Once the full scope of the cleanup problem was known, there was no change to the inclusion of all transuranic isotopes. Other developments, reported in the next section, overshadowed any questions that remained concerning the "change" from plutonium to transuranics. 2.2.4 Cleanup Criteria In the interagency meeting of August 1972 (discussed in Sec, 2.1.1), the suggestion was made that it probably would not be difficult to establish criteria for the cleanup of the so-called "clean" islands because in large measure cleanup would simply be removal of debris. For the so-called "dirty" islands, the potentially enormous quantity of debris and soil for removal suggested a requirement for policy determination as to the final disposition of contaminated soil The alternatives appeared to be in situ burial, lagoon or crater disposal or engineered storage in the continental U.S. The only alternatives to cleanup appeared to be fixation of the contaminants, a permanent quarantine or denial of access to areas of concern. As part of the 1972-73 engineering survey, it was necessary to make certain assumptions regarding the maximum level of contamination below which no cleanup would be required and to propose disposal methods for soil failing the criteria. The engineering criteria for estimating the magnitude of cleanup, with respect to residual plutonium, were stated as follows: "], Residual plutonium will be limited to 500 pCi/g (500 pico Curies of plutonium radioactivity per gram of soil) which is equivalent to 500 micrograms of plutonium - 239 per square meter of soil through the top 5 cm (2 inches) of soil "2, "3. For site Yvonne (Runit Island) regions exceeding 500 pCi/g of soil will be removed to a depth of 24 inches. Any soils with surface contamination exceeding 50 pCi/g not already diffused to a depth of 10 inches or more will be plowed to this depth." Areas with soil above the residual level limitations were to be reduced to the limits by either removal of soil or covering with soil having negligible radioactivity. transported to only one of three alternate areas: Removed soil was to be "], Soil shall be removed to an island with minimal uses for other purposes, such as Runit Island, and used as intermediate "land fill" over contaminated metal and debris. "2. Soil shall be removed to an underwater disposal area (either at sea or in the lagoon) and dumped. "3. Soil shall be encased in containers and returned to Conus (continental United States) for burial at a designated location to be determined.” The above criteria were used solely as the basis for constructing scope-of-effort estimates of the cleanup project and had little bearing on final cleanup criteria, although the alternatives mentioned were each evaluated extensively in later deliberations. The AEC Task Group was assembled in 1973 to develop judgements and recommendations on cleanup and rehabilitation of Enewetak Atoll. The Task Group effort was to arrive at a thorough understanding of the extent and character of the radioactive contamination in the atoll and, more importantly, to examine the implication of this contamination for continuous and long term human habitation. The Task Group based its recommendations on an extensive review of federal and international radiation exposure guidelines and the results of the 1972-73 radiological survey of the atoll. The first draft of Task Group recommendations was distributed to selected agencies for review and comment on 1] February 1974. On 6 March, an interagency meeting was held to discuss the draft report. Summary notes of this meeting by an AEC representative enumerate the different agency views and differences of opinion and are quoted at length below: 58