The Total oil company is facing a growing crisis in the North Sea after a leak at its Elgin platform forced wider evacuations off the Scottish coast Tuesday.

The leak, which was detected over the weekend at the site 150 miles east of Aberdeen, has been dubbed the well from hell by one environmentalist and has led to a cloud of explosive gas forming above the platform, forcing the evacuation of workers there, and then from nearby Shell installations.

The French oil major also announced Tuesday it may take up to six months to plug the leak if quicker, but riskier, alternatives prove unsuccessful.

According to the company's senior health and safety manager, David Hainsworth, there are two options to kill the well.

One is drilling a relief well, which could take about six months, he told Reuters.

A second, riskier alternative would be to send in engineers to kill the leak at its source.

This, he said would be a faster option.

Total officials are also hoping the well, which had been pumping 9 million cubic meters of gas per day or 3 percent of the UK's output, could die on its own.

This is the dream option, Hainsworth added.

Shares in Total fell 7 percent Tuesday to $51.25, as investors reacted to worsening news about the leak.

In a statement, British Energy Minister Charles Hendry said: The U.K. government is carefully monitoring the gas leak and believes the right measures are being taken.

Any leak we take very seriously and we think the right measures are being taken to address it and understand it.

Total has flown in a team of 10 to 20 specialists, and also is calling on the expertise of Wild Well Control, who were involved in killing BP's Deepwater Horizon oil spill in the Gulf of Mexico in 2010.

Environmental campaigners have been quick to criticize Total.

This is the well from hell, said the activist, Frederic Hauge, head of Bellona, a leading Norwegian group that closely monitors the oil industry.

This problem is out of control.