A newly published IARC monograph covers the findings from the Agency’s October 2014 meeting, which discussed the carcinogenic risks of fluoro-edenite, silicon carbide fibres and whiskers, and carbon nanotubes (CNTs) including single-walled (SWCNTs) and multi-walled (MWCNTs) types. The overall evaluations are summarised as follows:

Fluoro-edenite (fibrous amphibole) was classified as carcinogenic to humans (Group 1) based on sufficient evidence that exposure to fluoro-edenite causes mesothelioma in humans, as well as in laboratory animals.

Silicon carbide occurs in several forms, including particles, fibres and whiskers. Exposures associated with the most common manufacturing process of the silicon carbide particles (the Acheson process) were classified as carcinogenic to humans (Group 1), based on occupational cohort studies in which workers were exposed to fibrous and non-fibrous silicon carbide as well as quartz and cristobalite. IARC concluded that fibrous silicon carbide is possibly carcinogenic to humans (Group 2B) and silicon carbide whiskers are probably carcinogenic to humans (Group 2A).

Regarding CNTs, IARC concluded that SWCNTs and MWCNTs (excluding MWCNT-7) are not classifiable as to their carcinogenicity to humans (Group 3). MWCNT-7 has been shown to cause mesotheliomas in a number of animal studies, therefore there was sufficient evidence to classify this particular type of CNT as possibly carcinogenic to humans (Group 2B).

International Agency for Research on Cancer (2017). Some nanomaterials and some fibers. Volume 111. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. http://monographs.iarc.fr/ENG/Monographs/vol111/mono111.pdf

 

The above items were taken from the July 2017 issue of Toxicology and Regulatory News which is sent automatically to members of bibra.

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