The federal Occupational Safety and Health Act (OSH Act) is “preemptive” that is, it overrides state work safety and health laws and regulations in the areas that it covers. Since it covers virtually all areas of workplace health and safety in the private sector, it supplants most state work safety requirements. Under the OSH Act, individual states may devise and administer their own standards, but only with federal approval and only if the applicable state requirements are as stringent as the corresponding federal standards.
Because New Hampshire has not adopted such a plan, federal standards prevail and govern health and safety in the private sector (businesses and nonprofit organizations). There are comprehensive discussions of the federal standards.