A BLOWOUT preventer which failed to stop oil from spewing into the Gulf of Mexico has been removed from BP’s well.
A spokesman said the 50ft, 300-tonne device was detached from the wellhead yesterday afternoon.
The device is slowly being lifted to the surface and is unlikely to reach the top until later today.
Earlier, a vessel latched on to the preventer to raise it from a mile beneath the sea.
It is considered a key piece of evidence. Investigators hope to find out why it failed to prevent the spill.
The April 20 explosion on board the Deepwater Horizon killed 11 workers and led to 206million gallons of oil spewing from BP’s undersea well.
Investigators know the explosion was triggered by a bubble of methane gas which escaped from the well and shot up the drill column, expanding quickly as it burst through several seals and barriers before igniting.
But they do not know how or why the gas escaped. And they do not know why the blowout preventer did not seal the well pipe at the sea bottom after the eruption, as it was supposed to.
Future liabilities faced by a number of corporations could ride on their analysis.
The ruptured well has been shut since July 15 and work to replace the rig’s blowout preventer began this week.
The relief well that will seal the well permanently is expected to be completed by the middle of the month.
Earlier yesterday, BP said the cost of tackling the disaster had risen to about £5.2billion.
The company has paid out about £278million in claims so far.
Provisions for the crisis sent BP crashing £11billion into the red for the April-June period — its first loss in 18 years.
BP said more than 28,400 staff were working on the relief efforts, as well as 4,050 vessels and dozens of aircraft. At the peak of the crisis, 3.5million feet of containment boom was used to rein in the spill, although this has now been reduced to 1.72million.
The company has come under heavy fire in the US but the political pressure has eased since it set up a £13billion fund to meet compensation payouts and costs.
It hopes to sell about 10% of its production assets over the next 18 months, with the aim of raising £20billion to beef up its balance sheet in the wake of the crisis.