Md. Code, Environment § 7–249

(a) A person may not transport any controlled hazardous substance from any source in this State or to any controlled hazardous substance facility in this State unless:

(1) The person holds a hauler certificate; and

(2) A vehicle certificate has been issued for the transporting vehicle.

(b) This section does not apply to the transportation of any controlled hazardous substance that is:

(1) Used for residential purposes; or

(2) Regulated by the State Department of Agriculture.