shielding from the crater's nuclear radiation to the surface op@rations. Scientific stations were built on Dridrilbwij for CASTLE, the ifBland next to the Eluklab crater, and no mention of special difficulties dfhe to radiation is made in the construction report, although personnel fillm badges were still required. Bikini was the location of the first postwar nuclear detonakion. In July 1946, the CROSSROADS tests were conducted in the lagoon. wo 23-KT devices were detonated: Ehe second one airburst over a target fleet, and burst underwater in the lagoon about 2 nmi (3.7 km) west of Bikini Island. There was no continuing radiological exposure of personnel on the surface at Bikini from these tests, although there was very-low-level qbntamination in the lagoon bottom. Special Problems in Oceanic Testing Testing in the Marshalls offered a large uninhabited area r test ac- tivities and for the favorable disposition of the test debris §f the winds were in the right direction. However, the area was almost all Jwater, of- fering little dry space to place shot towers, instrumentation test structures, or places to live. is only about 1,800 acres At Enewetak Atoll the totdl land area (730 hectares), and the prime acreag¢ southeastern quadrant (about one-third of the total) the task force not based on ships. housed that part of The land area of Enewetak largest of the atoll, is only about 320 acres in the (130 hectares), [sland, the gnd about half of this was occupied by an airstrip and associated activifies. Fur- thermore, the land suitable for testing was not necessarily diBtributed in the appropriate directions and sizes for instrument placement. Lack of land area was one of the factors necessitating use of both Bikini and Ene- wetak atolls, starting in 1954 with CASTLE. The addition of precluded damage to the Enewetak facilities by very-large-yielfi kini also devices. The lack of land was compensated for in part by civil engifheering projects. Causeways were constructed that linked strings of islanfs to support the long pipe runs of some experiments over thousands of feet} 51 These also