Top executives at British Petroleum (BP) America and other firms involved in the catastrophic Gulf Coast oil spill last month appeared before a Congressional Subcommittee on Oversight and Investigations hearing Wednesday titled Inquiry into the Deepwater Horizon Gulf Coast Oil Spill.

Faced by a skeptical audience of lawmakers the executives gave an update on the status of their efforts to mitigate the effects of the spill and pledged to fully cooperate with investigations to determine the causes of the spill.

Lamar McKay, Chairman & President, BP America, said that his company’s efforts are focused on two overarching goals, stopping the flow of oil and minimizing the impact on the environment.

McKay reported that BP’s subsea efforts to stop the flow of oil and secure the well have involved working to activate the blow-out preventer (BOP) on the well and using a containment system placing large enclosures or containment chambers atop the leaks.

Unfortunately, he acknowledged, these efforts have so far not proved successful.

“There have been technical challenges,” McKay said, referring to his company’s containment system. “This system has never been used before at 5,000 feet. Engineers are now working to see if these challenges can be overcome.”

McKay also reported that BP was attacking the spill on both the open water and the shoreline, through the activation of its pre-approved spill response plans.

“On the open water,” he said, “ we have mobilized a fleet of 294 response vessels, including skimmers, storage barges, tugs, and other vessels. The Hoss barge, the world's largest skimming vessel, has been onsite since Apri[ 25. [n addition, there are 15, 210-foot Marine Spill Response Corporation Oil Spill Response Vessels, which each have the capacity to collect, separate, and store 4000 barrels of oil. To date, over 97,000 barrels of oil and water mix have been recovered.”

McKay added that BP was attacking the spill area with US Coast Guard approved biodegradable dispersants, which are being applied from both planes and boats. Dispersants are soap-like products which help the oil to break up and disperse in the water, which, in tum, helps speed natural degradation.

Steven Newman, Chief Executive Officer, of Transocean Ltd., a drilling rigs operatior and partner of BP North America in the Gulf, attacked the notion that the blowout preventers (or BOPs) used on the Gulf project were the cause of the accident.

“That simply makes no sense,” Newman insisted . “A BOP is a large piece of equipment positioned on top of a wellhead to provide pressure control… BOPs are designed to quickly shut off the flow of oil or natural gas by squeezing, crushing or shearing the pipe in the event of a “kick” or “blowout” – a sudden, unexpected release of pressure from within the well that can occur during drilling.”

Tim Probert, President, Global Business Lines and Chief Health, Safety and Environmental Officer of Halliburton on eof the world’s largest oil services companies, said that his company had secured the well through a procedure called “cementing” and that the well had passed a key pressure test.

The executives’ assessments were countered by skepticism from the Subcommittee chairs.

“The more I learn about this accident, the more concerned I become,” Rep. Henry A. Waxman (D-CA), Chairman, Committee on Energy and Commerce said. “This catastrophe appears to have been caused by a calamitous series of equipment and operational failures. If the largest oil and oil services companies in the world had been more careful, 11 lives might have been saved and our coastlines protected.”

Rep. Bart Stupak (D-CA), the Subcommittee’s other Chairman, argued that evidence points to dysfunction and possibly negligence on the part of all the companies involved.

“ Our investigation is at its early stages, but already we have uncovered significant problems with the blowout preventer used on the Deepwater Horizon drill rig,” Stupak said.

Stupak explained that the blowout preventer apparently had a significant leak in a key hydraulic system and also that the blowout preventer had been modified in unexpected ways.

Stupak said that the blowout preventer was not powerful enough to cut through joints in the drill pipe. Finally Stupak said that evidence is mounting that the emergency controls on the blowout preventer may have failed.