ARCHIVED REPORTS_2011 REVISED FEASABILITY STUDY

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Nestle USA, Inc.—Ripon, CA January 28, 2011 2011 Revised Feasibility Study process at the Site until 1986, when a water extraction process replaced the methylene chloride process. 3.2 Discovery of Initial Release Two onsite production wells (N-1 and N-2) supplied water for the former facility's manufacturing processes. In January 1986, routine sampling and analysis of N-1 and N-2 revealed TCE in groundwater beneath the Site. Following notification to regulators, a granular, activated carbon (GAC) system commenced treatment operations at well N-1 in July 1986. In May 1986, TCE and its associated byproducts (the COCs) were detected in municipal wells MW-1 and MW-6, which were operated by the City of Ripon and were located near the Site. Subsequent to these findings, groundwater extraction at well MW-1 was terminated and the well was abandoned. 3.3 Regulatory Oversight The RWQCB is the primary agency with jurisdiction over this project. The RWQCB sets regulatory requirements for the Site and approves all plans and submittals. Other regulatory agencies with oversight authority include the San Joaquin County Environmental Health Department, the Stanislaus County Department of Environmental Resources, the San Joaquin Unified Air Pollution District, and the City of Ripon. 3.4 Remedial Actions Taken To Date This section presents an overview of past remediation activities and the results of those remediation activities including: • Soil Vapor and Soil Remediation, • Groundwater Remediation, and • Source Area Remediation. Remediation efforts have targeted removal of COC masses in soil, soil vapor, and groundwater. The following paragraphs summarize these efforts. Attachment A.1, Attachment A.2, and Attachment A.3, provide a detailed review of previous technologies and remedial approaches applied or tested at the Site. 3.4.1 Soil Vapor and Soil Remediation Prompted by the results of soil gas surveys conducted in 1987, 1989, 1991 and 1995, three different phases of soil vapor extraction (SVE) worked to remediate soil and soil vapor impacts to the vadose zone at the Site and at the Stockton Avenue location. These activities mitigated the migration of residual TCE into groundwater and reduced potential indoor air vapor intrusion into the buildings located above the impacted areas. Based on the 1987 soil gas survey results and a pilot test', five SVE wells were installed along with an SVE system at the Site. Based on 1989 and 1991 soil 4