Regulated Asbestos Minerals: Tremolite and Actinolite
Libby, Montana: A dramatic example that asbestos exposure can cause serious disease and death.
Gold miners discovered vermiculite in Libby in 1881. In the 1920s, the Zonolite Company formed and began mining the vermiculite. In 1963, W.R. Grace bought the Zonolite mining operations. The mine closed in 1990.
While in operation, the Libby mine may have produced 80 percent of the world's supply of vermiculite. Vermiculite has been used in building insulation and as a soil conditioner. Zonolite was a product used for insulating homes, while another product, Monokote was used as blown on insulation in sky scrapers.
Unfortunately, the vermiculite from the Libby mine was contaminated with a toxic and highly friable form of asbestos called tremolite-actinolite series asbestos, often called Libby Amphibole asbestos (LA). EPA’s investigation determined LA to be present in air (indoor and outdoor ambient), vermiculite insulation and bulk materials, indoor dust, soil, water, animal and fish tissue and various other media. Because the local vermiculite contains asbestos, and the mine's byproducts were used in local buildings and landscaping, the town suffered from an extremely high rate of asbestosis. Nearly 10% of the population died from asbestos contamination, and the federal government later charged company officials for complicity.
In 1999, EPA responded to citizen, local government and media concerns regarding possible exposure to asbestos from the nearby vermiculite mine. EPA’s Removal program began conducting investigations and removal actions to address LA beginning in 2000. EPA placed the site on the Superfund program’s National Priorities List (NPL) in October 2002. In 2009, for the first time in the history of the agency, EPA declared a Public Health Emergency in Libby to provide federal health care assistance for victims of asbestos-related disease.
EPA has made significant progress in reducing the amount of LA in the area. This has reduced the chance of contact with LA, which is known to cause lung disease and other breathing problems. The amount of LA in air in downtown Libby is now nearly 100,000 times lower than when the vermiculite mine and mill were operating.
Investigation and cleanup of the site was completed in 2018 with the exception of the former vermiculite mine and forested areas (Operable Unit 3)
WR Grace vermiculite home insulation product "Zonolite" was shipped all around the US, including Hawaii.