The Chernobyl disaster was a catastrophic nuclear accident that occurred in 1986 at the Chernobyl Nuclear Power Plant in Ukraine. Due to design flaws and human error, reactor number 4 exploded and burned, releasing large amounts of radioactive material into the atmosphere. The explosion and fires immediately killed two workers and forced the evacuation of over 100,000 people from the surrounding area. Long-term, the disaster caused many cases of radiation poisoning and increased cancer rates in the affected population and environment.