OSHA 300 Log recordability for occupational hearing loss is one of the most consistently misunderstood recording requirements in general industry. The dual-criteria test under 29 CFR 1904.10 — requiring both an STS and a total threshold meeting a minimum level — trips up even experienced safety managers. Getting it wrong in either direction is a problem: under-recording exposes you to citation and penalty; over-recording inflates your injury and illness rates unnecessarily. This guide explains both the mechanics of the test and the practical workflow for making correct recording decisions.
Soundtrace automates 1904.10 recordability analysis alongside STS calculations — flagging cases where both criteria are met and generating the documentation trail for OSHA recordkeeping compliance.
A work-related hearing loss case is recordable on the 300 Log when BOTH conditions are present: (1) an STS (10+ dB average shift at 2000, 3000, 4000 Hz per ear) AND (2) the total hearing level in that ear is 25 dB HL or worse at the 2-3-4 kHz average after the shift. Both must be met. Either alone is insufficient.
The OSHA 1904.10 Standard
29 CFR 1904.10 covers recording criteria for cases involving occupational hearing loss. It applies to employers required to keep OSHA records (most employers with 10+ employees not in a specifically exempted industry). The standard works in conjunction with 1910.95 audiometric testing requirements — the annual audiogram is the mechanism that generates the data needed for the 1904.10 recordability analysis.
The key feature of 1904.10 is the two-condition structure: an STS alone does not create a recordable case. Both the shift condition (STS) and the total level condition (25 dB HL average) must be independently satisfied.
Condition 1: The STS (Shift Test)
The first recordability condition is the existence of a Standard Threshold Shift: a 10 dB or greater average shift in hearing thresholds at 2000, 3000, and 4000 Hz in either ear, compared to the baseline audiogram. This is the same STS definition used in 29 CFR 1910.95(g)(10). The shift is calculated per ear: the average of the threshold changes at 2000, 3000, and 4000 Hz must be ≥10 dB in at least one ear.
The STS for recordability purposes may be age-corrected. If the employer applies age correction values from Appendix F and the corrected shift falls below 10 dB, the STS condition is not satisfied and the case is not recordable.
Condition 2: The Total Threshold Level Test
The second condition is that the worker’s total hearing level in the affected ear — after the shift is applied — must be 25 dB HL or worse at the 2-3-4 kHz average. This is the worker’s current absolute hearing level at those frequencies, not the size of the shift.
A worker who starts with very good hearing (baseline of 5 dB HL average at 2-3-4 kHz) and has a 10 dB STS now has a total level of 15 dB HL. That is still better than 25 dB HL, so the case is not recordable even though the STS criterion is technically met. The total level test prevents recording cases where workers have measurable shifts but still have essentially normal hearing.
Recording every STS as a 300 Log case without applying the total threshold test inflates your OSHA injury and illness rate unnecessarily. Many workers — particularly younger workers with good baseline hearing — can experience a 10 dB STS and still have total hearing levels below 25 dB HL. These cases are not recordable and should not be logged.
Work-Relatedness Requirement
Even where both conditions are met, the case is only recordable if the hearing loss is work-related under 1904.5. For most employees who work in noisy environments, work-relatedness is presumed under 1904.5’s general rule: if the work environment caused or contributed to the condition, or significantly aggravated a pre-existing condition, it is work-related.
The professional supervisor (physician or audiologist) reviewing the audiogram makes the work-relatedness determination. They may find that a particular STS is more likely attributable to non-occupational causes — aging, recreational noise, otologic disease — in which case the case may not be work-related and need not be recorded even if both numeric criteria are met.
Age Correction and Recordability
OSHA 1904.10(b)(2) explicitly permits employers to use age correction in the recordability analysis. The age correction values come from OSHA Appendix F to 1910.95 and represent the expected shift in hearing thresholds attributable to aging rather than noise exposure. Subtracting these values from the observed shift produces an age-corrected STS that reflects only the non-aging component of the threshold change.
If the age-corrected STS falls below 10 dB, the STS condition is not met and the case is not recordable regardless of the total threshold level. Age correction is permissive — employers may use it but are not required to. However, applying it consistently and documenting the calculation is essential if it is used.
The Retest Option
Under 1904.10(b)(3), if the employee’s STS is confirmed by a retest conducted within 30 days of the original audiogram, the employer must use the retest results for recordability evaluation. If the retest does not confirm the STS, the employer is not required to record the case.
The employer must offer the retest — it is not optional for the employer to skip. But the employee may decline. The retest is conducted after 14 hours of quiet, using the same audiometric equipment and procedures as the original test. If the retest confirms STS, recordability analysis proceeds from the retest results.
Practical Recording Workflow: Step by Step
Frequently asked questions
Automated 300 Log Recordability Analysis. Every Audiogram.
Soundtrace runs the 1904.10 two-condition test automatically after every professional supervisor review — flagging recordable cases, documenting the analysis, and generating the compliance record your OSHA 300 Log requires.
Get a Free Quote- Standard Threshold Shift: OSHA Definition and Required Actions
- STS, 300 Log, and OSHA Recordkeeping: The Complete Guide
- Non-Work-Related Hearing Loss: 300 Log Determinations
- OSHA Appendix F: Age Correction in STS Calculations
- What Is an Audiogram? How to Read Occupational Hearing Tests