U.S. lawmakers investigating the massive oil leak in the Gulf of Mexico say there were problems with one of the well's key safety systems.
The chairman of the House of Representatives Committee on Energy and Commerce, Henry Waxman, said during a hearing Wednesday that the oil rig's so-called fail-safe system was leaking fluid in the hours before the rig exploded on April 20.
Waxman, a Democrat, also said that another part of the safety system had a defective part.
Democrat Ed Markey criticized the response by BP and the other companies involved, saying they were "making it up as they go."
Representatives from the companies involved with the oil rig - BP, Transocean, Halliburton and Cameron - testified Wednesday before a House committee. Tuesday, before a Senate panel, executives from BP, Transocean and Halliburton blamed each other for the disaster.
At the hearing Wednesday, Representative Markey accused the companies involved with the rig of conducting what he called a risky science experiment at the bottom of the gulf.
The oil rig off the coast of Louisiana sank April 22. Eleven workers were killed in the accident. BP has been trying to fix the leak, which officials estimate is spewing some 795,000 liters of oil each day.
The spill is threatening economic and ecological damage to the U.S. Gulf Coast region. The White House said Wednesday it will introduce legislation that would allow the government to collect more money from companies responsible for oil spills.
BP has lowered a second containment box in the gulf in an attempt to stop the leak. The structure is a smaller version of a four-story-tall containment dome that was unsuccessfully deployed last week to capture some of the oil leaking from the ruptured well.
BP officials say the box will not be placed over the well until at least Thursday because they want to make sure the box is configured correctly.
The spill has so far cost BP about $350 million. The amount includes $3.5 million to pay 295 of 4,700 claims it has received for economic damages.
Some information for this report was provided by Reuters.
