IARC reevaluates silica and related substances.

An IARC working group of 19 experts in chemical carcinogenesis and seven industrial or governmental observers met in October 1996 in Lyon to prepare updated monographs and evaluations on crystalline and amorphous silica, palygorskite (attapulgite), sepiolite, and wollastonite. Monographs on these agents were published previously in Volume 42 of the IARC Monographs (1). Also evaluated by the group were some natural and synthetic zeolites (excluding erionite), coal dust, and the organic fibers paraaramid fibrils. Erionite, a fibrous component of some natural zeolite deposits in various parts of the world, was evaluated previously as being carcinogenic to humans (Group 1) in Volume 42 and Supplement 7 of the IARCMonographs (1,2).