235 ILCS 5/3-3

A majority of the commission shall constitute a quorum to transact business, but no vacancy shall impair the right of the remaining commissioners to exercise all of the powers of the commission; and every act of a majority of the members of the commission shall be deemed to be the act of the commission. The commission shall have a secretary who shall keep a record of all proceedings, transactions, communications and official acts of the commission and who shall be custodian of all records and perform such other duties as the commission may prescribe.