The provisions of this chapter restricting the possession and having control of controlled substances shall not apply to:

(1)  Common carriers or to warehouse operators while engaged in lawfully transporting or storing controlled substances, or to any employee of them acting within the scope of his or her employment;

(2)  Public officers or their employees in the performance of their official duties requiring possession or control of controlled substances;

(3)  Temporary incidental possession by employees or agents of persons lawfully entitled to possession, or by persons whose possession is for the purpose of aiding public officers in performing their official duties, or emergency medical personnel in the performance of their official duties; or

(4)  Persons lawfully in possession or control by reason of a proper order, prescription, license, or registration.