According to the EPA website:
Asbestos is the name given to a number of naturally occurring, fibrous silicate minerals mined for their useful properties such as thermal insulation, chemical and thermal stability, and high tensile strength. Asbestos is commonly used as an acoustic insulator, thermal insulation, fire proofing and in other building materials. Many products are in use today that contain asbestos.
Asbestos is made up of microscopic bundles of fibers that may become airborne when asbestos-containing materials are damaged or disturbed. When these fibers get into the air they may be inhaled into the lungs, where they can cause significant health problems.
The National Directory of AHERA (Asbestos Hazard Emergency Response Act) Accredited Courses NDAAC directory is intended primarily for use by federal and state agencies. It contains information about training providers and approved courses nationwide and is meant to serve as a comprehensive reference and resource document. It may also be useful for those training providers who offer accredited asbestos courses and to all consumers of these training services.