The Maritime and Coastguard Agency (MCA) has today confirmed that the oil rig that ran aground on the Western Isles could have lost almost one fifth of the diesel it was carrying.
But the agency insisted that no pollution had been detected in the area around it.
MCA is carrying out continual observations on scene and the agency’s counter pollution surveillance aircraft yesterday flew over the location and surrounding area to check for pollution around the stranded rig and the nearby coast and sea.
And the agency has now confirmed that “no sheen or sign of pollution” has been found.
The 17,000 tonne Transocean Winner rig grounded at Dalmore beach, near Carloway, on Lewis, on Monday after it broke free from its tug in rough seas.
The semi-submersible rig, which was reported to be carrying 280 metric tonnes of diesel oil, remains in its original position.
And teams from Smit Salvage and Transocean will continue inspections on board this week.
An MCA spokeswoman said: “Salvors identified two of the four diesel fuel tanks on the rig appear to have been breached.
“It is estimated that the maximum amount of diesel which could have been lost from those tanks is 53 tonnes and salvors will determine the quantity of diesel remaining in those tanks during the course of the salvage operation.
“Diesel is a light and non persistent oil which presents much lower environmental risks than heavy black crude oil.”
She added that additional salvors and technical experts from Transocean and equipment continued to arrive at the incident area to support the operation.
A temporary exclusion zone of 330 yards to keep boats away remains in force.
And the tug Union Bear remains in the vicinity along with the Emergency Towing Vessel Herakles, which is funded by the UK Government to support the operation.
Hugh Shaw, the Secretary of State’s representative for maritime and salvage continues to monitor the operations and is maintaining contact with everyone involved, including Transocean, Smit Salvage, the Scottish Environment Group and Western Isles Council.