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Health hazard evaluation report: measurement of exposure to impulsive noise at indoor and outdoor firing ranges during tactical training exercises.

Brueck-SE; Kardous-CA; Oza-A; Murphy-WJ
Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, HETA 2013-0124-3208, 2014 Jun; :1-25
The Health Hazard Evaluation Program received a request from a federal agency concerned about firearms instructors' exposures to high intensity impulsive noise from weapons firing. The weapons were used during employee tactical training and firearms qualification exercises at indoor and outdoor firing ranges. The agency wanted to know about peak sound pressure levels, B-duration of the impulse noise waveform, and how much weapons fire instructors could be exposed to per day. To address concerns, we (1) measured instructors' exposures when training with several firearms and weapons systems, and (2) calculated the number of gunfire exposures permitted per day without incurring a significant risk of hearing loss. We used the NIOSH impulsive-noise measurement system to calculate potential risk to hearing based on three criterion: (1) the United States Department of Defense MIL-STD-1474D, (2) the A-weighted 8-hour equivalent sound level equal energy criterion (LeqA8hr), and (3) the Auditory Hazard Assessment Algorithms for Humans (AHAAH). We determined that during most training exercises, instructors were exposed to peak sound pressure levels greater than 150 decibels, greater than the NIOSH-recommended ceiling limit of 140 decibels. Peak sound pressure levels for the Dillon M134D minigun, 12-gauge shotgun, and full load flashbang grenade were sometimes greater than 170 decibels. Instructors could exceed the number of gunfire exposures permitted per day. Although most instructors wore ear plugs and ear muffs, we saw single hearing protection used at outdoor ranges; not all hearing protectors appeared to be deeply inserted into the hearing canal. We recommended the employer (1) install noise controls at the outdoor and indoor ranges, (2) use noise suppressors on firearms, if feasible, (3) use the most protective criterion to limit the number of daily gunfire exposures, (4) require use of dual hearing protection during all live fire training exercises, and (5) fit test employees for the hearing protection they use. We recommended the instructors wear dual hearing protection during all live fire training exercises.
Region-4; Noise; Noise-levels; Noise-exposure; Impulse-noise; Training; Noise-induced-hearing-loss; Hearing-impairment; Hearing-conservation; Hearing-disorders; Hearing-loss; Auditory-system; Personal-protection; Personal-protective-equipment; Protective-equipment; Noise-protection; Author Keywords: National Security; noise; impulse noise; impulsive noise; peak noise; damage risk criteria; firearms; weapons; guns; gunfire; hearing loss
Publication Date
Document Type
Field Studies; Hazard Evaluation and Technical Assistance
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
HETA-2013-0124-3208; M072014
NIOSH Division
Priority Area
Services; Construction; Manufacturing
SIC Code
Source Name
National Institute for Occupational Safety and Health