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me N%041 .BP Chemical, Advanced Materials Div., P.O. Box 6189, Stockton, CA October 20, 1992 Mr. Lon Kitagawa 2 SCOPE OF WORK The following section describes the work activities planned to complete the corrective actions. Following the completion of these tasks, Groundwater Technology will request site closure from the SJCEHD. Health and Safety Plan The existing site specific Health and Safety Plan (HSP) will be reviewed and revised as appropriate before conducting the planned field activities. That current plan was developed according to Occupational Safety and Health Administration (OSHA) Standard Waste Operations and Emergency Response guidelines (29 CFR 1910.120). The SJCEHD has already reviewed and approved the existing HSP that was required for the previous site assessment activities. Because site conditions have not changed since the site assessment was conducted, only minor modifications to the existing HSP will be required. Groundwater Technology personnel, subcontractors, and any person entering the job site will be required to read and sign the HSP before performing field activities. Soil Excavation The former UST excavation will be further excavated to remove soil containing residual concentrations of petroleum fuel hydrocarbons. The excavation will be extended using a backhoe (Case 550). Based on results from soil samples collected from borings SB-1 and SB-2, and grab samples 1 through 9 (see Figure 1), the excavation will be extended approximately 2 to 3 feet on the south end of the excavation. In addition, because the sample from the bottom of the excavation (Sample #2) contained detectable concentrations of petroleum hydrocarbons, the former excavation will be extended approximately 2 to 3 feet deeper in the southern end. Because results from soil samples 1, 3, 5, and 6 reported detectable concentrations of toluene, minor additional excavation along the north, west, and east sides of the excavation will also be required. The additional excavated soil will be placed in stockpiles adjacent to the excavation. All stockpiled soil will be covered with polyethylene plastic sheeting until that soil has been characterized, and removed from the site for off-site disposal. Based on the results from the site assessment, approximately 150 cubic yards of soil will be excavated during these corrective action measures. After the excavation has been extended as described above, soil samples from the excavation sidewalls and bottom will be collected and analyzed by the on-site mobile state-certified laboratory as described below (Sections 2.3 and 2.4). If the analytical results indicate that the sidewali and bottom soil samples do not contain concentrations of total petroleum hydrocarbons-as-gasoline (TPH-G) exceeding 50 parts per million (ppm) and benzene concentrations exceeding 1 ppm, further excavation will not be required, and the excavated pit will be backfilled as described below in Section 2.5. If the analytical results indicate that the sidewail and bottom samples contain TPH-G and benzene concentrations exceeding 50 �LJLJ''i GROUNDWATER ��`�TECHNOLOGY,INC.