What is Vermiculite?

Vermiculite is a mineral that has numerous commercial applications. One of its properties is its tendency to expand when exposed to rapid increases in heat. Expanded vermiculite has been used as a component of insulation, concrete, potting soil and brake pad liners. Vermiculite from one major source, however, has been associated with asbestos and in some cases may pose a significant health risk.

History

Prior to 1990, nearly half of the world's production of vermiculite came from a mine in Libby, Montana. The mine became contaminated with asbestos and fibers that resembled asbestos. The U.S. Centers for Disease Control (CDC) indicates that although there is currently no evidence that vermiculite itself poses any health risk, the contaminated vermiculite fibers produced serious health problems for local miners and others who were exposed to them. The mine ceased production in 1990.

Horticultural Uses

Vermiculite has properties that make it an ideal soil additive for horticultural purposes. In its expanded form, the mineral improves soil aeration and provides excellent moisture retention. Horticultural vermiculite is sterile, non-toxic, odorless and permanent. It does not deteriorate, mold or rot and it typically maintains a neutral 7.0 pH level.

Commercial Uses

In addition to its horticultural and agricultural uses, vermiculite is used extensively by the commercial and home construction industries. The mineral is an important additive to everything from gypsum plaster to acoustic and soundproofing materials. It is used in insulation and for fireproofing as well as for packing, filtration, and absorption. It is added to cement, paint, sealants and dozens of other materials for countless industrial applications.

Geography

Vermiculite can be found in numerous countries throughout the world. Major commercial vermiculite mines are located in South Africa, China, Brazil, Zimbabwe and the United States. Until 1990 the most vermiculite was produced at the Libby, Montana mine, but currently most production comes from the Palabora region of South Africa and portions of China.

Warning

When handled, loose vermiculite can release finely divided particulate materials commonly referred to as nuisance dust. This nuisance dust is similar to that produced by other common materials such as sugar, cement and grain. When handling loose vermiculite, workers should wear respiratory protection to prevent symptoms of dust inhalation such as sneezing, coughing and lung irritation. Prolonged unprotected exposure to nuisance dust can compromise the lungs' ability to clear the dust from the respiratory system and make the lungs more susceptible to disease.

References

• Centers for Disease Control
• The Vermiculite Association
• The Vermiculite Institute

Resources

• Occupational Safety & Health Administration