In 1998, the National Institute for Occupational Safety and Health (NIOSH) revised the Criteria for a Recommended Standard: Occupational Noise Exposure [DHHS (NIOSH) Publication No. 98-126]. NIOSH reevaluated the recommended exposure limit (REL) for occupational noise exposure and reaffirms support for 85-dBA REL. Based upon scientific evidence, NIOSH recommends a 3-dB exchange rate. NIOSH recommends that significant threshold shift be identified as an increase of 15 dB in the hearing threshold level at 500, 1000, 2000, 3000, 4000, or 6000 Hz in either ear, with two consecutive audiometric tests. The new criterion has the advantages of a high identification rate and a low false-positive rate. In contrast with the former 1972 criterion, NIOSH no longer recommends age correction on individual audiograms. NIOSH has revisited its recommendations on the using of single-number laboratory-derived Noise Reduction Rating (NRR) required by the U.S. Environmental Protection Agency for labeling of hearing protectors sold within the United States. In 1972, NIOSH recommended the use of the full NRR value; however, the new criterion recommends derating the NRR by 25%, 50%, and 70% for earmuffs, formable earplugs, and all other earplugs, respectively. This presentation will compare and contrast current regulations against the NIOSH recommendations.
William J. Murphy, NIOSH Hearing Loss Prevention Team, 4676 Columbia Pkwy., MS C-27, Cincinnati, OH 45226-1998