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A Standard Threshold Shift triggers an employer action checklist. But not every STS is recordable on the OSHA 300 log — and misunderstanding the two-part recordability test, the work-relatedness presumption, or the age-correction option can lead to both under-recording and over-recording. Here’s the complete employer guide to OSHA 300 hearing loss recordability.
Soundtrace’s professional supervisor review process automatically evaluates each STS for recordability under 29 CFR 1904.10 — including the significant threshold test, work-relatedness analysis, and age-correction determination — so employers receive a documented, defensible recording decision for every qualifying case.
OSHA’s hearing loss recordability standard at 29 CFR 1904.10 establishes a two-part test. Both parts must be satisfied for a case to require recording:
Part 1 — Standard Threshold Shift: The employee must experience an STS of 10 dB or more averaged at 2000, 3000, and 4000 Hz in either ear, comparing the current annual audiogram to the established baseline.
Part 2 — Significant Threshold (Total Hearing Level): After accounting for any applicable age correction, the employee’s total hearing level in the affected ear must average 25 dB HL or more at 2000, 3000, and 4000 Hz.
Part 2 is the element most frequently misunderstood by employers and even some hearing conservation service providers. An STS in an employee with excellent baseline hearing may not cross the 25 dB HL total threshold — and is therefore not recordable regardless of the magnitude of the shift.
Example: An employee’s baseline averages 8 dB HL at 2000, 3000, and 4000 Hz (excellent hearing). An annual audiogram shows a 10 dB STS at those frequencies, bringing the total average to 18 dB HL. The STS threshold is met but the total hearing level remains below 25 dB HL — not recordable.
▶ Bottom line: An STS does not automatically create an OSHA 300 entry. The total hearing level test (25 dB HL average) is equally required, and failing to apply it leads to unnecessary recordings that inflate injury rates and trigger unwarranted compliance scrutiny.
The STS definition in 29 CFR 1910.95(g)(10)(i) and in 29 CFR 1904.10 use the same 10 dB average threshold at 2000, 3000, and 4000 Hz. But they operate in different regulatory frameworks with different follow-up obligations.
Under 1910.95, an STS triggers: written employee notification within 21 days, hearing protection refitting, referral for clinical evaluation if indicated, and professional supervisor review. The 1910.95 STS is a health surveillance trigger.
Under 1904.10, an STS that also meets the total hearing level test triggers: an OSHA 300 log entry, a 300-A annual summary entry, and retention in injury and illness records for five years. The 1904.10 determination is a recordkeeping obligation.
These two obligations run in parallel but are separate. An STS under 1910.95 requires follow-up action regardless of whether it meets 1904.10 recordability criteria. An STS that is not recordable under 1904.10 (because total hearing level is below 25 dB HL) still requires the full 1910.95 follow-up protocol.
▶ Bottom line: A non-recordable STS still requires 1910.95 follow-up. The recordability determination affects the OSHA 300 log entry; it does not determine whether employee notification, hearing protection refitting, or professional supervisor review are required.
Calculating the total hearing level for the significant threshold test requires the current annual audiogram thresholds — not the baseline — at 2000, 3000, and 4000 Hz in the affected ear. The calculation:
Total Average Hearing Level = (Threshold at 2000 Hz + Threshold at 3000 Hz + Threshold at 4000 Hz) ÷ 3
If age correction is applied, the age-corrected thresholds are used in this calculation rather than the raw audiogram values. If the resulting average is 25 dB HL or greater, the significant threshold test is met and — assuming the STS test is also met — the case is recordable.
| Scenario | STS Met? | Total HL ≥25 dB? | Recordable? |
|---|---|---|---|
| Baseline 8 dB avg; current 18 dB avg | Yes (10 dB shift) | No (18 dB) | No |
| Baseline 15 dB avg; current 27 dB avg | Yes (12 dB shift) | Yes (27 dB) | Yes |
| Baseline 20 dB avg; current 28 dB avg | No (8 dB shift) | Yes (28 dB) | No |
| Baseline 5 dB avg; current 30 dB avg (age-corrected: 22 dB) | Yes (raw) / No (age-corrected) | No (22 dB) | No (if age correction applied) |
▶ Bottom line: Walking through both parts of the test explicitly for every STS case — and documenting the calculation — protects the employer from both under-recording (missed recordable cases) and over-recording (unnecessary 300 entries).
Under 29 CFR 1904.5, a work relationship presumption applies to any injury or illness where an event or exposure in the work environment caused or contributed to the condition. For hearing loss, this presumption is strong: if the employee is exposed to noise at or above OSHA’s action level and develops measurable hearing deterioration, work exposure is presumed causal unless there is compelling evidence to the contrary.
OSHA recognizes a limited set of circumstances that can rebut the work-relatedness presumption:
OSHA’s guidance is explicit that rebuttal requires strong evidence — not just a plausible alternative explanation. An employer who routinely lists “non-occupational cause” without documented clinical support is creating a recordkeeping manipulation liability, not a compliant program.
▶ Bottom line: Work-relatedness is presumed for noise-exposed employees with measurable hearing deterioration. Rebuttal requires documented clinical determination by the professional supervisor, not an administrative decision by the employer.
OSHA permits — but does not require — employers to apply age correction when calculating whether an STS meets recordability criteria. The age correction tables in OSHA Appendix F to 29 CFR 1910.95 provide age-based expected threshold changes that can be subtracted from the measured STS to isolate the portion attributable to noise rather than presbycusis (age-related hearing loss).
If age correction reduces the STS below 10 dB after the adjustment, the recordability threshold is not met and the case is not required to be recorded. If age correction reduces the total hearing level below 25 dB HL, recordability is similarly avoided.
Key practical points on age correction:
Whether to apply age correction should be a documented program policy decision made with the professional supervisor — not an ad hoc determination. A consistent, documented policy on age correction is significantly more defensible to OSHA than case-by-case decisions that appear to correlate with whether the case would otherwise be recordable.
▶ Bottom line: Age correction is a legitimate tool if applied consistently with a documented rationale. Applied inconsistently or without documentation, it looks like recordkeeping manipulation — which carries far greater liability than the 300 log entry itself.
When an annual audiogram shows an STS, OSHA 1910.95(g)(7)(ii) permits retest within 30 days. If the retest does not confirm the STS, the employer is not required to consider the temporary STS in recording decisions. This retest option exists because temporary threshold shifts from pre-test noise exposure can mimic genuine permanent hearing change.
However, several conditions must be met for the retest to be valid for recordability purposes:
A common program management error is allowing more than 30 days to pass before completing a retest, then attempting to use the retest result to avoid recording. OSHA considers an STS that is not retested within 30 days to be persistent — and the recordability analysis should be completed and the log entry made (if applicable) before that window closes.
▶ Bottom line: The retest window is 30 days from the original STS audiogram — not 30 days from when the employer gets around to reviewing results. Missing the window forfeits the retest option and requires completing the recordability analysis on the original STS data.
Under 29 CFR 1904.29(b)(3), recordable cases must be entered on the OSHA 300 log within seven calendar days of receiving information that a recordable case has occurred. For hearing loss, this seven-day clock starts when the employer (or the reviewing professional) determines the case meets recordability criteria — not when the audiometric test was performed.
Required entries on the OSHA Form 300:
Hearing loss entries use Column M7 (hearing loss) on the OSHA 300 form. This column was added in the 2002 recordkeeping rule specifically for hearing loss cases and is separate from the illness/injury classification checkboxes.
▶ Bottom line: Seven calendar days from the recordability determination — not from the audiogram date. A systematic workflow that routes STS cases to professional supervisor review and completes the recordability analysis promptly prevents late entries.
Under 29 CFR 1904.29(b)(6)-(7), certain cases qualify as privacy cases where the employee’s name is withheld from the 300 log to protect medical privacy. Hearing loss cases can be designated as privacy cases, in which case the employer enters “privacy case” in the name column rather than the employee’s name.
OSHA’s list of case types that may be treated as privacy cases includes “other illnesses, if the employee independently and voluntarily requests that his or her name not be entered on the log.” Hearing loss, as an illness rather than an injury, can fall under this provision if the employee makes a voluntary request.
Employers who designate privacy cases must maintain a separate, confidential list of employee names and case numbers that is kept away from the public-facing 300 log. This list must be available to government representatives and to employees or authorized employee representatives upon request.
Soundtrace’s professional supervisor review process evaluates every STS for 1904.10 recordability — applying the two-part test, documenting the rationale, and generating a defensible recording decision within the OSHA deadline window.
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