we Gnas, evaluating possible genetic effects. The average whole body exposure to persons in the United States (to be accumulated over 30 years) from all past nuclear detonation tests (United States, United Kingdom and USSR - the Franch tests contributed very little) has been estimated to be 110 milliroentgens” (0.11 roentgens)!-. Somewhat over one-half of this exposure will result from radioactive fallout materials outside the body with the remaining percentage due to cesium-137 and carbon-14 internally deposited through ingestion (inhalation contributes negligible amounts). Evaluation A whole body exposure of 175 roentgens (Marshallese experience in 1954) is far in excess of an acceptable exposure. As contrasted with the surface bursts in 1954, the 1962 U. S. tests in the Pacific were t bursts in the air high enough above the surface to eliminate measurable local fallout. t 4 « Only a few individuals exceeded by small amounts the criterion of 10 roentgens in 10 years established for the Nevada Test Site. The whole body average population 30 year exposure of 110 milliroentgens (0.11 roentgens) is about three percent of that from natural sources. The difference in natural background radiation levels at * A milliroentgen is 1/1000 of a roentgen. tee 2 (ee, on hie