Asbestos refers to a group of minerals that occur naturally as bundles of fibers. Because it resists heat and does not conduct electricity, it was used in many industries as insulation or fireproofing material; it can also be found in automotive brake shoes. When dust from this fiber is inhaled or swallowed, it can cause serious health problems, including lung cancer. People who become ill from it are usually exposed to it on a regular basis, most often in the workplace.
"Asbestos" is the name given to a group of minerals that occur naturally as bundles of fibers which can be separated into thin threads. These fibers are not affected by heat or chemicals and do not conduct electricity. For these reasons, asbestos has been widely used in many industries.
Four types of asbestos have been used commercially:
- Chrysotile (or white asbestos)
- Crocidolite (or blue asbestos)
- Amosite (usually has brown fibers)
- Anthophyllite (usually has gray fibers).
Chrysotile asbestos, with its curly fibers, is in the serpentine family of minerals. The other types (which all have rod-like fibers) are known as amphiboles.
Asbestos fiber masses tend to break easily into a dust composed of tiny particles that can float in the air and stick to clothes. The fibers may be easily inhaled or swallowed and can cause serious health problems, such as lung cancer.
Asbestos was mined and used commercially in North America beginning in the late 1800s. Its use increased greatly during World War II; since then, it has been used in many industries. For example:
- The building and construction industry has used asbestos for strengthening cement and plastics as well as for insulation, fireproofing, and sound absorption.
- The shipbuilding industry has used it to insulate boilers, steam pipes, and hot water pipes.
- The automotive industry uses it in vehicle brake shoes and clutch pads.
More than 5,000 products contain or have contained asbestos.
Government regulations and other actions, coupled with widespread public concern about the hazards of asbestos, have resulted in a significant annual decline in U.S. use of asbestos. Domestic consumption amounted to about 719,000 metric tons in 1973, but it had dropped to about 9,000 metric tons by 2002. Asbestos is currently used most frequently in gaskets and in roofing and friction products.