A detailed evaluation of 122 air samples collected in and around Libby, Montana and previously analyzed by EPA has been performed. Photographic records of each analyzed particle were collected and archived in a searchable database. The results of the study indicate that the EPA’s failure to follow generally accepted procedures overestimated the concentration of regulated asbestos fibers by 10 times and by 3 times for all asbestiform fibers. These results are applicable to the analysis of naturally occurring asbestos in all parts of the country. The results demonstrate the need for detailed morphological and chemical analyses to reliably determine potential exposures and associated risks when evaluating mixed asbestos/non-asbestos environments.
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