London ( CNN ) -- Energy giant Total has found the source of a gas leak on an offshore oil platform in the North Sea , the company told CNN on Thursday . The leak is on the deck level of the well head platform , Total said . The Elgin platform sprang a leak Sunday , forcing the evacuation of the rig . Experts are working to decide whether they can wait for the gas to stop leaking on its own , or whether the company must drill a relief well or fill it with mud in a `` kill operation , '' Total said . Nearly 240 workers were taken off the rig as the problem developed Sunday , Total has said . The leak seems to have started as workers were sealing the well in the North Sea , about 150 miles ( 240 kilometers ) east of the Scottish city of Aberdeen . `` Ironically , it sounds as if , just like with the Deepwater Horizon , they were closing off a well and somewhere along the line something went wrong , '' oceanographer Simon Boxall said , referring to the major BP oil spill in the Gulf of Mexico in 2010 . The Elgin leak has echoes of the BP spill , but there are differences . The Elgin is in shallower water , which could make problems easier to fix , but it is leaking gas , rather than oil . Gas ignites more easily . `` This is nothing on the scale of the Gulf spill two years ago , '' Boxall said . `` This is a relatively light spill . The gas itself is dispersing quite rapidly . '' `` The hope is that there is so little gas pressure in there that it will just blow itself out , '' he said of the Elgin spill . Total 's share price was down about 2 % in trading in France on Thursday afternoon . The French company 's share price fell 7 % Tuesday on news of the leak , but market analyst firm Jeffries International said Wednesday that it thought the market had overreacted . A union representing workers on the rig warned Wednesday that there was an `` urgent need '' to stop the leak . `` If the gas cloud somehow finds an ignition source , we could be looking at complete destruction , '' said Jake Molloy , an official with the National Union of Rail , Maritime and Transport Workers . `` This is an unprecedented situation , and we really are in the realms of the unknown , '' he said . But oceanographer Boxall said the risk of explosion may not be as high as initially feared . `` Initially , the risk of explosion was seen as being very high . There were reports coming through of a large gas cloud enveloping the whole rig , '' he told CNN . But the fact that there has been no blast when the flare on the gas rig is still burning `` obviously contradicts the idea that there was a very high risk of explosion , '' he said . `` Perhaps the quantity of gas is not that great as first thought , '' he said . For the moment , the wind seems to be blowing the gas cloud away from the flare on the Elgin rig . The winds over the North Sea around the Eglin platform are predicted to remain strong ( 40-50 kph , with gusts over 60 kph ) and out of the northwest through Friday . On Saturday , the winds are expected to shift slightly out of the north , as an area of high pressure drifts eastward over the British Isles , and they should weaken Sunday . Scattered light showers are possible Friday and Saturday , but the area should stay mostly dry through the weekend . Total said there was a `` sheen on the water in the vicinity of the platform , '' but said Tuesday there was no indication of environmental damage and there had been no injuries . Shell partially evacuated two of its nearby platforms , Shearwater and Hans Deul , as a `` purely precautionary '' measure , it said Wednesday . The North Sea was the scene of the world 's worst offshore rig disaster , the Piper Alpha explosion , which killed 167 people in 1988 . CNN 's Bharati Naik and Brandon Miller contributed to this report .
The Elgin platform leak is not underwater , energy firm Total says . Total evacuated the rig in the North Sea after the leak Sunday . Experts are deciding whether leak will stop on its own , or if action is needed . Initial fears of an explosion may be unfounded , an oceanographer says .