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If your employees are exposed to hazardous noise at work, OSHA requires you to provide regular hearing tests. But “hearing test” covers a lot of ground — and the difference between a compliant occupational audiogram and a general hearing screening matters for both legal protection and genuine hearing health. Here’s what employers need to know.
Soundtrace provides OSHA-compliant employee audiometric testing without a sound booth — at your facility, on your schedule, with professional supervisor review and automated records included in every program.
An occupational hearing test — formally called pure-tone audiometry — measures the softest sound a person can hear at specific frequencies. The test produces an audiogram: a graph showing hearing thresholds at each tested frequency in each ear.
OSHA requires testing at 500, 1000, 2000, 3000, 4000, and 6000 Hz — the frequencies most relevant for detecting noise-induced hearing loss and for capturing the speech-frequency range important for occupational communication. The results are measured in decibels hearing level (dB HL), with 0–25 dB HL considered normal hearing for adults.
The occupational audiogram serves two distinct purposes that a general hearing screening does not:
This individual-comparison approach is fundamentally different from a general hearing screening that compares results to population norms. An employee who begins employment with excellent hearing (5 dB HL average) and deteriorates to 20 dB HL average over 5 years has lost 15 dB of sensitivity — which a norm-based screening might classify as “within normal limits” while the occupational audiogram would flag as a significant shift.
▶ Bottom line: Occupational audiometric testing is surveillance, not screening. Its value comes from tracking individual change over time — which is why the baseline audiogram and continuous annual testing are both essential.
OSHA’s hearing conservation standard at 29 CFR 1910.95 requires audiometric testing for employees whose noise exposures equal or exceed 85 dBA as an 8-hour time-weighted average (TWA). This threshold — the action level — applies to all general industry employers covered by OSHA.
The exposure assessment that determines who needs testing must include all noise sources encountered during the work shift. An employee who spends 4 hours at 90 dBA and 4 hours at 80 dBA has a TWA exposure above the action level even though half the shift was below it. Personal noise dosimetry, rather than spot measurements of individual equipment, is the appropriate method when exposures are variable across the shift.
Employees who should be evaluated for enrollment include:
When in doubt, measure first. The cost of monitoring employees to confirm exposures are below the action level is substantially lower than the cost of enrolling workers whose exposures were assumed to be below threshold and later discovering they were not.
▶ Bottom line: Enrollment in the hearing conservation program — and therefore audiometric testing — is triggered by measured noise exposure at or above 85 dBA TWA. When exposure is uncertain, measure rather than assume.
The baseline audiogram is the foundational test — the reference point against which all future changes are measured. It must be established within 6 months of an employee’s first exposure at or above the action level (or within 1 year if a mobile testing van is the sole available method). The critical requirement: the employee must have been away from workplace noise for at least 14 hours before the baseline test, to ensure temporary threshold shift has resolved and the measured thresholds represent the employee’s true stable hearing level.
Annual audiograms are required every 12 months for all enrolled employees. Each annual audiogram is compared to the established baseline (or a revised baseline, if applicable) to detect Standard Threshold Shifts. The annual audiogram also confirms that the employee’s hearing status is current and documented, creating a continuous surveillance record across their employment.
A third type — the retest audiogram — may be conducted within 30 days of an annual audiogram that shows an STS. The retest is used to confirm or rule out the shift as a persistent finding vs. a temporary artifact of pre-test noise exposure.
▶ Bottom line: The baseline audiogram sets the reference; annual audiograms detect change. Both are required and serve distinct functions in the surveillance program.
A standard occupational audiometric test follows this sequence:
The test environment must have ambient noise levels low enough to avoid masking the test tones at the lowest frequencies tested. Traditional programs use a sound booth; modern digital programs use validated high-attenuation circumaural headsets with real-time ambient noise monitoring to achieve equivalent test validity outside a booth.
Employees should avoid loud noise — including recreational noise like concerts, power tools, or firearms — for at least 14 hours before an audiometric test. Inform employees of this requirement at least 24–48 hours before their scheduled test, not the morning of.
▶ Bottom line: Audiometric testing takes 10–20 minutes per employee and requires a quiet test environment, calibrated equipment, a trained technician, and a professional supervisor who reviews results. All four elements are required for a compliant OSHA program.
Audiogram results are plotted as a graph with frequency on the horizontal axis (low to high, left to right) and hearing threshold level on the vertical axis (better hearing toward the top, worse hearing toward the bottom). Standard symbols: O for right ear, X for left ear.
The audiogram shape carries diagnostic information. Noise-induced hearing loss characteristically produces a “notch” pattern — a dip in thresholds centered around 4000 Hz, with relatively better thresholds at lower frequencies (speech frequencies) and often some recovery at 8000 Hz. This pattern reflects the cochlear anatomy: the region of the cochlea tuned to 4000 Hz is particularly vulnerable to noise damage.
Normal occupational hearing thresholds: 0–25 dB HL at all frequencies. Mild hearing loss: 26–40 dB HL. Moderate: 41–55 dB HL. Moderately severe: 56–70 dB HL. Severe: 71–90 dB HL.
For STS detection, OSHA compares the average threshold at 2000, 3000, and 4000 Hz in each ear between the current annual audiogram and the baseline. A 10 dB or greater average increase in either ear is a Standard Threshold Shift. The professional supervisor must review and confirm the STS determination before follow-up obligations are triggered.
▶ Bottom line: The 4000 Hz notch is the audiometric signature of noise-induced hearing loss. When an annual audiogram shows a new or deepening notch compared to baseline, it warrants immediate professional supervisor review regardless of whether the STS threshold has been crossed.
When an annual audiogram shows a Standard Threshold Shift — confirmed by the professional supervisor — OSHA 1910.95(g)(8) requires a specific sequence of follow-up actions:
Within 21 days: The employer must provide written notification to the employee informing them of the STS. The notification must be in plain language the employee can understand.
Hearing protection refitting: The employer must refit the employee with hearing protectors providing greater attenuation if their current protectors are determined to be inadequate for their noise exposure. This may involve switching protector types, adjusting fit, or upgrading to a higher-attenuation device.
Retest option (within 30 days): An optional retest within 30 days may be conducted to rule out temporary threshold shift as the cause of the apparent STS. If the retest does not confirm the STS, the employer is not required to use the original finding in recording decisions.
Medical referral if indicated: The professional supervisor may refer the employee for further audiological or medical evaluation if the audiogram pattern suggests a non-noise-related cause (sudden change, asymmetric loss, low-frequency involvement).
OSHA 300 recordability determination: If the confirmed STS also meets the additional criteria of 29 CFR 1904.10 (total hearing level of 25 dB HL or more at 2000, 3000, and 4000 Hz averaged), the case must be entered on the OSHA 300 log within 7 days of the determination.
OSHA permits audiometric testing to be administered by one of the following:
However, the results must be reviewed by a licensed audiologist, otolaryngologist, or physician who serves as the program’s professional supervisor. A CAOHC-certified OHC can conduct the test; they cannot make final clinical determinations about STS findings, baseline revisions, or referrals without professional supervisor oversight.
This distinction — between who conducts the test and who reviews results — is frequently misunderstood and leads to programs where a vendor technician conducts testing and uploads results to a portal with no actual physician or audiologist review. That arrangement is not OSHA-compliant regardless of the technician’s qualifications.
OSHA 1910.95(m) requires that audiometric test records be maintained for the duration of the affected employee’s employment plus 30 years. The record must include: the employee’s name and job classification, the date of the audiogram, the examiner’s name, the date of the last acoustic or exhaustive calibration of the audiometer, the employee’s most recent noise exposure measurement, and the background sound pressure levels in audiometric test rooms.
Records must be available to employees, former employees, and their authorized representatives upon request. They must also be available to OSHA compliance officers during inspections. The 30-year retention period makes digital record-keeping essentially mandatory for practical compliance — paper records held in an employee file folder for three decades face significant attrition risk.
Soundtrace delivers OSHA-compliant audiometric testing at your facility without a sound booth — with professional supervisor review, automated STS detection, and 30-year records retention built in.
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