(2) Should any port district under authority of subsection (1) of this section after August 20, 1957, construct, maintain and operate a hospital or hospital facilities and levy a tax for any indebtedness or other expense incurred therefor, all taxable property in the port district and also within a health district then operating hospital facilities shall be exempt from all taxes levied by a port district for such hospital purposes. [Formerly 441.505; 2003 c.802 §115]