NIOSH issues science policy recommending individual quantitative fit-testing for hearing protection, superseding prior derating guidance

NIOSH published an official science policy update recommending employers use individual, quantitative fit testing to evaluate the actual attenuation achieved by workers using hearing protection devices. The policy states it supersedes NIOSH’s earlier hearing protector derating guidance in the 1998 Criteria for a Recommended Standard—Occupational Noise Exposure. This guidance is relevant for occupational hearing conservation programs that previously relied on NRR-based derating assumptions and may drive updates to internal program practices (e.g., adoption of Personal Attenuation Rating (PAR)-based verification).