Second opinion: Residual oil under foundation after supply pipe cut

[jthoni]

I posted this on another sites forums:
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Our house had an oil furnace at some point in the distant past. By the time I bought it (7 years ago) it had been converted to gas. The supply line from the external tank had just been left stubbed out of the basement floor. I am in the process of finishing the basement, and we relocated the furnace. My contractor cut open the foundation, and clipped the stub off. There was some residual oil in the line that leaked out. It trickeled for a while, and he cleaned it up. A week later or so he patched the hole with self-leveling compound. All has been fine in the 5 or 6 months since then. I was doing some cleaning of the floor (we have not yet carpeted) this weekend, when I noticed a slight discoloration (about 3" diameter). When I get my nose to within 3" or so, I can smell heating oil. My guess is that one of the following happened:

A) There was a little more oil that leached into the self-leveling compound when it was wet.
B) The pipe continued to leak a bit, and has saturated up through the floor.

I would tend to lean toward A as you have to get real close to smell it (when we first were cleaning up, the whole basement stunk), and this was 5 or 6 months, and there is only the small spot.

I am trying to figure out what to do next. I am guessing that I could either put some kind of seal coat on to make sure that no fumes come out, or break it open and make sure all is OK (clean up, make sure there is a good crimp/cap in the pipe, etc.).

My questions are:

1) Which seems most likely (i.e. A or B).
2) What should I do about it? If there is a small amount of oil under there (remember, the pipe had stopped draining, even when completely open), could it present any fumes that are hazardous? Can you even seal something like this?
3) If I wanted someone to come and do this, would I call someone who specializes in furnace decomissioning?

Thanks!
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I got just the one reply:
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Obviously we are talking about a very small (probably less than a pint) of oil in total. That small amount presents no hazzard to your health or the environment. Most likely there was still a small amount left in the pipe which leached out after he did his patch job.
To clean up the stain, try putting clay absorbent (kitty litter) on it & grind it in with your foot. Leave for a day or so & sweep it up. If there is any discoloration of the absorbent, repeat until no further discoloration is seen. Until the oil is gone, you are not going to be able to seal over it.
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Just looking to see if there is anyone here that supports/refutes this reply.

Thanks!

[HayZee518]

kerosene or fuel oil had always been used as a release agent for concrete work. it forms a film that just stays there it doesn't evaporate. if you could cut it with another solvent the odor will disappear. try using a shop vac to suck up whatever is left in the line if you have access to it. use a solvent that air dries without a residue. you may be able to get concrete to bond to it then.