A Study of Beryllium Exposure Measurements, Part 2: Evaluation of the Components of Exposure in the Beryllium Processing Industry

Abstract

The characterization of exposure in the beryllium processing industry included collection of samples in the breathing zone during work near emission sources and the general area when employees performed other tasks. The amount of time an average employee spent at each task or area was determined. The arithmetic average exposure at each task was calculated and weighted by multiplying by the time spent performing the activity. These time-weighted results were added, and then divided by the total work time to estimate the daily weighted average (DWA). Each breathing zone and general area exposure measurement is identified by “BZ” or “GA” on the DWA calculation form. 643 individual DWA exposure values for workers with 38 job titles employed in the beryllium industry from 1972 to 1975 have been analyzed. Sixty-seven percent of mean breathing zone values exceeded 2 μg/m³, and 73 percent of the maximum exposures exceeded 2 μg/m³. In contrast, only 18 percent of the general area mean exposures exceeded 2 μg/m³. In general, breathing zone tasks were associated with shorter exposure times than general area sample tasks; for example, 83 percent of the breathing zone tasks and 42 percent of the general area tasks were of 30 minutes or less in duration. When task-specific data are available, cumulative exposure is only one of several exposure metrics which may be constructed (e.g., highest intensity, peak cumulative). This analysis of beryllium exposure data illustrates identification of several exposure excursions within the overall time-weighted exposure. These may be useful for construction of exposure metrics for occupational epidemiology studies and for targeting efforts to control exposure.