It may not be as clean as you think. If your current home or the one you are purchasing has an underground oil storage tank you might consider having a qualified professional look into it. Many homes that were built prior to 1980 utilized above ground or underground storage tanks. The tanks are usually constructed of steel and over time the metal gets corroded and holes can form in the tank causing the oil to leak directly into the soil. More information can be found here.
I recently helped a client purchase a home and it was determined during our inspection period that had it an oil tank. We called an environmental group that specializes in this field so that they could test the soil. The results revealed that the tank had a leak and the that the tank should be removed. Here’s a sneak peek at the process!