the current case, when an oil rig explodes or is damaged. The explosion and sinking of an oil rig in the middle of the Gulf of Mexico on Tuesday has created a potentially serious environmental situation, though experts are not sure how bad it might be. That all depends on whether the oil from the rig’s well spills and where it goes. Oil spills cause a very localised problem but can be catastrophic to local marine wildlife such as fish, birds and sea otters. Oil spills make up about 12% of the oil that enters the ocean. The rest come from shipping travel, drains and dumping.