The US (P) alleges that the Point Breeze oil refinery, owned by Sunoco (Ds) at various points in time, caused underground petroleum pollution to an adjacent military supply depot called the Defense Supply Center Philadelphia. The property is currently used as a civilian shopping mall called “Quartermaster Plaza.” P first detected contamination in 1987 from a fuel leak from a United States gas station located on the property itself. When P investigated the pollution, it found “widespread petroleum contamination” that could not have come from the gas station. In 1995, one such study concluded that Point Breeze was the most likely source of the contamination. P has incurred $22,000,000 in cleanup costs. The United States sought cost recovery under the Tank Act which includes the right to cost recovery and diminution of property value. P has filed a Motion for Order on Applicability of Statutes of Limitations, seeking a ruling on only the legal question of which statute of limitations applies. P argues that no statute of limitations applies, or that the Pennsylvania twenty-year Tank Act limit applies.