Analysis of asbestos in bulk materials -- 1980 to 1997
Federally sponsored asbestos proficiency testing programs have operated continuously in the United States since 1980. The U. S. Environmental Protection Agency published a test method for the analysis of asbestos in bulk materials in 1982, commonly referred to as the “Interim Method.” Major revisions were made to the method and the revised version was published in 1993. Polarized light microscopy, supplemented by x-ray diffraction, is the primary analytical technique presented in the 1982 and 1993 test methods. The 1993 version of the test method also recommends additional analytical techniques such as gravimetric sample reduction, transmission electron microscopy, and the use of bulk calibration standards. Research Triangle Institute's more than 17 years' experience evaluating the test methods and characterizing thousands of proficiency testing samples for testing programs indicates that the available analytical techniques can provide very accurate results for qualitative analysis of asbestos-containing materials and reasonably accurate results for quantitation of asbestos concentrations. The quality of the results being produced by the asbestos laboratory community appears to be most influenced by the skill level of the analysts and the degree of employment of the available analytical techniques.