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Geocon Project No. S2170-07-12 - 2 - June 6, 2022 The Phase II ESA included a soil vapor survey to assess the potential presence of VOCs in soil vapor across the Site. Petroleum-related VOCs were detected in soil vapor at the Site, but at concentrations less than the LTCP criteria for residential use both with and without a bioattenuation zone, though oxygen concentrations ranged from 12 to 19% suggesting a bioattenuation zone is present. PCE was detected in soil vapor samples SV4 and SV5, both located in the southwestern portion of the Site (Figure 2), at concentrations of 21 and 22 micrograms per cubic meter (µg/m3) respectively, which exceed the ESL for PCE in soil vapor in a residential setting of 15 µg/m3 but is less than the ESL for commercial setting of 67 µg/m3. The PCE concentrations only slightly exceeded the ESL for residential use, but additional assessment is required to determine the extent and potential source of PCE on the Site. The proposed project consists of redeveloping the Site and constructing two multi-story, apartment buildings (Buildings 1 and 2) and associated improvements (Figure 2). Buildings 1 and 2 will be five- and six-stories, respectively. Residential units are not planned for the ground floor of either building. The ground level of Building 1 will have a community center and leasing office and Building 2 will include ground level parking. PURPOSE AND OBJECTIVE The purpose of the soil vapor assessment is to further assess the lateral and vertical extent of PCE in soil vapor on the southwestern portion of the Site and determine if it presents a potential human health risk for future users of the Site. The objective of the soil vapor assessment is to collect representative soil vapor samples for VOC analysis. SCOPE OF SERVICES The planned scope of services includes the following tasks: • Task 1 – Pre-field activities: health and safety planning, soil vapor well boring permitting, subcontractor and equipment procurement, and utility clearance; • Task 2 – Field activities: advance borings, install temporary soil vapor wells, collect soil vapor samples, and remove the temporary wells; • Task 3 – Laboratory analysis of soil vapor samples; and • Task 4 – Reporting. Task 1 – Pre-field Activities We will perform the following pre-field activities: • Update the existing site-specific Health and Safety Plan (HSP) describing the physical and chemical hazards of the work to be performed, provide health and safety guidelines protective of Geocon field personnel, and identify emergency contact personnel and the nearest emergency room (a copy of the HSP is attached); • Obtain a boring permit from the SJCEHD and coordinate with them so that a SJCEHD inspector is onsite for boring abandonment; • Retain the services of Eurofins Air Toxics (Air Toxics), a National Environmental Laboratory Accreditation Program-certified laboratory in Folsom, California, to provide equipment for and perform chemical analysis of soil vapor samples, and