New Jersey Statutes Title 2C. The New Jersey Code of Criminal Justice 2C § 35-18

Exemption; Burden of Proof. a. If conduct is authorized by the provisions of P.L.1970, c. 226 (C.24:21-1 et seq.), P.L.2009, c. 307 (C.24:6I-1 et al.), or P.L.2015, c. 158 (C.18A:40-12.22 et al.), that authorization shall, subject to the provisions of this section, constitute an exemption from criminal liability under this chapter or chapter 36, and the absence of such authorization shall not be construed to be an element of any offense in this chapter or chapter 36. It is an affirmative defense to any criminal action arising under this chapter or chapter 36 that the defendant is the authorized holder of an appropriate registration, permit, or order form or is otherwise exempted or excepted from criminal liability by virtue of any provision of P.L.1970, c. 226 (C.24:21-1 et seq.), P.L.2009, c. 307 (C.24:6I-1 et al.), or P.L.2015, c. 158 (C.18A:40-12.22 et al.). The affirmative defense established herein shall be proved by the defendant by a preponderance of the evidence. It shall not be necessary for the State to negate any exemption set forth in this act or in any provision of Title 24 of the Revised Statutes in any complaint, information, indictment, or other pleading or in any trial, hearing, or other proceeding under this act.

b. No liability shall be imposed by virtue of this chapter or chapter 36 upon any duly authorized State officer, engaged in the enforcement of any law or municipal ordinance relating to controlled dangerous substances or controlled substance analogs.