820 ILCS 35/6b
Whenever there shall exist a strike or a lockout, wherein, in the judgment of the Department of Labor, the general public shall appear likely to suffer injury or inconvenience with respect to food, fuel or light, or the means of communication or transportation, or in any other respect, and neither party to such strike or lockout consents to the submission of the controversy to the Department, the Department, after first having made due effort to effect a settlement thereof by conciliatory means, and such effort having failed, may proceed of its own motion to make an investigation of all facts bearing upon such strike or lockout and make public its findings, with such recommendations to the parties involved as in its judgment will contribute to a fair and equitable settlement of the differences. In the prosecution of such inquiry the Department may issue subpoenas and compel the attendance and testimony of witnesses as in other cases.
820 ILCS 35/6b