When Is Hearing Loss Recordable on an OSHA 300 Log? STS and 25 dB Rules Explained
Picture this. Your safety coordinator stares at a fresh audiogram. The numbers show a shift. Is this OSHA recordable hearing loss? One wrong call means compliance trouble. Get it right, and you protect your team and records. This guide breaks down the rules for OSHA hearing loss recordable cases on the 300 Log.
FORM 300 LOGBOOK is independent software for organizing OSHA 300, 300A, and 301 recordkeeping information. It is not affiliated with, endorsed by, approved by, or operated by OSHA or the U.S. Department of Labor. This article is independent educational guidance based on sources published by OSHA. It is not legal advice, does not replace official OSHA forms, does not submit records to OSHA, and does not guarantee compliance.
Currentness note: Facts draw from 29 CFR 1904.10 and the STS definition in 29 CFR 1910.95(g)(10)(i), as published by OSHA and reviewed against text current as of August 2026.
The Basic Rule for Recordable Hearing Loss
OSHA sets clear triggers under 1904.10(a). Record the case on the OSHA 300 Log if two things happen. First, the employee's audiogram shows a work-related Standard Threshold Shift (STS) in one or both ears. Second, the total hearing level in that ear averages 25 dB or more above audiometric zero at 2000, 3000, and 4000 Hz. Both must align in the same ear or ears.
Miss either, and you skip the log. This keeps occupational hearing loss log entries precise. No STS alone makes it recordable. The 25 dB threshold acts as a gatekeeper.
What Counts as a Standard Threshold Shift?
STS Defined Under 1904.10(b)(1)
STS means a change in hearing threshold. Compare to the baseline audiogram. Look at the average at 2000, 3000, and 4000 Hz. A shift of 10 dB or more in one or both ears qualifies. OSHA pulls this from 29 CFR 1910.95(g)(10)(i).
A 10 dB STS by itself does not trigger recording. Pair it with the 25 dB total level rule. Think hypothetical: baseline average of 10 dB. Current average hits 20 dB. That's a 10 dB STS. But 20 dB total falls short of 25 dB. No log entry.
Which Audiograms Do You Compare?
1904.10(b)(2) Guidelines
Start with the employee's baseline if they have no prior recordable loss. Use the current audiogram against it for STS.
Prior recordable case? Compare to the revised baseline. That audiogram marked the last recordable shift. See our guide on OSHA 300 Log new case or recurrence for details.
For the 25 dB check, always use the current audiogram's average at 2, 3, and 4 kHz against zero. No baseline here.
Age Adjustments: When and How
You may age-adjust the current audiogram for STS only. Use Tables F-1 or F-2 from appendix F of 29 CFR 1910.95. Skip age adjustment for the 25 dB total level test. That one stays raw.
Retests Change the Game
Rules from 1904.10(b)(4)
Retest within 30 days if the first shows potential STS. Retest clears it? No recording needed. Retest confirms? Record within seven calendar days.
Later tests under 1910.95 prove STS not persistent? Erase or line out the entry. Learn more in our how-to-correct-an-osha-300-log-entry post.
Is It Work-Related? Check 1904.5
Apply work-relatedness under 1904.10(b)(5) and (b)(6). Follow 1904.5 rules. A physician or licensed professional says no work link or no significant aggravation by noise? Skip the log.
Treat their input as part of the process. It must align with 1904.5. Dive deeper in how to decide if an injury is work-related for OSHA 300.
Filling the OSHA 300 Log
Recordable case confirmed? Check the hearing loss column on the 300 Log per 1904.10(b)(7). Follow full steps in how to fill out an OSHA 300 Log step-by-step. Link to a 301 Incident Report for details.
FORM 300 LOGBOOK serves as your workspace. Organize the case, classification, and 301 link post-review. It does not read audiograms or replace clinicians.
Hearing Conservation vs. 300 Log Recording
STS triggers 1910.95 duties like follow-ups, even without 25 dB. That's the hearing program. This guide focuses on 1904.10 recording. See OSHA guidance for more.
Your Practical Checklist for 1904.10 STS 25 dB
- 10 dB average shift at 2/3/4 kHz from baseline (or revised)?
- Current audiogram shows 25 dB+ total in same ear(s)?
- Age adjustment only for STS step?
- Work-related per 1904.5?
- Retest within 30 days if needed?
- Hearing loss column checked if yes?
Run this list after every audiogram. Standard threshold shift OSHA 300 decisions stay sharp.
Master these rules. Your OSHA 300 Log reflects reality. Teams hear better. Compliance holds firm. Review audiograms with confidence.