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' Emergency Remediation - 2480 Tracy Blvd., Tracy, CA. • Page 3 INITIAL RESPONSE On the same day that the contamination was found in the subsurface beneath the site, Mr. Sanchez retained The San Joaquin Company Inc. to evaluate the extent and characteristics of the subsurface contamination and to develop a plan for management of the affected soil and groundwater. Mr. H. B. Dietz of The San Joaquin Company immediately travelled to the site and made a preliminary evaluation of the extent and characteristics of the subsurface contamination ' that was exposed in the basement excavation. Based on visual and olfactory indictors, he concluded that the groundwater and the soil in a zone from approximately one to two feet above the water table to an indeterminate depth below the water table were affected by fuel hydrocarbons. He preliminarily identified these as gasoline that appeared to be free of components of heavier fuels or other contaminants. After completing the preliminary evaluation, Mr. Dietz recommended that the general and sub-contractors secure the site and demobilize until the extent of the subsurface contamination.could be more completely evaluated and an emergency remediation plan developed. The objectives of the plan would be to permit early resumption of construction so that successful completion of the redevelopment of the site would not be put at risk due ' to prolonged delay or cost overruns that might exceed the financial resources available for construction, or otherwise jeopardize the project. The San Joaquin Company then contacted the SJCPHS on Mr. Sanchez's behalf to notify that agency of the discovery of soil and groundwater affected by gasoline in the subsurface beneath the 2480 Tracy Boulevard property. Ms. Linda Turkatte, REHS of the SJCPHS responded to the call for assistance and an on- site meeting was arranged for the next day, April 3, 1996. First Samples of Soil and Groundwater On April 3, 1996, following a site inspection by Ms. Turkatte, an excavator was used to dig test pits in the floor of the partially completed basement excavation. Samples designated TP-1 and TP-2 were recovered from the bottoms of these pits by raising a block of soil to the surface in an excavator bucket, cutting the face of the block with a knife to expose an undisturbed surface, and driving a clean, 2 in.-diameter by 4 in.-long brass sampling tube into the cut face until the tube was completely filled with soil. Sample TP-1 was recovered from a depth of approximately 8.9 ft below the pre-excavation elevation of the surface of the site. Sample TP-2 was recovered from approximately 8.5 ft ' below the pre-excavation ground surface. The plan locations of the previously-installed dewatering sump and the test-pits are shown on Figure 2.