Soil material contaminated with hydrocarbons can be cleaned by supercritical water extraction. Due to the high critical data of supercritical water(T-c = 647 K, P-c = 22.1 MPa), supercritical carbon dioxide (T-c = 304 K, P-c = 7.3 MPa) was investigated as an alternative solvent. The amount of hydrocarbons removed from weathered contaminated soil material with supercritical carbon dioxide was less than 21%.