Total claims it is doing all it can to locate the source of a leak at the Elgin platform (Reuters / Charles Platiau)

An exclusion zone has been set up around a leaking North Sea gas rig over fears that it could trigger an explosion.

The Elgin platform, 140 miles East of Aberdeen, began leaking on Sunday as workers attempted to plug the well, which was no longer in production.

The leak has surrounded the platform with a methane gas cloud, while a sheen of oil condensates is thought to cover the surface of the water for nearly five square miles.

A two-mile exclusion zone for shipping and a three-mile exclusion zone for aircraft has been set up as oil engineers attempt to ascertain the location of the leaks.

It is thought that it could take as long as six months for the engineers to drill a relief well to the leaking gas field.

Total could then close off the leaking wellhead with a concrete plug, an action that was taken during the Deepwater Horizon spill in the GUlf of Mexico in 2010.

Fears continue to grow that any naked flame within the flammable gas cloud could lead to a huge explosion, although Total claimed that the situation was "stable" in a statement.

Total claimed it was continuing to take "all possible measures" to identify the source of the leak, which could be one of several points above the reservoir at the base of the drill shaft.

Total's manager for health, safety and environment, David Hainsworth, said: "The gas is flammable but the platform power was turned off to minimise risk of ignition, but clearly there's a risk.

"We have taken away a series of risks but there is always a possibility; it's low but you never say never. The best-case scenario is that the gas in this area is not very productive abd it dies off in the coming days and weeks/

"At the moment there is no real evolution of the sheen on the sea, but if that was to change, then the exclusion zone may be increased."

Simon Boxall, of the National Oceanography Centre in Southampton, said the leak could kill thousands of animals and plant life, due to the release of hydrogen sulphide.
He told the Guardian: "This will make the water slightly more acidic, but the effect will be short-lived and localised, and therefore should not cause too much harm to marine life,"

All of the 219 workers were evacuated from the platform and the nearby Rowan Viking drilling rig.