carbon nanotubes exist in many different lengths and diameters, and these different types may have different effects on human health. There is no human cancer data available, and the evaluation was based on animal studies and mechanistic data. One specific type of carbon nanotube, MWCNT-7, was classified as possibly carcinogenic to humans (Group 2B), while other carbon nanotubes were categorized as not classifiable (Group 3).
The summary of the findings is published in the Lancet Oncology and is available free of charge via their website. Click here to view the summary.