Previous nuclear incidents and accidents: Chernobyl

On 26 April 1986 the world's most severe nuclear reactor accident occurred in Chernobyl, Ukraine (at that time part of the Soviet Union). An area of about 5 million hectares - almost the size of Nova Scotia - was contaminated and 160,000 people had to be permanently evacuated. Radioactive material affected not only the Ukraine but also neighbouring countries and parts of Western Europe.

The Chernobyl accident demonstrated the need to include the possibility of trans-boundary implications in national emergency plans. The concern that any country could be affected not only by nuclear accidents occurring within its own territory but also by the consequences of accidents happening abroad, stimulated the establishment of national emergency plans in several countries. Also, the trans-boundary nature of the contamination resulting from the Chernobyl accident prompted international organizations to promote international cooperation and communication, to harmonize actions, and to develop international emergency exercises such as the Nuclear Energy Agency's INEX series. The international community reached agreements on early notification in the event of a radiological accident and on assistance in radiological emergencies through international conventions developed by the International Atomic Energy Agency.