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with paint and pavement nails for future reference. Montgomery Watson will measure distances from permanent site fixtures such as curbs, building and/or lot corners, and lightpoles so that a paper record is maintained. The subcontractor will then clear specific sampling locations along the sewer line or at the former dry cleaner identified by the Montgomery Watson project engineer. r 2.2 SAMPLING POINTS Soil vapor samples will be collected from locations on ASPI property along the sanitary sewer laterals identified in the geophysical survey, in the vicinity of the former Norge and Deluxe facilities, and near the property boundary adjacent to Service Dry Cleaners. For purposes of discussion, proposed sampling locations are presented on Figure 3. As depicted here, the sampling points will emphasize the most probable locations where VOCs may be encountered and will also follow the path of the sanitary sewer lateral,beginning with the most downstream location ' on the parcel owned by ASPI and progressing upstream. Sample locations may be adjusted according to conditions encountered in the field. Soil vapor samples will be collected nominally 5 feet below ground surface. The actual depths will be determined by the geophysical survey. Optimally, soil vapor samples will be collected 1-2 feet below the bottom of the sanitary sewer pipe and 4-5 feet below grade in the vicinity of former and existing buildings. "Hits" or detections of VOCs at relatively high concentrations (-50 ppb) in any given soil vapor sample will be offset laterally and vertically. The sampling point will be offset vertically in the same location by driving the probe deeper. The maximum anticipated depth of sampling will be approximately 15 feet below ground surface. "Hits" will also be offset laterally away from the iftitial sample within the limits of the parcel. Each offset is expected to be 10-20 feet, given other physical limitations on the site. If elevated concentrations of VOCs are encountered on the ASPI property, Montgomery Watson is prepared to continue the investigation into a second day. 2.3 METHODS AND PROCEDURES 2.3.1 Soil Gas Sample Collection Soil vapor samples will be collected by driving a small-diameter probe (5/8 inches outside diameter) equipped with a hardened reverse-threaded steel tip to the depths based initially on the identified depth of the sanitary sewer line. The probes will be driven by either a hydraulic hammer 5