With five times more oil leaking into the Gulf of Mexico than originally estimated and the price tag for last week's explosion predicted at $8 billion, questions about BP's response and level of responsibility are mounting.
Doug Suttles, the energy company's chief operating officer, admitted some responsibility for the disaster "because we're the lease holder," but assigning blame, he said, should come after the cleanup.
"I can tell you we're not worried about that right now," he said. "Who's ultimately responsible for what will come out over time through an investigations process."
The new leak estimate is about 5,000 barrels a day, according to the National Oceanic and Atmospheric Administration. Suttles told "Good Morning America" he still believes it to be between 1,000 barrels -- the company's original estimate -- and 5,000.
The Deepwater Horizon rig was reportedly not equipped with a shutoff switch that could have been used to try to close the well. Such switches are not required in the United States, but are used in other countries such as Norway and Brazil.
But Suttles said the rig was equipped with some safety devices that should have prevented this kind of spill.
"They didn't do that, we don't know why they didn't do that and ultimately we will find out," he said.
Suttles was quick to point out that another company was operating the rig at the time of the explosion, not London-based BP.
"I can say that we had equipment required by the regulations," he said. "We don't know why, when the accident occurred, and I should probably clarify, the lease we are drilling on is owed by BP and a few other companies."
Parts of the massive spill were lit on fire Wednesday as part of a controlled yet risky burn as a last resort to try and stop the oil slick from reaching the coastline.
"It's not a perfect solution," said Jackie Savitz Sr., campaign director for the Oceana Pollution Program. "It does increase air pollution and it can cause inhalation problems for marine life."
Officials may try another burn but it appears the oil will reach the coastline, threatening as many as 400 species, including sea turtles and dolphins. The Gulf's abundant oyster and shrimping grounds could also be affected.
Suttles said BP is actively working with the Gulf states to minimize the impact.
Some floating oil has come within 20 miles of shore. Adm. Thad W. Allen, commandant of the U.S. Coast Guard, told reporters in Miami today that depending on winds and weather, crews might have two to three days before oil hits land.
Gulf of Mexico Oil Spill: Burn Less Risky Than Alternatives
The Deepwater Horizon drilling rig, operated by BP Oil and owned by Transocean Ltd., exploded and started burning April 20. Eleven rig workers were never found and are presumed to have died.
Engineers said Wednesday's burn was less risky than the alternatives.
"When you've got an oil leak like this, you use every tool in the toolbox to keep it offshore," said Edward Overton, a professor emeritus of environmental sciences at Louisiana State University in Baton Rouge. "If it gets to shore, it's going to coat everything with this sticky, gooey stuff and create a tremendous, awful mess."
The Coast Guard said oil continues to spew from the wellhead, 5,000 feet beneath the surface of the gulf, at a rate of about 42,000 gallons per day. Satellite images show the resulting slick drifting north and eastward toward the coasts of Louisiana, Mississippi, Alabama and Florida.
"It's premature to say it's catastrophic," said Coast Guard Rear Admiral Mary Landry, who is leading the operation. "I will say it's very serious."
BP and its contractors are fighting a high-stakes battle to keep the spill from getting worse. They have tried, unsuccessfully so far, to cover the leaking wellhead with a dome or close it with a submersible robot. The company has said it is spending $6 million per day in the effort -- and the problem continues to grow.
Oil from the area is called sweet crude, but LSU's Overton said the name is deceptive. It contains heavy compounds, called asphaltenes, that do not burn easily or evaporate, even in the warm climate off Louisiana.
"When you've got a spill like this," said Overton, "there are three things you can do. You can burn it, scoop it up out of the water, or use chemical dispersants to break it up. This oil is not particularly good with any of those three."
"With light crude," he said, "you could burn most of it -- 70 or 80 percent. With heavy crude, I don't know. I'm not optimistic."
ABC News Radio and The Associated Press contributed to this report.