In a major shift that modernizes workplace hearing protection guidance, the National Institute for Occupational Safety and Health (NIOSH) has released a new Science Policy Update recommending individual fit testing of hearing protectors.
This 2025 update builds on NIOSH’s 1998 Criteria for a Recommended Standard – Occupational Noise Exposure, which originally suggested fit testing but recognized that the necessary tools weren’t widely available at the time. Instead, NIOSH introduced a derating method to adjust the Noise Reduction Rating (NRR) for real-world use.
Now, with fit-test systems commercially available and a growing body of evidence showing that individual fit testing offers a more accurate estimate of protection, NIOSH is officially recommending it over NRR derating. This marks a significant step forward in ensuring workers are truly protected from harmful noise exposure.
As manufacturers and safety professionals look to align with the latest science, this policy underscores the importance of personalized protection and proper fit—because one size doesn’t fit all.
🔗 Read the full policy update (NIOSH Publication No. 2025-104)
ISEA continues to support advances in hearing protection technology, testing methods, and standards that help protect the hearing health of America’s workforce. Stay tuned as we work with our members to promote best practices in fit testing and noise hazard prevention.
