The OSHA 300 log and the 1910.95 hearing conservation program are governed by two separate standards with two different criteria — and most employers confuse them. A standard threshold shift (STS) under 1910.95 triggers notification, HPD follow-up, and possible medical referral. But it does not automatically trigger a 29 CFR 1904.10 recordable hearing loss case. According to the CDC, approximately 22 million U.S. workers are exposed to hazardous occupational noise annually — and the gap between an STS and a recordable case is where most employers make the most costly compliance errors. This guide explains the two-standard framework, the recordability criteria, and how to handle the determination correctly.
The Two-Standard Framework
Employers must navigate two separate OSHA standards that interact around occupational hearing loss:
- 29 CFR 1910.95 governs the hearing conservation program — noise monitoring, audiometric testing, STS identification, HPD provision, training, and recordkeeping. An STS under 1910.95 triggers a specific sequence of employer actions regardless of recordability.
- 29 CFR 1904.10 governs the recording of occupational hearing loss on the OSHA 300 Log. It has its own criteria for when a hearing loss case is recordable — criteria that are more restrictive than the STS definition.
Every recordable hearing loss case will involve an STS — but not every STS produces a recordable case. The STS is necessary but not sufficient for 300 Log recordability. See: OSHA 1910.95: complete employer guide.
STS vs. Recordable Case: The Key Difference
| Criterion | 1910.95 STS | 1904.10 Recordable Case |
|---|---|---|
| Threshold shift required | 10 dB average at 2k/3k/4k Hz from baseline | Same STS requirement, PLUS 25 dB total hearing level |
| Work-relatedness required | Not explicitly — STS triggers action regardless | Yes — must be work-related to be recordable |
| Total threshold level check | Not required for STS determination | Must average 25 dB or more above audiometric zero |
| Age correction available | Optional (Appendix F) | Optional (may apply before recordability determination) |
| Triggers employer actions? | Yes: notification, HPD review, referral, baseline revision | Yes: 300 Log entry, 300-A Summary, OSHA reporting if needed |
The Three-Part Recordability Test Under 1904.10
A hearing loss case is recordable on the OSHA 300 Log when all three of these conditions are met:
- Standard Threshold Shift exists: The worker’s average shift at 2,000, 3,000, and 4,000 Hz in either ear meets or exceeds 10 dB compared to the baseline audiogram (after any permissible age correction).
- Total hearing level meets the threshold: The worker’s current audiogram thresholds, averaged at 2,000, 3,000, and 4,000 Hz in the affected ear, are 25 dB or more above audiometric zero (0 dB HL). A worker with a small STS whose absolute thresholds remain below 25 dB HL is not a recordable case.
- Work-relatedness: The hearing loss is work-related — an event or exposure in the work environment either caused or contributed to the loss or significantly aggravated a pre-existing condition. OSHA presumes work-relatedness for hearing loss cases; employers can rebut this presumption with evidence (e.g., pre-employment audiogram showing pre-existing loss, or documented non-occupational cause).
Most young workers have audiometric thresholds well below 25 dB HL at all frequencies. An STS from noise exposure in a worker with excellent baseline hearing (e.g., thresholds of 5–10 dB HL at baseline) may produce current thresholds in the 15–20 dB range — below the recordability threshold even with an STS confirmed. Conversely, a worker with moderate pre-existing hearing loss who has a small additional STS may have current thresholds above 25 dB HL — recordable if work-related.
Age Correction and Recordability
OSHA’s hearing loss recordkeeping rule explicitly allows employers to apply Appendix F age correction before making the recordability determination. If age correction eliminates the STS entirely, the case is not recordable. If age correction reduces the STS but the current threshold average still meets or exceeds 25 dB HL and the case is work-related, the case remains recordable — but with a smaller recorded shift. Document whether age correction was applied, the corrected shift values, and the resulting recordability determination.
How to Record a Hearing Loss Case on the 300 Log
When a case meets all three recordability criteria, it must be recorded on the OSHA 300 Log within 7 calendar days of the employer becoming aware of the recordable case. On the OSHA 300 Log:
- Check the “Hearing Loss” column (column M on the standard 300 Log)
- Enter the worker’s name, job title, date of diagnosis, and a brief description of the case
- Do not check “Days away from work” or “Restricted work” unless those conditions also apply
- Include the case on the OSHA 300-A Annual Summary for the calendar year in which it occurred
Some employers record every STS as a 300 Log entry. Others record none. Neither is correct. The proper approach: calculate the STS under 1910.95, then separately evaluate whether the 25 dB HL total threshold condition is met and whether the case is work-related. Only cases meeting all three criteria should be recorded. See: standard threshold shift: definition, calculation, and action steps.
Retention and Access Requirements
The OSHA 300 Log and 300-A Summary must be retained for 5 years following the end of the calendar year to which they relate. This is separate from the 1910.95(m)(2) requirement to retain audiometric records for the duration of employment. Employers must make 300 Logs available to employees, former employees, and their representatives upon request, and must post the 300-A Summary in the workplace from February 1 through April 30 each year.
For the full audiometric record retention framework and the WC defense implications of record gaps, see: audiometric records security: HIPAA and SOC 2 compliance and workers’ compensation for occupational hearing loss: 50-state guide.
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Get a Free Quote Book a demo →Frequently Asked Questions
No. An STS under 1910.95 is recordable on the OSHA 300 Log only if it is work-related and the employee’s total hearing level averaged at 2,000, 3,000, and 4,000 Hz in the affected ear is 25 dB or more above audiometric zero. An STS in a worker whose thresholds remain below 25 dB HL is not a 300 Log recordable case.
The OSHA 300 Log and 300-A Summary must be retained for 5 years following the calendar year covered. This is separate from the 1910.95(m)(2) requirement to retain audiometric records for the duration of employment.
Yes. OSHA allows age correction to be applied before the 300 Log recordability determination. If age correction eliminates the STS, the case is not recordable. If age correction reduces the STS but the remaining average threshold still meets or exceeds 25 dB HL, the case remains recordable.
An STS under 1910.95 is a 10 dB average shift at 2k/3k/4k Hz that triggers notification, HPD review, and follow-up — regardless of absolute threshold levels. A recordable case under 1904.10 additionally requires that the worker’s total hearing level at those frequencies is 25 dB HL or more above audiometric zero AND the case is work-related. Every recordable case involves an STS, but not every STS produces a recordable case.
The OSHA 300 Log entry must be made within 7 calendar days of the employer becoming aware of the recordable case. For hearing conservation, the employer typically becomes aware when the Professional Supervisor confirms the STS and the recordability evaluation is complete. A delayed entry is itself a citable violation.
Yes. A hearing loss case is recordable only if it is work-related — an event or exposure in the work environment caused or contributed to the loss, or significantly aggravated a pre-existing condition. OSHA presumes work-relatedness for hearing loss cases. Employers can rebut this presumption with a pre-employment audiogram showing pre-existing loss or documented evidence of a non-occupational cause.
Check the Hearing Loss column (column M on the standard 300 Log). Enter the worker’s name, job title, date of diagnosis, and a brief description of the case. Do not check Days Away from Work or Restricted Work unless those conditions also apply. Include the case on the OSHA 300-A Annual Summary for the calendar year in which it occurred.
Yes. The 300-A Annual Summary must be posted in the workplace from February 1 through April 30 each year. It must be signed by a company executive certifying that the information is accurate. Employers must make 300 Logs available to employees, former employees, and their representatives upon request.
- Standard Threshold Shift: Definition, Calculation & Action Steps
- Age Correction in OSHA Audiograms: When and How to Apply Appendix F
- Audiometric Testing for Employers: Complete OSHA Guide
- OSHA Hearing Conservation Program: The Complete Guide
- OSHA 1910.95: The Complete Employer Guide
- Noise-Induced Hearing Loss: The Complete Employer Guide
- HPD Fit Testing: The Complete Employer Guide
- OSHA Hearing Conservation Violations & Penalties: 2026
- Workers’ Compensation for Occupational Hearing Loss: 50-State Guide
- Audiometric Records Security: HIPAA & SOC 2 Compliance