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Between 2019 and 2023, Haley&Aldrich, Inc. installed and sampled a total of 79 off-Site, depth-discrete <br /> soil vapor probes at 2S locations to evaluate the potential for vapor intrusion (VI).The results of the soil <br /> vapor sampling and the building specific evaluations support the conclusion that the VI pathway is not <br /> complete in the investigation area. Soil vapor trichloroethene (TCE) and cis-1,2-dichloroethene (cis-1,2- <br /> DCE) concentrations did not exceed the applicable environmental screening levels (ESLs) in the shallow <br /> soil vapor samples collected in these investigations (from a depth of S feet bgs),which is a direct <br /> indication that the probes are not within an existing plume or contaminant source area. Additional <br /> supporting background information is provided below: <br /> 1. Historical release areas where soil may have been affected by volatile organic compounds <br /> (VOCs) are shown on the attached map and these areas have been remediated by soil vapor <br /> extraction. Concentrations of Site chemicals of concern in soil were limited to these historical <br /> release areas associated with former Site operations (on-Site at the decaffeination building and <br /> industrial sewer leaks west and southwest of the Site). Regardless, none of the soil vapor probes <br /> proposed for decommissioning are located within the suspected release areas.This is confirmed <br /> by Water Board findings that there are no vapor concerns in the areas where the soil vapor <br /> probes are located (see attached letter). <br /> 2. During soil vapor probe construction, soil cuttings were screened for VOCs using a <br /> photoionization detector. Soil headspace concentrations were less than 1 part per million (ppm) <br /> and no odor was noted in construction logs. Additionally, the soil waste generated during soil <br /> vapor probe construction was analyzed by a laboratory for disposal, and Site chemicals of <br /> concern were not detected in the soil samples. <br /> 3. The soil vapor probes were constructed entirely in unsaturated soil and therefore do not <br /> encounter groundwater. <br />