Washington Post | Coast Guard identifies oil in refuge and river as fuel oil; source still unknown Washington Post The oil that leaked into the waters of a waterfowl sanctuary and the Potomac River last week was fuel oil, similar to home heating oil, officials investigating the spill said Monday, but they do not yet know its source. The incident commander of a ... Coast Guard: Fuel oil in Potomac evaporating on its own Coast Guard: Dye Test Aims to Find Potomac Oil Sheen Source Coast Guard: Fuel oil was substance that spilled in Potomac |