This is an interesting infographic that could influence an oil spill graph. The sinking ship idea is pretty swagger.
This graphic is interesting. You could do an oil spill theme by having similar graphics in grey scale with heaver blacks and bolder strokes representing years that had more oil spills.
If I want to go with the endangered species graphics this is good inspiration. It has the vector images I wanted to do. I don't think this is the whole graphic so it's a bit hard to understand, but it I believe it's saying that there is 1 of these animals to the given number of humans. Crazy.