Fuel in small amounts has been found in tanks belonging to the grounded cargo ship, MV Alta, but there is no cargo on board.
That is according to an initial report by marine contractors who boarded the vessel at low tide this morning.
It followed a request from Cork County Council and the Irish Coast Guard.
The 80-metre vessel ran aground west of Ballycotton, Co Cork during Storm Dennis on Sunday.
It had been drifting in the Atlantic for more than a year after it was abandoned by its crew.
RTE News has more here to report on the grounding.