Asbestos is a fibrous mineral that is chemically inert with heat resistant properties. It has been used in over 3,000 products, including fire proofing materials, cement, brake pads, plastics, paper products and textiles. There are two forms of Asbestos: Serpentine and Amphilbole. The Serpentine variety of asbestos is known as Chrysotile, while thee Amphibole variety includes Crocidolite, Amosite, Anthophyllite, Actinolite, and Tremolite.
Chrysotile, also known as white asbestos, accounts for ovr 90% of asbestos use because it is more flexible and has longer, thinner fibers than amphibole varieties. Amostie a brown asbestos, is typically used in insulating materials; Crocidolite, a blu asbestos, is typically used in asbestos-cement products; Temolite, a white-green asbestos, is used in laboratories for filtering chemicals; Anthophyllite, a gray-brown asbestos, is mined mainly in Finland and Actinolite, a dark green asbestos, has rarely been used commercially. Amphibole forms are distinguished from one another by color and by the amount of calcium, iron, magnesium and sodium contained within them. Amphibole forms of asbestos may pose a greater health risk than the Chrysotile forms of asbestos may pose a greater health risk than the Chrysotile forms of asbestos may pose a greater health risk than the echrysotile form because they are more rigid and less soluble, causing the eparticles to penentrate th lung tissue and remain within the tissue for a longer duration.
Vermiculite is an ore that can contain asbestos as a contaminant. It was first discovered in 1824 in Worchester, Massachusetts but was not mind commercially until 1923.
After mining and milling, the ore is heated to exfoliate or "pop" into a material that is fire resistant, chemically inert, absorbent, odorless and lightweight. Exfoliated vermiculite is used chiefly in agricultural and horticultural products. Other uses include insulation, construction material, and lightweight, absorbent packaging materials.
|Asbestos Fiber in Vermiculite|
Asbestos is a Greek word meaning "inextinguishable" or "indestructible". Greeks and Romans utilized it in lamp wicks, funeral dress and as napkins that could be cleaned by being thrown into a fire. The negative health effects to those working with asbestos were recorded by both the Greek geographer Strabo and the Roman naturalist Pliny the Elder. Asbestos was also used circa 2,000-3,000 BC in Egypt to wrap embalmed pharaohs and in Finland to strengthen clay pots. In the Middle Ages it was used as insulation in suits of armor. After visiting an asbestos mine in China in the late 13th century Marco Polo reported that asbestos was a stone, not the hair of a wooly lizard, as was previously believed. The modern asbestos industry began in 1880 when large Chrysotile deposits in Canada and the USSR were mined. The first modern applications included nonflammable fabrics, packing materials, high temperature equipment insulation, and cement products. It was not used extensively, however, until after World War II.
Typical asbestos mining in the United States consisted of open pit extraction followed by milling. Peak production of asbestos in the United States was over 299 million pounds/year in the late 1960s and early 1970s. Production decreased to 112 million pounds in 1987, 37 million pounds in 1989, 30 million pounds in 1993, 15.4 million pounds in 1997, and 13.2 million pounds in 1998 and 1999.
With the passage of the Safe Drinking Water Act in 1974 the Environmental Protection Agency set the Maximum Contami- nant Level (MCL) standard for asbestos at 7 million fibers per liter of water. The EPA issued a rule banning most asbestos products in July, 1989, but this regulation was overturned in 1991 by the New Orleans Fifth Circuit Court of Appeals. Corrugated, commercial and specialty paper; flooring felt and roll board remained banned after the regulation was overturned. The use of asbestos in products that did not historically contain asbestos is also prohibited. The following tables show land and water releases of asbestos by major U.S. industries as well as contemporary uses of asbestos.
EPA REGULATIONS AND FEDERAL LAWS GOVERNING ASBESTOS
The EPA regulations in Title 40 of the Code of Federal Regulations (CFR) can be accessed through the following link: http://www.epa.gov/docs/epacfr40/chapt-I.info/ index.html
Title 15 can be accessed through the United States Code Web site through the following link: http:// www.access.gpo.gov/uscode/title15/ chapter53_subchapterii_.html
Information regarding the health effects of asbestos can be found at the following sites:
- Asbestos Institute. Chrysotile Reference Guide (Available Online: http:// www.asbestos-institute.ca/crg/crgcontent.html#crg)
- United States Environmental Protection Agency Asbestos Home Page (Available Online: http://www.epa.gov/asbestos/ )
- United States Environmental Protection Agency EPA Asbestos Materials Bans: Clarification, May 18, 1999)
- General Electric Corporation. Wiring Materials Power Apparatus (Grand Rapids,Michigan: Jaqua Company, 1951)
- International Labor Office. Occupational Health and Safety, Vol. 1 (New York: McGraw-Hill Book Company, 1972)
- Montana Hardware Company. Catalogue No. A (Kaysville, UT: Inland Printing Company, 1940)
Historical Uses of Asbestos
Contemporary Uses of Asbestos
LINKS TO ASBESTOS INFORMATION