Wash a sink of dishes with Dawn (the same degreasing used in BP leak) and let it sit for several hours. Drain the water and feel the bottom of the sink, it will be covered with grease because it breaks it down, then it sinks.
Now imagine the bottom of the Gulf.
The volume of oil released into the gulf by the BP oil spill was proportionally the same as a large can of beer poured into a pro football stadium filled with water. I would defy you to find any evidence of the beer.