HOUSTON, Aug. 24 (Xinhua) -- U.S. federal investigators are hearing testimonies from BP and Transocean officials in a probe into the cause of the rig explosion that led to the massive oil spill in the Gulf of Mexico.
The hearings, jointly conducted by the U.S. Coast Guard and Bureau of Ocean Energy Management, Regulation and Enforcement, started Monday and will continue through Friday in Houston.
BP's Gulf of Mexico marine authority official Neil Cramond, the first witness Monday, testified that Transocean's Deepwater Horizon had dozens of maintenance issues in an audit conducted seven months before the rig blast.
BP had recommended a five-day suspension of operations on the rig after the audit but later recommended that the rig be put back into service even though not all the issues had been addressed.
Paul Johnson, the Transocean rig manager who supervised the Deepwater Horizon's drilling operation from land, said later at the hearing that he had doubt about Robert Kaluza, the BP well- site leader sent to the rig just days before explosion.
Johnson said he challenged BP on its decision to appoint Kaluza as the well-site leader because he had concerns over the latter's knowledge of drilling rigs like the Deepwater Horizon. BP assured him that Kaluza was experienced, Johnson said.
Questions had been raised about BP's decision to proceed with temporarily abandoning its Macondo well in the Gulf of Mexico even though negative pressure tests revealed abnormal pressures in the well.
However, Daun Winslow, a Transocean performance division manager who was aboard the rig during the accident, testified at Tuesday's hearing that nothing led him to believe conditions were unsafe aboard the rig prior to the blast.
He also said he didn't feel that a visit to the Deepwater Horizon rig by two Transocean officials and two BP executives interfered in any way with operations the day of the accident.
The first two days of hearings also revealed a confusion over the leadership aboard the Deepwater Horizon when the explosion happened.
When U.S. Coast Guard Capt. Hung Nguyen asked Johnson if he was clear about "who was in charge" during the accident, Johnson said he was not sure.
Asked if he knew the importance of a clear leadership during an emergency, Johnson said: "I never gave it much thought."
The Deepwater Horizon rig exploded April 20 off the Louisiana coast, killing 11 workers and unleashing the worst spill in U.S. history.