70 ILCS 1505/25.9
Sections 25.1 to 25.9, both inclusive, of this Act as now enacted and as may hereafter be amended, shall not be construed as authorizing the Chicago Park District to make any expenditure under this Act except from revenue bonds as above provided or from revenues derived from the operation of parking facilities, nor shall sections 25.1 to 25.9, both inclusive, of this Act as now enacted and as may hereafter be amended, be construed as authorizing the Chicago Park District to engage in any proprietary activity at or with any such parking facilities other than the parking of motor vehicles. However, in cases of national emergency the Chicago Park District may permit the use of such underground garage or garages as bomb shelters.
70 ILCS 1505/25.9