"Oil Industry's answers frustrate federal panel"
"The lead investigator examining the Deepwater Horizon disaster appears to be losing patience with vague or nonresponsive responses from oficials including a BP vice president.
"Since the hearings began in May, three BP officials with intimate knowledge of events leading up to the April 20 explosion ....have declined to trestify before a joint Coast Guard and Interior Department panel, which convened again Wednesday. .....Two invoked their constitutional right not to produce testimony that could incriminate themselves."...........
Coast Guard lead inestigator expressed particular agitation at answers given by BP vice president for drilling Harry Thierens, ......" Thierens could not recall any details about past accidents at Thunderhorse (Gulf area).
"Investigators were also dissatisfied about the confusing chain of command aboard the rig.
"Thierens said he lacked a "thorough understanding" of the command structure, a response that left Nguyen unhappy.
"Someone has got to be in charge," Nguyen said about the three-legged stool command aboard the rig.
Thierens testified that he was not notified of changes made in the blowout preventer.... "the changes hampered efforts to take control of the well, he said."

In other testimony, a Transocean supervisor denied testimony by rig electronics technician Mike Williams.
Los Angeles Times, August 26, 2010.