225 ILCS 95/22.5

The Department shall have power to subpoena and bring before it any person and to take testimony either orally or by deposition or both, with the same fees and mileage and in the same manner as prescribed by law in judicial proceedings in civil cases in circuit courts of this State. The Secretary, the designated hearing officer, and any member of the Board designated by the Secretary shall each have power to administer oaths to witnesses at any hearing which the Department is authorized to conduct under this Act and any other oaths required or authorized to be administered by the Department under this Act.