A method for in-situ dense non-aqueous phase liquids treatment in which a subsurface source area comprising at least one rapid release contaminant is located and free water removed therefrom. The subsurface source area is then heated to a temperature suitable for extracting the at least one rapid release contaminant from the subsurface source area. The at least one rapid release contaminant is extracted from the subsurface source area, resulting in solidification of the dense non-aqueous phase liquids remaining in the subsurface source area.