Every factory, mill, workshop, mercantile or mechanical establishment or other building, where one or more persons are employed, shall be provided within reasonable access, with a sufficient number of water closets, earth closets or privies for the reasonable use of the persons employed therein, and wherever male and female persons are employed as aforesaid together, water closets, earth closets or privies separate and apart, shall be provided for the use of each sex, and plainly so designated, and no person shall be allowed to use such closet or privy assigned to the other sex. Such closet shall be properly enclosed and ventilated and at all times kept in a clean and sanitary condition. When the number employed is more than twenty of either sex, there shall be provided an additional closet for each sex up to the number of forty and above that number in the same ratio. The Department of Labor or any person authorized by the department may require such changes in the placing of such closets as the department may deem necessary and may require other changes which may serve the best interest of morals and sanitation.