Vermiculite is a naturally occurring mineral used in the production of insulating materials. One of the most productive vermiculite mines was located in the Zonolite Mountains near Libby, Montana. The vermiculite ore from the Libby mines contained tremolite asbestos - extremely toxic and believed to be responsible for the unsually high number of asbestosis and mesothelioma deaths in and around Libby, Montana. Those afflicted include not only the miners and mill workers, but also their families and neighbors who were exposed to ore dust which contained the tremolite asbestos. Deadly ore dust invaded every aspect of life in Libby - air, water, clothing and food.
Much of the Libby vermiculite was used to produce Zonolite attic insulation, a product manufactured by Maryland-based W.R. Grace Company, the last owner/operator of the mines. The Libby mines were operated from approximately 1919 to 1990 when W.R. Grace halted mining operations. However, during seventy years of mining operations, the toxic vermiculite ore was shipped to over 50 processing plants throughout North America. In late 1999, the U.S Environmental Protection Agency launched an investigation of the Libby mines and surrounding communities. The investigation and related testing is expected to continue through mid-2000.
Exposure to asbestos can result in asbestosis and asbestos cancer, also known as mesothelioma, a rare and often deadly disease.