A meta-analysis of airborne asbestos fiber concentrations from work with or around asbestos-containing floor tile

In this meta-analysis, exposures to airborne asbestos during work with or around floor tiles were characterized according to several variables: study, sample type, activity, and task. Personal breathing zone, bystander, and area sample exposure concentrations were differentiated and compared against current occupational exposure limits to asbestos. In total, 22 studies, including 804 personal, 57 bystander, and 295 area samples, were included in the analysis. The arithmetic mean airborne fiber concentrations were 0.05, 0.02, and 0.01 f/cm(3) for personal, bystander, and area samples, respectively. Arithmetic mean time-weighted-average fiber concentrations over an 8-h working day were 0.02 and 0.01 f/cm(3) for personal and bystander samples, respectively. Phase contrast microscopy (PCM) personal airborne fiber concentrations were highest for maintenance activities, followed by removal and installation. Tasks that involved buffing or burnishing, scoring or snapping, and scraping or lifting had the highest personal PCM concentrations, while stripping floor tile and removing it with chemical solvent had the lowest concentrations. Exposures associated with handling asbestos floor tiles, under working conditions normally encountered, do not generally produce airborne concentrations at levels that exceed the current OSHA PEL nor do they appear to approach the threshold cumulative asbestos dose concentrations that have been previously associated with an increased risk of asbestos-related disease.