U.S. Fifth Circuit Court of Appeals remanded 1989 EPA asbestos ban in 1991

EPA banned most asbestos containing products in 1989 in response to public health concerns, but much of the rule was remanded by the U.S. Fifth Circuit Court of Appeals in 1991.

Current uses of asbestos include roofing products, gaskets, and friction products (brake linings, clutch facings).

Asbestos is the broad name given to a group of fibrous minerals that occur naturally in the environment. It is found in deposits or as contaminants in other minerals. The properties that make asbestos commercially viable are its high tensile strength, ability to be woven, heat resistance, and resistance to attack by acid or alkali.

Asbestos occurs in two mineralogical forms: serpentine and amphibole. Chrysotile belongs to the serpentine family, and is the most common asbestiform used commercially. Chrysotile fibers are curved and flexible. Amphiboles are rod or needle shaped and very brittle, and some evidence indicates that they may be more toxic than serpentine forms. The fibers found in Libby vermiculite belong to the amphibole family.

Legally, asbestos fibers are defined as particles with a length-to-width ratio of =3:1 and which are longer than 5 µm. Concentrations in air are reported as fibers per cubic centimeter; asbestos content in bulk materials is reported as a percentage. Asbestos can be detected in air or bulk materials using light and electron microscopy.

Courtesy of the Washington Department of Health