Asbestos refers to a set of six naturally occurring fibrous minerals: chrysotile, crocidolite, amosite, anthophyllite, tremolite, and actinolite. Among these,chrysotile and amosite asbestos are most common. These fibers are found naturally in soil and rocks in many parts of the world and consist of mainly silicon and oxygen but also contain other elements as well.
Asbestos fibers are microscopic—roughly 2% the diameter of a human hair—and therefore 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 become lodged in the soft internal tissue of the respiratory system and are not easily expelled or broken down by the body.