Interesting. I did not know that.
Oil takes a long time to evaporate in warm conditions- I have a drum that is not sealed, sitting in my garage for nearly 3 months.... still quite full of oil
I have no concept of how long it might take to stop harming the environment if dissolved w/ soap.... so I'm not disputing your claim.
Either way, I think that we can both agree that the key is to keep it out of the water in the first place!