A small amount of oil is reported to be leaking onto beaches in the Shannon Estuary after a tanker capsized in Foynes harbour in Co Limerick this morning.
One man was thrown into the river when the ship listed over. There were no other injuries and all other crew were taken ashore without incident.
The ship, a 5,000 tonne heavy-lift semi-submersible, is used for carrying other boats or equipment.
It is understood the vessel capsized while in the process of loading a dredger aboard. It is now resting on the bed of the river.
There were up to 11,000 litres of fuel oil aboard, according to reports.
A Coastguard marine pollution expert has flown to the area to assess the scale of the risk to the environment following the incident and to formulate a response in conjunction with the port authorities and Kerry and Limerick county councils.
It is hoped divers will be able to reach a hole from which the oil is thought to be leaking at low tide later this evening.