Salvage experts fear that tonnes of diesel has leaked into the Atlantic after a drilling rig ran aground, breaching its fuel tanks, in the Western Isles of Scotland earlier this week.

The specialists believe two of the four fuel storage tanks on the Transocean Winner platform were damaged as well as water stability tanks, when the 17,000-tonne rig crashed into rocks near Carloway on the Isle of Lewis in a heavy storm.

The platform, which ran aground close to Dalmore beach, a popular surfing spot, was carrying 280 tonnes (70,000 gallons) of diesel, but there has been no sign so far of an oil slick or other visible evidence that fuel was still leaking into the sea.

Hugh Shaw, the UK government’s representative for maritime and salvage, said a Maritime and Coastguard Agency spotter plane was now scouring the area south of the rig for signs of a slick, but nothing had been seen or smelt since Monday. He said that suggested any fuel leak happened as the rig, which was unmanned at the time, first hit the rocks. It is unclear how much diesel has escaped.

“We’re not getting any reports of anything or that anyone is seeing anything,” Shaw said. “It may well be that if the tanks have been breached, and we’ve lost the contents, it might well have been lost on Monday morning in the adverse weather when the installation ran ashore.”

Shaw disclosed that it could be several months before the rig, which was being towed from Norway to Malta when a tow rope snapped during a gale at about 4.30am on Monday morning, could be removed.

The breached tanks were detected by a team who spent three-and-a-half hours on the platform on Tuesday, using sounding pipes to test how much oil and ballast was in each tank.



A plan to winch a larger inspection team down on to the rig on Wednesday morning, to continue those investigations over a full day, were scuppered because the wind was not strong enough to give the helicopter the right flying conditions for a safe operation.

The forecast shows the weather is likely to worsen greatly for the next four days, further hampering the investigation, Shaw said. “We do know from the forecasts we’re getting from tomorrow, it’s going to start deteriorating,” he said.

Speaking from Lewis, where he is overseeing the salvage operation, Shaw said that the salvors and Transocean, the rig’s owners, had to establish what kind of repairs were needed to seal up the ballast tank and oil tanks to make sure it was seaworthy. “Where she’s sitting, that could be very difficult,” he warned.

They needed to get the right barges on site and wait for a clear weather window before attempting to pull it clear. “We’re certainly not talking days. We might not be talking weeks; it may be much longer than that” before the rig could be refloated, he said.

The incident is now under investigation by the Marine Accident Investigation Branch, with two tugs on standby, including the MCA’s emergency tug ETV Herakles.

The Maritime and Coastguard Agency has imposed a 300-metre exclusion zone around the site, to prevent onlookers hampering the salvage teams and emergency services, and to stop onlookers venturing onto cliffs close to the beached rig.

The disclosure of the suspected leak added further urgency to questions from the Scottish government and conservationists about the decision to tow the vessel during a storm, and the UK government decision to scrap an emergency tug based in Stornoway on Lewis in 2012.

Dr Richard Dixon, the director of Friends of the Earth Scotland, said the leak could pose a serious threat to local wildlife, including whales, dolphins and seabirds. Seven miles west of the grounding site was EU-protected Loch Roag coastal lagoons system.

The risks posed to the marine environment by oil installations was likely to increase, with further decommissioning of rigs due soon and climate change certain to increase the severity and unpredictability of violent storms in the Atlantic.

“If the diesel oil leaks into the environment, the clamour for answers as to why such a risky trip was attempted will grow much louder,” Dixon said. “Why was the rig taking this dangerous route off the mainland in such a storm? How do we make sure that companies don’t repeat these mistakes?”

Roseanna Cunningham, the Scottish environment secretary, said her government was already pressing the UK government for information on why the Transocean Winner was allowed to transit UK waters when a storm had been forecast.

“Although the diesel is expected to rapidly disperse in the current sea conditions, the environment group, which is chaired by [the government agency] Marine Scotland, has put in place measures to swiftly identify any potential environmental impact on this precious and fragile marine habitat,” she said.