©) f) D anei nenrinted bees : acrl ao : . from: Radist’an-Associated Thyroid Carcinoma . . . : ele 2s Corot, TOL, et al Cy Ceune & Staton, Ine. SUMMARY OF THYROID FINDINGS IN MARSHALLESE 22 YEARS AFTER EXPOSURE TO RADIOACTIVE FALLOUT Robert A. Conard, MD Medical Department, Brookhaven National Laboratory Upton, New York 11973 BACKGROUND Inhabitants of several atolls in the Marshall Islands were accidently exposed to fallout radiation following a detonation of a high yield thermo-nuclear device during experiments at Bikini in the Pacific Proving Grounds in March 1954. An unpredicted shift in winds caused deposition of significant amounts of falleut on four inhabited atolls to the east of Bikini (see Fig. 1) and also on 23 Japanese fishermen aboard their fishing vessel, the Lucky Dragon. Sixty-four inhabitants of the island of Rongelap, 105 nautical miles away from the detonation, received the largest fallout exposure (an estimated dose of 175 rads of whole-body gamma radiation, contamination of the skin sufficient to result in beta burns, and internal absorption of radioactive materials through inhalation and ingestion). Another 18 Rongelap people, fishing on a nearby atoll (Ailingnae), where less fallout occurred, suffered lesser effects (receiving an external gamma dose of about 69 rads). There were 28 American servicemen on the island of Rongerik further to the east who received about the same exposure as did the Rongelap people on Ailingnae. Lastly, 157 Marshallese on Utirik Island, about 200 miles further east, received an estimated 14 rads of whole-body radiation. These islanders were all evacuated to the Naval Base at Kwajalein,to the south, by two days after the accident, where they received medical examinations for the following two months. The Utirik people showed few if any effects and were returned to their home island. The American servicemen, who showed only slight effects, were later returned to duty. The Rongelap people showed the greatest effects and lived temporarily on an island to 241