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On June 29, 1995, Groundwater Technology, Inc (GTI) published Environmental Assessment Report documenting the installation of two vapor extraction well nests (VW-1 and VW-2) and two single vapor extraction wells (VW-3 and VW-4), and the pilot testing and modeling of soil vapor extraction Based on their findings, GTI recommended that the site be remediated by soil vapor extraction plus air sparging from MW-1 By January 1996, the groundwater table had risen above the top of the screen interval in all five groundwater monitoring wells, and had entered the screen interval of the two deeper soil vapor extraction wells (VW-1 D and VW-21D) Coincidentally, from July 1995 to April 1996, groundwater ' samples collected on four quarterly occasions from the five monitoring wells did not contain detectable concentrations of TPH-as-gasoline In August 1996, sampling of the five original monitoring wells was discontinued and the sampling of the two deeper vapor extraction wells (VW-1 D and VW-2D) was initiated Groundwater samples collected from VW-1 D and VW-2D contained detectable concentrations of TPH-as- gasoline, benzene, and methyl tertiary butyl ether (MTBE) ' On April 28, 1998, Ramage Environmental installed two additional groundwater monitoring wells (MW-6 and MW-7) to re-establish a groundwater table monitoring and sampling capability at the site Since the installation of these new wells, groundwater has been monitored and sampled on a quarterly basis from MW-6, MW-7, VW-1 D and VW-2D ' From June 1999 through June 2000, ENSR Consultants operated a soil vapor extraction system at the site Initially, ENSR extracted from VW-11D, VW-IS, VW-2S, VW-3, and VW-4 After several months of operation, air sparging was initiated in MW-1 According to ENSR, the remediation system removed over 7,000 pounds of gasoline hydrocarbons from the subsurface In July 2000, ENSR decommissioned the system and removed the equipment from the site I I I 4