Vermiculite is a naturally occurring mineral that has been widely used for over 80 years in the insulation, construction, horticulture and agriculture industries. Its appearance is similar to mica and it has a unique exfoliation property in which it expands to many times its original volume when heated. The most familiar form of vermiculite is the white particles that appear in potting soil. This substance is plentiful worldwide and is mined in almost every continent. The most productive mines are located in the Palabora region of South Africa, the northwestern corner of China and the eastern Appalachian Mountain Range of VA and SC.
Although asbestos does not naturally occur in vermiculite, some sources of vermiculite do contain a substantial portion of asbestos. Asbestos exposure creates a risk of mesothelioma or asbestosis. Specifically, vermiculite from the mines in Libby, MT contain tremolite asbestos. The Libby, MT mines were closed in 1990 due to the unhealthy hazards related to asbestos exposure. Almost all of the vermiculite mined today comes from deposits that are geologically older than those of Libby, MT.
Although a number of media sources have portrayed vermiculite negatively, including McCall’s Magazine, National Public Radio, Newsweek and 20/20, inspections have shown that the current processing and uses of this mineral is safe. For example, The Schundler Company was inspected by the EPA in 2000. Vermiculite was found to contain no asbestos during this inspection.
Any vermiculite that was mined and used in construction and insulation prior to the closing of the mines in Libby could conceivably contain asbestos. However, it is best if these materials are not disturbed, so they do not rustle up any asbestos dust that could be inhaled and eventually lead to malignant mesothelioma. In cases where vermiculite containing asbestos must be removed, the standard hazardous material handling protocols should be used. Therefore, before removing and destroying any construction materials, it is best to have them tested for asbestos.
For more on mesothelioma information click here.