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Oregon State University

What is Asbestos?

Asbestos is the name applied to six naturally occurring minerals that are mined from the earth. The different types of asbestos are:

  • Amosite
  • Chrysotile
  • Tremolite
  • Actinolite
  • Anthophyllite
  • Crocidolite

Of these six, three are used more commonly. Chrysotile (white) is the most common, but it is not unusual to encounter Amosite (brown / off-white), or Crocidolite (blue) as well.

All types of asbestos tend to break into very tiny fibers. These individual fibers are so small that many must be identified using a microscope. In fact, some individual fibers may be up to 700 times smaller than a human hair. Because asbestos fibers are so small, once released into the air, they may stay suspended there for hours or even days.

Asbestos fibers are also virtually indestructible. They are resistant to chemicals and heat, and they are very stable in the environment. They do not evaporate into air or dissolve in water, and they are not broken down over time. Asbestos is probably the best insulator known to man. Because asbestos has so many useful properties, it has been used in over 3,000 different products.

Usually asbestos is mixed with other materials to actually form the products. Floor tiles, for example, may contain only a small percentage of asbestos. Depending on what the product is, the amount of asbestos in asbestos containing materials (ACM) may vary from 1%-100%.