SOURCES OF RADIATION

a. General. There are two sources of radiation (natural background radiation and man- made) both of which are harmful to man.

b. Natural Background Radiation. There are three sources of natural background radiation: cosmic, earth, and internal. Although natural background radiation may be harmful, man has lived in this environment without significant injurious effects since his appearance on earth.

c. Man-Made Radiation. Man-made radiation has many sources. Some of them are from medical and dental radiographs, occupational exposure, fallout from weapons testing, television sets, and certain radioactive watch dials, clocks, and meters. Man-made radiation, used improperly, can be significantly more harmful to man than natural background.