NEW ORLEANS -- Coast Guard, Plaquemine Parish Port Authority and Homeland Security units provide an escort as the blowout preventer of the Deepwater Horizon is transported on the Mississippi River into New Orleans, Sept. 11, 2010. The blowout preventer will be used to help the joint BOEM/USCG investigation determine the circumstances surrounding the explosion, fire, pollution, and sinking of the Mobile Offshore Drilling Unit Deepwater Horizon. U.S. Coast Guard photo by Petty Officer 3rd Class Stephen Lehmann.