8 Colo. Code Regs. § 1301-1-13
Upon request by any party or intervenor to a proceeding before the Board made at least 14 days prior to hearing, any member of the Board may issue subpoenas involving the party's or intervenor's case, under the seal of the Board. However, a party may not subpoena another party to the action for the production of records. Subpoenas may command the designated witness to appear with or without records and to testify at the specified time and place of the Board hearing. Witness fees and mileage shall be tendered by the party or intervenor procuring the subpoena, as in civil actions in district court. The subpoena shall be served personally no later than 7 days prior to hearing, unless the recipient of the subpoena agrees to waive service and copies of any subpoena and proof of service shall be provided to the opposing party within 48 hours of service.
8 CCR 1301-1-13