Exposure to airborne asbestos associated with simulated cable installation above a suspended ceiling

Installing cable above a suspended ceiling in the presence of asbestos-containing fireproofing is an example of an activity that may disturb in-place asbestos and associated dust and debris. Two simulations of cable installation were conducted in a room of an unoccupied school to test the extent of such disturbance and resulting elevations in airborne asbestos. Average airborne asbestos concentrations in the room increased over 500-fold during the simulations, with several samples exceeding 50 structures per cubic centimeter (s/cm3), as measured by transmission electron microscopy (TEM) with an indirect preparation technique. Elevated concentrations persisted during a subsequent cleaning of horizontal surfaces in the room and for several hours thereafter. Personal samples collected on the cable installers yielded TEM measurements averaging approximately 68 s/cm3 for the two simulations.