EDINBURGH (Reuters) - An oil rig that ran aground off a Scottish island on Sunday may have leaked around 53 tonnes of diesel but has not caused any serious pollution, Britain's Maritime and Coastguard Agency (MCA) said.
The Transocean Winner rig broke away while being towed during a storm and became grounded off the northwestern Isle of Lewis.
"Aircraft yesterday flew over the location and surrounding area to make careful observations for pollution around the rig and the nearby coast and sea and no sheen or sign of pollution has been found," the MCA said on Thursday.
Diesel is much lighter than crude oil which is the cause of the worst slicks and the MCA said it posed "much lower environmental risks".
Two of four diesel fuel tanks on the rig were believed to have been damaged. The MCA is still monitoring the area and has set an exclusion zone of 300 meters around the rig.
Scotland's government said on Wednesday that the incident posed questions about why the rig - which was en route from Norway to Malta - was being towed through Scottish waters despite a forecast for stormy weather.
(Reporting by Elisabeth O'Leary; Editing by Robin Pomeroy)