Maryland Code, Agriculture § 5-110

(1) Any carrier while lawfully engaged in transporting a pesticide within the State, if the carrier, upon request, permits the Secretary to copy any record showing the transactions in and movement of any pesticide;

(2) Any public official of the State or the federal government engaged in the performance of his official duty; or

(3) A manufacturer or shipper of a pesticide for experimental use only (i) by or under the supervision of an agency of the State or of the federal government authorized by law to conduct pesticide research, or (ii) by any other person if the pesticide is not sold and if its container shows the manufacturer's name and address and it is plainly and conspicuously marked “for experimental use only -- not to be sold”. However, if a written permit is obtained from the Secretary, the pesticide may be sold for experimental purposes subject to any restriction set forth in the permit.