ExampleOne1

EXAMPLE NO. 1: FORENSIC STUDY AT A NORTHERN NEW JERSEY SERVICE STATION: THE MIXING OF OLD AND NEW GASOLINE

In 2000, a client purchased a gasoline service station in northern New Jersey. A few days after receiving possession of the property, he received a letter from a State regulatory agency informing him that an investigation surrounding a leaking waste oil UST was required. He was unaware that a waste oil UST had existed; automotive repairs were not part of his or the previous owner’s business and the previous owner had indicated in writing that there were no environmental problems with the property. The client complied with the directive even though responsibility lay with the previous owner. A monitoring well was installed and laboratory analysis of a ground-water sample revealed elevated concentrations of gasoline constituents such as BTEX and MTBE. Two additional wells were subsequently installed and similar results were found. However, separate-phase gasoline was not detected on the water table.

In 2005, a significant release of regular-grade unleaded gasoline occurred from the existing fiberglass USTs. About 0.5 foot (~0.1 m) of separate-phase gasoline was present on the water table beneath the site and at off-site, downgradient locations. A nearby nursing home and bar had to be evacuated because of gasoline vapours. Samples of separate-phase gasoline were collected from five locations: two on-site and three off-site. TEL was detected in one on-site and all three off-site samples. Furthermore, the TEL concentrations increased in the downgradient location.

Further investigation of historical documents, obtained from the state regulatory agency, revealed that a release of regular-grade leaded gasoline had occurred at this site in the 1970s. A pump-and-treat system had been present in 1978 to 1979 and several thousands of gallons of gasoline had been recovered. However, documental evidence for the appropriate closure of the cleanup was not found.