Every employer engaged in carrying on any process or manufacture or labor referred to in section 292.310, shall provide, separate and apart from the workshop in which such employees are engaged, a dressing room and lavatory for the use of such employees who are exposed to poisonous or injurious dusts, fumes and gases, and such lavatory shall be kept and maintained in a hygienic and sanitary manner and provided with a sufficient number of basins or spigots with adequate washing facilities, including hot and cold water, clean individual towels and soap, and sufficient shower baths, and the dressing room shall be furnished with compartment lockers, so that the ordinary street clothes of such employees shall be kept separate and apart from their working clothes. Male and female employees shall be provided for separately.