the invention is a closed - loop , thermal process for remediating soil contaminated with hydrocarbon chemicals ; it is particularly well suited for the remediation of soils containing hydrocarbons with relatively high boiling points and for the remediation of soils which contain clays or silts . the process uses a combination of at least one extraction well which is used to withdraw vapors from contaminated soil and at least one injection well , called a &# 34 ; fire &# 34 ; well which is used to burn both a source of hydrocarbon fuel and all of the hydrocarbons present in the recovered vapors and then inject the combustion gases into contaminated soil . the heat in the combustion gases is used to raise the temperature of the contaminated soil and volatilize hydrocarbons in the soil . dielectric heating can be used to supplement the heating performed by the combustion gases .