Exxon is still alive and well, so there must be something there.
I've observed that environmentalists never get their panties in a knot over natural underwater oil seeps, of which there are many.The natural underwater oil seeps in the Gulf of Mexico crank out between 1 and 5 million barrels every single year. By comparison, the Exxon Valdez spill was about half a million barrels.
There are a bunch of underwater oil seeps on the Alaskan North Slope as well, dumping straight into the Beaufort Sea.