Oil is seen on the surface of the Gulf of Mexico as BP tries to stop oil leaking from the Deepwater Horizon wellhead in the Gulf of Mexico 55 miles (89 km) south of Port Fourchon, Louisiana May 8, 2010. BP Plc engineers positioned a four-story metal chamber above a gushing, ruptured oil well on the seabed of the Gulf of Mexico on Saturday in an unprecedented effort to contain a possibly catastrophic spill. REUTERS/Sean Gardner (UNITED STATES - Tags: DISASTER ENVIRONMENT IMAGES OF THE DAY)