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Context of 'November 18, 1999: Nearly 200 Deaths Attributed to Asbestos Problems'

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A study of the health effects of vermiculite mining, a mineral which is sometimes found with asbestos (as in the case of the vermiculite mine in Libby, Montana (see November 18, 1999)), finds that soils with an asbestos level of only 0.001 percent can result in air concentrations of 0.01 fibers per milliliter (f/mL), if disturbed. This exceeds the EPA cancer risk level of 0.000004 f/mL, the typical background levels of asbestos in outdoor air of 0.000002 f/mL, and the typical background levels in indoor air of 0.000003 f/mL (PCM). (Addison-Lynch 6/1995; Jenkins 3/11/2002 pdf file; Agency for Toxic Substances And Disease Registry 10/9/2003)

The Seattle Post-Intelligencer reports that at least 192 deaths and 375 incidents of fatal lung disease in Libby, Montana were caused by exposure to tremolite asbestos from a nearby vermiculite mine. The mine was operated by the company W.R. Grace Co. for 30 years until it was sold in 1990 to Kootenai Development Co. (Schneider 11/18/1999)

Three days after the Seattle Post-Intelligencer reported on asbestos contamination of homes in Libby, Montana (see November 18, 1999), the EPA dispatches an emergency response team to conduct tests to determine the level of asbestos contamination. For decades, local, state and federal agencies had ignored the known hazards at the Libby mine. (Schneider 2/2/2000; Schneider 9/15/2000) Twenty-three of the 73 outdoor air samples the EPA team will take at various locations in Libby are found to contain elevated levels of tremolite—a type of asbestos that is extremely carcinogenic due to its needle-like and sharply pointed fibers which easily penetrate the lining of the lungs. (Schneider 2/2/2000) Random air sampling inside the homes of Libby residents reveals that 11 to 23 percent of the selected homes have detectable levels of asbestos. The average level of asbestos inside Libby homes is found to be 0.0024 fibers per milliliter (f/mL), which exceeds many times the EPA cancer risk level of 0.000004 f/mL. (Jenkins 7/4/2003 pdf file)

The EPA posts a “questions and answers” page about asbestos and the EPA’s Libby investigation (see November 21, 1999) on its website. It includes only one question: “I recently read that EPA found less than 1 percent (or trace levels) asbestos at Fireman’s Park and other locations that were sampled. Is that a safe level?” The EPA responds that levels of “1 percent or less may be safe” under certain circumstances, but notes that it “could present a risk where there is enough activity to stir up soil and cause asbestos fibers to become airborne” (see 1995). (Environmental Protection Agency 6/18/2001)

The EPA begins removing asbestos from private homes in Libby, Montana where a nearby mining operation contaminated the surrounding area (see November 21, 1999). The EPA conducts the cleanup operation under the authority of the National Contingency Plan (NCP) (see 1972). (Jenkins 12/3/2001 pdf file; Jenkins 1/11/2002 pdf file; Kupferman 2003 pdf file; Environmental Protection Agency 7/26/2004) In some cases, it will be necessary for the EPA to take extreme measures to ensure that asbestos levels in certain homes meet EPA standards. For example, the agency will have to completely demolish one home and rebuild it after the standard procedures of replacing carpets, upholstered furniture, and professional abatement fail to reduce the presence of asbestos to an acceptable level. (Jenkins 7/4/2003 pdf file)

EPA Region 2 decides that it will use a benchmark of 1 percent in determining whether the asbestos level found in outdoor dust samples collected in and around the WTC site constitutes a “level of concern.” The figure apparently derives from the National Emission Standards for Hazardous Air Pollutants (NESHAP) (see April 18, 1989), which defines products containing more than 1 percent asbestos by weight as “asbestos-containing materials” (ACM). The NESHAP one percent definition is not based on safety, but rather is the detection limit of the Polarized Light Method (PLM) for determining asbestos levels (see August 23, 1996 and see November 20, 1990). The EPA will be heavily criticized for selecting this percentage as its “level of concern” benchmark. Critics will argue:
bullet The one percent value is arbitrary because it is not based on safety. Furthermore, it was meant to be applied only to solid asbestos-containing products that do not release emissions (like dust).
bullet As the EPA has previously acknowledged, there is no safe exposure level to asbestos (see April 25, 1986) (see April 18, 1989).
bullet Measuring dust by percentage weight does not allow one to accurately assess the risk to public health because it does not determine the number of asbestos structures in a given area. For example, a sidewalk coated with 4 inches of dust containing .5 percent asbestos is much more of a health risk than a tablespoon’s worth of dust on the ground containing 2 percent asbestos because the former obviously has many more structures of asbestos. A person walking on the street would inhale more asbestos fibers walking through the 4 inches of asbestos-contaminated dust than stepping on just the tablespoon’s worth. (Jenkins 6/9/2002 pdf file) In fact, the EPA has previously acknowledged in an official statement to the public that levels “of 1 percent or less could present a risk where there is enough activity to stir up soil and cause asbestos fibers to become airborne” (see June 18, 2001). Additionally, a study in 1995 on the health effects of vermiculite found that soils with an asbestos level of only 0.001 percent can result in air concentrations of 0.01 fibers per milliliter, which exceeds many times the EPA cancer risk level of 0.000004 f/mL (see 1995) that corresponds to a cancer risk factor of 10

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