OSHA Recordable Hearing Loss: STS, 25 dB Rule, and 29 CFR 1904.10

Use the Recordability Tool

Reviewed by an Occupational Medicine physician — board-certified, 15+ years managing the injured and ill worker population, OSHA recordkeeping in clinical practice.

Last updated: April 2026Medically reviewed: April 2026Editorial standards

The Two-Part Test

Under 29 CFR 1904.10, an occupational hearing loss case is recordable only when both of the following conditions are met for the same ear:

The employee has experienced a Standard Threshold Shift (STS) — an average shift of 10 dB or more at 2000, 3000, and 4000 Hz from the audiometric baseline, in either ear.
The employee's total hearing level is 25 dB or more above audiometric zero — averaged across 2000, 3000, and 4000 Hz — in the same ear where the STS occurred.

Either criterion alone is not enough. A young employee can show a 15 dB shift and remain non-recordable if the absolute level is still under 25 dB. A near-retirement employee can sit at 40 dB and remain non-recordable if no shift has occurred from baseline.

Both ears, one ear: The STS can be in either ear, but the 25 dB threshold must be met in the same ear that showed the STS. Do not mix the worst ear for shift with the worst ear for absolute level.

Worked Example #1— Not recordable

A 28-year-old maintenance technician has a baseline audiogram averaging 5 dB at 2/3/4 kHz in the right ear. The annual audiogram now averages 16 dB in the right ear.

Shift: 16 − 5 = 11 dB → STS criterion met.
Absolute level: 16 dB → does not meet the 25 dB criterion.

Result: not recordable. The shift still triggers Hearing Conservation Program obligations under 1910.95 (employee notification within 21 days, retraining, refit of hearing protection), but the case is not entered on the OSHA 300 Log.

Worked Example #2— Recordable

A 54-year-old press operator has a baseline averaging 18 dB at 2/3/4 kHz in the left ear. The annual audiogram now averages 30 dB in the left ear.

Shift: 30 − 18 = 12 dB → STS met.
Absolute level: 30 dB → 25 dB criterion met.

Result: recordable. Enter on the 300 Log under the “Hearing loss” column. Mark the case as an illness, not an injury.

Allowable Adjustments Before Recording

1. Age correction (29 CFR 1904.10(b)(3))

The employer may apply the age correction tables in Appendix F of 29 CFR 1910.95 before determining whether an STS has occurred. Presbycusis-attributable thresholds are subtracted from both the baseline and current audiogram, which often eliminates a shift in older workers. Age correction is permitted but not required, and must be applied consistently.

2. Retest within 30 days

If the initial annual audiogram suggests an STS, the employer may obtain a retest within 30 days and use the retest as the annual audiogram. This protects against transient threshold shifts caused by recent noise exposure, cerumen, or upper respiratory infection. If the retest does not confirm the STS, the case is not recordable.

3. Audiogram review by a licensed professional

A physician, audiologist, or other licensed health care professional reviewing the audiogram may determine that the STS is not work-related or that it has been aggravated by non-occupational noise exposure. If the reviewer documents that the loss is not work-related, the case is not recordable. The reviewer must consider workplace noise exposure history and any non-occupational contributors.

4. Baseline revision

Once an STS is confirmed and persistent, the employer may revise the baseline to the current annual audiogram so that future shifts are measured from the new baseline. Revision does not erase the recordable case — it changes the comparison reference for future audiograms only.

Work-Relatedness in Hearing Loss

Under 29 CFR 1904.5, work-relatedness is presumed if the injury or illness occurred or was aggravated in the work environment. For hearing loss, OSHA further requires the loss to be either caused by, contributed to, or significantly aggravated by occupational noise exposure.

In clinical review, the most common non-occupational contributors that may shift the determination are:

Recreational firearm use, motorcycle riding, or chainsaw operation without hearing protection
Concert or music industry exposure
Ototoxic medications (aminoglycosides, cisplatin, high-dose salicylates, loop diuretics)
Genetic or familial sensorineural hearing loss
Acoustic trauma from a non-work event (explosion, head injury)
Asymmetric loss inconsistent with bilateral noise exposure pattern

Mere presence of a non-occupational contributor does not defeat work-relatedness. The reviewer must weigh whether workplace noise was a contributing factor. If workplace noise contributed in any meaningful way, the case is recordable. The standard is contribution, not sole cause.

Clinical pearl: Noise-induced hearing loss is classically bilateral, symmetric, sensorineural, and shows a notch at 4000 Hz on the audiogram. Asymmetry by more than 15 dB at any frequency, conductive components, or sudden onset should prompt evaluation for a non-noise etiology.

Recording Mechanics

Hearing loss cases have a dedicated check column on the OSHA 300 Log. The case is also classified as an illness rather than an injury. Days away from work are unusual for hearing loss but should be entered if the employee is medically removed from a noise-exposed job pending evaluation.

When marking the column, the most common combinations are:

Other recordable case + Hearing loss — the typical entry. No days away or restriction.
Job transfer + Hearing loss — when the worker is moved out of a high-noise area while additional evaluation occurs.

Tinnitus alone, without a confirmed STS meeting the 25 dB threshold, is not recordable under 1904.10. It may, however, be recordable under the general criteria of 1904.7 if it meets the “significant injury or illness diagnosed by a physician or other licensed health care professional” test.

Common Mistakes

Recording every STS. An STS without the 25 dB absolute threshold is not OSHA recordable. It is a Hearing Conservation Program trigger only.

Mixing ears. The STS ear and the 25 dB ear must be the same. Reviewers commonly take the worst ear for each test and incorrectly call the case recordable.

Forgetting to revise the baseline after recording. Failure to revise causes the same STS to appear in every subsequent annual audiogram, leading to repeat recordkeeping errors.

Skipping age correction without documenting. Employers may apply age correction or not, but must be consistent. Inconsistent application invites OSHA scrutiny of recordkeeping integrity.

Treating audiogram review as automatic exclusion. The reviewing professional must affirmatively determine that the loss is not work-related. A non-decision or a review that simply notes “possible non-occupational contributors” does not meet the standard for excluding the case.