Maryland Code, Public Safety § 10-102

(1) the sale, possession, or use of fireworks to or by the federal government or a state or a political subdivision of a state;

(2) the sale, possession, or use of a combustible or explosive preparation to or by an industrial or commercial business for use as a signal or otherwise in the normal course of business;

(3) the possession or use of a fusee, railroad torpedo, rocket, Very signal cartridge, or other signal device that is essential to and is kept and used to promote safety in the operation of a motor vehicle, boat, railroad, or aircraft;

(4) the use of a flare, signal pistol, or other equipment if used as a signal in an athletic contest or for a similar purpose; or

(5) subject to the terms and conditions of a permit issued by the State Fire Marshal under subsection (b) of this section, the sale, possession, or use of an explosive device or preparation with a slow-burning fuse rope to or by a farmer for controlling destructive animals.