Forgetting its fatal health hazards, asbestos fiber is an excellent material for insulation
Asbestos is a mineral that is made up of silicon, oxygen, hydrogen and other metal ions. Asbestos needle shaped fibers are so small that they cannot be seen unless the concentration in the air is very heavy.
Asbestos is an excellent material for insulation because the fibers are strong, flexible and will not burn.
The three most common forms of asbestos fibers are chrysolite, amosite and crocidolite.
Because asbestos is such a tiny fiber, it needs to be attached to something. When asbestos fibers are mixed with other materials, it produces what is called an asbestos containing material.
Courtesy of the EPA

Find out about the sources of asbestos exposure