420 ILCS 40/18
The Agency shall hold public hearings, receive pertinent and relevant proof from any party in interest who appears before the Agency , make findings of facts and determinations, all with respect to the violations of the provisions of this Act or codes, rules, regulations or orders issued pursuant thereto. The Department of Nuclear Safety shall, within one year of September 7, 1990 (the effective date of Public Act 86-1341) , adopt rules which prescribe the standards used by the Department in determining when amendments to pleadings shall be allowed to join or dismiss any party, or to delete, modify or add allegations or defenses before the completion of an administrative hearing. The Agency shall allow only attorneys licensed and registered to practice in this State to appear before it in administrative hearings, except that a natural person may appear on his or her own behalf.
420 ILCS 40/18