Hematogical Effeet: STATE OF I HEMATOLOGICAL EFFECTS ON HEAVILY IRRADIATED JAPANESE FISHERMEN TosHIyvuk! KuMaToal The fishermen were im (i) From the radioacti (2) Externally from th (3) the deck etc. Internally from th The diameters of the f Division of Radiation Health, National Institute of Radiological Sciences reef fragments, ranged fron + 1934). According to the March, rare-earth elements Chiba, Japan activity and uranium contril INTRODUCTION On | March in 1954, a thermonuclear test explosion was performed by the United States Authorities at Bikini Lagoon in the Pacific Ocean. At that time one Japanese fishing boat “the 5th Fukuryu-maru” was located at about 90 miles east from explosion center. The boat was nearly 100 tons and 23 fishermen aged from 18 to 39 were on board. At about 3:40a.m., while they were occupied in fishing tuna they saw a huge red light in the west and heard a detonation several minutes later. specific activity of the mate of these data, a value of 1. a.m. on 1 March. The € internally deposited racioa However, radiation fr lesions. External radiatior exposure dose for 14 days cent of these doses was re on the results of the exp decay curves of many pl At about 7:00 a.m. white material began to fall, which continued for ap- Table 1 proximately 5 hours. They gave up fishing and returned to their mother port on 14 March 1954. Esti Subject No. T-1 red bo After landing, all the fishermen were found to have been injured by the radioactive materials. Seven of them were hospitalized to the Tokyo University Hospital and the other 16 were received by the First National Hospital of Tokyo by 28 March. They were discharged from both hospitals in May 1955, except for one fatal case who died on 23 September 1954. After being discharged we continued the follow-up studies so far as possible on annual basis. However, mainly because of the varied status of their occupations and widely distributed addresses, it was not always possible to get them all to- gether fur medical examination. Medical data of the fishermen have been reported several times (Mryvosut and Kustatorr, 1955; Koyama et al., 1955; Mrxamo et al., 1956; Mrrosut and Kumatort, 1962; Kesatorr and Mryvosu1, 1963; Mryosnr and Kumatoat, 1964; Kumatorr et al., 1963). FALLING OF RADIOACTIVE MATERIALS Nuring the falling of the white materials, when its intensity was greatest, these persons were unable to keep their mouths and eyes open. prints were clearly marked on the deck covered by fallout. Their foot- * T-3 put the fall-out m added in total.