Audio Metric (Hearing) Testing Cont.
- Each employee's annual audiogram will be compared to his/her baseline audiogram by qualified evaluator to determine if a Standard Threshold Shift (STS) has occurred.
- A Standard Threshold Shift is defined by OSHA as a change in hearing threshold relative to the baseline of an average of 10dB or more at 2000, 3000, 4000 Hz either ear.
- In determining if a Standard Threshold Shift has occurred, an allowance can be made for the contribution of aging (presbycusis). The age correction values to be used are found in Appendix F of 1910.95.
- If an annual audiogram indicates that an employee has incurred a Standard Threshold Shift, the person will be scheduled for a retest within 30 days to determine if the threshold shift is persistent.
- The following procedures will be taken if a comparison of the baseline audiogram indicates a persistent standard threshold shift:
- Employees not using hearing protectors will be trained, fitted, and required to use hearing protectors if they are exposed to an 8 hour TWA average sound level of 85 decibels or greater.
- Employees already using hearing protectors will be retrained, refitted, and required to use hearing protectors.
- The (Position designated) will inform the employee, in writing, within 21 days of this determination, of the existence of a permanent Standard Threshold Shift (See Form #2). A copy of the STS letter will also be sent to the employee's supervisor.
- The (Position designated) will counsel the employee on the importance of using hearing protectors and refer the employee for further clinical evaluation if necessary.
- Persistent significant threshold shifts must be entered on the OSHA 200 Log (From 200) if determined to be work related.
- If a subsequent audiometric testing of an employee whose exposure to noise is less than an 8-hour TWA of 90 decibels indicates that a Standard Threshold Shift is not persistent, the (Position designated):
- Shall inform the employee of the new audiometric interpretation.
- Discontinue the required use of hearing protectors for that employee.