70 ILCS 5/3.3
Should the foregoing provisions respecting the appointment of commissioners representing the area within any municipality of five thousand or more population be invalid when applied to any situation, then as to such situation any such provision shall be deemed to be excised from this act, and the commissioner whose appointment is thus affected shall be appointed at large by the county board, or in the case of a home rule county as defined by Article VII, Section 6 of the Constitution of 1970 by the chief executive officer of the county with the advice and consent of the county governing board, except if the Authority embraces more than one county in which case the commissioners shall be appointed at large by the members of the General Assembly whose legislative districts encompass any portion of the Authority.
70 ILCS 5/3.3