During most training exercises at a federal firearms training complex, NIOSH found instructors exposed to peak sound pressure levels above 150 dB, more than 10 dB over the 140 dB ceiling that both OSHA and NIOSH apply to impulse noise (NIOSH Health Hazard Evaluation 2013-0124-3208, 2014). A single earplug or earmuff removes only 25 to 35 dB of that peak (Murphy and Tubbs, Journal of Occupational and Environmental Hygiene 2007). NIOSH estimates that 40,000 to 60,000 people work at US shooting ranges (NIOSH Publication 2013-104), and a separate US Marine Corps study found that weapons instructors without an active earmuff ended one year with high-frequency hearing 3 dB worse than those who had one (Federman et al., Annals of Work Exposures and Health 2022). We aggregated data from NIOSH Health Hazard Evaluations, the US Army Public Health Center, OSHA, peer-reviewed audiology and occupational hygiene journals, and the ATF. For the broader picture, see our roundups on hearing protection statistics and on veterans’ hearing loss and tinnitus.
TL;DR
- Instructors at a federal training complex were exposed to peaks above 150 dB in most exercises (NIOSH HHE 2013-0124-3208, 2014).
- Indoor range instructors averaged 106 to 110 dBA over a full shift under NIOSH criteria (NIOSH HHE 2012-0065-3195, 2013).
- OSHA says impulse noise should not exceed 140 dB peak (OSHA 29 CFR 1910.95).
- Double protection added 15 to 20 dB of peak reduction over single protection (Murphy and Tubbs, Journal of Occupational and Environmental Hygiene 2007).
- Earmuffs worn over safety glasses cut peaks by only 12 and 18 dB in NIOSH tests (NIOSH HHE 2002-0131-2898, 2003).
- Only 4 of 10 hearing protectors met a 135 dB peak criterion at an instructor’s post on a Polish indoor range (Młyński and Kozłowski, 2019).
- Suppressors cut peaks by 20 to 28 dB at an instructor position one metre behind the shooter (Murphy et al., International Journal of Audiology 2018).
- Acoustic treatment of an Army indoor range raised M4 allowable rounds per day under double protection from 704 to as many as 2,021 (US Army Public Health Center TIP 51-006-1112).
- Swiss army instructors wore hearing aids at a rate ratio of 3.91 versus Swiss men (Rey et al., Sozial- und Praventivmedizin 1999).
- In 88% of rifle-caliber acoustic trauma incidents among Finnish conscripts, no hearing protector was used (Toivonen et al., IJERPH 2023).
- Firearm noise exposure was linked to 15% higher blood lead in US adults (Day et al., Environmental Epidemiology 2025).
1. Who Works the Firing Line: Range Workforce and Training Load
The firing line is the row of shooting positions where people fire, and instructors spend their working day beside it rather than visiting it a few times a year. That turns an occasional recreational hazard into a daily occupational one. NIOSH estimates that 40,000 to 60,000 workers are employed at US shooting ranges (NIOSH Publication 2013-104, Reducing Exposure to Lead and Noise at Outdoor Firing Ranges), a workforce that serves a much larger pool of officers and target shooters.
The training-load numbers explain why instructor exposure stacks up so fast. One instructor on a Polish indoor range trains about 18 shooters a day, and whether those shooters fire in groups of three or six made no significant difference to the instructor’s dose. The instructor is not exposed to one person’s shots: the instructor absorbs everyone’s.
| Metric | Value | Source |
|---|---|---|
| Firing ranges operating in the United States (NIOSH estimate) | 16,000 to 18,000 | NIOSH Publication 2010-113 |
| Non-military outdoor ranges in the United States | About 9,000 | NIOSH Publication 2013-104 |
| Workers employed at US shooting ranges | 40,000 to 60,000 | NIOSH Publication 2013-104 |
| Federal, state and local law enforcement officers in the US (all need firearms training) | More than 1.2 million | NIOSH Publication 2013-104 |
| US target shooters | About 15% of the population, or 34.4 million people | NIOSH Publication 2013-104 |
| Shooters one instructor typically trains in a day (Polish indoor range) | 18 | Młyński and Kozłowski, IJERPH 2019 |
| Instructor peak exposure with 6 shooters firing at once vs with 3 shooters firing at once | No significant difference (Wilcoxon p = 0.65) | Młyński and Kozłowski, IJERPH 2019 |
Most recent available data: the workforce and range counts come from NIOSH guidance published in 2010 and 2012, and no newer federal count of range workers has been published. Read the primary documents: NIOSH 2010-113 on indoor ranges and NIOSH 2013-104 on outdoor ranges.
2. Peak Sound Pressure at the Instructor’s Position
Peak sound pressure is the single highest instantaneous pressure of a shot, measured in decibels (dB), and it is the number that matters for sudden inner-ear damage. Every instructor measurement in this section sits above the 140 dB peak ceiling, and most sit more than 10 dB above it. Shotgun fire in a training house doorway reached 166.9 to 171.8 dB at instructor positions (NIOSH HHE 2013-0124-3208, 2014), up to 31.8 dB beyond the limit (171.8 minus 140).
Position matters as much as the weapon. In the same NIOSH evaluation, the instructor at position 1 during M4 rifle fire measured 158.6 to 164.2 dB while the instructor at position 2 on the same range measured 147.3 to 149.0 dB, a gap of roughly 10 to 15 dB. Two people doing the same job a few steps apart can carry very different risk.
| Metric | Value | Source |
|---|---|---|
| Instructors exposed to peaks above 150 dB | During most training exercises | NIOSH HHE 2013-0124-3208, 2014 |
| M4 rifle fire, Range 1: instructor at position 1 vs instructor at position 2 | 158.6 to 164.2 dB vs 147.3 to 149.0 dB | NIOSH HHE 2013-0124-3208, 2014 |
| Peaks during an outdoor instructor-led course in California (shotgun and two rifles) | 154.6 to 163.1 dB | NIOSH HHE 2011-0069-3140 |
| Peaks above 160 dB recorded in one minute of .30-06 rifle fire | 8 | NIOSH HHE 2011-0069-3140 |
| Peaks at an instructor position 1.1 m from shooters (pistols, submachine gun, shotguns), Polish indoor range | 145.9 to 158.1 dB LCpeak | Młyński and Kozłowski, IJERPH 2019 |
| Peaks measured on an acoustic mannequin head across police weapons (indoor and outdoor ranges) | 159 to 169 dB | NIOSH HHE 2002-0131-2898, 2003 |
Context note: the M134D minigun readings at a federal range (168.0 to 171.4 dB) appear in section 5, where a barrier test shows how much a simple wall can remove. Full instrument tables are in the NIOSH HHE 2013-0124-3208 report and the NIOSH HHE 2011-0069-3140 report.
3. Exposure Limits vs Full-Shift Averages
Two kinds of limit apply at a range. The peak limit (140 dB) caps any single impulse. The time-weighted average (TWA) caps the average noise across a shift: OSHA uses 90 dBA with a 5 dB exchange rate, while NIOSH uses 85 dBA with a 3 dB exchange rate. The exchange rate is how many decibels it takes to halve the allowed time, which is why the same shift can look acceptable under OSHA and far over the line under NIOSH.
Indoor range instructors in California averaged 106 to 110 dBA across a full shift under NIOSH criteria (NIOSH HHE 2012-0065-3195, 2013), more than 20 dB over the NIOSH limit. Instructors there exceeded the NIOSH limit, the OSHA action level and the OSHA permissible limit at once, and the hazard does not stay on the range: noise also leaks into nearby rooms.
| Metric | Value | Source |
|---|---|---|
| OSHA ceiling for impulsive or impact noise | Should not exceed 140 dB peak | OSHA 29 CFR 1910.95 |
| MIL-STD-1474E (April 2015) impulse peak requirement at the ear | Less than 140 dBP, protected or unprotected | AIHA The Synergist, 2016 |
| Peak limit in EU Directive 2003/10/EC vs Polish national regulation | 140 dB vs 135 dB LCpeak | Młyński and Kozłowski, IJERPH 2019 |
| Projected 8-hour exposure, outdoor range course in California (NIOSH criteria) | 88 to 97 dBA; all participants over the NIOSH limit, none over the OSHA PEL | NIOSH HHE 2011-0069-3140 |
| Indoor range instructors, full-shift average, OSHA criteria vs NIOSH criteria | 95 to 101 dBA vs 106 to 110 dBA | NIOSH HHE 2012-0065-3195, 2013 |
| Equivalent level inside an indoor range vs in an adjacent office | 122 dBA vs 78 dBA | Hayden et al., Applied Occupational and Environmental Hygiene 2003 |
| Level at which standard noise dosimeters clip (stop recording higher values) | About 145 dB | NIOSH HHE 2011-0069-3140 |
Outlier note: because dosimeters clip near 145 dB, NIOSH warns that gunfire TWA values underrepresent the real exposure, so every average in this table is likely an underestimate. OSHA also requires a new audiogram at least annually for workers at or above an 85 dBA 8-hour TWA (OSHA 29 CFR 1910.95). Our roundup on OSHA standard threshold shift statistics covers what those annual tests detect.
4. Double Hearing Protection: How Much It Really Adds
Double protection means wearing earplugs and earmuffs at the same time. The case for it is arithmetic: a 160 to 170 dB peak minus a single protector’s roughly 30 dB still lands at 130 to 140 dB, right at the ceiling. NIOSH testing showed that adding a second protector added 15 to 20 dB of peak reduction (Murphy and Tubbs, Journal of Occupational and Environmental Hygiene 2007), the margin that moves many weapons under the 140 dB line.
The weak points are fit and accessories. Safety glasses break the earmuff seal, and protectors rated for steady noise do not all handle impulses. On a Polish indoor range, more than half of the protectors tested failed a 135 dB peak criterion at the instructor’s post. Fit testing is the missing step, which our roundup on hearing protection fit testing explores in depth.
| Metric | Value | Source |
|---|---|---|
| Peak reduction from single protectors (earplugs, earmuffs or custom SWAT protectors) | 25 to 35 dB | Murphy and Tubbs, JOEH 2007 |
| Extra peak reduction from adding a second protector (plugs plus muffs) | 15 to 20 dB | Murphy and Tubbs, JOEH 2007 |
| Peak reduction from combined earmuff plus earplug, two tests | 46 and 50 dB | NIOSH HHE 2002-0131-2898, 2003 |
| Peak reduction from earmuffs worn over safety glasses, two tests | 12 and 18 dB | NIOSH HHE 2002-0131-2898, 2003 |
| Mean peak reduction from combined earmuffs and earplugs | 44 dB | NIOSH Publication 2010-113 |
| California instructors’ earmuffs: lab rating (NRR) vs estimated real-world (derated) attenuation | 25 dB vs 19 dB; dual protection estimated at 30 to 35 dB | NIOSH HHE 2011-0069-3140 |
| Attenuation assumed for dual vs single protection at a federal training complex | 34 dB vs 29 dB; bone conduction limits effective attenuation to about 41 dB | NIOSH HHE 2013-0124-3208, 2014 |
| Hearing protectors (of 10 tested) adequate at an instructor’s post: 135 dB criterion vs 140 dB criterion | 4 vs 6 | Młyński and Kozłowski, IJERPH 2019 |
Context note: bone conduction is sound that reaches the inner ear through the skull bones, bypassing any plug or muff, which is why stacking protectors has a ceiling. NIOSH also observed a few instructors at the outdoor ranges wearing only single protection and some earplugs that did not appear deeply inserted. See the Murphy and Tubbs study record and the NIOSH Fort Collins Police Services evaluation.
5. Engineering Controls: Barriers, Acoustic Treatment and Suppressors
Hearing protectors work at the ear; engineering controls work at the source or along the path, and they protect everyone on the line at once, including the instructor who cannot leave. Wall structures at an indoor range reduced noise by 29 to 44 dB (Hayden et al., Applied Occupational and Environmental Hygiene 2003), comparable to or larger than the 25 to 35 dB a single hearing protector gives (section 4), and it protects everyone in the room. Even a simple wooden barrier took about 10 dB off minigun peaks at an instructor position (first row of the table), a large gain for a low-tech fix that still left peaks well above 140 dB.
The US Army expresses the same idea as an allowable number of rounds per day (ANOR): how many shots a person can be exposed to before reaching an 85 dBA 8-hour dose. Acoustic treatment of an indoor Army range raised the M4 rifle allowance under double protection from 704 to between 1,216 and 2,021 rounds. Suppressors (devices on the muzzle that slow the escaping gas) help the instructor even more than the shooter, yet none of the studies below rated any combination as hearing safe.
| Metric | Value | Source |
|---|---|---|
| Minigun peaks at an instructor position: without barrier vs with wooden barrier | 168.0 to 171.4 dB vs 157.8 to 160.7 dB | NIOSH HHE 2013-0124-3208, 2014 |
| Noise reduction from wall structures at an indoor range | 29 to 44 dB | Hayden et al., AOEH 2003 |
| M4 rifle allowable rounds per day, multi-shooter, double protection: untreated range vs after acoustic treatment | 704 vs 1,216 to 2,021 | US Army Public Health Center, Technical Information Paper 51-006-1112 |
| 9 mm handgun allowable rounds per day after treatment, multi-shooter: single vs double protection | 1,795 vs 5,675 | US Army Public Health Center, Technical Information Paper 51-006-1112 |
| Suppressor peak reduction at the shooter’s ear vs at an instructor position about 1 m behind | 17 to 24 dB vs 20 to 28 dB | Murphy et al., International Journal of Audiology 2018 |
| Overall AR-15 suppression across test conditions | 7 to 32 dB; most conditions still above 140 dB peak near the shooter’s right ear | Lobarinas et al., International Journal of Audiology 2016 |
| Noise of the rifle’s bolt carrier group slamming back into place (separate from muzzle noise) | 132 dBZ | Agnew et al., JOEH 2024 |
| Silencers on the US National Firearms Act registry (data as of June 2026) | 6,342,117 | ATF Firearms Commerce in the United States, Annual Statistical Update 2025 |
Outlier note: the Army allowances use a conservative 85 dBA criterion and were measured on one indoor range in December 2011 (most recent available data: US Army Public Health Center TIP 51-006-1112). The suppressor figures come from the Murphy et al. 2018 study, whose authors recommend hearing protection whenever a gun is fired, suppressed or not.
6. Hearing Outcomes Among Instructors and Trainees
Outcome data on instructors specifically is thin, which is itself a finding: most hearing studies follow trainees, not the people who stand beside them all year. The instructor-specific numbers that do exist point the same way. Swiss army instructors and fortification guards wore hearing aids at a rate ratio of 3.91 (95% CI 3.09 to 4.96) compared with the male Swiss population (Rey et al., Sozial- und Praventivmedizin 1999), and their acute acoustic trauma rate showed no significant change over ten years while the rate in conscripts fell by 12% per year.
Prevention does show up in the data. US Marine Corps weapons instructors given an active (electronic) earmuff ended one year with better high-frequency hearing than a control cohort. Temporary threshold shift (TTS), a short-lived drop in hearing measured right after exposure, is the early warning sign tracked in the Fort Collins police data below. For the mechanics of damage that standard audiograms miss, see our cochlear synaptopathy statistics.
| Metric | Value | Source |
|---|---|---|
| Swiss army instructors and fortification guards wearing hearing aids vs Swiss men overall | RR 3.91 (95% CI 3.09 to 4.96) | Rey et al., Sozial- und Praventivmedizin 1999 |
| Number of US Marine Corps weapons instructors given an active earmuff vs in the control cohort; result | 127 vs 94; control high-frequency average 3 dB worse after 1 year | Federman et al., Annals of Work Exposures and Health 2022 |
| Police officers with a TTS of +10 dB or greater after indoor pistol qualification vs after shotgun qualification | 11 of 52 vs 1 of 14 (no shift above +20 dB) | NIOSH HHE 2002-0131-2898, 2003 |
| Finnish conscripts with new hearing loss from acute acoustic trauma over 10 years; share caused by rifle-caliber weapons | 1,617; 1,456 (90%) | Toivonen et al., IJERPH 2023 |
| Finnish rifle-caliber acoustic trauma cases (of 1,456) with a well-fitting hearing protector in use | 42 (3%) | Toivonen et al., IJERPH 2023 |
| Military cadets whose hearing was affected by acute acoustic trauma in firearms training: men vs women | 39% vs 21% (105 cadets) | Jovanovic et al., Journal of Medical Biochemistry 2025 |
| Estonian military personnel with slight to severe high-frequency hearing loss vs severe loss | 62.7% vs 9.3% (150 personnel) | Orru et al., Noise and Health 2020 |
| Brazilian military personnel who used ear protectors when shooting vs who never received guidance on using them | 92.3% vs 32.3% | Heupa et al., Brazilian Journal of Otorhinolaryngology 2011 |
Context note: the Swiss and Brazilian studies are older (most recent available data: Rey et al., 1999; Heupa et al., 2011), and the Brazilian average firearm noise of 125 dB(C) is a weighted level, not a peak. Primary records: Federman et al. 2022, Toivonen et al. 2023 and Jovanovic et al. 2025.
7. The Co-Exposure: Lead at the Same Ranges
Range noise rarely travels alone. Lead from primers and bullets is released at the same firing line, and the staff who clean and maintain ranges can face higher doses than the shooters. Cleaning behind a bullet trap produced an airborne lead level of 330 micrograms per cubic metre (NIOSH HHE 2012-0065-3195, 2013), 6.6 times the 50 microgram 8-hour limit (330 divided by 50), although it was measured over a single task rather than a full shift.
Ventilation works: after a new system was installed at a California indoor range, instructor air lead averaged 1.9 micrograms per cubic metre, down from 10.3 in 2009. The newest population data adds a twist: in US adults, reporting firearm noise exposure tracked blood lead more closely than reporting firearm use did.
| Metric | Value | Source |
|---|---|---|
| Highest instructor air lead sample at a California outdoor range vs occupational limit | 15 vs 50 micrograms per cubic metre | NIOSH HHE 2011-0069-3140 |
| Indoor range instructors’ full-shift air lead after new ventilation: range and average (2009 average) | 0.15 to 3.8, average 1.9 (10.3 in 2009) micrograms per cubic metre | NIOSH HHE 2012-0065-3195, 2013 |
| Hazardous materials technician full-shift air lead on one day vs OSHA action level | 34 vs 30 micrograms per cubic metre | NIOSH HHE 2012-0065-3195, 2013 |
| Blood lead of a rifle team coach using a contaminated indoor range | 44 micrograms per decilitre | NIOSH Publication 2010-113 |
| Difference in blood lead, US adults reporting firearm noise exposure vs not | 15% higher (95% CI 7%, 23%) | Day et al., Environmental Epidemiology 2025 |
| Difference in blood lead, adults reporting 10,000+ rounds fired vs 0 rounds | 21% higher (95% CI -5%, 54%) | Day et al., Environmental Epidemiology 2025 |
| Blood lead increase per 100,000 shots, Berlin special police | +0.34% (0.02 to 0.66%, P = 0.037) | Witt et al., Journal of Cachexia, Sarcopenia and Muscle 2023 |
Context note: the Berlin study also found respiratory symptoms during shooting practice in 64% of the high-exposure group vs 21% of the low-exposure group (P < 0.001). Read the Day et al. 2025 NHANES analysis and the Berlin shooting range study.
Summary: Shooting Range Instructor Noise by the Numbers
| Metric | Value | Source |
|---|---|---|
| Instructors exposed to peaks above 150 dB | During most training exercises | NIOSH HHE 2013-0124-3208, 2014 |
| Peaks 1.1 m from shooters, Polish indoor range | 145.9 to 158.1 dB LCpeak | Młyński and Kozłowski, IJERPH 2019 |
| OSHA impulse noise ceiling | 140 dB peak | OSHA 29 CFR 1910.95 |
| Indoor range instructors, full-shift average (NIOSH criteria) | 106 to 110 dBA | NIOSH HHE 2012-0065-3195, 2013 |
| Inside an indoor range vs adjacent office | 122 dBA vs 78 dBA | Hayden et al., AOEH 2003 |
| Workers at US shooting ranges | 40,000 to 60,000 | NIOSH Publication 2013-104 |
| Firing ranges in the US | 16,000 to 18,000 | NIOSH Publication 2010-113 |
| Extra peak reduction from double protection | 15 to 20 dB | Murphy and Tubbs, JOEH 2007 |
| Combined earmuff plus earplug peak reduction, two tests | 46 and 50 dB | NIOSH HHE 2002-0131-2898, 2003 |
| Earmuffs over safety glasses, peak reduction | 12 and 18 dB | NIOSH HHE 2002-0131-2898, 2003 |
| Suppressor peak reduction at instructor position | 20 to 28 dB | Murphy et al., IJA 2018 |
| AR-15 rifle conditions with suppressor still above 140 dB peak near the shooter’s right ear | Most conditions tested | Lobarinas et al., IJA 2016 |
| M4 allowable rounds per day, double protection: untreated vs treated range | 704 vs 1,216 to 2,021 | US Army Public Health Center TIP 51-006-1112 |
| Swiss army instructors’ hearing aid use vs Swiss men | RR 3.91 (95% CI 3.09 to 4.96) | Rey et al., 1999 |
| Marine Corps instructors without active earmuff, high-frequency average after 1 year | 3 dB worse | Federman et al., 2022 |
| Finnish rifle-caliber acoustic trauma incidents with no hearing protector | 88% | Toivonen et al., IJERPH 2023 |
| Blood lead with firearm noise exposure, US adults | 15% higher (95% CI 7%, 23%) | Day et al., 2025 |
Methodology and Sources
- NIOSH Health Hazard Evaluation 2013-0124-3208 (2014): noise at a federal agency’s security training complex in Tennessee, instructor positions.
- NIOSH Health Hazard Evaluation 2011-0069-3140: noise and lead at an outdoor firing range in California.
- NIOSH Health Hazard Evaluation 2012-0065-3195 (2013): followback evaluation of lead and noise at a California indoor range.
- NIOSH Health Hazard Evaluation 2002-0131-2898 (2003): Fort Collins Police Services, Colorado.
- NIOSH Publication 2010-113 and NIOSH Publication 2013-104: workplace solutions for indoor and outdoor firing ranges.
- Murphy and Tubbs, Journal of Occupational and Environmental Hygiene 2007 and Hayden et al., Applied Occupational and Environmental Hygiene 2003.
- Murphy et al., International Journal of Audiology 2018, Lobarinas et al., International Journal of Audiology 2016 and Agnew et al., JOEH 2024: suppressor studies.
- Młyński and Kozłowski, IJERPH 2019: level-dependent hearing protectors for an indoor range instructor.
- US Army Public Health Center, Technical Information Paper 51-006-1112: allowable rounds before and after noise control treatment.
- OSHA 29 CFR 1910.95 and AIHA The Synergist on MIL-STD-1474E (2016).
- ATF Firearms Commerce in the United States, Annual Statistical Update 2025, Exhibit 8.
- Hearing outcomes: Federman et al. 2022, Rey et al. 1999, Toivonen et al. 2023, Jovanovic et al. 2025, Orru et al. 2020 and Heupa et al. 2011.
- Lead: Day et al., Environmental Epidemiology 2025 and Witt et al. 2023.
- Data watch: most instructor-specific field data comes from NIOSH evaluations conducted between 2002 and 2013, because we found no newer published NIOSH firing-range evaluation of instructors; treat these as the most recent available data. Two NIOSH reports are internally inconsistent on headcounts (HHE 2011-0069-3140 says eight students and five instructors gave 14 dosimetry measurements, while its table lists six student and eight instructor measurements; HHE 2012-0065-3195 says six instructors were monitored while its table lists nine instructor dosimeters), so we report only their measured ranges. In Toivonen et al. 2023, the abstract gives 1,277 (88%) incidents without a protector while the results section gives 1,266 (87%); we cite the abstract. The ATF registry total covers all registered silencers, not ones used at ranges, and the 2025 update reports data as of June 2026. All TWA values from gunfire are likely underestimates because dosimeters clip near 145 dB.
Last updated: October 18, 2026. We update this roundup quarterly, and the next refresh is expected when ATF publishes its Annual Statistical Update 2026 or NIOSH releases a new firing-range Health Hazard Evaluation.