OSHA STS Employee Notification: What 1910.95(g)(8) Requires and When
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Audiometric Testing·OSHA Compliance·11 min read·Updated March 2026
When an employee’s annual audiogram shows a standard threshold shift — a 10 dB average shift at 2,000, 3,000, and 4,000 Hz compared to their baseline — OSHA requires the employer to take a series of specific follow-up actions, including written notification to the employee within 21 days of the determination. This notification requirement under 1910.95(g)(8) is one of the most frequently overlooked and most commonly cited deficiencies in occupational hearing conservation program inspections. This guide explains exactly when the 21-day clock starts, what the notification must include, how it differs from the 300 Log recordability obligation, and what documentation employers must maintain.
Soundtrace automates STS detection and flags notification obligations through the cloud portal when a professional supervisor confirms an STS determination — giving the program coordinator a clear action queue with the 21-day deadline tracked per employee.
21 days
OSHA deadline for written STS notification to the employee — clock starts from the PS determination date, not the audiogram date
Written
OSHA requires written notification — verbal notification alone does not satisfy 1910.95(g)(8) regardless of circumstances
Per ear
STS in either ear independently triggers notification — unilateral STS has the same notification requirement as bilateral
The Regulatory Text
1910.95(g)(8): “Following the determination of a standard threshold shift, affected employees shall be informed of this fact in writing, within 21 days of the determination. “
The key word: “determination” — not the audiogram date. The clock starts when the professional supervisor makes the STS determination.
The 1910.95(g)(8) notification requirement is triggered by a confirmed STS — a 10 dB or greater average shift in hearing thresholds at 2000, 3000, and 4000 Hz in either ear, compared to the established baseline audiogram. This includes STSs that have been age-corrected per Appendix F and still meet the 10 dB average criterion. A retest that confirms the STS (rather than resolving it) keeps the notification requirement active.
If a retest within 30 days of the original audiogram does not confirm the STS, the notification requirement does not apply to that episode. However, if the retest confirms the STS, the employer must provide written notification within 21 days of the determination that the retest confirmed.
STS Confirmation to Notification: Critical Deadlines
Two parallel obligations run from STS confirmation: the 21-day notification and the 30-day retest window. The retest must be offered and completed within 30 days to be usable.
When the 21-Day Clock Starts — and Why This Matters
The 21-day notification deadline runs from “the determination” — the date the professional supervisor formally identifies the STS, not the date the audiogram was conducted. In practice, this means the clock begins when the PS review is complete and the STS is confirmed.
This distinction creates an operational trap: if the professional supervisor reviews audiograms on a weekly or monthly batch cycle, there may be a significant lag between when the audiogram was conducted and when the STS is actually determined. An audiogram conducted in Week 1 that isn’t reviewed until Week 3 leaves only 0 days to meet the 21-day notification deadline from the audiogram perspective — but the OSHA deadline is actually running from Week 3. The employer still has 21 days from that determination to notify, but the retest window (30 days from the audiogram) may already be closing.
Late PS review can eliminate the retest option
The 30-day retest window runs from the date of the original audiogram, not from the PS determination. If the professional supervisor reviews an audiogram 4 weeks after it was conducted and identifies an STS, the employer may have only days — or zero days — left to conduct a retest before the window closes. Prompt PS review within days of testing is the only way to preserve the full retest window and the full 21-day notification window simultaneously.
What the 1910.95(g)(8) Notification Must Include
OSHA requires that the affected employee be “informed of this fact” — meaning that an STS has been detected. The regulation does not prescribe specific language for the notification, but best practice and the intent of the standard suggest the notification should:
State clearly that the employee’s most recent audiogram shows a Standard Threshold Shift
Identify which ear(s) are affected
Inform the employee that this represents a significant change in their hearing from their baseline audiogram
Indicate what follow-up steps are being taken (HPD refitting, retest offer if applicable, referral if appropriate)
Include a date so the 21-day compliance window can be verified
Notification must be in writing
Verbal notification does not satisfy 1910.95(g)(8). The notification must be in writing. A signed acknowledgment from the employee is not required by the standard but provides additional documentation of compliance. The written notification should be retained as part of the employee’s hearing conservation records for the duration of employment plus 30 years.
STS Notification vs. 300 Log Recordability: Two Separate Analyses
Requirement
STS Notification (1910.95(g)(8))
300 Log Recordability (1904.10)
Trigger
Any confirmed STS (10 dB average at 2-3-4 kHz, age-corrected)
STS confirmed AND total threshold ≥25 dB HL at 2-3-4 kHz average
Deadline
21 days from PS determination of STS
7 days from determination that recording criteria are met
Format
Written notification to employee
Entry on OSHA 300 Log; completion of 301 incident report
Scope
Applies to all confirmed STSs regardless of recordability
Only applies when both STS and 25 dB total threshold criteria are met
Retention
Retained in hearing conservation records (employment + 30 years)
OSHA 300 Log retained 5 years
The Full Post-STS Response
Written notification is one of several actions required after STS confirmation. The complete OSHA 1910.95 post-STS response includes:
1
Written notification within 21 days (1910.95(g)(8))
Inform the employee in writing that their audiogram shows an STS. Identify affected ears. Include date for compliance documentation purposes.
2
HPD refitting and retraining (1910.95(i)(3))
Refit the employee’s hearing protection and retrain them on proper use. If the employee already uses HPDs, upgrade them so attenuation brings exposure to 85 dBA or below — more protective than the 90 dBA target for unaffected workers.
3
Offer retest within 30 days (1910.95(g)(7)(ii))
Offer the employee a retest within 30 days of the original audiogram to confirm or resolve the STS. If retest does not confirm STS, use retest results. If retest confirms, proceed with all follow-up obligations.
4
Evaluate 300 Log recordability (1904.10)
Determine whether the confirmed STS, combined with the total threshold level, meets both criteria for 300 Log recordability. Record within 7 days if both conditions are satisfied and hearing loss is work-related.
5
PLHCP referral if indicated (1910.95(g)(8))
If the professional supervisor determines that a medical referral is appropriate based on the audiometric pattern, the referral must be provided. The PS makes this determination; the employer arranges and pays for the evaluation.
Frequently asked questions
What does OSHA 1910.95(g)(8) require after an STS is confirmed?
OSHA requires written notification to the employee within 21 days of the STS determination, informing them that their audiogram shows a Standard Threshold Shift. This is in addition to HPD refitting, retraining, the 30-day retest offer, 300 Log recordability evaluation, and PLHCP referral if indicated by the PS.
When does the 21-day notification clock start?
The 21-day clock starts from the date the professional supervisor makes the STS determination — not the date of the audiogram. If the PS reviews and confirms the STS 2 weeks after the audiogram was conducted, the 21-day clock starts at that review date.
Does the STS notification apply if the STS is in only one ear?
Yes. OSHA calculates STS per ear independently. A confirmed STS in either ear triggers the 1910.95(g)(8) written notification requirement, regardless of what the other ear shows. There is no exception for unilateral STS.
Is the STS notification the same as the OSHA 300 Log recordability obligation?
No. The STS notification under 1910.95(g)(8) applies to all confirmed STSs. The 300 Log recordability under 1904.10 requires both an STS AND a total threshold of 25 dB HL or worse at the 2-3-4 kHz average. A confirmed STS that is not 300 Log recordable still requires the 21-day written notification.
Does verbal notification satisfy the 1910.95(g)(8) requirement?
No. The regulation requires written notification. Verbal notification alone does not satisfy 1910.95(g)(8). The written notification should be dated, identify the affected ear(s), and be retained in the employee’s hearing conservation records for employment duration plus 30 years.
STS Notification Tracked Per Employee, Per Ear
Soundtrace flags STS determination in the cloud portal the day the professional supervisor completes their review — giving program coordinators the 21-day notification deadline and the 30-day retest window in real time, per employee.
