Impact of asbestos concentrations in floor tiles on exposure during removal.

This study investigated personal airborne exposure to asbestos during its abatement in two projects that had floor tile with different concentrations of asbestos. Abatement of floor tile with the higher percent asbestos exhibited the highest personal exposure level. Airborne exposure concentrations of asbestos between these abatement projects were found to be statistically significant. However, since neither had levels above occupational exposure standards this difference was not considered important, a type two error (false positive). It is suggested that when establishing negative exposure assessments, priority be given to process/work practices, with percent of contaminant in the building component being of less importance. Time period of applicability of data from negative exposure assessments to future projects should be considered indefinite. Neither within- or between-worker variation was predominant, in this study. Likelihood of exceeding occupational exposure standards during abatement of asbestos-containing floor tile, even for materials containing up to 15% asbestos, is low. Regulation of floor tile as a special category or group of asbestos-containing material appears to be warranted. Current schemes in the United States that regulate floor tile in the same group as other asbestos-containing materials would appear to be a legislating of science.