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SummerHill Apartment Communities 10391.000.000 Rollins Road-Carolan Avenue, Burlingame November 19, 2014, Revised January 14, 2015 laterally, with subsequent confirmation sampling. This process will continue until all concentrations are below the applicable screening levels. Excavation base discrete soil samples will be recovered from the center of 20 by 20 foot grids identified with soil impact for laboratory testing (minimum one base sample per excavation). Sample grids exhibiting COPCs in excess of the corresponding residential ESLs will be excavated an additional twelve inches vertically with subsequent confirmation sampling. A minimum of one sample will be recovered for each sidewall on a 20 lineal foot basis. Sidewall samples will be recovered from the mid point of the sidewall on a 3 vertical foot interval. This process will continue until the laboratory testing shows that the soil left in place is below the corresponding ESLs. If groundwater is encountered within any remedial excavation, a grab water sample will be recovered in addition to the base sample(s). Soil samples will be recovered using a hand slide hammer and 2 by 6 inch stainless steel liners. The sample liners will be sealed using Teflon® sheets secured by tight-fitting plastic end caps. Upon collection of samples, a sample label will be placed on the sample and will include a unique sample number, sample location, time/date collected, laboratory analysis, and the sampler's identification. For volatile organic analyses (TPH-gasoline, 8260) samples will be recovered using 25-gram Encore samplers (EPA 5035). The soil samples will be placed in an ice- cooled chest and will be submitted under documented chain-of-custody to a State-accredited fixed-base analytical laboratory. The samples will be analyzed for the following target analytes: • Total petroleum hydrocarbons (TPH) as gasoline (EPA Method 8260) • Volatile organic compounds (VOCs) (EPA Method 8260) • TPH as diesel and motor oil(EPA Method 8015M) • CAM 17 Metals (if required based on initial screening) • SVOCs (SIM) (if required based on initial screening) This required additional soil sampling and laboratory testing protocol will be particularly important at the 1019 Rollins Road parcel where recent laboratory testing found that the backfill soil within a former UST and sump excavation is impacted by total petroleum hydrocarbons as gasoline. Soil samples collected at a depth of 8 to 8.5 feet below the ground surface were found to contain mineral spirits ranging from 1,100 to 11,000 mg/kg. Soil samples collected from a depth of 12 feet below the ground surface were non-detect for gasoline. It appears that the petroleum hydrocarbon contamination within the former tank excavation is limited to the excavation backfill soils and does not extend below the bottom of the former excavation. The proposed Site grading plan and cut/fill plan shows that this portion of the Property will be excavated as part of the underground parking structure (Figure 5). The planned depth of cut of about 6 to 8 feet will remove the area of gasoline-impacted soil. The former tank areas can be geo-located prior to Site demolition and the beginning of grading. -9- E&GEO Expect Excellence—