What is Asbestos?

Asbestos is the name given to several naturally occurring fibrous silicate minerals.  Asbestos can only be identified with a microscope.

It is still mined out of the earth in several countries.

  • Australia
  • Canada
  • South Africa
  • The former Soviet Union

Asbestos is known for its high tensile strength, thermal insulation properties, chemical and thermal stability.

The three most common types of asbestos are…

  • Chrysotile
  • Amosite
  • Crocidolite

environmental factors of cancerChrysotile, known as “white asbestos” is the most common.

The crystal development of Asbestos is what sets it apart from other minerals.  Its crystal formation is in the form of long thin fibers and it’s divided into two mineral groups…

  • Serpentine
  • Amphibole

Their crystalline structure is what separates the two groups.

Serpentine has a sheet or layered structure.  Amphibole has a chain-like structure.

Chrysotile is the only member of the serpentine group and is the most common type of asbestos found in buildings…90- to 95% of the asbestos found in buildings in the U.S. is Chrysotile.

I the Amphibole group we find five types.

  • Amosite (Brown Asbestos) This is the second most common type found in building material.
  • Crocidolite (Blue Asbestos) Used in special high temperature applications.
  • Anthorphyllite
  • Tremolite
  • Actinolite

The last three are rare and usually are found as contaminants in other minerals.

protective factors of cancer

What makes asbestos so hazardous?

Asbestos is made up entirely of microscopic bundles of fiber that readily become airborne when disturbed.  These microscopic fibers can hang in the air and become inhaled into the lungs where they irritate and can actually penetrate the sacs in the lung.  Significant health problems can result.

No one knows if there is a safe level of exposure.  What is known is that the greater and longer the exposure, the greater the risk of contracting an asbestos related disease.  the three most common asbestos-related diseases are:


  • This lung disease was first found among workers in navel shipyards.  The body tries to dissolve the fibers by producing an acid.  The fiber is very resistant to the chemical and little if any, the damage is done to the fiber.  But, the acid may scar the surrounding lung tissue.  This scarring progresses slowly and over a 25 to 40 year period can become so severe that the lungs no longer function.


  • Cancer of the outer lining of the lung and chest cavity (pleura) and the lining of the abdominal wall (peritoneum).  Asbestos is the only known form of this cancer and it’s cancer that you commonly hear about in connection with asbestos.  Symptoms often don’t show up for 15 to 30 years or more.

Lung Cancer

  • Lung cancer is generally associated with cigarette smoking but can also be caused by asbestos.  Asbestos and cigarette smoking combined can increase the effects of lung cancer by 50%  Cancer of the gastrointestinal tract can also be caused by asbestos.  Once again, symptoms may not appear for 15 to 30+ years.

When does asbestos become a hazard?

They are generally hazardous in the mining process and can be hazardous in the manufacturing process.

In building material and other products, it is generally not hazardous as long as it can be maintained in good condition.  It causes the biggest concerns when it’s removed or disturbed during remodeling or demolition.

When the material becomes damaged the fibers separate and can become airborne.  The industry used the term “friable”…this describes asbestos that can be reduced to dust (and become airborne) by hand pressure.

Another common term in the industry is “non-friable”.  This describes asbestos materials that are hard to reduce to dust with hand pressure.  Examples of this type of material are transite siding and floor tiles.  These materials are not, at this time, regulated.  Machine grinding, breaking, crushing, sanding, dry-buffing etc, are processes that can make them friable…their handling is then regulated.