225 ILCS 410/4-12

The Department shall have power to subpoena and bring before it any person in this State 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 procedure in civil cases in courts of this State. The Secretary, any hearing officer appointed by the Secretary, and any member of the Board shall each have power to administer oaths to witnesses at any hearing which the Department is authorized by law to conduct, and any other oaths required or authorized in any Act administered by the Department.