(1) A person making a retail sale of a finished drug product containing any quantity of dextromethorphan must require and obtain proof of age from the purchaser before completing the sale, unless from the purchaser's outward appearance the person making the sale would reasonably presume the purchaser to be twenty-five years of age or older.

(2) It is unlawful for any:

(a) Commercial entity to knowingly or willfully sell or trade a finished drug product containing any quantity of dextromethorphan to a person less than eighteen years of age; or

(b) Person who is less than eighteen years of age to purchase a finished drug product containing any quantity of dextromethorphan.

(3) Subsection (2)(a) and (b) of this section do [does] not apply if an individual under eighteen years of age:

(a) Supplies proof at the time of sale that such individual is actively enrolled in the military and presents a valid military identification card; or

(b) Supplies proof of emancipation.

(4)(a) Any manufacturer, distributor, or retailer whose employee or representative, during the course of the employee's or representative's employment or association with that manufacturer, distributor, or retailer sells or trades dextromethorphan in violation of subsection (2)(a) of this section must be given a written warning by a law enforcement agency for the first offense. For any subsequent offense, the manufacturer, distributor, or retailer is guilty of a class 1 civil infraction as provided in RCW 7.80.120, except for any manufacturer, distributor, or retailer who demonstrates a good faith effort to comply with the requirements of this chapter.

(b) Any employee or representative of a manufacturer, distributor, or retailer who, during the course of the employee's or representative's employment or association with that manufacturer, distributor, or retailer sells or trades dextromethorphan in violation of subsection (2)(a) of this section must be given a written warning by a law enforcement agency for the first offense. For any subsequent offense, the employee or representative is guilty of a class 1 civil infraction as provided in RCW 7.80.120.

(c) Any person who purchases dextromethorphan in violation of subsection (2)(b) of this section must be given a written warning by a law enforcement agency for the first offense. For any subsequent offense, the person is guilty of a class 1 civil infraction as provided in RCW 7.80.120.