iod of build-up was in its initial phase and the operational T/D's were placed into effect. The J-1 Division continued to fillremaining vacancies and it appeared that the orerational T/D's were adequate except for military police, radiological safety person- nel, and signal personnel. Arrangements were made to have assign- ed twenty~five additional MP's, fifty Army and Navy radsafe-trained personnel, and several Signal Corps specialists to serve ona temporary duty (TDY) basis in the forward area during the operational phase. This illustrates a peculiar personnel problem which regularly confronts the Task Force—that is, the recurring requirements for relatively short periods of time of highly qualified and security cleared personnel. Planning in the J-2 Division occurred alongside the very large effort required for the paper work connected with personnel clearances, Though this work continues throughout an entire operation, the heaviest period for CASTLE occurred during the latter half of 1953 and then progressively fell off as the operational period approached. The mass of detail and the actual working hours consumed in the personnel security program must not be underestimated as it constitutes a very significant aspect of J-2 Division activity. The J-2 planning for CASTLE~~as for previous operations—~had to be extensive and detailed, attempting to foresee every possibil~ ity for a compromise of the overall mission. The prevention of such compromise is a major problem for the Task Force. Existing regulations establish a security standard which is virtually 43