THE Environment Agency is investigating after a boat sank in Strangford Lough containing up to 1,000 litres of diesel.
The vessel was reported to have been tied up at the quayside in Portaferry, Co Down for several months.
Ards and North Down Borough Council called in consultants to manage the diesel spill.
The Environment Agency said a water quality inspector has also been at the scene.
A spokesman said diesel spreads rapidly on water and the fuel will be dispersed by the wind and tides.
"The situation will be kept under review to determine if any remedial measures are necessary or practicable given the strong currents in the vicinity of Cook Street (by the quay)," he said.
It is feared the diesel spill could affect wildlife in the lough.
Exploris Aquarium in Portaferry closed its sea intake as a precaution.
The council said: "As a precaution Exploris has implemented contingency plans to protect the marine life in the centre and will continue to monitor the situation in liaison with the other agencies involved."
