Excessive exposure to dust among cleaners in the Ethiopian cement industry

Personal exposure to dust in cement factories occurs at all stages of the production process and is likely to vary between different stages of the process. Previous studies on cement production have focused on dust exposure among process operators and machine attendants. This study characterizes personal exposure to total and respirable dust among production workers in two cement factories in Ethiopia, with particular focus on cleaners. In Ethiopian cement plants, flow lines are partly open, and cleaning workers use brooms and shovels to remove dust that has settled on floors and machines. Personal full-shift samples of total (n = 150) and respirable dust (n = 36) were taken in the breathing zones of 105 cement workers. Samples of total and respirable dust were collected on 37-mm cellulose acetate filters of closed-face cassettes and in plastic respirable cyclones, respectively. In both factories, cleaners had significantly higher exposures to total and respirable dust than other production workers. Among cleaners, the geometric means for total and respirable dust exposure were 549 and 6.8 mg/m(3) in Factory A, and 153 and 2.8 mg/m(3) in Factory B. Temporal variability (within-worker) dominated the variability in the cleaners' total dust exposures. The distance from machines while performing cleaning tasks and the fraction of working hours spent on cleaning explained about 73% of the temporal variability in total dust exposure among cleaners. Only 7% of the production workers used respiratory protective devices. Preventive measures are needed to reduce dust exposure.