The BBC understands workers were told ‘this is not a drill’, before being evacuated
26 March 2012 Last updated at 20:18
Elgin platform gas leak: Shell evacuates Shearwater.
Oil workers have been removed from a second platform and drilling rig in the North Sea because of safety concerns.
A gas leak near a rig 150 miles (240km) off Aberdeen led to the evacuation of the Elgin platform on Sunday.
Now Shell has moved 85 non-essential staff from a nearby platform Shearwater platform and Hans Deul drilling rig because of the drifting gas.
The oil giant said the move was a “precautionary measure” because of drifting gas.
Exclusion zones have been put in place around the Elgin platform, which is operated by Total.
Coastguards said shipping was being ordered to to keep at least two miles away while there was a three-mile exclusion zone for aircraft.
All 238 workers were removed from the Elgin installation by helicopter on Sunday after the leaking gas was discovered.
Total said it was trying to bring the leak under control but has not yet been able to identify the source.
Union official Jake Molloy told BBC Scotland a gas cloud had now encircled the platform.
‘No fly zone’
A sheen of between two and 23 tonnes of gas condensate, and measuring six nautical miles in length, has been reported on the water nearby, and Total has activated its Oil Pollution Emergency Plan.
Shell confirmed on Monday evening it was flying non-essential personnel back to Aberdeen from its Shearwater platform and the nearby Hans Deul drilling rig.
The Shearwater and Elgin installations are about four miles apart.
Mr Molloy, regional organiser of the RMT union, said the gas cloud could be seen by people seven miles away.
He told BBC Radio Scotland he was not certain how the incident could be tackled.
He said: “As far as we can tell, certainly in the UK sector, this is an unknown. It has never occurred before.
“One drilling engineer that I have spoken to today says we could be looking at a Deepwater-type intervention, in that we have to drill a relief well from another rig, but even that will be dodgy if we have got gas continually escaping in the immediate region.
“As I understand it we have now got a no-fly zone and an exclusion zone of two miles around the installation.”
Total said efforts were continuing to try to bring the leak under control.
David Hainsworth, health, safety and environment manager for Total E&P UK, said it was coming from a well which may be connected to a non-productive reservoir.
He said it could potentially be difficult to bring under control
He added: “The release is continual at the moment. We have to evaluate the options available.
“We are mobilising experts from our headquarters in France and also consultants for well control.
“We will look at the options over the next day or two and see where we go. But it could continue for a prolonged period of time.”
The UK Department of Energy and Climate Change (DECC) has been monitoring the situation and said there was no indication of a risk of significant pollution to the environment.
In a statement the DECC said: “The priority now is to plan an appropriate response to contain the leak and minimise the impact to the environment.
“Total have established their Emergency Response Centre (ERC) and have activated their Oil Pollution Emergency Plan.
“A DECC Offshore Environmental Inspector has been present in the ERC and DECC continues to monitoring the ongoing response.”
The evacuation of the Elgin platform and nearby Rowan Viking drilling rig began at 12:15 on Sunday soon after the leak was discovered, with 150 workers flown back to Aberdeen and 69 taken to neighbouring installations.
But 19 essential personnel, who initially remained aboard the Elgin platform, were also flown back to Aberdeen in the early hours of Monday morning, leaving it unstaffed and powered down.
Deepwater Horizon, in the Gulf of Mexico, went down in April 2010 after an explosion on the rig caused by a blowout, killing 11 crewmen and igniting a fireball visible from 35 miles (56 km) away.
It caused the largest offshore oil spill in US history.