5 being returnedto these islands. It became appar- ent that a special vessel was needed, and in 1973 the AEC arranged for the Army to provide an LCU(landingcraft utility) based and maintained at Kwajalein (with AEC funding). This vessel, though small andslow,has the distinct advantage that it can be beached, so that ship-to-shore trans- fer of equipment and personnel by small boatis unnecessary. Three 30-ft air-conditioned trailers have been placed on the tank deck, one equipped as a “sleeper,” one containing a whole-body counter (shadow-shield lead assembly and elec- tronic equipment), and oneset upforclinical ex- aminations with a doctor’s office, a small labora- tory, and an x-rayfacility. The LCU with these trailers is now in full use and affords tremendous improvements in the operations. Examinationfacilities at Utirik consist of several Butler-type buildings left by a weather station group. On Rongelapseveral examinationtrailers have beeninstalled so that the schoolhouse need no longer be used. Examinations trailers have also been installed on Ebeye and Majuro. Major events in the Marshal! Islands related to the surveys, includingthe political problems of the past few years, are summarized in Appendix 1. Before and after each survey, village meetings have always been held on Rongelap and Utirik to inform the people of the objectives of the examinations, the findings, and recommendedtreatments. Because of the language barrier, the people did not always understand the need for the examina- tions, or their results. Every effort is now being madeto correct this. Preparation of a questionand-answer booklet on theeffects of the fallout and treatmenton the Rongelap and Utirik people was recommended by the Congress of Micronesia; such a booklet has been printed at BNL for the Trust Territory Health Services and is being distributed; it should do muchto correct manyof the former misconceptions (see Appendix 4). During the 20 years covered by these reports drastic changes have occurred in the Marshall Islands District. The population more than doubled from 1948 to 1973, the total going from ~ 10,000 to ~ 25,000. The increases were most dramatic on Majuro (going from 1,200 to 10,300) and on Ebeye (going from 750 to 5,000). On the outer islands thetotal population changed less (Rongelap, 100 to 167; Utirik, 126 to 217), but the age distribution be- came abnormal. Youngadults have gravitated to- wardthe district centers, and the “homeislands” are left with children and old people. A recent survey on Rongelap showedthatofits 167 people, 115 were <15 years old and 30 were >50. The flux is great: during any givenfield trip up to 30 people maybearrivingorleaving. The district has opened up to foreign travel. Majurohasa jet airport, paved roads, electricity, and telephones. Expectations are rising, and when public services fail to keep pace with increasing demand,dissatisfaction is more vocal. T'xe atmospheric bomb tests ended in 1958. Kwajalein was abandoned as a Navy Base in 1960 and was made part of the Army’s missile test range. For the visiting medical teams, loss of Navy assistance in transportation has increased the logistic problems, but the continuing support of the ArmyBase has been invaluable. The people of Rongelap and Utirik have always been most friendly and cordial to the medical team. Except for political interference with the 1972 examinations, the people have always been cooperative. Hl. Initial Findings A. DOSE ASSESSMENT 1. Source The radiation exposure of the Marshallese was due entirely to fallout, since the detonationsite was too far away for thermal, blast, or direct irra- diation effects. (In constrast, direct effects were responsible for all the injuries from the atomic bombs in Hiroshima and Nagasaki, withlittle or nofallout.) The fireball from the 1954 Bravo device, detonated from a tower, touched the surfaceof the earth at Bikini, and large amounts of material were drawnup and mixed with fission products in the bombcloud. Because of an unpredicted shift in the winds in the upper atmosphere,fallout was deposited in a cigar-shaped area 20 to 40 miles wide extending ~ 200 miles to the east of Bikini (see Figure 1). The radioactivity was duetofission products and some neutron-inducedisotopes; the fallout containedlittle fissile material. The radiation was therefore almost entirely from gamma and beta rays of varying energy from numerous fission radioisotopes. The time after detonation whenfallout began was estimated as 4 to 6 hrat Rongelap, ~7 hr at Rongerik, and 22 hr at Utirik