In early 1998, a catastrophic release of JP-4 jet fuel occurred from a subsurface fuel loop. A helium test method was selected to investigate the lines because of its cost-effectiveness, accuracy, and safety. Two leaks were discovered prior to excavation being conducted. Further understanding of the subsurface geology and construction of the fuel lines allowed the apparent wide distribution of jet fuel in the subsurface. The leaks were excavated and repaired. The system was leak tested using a pressure/volume method after repair to ensure all repairs were made successfully. The total cost to investigate and repair the system was $500,000 versus an initial estimate of $6 million if excavation and replacement had been conducted.