BP engineers lowered a cap over the top of the company's blown-out well Thursday night, an important step in efforts to contain the thousands of barrels of oil spewing daily into the Gulf of Mexico.
"The placement of the containment cap is another positive development in BP's most recent attempt to contain the leak; however, it will be some time before we can confirm that this method will work and to what extent it will mitigate the release of oil into the environment," Coast Guard Adm. Thad Allen, the national incident commander for the spill, said in a written statement.
"Even if successful, this is only a temporary and partial fix, and we must continue our aggressive response operations at the source, on the surface and along the gulf's precious coastline," he said.
Live video streams showed oil still billowing around the cap, as engineers worked to make sure it was correctly aligned.
BP next planned to attempt to pump oil and gas from the well up through a pipe to a ship a mile above. The pumping was likely to last several hours before the oil and gas reached the ship, at which point, if all went as planned, the oil plume around the leak was expected to diminish.
President Obama planned to review the effort during a return trip to the gulf region Friday. .
The visit would be Obama's third since the April 20 explosion on the Deepwater Horizon killed 11 people and unleashed what has become the largest oil spill in U.S. history. The administration, which in the last week has assumed a more demanding stance toward BP, on Thursday sent the company a preliminary cleanup bill for $69 million, a small portion of the estimated $1-billion cost of the spill response so far.
The containment operation had moved ahead after undersea robots succeeded in shearing a leaking riser pipe connected to the blown-out wellhead.
"We recognize this is just the beginning," BP Chief Executive Tony Hayward said as the capping operation got underway earlier Thursday. He promised that his company would work as long as it takes to clean up the spill and restore the livelihood and way of life to gulf residents.
Unable to make a finely calibrated cut when an industrial-sized, diamond-wire saw became stuck, engineers used giant hydraulic shears to cleave the pipe, leaving a rougher edge that will be more difficult to seal and potentially allow more oil to escape.
"This is an irregular cut. It will be a bit more challenging," Adm. Allen said at a briefing Thursday morning.
Since last week's futile attempt to plug the deep-sea well with a long-planned "top kill" procedure, federal officials have emphasized that the final fix is still a couple of months away. It will be August before either of two relief wells are completed and ready to pump cement into the bottom of the damaged well, permanently sealing it. And experts have cautioned that the tricky maneuver may not succeed on the first try.
Drilling of the relief wells could also be hampered by the arrival of hurricane season, which began Tuesday and could send fierce storms howling across the spill site.
BP also launched a national ad campaign Thursday, apologizing for the spill and assuring the public that it would pay for the cleanup and all legitimate economic damages. "The gulf spill is a tragedy that never should have happened," Hayward said in a TV spot that began airing.
Hayward's appeal contrasted with the flippant tone of a remark he made to reporters Sunday, saying that he "would like his life back." Fishermen and other Gulf Coast residents expressed outrage at the comment. In a mea culpa posted on BP's Facebook page Wednesday, Hayward acknowledged that he "made a hurtful and thoughtless comment."
"When I read that recently, I was appalled," he said. "I apologize, especially to the families of the 11 men who lost their lives in this tragic accident."
BP may have a long way to go in varnishing its image. Protest groups have planned a week of anti-BP demonstrations in 50 cities. Thursday, the credit rating firms Moody's Investors Service and Fitch Ratings lowered their assessments of BP's long-term debt.
Fitch cut BP's debt rating to AA from AA+, citing the potential for civil and criminal charges, as well as increasing "risks to both BP's business and financial profile." Fitch estimated that the company could spend as much as $3 billion on cleanup this year.
The portion of federal gulf waters closed to fishing is now approaching 40% as strands of the slick move toward Florida. There were reports of oily substances and tar balls reaching the Florida Keys. Scientists predicted Thursday that oil from the massive spill is all but certain to circle Florida and travel up the Atlantic Coast as early as this summer.