BP was told of oil safety fault 'weeks before blast'

A Deepwater Horizon rig worker has told the BBC that he identified a leak in the oil rig's safety equipment weeks before the explosion.

Tyrone Benton said the leak was not fixed at the time, but that instead the faulty device was shut down and a second one relied on.

BP said rig owners Transocean were responsible for the operation and maintenance of that piece of equipment.

Transocean said it tested the device successfully before the accident.

Meanwhile, BP has said that its costs in tackling the disaster have now risen to $2bn (£1.34bn).

'Unacceptable'

On 20 April, when the Deepwater Horizon rig exploded killing 11 people, the blowout preventer, as the device is known, failed.

Blowout preventer

Investigations into the US oil spill are focused on the blowout preventer system of valves on the seabed.

The system's control panel is its electronic "brains", keeping valves open to allow flow from well to rig.

In an emergency, hydraulic valves or shear rams should close shut on the pipe, sealing it and preventing flow.

BACK 1 of 3 NEXT

The most critical piece of safety equipment on the rig, they are designed to avert disasters just like the oil spill in the Gulf of Mexico.

The blowout preventer (BOP) has giant shears which are designed to cut and seal off the well's main pipe. The control pods are effectively the brains of the blowout preventer and contain both electronics and hydraulics. This is where Mr Benton said the problem was found.

"We saw a leak on the pod, so by seeing the leak we informed the company men," Mr Benton said of the earlier problem he had identified. "They have a control room where they could turn off that pod and turn on the other one, so that they don't have to stop production."

Professor Tad Patzek, petroleum expert at the University of Texas, was blunt in his assessment: "That is unacceptable. If you see any evidence of the blowout preventer not functioning properly, you should fix it by whatever means possible."

Mr Benton said his supervisor e-mailed both BP and Transocean about the leaks when they were discovered.