70 ILCS 3110/9
A majority of the members of the Service shall constitute a quorum and the affirmative vote of a majority of the members present at a meeting of the Authority having a quorum present shall be necessary for any action taken by the Service. The director of the Environmental Protection Agency is a voting member of the Service. No vacancy in the membership of the Service shall impair the right of quorum to exercise all the rights and perform all the duties of the Service. Any action taken by the Service under the provisions of this Act may be authorized by resolution at any regular or special meeting. Each such resolution, other than resolutions promulgating rules and regulations, shall take effect immediately and need not be published or posted. Rules and regulations shall be promulgated under the provisions of the Illinois Administrative Procedure Act, except when necessary for the immediate preservation of the public health and safety and except for emergency provisions required to protect projects of the Service.
70 ILCS 3110/9