Ill. Admin. Code tit. 56 § 5300.1010
Any party to the proceedings may request an opportunity to submit additional evidence for the record, subsequent to issuance of the Administrative Law Judge's recommended order and decision, by including a written request therefor at the time of filing exceptions or responses as hereinabove provided. Such request shall be supported by a statement specifying in detail the evidence which petitioner proposes to present, its relevance, and the reasons why such evidence was not presented at the hearing. A request to present additional evidence shall be granted by the Commission or a three-member panel only if it determines that substantial justice so requires. In general, such a request will be viewed with disfavor by the Commission.
Ill. Admin. Code tit. 56, § 5300.1010
Section 5300.1010 renumbered from Section 5300.910 at 9 Ill. Reg. 6207, effective April 24, 1985