"Department", when a particular entity is not specified, means (i) in the case of a function to be performed on or after July 1, 1995 (the effective date of the Department of Natural Resources Act), either the Department of Natural Resources or the Department of Commerce and Economic Opportunity (formerly Department of Commerce and Community Affairs), whichever, in the specific context, is the successor to the Department of Energy and Natural Resources under the Department of Natural Resources Act; or (ii) in the case of a function performed before July 1, 1995, the former Illinois Department of Energy and Natural Resources.
415 ILCS 5/3.180