|You really don't know. I have a buddy i work with that had to go to the clinic for PI. He had it for 3 days until he did something about it. Well, i know i can't get it from him unless there is oil on something he may have touched and not cleaned off. Well, i had to come in contact with something that had oil on it becuase i have broken out. I'm thinking a door handle or some tools i borrowed from him. So, its really important to scrub everything that may have had the transfer of oil to it. So, the oil can still be in the tub or the tiles, etc... I guess to be safe, you would have to bleach it. (Only if you think you may have spread the oil in the area.)
I also got it once by kicking off my boots. I was real careful in taking them off and cleaning them, but i must have gotten it from the laces. Caught it a week later.
The oil can last up to a long time, so cleaning everything you can think of would be the best precaution.
Fun stuff, eh?