team monitored the local radiation environment, sampled the air for airborne activity, determined the level of protective equipment needed, and monitored personnel for contamination. The low gamma radiation levels found at Enewetak Atoll would not normally require a full-scale dosimetry program, however such a program was established. All personnel who worked on, or visited, the contaminated northern islands were issued film badges on a monthly basis. Because film badges frequently were adversely affected by climatic conditions, a supplemental dosimetry system making use of thermoluminescent dosimeters (TLDs) was established for personne! working on contaminated islands. TLDs had the additional advantage that they could be read on-atoll. Self-reading ionization chambers (pocket dosimeters) were also issued, as required, to provide backup dosimetry before TLDs were acquired. When earth-moving operations were conducted in contaminated areas, water sprinklers were normally rigged to minimize resuspension of the soil. Personnel were trained (and directed on-site) habitually to remain upwind of any dustproducing operation. Air samplers were set up downwind to monitor for any airborne hazard. These power-operated samplers forced air through filters, which were monitored and changed at two-hour intervals, and subjected to laboratory analysis. During transit, trucks containing soil were wet down and covered with tarpaulins. Personnel involved in earth-moving operations wore appropriate safety gear for the conditions (respirators, protective clothing, etc.). Bioassay procedures (nose swipes, fecal analysis, urine analysis) were established on the atoll and used as required. Urine samples from personnel who worked for extended periods on controlled islands were collected at end of tour and analyzed. The effectiveness of this conservative approach toward sampling the radiological environment, and controlling and measuring exposure to it, is borne out by the very low radiological exposures that were experienced. Exposures to gamma radiation were extremely low level. Of some 12,000 film badge readings, about 83% show zero exposure, and the highest valid reading is about 0.07 rem.* The probability of there having been any internal (inhaled) contamination is similarly very low, as shown by the facts that: (1) More than 5,000 filters from air samplers were collected during the operation, and about one million cubic meters of air were sampled. Over half the filters showed no traces of transuranic element activity, over 95% showed less than one percent of the maximum permissible concentration (MPC), and none showed more than [0% of MPC, ¥The current Federal guideline for allowable exposure for radiation workers is 3 rem per quarter, or [2 rem per year (reduced to 5 rem per year when certain ageexposure limits have been reached).