The main statute protecting the health and safety of workers in the workplace is the Occupational and Safety Health Act (OSHA). Congress enacted this legislation under its Constitutional grant of authority to regulate interstate commerce. OSHA requires the Secretary of Labor to promulgate regulations and safety and health standards to protect employees and their families. Every private employer who engages in interstate commerce is subject to the regulations promulgated under OSHA.
Under OSHA states are not allowed, without permission of the Secretary of Labor, to promulgate any laws that regulate an area directly covered by OSHA regulations. They may, however, regulate in areas not governed by federal OSHA regulations. If they wish to regulate areas covered by OSHA regulations they must submit a plan for federal approval. The amount of state regulation varies greatly. California is an example of a state that has chosen to adopt many of its own regulations in place of those promulgated under OSHA.