Every factory or workshop in which one or more persons are employed shall be so ventilated while work is carried on that the air will not become injurious to the health of the employees, and shall also be so ventilated as to render harmless, as far as practicable, all injurious gases, vapors, dust, or other impurities generated in the course of the manufacturing process or handicraft carried on therein.
Ca. Lab. Code § 2351