During litigation between a western railroad and its insurance carriers, a Roux Associates Principal Hydrogeologist was retained by a group of insurance carriers to evaluate the timing of a historical release of TCE at a rail yard. This release impacted both soil and groundwater, causing a TCE plume in groundwater that extended several miles off-site and was estimated to cost $50 million to remediate.

The Roux expert used three lines of evidence to show that the release of TCE was associated with a vapor degreaser that operated between 1968 and 1979. The three lines of evidence were chemical breakdown data, groundwater modeling, and historic aerial photographs. 

In combination, these three lines of evidence showed definitively that the pre-1968 insurance policies were not in play to address the costs of remediating groundwater affected by discharges from the vapor degreaser, because the degreaser was not in place prior to 1968.