Gas threat warning for oil-spill Gulf

It contains about 40 per cent methane, compared with about five per cent in typical oil deposits, said US oceanographer John Kessler.

That means huge quantities of methane have entered the Gulf, scientists say, potentially suffocating marine life and creating "dead zones" where oxygen is so depleted that nothing lives.

"This is the most vigorous methane eruption in modern human history," Professor Kessler said.

Methane is a colourless, odourless and flammable substance that is a major component in natural gas. Petroleum engineers typically burn off excess gas attached to crude before the oil is sent to the refinery. BP has done that as it captured more than 7.5 million gallons of crude from the breached well.

A BP spokesman said the company was burning about 30 million cubic feet of natural gas daily from the source of the leak, adding up to about 450 million cubic feet since the containment effort started 15 days ago, enough gas to heat about 450,000 homes for four days.

But that figure does not account for gas that eluded containment efforts and ended up in the water, leaving behind huge amounts of methane.

Scientists are still trying to measure how much methane has escaped into the water and how it may damage the Gulf and its creatures.

The small microbes that live in the sea have been feeding on the oil and natural gas in the water and are consuming larger quantities of oxygen, which they need to digest food. As they draw more oxygen from the water, it creates two problems. When oxygen levels drop low enough, the breakdown of oil grinds to a halt; and as it is depleted in the water, most life cannot be sustained.

The National Science Foundation funded research on methane in the Gulf amid concerns about the depths of the oil plume and questions what role natural gas was playing in keeping the oil below the surface.

Meanwhile, BP chief executive Tony Hayward, who faced a relentless slating at the hands of US politicians during a confrontation over the Gulf spill, has received a vote of confidence at home, by getting Alan Sugar's backing.

The Enterprise Tsar said Mr Hayward said the businessman should "definitely not" be fired, stating: "I feel pretty sorry for him at the moment under the pressure he is experiencing."

Mr Hayward's appearance on Capitol Hill on Thursday came less than 24 hours after BP announced it was to set up a 13bn compensation fund and scrap shareholder dividends until the end of the year.