89B.6  Liability of state or political subdivision.
  The state or any of its political subdivisions is not liable for damages in any claim pursuant to chapter 669 or chapter 670 based upon an act or omission of an employee of the state or political subdivision when the employee exercised due care in the execution of this chapter or a rule adopted under this chapter. Any duty created in this chapter is a duty to the public generally and not to any person or group of persons.
84 Acts, ch 1085, §6
C85, §455D.6
C87, §89B.6