Employers running OSHA-compliant hearing conservation programs conduct audiometric screening — not diagnostic audiological evaluations. The distinction matters: screening under 29 CFR 1910.95 creates the legally defensible baseline and annual records that serve as the primary evidence set in workers’ compensation proceedings. Diagnostic testing serves clinical purposes. Understanding both — and when each is appropriate — is essential for EHS professionals managing audiometric programs. According to CDC/NIOSH, approximately 22 million U.S. workers face hazardous noise exposure annually.
What Audiometric Screening Is
Audiometric screening under OSHA 29 CFR 1910.95 measures pure-tone air conduction thresholds at 500, 1000, 2000, 3000, 4000, and 6000 Hz. The purpose is occupational monitoring: establishing a baseline, detecting Standard Threshold Shifts year over year, and generating the audiometric record required for OSHA compliance and workers’ compensation defense.
OSHA screening requirements are specific: testing must be conducted with calibrated audiometers meeting ANSI S3.6 standards, in environments meeting ANSI S3.1-1999 maximum permissible ambient noise levels (MPANLs), with a licensed or certified audiologist or physician serving as professional supervisor who reviews results and makes STS determinations. This creates a legally defensible record — not a clinical diagnosis.
| Parameter | OSHA Audiometric Screening | Diagnostic Audiological Evaluation |
|---|---|---|
| Purpose | Occupational monitoring; STS detection; OSHA compliance | Clinical characterization; diagnosis; medical management |
| Who conducts | Trained technician under audiologist/physician supervision | Licensed audiologist |
| Tests included | Pure-tone air conduction thresholds (500–6000 Hz) | Air and bone conduction, speech testing, immittance, OAEs |
| Setting | ANSI S3.1-compliant sound booth or mobile unit | Audiological clinic or hospital audiology department |
| Output | Threshold audiogram; STS determination; OSHA record | Full audiological report; diagnosis; treatment recommendations |
| OSHA required? | Yes, for workers at/above 85 dBA TWA action level | No; required only when clinical referral is indicated |
What Diagnostic Audiological Testing Is
A full diagnostic audiological evaluation is conducted by a licensed audiologist and goes substantially beyond OSHA screening. It typically includes pure-tone air and bone conduction testing, speech recognition testing (word recognition scores), immittance audiometry (tympanometry and acoustic reflexes), and may include otoacoustic emissions (OAEs) or auditory brainstem response (ABR) testing. The output is a clinical report characterizing the type (sensorineural, conductive, mixed), degree, and audiometric configuration of hearing loss — plus medical recommendations.
Diagnostic testing is not an OSHA requirement. It is a clinical service appropriate when the professional supervisor determines that an employee’s audiogram results require clinical characterization beyond what occupational screening provides.
Key Differences for Employers
In workers’ compensation proceedings, the audiometric record that carries the most weight is the employer’s own OSHA-compliant screening series: the pre-employment baseline, the annual audiograms showing threshold stability or change during employment, and the STS determinations with documented follow-up. A diagnostic evaluation obtained after a claim is filed does not substitute for that longitudinal record.
When to Refer for Diagnostic Evaluation
OSHA 1910.95 Appendix E specifies referral criteria for audiological evaluation. Employers should refer workers when:
- A Standard Threshold Shift is confirmed and the professional supervisor determines referral is appropriate
- The audiogram pattern is atypical — asymmetric loss, low-frequency configuration, or sudden change not consistent with noise exposure history
- The worker reports symptoms beyond threshold change: tinnitus, aural fullness, vertigo, or sudden hearing loss
- A baseline audiogram shows pre-existing loss that warrants clinical characterization before employment in noise-exposed roles
Under OSHA 1910.95, a physician or audiologist serving as Professional Supervisor reviews audiograms and makes all STS determinations and medical referral decisions. This is not a decision for an HR generalist or EHS manager. Soundtrace’s audiology team serves as Professional Supervisor for client programs, reviewing all audiograms and making all STS and referral determinations.
What OSHA Actually Requires
OSHA 29 CFR 1910.95 requires audiometric testing that meets ANSI S3.6 standards, conducted in an environment meeting ANSI S3.1-1999 MPANLs, with a professional supervisor (physician or audiologist) reviewing results and making STS determinations. The standard does not require diagnostic audiological evaluations for all workers — only occupational screening that creates a compliant record with the appropriate clinical oversight.
Frequently Asked Questions
OSHA-Compliant Audiometric Screening with Professional Supervisor Oversight
Soundtrace provides automated audiometric testing meeting ANSI S3.6 and S3.1-1999 standards, with licensed audiologist Professional Supervisor review of all results and STS determinations.
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