The Libby Vermiculate Example

Most vermiculite used today contains low or non-detectable levels of asbestos. However, the vermiculite mined in Libby, Montana, from the turn of the 20th century to 1990 was contaminated with various fibrous amphiboles, including tremolite asbestos, and constituted 95% of the vermiculite used in the United States during that time.

The vermiculite operations in Libby, Montana, are a good example of the many ways people can be at risk to asbestos exposure. In this example, mining of the asbestos- contaminated vermiculite ore in Libby resulted in asbestos exposures to:

• Miners

• Household contacts of miners and other Libby asbestos workers

• Children playing in piles of vermiculite in the area

• Residents of nearby towns (where the air was contaminated by industrial activities involving asbestos)

• Workers who handled the vermiculite in vermiculite exfoliation and handling sites throughout the United States after it was shipped there from Libby

• People who live in homes with vermiculite home insulation

This vermiculite was also used in potting soil, but EPA concluded that consumers "face only a minimal health risk from occasionally using vermiculite products at home or in their gardens." (EPA 2000).

For more information about amphibole-contaminated vermiculite, see: An ATSDR map of 28 priority vermiculite exfoliating sites at http://www.atsdr.cdc.gov/asbestos/sites/national_map/.

An EPA fact sheet about how to recognize and avoid exposure to vermiculite insulation in homes at http://www.epa.gov/asbestos/pubs/insulation.html. An EPA fact sheet about how to avoid asbestos exposures while using potting soils at http://www.epa.gov/asbestos/pubs/vermfacts.pdf.