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Waste Management Unit Report -4- 10 September 1991 DDRW, Tracy Page 2-9. The WMUs were classified into three groups for the soils gas investigation. WMUs in Groups I and II were investigated using soils gas, however WMUs in Group III were not investigated using soils gas. Soils gas investigations were not conducted at WMUs 3, 6, 12, 21, 24 and 27. The Report did not indicate why these particular WMUs were not included. It appears that the criteria for selecting a WMU for a soils gas investigation may have been inconsistent. In particular, WMUs 14 (Lube Oil Dump) and 23 (Building 26 Recoup Operation) were investigated using soils gas, but WMUs 6 (Building 28 Sump) , 24 (Building 247 UGT) and 27 (Building 206 Roundhouse Sump) were not investigated using soils gas. The soils gas investigation included analyses using the EPA Method 602 which detects the presence of BTXs. Therefore, because BTXs may have been constituents in the fuels and/or waste oils and because fuels and/or waste oils were disposed of at all of these WMUs, the soils gas investigations should have included all WMUs at which fuels and/or waste oils were disposed. A soils gas investigation was not conducted at WMU 12 (Embalming Fluid Dump) . The primary constituents in embalming fluid are formaldehyde and methanol . Because these constituents are volatile, a soils gas investigation of the Embalming Fluid Dump should have been conducted to determine if the vapor phase of these constituents is present in the area of WMU 12. Page 2-9. The Report states that nine contingency samples were collected for additional coverage of a WMU. All of the contingency samples were collected at WMUs classified as Group I or II . It would have been more appropriate if the contingency samples could have been collected at some of the WMUs listed in Group III. Page 2-12. The Report states that EPA Methods 601 and 602 were used for analysis of the soils gas samples. It would have been more appropriate to have used EPA Method Modified 8015-5030 (Purge and Trap with Flame Ionization Detector) in some of the WMUs as this method is used to screen for any volatile organic solvent. Table 2-1 . Table 2-1 is a summary of previous investigations of the WMUs. This table is extremely useful and we commend WWC for the preparation of this table. Page 3-8. The Report states that rinse waters from the paint spraying and stripping operations at Building 255 were sent to DDRW, Sharpe for disposal . Because both DDRW, Tracy and DDRW, Sharpe are Defense Logistics Agency sites and because DDRW, Sharpe will be conducting the Feasibility Study for soils in the near future, more information is needed on the ultimate disposal site of these wastes at DDRW, Sharpe. In addition, the Report states that soils from the bottom of the old unlined industrial lagoon were disposed of off-site in 1972-1973. Commonly, sludges from industrial waste ponds may contain hazardous concentrations of waste constituents. The Report does not state whether or not it is known if the wastes were hazardous or where the wastes were disposed.