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Hamilton Body Shop /Hamilton Towing March 27, 2012 Page 5 of 10 regulatory and /or emergency response officials may also be interviewed regarding knowledge of past or present environmental problems or emergency responses at the site. IDENTIFICATION OF DATA GAPS Depending on the availability of certain resources for evaluating historical property use, previous property owners (for interview) and other pertinent information; certain "Data Gaps" may be identified within our Report. Wightman Petrie will make determinations as to the potential impacts such Data Gaps have on conclusions as to the presence or potential presence of recognized environmental conditions. PHASE I ENVIRONMENTAL SITE ASSESSMENT UPDATE REPORTING Upon completion of our site reconnaissance, regulatory database and historical records review, a verbal summary will be presented. Our written report of findings will include documentation to support the analysis, opinions and conclusions found in the report, inclusive of referenced sources. Based upon the observations made during the Phase I reconnaissance, modifications to the Phase II Proposed Scope of Services may be warranted. TASK 2 — Ground Penetrating Radar Prior to the initiation of any Phase II Environmental Site Assessment activities, Wightman Petrie proposes to conduct a Ground Penetrating Radar Survey of the 802 -812 S. Lafayette Blvd. property, as well as the 901 -917 S. Lafayette Blvd. property for the purpose of determining whether UST systems remain in the ground. As indicated from the prior Phase I Site Assessment Reports, the removal status of certain historical UST systems could not be verified, and at least one (1) additional UST system is thought to remain in the ground (as indicated by the presence of a vent pipe on the side of the building at 901 -917 S. Lafayette Blvd.). Ground Penetrating Radar (GPR) offers the means to detect buried objects that are not otherwise detectable. In addition to the ability to locate metal objects (i.e., underground storage tanks, drums), GPR is able to detect non - metallic objects. The system sends radar pulses into the surface, receives, and processes the reflected energy. Through advanced processing technology, the system calibrates the di- electric constant of the surrounding material. When the signal is reflected from the material having a different di- electric constant, the signal is displayed on the screen as an anomaly. Depth can also be determined by processing the sampling interval and determining the size and comparing relative data to other objects detected. Characteristics of underlying soils effect the penetration of the radar through the ground. Sands and gravel offer the greatest depth penetration and clearest resolution. Whereas, dense saturated clays offer limited penetration of the radar signal. For purposes of this proposal, Wightman Petrie has assumed a depth limitation for the GPR of approximately 8 feet below land surface. Areas of the suspect former UST system location(s) will be scanned by GPR and delineated using varying interval grid patterns. Multiple scans in a north -south and east -west direction will be performed utilizing the GPR, looking for anomalies. Any identified anomalies (i.e., disturbed subsurface soils) will be marked on the surface using paint, as appropriate for utility locators and for soil boring locations by Wightman Petrie. TASK 3 - Soil Sampling via Geoprobe Methodology Using Geoprobe methodologies (small track mounted hydraulically driven sampling probe) soil samples will be collected from a total of nineteen (19) locations. Boring locations will be determined based upon the results of historical document review and field data gathered from the prior Phase I Site Assessments, Phase I Updates and completion of the Ground Penetrating Radar Surveys. In general, Wightman Petrie would propose to install at least four (4) soil borings across the 802 -812 S. Lafayette Blvd. property, with specific emphasis on the area of former USTs and stained soils associated with releases from wrecked