VENICE, La. -- BP's chairman defended his company's safety record and said Sunday that "a failed piece of equipment" was to blame for a massive oil spill along the Gulf Coast, where President Barack Obama was headed for a firsthand update on the slick creeping toward American shores.
BP PLC chairman Lamar McKay told ABC's "This Week" that he can't say when the well a mile beneath the sea might be plugged. But he said he believes a 74-ton metal and concrete box - which a company spokesman said was 40 feet tall, 24 feet wide and 14 feet deep - could be placed over the well on the ocean floor in six to eight days.
McKay said BP officials are still working to activate a "blowout preventer" mechanism meant to seal off the geyser of oil.
"And as you can imagine, this is like doing open-heart surgery at 5,000 feet, with – in the dark, with robot-controlled submarines," McKay said.
Company spokesman Bill Salvin said Sunday that the first of three boxes is nearly done. It's being built in Port Fourchon, La., by a company called Wild Well Control.
Another spokesman, Steve Rinehart, said the oil will flow into the chamber and then be sucked through a tube into a tanker ship at the surface.
BP did not build the containment devices before the spill because it "seemed inconceivable" the blowout preventer would fail, Rinehart said.
"I don't think anybody foresaw the circumstance that we're faced with now," he said. "The blowout preventer was the main line of defense against this type of incident, and it failed."
Salvin said McKay was talking about the blowout preventer as the failed equipment that caused the April 20 explosion of the Deepwater Horizon rig, which killed 11 people. The blowout preventer typically activates after a blast or other event to cut off any oil that may spill.
The cause of the blast remains undetermined, and Salvin said "we're not ruling anything out." The rig was operated by BP PLC and owned by Transocean Ltd.
Crews have had little success stemming the flow from the ruptured well on the sea floor off Louisiana or removing oil from the surface by skimming it, burning it or dispersing it with chemicals. The churning slick of dense, rust-colored oil is now roughly the size of Puerto Rico.
Federal authorities banned commercial and recreational fishing in a large stretch of water off four states, from the mouth of the Mississippi River off Louisiana to western parts of the Florida Panhandle.
The National Oceanic and Atmospheric Administration said the closure would last for at least 10 days and was aimed at keeping seafood safe. Government scientists were taking samples from waters near the spill to determine whether there is any danger.
Long tendrils of oil sheen made their way into South Pass, a major channel through the salt marshes of Louisiana's southeastern bootheel that is a breeding ground for crab, oysters, shrimp, redfish and other seafood.
Venice charter boat captain Bob Kenney lamented that there was no boom in the water to corral the oil, and said BP was "pretty much over their head in the deep water."
"It's like a slow version of Katrina," he added. "My kids will be talking about the effect of this when they're my age."
There is growing criticism that the government and oil company BP PLC should have done more to stave off the disaster, which has cast a pall over the region's economy and fragile environment.
The White House dispatched two Cabinet members to make the rounds on the Sunday television talk shows. Homeland Security Secretary Janet Napolitano said on "Fox News Sunday" that the government has taken an "all hands on deck" approach to the spill since the BP oil well ruptured.
Interior Secretary Ken Salazar told NBC's "Meet the Press" that it could take three months before workers attain what he calls the "ultimate solution" to stopping the leak – drilling a relief well more than 3 miles below the ocean floor.
However, the spill has continued to surge toward disastrous proportions, and experts have warned of a possible nightmare scenario. Critical questions linger: Who created the conditions that caused the gusher? Did BP and the government react robustly enough in its early days? And, most important, how can it be stopped before the damage gets worse?
The Coast Guard and BP have said it's nearly impossible to know exactly how much oil has gushed since the blast, though it has been roughly estimated the well was spewing at least 200,000 gallons a day.
Even at that rate, the spill should eclipse the 1989 Exxon Valdez incident as the worst U.S. oil disaster in history in a matter of weeks.
The oil slick over the water's surface appeared to triple in size over the past two days, which could indicate an increase in the rate oil is pouring from the well, according to one analysis of images collected from satellites and reviewed by the University of Miami. While it's hard to judge the volume of oil by satellite because of depth, images do indicate growth, experts said.
"The spill and the spreading is getting so much faster and expanding much quicker than they estimated," said Hans Graber, executive director of the university's Center for Southeastern Tropical Advanced Remote Sensing.
In an exploration plan and environmental impact analysis filed with the federal government in February 2009, BP said it had the capability to handle a "worst-case scenario" at the site, which the document described as a leak of 162,000 barrels per day from an uncontrolled blowout – 6.8 million gallons each day.
And the situation could become far more grave if the oil gets into the Gulf Stream and carries it to the beaches of Florida – and potentially loops around the state's southern tip and up the eastern seaboard. Prime fishing waters, pristine beaches and countless wildlife could be ruined.
"It will be on the East Coast of Florida in almost no time," Graber said. "I don't think we can prevent that. It's more of a question of when rather than if."
Fishermen and boaters want to help but have been hampered by high winds and rough waves that render oil-catching booms largely ineffective. Some coastal Louisiana residents complained that BP was hampering mitigation efforts.
"No, I'm not happy with the protection, but I'm sure the oil company is saving money," said 57-year-old Raymond Schmitt, in Venice preparing his boat to take a French television crew on a tour.
The oil on the surface is just part of the problem. Louisiana State University professor Ed Overton, who heads a federal chemical hazard assessment team for oil spills, worries about a total collapse of the pipe inserted into the well. If that happens, there would be no warning and the resulting gusher could be even more devastating.
"When these things go, they go KABOOM," he said. "If this thing does collapse, we've got a big, big blow."
BP has not said how much oil is beneath the seabed Deepwater Horizon was tapping. A company official, speaking on condition of anonymity because he was not authorized to discuss the volume of reserves, confirmed reports that it was tens of millions of barrels.
Obama has halted any new offshore drilling projects unless rigs have new safeguards to prevent another disaster.
As if to cut off mounting criticism, on Saturday White House spokesman Robert Gibbs posted a blog entitled "The Response to the Oil Spill," laying out the administration's day-by-day response since the explosion, using words like "immediately" and "quickly," and emphasizing that Obama "early on" directed responding agencies to devote every resource to the incident and determining its cause.
In Pass Christian, Miss., 61-year-old Jimmy Rowell, a third-generation shrimp and oyster fisherman, worked on his boat at the harbor and stared out at the choppy waters.
"It's over for us. If this oil comes ashore, it's just over for us," Rowell said angrily, rubbing his forehead. "Nobody wants no oily shrimp."
Borenstein reported from Washington; Associated Press writers Tamara Lush, Brian Skoloff, Melissa Nelson, Mary Foster, Michael Kunzelman, Chris Kahn, Vicki Smith, Janet McConnaughey, Alan Sayre, Cain Burdeau and AP Photographer Dave Martin contributed to this report.