File photo shows Greenpeace activists painting over a banner with the BP logo in Vienna, during a protest against the Deepwater Horizon gulf oil spill in the Gulf of Mexico

 
File photo shows Greenpeace activists painting over a banner with the BP logo in Vienna, during a protest against the Deepwater Horizon gulf oil spill in the Gulf of Mexico
Greenpeace activists paint over a banner with the British Petroleum (BP) logo at St. Stephen's square in Vienna, during a protest against the Deepwater Horizon gulf oil spill in the Gulf of Mexico in this July 7, 2010 file photo. When BP's Deepwater Horizon oil rig exploded and sank in the Gulf of Mexico last April, killing 11 workers, authorities first reported that no crude was leaking into the ocean. They were wrong. One year on, oil from the largest spill in U.S. history clogs wetlands, pollutes the ocean and endangers wildlife, not to mention the toll it has inflicted on the coastal economies of Florida, Mississippi, Alabama and especially Louisiana. REUTERS/Lisi Niesner/Files (AUSTRIA - Tags: ANNIVERSARY BUSINESS CIVIL UNREST DISASTER ENERGY ENVIRONMENT)