The one percent dilemma
Decisions regarding the mitigation of hazards related to asbestos-containing materials are based on laboratory determinations that the bulk material contains greater or less than one percent asbestos. Therefore, it is imperative that laboratories provide accurate quantitative results for asbestos concentrations in bulk samples. This paper presents results of an evaluation of quantitation techniques available to laboratories, as well as laboratories' performance quantifying asbestos content of samples used in the proficiency testing portion of NIST's National Voluntary Accreditation Program. The findings of a recent U.S. EPA study involving low-percentage calibration standards are also examined.