SITE INFORMATION AND CORRESPONDENCE_FILE 1

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r *4WO Thomas Berg AN1Mo1dMi11HRAwrkP1n June 16.2005 Page#2 Document(s) Reviewed American Moulding and Millwork Company, Stockton, Cafifornia: Supplemental Site Assessment and Comprehensive Risk Assessment Work Plan. The report was prepared by MACTEC Engineering and Consulting Inc, Petaluma, California. The document was dated April 21, 2005. Scope of Review The work plan report was reviewed and evaluated for scientific sand technical contents only. Any grammatical or typographic errors which did not affect the interpretation of data were not noted. Previous reports relating to this facility were not consulted during the evaluation of the referenced worm plan document. Comments Section 3.2, Analytical Approach: HERD recommends the use of USEPA Method 8310 for the specific analysis of polynuclear aromatic hydrocarbons (PAH s) or USEPA Method 82700 for exclusive PAH analysis using selective ion monitoring, in addition to analysis for semi-volatile organic chemicals. Section 4.1 —Areas of Concern Recommended for NO FURTHER ACTION: The ADCs which have been listed for "No Further Action" are: Pentachlorophenol Area, Underground Storage Tanks, Septic Tanks, and Polychlorinated Biphenyl Containing Transformers. HERD does not agree to the proposed "No Further Action" for the specific AOCs because a comprehensive and quantified rationale has not been adequatety presented. "No Further Action" would imply that the recommended areas for such a risk management decision have been evaluated on risk-based criterion (cumulative risk determined on multi-pathway and multimedia approach) or that the chemicals of potential concern (COPCs) have been demonstrated to be below practical quantitation limits (PQLs) of the analytical methods that were employed to analyze the full profile of the contaminants. Furthermore, COPCs can not be excluded from risk- based process merely because they are at or below the USEPA Region IX Preliminary Remediation Goal (PRG) values. For the reasons and explanations provided above, the ADCs proposed for "No Further Action" do not comply with the required standards and criteria, and should be added to the work plan for supplemental investigation and risk assessment. Section 5.4 Comprehensive Risk Assessment Work Plan HERD has noted that the work plan is submitted on the proposed residential land use scenario (unrestricted land use). It is also stated under Section 5.1.2: Objectives that "the areas of the property not used, comprising 40 acres are to be addressed.' HFRD assumes that these areas are in addition to the AOCs identified and listed in the worm plan report and will be subjected to site characterization and included in the site- wide risk assessment process.. Furthermore, HERD requests that all the areas that