Chernobyl Release of radioactive materials Reaction of national authorities Radiation dose estimates Health impact Agricultural and environmental impacts Potential residual risks Conclusion Introduction On 26 April 1986, the Chernobyl nuclear power station, in Ukraine, suffered a major accident that was followed by a contamination of the surrounding area by the large quantities of radioactive substances. The specific features of the contamination favored a widespread distribution of radioactivity throughout the Northern Hemisphere, mainly across Europe. A contributing factor was the variation of meteorological conditions and wind regimes during the period of release. Activity trans