permissible exposure limit An exposure limit that is set for exposure to an hazardous substance or harmful agent and enforced by OSHA (Occupational Safety and Health Act) as a legal standard. It is based on time-weighted average concentrations for a normal 8-hour work day and 40 hour work week
regulation on maximum permissible limitsA body of rules or orders prescribed by a government or an international organization or treaty establishing levels of hazardous materials in the environment or in ingestible substances beyond which human exposure is deemed health-threatening