The effectiveness and potential pollutional effects of chemicals and other materials used to disperse, sink, burn or otherwise dissipate oil slicks are discussed. Agents considered are classed as; dispersants, floating sorbents, sinking agents, gelling agents and burning agents. Since many dispersants are presently available, much experience has been gained with the use of dispersants. However, dispersants should not be used indiscriminately, they may have deleterious effects on the ecology. It is necessary to determine the toxicity and the effectiveness of dispersants viz-a-viz the same characteristics of the oil without dispersants. Practical experience with gelling, burning, floating and sinking agents is limited. Some of the many commercial products and natural materials used in connection with recent large oil spills are reported. (Author)