Asbestos

From ArticleWorld

Asbestos is a type of silica-like fibrous mineral that has become useful in many industrial areas due to its resistance to fire. It consists of many small fibers that can actually be woven into a cloth or mixed with other materials like cement. Many of its uses are now banned due to its resulting in respiratory diseases and a specific type of lung cancer. Asbestos particles are so thin—thinner than a human hair—and can easily be inhaled into the lungs.

Historical uses

In ancient history, asbestos was used in Egyptian burial cloths and other types of mats. It is part of molded brake shoes and gaskets because of its heat resistance. Historically, asbestos products were used in electric oven wiring because it was a good electrical insulator. It was also used as a thermal insulator for high-temperature electric conductors and in insulation in many commercial buildings. Asbestos was also used to make perpetual wicks that burned in oil lamps but did not become consumed by the fire.

Types

Serpentine rocks or “serpentine asbestos” is made from curled fibers of asbestos. Amphibole asbestos comes is contains straight, needle-like asbestos fibers. White asbestos is a serpentine-type of asbestos that is obtained from Canadian serpentine rocks. It is not so stiff and is less likely to be inhaled. It is believed to be less harmful than other types of asbestos.

Asmosite or “brown asbestos” comes from Africa and is of the amphibole variety. Along with blue asbestos or “Crocidolite”, mined in Africa and Australia, brown asbestos contains straight fibers which are more dangerous than the serpentine fibers. Blue asbestos is believed to be the most dangerous type of asbestos.

There are other asbestos-based minerals that are still found in construction materials, including insulation. Vermiculite and talcum powders sometimes contain these types of asbestos. The U.S. Environmental Protection Agency has banned the use of any construction product containing more than 1% asbestos, including the safer, more friable asbestos fibers. All products containing the amphibole group of asbestos products have been banned since the mid 1980s.

Diseases from asbestos

The primary problem with asbestos is that of asbestos-related lung disease which has been suspected since before 1900. Asbestos is the primary cause of mesothelioma, a form of lung and abdominal disease that affects the lining around these cavities. The term “asbestosis” is used to describe a type of lung fibrosis common in those regularly exposed to the fibers. Inhaling the needle-like structures cause an inflammation in the lungs and secondary scarring or fibrosis, which can be fatal.

Asbestos can get under the skin and cause “asbestos warts”. Overall thickening of the lining of the lungs or plaques of fibrous material can be seen on the chest X-rays of those that have been extensively exposed to these fibers.