Maryland Code, Transportation § 22-402.1

(a) A person may not willfully or intentionally remove, alter, or otherwise render inoperable except for a bona fide repair or replacement, any exhaust emission control device that has been installed by a manufacturer of motor vehicles on a motor vehicle manufactured as a 1968 or later model, if the motor vehicle is factory equipped with this device as required by federal law or by rule or regulation adopted by the Administrator.

(b) A person may not willfully or intentionally remove, alter, or otherwise render inoperable except for a bona fide repair or replacement, any gasoline tank filler inlet device that has been installed by a manufacturer of motor vehicles on a motor vehicle manufactured as a 1968 or later model, if the motor vehicle is factory equipped with this device as required by federal law or by rule or regulation adopted by the Administrator.

(c) A person may not willfully or intentionally remove, alter, or otherwise render inoperable except for a bona fide repair or replacement, any crankcase ventilation device that has been installed by a manufacturer of motor vehicles on a motor vehicle manufactured as a 1968 or later model, if the motor vehicle is factory equipped with this device as required by federal law or by rule or regulation adopted by the Administrator.