OFFICIAL USE ONLY excess of 100 uR/hr were found. (Surface radiation readings were made at 3 feet.) No radiation debris at any levels of activity was buried on the islands of Bikini, Eneu, or Aerokoj. The exterior of several bunkers, located on the northern complex (Iroij, Odrik, Lomilik, and Aomen) and Nam, exhibited contact levels of radiation up to 7,000 uR/hr, combined beta and gamma. The net gamma levels were 200 uR/hr maximum. The levels inside the bunkers were less than 10 uR/hr. Natural background in the U.S. is about 20 uR/hr. Since the potential for personnel exposure was negligible and the bunkers were desired as typhoon shelters and storage buildings by the natives, the larger bunkers were left intact. 2.3 BIKINI ISLAND The island was prepared for agricultural redevelopment by cutting parallel strips through the vegetation along the length of the island. The vegetative cover was knocked down and left in place to provide additional organic matter for the soil. The strips were surveyed and gamma radiation levels recorded at 250-foot intervals along their length. Figure 2 illustrates the variation in these levels by depicting the range and average of gamma radiation measurements taken at three feet above the ground for areas consisting of approximately four strips. Although a large amount of debris was found on Bikini (from the testing program and World War II), the only material found to be radio- active was a pile of roofing paper scraps contaminated primarily with 137Cs located northwest of center on the lagoon side of the island. This material, which showed a contact reading of approximately 200 uR/hr, was loaded into 55-gallon drums and disposed of in one of the disposal sites in the ocean south of Eneu. The measured exposure rates were 10 uR/hr or less along the beaches and ranged from 20-120 uR/hr inland. Soil samples taken at three locations in 1969, having measured backgrounds of 20, 70, and 100 uR/hr, showed 137¢Cs and 60Co to be the major gamma emitting contaminants. These were present in Cs/Co ratios of approximately 25/1, 50/1, and 30/1 respectively for the three samples, and thus the projected exposure rate decay will very closely approximate the decay of 137Cs. In addition, 908r was present in amounts ranging from 10 to 50 percent of the 137¢5 concentrations, 2.4 ENEU ISLAND Eneu, the second largest island in the atoll and the site of the base camp for the clean-up operation, was found to have external radiation levels considerably lower than Bikini (Figure 3). Although an exposure rate of 50 uR/hr was obtained at one depressed location during the early stages of clean-up, filling of this "borrow pit" area reduced the level to approximately 10 uR/hr. than 10 to 20 uR/hr. The exposure rate generally ranged from less 4 OFFICIAL USE ONLY