Final Criminal Trial for Deepwater Horizon Begins

The final criminal trial stemming from the Deepwater Horizon spill is under way, with opening arguments and witness testimony regarding the actions of one of two BP drilling supervisors aboard the rig at the time of the blowout.

The defendant, former day supervisor Robert Kaluza, is charged with a negligent Clean Water Act violation for his actions prior to the spill. The crew of the rig had conducted a negative pressure test of the well to assess whether cement at the bottom had formed a proper seal between the well and the surrounding resevoir, prosecutors say, and the government contends that Mr. Kaluza and co-defendent Donald Vidrine – who pled guilty – allegedly ignored “multiple indications that the well was not secure” and declared the tests successful, without consulting shoreside experts.

Following the test, Kaluza halted work on the well and went off duty, leaving further decisions to Vidrine; under Vidrine's supervision, the drilling crew proceeded with displacement, in which the drilling mud in the well's riser was replaced with seawater. With an ineffective cement plug at the bottom of the well – something the negative pressure test should have revealed, the government says – the seawater in the riser allowed oil and gas to ascend until it reached the rig's drill floor, where it ignited, causing an explosion.

That event and the subsequent fire and spill in April 2010 resulted in 11 deaths, the burning and sinking of the Deepwater Horizon, the largest oil spill in U.S. history and total economic damages yet to be determined. BP has set aside $55 billion for compensation related to the spill.

In pre-trial filings, the prosecutors expected that Kaluza's defense would center on the importance of factors other than his evaluation of the negative pressure test, including decisions made by Vidrine and onshore engineer Mark Hafle. Defense attorney Shaun Clarke told jurors in opening statements Thursday that Kaluza had been temporarily filling in at the time, had left the decision to the more experienced Vidrine, and that the primary reason for the spill was the failure of a blowout preventer which had not been maintained for years beyond its standard service interval.

In testimony Friday, Mr. Vidrine told the court that Mr. Kaluza had not passed on key information about the negative pressure test when he went off duty, and that Mr. Kaluza never expressed concern about its results.

If convicted, Mr. Kaluza faces a sentence of up to one year's imprisonment. His trial is expected to be the last criminal case related to the disaster.

Charges of manslaughter against Kaluza and Vidrine have been dropped; all other prosecutions of individual company officers to date have resulted in acquittals, except for one misdemeanor guilty plea with no jail sentence. BP and Transocean pled guilty to charges of Clean Water Act violations; BP also pled guilty to manslaughter and obstruction of Congress, and reached a final settlement of $18 billion with the EPA for violations and damages related to the spill.