Reporting from Louisiana and Los Angeles — — As BP continued its effort to gain control of its untamed deep-sea well, President Obama announced more restrictions on offshore oil drilling Thursday and insisted his administration is firmly in charge of the response to the spill, now believed to be the largest in U.S. history.
Batting away suggestions that the federal response has been lackluster and that BP executives have been calling some of the shots, Obama insisted that "BP is operating at our direction."
"Every key decision and action they take must be approved by us in advance," Obama said. If the Coast Guard orders BP to do something, he added, "they are legally bound to do it."
More than 24 hours after BP began a crucial "top kill" effort to plug the deep-sea well with heavy drilling mud, company executives said the procedure was going as planned but they were not ready to declare success.
Although incident commander Adm. Thad Allen of the U.S. Coast Guard said Thursday morning that BP had temporarily stopped the flow of oil, the company's chief operating officer later said petroleum was still flowing. "Once the well has stopped flowing then we would pump cement down into the hole to fully seal it," Doug Suttles said. "We might finish this in the next 24 hours, or it might take longer." Engineers next plan to inject heavier "bridging material" above the mud to prepare to put a cement seal on the well.
The developments came on a day when a new spill estimate indicates that the BP leak is more than twice the size of the 1989 Exxon Valdez spill, making it the worst oil disaster in U.S. history.
As much as 29 million gallons of crude have poured into the gulf by those estimates, creating a toxic legacy that will linger for months and possibly years in waters that lap thousands of miles of shoreline and harbor some of the nation's richest fisheries.
The head of the scandal-plagued federal agency that oversees oil and gas drilling resigned, and in Louisiana, testimonies from survivors of the April 20 Deepwater Horizon explosion raised new questions about how crew members responded in the chaotic early minutes of the disaster.
The spill prompted the president to hold his first full-fledged news conference in months and to plan a Friday trip to the Gulf Coast to review the damage, his second to the region since the rig explosion, which killed 11 people.
In a White House news briefing, Obama called the five-week-old BP spill an "economic and environmental tragedy" and said he was frustrated and angry over its duration. Every morning when he's finished shaving, he said, one of his daughters quizzes him: "Did you plug the hole yet, Daddy?"
Obama announced drilling restrictions that Interior Secretary Ken Salazar later said amounted to hitting "the pause button on deep-water exploration."
Salazar on Thursday ordered a sweeping moratorium on offshore lease sales and directed that all 33 exploratory rigs operating in deep water in the Gulf of Mexico be shut down as soon as possible.
The directive does not affect 591 deep-water and 4,515 shallow-water wells that are already producing oil or gas.
Salazar also put a hold, until 2011, on controversial drilling plans for the Chukchi and Beaufort seas in the Alaskan Arctic, where environmentalists fear a spill could be more disastrous than the gulf leak. Two additional lease sales will be canceled: one scheduled for August in the gulf and a 2012 lease sale off Virginia.
Obama blamed practices of the previous administration for poor regulation, citing a "cozy and sometimes corrupt relationship" between oil companies and federal regulators. He described as "appalling" the findings of a recently released Interior inspector general's report that detailed ethical lapses in a Louisiana office of the Minerals Management Service, which oversees oil and gas operations.
Salazar has instituted changes since he became secretary, Obama said, but the "culture had not fully changed" within the agency at the time of the spill. "Absolutely, I take responsibility for that," Obama said.
Thursday the director of Minerals Management Service, S. Elizabeth Birnbaum, resigned in a two-paragraph letter to Salazar. In a statement, Salazar called her "a strong and effective person and leader" and said she resigned "on her own terms and on her own volition."
"She helped …us take important steps to fix a broken system," he added. "She is a good public servant."
As Capitol Hill lawmakers stepped up criticism of BP, workers testifying before an investigatory committee near New Orleans on Thursday raised questions about whether enough actions were taken to prevent the accident from reaching a crisis point.