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OSHA allows up to 6 months to complete a new employee’s baseline audiogram — but waiting carries significant legal and financial risk. Hearing loss claims can be filed after just 90 days of noise exposure, and without a pre-exposure baseline, you cannot defend against the claim. This article explains why prompt baseline testing protects both employees and employers, and how to build it into onboarding.
Soundtrace makes same-day baseline audiogram testing practical for industrial facilities — in-house testing with no van scheduling, no clinic trips, and a 6-to-8-minute test that fits into any onboarding workflow.
The OSHA 6-month window for baseline testing is a regulatory minimum, not a recommended practice. Delaying baseline testing creates a liability gap that workers’ compensation attorneys know how to exploit — and that no level of hearing protection can retroactively close.
A baseline audiogram is a reference measurement of an employee’s hearing thresholds before — or as early as possible after — beginning work in a noise-exposed environment. OSHA 1910.95(g)(5) requires: baseline audiograms completed within 6 months of first exposure at or above 85 dBA TWA (1 year if mobile testing is the primary method); employees protected by hearing protection during the period between initial exposure and baseline completion; and baseline preceded by at least 14 hours of quiet or continuous hearing protection use.
▶ Bottom line: The 6-month window is the outer limit, not the target. The longer baseline testing is delayed, the more hearing change can occur before a reference measurement exists.
Consider this scenario: a new production worker begins in a 95 dBA area on Monday. Their baseline audiogram is completed at 5 months and 3 weeks — just within the OSHA window. At their 12-month annual audiogram, an STS is identified. The worker’s attorney argues that the shift occurred during the 5-month delay period, before the “baseline” was set. The employer has no pre-exposure reference point to refute this claim. Same scenario with day-one baseline testing: the employer has a documented pre-exposure hearing status and can defend that current noise controls were in place from day one.
▶ Bottom line: An early baseline audiogram is an evidentiary document. It is the foundation of your ability to attribute hearing threshold changes to specific time periods and exposure events.
Workers’ compensation statutes in most states allow hearing loss claims to be filed after exposure periods as short as 60–90 days. A new hire who develops a measurable threshold shift during the baseline delay period may have a compensable claim against your facility for exposure that occurred before you had a reference measurement. Without a pre-exposure baseline, the employer bears the burden of proving that claimed hearing loss did not occur at their facility.
| Scenario | Baseline Timing | Employer’s Liability Position |
|---|---|---|
| Claim filed after 90 days of exposure | No baseline completed yet | No reference point; full exposure period is undefended |
| Claim filed at 12 months | Baseline completed at 5 months | 5-month gap in pre-baseline exposure undefended |
| Claim filed at 12 months | Baseline completed at day 3 | Full employment period documented; strong defense position |
A valid baseline requires: testing after at least 14 hours of hearing protector use or quiet (to eliminate TTS); testing in an environment meeting ANSI S3.1 permissible background noise levels; a calibrated audiometer meeting ANSI S3.6; and professional supervision. A baseline conducted in excessive ambient noise, with an out-of-calibration audiometer, or without adequate quiet time will produce artificially elevated thresholds — making future STS detection more difficult and creating legal exposure if the baseline is challenged.
▶ Bottom line: A weak baseline audiogram can be worse than no baseline at all — it can obscure real hearing changes and fail under legal scrutiny. Quality matters as much as timing.
(1) Day 1 — hearing hazard notification: new hire informed of noise exposure levels; hearing protection worn from first hour in the facility. (2) Day 1 or 2 — 14-hour quiet period: employee briefed to wear hearing protection for 14 hours before testing, or to avoid noise exposure overnight. (3) Day 2 or 3 — baseline audiogram: 6-to-8-minute automated audiogram; results reviewed; record stored. (4) Ongoing: annual audiogram cycle anchored to this baseline. With in-house audiometric testing, there is no operational reason to delay baseline testing past the first week of employment.
OSHA 1910.95(g)(5)(i) allows 6 months from first exposure at or above 85 dBA TWA, or 1 year if using a mobile audiometric testing van. Delaying the full 6 months creates a liability gap for workers’ compensation claims filed during the baseline delay period.
Without a pre-exposure baseline, the employer has no objective reference point to contest claims about when hearing loss began. Courts may attribute any threshold shift during the delay period to workplace exposure.
OSHA 1910.95(g)(5)(ii) requires at least 14 hours of quiet before baseline testing — or continuous hearing protection use for 14 hours as an alternative. The quiet period eliminates TTS so the baseline reflects true permanent thresholds.
Soundtrace’s in-house audiometers make baseline testing a 6-to-8-minute onboarding step with no scheduling required.
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