225 ILCS 37/23

(a) A licensed environmental health practitioner in training or an environmental health inspector may perform the duties and functions of environmental health practice under the supervision of a licensed environmental health practitioner or licensed professional engineer. (b) A licensed environmental health practitioner or a licensed professional engineer may serve as a supervisor to any licensed environmental health practitioner in training or environmental health inspector. The supervisor shall fulfill the minimum supervisor requirements, including but not limited to: (1) being available for consultation on a daily basis; (2) reviewing and advising on law enforcement proceedings; and (3) evaluating the practice of environmental health performed by the licensed environmental health practitioner in training or the environmental health inspector. (c) A licensed environmental health practitioner or licensed professional engineer is responsible for assuring that a licensed environmental health practitioner in training or environmental health inspector that he or she is supervising properly engages in the practice of environmental health.