SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Mr. Carl W. Knowles, Successor Trustee Page 2 of 5 Knowles Family Trust 23 December 2009 Former Roek Construction 102 S. Wilson Way The RCC also discusses trends in contaminant concentrations over time, arguing that the trends demonstrate that migration of the contaminants from an offsite release onto your site occurred. Finally, you present in the RCC a discussion of the State Water Resources Control Board Order WQO 2004-0005, comparing the circumstances of that case with yours, and you included a copy of the final WQO-2004-0005 and an apparently draft form of the order. The EHD has reviewed and considered the RCC and WQO-2004-005 in regard to your formal request that the EHD issue you a "No Further Action" letter with respect to the site located at 102 S. Wilson Way. Primarily for reasons cited below, the EHD has decided that it cannot concur with your request, and will not issue a "No Further Action" letter at this time. This decision is subject to appeal to the State Water Resources Control Board (State Water Board), pursuant to H&SC Section 25296.40 (a) (1), (Thompson-Richter Underground Storage Tank Reform Act — Senate Bill 562). Please contact the State Water Board Underground Storage Tank Program at (916) 341-5752 or visit the State Water Board internet website at htta://www.waterboards.ca.aov/ust/cleanup/petitions.html for information regarding the appeals process. The EHD cannot comment in detail on some of the points put forth in the RCC as they rely on interpretations and/or opinions of a geological or civil engineering nature, which can only be presented to the EHD in a report prepared by or under the supervision of a qualified and licensed geologist as set forth in Chapter 12.5, Section 7800 et seq, Geologist and Geophysicist Act of the Business and Professions Code. Section 7838 exempts professional civil engineers from registration under the Geologist and Geophysicist Act so their signature on plans, documents or reports would also be acceptable as far as the professional work is related to the practice of civil engineering. The EHD responses to other points raised in the RCC are as follows: The EHD believes that the data acquired from soil and groundwater samples collected from your site amply demonstrate that an unauthorized release or releases from the underground storage tank (UST) system formerly located on your site has impacted groundwater. Soil samples collected between 5 feet and 25 feet below surface grade (bsg) from boring TB-5, between 15.5 feet and 40.5 feet in boring VW-4/5, between 25.5 feet and 55.5 feet bsg in boring VW-1/2, between 45 feet and 60 feet bsg in boring CB2, between 55 feet and 70 feet bsg in boring CB-1, and between 75 feet and 95 feet bsg in boring CB-1A have been significantly impacted by total petroleum hydrocarbons quantified as gasoline (TPHg), and variously impacted by benzene, toluene, ethylbenzene and total xylenes (BTEX). The borings yielding the impacted soil samples are in the general former UST system area; soil samples from borings advanced further toward the south (MW-4 and MW-7) and toward the east (MW-13 and MW-5), yielded soil samples that were not significantly impacted by contaminants between 10 and 55 or 60 feet bsg. The centralization of the impacted soil borings in the former UST system area with outlying un- impacted soil borings is very suggestive of the soil impact originating from the former UST system; the occurrences of thick vertical sections of soil at varying depths in the different impacted borings seems consistent with a plume of hydrocarbons descending through the soil column until encountering an interval of reduced permeability, causing the hydrocarbons to then Site Closure Request Response 1209