Following the Torrey Canyon disaster, attention was directed to finding effective but innocuous means to combat the pollution risk of shipping oil. To introduce the minimum of chemicals into the sea, it was decided to use a little of a strong, but possibly more harmful, substance rather than more of a weaker and less offensive one. Marine life could be affected mechanically, chemically or by removal or dissolved O sub(2). Various products were tested under laboratory conditions for effectiveness, and possible effects on marine life. It is noted that the latter is only a short-term view, and that different results might be obtained using different species as indicators. The range of effectiveness of products was considered. It was concluded that low density products should be sought as emulsifiers; solvents of low boiling point were best for viscous petrols; relative solubility in sea water was not a determining factor of efficiency; anionic detergents, polyglycol ethers and perchlorethylene should be avoided because of their toxicity.