BP has been accused of "unacceptable" neglect of pipelines in Alaska, after an oil spill forced the partial closure of the largest oil field in the US.
BP bosses faced a barrage of criticism from legislators
At a Congressional hearing, lawmakers chided the firm for policies which they said were as "rusty as its pipelines".
BP was forced to close part of the Prudhoe Bay oil field after discovering serious corrosion in many pipelines.
Under questioning, BP bosses admitted some failures but said Prudhoe could resume full production next month.
Robert Malone, one of two BP executives testifying, said the firm had "fallen short of the high standards we hold for ourselves".
BP has been under growing scrutiny in the US following a number of damaging incidents over the past 18 months.
An explosion and subsequent fire at its Texas City refinery near Houston last year killed 15 people.
Last month it was forced to stop production from about half of the Prudhoe site, which accounts for about 8% of US oil output.
A serious spill at the same site in March saw 200,000 gallons of oil leak.
A criminal investigation is underway into the current shutdown while the oil giant is being sued by one shareholder group.
Representatives from both parties lined up to criticise BP during the hearing, arguing that its reputation for probity and progressive environmental policies had been weakened by recent events.
"Years of neglecting to inspect two of the most vital oil pipelines in this country is simply unacceptable," said Joe Barton, the Republican chairman of the House energy and commerce committee.
BP's operational problems have come at a time when it is making record profits, in part due to oil prices remaining near historic highs.
"BP stands for a company with bloated profits that failed to fix broken pipelines," said Ed Markey, a Democratic member from Massachusetts.
Mr Malone, BP's most senior US executive, said the firm had "stumbled operationally" in recent times but pledged to work with Congress and regulators to restore public confidence in the firm.
Richard Woollam, former head of corrosion management at Prudhoe Bay, asserted his right under the Fifth Amendment not to testify so as to refrain from potentially incriminating himself.
BP recently placed Mr Woollam, who was moved from his post last year, on "administrative leave".
"We encouraged Mr Woollam to co-operate with the committee and are disappointed by his decision," a BP spokesman said.
BP has pledged to spend $550m on maintaining pipelines in Alaska
US Energy Secretary Sam Bodman, also giving evidence at the hearing, said he believed BP had been guilty of "management failures".
But he said the firm had responded quickly to criticism of its maintenance record at Prudhoe and could still bid for other major energy projects in the US.
BP has launched an independent review of corrosion inspection and monitoring of all its pipelines at Prudhoe and across Alaska.
BP is to spend $550m maintaining its pipeline network in Alaska, including the replacement of 16 miles of oil transit pipelines.
Separately, BP has launched an independent investigation into allegations of bullying and worker intimidation at its operations on the North Slope of Alaska since 2000.
"These concerns will be reviewed to determine if the problems have been addressed and rectified," Mr Malone said.