Noise Exposure Reduction: Hierarchy of Controls
The Occupational Safety and Health Administration (OSHA) requires us to follow this hierarchy of controls for all personal noise exposures. Ideally, we would isolate the noise source or install sound-absorbing materials to minimize the hazard. If this cannot be done, we implement administrative controls such as employee training (so personnel know how to void noises hazards) and employee rotation (so that each employee receives only a small amount of noise exposure and then the ear is allowed to rest). If these measures cannot minimize the level of noise to be <85 dBA, 8-hour time-weighted average, then the employee must be entered into the hearing loss prevention program (i.e., hearing conservation program) and earplugs or muffs must be used. Often these levels of controls are combined to minimize the noise as much as feasible, so any excess noise can be handled with rotation or Personal Protective Equipment (PPE). PPE is always the last resort because earplugs can be overlooked, improperly used, or damaged so that they are ineffective.
