This was just put out by Reps. Boehner (Ohio), Cantor (Va.) and Pence (Ind.):

“The oil spill in the Gulf is this nation’s largest natural disaster and stopping the leak and cleaning up the region is our top priority. 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. “The families and businesspeople in the Gulf region want leadership, accountability and action from BP and the Administration. It is unacceptable that, 59 days after this crisis began, no solution is forthcoming. Simply put, the American people want all of our resources, time and focus to be directed toward stopping the spill and cleaning up the mess.” And Barton follows up with a more formal, full-monty statement. He “retract[s]” his apology to BP:

“I apologize for using the term ‘shakedown’ with regard to yesterday’s actions at the White House in my opening statement this morning, and I retract my apology to BP. As I told my colleagues yesterday and said again this morning, BP should bear the full financial responsibility for the accident on their lease in the Gulf of Mexico. BP should fully compensate those families and businesses that have been hurt by this accident. BP and the federal government need to stop the leak, clean up the damage, and take whatever steps necessary to prevent a similar accident in the future.
“I regret the impact that my statement this morning implied that BP should not pay for the consequences of their decisions and actions in this incident.”

UPDATE: The word is that the GOP reacted swiftly to the Barton comments, giving him an ultimatum. And even after his apology, it looks like his position is anything but assured:

House Republican leaders told Rep. Joe Barton that he would be stripped of his ranking member status on a key committee Thursday if he did not immediately apologize for comments earlier in the day accusing President Obama of a “shakedown” of oil giant BP, sources told the Daily Caller.
“He was told, ‘Apologize, immediately. Or you will lose your position, immediately,” a House GOP leadership aide said, describing a meeting between Barton and House Minority Leader John Boehner and House Minority Whip Eric Cantor.
“Now that he has apologized, we’ll see what happens going forward,” the GOP aide said.