The Deepwater Horizon drilling rig caught fire and sank in the Gulf of Mexico, leaving 11 crew members missing. The rig was drilling an exploratory well for BP in over 5,000 feet of water under contract with Transocean. Investigators believe oil and gas may have entered the wellbore undetected, escaping pressures and igniting on the rig. Efforts to control the still-flowing well using remote operated vehicles from support vessels have so far been unsuccessful. Specialized equipment will be needed to drill a relief well to intercept and stop the flow of oil from the damaged well.