ABSTRACT
A convenient method of specifying what is meant by low-level electric and magnetic fields is to examine human exposure standards. Safety levels have usually been lowered as knowledge of the effects of electric and magnetic fields has increased. Several different organisations, Underwriter’s Laboratories, the Association for the Advancement of Medical Instrumentation, the National Fire Protection Association, and the US Standards Institute C101 Committee, are all concerned with the hazards of electrical equipment. In standards recommended by British officials, the upper permissible limit of microwave radiation is 10 mW cm-2, with no reference to time of exposure. It should be pointed out that the Soviet studies which led to the 10 µW cm-2 radiation exposure standard dealt with effects on the central nervous system, and included behaviour in humans and pathology in animals. The most hazardous band of frequencies is centred around 50–60 Hz.
