This paper reviewed the environmental consequences reported in more than three thousand accidents. Fifty-nine of the accidents reported environmental consequences, seven reported no environmental consequences, and for the remaining accidents, no information was available. Generally, the properties of a chemical, the dilution of the amount released, and the environmental conditions at the spill site are the parameters that determine the short-term environmental consequences. To evaluate the long-term effects, which have almost never been studied in the accidents reviewed, persistence, the tendency to accumulate in sediment and biota, and the long-term sub-lethal and chronic effects are the main parameters to be considered. While ecological consequences of accidents have been investigated more frequently in recent years, there has been no consistency in reporting methodology. An accident investigation methodology and a reporting format should therefore be developed and implemented on a broad international scale.