This photo from a U.S. District Court filing shows a sample of pipe from a pipleine at the Prudhoe Bay oil field on Alaska's North Slope obtained by the U.S. government after the March 2006 oil spill, showing about 6 inches of sediment built up on the bottom of the pipe. BP Exploration Alaska Inc. is scheduled to plead guilty Thursday, Nov. 29, 2007, in U.S. District Court in Anchorage, Alaska, to one violation of the Clean Water Act for a 200,000-gallon crude oil spill at the Prudhoe Bay field in March 2006. (AP Photo/U.S. District Court filing)

Read Article