WASHINGTON -- Top executives from three companies involved in the Deepwater Horizon oil rig disaster will face a barrage of questions Tuesday on Capitol Hill. Angry senators are eager to make it clear they intend to hold someone responsible for a blowout that killed 11 workers and continues to spew 210,000 gallons of oil each day into the Gulf of Mexico.
But it's also clear the three companies will have another source of finger-pointing -- each other.
In testimony released Monday before the first of Tuesday's two Senate hearings, the executives, from BP America, which owned the well, Transocean Ltd., which owned the rig, and Halliburton, a contractor on the rig, blame the other companies for the as-yet-undetermined cause of the explosion.
Also Tuesday, Interior Secretary Ken Salazar will hold a news conference to announce reforms that would ``toughen inspections and oversight of offshore oil and gas operations,'' according to a statement released by the federal agency.
Meanwhile, in New Orleans, a two-day public hearing into the events surrounding the April 20 explosion begins at 9 a.m.. The investigation is being conducted jointly by the Minerals Management Service, which regulates the oil industry, and the U.S. Coast Guard.
The public inquiries come at a time when BP is struggling to stop the flood of oil and authorities in Louisiana prepare for the likely arrival of a massive oil slick along the state's marshy shoreline.
BP officials call their latest effort to stop the leak a ``top hat'' and say engineers could try to place it over the main leaking pipe as early as Thursday.
The oil captured inside would then be pumped to a barge on the surface. The strategy is similar to BP's failed weekend effort to place a massive 78-ton steel and concrete cofferdam the size of a four-story house over the pipe, but the ``top hat,'' just four feet in diameter and five feet tall, is the size of a shed.
BP officials said the small size should help avoid the formation of the slushlike hydrates that thwarted the earlier cofferdam effort by clogging the cofferdam's opening and making it too buoyant to form a watertight seal against the sea floor.
To make certain, the ``top hat'' will be warmed with hot water and injected with methanol, a solvent whose use under water required EPA approval.
``The rationale is there will be less seawater in the smaller dome, and therefore less likelihood of hydrate formation,'' BP Group CEO Tony Hayward said.
BP engineers plan to follow that effort with a so-called ``junk shot,'' which foresees shooting shredded tires, golf balls and knotted rope into the well at high pressure to clog it and stop the flow. That effort won't be ready for two weeks, however.
In Washington, Lamar McKay of BP, in prepared testimony to the Senate Energy and Natural Resources Committee, said the company wants to answer two questions at the root of the disaster: What caused the explosion and fire, and why did the blowout preventer fail? He makes it clear Transocean owned the blowout preventer.
``The systems are intended to fail-closed and be fail-safe. Sadly and for reasons we do not yet understand, in this case, they were not,'' McKay is to testify. ``Transocean's blowout preventer failed to operate.''
That directly counters Transocean CEO Steven Newman's statement.
``Over the past several days, some have suggested that the blowout preventers used on this project were the cause of the accident,'' Newman is expected to testify. ``That simply makes no sense.''
Their investigative team has looked at numerous possible causes, Newman will say, but the company's blowout preventers ``were clearly not the root cause of the explosion.'' The well had been sealed with casing and cement, and within a few days, the blowout preventers would have been removed, anyway. At that point, the cementing and casing were responsible for controlling any pressure, he says in his testimony.
Although Newman does not single out Halliburton for blame, he does make it clear that Halliburton was the cementing subcontractor -- and as such ``is responsible for encasing the well in cement, or putting a temporary cement plug in the top of the well, and for ensuring the integrity of the cement.''
Tim Probert of Halliburton has a different take, and points back to BP in his prepared testimony. The well owner is ultimately responsible, said Probert, who is the president of the company's global business lines and its chief health, safety and environmental officer.
``I need to start this section with an important statement of disclosure,'' he is expected to testify. ``Halliburton, as a service provider to the well owner, is contractually bound to comply with the well owner's instructions on all matters relating to the performance of all work-related activities.
``It is also important to understand the roles and responsibilities of the various parties involved in the construction of a well,'' he added. ``The construction of a deep water well is a complex operation involving the performance of numerous tasks by multiple parties led by the well owner's representative, who has the ultimate authority for decisions on how and when various activities are conducted.''
Regardless of who is to blame for the accident, McKay said in his prepared testimony that he wishes to underscore BP's ``intense determination to do everything humanly possible to minimize the environmental and economic impacts of the resulting oil spill on the Gulf Coast.''
Already, the company has mobilized a fleet of 294 response vessels and has recovered more than 97,000 barrels of oil-and-water mix from the sea, McKay said in his statement.
``BP is under no illusions about the seriousness of the situation we face,'' he said. ``In the last three weeks, the eyes of the world have been upon us. President Obama and members of his Cabinet have visited the Gulf region and made clear their expectations of BP and our industry. So have members of Congress, as well as the general public.''
In reaction to the rig explosion and oil spill, Obama has temporarily halted all new offshore drilling until the Interior Department submits a safety report due May 28.