On September 13, 2016, the Minnesota Department of Health (MDH) announced the availability of an updated list of chemicals of high concern.  Chemicals added to the list of chemicals of high concern include silicon carbide whiskers (Chemical Abstracts Service (CAS) Number 409-21-2), carbon nanotubes, multi-walled MWCNT-7 (CAS Number 308068-56-6), and silicon carbide, fibrous (CAS Number 308076-74-6).  MDH added these nanomaterials based on their International Agency for Research on Cancer (IARC) classifications.  As reported in our November 3, 2014, blog item, the IARC Working Group met on September 30-October 7, 2014, to review the carcinogenicity of fluoro-edenite, silicon carbide fibers and whiskers, and carbon nanotubes.  The Working Group classified carbon nanotubes, multi-walled MWCNT-7 as Group 2B (possibly carcinogenic to humans); carbon nanotubes, multi-walled, other than MWCNT-7 as Group 3 (not classifiable as to its carcinogenicity to humans); carbon nanotubes, single-walled as Group 3; silicon carbide, fibrous as Group 2B; silicon carbide whiskers as Group 2A (probably carcinogenic to humans); Acheson process, occupational exposure associated with as Group 1 (carcinogenic to humans); and fluoro-edenite fibrous amphibole as Group 1.  MDH reviewed chemicals classified as Group 1, 2A, or 2B for addition to the list of chemicals of high concern.[

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