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The baseline audiogram is the reference audiogram against which future audiograms are compared. Employers must provide baseline audiograms within six months of an employee’s first exposure at or above an 8-hour time weighted average (TWA) of 85 dB. An exception is allowed when the employer uses a mobile test van for audiograms. In these instances, baseline audiograms must be completed within 1 year after an employee’s first exposure to workplace noise at or above a TWA of 85 dB. Employees, however, must be fitted with, issued, and required to wear hearing protectors whenever they are exposed to noise levels above a TWA of 85 dB for any period exceeding 6 months after their first exposure until the baseline audiogram is conducted.
Employees should not be exposed to workplace noise for 14 hours before the baseline test or wear hearing protectors during this time period.