Mo. Rev. Stat. § 191.773: Violators, guilty of infraction.

The following persons shall be guilty of an infraction:

(1) A person who smokes in those areas where smoking is prohibited pursuant to the provisions of sections 191.765 to 191.773 and section 290.145;

(2) A proprietor or other person in charge of a public place or public meeting who permits, causes, suffers or allows a person to smoke in those areas where smoking is prohibited pursuant to sections 191.765 to 191.773 and section 290.145.