SITE INFORMATION AND CORRESPONDENCE FILE 2

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Messrs Larson and TrommE _ June 14, 2010 April and May 2010 Draft Five-Year Review Page 3 of 4 Recommendation Various Sites fully addressed on a technical level. Intuitively, the EHD agrees that vapor intrusion from impacted soil and groundwater on a gasoline service station site would seem to be of minimal concern compared to fugitive gasoline hydrocarbon vapor released during the fueling operation or automobile maintenance. However, the EHD is responsible for overseeing all aspects related to the investigation and cleanup of unauthorized releases from the UST systems, and not for spills and releases from the fueling or automobile maintenance operations. The EHD has tried, but could not identify a guidance document, State Board Order or regulation that establishes omitting vapor intrusion evaluation at an active service station as a proper standard of practice. The fourteen cases closed by State Board Orders did not involve vapor intrusion evaluations; and while some of the sites closed by the State Board through Resolution 2010-0006 did have various unresolved vapor intrusion evaluation issues, the web page for State Board Resolutions, Orders and Decisions specifically notes that Resolutions are not precedential. The EHD will continue to look into this issue, and is receptive to guidance from the CUF and/or State Board as such a standard of practice will greatly assist the EHD getting site cases closed. The EHD intention is to continue with the soil vapor survey or other adequate form of vapor intrusion evaluation pending further guidance on the issue. 425 W. Larch Road, Tracy, CA; Claim Number 13849: The CUF recommended the EHD to require submittal bf the oxygen injection and dual phase extraction pilot test reports. Neither the bench scale test nor the pilot test was ever conducted and the responsible party (RP) has changed consultants. The new consultant has prepared a site conceptual model and proposed that a corrective action plan (CAP) be prepared. The new consultant also proposed additional site assessment in the source and down-gradient areas, and installation of a down-gradient well to delineate the extent of the dissolved plume; proposals the EHD has approved. 244 W. Harding Way, Stockton, CA; Claim Number 16139: The CUF recommended that the EHD consider this site for closure; such consideration is in progress. By letter dated April 14, 2010, the EHD directed the RP to conduct a groundwater monitoring event and submit a soil vapor intrusion evaluation. Anticipating favorable results, the EHD will direct preparation and submittal of a site closure summary report. 4100 E. Fremont Street, Stockton, CA; Claim Number 13651: The CUF concurs with the site closure process in progress for this site. The EHD is awaiting a site closure summary report and will respond appropriately to it when received. If the report is not received soon, the EHD will issue a 30-day letter directing it submittal. 444 W. Mossdale Road, Manteca, CA; Claim Number 14118: As with the case for the site at 15 E. Grant Line Road, the CUF offered an opinion that the vapor intrusion evaluation concern for this site is unnecessary and (not) appropriate as the site is an active retail gasoline station and the CUF recommended that the EHD consider this site for closure. For the same reasons stated in the EHD comments for the 15 E. Grant Line Road site concerning the vapor intrusion issue, the EHD had directed clarification of several problems identified by the EHD with the original vapor intrusion evaluation. A closure summary report addendum, dated May 4, 2010, but submitted to GeoTracker May 30, 2010, is anticipated to address the EHD concerns and will be reviewed shortly. If the addendum is found to be adequate, the closure process will be initiated. April and May 2010 Annual 5-year Reviews Vickie's Sites.doc