Asbestos is a generic term used to describe hydrated magnesium silicate minerals that crystallize as bundles of long, thin fibers which readily separate when broken or crushed. These minerals include chrysotile (serpentine) and fibrous varieties of amphibole group minerals such as crocidolite, amosite, anthophyllite, tremolite, byssolite, and actinolite. The special properties of asbestos — high tensile strength, flexibility, and resistance to heat, chemicals, and electricity — have made it well suited for a number of commercial applications, particularly as fire-resistant tiles and insulation.
The first large-scale production in the U.S. began in 1894 at the Sall Mountain area of Georgia. Since then, asbestos has been mined in North Carolina, Virginia, Maryland, Pennsylvania, Connecticut, and Massachusetts, with at least sixty mines operating in the Eastern U.S. at various times. The Lowell quarry in north-central Vermont was the last asbestos mine to operate in the East, closing in 1993, and the last operation in the West closed in 2002. Asbestos is no longer mined in the United States.
Asbestos can be broken into tiny fibers, which can remain airborne for long periods of time. These fibers are exceptionally resistant to degradation and persist in the environment. Mounting evidence throughout the 20th century indicated that inhalation of asbestos fibers caused respiratory diseases, and many workers in asbestos-related occupations have been seriously affected. Exposure to asbestos has been linked to a number of serious health problems and diseases, particularly lung cancer. The most serious health risks are associated with asbestos concentrated in building materials that are disturbed during remodeling or demolition.
Asbestos minerals also occur naturally in rocks, saprolite, and soil. Naturally occurring asbestos that has been disturbed by human activities can be a health concern. Studies from California and Wyoming found that asbestos fibers released into the atmosphere from mining and quarrying posed a direct health threat to the nearby population.
Counties in Virginia that contain rocks with high levels of naturally occurring asbestos. Click on the map to see details about known asbestos locations in the Commonwealth.
In Virginia, asbestos minerals occur naturally, mostly in metamorphosed ultramafic rocks such as serpentine and soapstone in the Piedmont and Blue Ridge provinces. The U.S. Geological Survey Open File Report 2005–1189 provides information on twenty-eight asbestos sites in Virginia — nineteen reported occurrences, seven former prospects and two inactive production mines. The map to the right shows Virginia counties in which asbestos minerals are known to occur. These areas are considered potentially at risk, although the volume of atmospheric-borne asbestos minerals associated with these rocks is unknown.
The Virginia Department of Labor and Industry regulates asbestos as an indoor air contaminant, and the Virginia Department of Environmental Quality is responsible for the regulation of landfills in Virginia that dispose of asbestos materials, but no State agency is responsible for monitoring naturally occurring atmospheric-borne asbestos. The Fairfax County Health Department has developed an asbestos exposure control plan that is mandated for use in construction projects that excavate asbestos within the County.
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