fallout from a nuclear device detonated at the Pacific Proving Ground in the spring of 1954. Fallout began to arrive 4 to 6 hours after burst, anu at about 50 hours after burst, the natives were evacuated. These people were not aware they were being exposed to fallout, and were not aware of its significance. sgecial precautions. They remained out of doors and took no For example, they continued to drink wate» cul- lected in open cisterns. Early estimates of the maximum external doses were about 175 roentgens and the maximum internal doses were estimated to be between 100 and 150 Rads to the thyroids. 6 Later recalcu- lations of the thyroid doses in the smaller children due to radioiodine indicated they may have been in the range of 700 to 1400 Rads. ; During the past few years, abnormalities have been detected in thyroid glands of some of the people exposed. The following is quoted from a report of the medical survey conducted in March 1966 of the people of Rongelap and Utirik Atolls. "Among the Rongelap people, in whom nodules of the thyroid gland had first been detected three years ago, a further increase in cases with nodules was noted. There has been a total of 16 cases in the 69 people now living (of the original 82 people exposed), 15 in the more- heavily-exposed group, and 1 in the less-exposed group. Thirteen of Rt 19 children in the more-heavily-exposed group, all of whom had been