29 CFR §102.32

Witnesses summoned before the Administrative Law Judge must be paid the same fees and mileage that are paid witnesses in the courts of the United States, and witnesses whose depositions are taken or who testify by videoconference and the officer who transcribes the testimony shall severally be entitled to the same fees as are paid for like services in the courts of the United States, and those fees shall be paid by the party at whose instance the deposition is taken.