Ill. Admin. Code tit. 62, § 100.40
a) Applications for Rule-making
Applications shall be in writing and shall contain:
b) Complaints
Complaints shall be by the Department, shall be in writing and shall contain:
c) Petitions
Petitions shall be in writing and shall contain:
d) Intervening Petitions
1) Any person may file a petition requesting leave to intervene in any matter already before the Board. Intervening petitions shall contain:
e) Amendments or Supplements
Amendments of, or supplements to, complaints, petitions, or applications may be filed setting forth matters which have arisen before or after the institution of any proceeding. Amendments or supplements may be made at any time before or after a final decision on the merits either to approve the application or sustain the claim intended to be brought or to make or assert a defense or to conform the pleadings to the proofs upon terms as to continuance that may be just and reasonable.
f) Notice as to Duration of Hearing
If at the time a petition, application or complaint is filed with the Board, the Board determines or is advised by the filing party that the probable duration of the presentation of the matter in entirety may exceed one (1) day, the Board whenever possible, shall set the hearing for consecutive days.
g) Adjudicatory Proceedings – Answers
Answers to formal complaints or petitions shall be filed with the Board within ten (10) days after the day on which such complaint or petition is served upon the adverse party, unless otherwise ordered. If any adverse party fails to file an answer, issue as to such adverse party will be considered joined. Answers shall contain an explicit admission, denial, or appropriate response to each allegation of the pleading to which they relate and a concise statement of the nature of the defense.