92 Ill. Adm. Code 14.1155
Formal Participation
Section 14.1155 Formal
Participation
Any person may file an application for leave to intervene in
a proceeding, which application shall show a statutory right or a substantial
interest in the proceeding. A person permitted to intervene in a proceeding
thereby becomes a party to the proceeding for all purposes. No decision
granting or denying intervention shall be deemed to constitute an expression of
the Division with respect to the substantive right of the intervenor.