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, three of which have been used for commercial applications:
- Chrysotile, or white asbestos, comes mainly from Canada, and has been widely used in the US. It is white-gray in color and found in serpentine rock.
- Amosite, or brown asbestos, comes from southern Africa.
- 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.
What are asbestos containing products?
What is common to many asbestos-containing products is that they were (are) used to contain heat (i.e. thermal insulation.) It is impossible to list all of the products that have, at one time or another, contained asbestos. Some of the more common asbestos-containing products are pipe-covering, insulating cement, insulating block, asbestos cloth, gaskets, packing materials, thermal seals, refractory and boiler insulation materials, transite board, asbestos cement pipe, fireproofing spray, joint compound, vinyl floor tile, ceiling tile, mastics, adhesives, coatings, acoustical textures, duct insulation for heating, ventilation and air conditioning (HVAC) systems, roofing products, insulated electrical wire and panels, and brake and clutch assemblies.
Samples of Building Materials that are composed of Asbestos fibers:
Some of these products contained a very high proportion of asbestos, while others contained small amounts.
Why is asbestos still a problem?
Asbestos is still a problem in the United States and elsewhere, because many asbestos-containing products remain in buildings, ships, industrial facilities and other environments where the fibers can become airborne, and because of the serious human health hazards of inhaling asbestos fibers.