OSHA 1904.10 governs when occupational hearing loss must be recorded on the OSHA 300 log. This complete guide covers the work-relatedness standard, the STS threshold, age correction, and common recording mistakes. According to CDC/NIOSH, approximately 22 million U.S. workers are exposed to hazardous occupational noise annually. OSHA 29 CFR 1910.95 governs the audiometric testing and recordkeeping that underlies all of these clinical topics.
Soundtrace audiometric testing is supervised by a licensed audiologist who reviews every audiogram — catching clinical findings that automated algorithms alone may miss and ensuring every compliance and clinical obligation is met.
When Does Occupational Hearing Loss Get Recorded on the OSHA 300 Log?
OSHA 1904.10 requires recording an occupational hearing loss case on the 300 log when two conditions are both met: (1) the employee experienced a work-related Standard Threshold Shift (STS) as defined by 29 CFR 1910.95, AND (2) the employee's overall hearing level (the threshold at which the STS occurred) is 25 dBHL or greater at the STS test frequencies in the affected ear.
Both conditions must be present. An STS alone is not automatically 300-log recordable. An overall hearing level of 25 dBHL or greater alone (without an STS) is not recordable. You need both.
The Work-Relatedness Determination
1904.10 requires that the STS be work-related. OSHA 1904.5 provides the general work-relatedness standard: an event or exposure in the work environment is a presumptive cause of the case unless a specific exception applies. For hearing loss, 1904.10(b)(3) allows the employer to consider the case not work-related if a licensed healthcare professional determines that the hearing loss was not caused by work exposure. This is the Professional Supervisor's clinical role: assessing work-relatedness based on audiogram pattern, noise exposure history, and clinical judgment.
The 25 dBHL Overall Level Threshold
Even when an STS is confirmed, the case is not recordable unless the employee's hearing level in the affected ear is 25 dBHL or greater at the STS test frequencies (2000, 3000, and 4000 Hz) after the shift. A worker who has a confirmed 10 dB STS at 2k/3k/4k Hz but their post-shift average threshold is only 20 dBHL is not recording-required under 1904.10. This provision prevents recording of STSs in workers with excellent overall hearing who have minor threshold fluctuations from baseline.
Age Correction and 300 Log Recordability
OSHA permits age correction of the STS before applying the 25 dBHL overall level threshold for recording purposes. If age correction eliminates the STS entirely, the case is not recordable. If age correction reduces but does not eliminate the STS, the reduced (age-corrected) shift is used for the overall level comparison. Applying age correction consistently in both STS determination and recording decisions avoids inconsistency.
Common 1904.10 Recording Mistakes
| Mistake | Consequence |
|---|---|
| Recording every STS regardless of overall level | Over-recording; inflates OSHA 300 log incidence rates unnecessarily |
| Never recording hearing loss STSs as work-related | Under-recording; citation risk for systemic failure to record work-related cases |
| Making work-relatedness determination without Professional Supervisor input | EHS manager cannot make this clinical determination; PS must be involved |
| Applying age correction to eliminate STSs without PS review | Age correction is an employer option but PS review of the decision is required |
Audiologist-supervised audiometric testing — every audiogram reviewed
Soundtrace audiometric testing is reviewed by a licensed audiologist for clinical significance including STSs, work-relatedness, and referral decisions — ensuring your program meets every 1910.95 and 1904.10 requirement.
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