SITE INFORMATION AND CORRESPONDENCE

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Mr. Robert Chambers Page 2 DecpmbPr 6. 1990 Based on data presented in the HRA, Department staff have estimated the lifetime cancer risks associated with residential exposures to the carcinogenic PAH' s in the deeper soils. These risks are an order of magnitude higher than those presented in the HRA for a Maximum Exposed Individual (MEI) . Whereas the lifetime ciancer risk for the MEI in the HRA was calculated as 1. 1 x 10 , that risk wgs calculated_5by Department staff to be on the order of 1 x 10 to 3 x 10 if long-term exposure to the deeper soils in the area of the former storage facility occurs. The Department finds that the health risks associated with long-term residence in the area of the former storage facility may be significant unless proper mitigation and/or control measures are taken. This finding is based on the carcinogenic PAH concentrations as stated in the HRA. Obviously, the availability of actual carcinogenic PAH data, resulting from analyses performed by more sensitive methods than previously used, may change the basis of this finding. The Department also cautions that additional contamination may be present at this site in areas which have not been thoroughly sampled. Sampling to date has been directed toward characterization of the contamination resulting from the oil storage facility. Because of the historical uses at this site and other nearby sites, it is possible that pipelines, pumping and heating structures, sumps, discarded containers, or other possible sources of contamination are buried at the site. This is illustrated by the uncovering of a concrete structure and drums containing oily wastes during excavation of a drainage channel at the site in December 1989 . A review of our files indicates that there has been no adequate response to our request of September 21, 1989, that another sampling round of the deep monitoring well installed in 1989 be conducted, and that the sample be analyzed for PAH' s (EPA Method 8310) and Aromatic Volatile Organics, (EPA Method 602) . In summary, the Department finds that there is not a significant risk to public health from heavy metals and pesticides in those areas of the site which lie outside of the former oil storage facility. Because there may be a significant health risk to future residents living in the area occupied by the former oil storage facility, institutional controls and/or mitigation measures are warranted in order to eliminate or reduce exposures. Additional characterization of the site, to determine if additional buried contaminant sources exist, should be considered. Also, additional groundwater sampling is needed to confirm that there is no impact to groundwater.