What is Asbestos and Asbestosis?


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:

  1. 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.
  2. Amosite, or brown asbestos, comes from southern Africa. (3) 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 do not have the adverse health consequences that result from exposure to commercial forms of asbestos.

How are people exposed to asbestos?

Exposure to asbestos occurs primarily through inhalation, though it can also be orally ingested. Substances such as automotive brake pads, floor tiles, wallboard material, fireproofing material, and thermal insulation products have been and continue to be manufactured with asbestos. Tiny asbestos fibers or bundles of fibers become dislodged from such products and become airborne. They can then be inhaled or can contaminate drinking water and be ingested. Federal agencies have determined that inhalation of asbestos is hazardous, but studies have yet to determine anything conclusive about other forms of exposure.

What are the effects of asbestos exposure?

Exposure to asbestos does not typically have acute effects. Rather, exposure over time may result in chronic diseases with long incubation periods. These include mesothelioma, cancer, and asbestosis.

Mesothelioma � There is also a very rare form of cancer called mesothelioma whose only known cause is asbestos exposure. This is the formation of malignant tumors in the linings of the internal organs or the body�s internal cavities. This disease will be discussed in more detail below.

Other Forms of Cancer � Because asbestos exposure occurs most frequently through inhalation, a very common effect is lung cancer. Many experts feel that cancer of the esophagus, stomach, or intestines can result from drinking water contaminated with asbestos, but this has not been proven. As much as thirty years can elapse between exposure to asbestos and the development of cancer (generally referred to as the �latency period�).

Asbestosis � Asbestosis is a type of lung disease that has traditionally afflicted naval shipyard workers. When asbestos fibers are inhaled, they can get caught in the lung tissue. Asbestosis starts when the body reacts to the foreign substance by producing an acid that is intended to destroy it. However, the acid frequently has little effect on the asbestos fibers and instead scars the tissues of the lungs. This can impair lung function, even to the point of lung failure and death. Symptoms include shortness of breath and persistent coughing. This disease can have a latency period of twenty-five to forty years.

Other effects of asbestos exposure can include pulmonary hypertension or immunological effects.

What-is-Asbestos-and-Asbestosis What is Asbestos and Asbestosis?

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.

Some of these products contained a very high proportion of asbestos, while others contained small amounts.


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