responses of the two TLD sets gives the beta response. TLDs placed in the field were positioned with the open windows facing the soil. Because shielding part of the dosimeter may bias the data, an attempt was made to predict the resulting error by randomly placing four of the dosimeters (16 TLDs) together, open windows facing the soil, in a series of tests using Ogr-90y as a source, placed 30 cm from the TLDs. The open and closed windows were varied to cover all combinations of field positioning. The error using a point source and a source-to-detector distance of 30 cm was <2.5%. Because the field situation represents a distributed plane source, and the source-todosimeter distance was between 50 and 100 cm, the field situation should have a minimal positioning error associated with the results (Figure 2). RESULTS A total of 203 RSS-111 measurements were made on Bikini Atoll. Each data point is the average of at least 20 individual readings. This assures the precision of the value, and the initial calibration guarantees accuracy. The mean exposure rate is reported with one standard deviation calculated by assuming that the data obtained from a specific site follow a Gaussian distribution. Tables 1 through 5 represent all data taken on Bikini Atoll. lists the data from Nam Island, Table 2 located at the northwest corner of the atoll, closest to ground zero of the BRAVO device. The average external exposure rate over the land areas monitored is 24 uR/hr. This is six times higher than the background levels at Wotje, Ailuk or Utirik Atolls?. This average value should not be interpreted as a true value for the Nam island average, since dense vegetation prevented a representative sample of readings over the whole island. Nam is uninhabited at present and is not used for food production. The exposure rate is non-uniform and varies significantly as a function of location. Table 3 presents the data from Eneu Island, located south and west of Bikini Island. Eneu received the least fallout contamination as evinced from the average external radiation exposure rate of 5.7 uR/hr. This value is 1.5 times the natural background and is the lowest external exposure rate on any of the islands surveyed. Figure 3 shows the sample sites and the exposure rate measured at each site. These data demonstrate the uniformity of exposure rate on this island. The external exposure rate on Bikini Island is a strong function of location (Figure 4A4-E). It is the lowest in the areas closest to the lagoon and current housing*, highest in the center of the island and intermediate in other areas. The average exposure rate for the island, based on an average of all the data is 32.1 uR/hr. Table 4 lists exposure rate measurements made in the living areas of the available housing. Table 5 lists all other exposure rate Measurements made at Bikini Island. *In 1978, the Department of Interior made the decision to relocate the inhabitants of Bikini Atoll to either Ejit Island, Majuro Atoll, or Kili Island. relocation took place in August 1978. The