A US government panel is to question BP's US chief Lamar McKay over the Gulf oil disaster amid damning accusations the firm took shortcuts. McKay has been called to testify along with heads of other oil companies about the safety of deep-water drilling.
Documents released on Monday seemed to show that BP made a series of money-saving shortcuts and blunders that dramatically increased the danger of a destructive oil spill in a well that an engineer ominously described as a "nightmare" just six days before the blowout.
US Congressmen have suggested in a letter to BP that the company took decisions which raised the risk of a disaster.
President Barack Obama is due to make a speech to the nation on the spill. He is expected to outline the next steps his administration will take when he appears on prime-time TV this evening.
The president has been touring American Gulf states affected by the leak, which he has likened to the 9 / 11 attacks in terms of its impact.
Oil has been spewing into the Gulf of Mexico since a drilling rig leased by BP exploded and sank on 20 April with the loss of 11 lives. The US Coast Guard estimates that about 35,000 barrels still escape each day.