Presumably the people living nearby. Quite a bit of it isn't cleaned up; I've been to an atoll in the Pacific that I have to leave unnamed where you can still see rusting landing craft offshore.
As for oil, when it spills, the volatile component evaporates and the heavy component (tar) eventually sinks. If it sinks into the deep ocean, like every other organic material it'll eventually get broken down by bacteria. But that takes time.
Actually, if it sinks into the earth, the bacteria will eat it FASTER AND SOONER than they do in the ocean.
And the number 270,000 gallons of "spills" was oil, produced water, and other stuff. The probability is that 99+% of those "spills" were the produced water, and actual oil spillage was a very tiny fraction. A better way to enumerate it is how many ACRES of land were actually "contaminated" compared to the total size of the Kenai.