Mo. Rev. Stat. § 292.070
Current with changes from the 2023 Legislative Session
In all such establishments the main doors, both inside and outside, shall open outwardly, when the director, in writing, so directs; and no outside or inside door of any building wherein labor is employed shall be so locked, bolted or otherwise fastened during the hours of labor as to prevent egress.
§ 292.070, RSMo
RSMo 1939 § 10187