Vermiculite

Vermiculite has been an established commercial commodity for well over 50 years, and is currently used throughout the world. Vermiculite ore mined near Libby, Montana, which accounted for more than half the worldwide production of vermiculite from 1925 to 1990, was contaminated with asbestos and asbestos-like fibers. Workplace exposure to these fibers caused a serious health problem in local miners and millers, as well as some downstream workers. Mining stopped at the mine near Libby in 1990. However, concerns remain about health effects from environmental and other occupational exposures to asbestos-contaminated vermiculite, especially vermiculite that has been installed as loose-fill insulation in homes and other buildings.

NIOSH is evaluating the potential for asbestos exposure during work with vermiculite from sources other than the mine near Libby. NIOSH is also updating a study of vermiculite workers originally conducted in the 1980s. That study found significant excesses of asbestosis and lung cancer related to contaminant fiber exposures among workers at the vermiculite operations in and around the mine near Libby. While information continues to be gathered, precautions should be taken to minimize the generation and inhalation of dust during the handling of vermiculite known or presumed to be contaminated by asbestos. As with any dust, workers should avoid prolonged high-level exposures.

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NIOSHTIC-2 search results on Vermiculite

NIOSH Publications

NIOSH Recommendations for Limiting Potential Exposures of Workers
to Asbestos Associated with Vermiculite from Libby, Montana
DHHS (NIOSH) Publication Number 2003-141 May 2002
PDF only 614 KB (2 pages)
Companion fact sheets provide information that employers and others can use to assess risks for Vermiculite exposure.

NIOSH Research in Libby, Montana: JOB-RELATED ASBESTOS EXPOSURES AND HEALTH EFFECTS IN MINING AND MILLING OF VERMICULITE
Companion fact sheets provide information that employers and others can use to assess risks for Vermiculite exposure.

Vermiculite Facilities Site Evaluations (HETA 2000-0407 Close-Out Letter)
PDF only 35 KB (3 pages)
This December 2004 letter from NIOSH to OSHA describes NIOSH evaluations of potential asbestos exposures to downstream users of vermiculite.

Related NIOSH Topics