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Asbestos Yarn

Asbestos in Yarn Products and Other Industrial Materials

Asbestos yarn is manufactured by breaking up raw asbestos material and twisting it into fibers that combine the flexibility of cotton and nylon yarn with the durability, strength and fire resistance of stone. Asbestos, despite its flexibility and fibrous appearance, is in fact a mineral. Combined with more conventional materials, asbestos creates a material that is almost (but not quite) indestructible. As such, it has found many uses in construction and industry. Asbestos yarn is used for packing pumps and bearings, sealing caulk and general insulation. It has also been used in safety clothing, such as fire suits and asbestos blankets.

Asbestos yarn is still manufactured in India, Mexico, China, Canada and Russia. Although most "new" uses of asbestos have been banned in the U.S., a number of these asbestos yarn products remain on the market and manage to make their way into the country in new construction. In addition, there are thought to be at least 750,000 buildings in the United States which still contain asbestos-based building materials of one form or another, including asbestos yarn. Older machinery, pumps, valves, etc., are also likely to contain asbestos yarn materials.

Recently, a study of former asbestos workers from Libby, Montana revealed that long-term exposure to chrysotile can also cause a number of auto-immune conditions, including multiple sclerosis and rheumatoid arthritis, in addition to the well-known hazards of asbestosis, lung cancer, and malignant mesothelioma.

Asbestos Yarn Products Containing Asbestos

The following partial list of asbestos yarn products were known to contain asbestos:

Product Name Start Year End Year
Amatex Asbestos Yarn 1950
H.K. Porter Yarn/Cord
John Crane Braid Over Braid Asbestos Yarn 915 1970
John Crane Commercial Grade Asbestos Yarn 9810 1970
Raymark Sealsafe (Yarn) 1972 1982
Raymark Yarn

Hazards Associated with Asbestos Yarn Products

When asbestos products are brand-new and freshly installed, they usually do not pose any specific health risk. Asbestos fibers must be inhaled or ingested to be dangerous to the human body. Unfortunately, despite asbestos’ noted durability and strength, when it is damaged by fire or impact, or when it simply becomes worn with age and use, the material becomes “friable.” This means that the material crumbles easily, especially when it is disturbed again. Ironically, some of the greatest danger from asbestos can come from efforts to remove old asbestos in buildings or machinery, as the now-friable material is even more damaged in the removal process.

Workers who maintained or repaired equipment or buildings where asbestos yarn was used, or who regularly handled cloth products made with asbestos yarn, are at a high risk of exposure to asbestos. Machinists, building engineers, engine repairmen, and demolition workers are at particular risk, although nearly anyone working in a mechanical or manual trade has the potential to be exposed to this dangerous fiber.



Bowker, Michael. Fatal Deception: The Untold Story of Asbestos (New York: Touchstone, 2003)

N/A. "Asbestos Linked to Autoimmune Diseases." Environmental Health Perspectives, vol. 113 (2004)

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