A hearing conservation program (HCP) under OSHA 29 CFR 1910.95 is not optional for employers whose workers are exposed to noise at or above 85 decibels averaged over an 8-hour workday. The standard requires five interlocking elements — noise monitoring, audiometric testing, hearing protection, training, and recordkeeping — all of which must be documented and maintained. This guide explains each requirement in plain language, who is covered, and what a compliant program looks like in practice.
- Who needs a hearing conservation program
- The five required elements of OSHA 1910.95
- Element 1: Noise monitoring
- Element 2: Audiometric testing
- Element 3: Hearing protection devices
- Element 4: Training
- Element 5: Recordkeeping
- Understanding standard threshold shifts (STS)
- State plan variations
- Frequently asked questions
Who Needs a Hearing Conservation Program
OSHA 1910.95 applies to all general industry employers (manufacturing, processing, warehousing, utilities, etc.) when any worker’s time-weighted average (TWA) noise exposure equals or exceeds the action level of 85 dBA over an 8-hour workday. This threshold is the trigger for the full program — monitoring, audiometric testing, HPDs, training, and recordkeeping.
Key coverage points:
- General industry: 29 CFR 1910.95 covers manufacturing, warehousing, food processing, healthcare, and most non-construction, non-mining employers.
- Construction: 29 CFR 1926.52 applies. The action level is 90 dBA TWA, and audiometric testing is not required — only noise controls and hearing protection.
- Mining: MSHA 30 CFR Part 62 applies. Requirements differ from OSHA in monitoring methodology and audiometric testing standards.
- Federal agencies: 29 CFR 1960 applies. Requirements are substantively equivalent to 1910.95.
- State plan states: 22 states operate their own OSHA plans. Requirements must be at least as protective as federal 1910.95. Some states (Oregon, Washington) have additional requirements.
The Five Required Elements of OSHA 1910.95
Element 1: Noise Monitoring (1910.95(c)–(d))
Before enrolling workers or providing hearing protection, employers must measure noise exposure to determine who is covered. OSHA 1910.95(c) requires monitoring whenever there is information indicating workers may be exposed at or above the 85 dBA action level.
What Monitoring Must Cover
- All steady-state, impulsive, and intermittent noise must be integrated into the TWA measurement
- All noise levels from 80 to 130 dBA must be captured (OSHA uses the 80 dBA threshold for dosimeter settings, not just the 85 dBA action level)
- Monitoring must be repeated when production processes, equipment, or controls change in ways that may increase exposure
Monitoring Methods
| Method | What It Measures | Best For |
|---|---|---|
| Personal noise dosimeter | Individual worker’s actual TWA over the workday | Mobile workers, variable exposures |
| Sound level meter (area monitoring) | Noise level at a fixed location or point in time | Fixed workstations, initial screening |
| Engineering noise assessment | Equipment-specific SPL used to predict TWA | Equipment purchase decisions, engineering control evaluation |
Under 1910.95(e), affected workers and their representatives have the right to observe noise monitoring. This requirement is often overlooked — if workers are not notified of scheduled monitoring and given the opportunity to observe, the monitoring may be procedurally deficient.
Element 2: Audiometric Testing (1910.95(d)–(h))
Audiometric testing is the cornerstone of the HCP — it provides the longitudinal record that demonstrates whether the program is protecting worker hearing. All workers exposed at or above the 85 dBA action level must be enrolled.
Baseline Audiogram
A baseline audiogram must be established within 6 months of first exposure at or above the action level (or within 1 year if a mobile audiometric testing van is used). The baseline must be preceded by at least 14 hours without workplace noise exposure to prevent temporary threshold shift (TTS) from corrupting the results. Soundtrace’s system flags same-day baseline tests that may have been preceded by noise exposure.
Annual Audiograms
Annual audiograms must be conducted within 1 year of the baseline. Each annual audiogram is compared to the baseline to detect any standard threshold shift. OSHA specifies testing at 500, 1000, 2000, 3000, 4000, and 6000 Hz — though 500 Hz is for reference and the STS calculation uses 2000, 3000, and 4000 Hz only.
Audiometer and Testing Environment Requirements
- Audiometers must comply with ANSI S3.6
- Acoustic calibration (biologic check) must be performed before each day of testing
- Exhaustive calibration to ANSI standards must be performed at least annually
- Background noise levels in the testing environment must not exceed OSHA Appendix D limits (maximum 40 dB SPL at 500 Hz, scaling by frequency)
Audiometric Test Personnel
Under 1910.95(g)(3), audiometric tests must be administered by a licensed or certified audiologist, otolaryngologist, physician, or technician supervised by an audiologist, otolaryngologist, or physician. In Oregon and Washington, technicians must be CAOHC-certified. In most other states, demonstrated competence under professional supervision satisfies the standard — this is the regulatory framework Soundtrace operates under.
Element 3: Hearing Protection Devices (1910.95(i)–(j))
Hearing protection must be offered (not just made available) to all workers exposed at or above the action level. The requirements differ between the action level and the PEL:
| Exposure Level | HPD Requirement |
|---|---|
| 85–89 dBA TWA (action level to PEL) | Employer must offer HPDs at no cost; workers may voluntarily wear them |
| 90+ dBA TWA (at or above PEL) | HPD use is mandatory; employer must enforce actual use |
| Any level with confirmed STS | HPD use is mandatory even if exposure is below 90 dBA |
| Any level, new hire baseline pending | HPDs must be worn until baseline is established |
Attenuation Adequacy
HPDs must provide enough attenuation to reduce worker exposure to below 90 dBA (or 85 dBA for workers with STS). OSHA requires using the derated NRR — the labeled NRR is reduced by 50% before calculating effective protection. An earplug labeled NRR 33 provides an estimated 16.5 dB of real-world protection for most workers. Employers must document that the HPD selection provides adequate derated attenuation for each worker’s actual exposure level.
An employer who issues foam earplugs with NRR 33 to a worker exposed at 95 dBA TWA, without calculating derated NRR, may be providing inadequate protection on paper. Derated NRR: (33 - 7) / 2 = 13 dB. Effective exposure: 95 - 13 = 82 dBA — which is below 85, so protection is adequate. But without this calculation documented, the inspector has no way to verify adequacy and may cite the employer.
Element 4: Training and Education (1910.95(k))
Annual training is required for all workers enrolled in the HCP. Training must cover:
- Effects of noise on hearing
- Purpose of hearing protection, advantages, disadvantages, and attenuation of various types
- Instructions on selection, fitting, use, and care of hearing protectors
- Purpose of audiometric testing and a description of the test procedures
Training must be conducted at least annually and records must be retained. Employers often satisfy the annual requirement with a sign-in sheet, but OSHA also expects some evidence of the actual content delivered. Online training with course completion records satisfies both requirements.
Element 5: Recordkeeping (1910.95(m))
OSHA 1910.95(m) requires specific retention periods for different record types:
| Record Type | Required Retention | Practical Notes |
|---|---|---|
| Noise exposure measurement records | 2 years | Minimum; retain longer for WC defense |
| Audiometric test records | Duration of employment + 30 years post-employment | The critical long-retention record; must include all baseline and annual audiograms |
| HPD issuance records | Not specified; retain for WC defense | Document who received what HPD on what date |
| Training records | Not specified in 1910.95; retain indefinitely | Sign-in sheets and training completion records |
OSHA requires audiometric records to be retained for the duration of employment plus 30 years after the worker leaves. A worker who starts at age 22 and retires at 62 creates a record that must be retained until age 92 — 70 years total. For multi-site employers with turnover, this creates a substantial long-term records management obligation. Soundtrace stores audiometric records indefinitely with a complete chain-of-custody audit trail.
Understanding Standard Threshold Shifts (STS)
A standard threshold shift (STS) is a change in hearing threshold, relative to the baseline audiogram, of an average of 10 dB or more at 2000, 3000, and 4000 Hz in either ear. STS triggers a specific sequence of required employer actions:
- Within 30 days: Retest the worker to confirm the STS (or use the original annual audiogram if reliable)
- If STS is confirmed: Notify the worker in writing within 21 days
- If not using HPDs: Fit the worker with hearing protection, train on proper use, and require use
- If using HPDs: Refit, retrain, or require use of more protective HPDs
- If STS is work-related: Record on OSHA 300 log
- Evaluate whether a revised baseline is appropriate
OSHA permits but does not require age correction (presbycusis correction) when calculating STS. Age-corrected STS calculations use OSHA Appendix F tables to subtract expected age-related hearing loss. The result: a worker with significant age-related hearing loss may show less STS when age-corrected, potentially avoiding recordable STS events. Some employers use age correction systematically; others do not. The choice must be consistent and documented.
State Plan Variations
22 states and territories operate their own OSHA-approved plans. All must be at least as protective as federal 1910.95. Notable variations:
| State | Key Variation |
|---|---|
| Oregon (OR-OSHA) | Audiometric technicians must be CAOHC-certified or under licensed audiologist supervision (OAR 437-002-0144) |
| Washington (WISHA) | Same CAOHC/supervision requirement as Oregon (WAC 296-817-400) |
| California (Cal/OSHA) | Additional requirements for noise-exposed construction workers; some differences in dosimeter exchange rate interpretation |
| Michigan (MIOSHA) | MIOSHA Part 380 is substantively equivalent to federal 1910.95; independent enforcement authority |
Frequently Asked Questions
The action level that triggers mandatory HCP requirements is 85 dBA as an 8-hour time-weighted average (TWA). This is calculated using OSHA’s 5 dB exchange rate and must include all noise between 80 and 130 dBA. Workers at or above this level must be enrolled in monitoring, audiometric testing, HPD, training, and recordkeeping programs.
No — only workers whose 8-hour TWA equals or exceeds 85 dBA. A worker who spends 4 hours in a 90 dBA area and 4 hours in a quiet office may have a TWA below 85 dBA and may not require enrollment. Personal noise dosimetry is the most accurate way to determine individual exposure and identify who must be enrolled.
Yes, provided the audiometer meets ANSI S3.6 requirements and the testing environment meets OSHA Appendix D background noise limits. Microprocessor audiometers — the type used by Soundtrace — are explicitly recognized in 1910.95(g)(3) as appropriate testing equipment when supervised by a qualified professional. The key requirements are calibration documentation and background noise verification.
OSHA requires audiometric records to be retained for the duration of employment plus 30 years. This means a worker who leaves employment must have their records retained for an additional 30 years — making the total retention period potentially 50 or more years for a long-tenured employee. Noise exposure measurement records have a shorter 2-year minimum retention.
OSHA 1910.95(g)(3) specifies that audiometric tests must be conducted by a licensed or certified audiologist, otolaryngologist, or physician, OR by a technician certified by the Council for Accreditation in Occupational Hearing Conservation (CAOHC), OR by a technician who demonstrates competence under the supervision of an audiologist, otolaryngologist, or physician. Oregon and Washington require CAOHC certification specifically; most other states accept the competence-under-supervision pathway.
A Complete HCP — Without the Complexity
Soundtrace provides the full 1910.95 program in one platform: noise monitoring, ANSI-compliant audiometric testing, automated STS detection, HPD fit testing, training records, and 30-year retention. No booth required.
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