ved SECTION I. - RADIATIONS A. 1. General Background Information Natural background and Medical Exposures. As far as is known, man always has and always will live in an environment filled with radiation. There are radioactive materials present naturally in the ground, the sea, and in the air. esi sree bombard us from outer space. Cosmic rays Naturally occurring radioactive materials in our food supply irradiate us from within. “To these levels of radiation exposures are now added those from fallout - but these radiations (gamma rays and beta particles) are no wth different in kind from those emanating from natural sources. Nor is there any evidence that they produce any fundamentally different biological effects than those from natural background radiations. The radiation from natural sources and those from medical, industrial, and scientific uses of radioisotopes and X-ray machines, and their biological effects, have been studied intensively for many years. - To repeat, radiation exposures from fallout are in addition to those from natural sources but they are just that - additions of more of the same type of radiation. Fallout has not introduced a new and strange agent into our environment with completely unpredictable results. Indeed, a Committee of the National Academy of Sciences-National Research Council has stated: " . . . Despite the existing gamps in our knowledge, it is abundantly clear that radiation is by far the best understood environmental hazard . 7) 2.