9 the tailings are permanently stored at uranium mill sites. Air sampling has demonstrated that there is no health hazard to the population surrounding ’ the mill sites. Stabilization of the tailings is required in Colorado, and other uranium milling states are considering such control. | If this refers to the natural radionuclides liberated in burning fossil fuels the AEC does not have responsibility for measuring natural radionuclides released in this process. | Inventories of radionuclides by source do not bear a direct relationship to risk-vs-benefit balances. The inventory of radionuclides deeply buried - underground following nuclear weapons test events must be considered as unavoidably associated with these events which are conducted as part of the U. S. national security program as were former weapons tests in the atmosphere. The risk of contamination of ground water is minimal since it is known that movement of ground water on the Nevada Test Site is very slow, i. e., it is believed to be significantly less than 100 feet per year. At this slow rate of movement , it would require several hundred yeers for the water to move to a point of known use as a public water supply. this time radioactive decay continues. During The potential dose commi tment to ' the user would then be considerably lower than the guidance for radlation protection provided by the Federal Radiation Council. No Plowshare feasi- bility experiment is conducted until the AEC, through a series of safety studies in all known areas of the environment in which there could be problems of health and safety to the population, has assured itself that .