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Project No. 014-13157 Page No. 2 soil because it volatilizes upon contact with soil. According to the Formaldehyde Council', Formaldehyde does not accumulate in the environment either, because it is broken down within a few hours by sunlight or by bacteria present in soil or water. Based on the low concentrations detected in soil and the fact that the concentrations do not exceed the established regulatory screening level (USEPA RSL), it does not appear that formaldehyde poses a significant risk to the environment in the areas sampled. Elevated concentrations of TPH-d and TPH-mo appeared to be localized in the soil/debris mounds and former wood and metal debris area along the west central portion of the subject site. The only composite sample (S26, S27, S28, and S29) concentrations that exceeded the ESLs for TPH-d and TPH-mo were located near the western property line (see Figure 2). Although TPH-d and TPH-mo were detected in discrete soil sample S-29A, the concentrations were well below those of the soil sample that composed the composite sample S26, S27, S28. Thus, it appears that the elevated concentrations of TPH-d and TPH-mo were localized in the area of composite sample S26, S27, S28. Krazan recommended that additional soil samples be completed in this area to determine the vertical extent of TPH-d and TPH-mo impacted soil. However, the client stated that they did not want to conduct additional soil sampling, but instead indicated their desire to move forward with a limited excavation remedial approach in the area of composite sample S26, S27, S28. PHASE II EXCAVATION ACTIVITIES General Site Work A Site Health & Safety Plan (SHSP) was updated to accompany the field activities conducted at the site. The SHSP identified potential safety hazards to personnel working at the site. A geophysical subcontractor was used to clear the proposed excavation area of subsurface utilities. The proposed excavation area was marked in advance and USA North was notified, as required, so the member utility companies can mark their facilities within pertinent public rights-of-way and utility easements prior to our proceeding with the excavation program proposed herein. Remedial Excavation On May 1, 2014, Krazan's subcontractor, Williams Excavation of Fresno, California, completed an approximate 50 feet x seven (7) feet x two (2) feet deep excavation in the area of composite sample S26, S27, S28. Excavation was conducted using a Bobcat excavator. Six (6) confirmation soil samples, EX-1 through EX-6, were collected from the bottom and sidewalls of the excavation. The confirmation soil samples were analyzed for TPH-d and TPH-mo by EPA Method 8015C. The SJCEHD was on-site during excavation and confirmation sampling activities. — , Photographs of the excavation are included in Appendix B. The resulting exaction was backfilled using clean fill soil and was compacted to meet minimum engineering standards. 2 Formaldehyde Council, Formaldehyde: Facts and Background Information, November 2007, http://formaldehydefacts.orgi_base/pdf/fact_sheets/11_01_07-FormadehydeFactsandBackgroundInformation.pdf KRAZAN & ASSOCIATES, INC. With Offices Serving the Western United States Phase!! LSA - 014-13157 Excavation Report F1NAL.docx i\it, stA lvtcvli ev` / del)