Asbestos is a group of six naturally occurring silicate minerals composed of thin, fibrous crystals. For most of the 20th century, asbestos was widely used in construction, manufacturing, and industrial products because of its fire resistance, durability, and insulating properties. However, when asbestos-containing materials are disturbed, microscopic fibers become airborne and, when inhaled or ingested, cause serious diseases including mesothelioma, lung cancer, and asbestosis.
The Six Types of Asbestos
Asbestos is divided into two mineral families. The serpentine family contains only chrysotile asbestos. The amphibole family contains five types: amosite, crocidolite, tremolite, anthophyllite, and actinolite.
- Chrysotile (white asbestos) — the most commonly used type, accounting for about 95% of commercial asbestos in the United States.
- Amosite (brown asbestos) — the second most common type. Used in insulation products, ceiling tiles, and cement sheets.
- Crocidolite (blue asbestos) — considered the most dangerous type.
- Tremolite — a contaminant in vermiculite (including the W.R. Grace mine in Libby, Montana) and some talc deposits.
- Anthophyllite — rarely used commercially; found as a contaminant.
- Actinolite — primarily a contaminant; limited commercial use.
Why Asbestos Causes Disease
Asbestos fibers are extremely small — thousands of times thinner than a human hair. When asbestos-containing materials are cut, sanded, broken, or degraded, these microscopic fibers become airborne and are inhaled or ingested. Once inside the body, the fibers are too durable for the immune system to break down or expel.
Over decades, embedded fibers cause chronic inflammation in the mesothelial tissue lining the lungs, abdomen, and other organs. This inflammation leads to DNA damage and eventually to cancer. There is no safe level of asbestos exposure — even brief contact can cause disease decades later.