The International Agency for Research on Cancer (IARC) announced on May 19, 2017, publication of Volume 111 of the IARC Monographs, Some Nanomaterials and Some Fibres. The Monograph contains evaluations of the carcinogenic hazard to humans of fluoro-edenite fibrous amphibole, silicon carbide fibers and whiskers, and carbon nanotubes. As reported in our November 3, 2014, blog item, a summary of the findings was published in The Lancet Oncology in 2014. The Working Group, which met September 30-October 7, 2014, classified fluoro-edenite fibrous amphibole as carcinogenic to humans (Group 1). Regarding silicon carbide fibers and whiskers, the Working Group classified occupational exposures associated with the Acheson process as carcinogenic to humans (Group 1), and fibrous silicon carbide as possibly carcinogenic to humans (Group 2B). Although not unanimous, the Working Group classified silicon carbide whiskers as probably carcinogenic to humans (Group 2A) rather than possibly carcinogenic to humans (Group 2B). The Working Group classified single-walled and multi-walled carbon nanotubes as not classifiable as to their carcinogenicity to humans (Group 3), with the exception of a specific multi-walled carbon nanotube. Multi-walled carbon nanotubes-7 were classified as possibly carcinogenic to humans (Group 2B).