We use 14 years of spaceborne SAR imagery from Sentinel-1A/B, ALOS-1/2 PALSAR-1/2, and Envisat ASAR to show that heavy fuel was leaking out of a ship wreck off the Bulgarian Black Sea coast. The oil spills were detected only in the summer months, when the sea bottom temperature exceeded 10 °C, indicating that the viscosity of the heavy fuel is too high at lower temperatures. Moreover, periods of high winds, hence of high sea state, were preceding each oil spill detecting, which indicates that mechanical action on the wreck's hull was needed to initiate further leakage.