Channeling the nation's anger, lawmakers pilloried BP's boss in a withering day of judgment Thursday for the oil company at the center of the Gulf calamity. Unflinching, BP chief executive Tony Hayward said he was out of the loop on decisions at the well and coolly asserted, "I'm not stonewalling."

A protestor scuffles with a security person as British Petroleum (BP) Chief Executive Officer Tony Hayward testifies on the BP oil spill in the Gulf of Mexico before the House Energy and Commerce Committee on Capitol Hill in Washington D.C., the United States, June 17, 2010. [Zhang Jun/Xinhua]

That infuriated members of Congress even more, Democrats and Republicans alike.

Testifying as oil still surged into the Gulf of Mexico and coated ever more coastal land and marshes, Hayward declared "I am so devastated with this accident," "deeply sorry" and "so distraught."

Yet the oil man disclaimed knowledge of any of the myriad problems on and under the Deepwater Horizon rig before the deadly explosion, telling a congressional hearing he had only heard about the well earlier in April, the month of the accident, when the BP drilling team told him it had found oil.

"With respect, sir, we drill hundreds of wells a year around the world," Hayward told Republican Rep. Michael Burgess of Texas.

"Yes, I know," Burgess shot back. "That's what scaring me right now."

Phil Gingrey, R-Ga., told the CEO: "I think you're copping out. You're the captain of the ship." Democrats were similarly, if more predictably, livid.

"BP blew it," said Rep. Bart Stupak, D-Mich., chairman of the House investigations panel that held the hearing. "You cut corners to save money and time."

The verbal onslaught had been anticipated for days and unfolded at a nearly relentless pace.

But in a jarring departure that caught fellow Republicans by surprise, Rep. Joe Barton, top GOP member of the panel, used his opening statement to apologize -- twice -- for the pressure put on the company by President Barack Obama to contribute to a compensation fund for people in the afflicted Gulf of Mexico states.

Barton said the US has "a due process system" to assess such damages, and he decried the $20 billion fund that BP agreed to Wednesday at the White House as a "shakedown" and "slush fund." He told Hayward, "I'm not speaking for anybody else. But I apologize."

He later retracted his apologies to BP, then apologized anew -- this time for calling the fund a "shakedown." "BP should bear the full financial responsibility for the accident," he said, and "fully compensate those families and businesses that have been hurt by this accident."

Barton's earlier remarks were clearly an embarrassment for the party. House Republican leaders John Boehner, Eric Cantor and Mike Pence issued a statement asserting: "Congressman Barton's statements this morning were wrong. BP itself has acknowledged that responsibility for the economic damages lies with them and has offered an initial pledge of $20 billion dollars for that purpose."