Abstract: A method and apparatus for decontaminating soil that has been contaminated with vaporizable contaminants are disclosed. Contaminated soil is conveyed through a treatment vessel by means of an auger that has internal passages therein with a hot heat transfer fluid flowing through such passages. As the contaminated soil passes through the treatment vessel, it is heated to a point where the contaminants are vaporized and are withdrawn from the treatment vessel. The vaporized contaminants can be processed in suitable equipment to safely recover or dispose of such contaminants. Air is added to the interior of the treatment vessel from the atmosphere. Appropriate control means are present for controlling the amount of air added to the treatment vessel to ensure that the oxygen level in the mixture of vaporized contaminates and air does not fall within a flamable or explosive range. Following the vaporization of the contaminates from the soil, the thus treated soil is removed from the treatment vessel.