Asbestos is the name for a group of naturally occurring silicate minerals that can be separated into fibers. The fibers are strong, durable, and resistant to heat and fire. They are also long, thin and flexible, so that they can even be woven into cloth.

Because of these qualities, asbestos has been used in thousands of consumer, industrial, maritime, automotive, scientific and building products. During the twentieth century, some 30 million tons of asbestos have been used in industrial sites, homes, schools, shipyards and commercial buildings in the United States.

There are several types of asbestos fibers, of which three have been used for commercial applications: (1) Chrysotile, or white asbestos, comes mainly from Canada, and has been very widely used in the US. It is white-gray in color and found in serpentine rock. (2) Amosite, or brown asbestos, comes from southern Africa. (3) Crocidolite, or blue asbestos, comes from southern Africa and Australia.

Amosite and crocidolite are called amphiboles. This term refers to the nature of their geologic formation.

Other asbestos fibers that have not been used commercially are tremolite, actinolite and anthophyllite, although they are sometimes contaminants in asbestos-containing products.