An oil spill off the west Cork coast has broken up into three smaller slicks and is moving eastwards, the Department of Transport said today.
Earlier reports indicated that up to 1,000 tonnes of oil spilled in an incident involving two Russian naval vessels on Saturday is expected to hit the South east coast of Ireland in 16 days time depending on weather conditions.
The Department of Transport said further overflights of the pollution site took place today, but it was too early to determine what impact the spill would have on the environment.
"At this point it is too early to accurately predict what volumes may come ashore and therefore what environmental, commercial and visual impact is involved," the Department of Transport said.
According to the latest estimates, some 522 tonnes of fuel oil have spread out in three distinct slicks 39 miles south of the Old Head of Kinsale.
The Department said the slick is breaking up, thinning and spreading over a larger area and moving eastwards, parallel to the coast about 30 or 40 miles out to sea.
Samples of the oil have been taken from the scene and brought to Waterford where they are beign sent for testing by a specialist laboratory in Scotland.
The incident occurred on Saturday when the two Russian vessels were attempting to transfer fuel from one to the other 80km (50 miles) south of Fastnet. The oil then spread over an area measuring 4.5km by 5km.
The spill did not happen in Irish waters but was within the zone around the Irish coastline being monitored for pollution by Irish authorities.
The Irish Coast Guard has contracted a Cork-based tug to go out to the spill and evaluate the possibility of cleaning it up at sea. Oil coming ashore on the South east coast will be recovered mechanically by local authorities with assistance from the Coast Guard who will oversee the operation.
The coast guard is briefing various Government departments and agencies today to outline the current situation and the potential impact to the coastline and marine environment.
The Russian Naval Attache confirmed an internal investigation is being carried out into the cause of the incident. The Russian embassy has been asked to supply samples of the oils carried onboard the Russian vessels and for oil characteristic data sheets.
Labour party spokesperson on the Marine Senator Michael McCarthy said Minister Noel Dempsey needed to take a more hands-on approach to managing the situation.
"When news of this oil spill first emerged, we were given to understand that there were about 300 tonnes of oil in question, and that there was little or no risk that it would impact on our coastline," he said.
"Now it appears that there was more like 1,000 tonnes of oil spilled, and that the slick could very well make landfall along the southern coast, with Wexford particularly vulnerable."
He called on Mr Dempsey to produce a risk assessment report as a matter of urgency.
"Communities along the South Coast, particularly those that are dependent on fishing or on maritime tourism, are entitled to know what the chances are that their area will be affected, so that they can take the appropriate preventative measures," he said.