This chapter illustrates the role of scientists in occupational health policy by examining three areas. They are the work of the International Commission on Radiological Protection (ICRP), the work in the area of chemical hazards of the American Conference of Governmental Industrial Hygienists Inc. (ACGIH), and the provisions of the International Labour Organization (ILO) Occupational Health Services Convention. All three cover a large area of occupational health (rather than safety) issues. Other health hazards would include non-ionizing radiations, noise, vibration, stress, poor work design, and non-traumatic back injury. With radiation protection, there are some possible criticisms of the science which is practiced but, moreover, there are deep faults in the scientific strategy for protecting workers' health. Though physicians are concerned primarily with treatment, there is an ideology of occupational disease prevention which is sometimes used to legitimize the role of physicians in the occupational health disciplines.