The data from the Balloon facility of Area 5 and the T-1 site of Area 1 contain However, these represent such a small many plutonium concentration numbers. fraction of the total area of these sites that again, no plutonium distribution can possibly be estimated. However, an upper limit to the plutonium inventory can be estimated. The data from the Small Boy site of Area 5 include a good fraction with plutonium concentrations. However, these concentrations vary considerably between adjacent sample locations, and it is not clear if these data can be used for more than determining an upper limit of the inventory for this site. Sampling in Area 4 had been terminated until evaluations of the usefulness of this sampling approach can be made. Area 4 data have not as yet been examined to determine usefulness. Current efforts of the PIDP studies are being directed at the evaluation of the program's sampling and analysis procedures, as well as quantification of the plutonium in the sites sampled to date. CONCLUSIONS Although thousands of soil samples have been taken, and sampling has proceeded from site to site and area to area, the current data are not sufficient to estimate distribution of plutonium for more than one or two of these sites. A limit for maximum plutonium inventory for each site can be made, but this would probably not be much more accurate than a mass balance on the original device. In order to estimate both plutonium distribution and inventory for all sites sampled to date, most of the soil samples will need to be analyzed for plutonium by wet chemistry, or by Ge(Li) scanning with more sensitive instruments (Pu inferred from Am-241). The only other alternatives are to resample by some more sensitive procedure, or to infer plutonium concentration from the fission product data. In the latter case, plutonium inferrence from Cs-137 does show promise. 236