Is asbestos a major threat to health? The U.S. Environmental Protection Agency (EPA) has convinced Congress to pass legislation requiring all schools in the United States to inspect for the presence of asbestos and, when present, to remove it.
Yet in the world community, asbestos is not considered a significant hazard. Rigorous studies in the United Kingdom, Sweden, Canada, and the United States testify to the relatively minor risk posed by asbestos. Complicating the issue is the grouping of several diverse minerals under the label asbestos: While all have similar properties that make them useful materials, they vary widely in health risk.
When the low risks of asbestos are balanced against its life-saving uses, one comes to realize that the legislation aimed at eliminating asbestos may create more problems than it proposes to solve. I consider the current asbestos policy and programs in the United States a huge scam. As an educator and scientist, I know the necessity of fully investigating any topic before drawing a conclusion, but regrettably, the EPA has not done so with asbestos.
Asbestos Minerals
There are two types of asbestos minerals: chrysotile asbestos and amphibole asbestos. Chrysotile is a hydrated magnesium silicate, one of the serpentine group of minerals commonly found in geologically altered, high-magnesium rock.
The amphibole group of minerals is extremely common in nature, but only a few varieties--crocidolite, amosite, tremolite, actinolite, anthophyllite--are asbestos-like. In nature, all amphiboles form elongated crystals and are fibrous to some extent. These amphibole asbestos minerals are all hydrous silicates that contain magnesium, as well as iron in some cases. Crocidolite contains some sodium, and tremolite and actinolite contain calcium.
Chrysotile accounts for more than 90 percent of the total asbestos used in the world, while crocidolite and amosite dominate the rest. Asbestos minerals have unique chemical and physical properties. The types with the greatest length-to-diameter ratio, chrysotile and crocidolite, are not only flexible but also have very high tensile strengths. All the asbestos minerals have excellent chemical and thermal stability; they are incombustible and acid-resistant. These properties make asbestos an excellent material for such things as fire retardants, brake linings, insulation, flooring and roofing materials, textiles, and packing materials. In many uses, including brake linings, there are no good substitutes for asbestos.
The fibrous nature of asbestos is, however, of concern to the health community. While the Occupational Safety and Health Administration (OSHA) defines a fiber as a particle of at least five microns in length, with a length-to-diameter ratio (L/D) of three or more, mineralogists argue that this description is too broad and that the term fiber should be restricted to material with L/D of at least 20. They point out that many minerals can, when crushed, yield fragments with L/D of three or more; certainly these are not all fibers.
Many health studies indicate some causative link between amphibole asbestos and illness. At the same time, no such correlation
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