The broad title of occupational health and safety specialist includes all occupational health and safety professionals who work to eliminate illnesses and injuries in the workplace. These professionals evaluate and communicate the risks associated with hazards and develop methods to control or eliminate them. Occupational health specialists may measure, evaluate, and control chemical or radiological exposures, redesign machinery to reduce the risk of injuries, or perform job safety analyses to identify risks associated with particular work tasks. These professionals develop and update global as well as site-specific hazard control programs, which they later evaluate for effectiveness. Occupational health and safety specialists comprise professionals from many disciplines, including industrial hygienists, safety engineers, occupational and health technologists, ergonomists, risk managers, toxicologists, and occupational nurses.