Abandoned decaying oil tanker may explode, sparking environmental and

You are right (Except that it is Bbls. not Gls.):

PS> Being originally Steam Turbine she probably have a scoop inlet for cooling water. Another FSO with this arrangement flooded in the engine room while on location in Indonesia.
The scoop inlet had not been blanked off externally, thus allowing corrosion to cause leak(s) to develop over time.