Asbestos

Asbestos refers to a set of six naturally occurring fibrous minerals. Asbestos has six primary sub-classifications. These are chrysotile, crocidolite, amosite, anthophyllite, tremolite, and actinolite. Among these, chrysotile and amosite asbestos are the most common.

Asbestos fibers are microscopic but extremely durable and resistant to fire and most chemical reaction and breakdown. For this reason, asbestos was used for many years in a number of different commercial and industrial capacities. Because of its strength and resistance to heat, asbestos was used in roofing shingles, floor tiles, ceiling materials, cement compounds, textile products, and automotive parts. Asbestos is now strictly regulated as asbestos exposure is now associated with a number of lung and respiratory health conditions.

Asbestos use was discontinued in the late 1970s upon being found to be a hazard to human health. Today, asbestos is classified as a known human carcinogen. The durability properties, which made asbestos so desirable to manufacturers, are that which make asbestos hazardous. Because asbestos fibers are microscopic (roughly .02 the diameter of a human hair) they are easily inhaled. Once inhaled, the fibers cling to the respiratory system, including the lining of the lungs and inner cavity tissue. As asbestos fibers are typically quite rigid, they lodge easily in the soft internal tissue of the respiratory system and are not easily expelled or broken-down by the body.

Because asbestos use was so prominent until it’s hazards became clear in the late 1970s, hundreds of thousands of people were exposed to the mineral in some capacity. There is no safe type of asbestos and no safe level of exposure. Nearly all those with exposure history are potentially at risk of serious respiratory health complications.

There were hundreds of occupations affected by asbestos exposure. Asbestos was used in thousands of commercial products and industrial capacities and those working with the material in these industries are potentially at risk of harmful exposure. Industries in which asbestos use was particularly prevalent include shipbuilding, commercial product manufacturing, power plants, and construction. Workers employed in these industries prior to 1980 likely encountered asbestos products.

While asbestos exposure is hazardous, not all asbestos products are inherently hazardous. Because asbestos must be inhaled to represent a health risk, only loose asbestos fibers or those in the air supply (a condition known as friable) represent a true hazard. Stable asbestos compounds, such as intact cement, tiles, or other products are generally not an immediate hazard.

Exposure to friable asbestos fibers was common when grinding, chipping, demolishing, or retrofitting asbestos products. Each of these functions could potentially release asbestos into the air supply where it would be easily inhaled.

There are three major lung conditions traced directly to asbestos exposure. These are lung cancer, mesothelioma, and asbestosis. Lung cancer risk, typically associated with tobacco use, is known to be exacerbated by exposure to asbestos. Symptoms include coughing, chest pain, and difficulty breathing.

Asbestosis is a degenerative and progressive non-malignant long-term respiratory condition. Asbestosis results from the formation of scar tissue plaques on the visceral surface of the pleura. Asbestosis can represent a pre-cursor to the onset of mesothelioma.

Sources :
Environmental Protection Agency. Asbestos: Basic Information
http://www.epa.gov/asbestos/pubs/help.html
 

American Cancer Society. Mesothelioma: Questions and Answers
http://www.cancer.gov/cancertopics/factsheet/Sites-Types/mesothelioma

The Mayo Clinic: Asbestosis
http://www.mayoclinic.com/health/asbestosis/DS00482