225 ILCS 105/19.2

The Department has the power to subpoena documents, books, records, or other materials and to 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 in civil cases in the courts of this State. The Secretary, the designated hearing officer, and the Department have the power to administer oaths to witnesses at any hearing that the Department is authorized to conduct and any other oaths authorized in any Act administered by the Department.