BP Executive Expected to Be First Trial Witness A BP executive is expected to be the first witness to testify at a trial next month designed to identify the causes of a deadly rig explosion that spawned a massive oil spill in the Gulf of Mexico in 2010. In a court filing Tuesday, plaintiffs' lawyers said BP America Chairman and President Lamar McKay is the first witness they intend to call after the trial's opening statements. They also intend to call Mark Bly, BP's executive vice president for safety and operational risk, during the first week of a trial scheduled to start Feb. 27. U.S. District Judge Carl Barbier will preside over the three-phase trial without a jury. He oversees tens of thousands of claims spawned by the April 20, 2010, explosion of the Deepwater Horizon oil rig.