KENNER, La. - Mike Williams, a Transocean chief engineer tech, swears in before his testimony at the Deepwater Horizon joint investigation hearing, July 23, 2010. The Coast Guard and the Bureau of Ocean Energy Management, Regulation, and Enforcement (BOEM) are co-chairing a joint investigation launched to determine the cause of the initial incident and fire aboard the mobile offshore drilling unit (MODU) Deepwater Horizon. U. S. Coast Guard photo by Senior Chief Petty Officer Mike O'Berry.