Samples of 3 (sandy, mountain and peat) soils (100 g) were contaminated with diesel oil and then placed sep. in pipes (diam. 50 mm) with a perforated bottom. Soil samples without impurities were similarly prepd. Then all samples were treated with Hp or an aq. soln. of a com. extinguishing agents (250 mL) to det. changes in their water retention capacity. The contents of selected polycyclic arom. hydrocarbons in soil samples were det by mass chromatog. coupled to a mass spectrometer. Water retention in the soils significantly depended on the type of soil and the extinguishing agent used.