Laborers' International Union of North America (LiUNA) hold up signs in support of the Keystone XL pipeline during a rally in Washington, D.C., U.S., on Friday, Oct. 7, 2011. BP Plc's oil spill in the Gulf of Mexico helped fuel environmentalists' opposition to TransCanada Corp.'s Keystone XL pipeline, the company's chief executive officer said. TransCanada plans to build a 1,661-mile (2,673-kilometer) line to transport Canadian oil from Alberta to Texas refineries. Photographer: Andrew Harrer/Bloomberg via Getty Images