What is Asbestos?
The term “asbestos” refers to a group of naturally occurring minerals with remarkable heat resistant qualities. There are six different types of asbestos, which are divided into two different groups: serpentine and amphibole. Some, but not all, of these asbestos types have been used commercially.
The serpentine group gets it name from the curved shape of the fibers. This group includes only one type of asbestos: chrysotile. Chrysotile was also commonly called white asbestos. Most of the chrysotile asbestos used in the United States was mined in Canada, Africa and the former USSR. Chrysotile was hugely popular with industry and accounts for more than 90 percent of the commercially used asbestos in the United States.
Amphibole asbestos fibers are straight, needle-like fibers. The amphibole group includes amosite (also called cummingtonite-grunerite or “brown asbestos”), crocidilite (also called riebeckite or “blue asbestos”), tremolite, anthophyllite and actinolite. Of these, only crocidilite and amosite were deliberately incorporated into commercial products. However, “noncommercial” amphibole fibers (tremolite, anthophyllite and actinolite) were sometimes present as contaminants in commercially used products containing chrysotile asbestos, vermiculite and talc. The amphiboles are commonly mined in southern Africa and Australia.
Asbestos is made up of microscopically small fibers, hundreds of times more fine than a human hair. If asbestos fibers are released into the air, they can remain airborne for extended periods of time. Sweeping or regular vacuuming can re-suspend the fibers, so small they slip right through a regular vacuum bag and escape back into the air. Asbestos fibers are too small to be seen or felt.
Source: Pathology of Asbestos-Related Diseases (Victor L. Roggli et al. eds., 2004).
Why Use Asbestos?
The term “asbestos” comes from a Greek word that means “unquenchable” or “indestructible,” and indeed it is almost impervious to the effects of heat, flame, salt water, chemical corrosion or biological processes. It is also flexible and strong (high tensile strength) and has low electrical conductivity.
Asbestos can be spun or woven for blankets that are fireproof, resist tears and provide good insulation. Asbestos fibers can also be mixed into products to make them stronger, more flexible and heat resistant.
Because of its many useful properties, asbestos has been referred to as the “magic mineral.” It has been incorporated into over 3,000 different industrial and household products.
