Experiments have been made in the field to determine the way in which fuel oil No. 1 spreads in some common unconsolidated deposits in Sweden, such as esker material, bottom varves of glacial clay and sand on clay. In the investigations, the velocity of fuel No. 1 in reasonably homogeneous medium sand with a good ground water flow was found to be 1.0–1.6 m/day, but usually the velocity was as low as 0.1–0.2 m/day. Experiments covering a longer period showed that the maximum concentration diminished very much in transport up to a distance of about 20 m.