a) Basic Requirement

If an employee's hearing test (audiogram) reveals that the employee has experienced a work-related Standard Threshold Shift (STS) in hearing in one or both ears, and the employee's total hearing level is 25 dB or more above audiometric zero (averaged at 2000, 3000 and 4000 Hz) in the same ear or ears as the STS, record the case on the OSHA 300 Log.

b) Implementation

1. 1) An STS is defined in the occupational noise exposure standard (29 CFR 1910.95(g)(10)(i)) as a change in hearing threshold, relative to the baseline audiogram for that employee, of an average of 10 dB or more at 2000, 3000 and 4000 Hz in one or both ears.

2. 2) Evaluating the Current Audiogram to Determine Whether an Employee has an STS and a 25-dB Hearing Level

   1. A) STS. If the employee has never previously experienced a recordable hearing loss, compare the employee's current audiogram with that employee's baseline audiogram. If the employee has previously experienced a recordable hearing loss, compare the employee's current audiogram with the employee's revised baseline audiogram (the audiogram reflecting the employee's previous recordable hearing loss case).
   2. B) 25-dB Loss. Audiometric test results reflect the employee's overall hearing ability in comparison to audiometric zero. Therefore, using the employee's current audiogram, you must use the average hearing level at 2000, 3000 and 4000 Hz to determine whether the employee's total hearing level is 25 dB or more.
3. 3) When determining whether an STS has occurred, adjust the employee's current audiogram results by using Table F-1 or F-2, as appropriate, in Appendix F of 29 CFR 1910.95. Do not use an age adjustment when determining whether the employee's total hearing level is 25 dB or more above audiometric zero.
4. 4) If the employee's hearing is retested within 30 days of the first test, and the retest does not confirm the recordable STS, the employer is not required to record the hearing loss case on the OSHA 300 Log. If the retest confirms the recordable STS, record the hearing loss illness within 7 calendar days after the retest. If subsequent audiometric testing performed under the testing requirements of the 29 CFR 1910.95 noise standard indicates that an STS is not persistent, you may erase or line-out the recorded entry.
5. 5) In determining whether a hearing loss case is work-related, use Section 350.270 to determine if the hearing loss is work-related. If an event or exposure in the work environment either caused or contributed to the hearing loss, or significantly aggravated a pre-existing hearing loss, consider the case to be work-related.
6. 6) If a physician or other licensed health care professional determines that the hearing loss is not work-related or has not been significantly aggravated by occupational noise exposure, the employer is not required to consider the case work-related or to record the case on the OSHA 300 Log.
7. 7) When entering a recordable hearing loss case on the OSHA 300 Log, check the 300 Log column for hearing loss.