National Institute of Occupational Safety and Health, Current Strategies for Engineering Controls in Nanomaterial Production and Downstream Handling Processes… (2011)
“ Administrative controls and PPE are frequently used with existing processes where hazards cannot be effectively controlled solely with engineering controls. This could occur when control measures are not feasible or do not reduce exposures to an acceptable level. Administrative controls and PPE programs may be less expensive to establish but, over the long term, can be very costly to sustain. These methods for protecting workers have proven to be less effective than other measures and require significant efforts by the affected workers. ”
