Cohn, Robertson, Conard (figure 1). Gejen, an uninhabited northern island. received the highest dose. 2.000 1; Rongclap (from which it was necessary to evacuate the mbhabitants) received an intermediate dose of 175 rand Utirik Island to the east received 14 r in the first 2 davs. The dose rate on the Rongclap Atoll, as measured a9 €09 2° TTS ATOLL o at INGIN ATOLL 50 STATUTE MILES 0° — ee RONGERIK RONGELAP ATOLL ATOLL 100 50 | ©ar BIKAR ATOLL O16;aN 12° ° UTIRIK ATOLL & TAKA ATOLLU UTIRIK ISLAND 200 _ 166° 168° ! 170° 4 10° Ficure 1}, Isodose lines of estimated pattern of radioactive fallout. Pacific Proving Grounds. March 1. 1954 The numbers on the map represent the doses that would nave neem Tecencd over approuumatelh 48 hour without shielding The dose. above wiuch sumnval is unkkely ws $00 1. and below winch survival is probable is 200 1 ifrom Cronkite et af, 1956. initially and over a 5-vear period. is presented in table 1. The values of dose rate at }] vear varicc from 0.5 mr/hr on Rongelap Island to 3.0 mr/hr on Kabclle Island. These values represent averages, as the levels of activity were not uniform on each island. The rapid fal] in gammaactivity over the first 2-vear period reflects the high percentageof short-lived radioisotopes which contnbute Tape 1. Average gamma dose rates on Marshall Islands following nuclear detonation of March 1, 1954 {from Held, 1958) Gammaexposurelevels Rongcla Atoll imr/her at 3 ft above ground) Rongelap Island Jan. V5 5eee Oct. 1955 JOH 1956eee 0.5 2.0 0.2 0.4 Pade W957 neeeeecceeernee 0.07 March 1939 ow veces teen 0.035 March 1958 oe Aug. 1958 nee Eniaetok Iskand Kabelle Island 3.0 12 0.029 0.058 0.067 0.076 0.048 308 6.20 0.14 0.16 0.10