NIOSH Science Policy Update recommends individual quantitative fit-testing for hearing protection devices (Personal Attenuation Rating)

NIOSH issued a Science Policy Update (Publication 2025-104) recommending employers use individual, quantitative fit testing for hearing protection devices to determine a worker-specific Personal Attenuation Rating (PAR), rather than relying on derating of manufacturer Noise Reduction Ratings (NRR). This guidance affects hearing conservation program practices (fit-testing adoption, documentation, training, and procurement of fit-test systems) for organizations that align programs with NIOSH best practices.