Ohio Rev. Code Ann. § 4121.16

Each witness who appears before the bureau of workers' compensation by its order shall receive for the witness's attendance the fees and mileage provided for under section 119.094 of the Revised Code, which shall be paid from the state insurance fund on the approval of the administrator of workers' compensation. No witnesses subpoenaed at the instance of the parties other than the bureau is entitled to compensation from the state for attendance or travel unless the bureau certifies that the witness's testimony was material to the matter investigated.