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When audiometric testing reveals that an employee has experienced a standard threshold shift, OSHA 1910.95(g)(8) requires the employer to act — and act on a specific timeline. Within 21 days of determining that an STS has occurred, the employer must notify the employee in writing. This notification is not optional, is not satisfied by a verbal conversation, and is not the same as a general audiogram results letter. It triggers a specific set of follow-up obligations that many employers either don’t fully understand or don’t execute completely. This guide explains the notification requirement, when the clock starts, what the letter must accomplish, and what must happen next.
Soundtrace generates STS notifications automatically through the cloud portal when a professional supervisor confirms an STS, and tracks the 21-day clock against each confirmed finding across the enrolled workforce.
29 CFR 1910.95(g)(8): “Following the determination that a standard threshold shift has occurred, affected employees shall be notified in writing within 21 days.”
The 1910.95(g)(8) notification is triggered by a determination that an STS has occurred — not simply by an initial audiogram result that shows apparent threshold shift. This distinction matters because 1910.95(g)(7) provides an opportunity for retest before the STS is considered confirmed. The full sequence:
The determination typically requires professional supervisor review. In a cloud-based audiometric program, the PS reviews the result, confirms the STS, and the determination is recorded in the system — which is when the notification obligation is triggered.
The clock runs from the determination of STS, not from the audiogram date. This is an important distinction for programs with a PS review step between the audiogram and the determination. In practice:
Employers who delay PS review — allowing audiograms to accumulate before a periodic review cycle — risk missing the 21-day notification window. If 90 audiograms are reviewed in a batch once per quarter, an STS that occurred in week one of the quarter may already have a late notification by the time the batch review is complete. Best practice is continuous or near-continuous PS review as audiograms are completed.
OSHA 1910.95(g)(8) does not prescribe specific letter content beyond requiring that the employee be informed of the STS determination. OSHA guidance and professional consensus indicate that a compliant, useful notification letter should include:
If the employee’s primary language is not English, the STS notification letter should be provided in the employee’s language. An English-language letter sent to an employee who cannot read English does not effectively communicate the STS finding and may not satisfy the “informed” standard implied by 1910.95(g)(8). This is consistent with OSHA’s language accessibility expectations throughout the hearing conservation standard.
The notification letter does not stand alone. 1910.95(g)(8) requires the employer to take three specific follow-up actions after an STS determination, in addition to the written notification:
Within 21 days of the STS determination, the employee must be fitted or refitted with hearing protectors. For an employee who was already enrolled in the HCP and wearing HPDs, this means ensuring their current device still fits adequately and provides sufficient attenuation — not simply confirming they have an HPD. For a worker whose noise exposure is above the action level and whose post-STS HPD must now attenuate exposure to 85 dBA or below (per 1910.95(i)(3)), this may require upgrading to a higher-attenuation device.
The employee must be retrained on the use and care of hearing protectors if they were not previously trained. In practice, since all HCP-enrolled employees receive annual training that covers HPD use and care, the question is whether that training was adequate given the STS. An employee who developed an STS despite wearing HPDs may have been wearing them incorrectly — making individualized retraining, not just a note in the file, the appropriate response.
If the professional supervisor determines that the employee needs further evaluation by a physician or audiologist, the employer must refer the employee to the appropriate PLHCP. This referral is not automatic for every STS — it is the PS’s judgment call. But it is required when the PS determines it is clinically indicated, and the employer must facilitate and document the referral.
OSHA 1910.95(g)(7)(ii) provides that if the annual audiogram shows an STS, the employer may retest the employee within 21 days of the audiogram. If the retest does not show STS, the employer is not required to regard the initial result as a confirmed STS for purposes of the notification and follow-up obligations.
This creates a practical decision point: should the employer retest before notifying? The answer depends on program design. Many programs notify and initiate follow-up based on the initial result, then update the notification if the retest reverses the finding. This approach avoids the risk of a 21-day notification violation if the retest is delayed. Other programs retest first and notify only if the retest confirms the STS, taking the position that the determination has not been made until the retest is reviewed.
▶ Either approach is defensible. What is not defensible is using the retest option as a reason to delay all follow-up indefinitely — particularly HPD refitting and retraining, which should occur regardless of whether the STS is ultimately confirmed.
A copy of the STS notification letter, along with documentation of when it was sent and how (mail, in-person, electronic), should be retained in the employee’s audiometric record. Under OSHA 1910.1020, audiometric records must be retained for the duration of employment plus 30 years. The notification documentation is part of this record.
Follow-up actions should also be documented: the date of HPD fitting or refitting, the type of HPD provided or confirmed, retraining completion, and any PLHCP referral made. An OSHA compliance officer reviewing an STS case will ask for the notification date, the follow-up action dates, and the documentation of each.
The same language accessibility principles that apply to annual training under 1910.95(k) apply to STS notifications. An employee who cannot read English is not effectively informed by an English-language letter. For Spanish-speaking or other LEP workers, the notification should be provided in their language. The follow-up conversation about HPD fitting and retraining should also be conducted in a language the employee understands.
Soundtrace generates STS notification letters automatically when the professional supervisor confirms an STS finding, and tracks the 21-day clock and follow-up completion status for every case in the cloud portal.
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