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BP Set for "Top Kill" as Disenchantment Grows

Updated at 7:05 p.m. ET

Five weeks after a massive oil spill that has fouled the Gulf coast and caused confusion about who is ultimately responsible for the containment efforts, BP is poised to launch its latest attempt to plug the troublesome leak.

BP engineers said they have the equipment in place to try a complicated procedure - known as a "top kill" - that they hope will seal the blown-out Gulf of Mexico oil well. The company hopes to launch the effort on Wednesday and will soon start 12 hours of tests to prepare for the maneuver, BP PLC senior vice president Kent Wells.

The procedure involves pumping heavy drilling mud into a massive device on top of the gushing well. Wells said it could be delayed if there's any snag in the tests.

Special Section: Disaster in the Gulf

The top kill has proven successful in aboveground wells, but has never before been tried a mile beneath the sea. Company executives peg its chances of success at 60 to 70 percent.

Engineers are working on several other backup plans in case the top kill doesn't work, including injecting assorted junk into the well to clog it up, and lowering a new blowout preventer on top of the one that failed.

The only certain permanent solution is a pair of relief wells crews have already started drilling, but the task could take at least two months.

In Barataria Bay, La., Julie Lasseigne's family oyster crop, numbering in the tens of thousands, was poisoned by oil, CBS News Correspondent Mark Strassmann reports.

"I'm mad as hell because my children have no future now," she told CBS News.

Her family has fished the waters there for five generations.

The prospects of a successful operation come as public disenchantment with both BP and the government's handling of the crisis has increased. According to a new CBS News poll, 70 percent of Americans disapprove of BP's handling of the disaster, compared with just 18 percent who approve. More people are dissatisfied with the U.S. government's efforts than not, by a mark of 45 percent to 35 percent.

The falling public opinion comes during a week where confusion reigned over one central question: Who's in charge?

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Since the beginning, the government has insisted that BP is responsible for the spill's cleanup.

"BP is the responsible party, they own the well, they're responsible for capping it," Gibbs told "Face the Nation" host Bob Schieffer Sunday.

But BP's chief operating officer Don Suttles said Monday that "the federal government does have ultimate control of this event."

The back and forth continued throughout the day, with the administration's point man on the spill rejecting the notion of removing BP and taking over the crisis Monday, saying the government has neither the company's expertise nor its deep-sea equipment.

"To push BP out of the way would raise a question, to replace them with what?" Coast Guard Commandant Thad Allen, who is heading the federal response to the spill, said at a White House briefing.

On Tuesday, the White House sought to clarify the confusion. Carol Browner, the president's assistant for energy and climate change, said the "government is in charge" but it relies on BP's technical expertise to execute the response.

"We have been in charge and we'll continue to be in charge. But clearly BP has expertise and that needs to be brought to bear. At the same time, we're bringing to bear our best expertise," she told "Early Show" co-anchor Harry Smith.

Meanwhile, BP is focused on two key areas around the blown wellhead as it probes the cause of the unchecked spill, the company said as it started to brief federal authorities on its internal investigation.

BP PLC said in a release late Monday that it has not reached a final conclusion. But it said multiple control mechanisms should have prevented the accident that started with an oil rig explosion April 20 off the coast of Louisiana.

The largest oil and gas producer in the Gulf listed seven mechanisms where its hunt for a cause is focused. Four of those involve the blowout preventer, a massive piece of machinery that sits atop the wellhead and is supposed to act as a safety device of last resort. The other three areas of investigation involve the cementing and casing of the wellhead.

An illustration of BP's top kill procedure. The company says the primary objective is to put heavy kill mud into the well so that it reduces the pressure and then the flow from the well.

Three companies were involved with BP on the well: Transocean LTD owned the Deepwater Horizon oil rig and the blowout preventer; Halliburton Inc. was responsible for encasing the well in cement; and Cameron International Corp. manufactured the blowout preventer.

President Barack Obama has blasted executives from the companies for blaming each other during Congressional hearings this month.

In BP's release, Chief Executive Tony Hayward stopped short of assigning responsibility, calling the disaster "a complex accident, caused by an unprecedented combination of failures."

"A number of companies are involved, including BP, and it is simply too early - and not up to us - to say who is at fault," Hayward said.

BP said its investigation team has begun sharing its findings with the U.S. Department of the Interior.

BP said there was still extensive work to do in its investigation, including examining major pieces of equipment like the blowout preventer and the rig that are still on the seafloor.

The internal investigation started the day after the rig exploded, burned and sank. It is being conducted by BP's Head of Group Safety and Operations, who has an independent reporting line to Hayward, the company said.

In related news:

Live video of the Gulf of Mexico oil spill shows the underwater plume getting significantly darker. A top oil engineering expert says that suggests heavier, more-polluting oil is spewing out.

The color of the oil gushing from the main pipe has changed in color from medium gray to black. Two scientists noticed the change, which oil company BP downplayed as a natural fluctuation that is not likely permanent.

But engineering professor Bob Bea at the University of California at Berkeley says the color change may indicate the BP leak has hit a reservoir of more oil and less gas. Gas is less polluting because it evaporates. Bea has spent more than 55 years working and studying oil rigs.

Oil has been spewing from the site of the Deepwater Horizon oil rig that exploded April 20.

A memorial service was scheduled for Tuesday afternoon in Jackson, Mississippi, for the 11 workers who were killed when the oil rig exploded. The event was being held by Transocean.

A new Interior Department report says staffers at an agency that oversees offshore drilling accepted tickets to sports events, lunches and other gifts from oil and gas companies and used government computers to view pornography.

In at least one case, an inspector for the Minerals Management Service admitted using crystal methamphetamine and said he might have been under the influence of the drug the next day at work, according to the report by the acting inspector general of the Interior Department.

The report follows up on a 2007 investigation that revealed what then-Inspector General Earl Devaney called a "culture of ethical failure" and conflicts of interest at the minerals agency.

Interior Secretary Ken Salazar called the latest report "deeply disturbing" and said it highlights the need for reforms he has proposed, including a plan to abolish the minerals agency and replace it with three new entities.

The report "is further evidence of the cozy relationship between some elements of MMS and the oil and gas industry," Salazar said Tuesday. "I appreciate and fully support the inspector general's strong work to root out the bad apples in MMS."

Salazar said several employees cited in the report have resigned, were fired, or referred for prosecution. More employees may be fired, disciplined or referred for criminal prosecution as warranted, Salazar said.

Salazar stressed that the report by Mary Kendall, Interior's acting inspector general, applied to actions taken between 2000 and 2008. He said he has asked Kendall to expand her investigation to look into agency actions since he took office in January 2009.

After butting heads with BP over its use of a chemical to break up the oil in the water, the Obama administration said Tuesday the company is complying with the government's request to use less of the toxic dispersant.

White House energy adviser Carol Browner said alternative dispersants aren't so readily available.

In a letter to BP last week, the Environmental Protection Agency gave the company three days to find a less toxic alternative to the dispersant it's using, Corexit 9500. But in a series of meetings that followed, Browner said, it became clear the alternatives were not as widely available as needed.

"There are not as many being manufactured as people thought in the quantities" needed, Browner said in a round of television appearances on morning news shows.

"We need to determine whether or not those alternatives are available, and the EPA is doing that, but in the meantime, EPA has directed BP to use less of the dispersants and they're required to follow that," Browner said.