>"It could take officials months to assess and mitigate some of the damage from a major oil spill off the coast of Southern California. In a worst-case scenario, oil could linger for years to come."

Once it’s in a habitat like this, there’s a lot of sediment that gets transported there until eventually the oil will be sequestered by the sediment. It’s sort of landfilled. Once it’s landfilled deep enough, oxygen will not get to it, and it’s the oxygen exposure and the sunlight that actually weathers oil. So once it’s below the oxygen line, it’ll degrade extremely slowly. It will probably be there for decades.