Click on the map to enlarge.
THE DIRTY ZONE: Within a month of the April 26, 1986, Chornobyl explosion, Soviet authorities had evacuated almost 120,000 people from a zone within 30 kilometers of the plant. However, contamination by radioactive isotopes, particularly cesium-137, which has a half-life of 30 years, spread over a much wider area.
The map above shows the four areas of cesium-137 contamination across Belarus, Russia, and Ukraine. The Closed Zone shows contamination more than 40 curies per square kilometer, the Control Zone includes the Permanent Control Zone (15-40 curies per square kilometer) and Periodic Control Zone (5-15 curies per square kilometer), and the Unnamed Zone shows contamination of 1-15 curies per square kilometer.