SITE INFORMATION AND CORRESPONDENCE

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t _ Mr Jeff Cosgray and Ken - 2 - 18 March 2010 Mountain House Site#4 The KMEP Letter includes a memorandum prepared by a KMEP employee, which concludes that the existing evidence absolves KMEP from responsibility for the spill since (1) the materials identified in MH4-6 consisted of C11-C15 hydrocarbons while the KPL primarily transmits C4-C12 hydrocarbons, (2) benzene, toluene, ethylbenzene, and xylenes (collectively BTEX) and methyl tertiary butyl ether (MTBE), which are typical indicators of releases from KMEP pipelines, were present in low concentrations in MH4-6, and (3) the lateral distribution of the release is largely limited to MH4-6. A second memo dated 22 December 2009 and prepared by a KMEP employee states that internal inspections of the KPL, conducted in 2004 and 2009 in the vicinity of the spill, reported no anomalies that met Department of Transportation (DOT) investigation and repair criteria. KMEP does not believe additional investigation on its part is warranted at this time. The Chevron Letter generally drew a similar conclusion based on data presented to the Central Valley Water Board in previous reports. The Chevron Letter states that between 2001 and 2008, the BAPL transmitted mostly gasoline and diesel but no jet fuel. The results of a pipeline integrity report dated 24 January 2006 showed that the 6-inch line passed a 1 ,440 pounds per square inch (psi) tightness test. Figures from the Chevron Letter show that MH4-6 was advanced closest to the BAPL. However, the position of the BAPL shown in the Chevron Letter differs from KMEP's observations in the field in December 2009. The Chevron Letter states that gas chromatograph fingerprint analysis of the MH4-6 soil sample during a 2005 investigation showed that the sample consisted of 98% hydrocarbons in the CII-C20 range and that the presence of branched paraffins observed in the sample is not typical of jet fuel. Figure 5 shows that detections in a groundwater sample collected from 13 feet below ground surface (bgs) contained total petroleum hydrocarbons as gasoline (TPHg) at 2,400 micrograms per liter (pg/L), TPH as diesel (TPHd) at 130,000 pg/L, and TPHd with silica gel cleanup (TPHdsg) at 160,000 pg/L. There were also low level detections of benzene, ethylbenzene, and xylenes. Toluene was not detected. Page 3 presents Chevron's evaluation of the laboratory analytical results. The text states that the (1) weathering of a gasoline-impacted soil typically removes shorter length carbon chains, (2) the absence of benzene and toluene in the soil are not indicative of a gasoline release, and (3) the absence of carbon chain lengths greater than C15 indicates the contaminated soil is not due to a diesel fuel release. Chevron's evaluation states that the branched paraffins observed in the fingerprint analysis are not typically found in diesel fuel, which indicates that the MH4-6 hydrocarbons are most likely weathered jet fuel. Chevron concludes that soil and groundwater samples collected from adjacent borings laterally delineate the spill to a localized area and indicate that the hydrocarbons were not released from the BAPL. Our comments are presented below. 1 . To demonstrate to the Central Valley Water Board staff that additional investigation is unwarranted, Chevron and KMEP essentially presented again the same readily available information that the Central Valley Water Board staff used to determine