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	vermiculite mineral samples scale compared with paperclip

Vermiculite has been an established commercial commodity for well over 50 years, and is currently used throughout the world. This unique mineral expands with application of heat in a process called exfoliation, yielding a light material suitable for use as loose fill insulation, packing material, etc. 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. Workplace exposure to the asbestos caused serious health problems in miners, millers and other processing workers, such as those who worked in exfoliation plants. Health problems from exposure have also occurred in the general Libby community. 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 investigators studied Libby vermiculite workers in the 1980s. They published important early research evaluating workers engaged in operations in and around the Libby vermiculite mine. This research documented significant excesses of asbestosis and lung cancer in the workers. These were related to exposures to the asbestos fibers that contaminate Libby vermiculite. In 2007, a NIOSH investigator published a follow up study confirming these findings. The paper is Sullivan, "Vermiculite, Respiratory Disease, and Asbestos Exposure in Libby, Montana: Update of a Cohort Mortality Study" (Environmental Health Perspectives, April 2007, ). Products containing vermiculite from Libby, Montana should always be presumed to be contaminated with asbestos and handled accordingly.


NIOSHTIC-2 is a searchable bibliographic database of occupational safety and health publications, documents, grant reports, and journal articles supported in whole or in part by NIOSH.

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
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 - 35 KB]
This December 2004 letter from NIOSH to OSHA describes NIOSH evaluations of potential asbestos exposures to downstream users of vermiculite.

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