> >Maaybe the most practical answer is to do both . . . >dig up and throw away the soil that seems the most contaminated >and dig in composted organic material to the whole general area. > > Bill
If the soil is heavily contaminated with petroleum products you can not legally
just dig it up and throw it away. It has to go to a hazardous waste site where
they will either put it in a very expensive Haz dump, or a very expensive Haz
incinerator.
The other option is to send it to a land farm where they will mix it with other
soil in the open, run a disk over it daily for about a month and sell it as
clean dirt.
The petroleum contaminates either evaporate or are consumed by naturally
occuring microbes when it is exposed to air and sunlight.
If it were mine, I would do the compost thing or simulate the land farm and
till it up every few days for a month or so. It will likely be fine after
either one.