By Sybille de La Hamaide and Oleg Vukmanovic
PARIS/LONDON (Reuters) - French oil major Total dismissed fears on Wednesday of a blast at its Elgin North Sea platform, even though explosive natural gas is bubbling up less than 100 metres from a flare left burning when workers had to evacuate the site.
Despite the company's assurances, Total shares came under pressure from speculators, although some analysts said the gas leak off the Scottish coast did not yet appear to be as serious as the oil leak that caused BP's Deepwater Horizon disaster in 2010, the world's worst marine oil spill.
However, one energy industry consultant said the platform could become "an explosion waiting to happen" if the gas continued to pour from the leak for some time.
Total said on Wednesday that the flare, which normally burns to regulate gas pressure at safe levels, had not been shut down when the platform was evacuated on Sunday.
A Total UK spokesman in Aberdeen said the flare was on a separate platform from the leak, albeit only a short distance away.
"The flare is still burning but is not posing a risk. The leak is on the wellhead platform and the flare is on the Processing, Utilities and Quarters platform. There is a gap of 90 metres (300 feet) between the two," he said.
A spokesman for Total in Paris said a solution to block the leak was still being evaluated and it was a "a question of days". "We have not precisely identified the cause of the incident."
The firm warned on Tuesday it could take six months to halt the flow of gas, and analysts' opinions were divided on how serious the leak might be.
Industry consultant John Shanks said the stakes were potentially high and the offshore industry was closely following developments.
"The news this morning that the flare is still burning on the platform is thus unwelcome," said Shanks, who works at RiserTec, a specialist engineering consultancy based in the Scottish city of Aberdeen.
"Under normal conditions, the deeper the leak, the more difficult remedial work will be. However, if gas continues to leak at a steady or increased rate over a sustained period of time, the platform could become an explosion waiting to happen."
Credit ratings agency Fitch said current reports of the three-day leak suggest this unfolding incident was not as serious as the explosion at the Deepwater Horizon platform which resulted in oil pouring into the Gulf of Mexico.
"The Elgin leak is a surface gas leak rather than an underwater oil leak, making its potential for environmental damage far lower than in the Deepwater Horizon case," Fitch said in a statement.
Fitch said accidents like this are unpredictable and difficult to resolve but added it considered the potential was low for this leak to escalate to a crisis on the scale of Deepwater Horizon.
Simon Boxall, a marine expert and oceanographer at the National Oceanography Centre, Southampton, said that what seemed like a very serious incident 24 hours ago now appeared to be settling down, but risks remained.
"There is still a risk and they do need to stop the leak, because a chronic leak would build up hydrogen sulphide in the water. It's a problem that needs solving and it's not doing the environment any good, but it's not a major incident at this stage," he said.
Total said a preliminary assessment suggested there has been no significant impact on the environment.
The loss of oil and gas output from Elgin - as well as the prospect of a big repair bill - helped drive Total's share price down six percent on the Paris bourse on Tuesday and another 1.5 percent by 1100 GMT on Wednesday.
Speculators sold Total shares short - borrowing stock and selling it, in the hope that they could buy the shares back more cheaply later. The stock was among the most shorted stocks across Europe, according to Data Explorers.
"People still have in mind the BP saga. We don't know how this one will turn out, so it's better to get out of this stock now, or go 'short' if you're adventurous," a Paris-based trader told Reuters.
The explosion at the Deepwater Horizon rig killed 11 workers and ruptured BP's Macondo well, unleashing millions of barrels of oil into the Gulf of Mexico. BP struck a deal estimated at $7.8 billion with businesses and individuals suing over the spill.
The Elgin well, which pumps about three percent of Britain's gas output from six km (nearly four miles) below the seabed, pushes the frontiers of technology.
It is one of the deepest, most highly pressurized, offshore natural gas fields in the world and it now sits empty following Sunday's emergency evacuation of 238 crew.
(Additional reporting by Valerie Parent and Blaise Robinson in Paris, Henning Gloystein and Kate Kelland in London; writing by Geert De Clercq; editing by David Stamp and Philippa Fletcher)