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 were 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:
- 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.
- 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.
Other asbestos fibers that have not been used commercially are tremolite, actinolite and anthophyllite, although they are sometimes contaminants in asbestos-containing products. It should be noted that there are non-fibrous, or non-asbestiform, variants of tremolite, anthophylite and actinolite, which may not have the same adverse health consequences that result from exposure to commercial forms of asbestos.
Why is asbestos still a problem?
Asbestos is still a problem because a great deal of it has been used 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.
Many Americans believe that use of asbestos in products was banned years ago. The fact is that asbestos-containing products are still being imported and sold in this country, continuing to endanger people who may come in contact with such products. A majority of these products are imported from Canada and Mexico, two countries where asbestos is still used. Further, not all imported asbestos-containing products are clearly labeled with proper content information.