The bare-knuckles litigation over who's to blame for the Deepwater Horizon disaster took a dramatic turn yesterday when BP PLC accused Halliburton Co. of destroying what could be crucial evidence.

BP and contractors Halliburton and Transocean Ltd. were all involved in the Macondo well-drilling operation in the Gulf of Mexico that led to the April 20, 2010, explosion and related oil spill. They are now locked in a court battle in the Eastern District of Louisiana over how liability will be apportioned (Greenwire, April 21).

A trial is scheduled to begin in February.

Halliburton's role as the cement contractor on the well has already been highlighted by the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling.

One of the report's findings was that Halliburton had conducted tests in February 2010 that indicated the foam cement slurry used on the well was unstable.

BP has been desperate to get access to Halliburton's internal documents and computer modeling results in relation to the slurry testing.

Yesterday's accusation in a court filing was prompted by BP's failure to get what it wanted.

The oil company claimed in the filing that Halliburton "destroyed the results of physical slurry testing, and it has, at best, lost the computer modeling outputs."

On the slurry testing, BP said Halliburton "intentionally destroyed the evidence ... in part because it wanted to eliminate any risk this evidence would be used against it at trial."

In responding to requests about the computer modeling data, Halliburton said only that it was "gone," BP said.

BP has asked U.S. District Judge Carl Barbier to order "forensic efforts to recover the missing data" and, if it cannot be found, allow BP to probe further into how it was lost.

Such moves "are essential to ensure the court's trial is not tainted by Halliburton's misconduct," BP said.

Halliburton has consistently defended its work on the Macondo well and has said BP should take the blame for what happened. BP, for example, skipped tests that might have raised questions about the cement used, the company has said (Greenwire, Oct. 29, 2010).

In a statement, a Halliburton spokesman said the "conclusions that BP is asking the court to draw is without merit and we look forward to contesting their motion in court."

Rena Steinzor, an environmental law professor at the University of Maryland School of Law, expressed no surprise at the latest development in the litigation.

"It's pretty predictable this would happen," she said. "They are fighting a battle to the death over a lot of money."

Steinzor said BP's latest filing is also likely to pique the attention of the Justice Department, which has filed a civil complaint against BP and other contractors -- not as yet including Halliburton -- over the spill.

The Clean Water Act penalties alone could range from $5.4 billion, based on a minimum $1,100-per-barrel fine, to as much as $21.1 billion, or $4,300 per barrel, if the spill is deemed to be the result of "gross negligence."

The Justice Department also has an ongoing criminal investigation.

Click here to read BP's filing.