The main objective of the present report is to support Nordic Countries with environmental impact assessments of accidental oil spills in Nordic areas, in the work to control and reduce the cause of these effects. The Nordic Seas have specific habitats with specialised key-species which have different sensitivities to oil spills. This report studies the short- and long-term effects of accidental oil spills in these habitats. Birds and questionably marine mammals are under greatest threat from both short- and long-term effects. The plankton community will also be affected, but is quickly re-established. The impact on pelagic fish is negligible in short term but not in a long time perspective, and benthic fauna will be practically unaffected by short-term effects. They can however in a long-term suffer significantly from settled oil slicks. In the foreseeable future the number of minor oil spills is likely to increase, as will the risk for major accidents. Thus there is a strong need for mapping and identifying important and sensitive species and habitat. With senistivity atlases for the Nordic seas and coastal areas precautious measures can be implemented to reduce the magnitude of the short- and long term impact from an oil spill