ITOPF maintains a worldwide database of accidental oil spills from tankers, combined carriers and barges. This is used to generate statistics on numbers and sizes of spills, and to identify causes of spills. It allows long-term trends to be analysed, which has proved useful for assessing the risk of oil spills for contingency planning, and for evaluating the possible consequences of changes in tanker design and operation. Using our GIS, spills can be displayed on maps and analysed alongside other datasets. For a number of high profile incidents, case histories and sources of further information are provided.