Methods to lower the dust exposure of bag machine operators and bag stackers

This article reviews various dust control technologies developed over the years at the Pittsburgh Research Laboratory of the National Institute for Occupational Safety and Health (NIOSH) to provide various options and alternatives to lower bag machine operators' and bag stackers' dust exposures. Dust exposure records for the past 20 years show that bag machine operators and bag stackers normally have the highest respirable dust exposures of workers at mineral processing plants. A substantial amount of research has been performed over the years to minimize the dust exposure to these workers and the intent is to present all this information together in one article. Most of the research describes engineering controls that were adapted to existing facilities to reduce the dust generated during bag filling, bag conveying, and bag stacking. In some cases, a single technique succeeded in lowering respirable dust concentrations for all three processes, thus reducing the dust exposure to both the bag machine operator and the bag stacker. In other cases, a technique was developed to specifically reduce the dust exposure of one process or the other. This research also reviews various controls for secondary dust exposure, including general ventilation requirements to mill buildings, the effects of background dust sources, and personal work practices. This information is presented to help industrial hygienists, plant managers, engineers, and workers lower the dust exposure of bag machine operators and bag stackers.