Worst and Costliest accident in world history

"Always be alert! Avert the accident!"
An accident is defined as "an undesirable or unfortunate happening that occurs unintentionally and usually results in harm, injury, damage, or loss". Throughout the history, humans have always been prone to accidents. This thought induced us for the search of costliest accident in the world history. In-depth Google search concluded that on April 26, 1986, the world witnessed the costliest accident in history. The Chernobyl disaster has been called the biggest socio-economic catastrophe in peacetime history at the Chernobyl Nuclear Power Plant in Ukraine (then in the Ukrainian Soviet Socialist Republic, part of the former Soviet Union). It is considered the worst nuclear power plant accident in history .
On April 26, 1986, reactor number four at the Chernobyl plant, near Pripyat in the Ukrainian Soviet Socialist Republic, had a meltdown. The resulting fire sent a plume of radioactive fallout into the atmosphere and over an extensive geographical area, including the nearby town of Pripyat. The plume drifted over large parts of the western Soviet Union, Eastern Europe, Western Europe, and Northern Europe. Large areas in Ukraine, Belarus, and Russia had to be evacuated, with over 336,000 people resettled. According to official post-Soviet data, about 60% of the fallout landed in Belarus.
The countries of Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and health care costs of the Chernobyl accident. A 2005 report prepared by the Chernobyl Forum, led by the International Atomic Energy Agency (IAEA) and World Health Organization (WHO), attributed "fewer than 50" direct deaths (including nine children with thyroid cancer) and estimated that there may be up to 4,000 additional cancer deaths over time among the approximately 600,000 most highly exposed people. Although the Chernobyl Exclusion Zone and certain limited areas remain off limits, the majority of affected areas are now considered safe for settlement and economic activity.



The total costs including cleanup, resettlement, and compensation to victims has been estimated to be roughly $200 Billion. The cost of a new steel shelter for the Chernobyl nuclear plant will cost $2 billion alone. The accident was officially attributed to power plant operators who violated plant procedures and were ignorant of the safety requirements needed.

Sources: Wikipedia, the History Channel, and the Discovery Channel.