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OSHA Action Level vs. PEL for Noise: What the 5 dB Difference Means
Jeff WilsonCEO & Founder12 min readMarch 1, 2026
OSHA Compliance·Noise Exposure·12 min read·Updated March 2026
OSHA’s noise standard establishes two exposure thresholds: the action level at 85 dBA TWA and the permissible exposure limit (PEL) at 90 dBA TWA. The 5 dB gap between them is not a gray zone — each level triggers a distinct and separate set of employer obligations. Understanding what each threshold actually requires is the foundation of a compliant hearing conservation program under 29 CFR 1910.95.
Soundtrace automatically classifies workers against both the 85 dBA action level and 90 dBA PEL, combining noise monitoring data, audiometric history, and REAT-based HPD fit testing results into a single unified worker profile viewable in the cloud portal.
PEL — additionally requires feasible engineering and administrative controls
5 dB
Exchange rate — every 5 dB increase halves max permissible exposure time
140 dB
Impulse noise ceiling — no exposure permitted above this peak level at any duration
The core distinction in one sentence
The action level (85 dBA) requires a hearing conservation program. The PEL (90 dBA) additionally requires engineering and administrative controls to reduce the noise — hearing protection alone is not enough above the PEL when feasible controls exist.
OSHA Noise Exposure Thresholds — What Each Level Triggers
The 5 dB gap between the action level and PEL is the difference between “run a program” and “also reduce the noise itself.”
The Action Level: 85 dBA TWA
The action level under 29 CFR 1910.95 is an 8-hour time-weighted average noise exposure of 85 dBA. When a worker’s measured or anticipated TWA equals or exceeds this level, the employer must implement a full hearing conservation program. The six required program elements:
1
Noise monitoring under 1910.95(d)
Measure or assess worker TWA. Notify workers of individual results. Re-monitor whenever a change in process, equipment, or controls may increase exposures.
2
Audiometric testing under 1910.95(g)
Baseline audiogram within 6 months of enrollment (1 year if mobile van used, with continuous HPD use). Annual audiograms each year thereafter. All at no cost to the employee.
3
HPD provision under 1910.95(i)
Provide a variety of hearing protectors at no cost. HPD use is mandatory above the PEL and following a confirmed STS. Between 85–90 dBA, HPDs must be available but employee use is not mandated.
4
Annual training under 1910.95(k)
Cover effects of noise on hearing, HPD selection/fitting/care, and audiometric testing purpose. Repeat every 12 months. Must be in a language the employee understands.
5
Recordkeeping under 1910.95(m)
Retain noise monitoring records for 2 years; audiometric records for duration of employment plus 30 years.
6
Worker notification under 1910.95(e)
Inform each worker of their individual monitoring results. Workers have the right to observe monitoring. Separate from the 21-day STS notification requirement under 1910.95(g)(8).
▶ Reaching the action level does not require engineering controls. It requires a hearing conservation program. Engineering controls become mandatory only when exposure exceeds the 90 dBA PEL.
The PEL: 90 dBA TWA
The PEL is the maximum permissible noise dose for an 8-hour shift. When a worker’s TWA equals or exceeds 90 dBA, all six action-level HCP requirements continue to apply — and the employer must additionally implement feasible engineering and administrative controls.
⚠ Engineering Controls (First Priority)
Implement feasible engineering controls to reduce noise at the source: machine enclosures, vibration isolation, damping materials, quieter equipment substitution.
Must be implemented even if HPDs alone could theoretically reduce effective exposure to the PEL. Feasibility is determined by technical practicability, not cost alone.
Rotation schedules to reduce individual exposure time, restricting access to high-noise areas, scheduling noisy operations for low-occupancy periods.
Used where engineering controls cannot fully reduce exposure below the PEL. Combined with engineering controls, not instead of them.
The most common PEL compliance error
Employers who exceed 90 dBA TWA and respond only by issuing hearing protection — without implementing feasible engineering or administrative controls — are in violation of 1910.95(b)(1). HPD-only programs above the PEL are not compliant when feasible controls exist, regardless of how effective the HPDs are.
Side-by-Side: What Each Threshold Triggers
Employer Obligations at Each Threshold — Full Comparison
PEL obligations stack on top of action-level obligations. Everything required at 85 dBA is also required at 90 dBA and above.
The 5 dB Exchange Rate: Maximum Permissible Exposure Times
OSHA uses a 5 dB exchange rate: for every 5 dB increase in noise level, the maximum permissible exposure time is halved. This is how the PEL translates from a single number (90 dBA TWA) into a practical table of level-specific time limits under Table G-16.
Noise Level
Max Duration
Dose at 8 hrs
Status
85 dBA
16 hours
50%
Action level threshold
90 dBA (PEL)
8 hours
100%
PEL — engineering controls required
95 dBA
4 hours
200% per 8 hrs
Significantly above PEL
100 dBA
2 hours
400% per 8 hrs
Engineering controls critical
105 dBA
1 hour
800% per 8 hrs
Dual HPD often required
110 dBA
30 minutes
—
Dual HPD and controls mandatory
115 dBA
15 minutes max
—
Absolute ceiling — no exposure above 115 dBA
OSHA vs. NIOSH: Different Settings, Different Purposes
✅ OSHA Settings — Use for 1910.95 Compliance
Exchange rate: 5 dB
Criterion level: 90 dBA (100% dose = PEL)
Action level: 85 dBA (50% dose)
Use for: All HCP enrollment, 300 Log, HPD adequacy, OSHA inspection compliance
⚠ NIOSH Settings — Not for OSHA Compliance
Exchange rate: 3 dB (stricter)
Criterion level: 85 dBA (REL)
Result: Higher TWA from same exposure — incompatible with 1910.95
Use for: Occupational health goals beyond legal minimum; not OSHA compliance
Frequently asked questions
What is the OSHA noise action level?
The OSHA action level for noise is 85 dBA TWA over an 8-hour shift. At or above this level, employers must implement a full hearing conservation program: noise monitoring, baseline and annual audiometric testing, HPD availability, annual training, and recordkeeping. Engineering controls are not required at the action level.
What is the OSHA noise PEL?
The PEL is 90 dBA TWA over 8 hours. Above the PEL, all HCP requirements continue to apply and the employer must additionally implement feasible engineering and administrative controls to reduce noise exposure. HPD use becomes mandatory rather than voluntary.
What is the difference between the action level and the PEL?
The action level (85 dBA) requires a hearing conservation program. The PEL (90 dBA) adds the requirement to implement feasible engineering and administrative controls to actually reduce the noise. The difference is between protecting workers with a program versus also reducing the hazard at the source.
Does the action level require engineering controls?
No. Engineering controls are required under 1910.95(b)(1) only when exposure exceeds the 90 dBA PEL and feasible controls are available. Workers between 85 and 90 dBA require the full HCP but not necessarily engineering controls.
Can hearing protection replace engineering controls above the PEL?
No. Under 1910.95(b)(1), when the PEL is exceeded and feasible controls exist, those controls must be implemented regardless of HPD effectiveness. HPDs can address residual exposure after controls but cannot substitute for controls that are feasible.
What is OSHA’s 5 dB exchange rate?
For every 5 dB increase in noise level, the maximum permissible exposure time is halved. At 90 dBA, 8 hours. At 95 dBA, 4 hours. At 100 dBA, 2 hours. At 115 dBA, 15 minutes is the absolute maximum under any circumstances.
Know Exactly Where Every Worker Stands Against Both Thresholds
Soundtrace tracks noise exposure against the 85 dBA action level and 90 dBA PEL automatically, combining dosimetry data, audiometric history, and REAT-based HPD fit testing into a single unified worker profile viewable in the cloud portal.
Jeff Wilson is the CEO and Founder of Soundtrace. He started the company after seeing firsthand how outdated and fragmented hearing conservation was across industries. Jeff brings a hands-on approach to building technology that makes OSHA compliance simpler and hearing protection more effective for the employers and workers who need it most.
