EPA memorandum on carpet asbestos testing, June 2002

NYC 9/11 Public Portal Document

APPENDIX A CHART FOR ESTIMATING AIR ASBESTOS LEVELS FROM DUST

Table A provides conversions from settled dusts to air levels using “K-factors.” This method is widely recognized, and used by EPA Region 1 in asbestos risk assessments.’’ It is used not only in the field of asbestos, but also for dusts containing other toxic substances such as lead, beryllium, uranium particles, alpha emitters, radioactive iodine, zinc sulfur powder, and microorganisms.’® It involves using experimentally determined ratios of levels in surface dusts to air levels, depending on the amount of human activity that would stir up the dusts.

The air test used by EPA, the AHERA TEM clearance test, is not sensitive enough to measure asbestos at the very low concentrations that can cause asbestos-related diseases such as lung cancer, mesothelioma, and asbestosis. As discussed earlier, the test is also not reproducible, giving highly erratic results, even in situations of high asbestos contamination on surfaces.

If there is settled asbestos dust, there is a potential for it to become airborne at hazardous levels, no matter what was measured in a one-time snapshot air test. Both carpets, upholstered furniture, drapes, and hard surfaces such as floors can be tested for settled asbestos dust levels, as described in the preceding memorandum.

Table A allows the user to choose from several different K-factors, depending on the amount of activity that would resuspend dusts. These K-factors were experimentally determined from real world situations. The situations involved actual buildings and rooms contaminated with asbestos, such as after the San Francisco earthquake. Researchers measured the levels of asbestos on the surfaces. Then, people outfitted with proper protective gear entered the areas to simulate different human activities. Air asbestos levels were then measured. Then, the ratio between the dust level and the air level was calculated, which is the “K-factor”.

The K-factors may be higher for WTC dust, because the asbestos is much more finely divided, and thus more likely to become airborne.

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