Iowa Code § 101A.10: Persons and agencies exempt.

This chapter shall not apply to the transportation and use of explosive materials by the regular military or naval forces of the United States, the duly organized militia of this state, representatives of the director, the state patrol, division of criminal investigation, local police departments, sheriffs departments, and fire departments acting in their official capacity; nor shall this chapter apply to the transportation and use of explosive materials by any peace officer to enforce provisions of this chapter when the peace officer is acting pursuant to such authority, however, other agencies of the state or any of its political subdivisions desiring to purchase, possess, transport, or use explosive materials for construction or other purposes shall be required to obtain user’s permits.