Asbestos is the name given to a group of six naturally occurring fibrous silicate minerals that have been widely used in commercial products. Asbestos is composed of silicate chains bonded with magnesium, iron, calcium, aluminum, and sodium or trace elements to form long, thin, separable fibers. These fibers are often arranged in parallel or matted masses.

Asbestos occurs naturally, but much of its presence in the environment stems from mining and commercial uses.

Asbestos fibers are classified by mineral structure as serpentine or amphibole.

Serpentine	Amphibole
Long, flexible fibers	Brittle with a rod or needle shape
Member: chrysotile	Members: crocidolite, amosite, anthophyllite, tremolite, actinolite, winchite, richterite
Accounts for 93% of world's commercial, purposeful use of asbestos	Accounts for 7% of commercial, purposeful use of asbestos

Asbestos was widely used commercially because of its

• high tensile strength
• resistance to acids and alkalis
• resistance to heat and flame
• flexibility.

These properties make asbestos commercially useful but also stable in the environment. Asbestos is nonbiodegradable. Once released to the environment, asbestos tends to persist.

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