Worst land pollution

Thousands of tonnes of crude oil flowed across the pristine Arctic tundra of the Komi Republic in Russia from August to September 1994 in what is known as the Usinsk accident.  Estimates of the amount of oil lost vary from 14,000 to 200,000 tonnes and the total contaminated area measuring 21,100,000 m²  (227,118,509 ft²).  This is almost the same area as that occupied by the country El Salvador in Central America.  The cost of the accident was estimated at more than 311 billion roubles (US$11 billion, £7,500 million).      The technical cause of the Usinsk accident was the poor condition of the pipes which transported the oil from the oil plants to an oil refining plant.  There were several ruptures and spills between July-October but these were kept hidden from the public by the federal and local authorities and KomiNeft, the oil company.  The official date of the incident is 17 August 1994 and it wasn't investigated until a special commission was set up in November 1994.