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Vermiculite is a mineral that rapidly expands when heated. Expanded vermiculite is used in construction and consumer materials. Vermiculite 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 serious health problems to workers in the area and workers in the construction industry.

Concerns remain about health effects from environmental and other occupational exposures to asbestos-contaminated vermiculite. In the past, it was installed as loose-fill insulation in homes and other buildings.  Workers may be harmed from exposure to vermiculite. The level of exposure depends upon the dose, duration, and work being done.

NIOSH recommends that employers use Hierarchy of Controls to prevent injuries.  If you work in an industry that uses vermiculite, please read chemical labels and the accompanying Safety Data Sheets for hazard information. Visit NIOSH’s page on Managing Chemical Safety in the Workplace to learn more about controlling chemical workplace exposures.

The following resources provide information about occupational exposure to vermiculite products contaminated with asbestos.

NIOSH Chemical Resources

Related NIOSH Resources

  • NIOSHTIC-2 search results for vermiculite—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.
  • Asbestos/Vermiculite (Construction Renovation/Insulation)—NIOSH conducts research to prevent illnesses and injuries in the workplace. The NIOSH Worker Notification Program notifies workers and other stakeholders about the findings of these research studies.  

Selected Publications

Related Resources