Like the CEOs of failing car companies and steroid-suspected baseball players before them, the leaders of BP, Transocean, and Halliburton had to trek up to Capitol Hill today to stand before Congress. The three company executives played circle-of-blame in front of the Senate Energy and Natural Resources Committee. To sum up their statements:

BP: It was Transocean’s fault.

Transocean: It was Halliburton’s fault.

Halliburton: It was BP’s fault.

Since we may not know the whole story about the Deepwater Horizon’s explosion and sinking that resulted in the current environmental disaster in the Gulf, let’s recap the technical failures.

1. Blowout preventer

This piece of equipment, previously anonymous to most of the public, is now notorious for its failure to do its job—closing off the well automatically in response to a sudden emergency. Lamar McKay, president and chairman of BP America, used that fact to deflect blame:

Since Transocean owned the rig’s safety equipment, Mr. McKay said that Transocean was responsible; he added that there were “anomalous pressure test readings” before the explosion that “could have raised concerns” [The New York Times].

However, just after the accident, BP’s CEO Tony Heyward said that a blowout preventer’s failure was “unprecedented.” Not exactly, according to the AP’s investigation, which found many examples of accidents this decade in which failed blowout preventers played a role. Transocean knew about the issues, the AP says, but so did the federal government.

In the late 1990s, the industry appealed for fewer required pressure tests on these valves. The federal [Minerals Management Service] did two studies, each finding that failures were more common than the industry said. But the agency, known as MMS, then did its turnaround and required tests half as often. It estimated that the rule would yield an annual savings of up to $340,000 per rig. An industry executive praised the “flexibility” of regulators, long plagued with accusations that it has been too cozy with the industry it supervises [AP].

2. Cementing

OK, Transocean chief executive Steve Newman said, there was a blowout preventer failure, but that was not the root cause of the explosion or the leak.

“The one thing we know with certainty is that on the evening of April 20 there was a sudden, catastrophic failure of the cement, the casing, or both,” Newman said. The cementing job was done by Halliburton [The Washington Post].

In fact, Halliburton was still working on its cementing job 20 hours before the explosion.

There was already a pipe in the well for the oil to flow through, but no oil was supposed to flow yet. Cementing, one of the last steps in well construction, seals the crack between the pipe and the wall of rock. Crews pump the cement through the pipe, but it ends up on the outside of the pipe, in the space between the pipe and the rock wall. The cement also caps the bottom of the pipe [NPR].

Cementing could go bad if the material isn’t mixed to the correct consistency. If any oil and gas leaks out early, NPR reports, it can cause a pocket in the cement that doesn’t seal up. And if cement doesn’t set properly, oil and gas could escape the well and even explode.

3. Oversight, and response failures

While Transocean owned the rig and Halliburton poured the concrete, this was BP’s show. And, so, the other two companies also employed the “just following orders” defense.

Halliburton was “contractually bound,” to follow BP’s instructions, Tim Probert, president of global business lines for the Houston-based energy services company, will tell the panel.

“All offshore oil and gas production projects begin and end with the operator,” Stephen Newman, chief executive officer of Swiss drilling company Transocean said in his prepared remarks. BP, the London-based oil company, decided “where and how” its well was to be drilled, Newman said [BusinessWeek].

Whatever BP’s failures were in administering the the drilling operation and preventing an accident (and those will most likely continue to leak out, like oil into the Gulf), the company’s attempts to mitigate the spill have met with limited success. BP’s initial attempt to shut of the flow, using robot submersibles to close of the valves, has failed. After the company built its 100-ton containment dome to try to capture the flow and pump it to a tanker on the surface, icy buildup of methane and water at the depth of 5,000 feet prevented the dome from getting a seal.

The methane that caused the original explosion remains gaseous down to -161°C. The “ice” that’s forming is actually a solidified mixture of methane and water called a clathrate [Ars Technica].

Faced with dwindling options and still two months before a relief well could be completed, BP is even considering throwing garbage at the leak in the form of a “junk shot” in a last-ditch effort to stem the flow.

“They have horribly underestimated the likelihood of a spill and therefore horribly underestimated the consequences of something going wrong,” said Robert Bea, a professor at the University of California, Berkeley, who studies offshore drilling. “So what we have now is some equivalent of a fire drill with paper towels and buckets for cleanup” [Dallas Morning News].

Previous posts on the BP oil spill:
80beats: 5 Offshore Oil Hotspots Beyond the Gulf That Could Boom—Or Go Boom
80beats: Gulf Oil Spill: Do Chemical Dispersants Pose Their Own Environmental Risk?
80beats: Gulf Oil Spill: Fisheries Closed; Louisiana Wetlands Now in Jeopardy
80beats: Gulf Oil Spill Reaches U.S. Coast; New Orleans Reeks of “Pungent Fuel Smell”
80beats: Uh-Oh: Gulf Oil Spill May Be 5 Times Worse Than Previously Thought

Image: U.S. Coast Guard