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WORKPLAN FOR SIERRA LUMBER SITE 375 West Hazelton Ave., Stockton SITE DESCRIPTION The site has a lumber manufacturing business on it, located in the topographically flat, commercial/residential area of central Stockton. The former Underground Storage Tank (UST) area is located on the south westerly side of the building, under a shed like roof located behind the warehouse facing Hazelton Avenue, with the closest cross street Lincoln Road. Figure 1 presents the location of the proposed boring on the site. The site is underlain by the Calaveras River Alluvium which is part of the regional Quaternary-age Modesto Formation. Regionally, this unit ranges from clays to gravels, however only silt and clay were reported as being encountered during the Underground Storage Tank (UST) removal. During normal rainfall years, depth to groundwater is estimated to be approximately 35 feet below the ground surface. PREVIOUS INVESTIGATION The UST was removed from this site on August 1, 1988 . The 1000 gallon tank contained unleaded gasoline. Soil samples collected from the bottom of the excavation were analyzed for Total Petroleum Hydrocarbon as gasoline (TPHG) ; Benzene, Toluene, Ethylbenzene and Xylene (BTEX) . The soil samples taken below the UST in native soil showed 790 and 1200 parts per million (ppm) TPHG at 9 and 15 feet. Soil was excavated to about 15 feet and aerated. The excavation was filled in with clean soil. PROPOSED INVESTIGATION AND WORKPLAN The previous investigation results indicate the soil on this site is contaminated with TPHG and BTEX. John P. Cummings and Associates (JPCA) , therefore, proposes to characterize the vertical extent of the soil contamination. The proposed tasks of the investigation are listed below: 1) Prepare a site health and safety plan. Contact U S Alert. 2) Notify the San Joaquin County Environmental Health Division (SJCEHD) 48 hours prior to initiation of field work.