Abstract
Asbestos-containing bulk samples which are routinely synthesized in the laboratory from known masses of readily available materials are part of an internal quality-control testing program. Quantitative analysis of asbestos in these samples by a laboratory's standard procedure yields precision and accuracy of that procedure. Permanent microscope-slide preparations of these samples are used specifically to assess polarized-light microscopic (PLM) analyses. Archives of these samples become references for field samples and allow determination of long-term precision and accuracy. The reliability of a two-step PLM method is determined by the above method.