OSHA requires employers to make hearing protectors available to all employees exposed at or above 85 dBA TWA at no cost, to replace them as necessary, and to offer employees a selection from a variety of suitable types (29 CFR 1910.95(i)(1)-(3)). Proper initial fitting and supervised correct use are required (29 CFR 1910.95(i)(5)).
OSHA requires employers to make hearing protectors available to all employees exposed at or above 85 dBA TWA at no cost, to replace them as necessary, and to offer employees a selection from a variety of suitable types (29 CFR 1910.95(i)(1)-(3)). Proper initial fitting and supervised correct use are required (29 CFR 1910.95(i)(5)). HPDs must attenuate exposure to at least 90 dBA TWA — or to 85 dBA for employees who have already experienced an STS (29 CFR 1910.95(j)(2)-(3)). The manufacturer’s labeled NRR substantially overstates real-world attenuation. OSHA’s derating formula is (NRR – 7) / 2. NIOSH applies different derating factors by protector type: 75% of NRR for earmuffs, 50% for formable earplugs, and 30% for all other earplugs. Content must specify which method is being applied when citing attenuation estimates.
