Industry, engineering, telecommunications, medicine, research, education and the home, now use a large number of processes and devices which emit non-ionizing radiation. It is known that the ultraviolet radiation generated from man-made sources can be more intense than that occurring naturally, for example in sunlight. The eye is more sensitive to ultraviolet radiation than is the skin and has a built in safety mechanism by reacting to strong sunlight with contraction of the iris and shutting of the eyelids. This reaction mechanism, however, is not fast enough to protect against very bright flashes, nor will it protect against radiation that is not accompanied by visible light. Thus it is necessary for workers in certain fields (arc welding, for example) to utilize protective devices, such as shields and filters. The resultant possible adverse effects of general population exposure are not yet fully understood, and adequate measures are lacking to inform the public about possible risks.
Non-ionizing radiation includes the high-frequency radiations used in communications and broadcasting; the microwave radiations used in radar, television transmissions, and industrial applications; the infrared radiation used in heat-lamps, and the visible light used in some lasers; ultraviolet lamps, and medical diathermy equipment. Excessive radiation may cause damage to the eyes and skin, and in sufficient dosage, to the internal organs.