BP knew of equipment problems onboard the Deepwater Horizon rig hours before the explosion pumped millions of gallons of oil into the Gulf of Mexico, a US congressional hearing has been told.
In the second day of hearings, the House of Representatives Energy and Commerce Committee said documents and testimonies suggest that BP, Transocean and Halliburton ignored tests that indicated faulty safety equipment.
The committee said testimonies from oil executives indicate multiple failures of safety systems that should have cut off the oil flow or at least given an advance warning of a blowout.
The safety failures include a dead battery in the blowout preventer, suggestions of a gap in the well casing, failure in the shear ram and a device that was supposed to cut through and plug the drill pipe if any explosion occurs.
Meanwhile, the White House has asked Congress to approve $118m in recovery costs, which will be passed onto BP.
The new regulatory crackdown on offshore oil drilling is expected to defer development of US deposits, which hold billions of barrels of crude.
US Interior Secretary Ken Salazar has suspended all new permits for offshore drilling until the inquiry into the blast and subsequent oil slick is finalised.