Audiometric testing is the only way to know whether your hearing conservation program is actually protecting workers’ hearing. OSHA requires it for all workers exposed at or above 85 dBA TWA, without cost to the employee. But the compliance obligation is only part of the story — the annual audiogram is also the surveillance instrument that catches NIHL at Stage 1 or 2, when intervention can still prevent progression to recordable, disabling, and litigated hearing loss. This guide covers what audiometric testing is, who needs it, how to run it correctly, what the results mean, and how in-house testing compares to mobile van programs.
Soundtrace replaces the mobile van with an in-house audiometric testing platform — employees test in under 9 minutes, STS is flagged automatically, and professional audiologist review is built into every program.
OSHA 1910.95(g) requires audiometric testing at no cost to employees for all workers exposed at or above 85 dBA TWA. Every covered worker needs a baseline audiogram within 6 months of first exposure and an annual audiogram every 12 months thereafter. STSs must be identified by a professional supervisor and acted upon within 21 days of determination.
What Is Audiometric Testing?
Audiometric testing (hearing testing) measures a person’s hearing thresholds — the quietest sound audible at each tested frequency. In occupational hearing conservation, pure-tone air conduction audiometry is conducted at 500, 1000, 2000, 3000, 4000, and 6000 Hz (and typically 8000 Hz) in each ear. The test generates an audiogram — a graph of hearing thresholds across frequencies — that is compared to the worker’s baseline audiogram to detect changes over time.
The clinical significance for OSHA purposes is straightforward: noise-induced hearing loss produces a characteristic notch at 4000 Hz that appears on the audiogram long before the worker notices any functional hearing impairment. Audiometric surveillance catches this notch when it is still shallow — at Stage 1 or 2 — when HPD upgrades, fit testing, and engineering controls can prevent progression to Stage 3 and recordable, disabling hearing loss.
Who Needs Audiometric Testing Under OSHA?
All employees exposed to noise at or above the action level of 85 dBA as an 8-hour time-weighted average (TWA) must be enrolled in the hearing conservation program and must receive audiometric testing at the employer’s expense. This threshold applies regardless of whether the employee wears hearing protection — HPD use does not exempt a worker from audiometric testing requirements.
Some employers mistakenly believe that providing and requiring hearing protection eliminates the obligation to conduct annual audiograms. It does not. If a worker is exposed at or above 85 dBA TWA and is enrolled in the HCP, they must receive annual audiograms regardless of whether they consistently wear their HPD. The audiogram is the surveillance instrument; the HPD is the prevention mechanism. Both are required.
Baseline vs. Annual Audiograms
| Audiogram Type | When Required | Purpose | Key Requirements |
|---|---|---|---|
| Baseline audiogram | Within 6 months of first enrollment (1 year if using mobile van) | Establishes reference thresholds against which all future annual audiograms are compared for STS calculation | 14-hour quiet period before testing; must be retained for employment + 30 years; cannot be changed without documented clinical justification |
| Annual audiogram | Within 12 months of previous audiogram, every year while enrolled | Detects threshold shift vs. baseline; enables STS calculation; documents hearing status progression | 14-hour quiet period; professional supervisor review required; STS determination triggers 21-day notification |
| Retest audiogram | Within 30 days of annual audiogram showing STS (optional for employer) | Confirms or resolves apparent STS before triggering all required follow-up obligations | If retest resolves STS, use retest results; if retest confirms STS, proceed with all 1910.95(g)(8) obligations |
Technical Requirements
OSHA specifies technical requirements for audiometric testing equipment and conditions under 1910.95 Appendix D (for pure-tone audiometers) and Appendix E (for microprocessor audiometers). Key requirements:
- Ambient noise limits: The testing environment must meet maximum permissible ambient noise levels per Appendix D (for booth-based programs) or Appendix E (for microprocessor/boothless programs). Soundtrace stores event-level ambient noise data linked to each threshold response event for evidentiary validation.
- Calibration: Audiometric equipment must be calibrated per manufacturer specifications and ANSI standards. Annual exhaustive calibration is required.
- 14-hour quiet period: Workers must not be exposed to noise above 80 dBA for 14 hours before testing to prevent temporary threshold shift (TTS) from masking permanent shifts.
Who Can Conduct Audiometric Tests?
OSHA 1910.95(g)(3) allows audiometric tests to be conducted by:
- A licensed or certified audiologist, otolaryngologist, or other qualified physician
- A technician who is certified by the Council for Accreditation in Occupational Hearing Conservation (CAOHC) or who has satisfactorily demonstrated competence under the supervision of the professional supervisor
- For microprocessor audiometers, the standard explicitly recognizes that the automation may reduce or eliminate the need for technician certification — a competence demonstration standard applies
Regardless of who conducts the test, a professional supervisor (physician, audiologist, or other qualified professional) must review audiograms and make STS determinations. The technician administers; the professional supervisor determines clinical significance.
Standard Threshold Shift: Detection and Required Actions
An STS is a 10 dB or greater average change in hearing threshold at 2000, 3000, and 4000 Hz in either ear compared to the baseline audiogram. The STS calculation is performed per ear independently. Age correction using OSHA Appendix F may be applied before calculating whether a 10 dB average shift has occurred.
In-House vs. Mobile Van: Key Comparison
| Factor | Mobile Van Program | In-House (Soundtrace) |
|---|---|---|
| Test frequency | Annual site visit; testing window limited to van schedule | Test any time; on-demand retests; 30-day STS retest window easily met |
| Record access | Records held by van vendor; employer has limited direct access | Employer-controlled cloud portal; all records accessible immediately |
| PS review speed | Batch review after van visit; may be weeks before STS is identified | Per-audiogram review; STS flagged within days of testing |
| HIPAA/security | Variable; most van vendors have no BAA or SOC 2 certification | SOC 2 certified; HIPAA compliant; BAA with every client |
| Worker disruption | Extended testing sessions; workers away from post | Under 9 minutes per worker; minimal workflow disruption |
| Long-term cost | Per-test fees + travel; costs increase with workforce size | Flat per-worker annual fee; no incremental test cost |
Frequently asked questions
In-House Audiometric Testing in Under 9 Minutes Per Worker
Soundtrace replaces the mobile van with cloud-connected in-house testing: PS review per audiogram, STS flagging within days, HIPAA-compliant records, and complete OSHA documentation — all in one platform.
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