CHAPTER VI eam oe Return of Rongelapese One of the major consequences of the heavy fallout on some of the Marshall Islands in March 1954 was the evacuation of their inhabitants. The 154 personnel from Utirik were returned to their island in June 1954. However, the contamination of the Rongelap Atoll was appreciably greater than at Utirik, therefore it was not advisable to return the Rongelapese at that time. Since then the contamination has decreased, as shown by the data from the foregoing surveys, to a level where return was permissible. The discussion below summarizes the factors that led to this decision.* A. Medical Status of Rongelapese Relevant to the considerations for the return of the Rongelapese to their homeisland was the body insult they previously suffered from radiation following the fallout of March 1, 1954 and their present body burden of radioactive isotopes. Below are summaries of the findings over a two-year period. Of the Rongelapese exposed, 64 received about 175 roentgens, and 18 people about 69 roentgens whole body external gamma radiation. The clinical findings showed, “. . . The moreseriously irradiated individuals had initial symptoms of anorexia, vomiting and diarrhea The skin damage observed was as follows: 45 individuals—superficial lesions 13 individuals—deep Jesions 6 individuals—nolesions 35 individuals—somedegree of epilation As the Marshallese continued to live on the contaminated islands for the two days before evacuation some radioactive materials were taken internally by inhalation and ingestion. Table 45 shows the results of urinalysis of Group I (the 64 Marshallese exposed to 175 roentgens) and Table 46 the estimated body burden.’ The major findings on internal contamination were as follows: “. . The total amountof radioactive material in the G. I. tract at one day post detonation was estimated to be 3 mcin people from Rongelap. This activity was contributed chiefly by isotopes of short radiological and biological half-life and limited solubility, and thus the levels of activity in the tissues of the body were relatively low. The concentration of radioisotopes at 6 months post detonation was barely detectable in the urine of most of the exposed individuals. “The estimated dose to the thyroid from J#! and other short-lived iodine isotopes was 100-—----—--: which subsided without treatment within 2 to 150 rep for the Rongelapese. Iodine is probably the most hazardous internal radioemitter at early times after exposure. The dose to the granulocytopenia and thrombocytopenia unas- low compared to the partially or totally ablat- days. The same individuals slowly developed sociated with secondary complications. The only other manifestations of radiation exposure observed were skin lesions and epilation, . . The incidence of infectious and noninfectious disease in the more severely exposed groups was no greater than that in the least exposed group... .78 *Tbe Rongelapese were returned to their bome island on June 29, 1957 thyroid, although greater than tolerance, was ing doses of I*! used in the treatment of hyperthyroidism or carcinoma.”* At one day post detonation, the concentration of Sr® was calculated to be near the maximum permissible level for this nuclide. At later times following exposure, this longer-lived fission product presents the greatest potential internal hazard. 45 DOE ARCHIVES