820 ILCS 35/3
The application shall be signed by the employer or by a majority of his or her employees in the department of the business in which the controversy or difference exists, or by both parties, and shall contain a concise statement of the grievances complained of, and a promise to continue on in business or at work without any lockout or strike until the decision of said Department, if it shall be made within 3 weeks of the date of filing said application. As soon as may be after the receipt of the application the Department shall cause public notice to be given of the time and place of the hearing thereon; but public notice need not be given when both parties to the controversy join in the application and present therewith a written request that no public notice be given. When such request is made, notice shall be given to the parties interested in such manner as the Department may order, and the Department may, at any stage of the proceedings, cause public notice to be given, notwithstanding such request. The Department may in all cases summon as witnesses any operative or expert in the department of business affected, and any person who keeps the records of wages earned in those departments, or any other person, and examine them under oath, and require the production of books containing the records of wages paid, and such other books and papers as may be deemed necessary to a full and fair investigation of the matter in controversy. The Department may issue subpoenas, and oath may be administered by the Director of the Department or by any authorized officer or employee thereof. If any person, having been served with a subpoena or other process issued by the Department, shall willfully fail or refuse to obey the same, or to answer such questions as may be propounded touching the subject-matter of the inquiry or investigation, the circuit court of the county in which the hearing is being conducted, upon application by the Department, duly attested by the Director thereof, shall issue an attachment for such witness and compel him to appear before the Department and give his or her testimony, or to produce such books and papers as may be lawfully required by the Department; and the court may punish for contempt, as in other cases of refusal to obey the process and order of such court.
820 ILCS 35/3