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Chevron Environmental • M.Scott Mansholt • r'� r . ", Y'I J 11 <br /> Management Company Senior Environmental Project Scientist ��,1J�L, t Clo <br /> Property Management <br /> 6001 Bollinger Canyon Road SEP 2 7 2004 <br /> P.O.Box 6012 <br /> San Ramon,CA 94593-0712 ENVIRONMENT iiEALTH <br /> Tel(925)942-1804 <br /> Fax(925)842-0213 PERMIT/SERVICES <br /> ChevronTexaco <br /> September 17,2004 <br /> Mr.C.Dean Hubbard <br /> California Regional Water Quality Control Board <br /> Central Valley Region <br /> 1685 E Street <br /> Fresno,California 93706-2020 <br /> Response to Mr.Scharff's May 7 &September 8,2004 Letters <br /> Lyoth Loading Station <br /> 26501 Banta Road <br /> Tracy,California <br /> Dear Mr.Hubbard: <br /> Chevron Environmental Management Company (ChevronTexaco)has reviewed a copy of Mr. Jeffory <br /> J.Scharff's May 7 and September 8,2004 letters(attached)addressed to you and to Mr.James <br /> Carlisle of the Office of Environmental Heath Hazard Assessment(OEHHA), and to ChevronTexaco, <br /> respectively. Mr. Scharff is legal counsel for the Hoffman Brothers who own the property where <br /> ChevronTexaco's predecessor operated the former Lyoth Loading Station (site). ChevronTexaco <br /> would like to respond to comments made by Mr. Scharff. <br /> ChevronTexaco is currently working with the California Regional Water Quality Control Board— <br /> Central Valley Region(RWQCB)to evaluate the potential risk to human health from residual crude <br /> oil due to site operations. ChevronTexaco is willing to work with the Hoffman Brothers to take <br /> appropriate risk management measures based on their specific development plans for the site. <br /> The site has undergone previous environmental investigations. The environmental data were <br /> evaluated for a future residential land use scenario by Geomatrix Consultants,Inc. (Geomatrix) on <br /> behalf of ChevronTexaco,as summarized in a human health risk assessment(HHRA)1. The <br /> theoretical excess cancer risk for the site was below 10'6 except at two locations,boring GP-3 and the <br /> pipeline area,where the excess risk was estimated to be 2x10-5 and 7x10"6,respectively. The HHRH, <br /> including the data used to support the conclusions,was reviewed by OEHHA on behalf of the <br /> RWQCB and approved on April 18,2003. James Carlisle,D.V.M.Chief of OEHHA issued a final <br /> memo on April 18,2002'(attached)to the RWQCB that stated: <br /> '...that the risks in the GP-3 and pipeline areas are within acceptable range is a <br /> value judgment, and that 10'6 to 10-4 is not necessarily an acceptable range. <br /> According to the National Contingency Plan, risks below 10-6 are generally <br /> acceptable. Risks greater than 10-4 generally require remediation, and between 10-6 <br /> 1 Geomatrix,2002,Follow-up to Meeting on January 16,2002 and Addendum to Health Risk Assessment, <br /> Former Lyoth Loading Station,Tracy,California,February 26. <br /> '-OEHHA,2002,Response to Comments on the Health Risk Assessment,Former Lyoth Loading Station, <br /> Tracy,California, April 18. <br />