Ill. Admin. Code tit. 56 § 5300.980
The Department in a matter where it is not a party, may be granted leave by a three-member panel of Commissioners to submit an amicus brief upon a question of law presented by the recommended order and decision. Such leave will be granted upon motion to the Commission and a copy of the motion shall be served on all parties. Such a motion should be made prior to the time any party's exceptions to the recommended order and decision are due, and if granted the Commission shall modify the schedule for submission of exceptions and responses to afford the parties adequate time to respond to the Department's brief. Such a motion by the Department will be granted by the Commission if it is satisfied that the interests of justice would be served thereby.
Ill. Admin. Code tit. 56, § 5300.980
Section 5300.980 renumbered from Section 5300.880 at 9 Ill. Reg. 6207, effective April 24, 1985