Further observations of settled asbestos dust in buildings

Surface sampling for asbestos is a tool used to determine the potential for asbestos exposure. It is also employed to estimate when a surface is sufficiently clean of asbestos structures. The sampling and analytical procedure employed has been described in ASTM standard method D 5755-95. Sampling was conducted in 66 buildings and from out-of-doors. The geometric mean surface concentration was 3.7 million asbestos structures per square centimeter (s/cm(2)) in areas with asbestos-containing fireproofing. Samples collected from areas having asbestos-containing acoustical plaster had a geometric mean of 160,000 s/cm(2). Samples collected in six buildings without friable asbestos-containing surfacing materials indicated a geometric mean of 1000 s/cm(2).