A key safety device known as a blowout preventer used in the BP oil rig in the Gulf had a hydraulic leak and other problems that likely prevented it from working as designed -- a malfunction that BP may have known about before the April 20 explosion, congressional investigators said Wednesday.
They also said documents from BP PLC and others also indicated confusion over whether poor pipe integrity was allowing methane gas to leak into the well just hours before the explosion that killed 11 workers and blew the well open.
Rep. Henry Waxman, a California Democrat, said that BP had informed his House committee that at some point when the well was being closed with cement, an influx of methane entered the wellhead, indicating that cementing the well had not produced needed pipe integrity.
Waxman, opening a hearing into the April 20 well explosion that unleashed a massive oil spill, said while "we have far more questions than answers" it appeared clear -- from BP and other documents -- that there were problems with the blowout preventers before the accident and confusion almost right up to the time of the explosion over the success of the cementing process.
The committee said that there were at least "four significant problems with the blowout preventer" used on the Deepwater Horizon drill rig.
Rep. Bart Stupak, a Michigan Democrat, said that a 2001 report by Transocean, which made the device, indicated there can be as many as 260 failure possibilities in the equipment. The device is supposed to be the final safeguard against a well blowout by clamping down and sealing a gushing oil well.
"How can a device that has 260 failure modes be considered fail-safe?" asked Stupak.
The House Energy and Commerce Committee was to hear from executives of BP, Transocean Ltd, Halliburton, which conducted the cementing on the BP rig, and Cameron Inc.
Stupak said BP confirmed in documents that a leak had been found in the hydraulic system that provides emergency power to a part of the blowout preventer.
When a remote underwater vehicle tried to activate the safety device, a loss of hydraulic pressure was detected, said Stupak.
In the Gulf, crews lowered a new containment box to the seafloor in preparation for the latest bid to funnel the gusher to a waiting tanker.
The blown well has spewed at least 4 million gallons (15 million liters) of oil into the Gulf over three weeks.
"If this is like other catastrophic failures of technological systems in modern history, whether it was the sinking of the Titanic, Three Mile Island, or the loss of the Challenger, we will likely discover that there was a cascade of failures and technical and human and regulatory errors," said Sen. Jeff Bingaman, chairman of the Energy and Natural Resources Committee.
BP's latest bid to stop the oil leak was a new containment box that reached the seafloor overnight after being lowered late Tuesday by a crane from the deck of the Viking Poseidon. The box, dubbed a top hat, was initially set down away from the gusher while engineers work to avoid problems that scuttled an earlier effort, BP spokesman Bill Salvin said.
The first box sent down last week weighed 100 tons and company officials had hoped it could contain 85 percent of the oil. However, it was never tried at such depths -- about a mile (1.6 kilometers) below the surface. A slushy mixture of gas and water clogged the opening in the top of the peaked box and it was cast aside.
The latest box is much smaller -- just 2 tons. It won't be placed over the spewing well right away because engineers want to make sure everything is configured correctly and avoid the same buildup, Salvin said. Crews also planned to pump in heated water and methanol so ice won't amass.
Coast Guard Petty Officer Connie Terrell said it is about 35 degrees (1.7 Celsius) Fahrenheit at the bottom of the sea floor where the oil is spilling.
And, in yet another sign the spill is getting worse, Louisiana wildlife officials said Wednesday that tar balls had washed ashore in South Pass in the state's southeastern tip. The marshy area is home to prime waters for shrimp and other seafood.