SAG/SDAG Wismut was a uranium mining company in East Germany during the time of the cold war. It produced a total of 230,400 tonnes of uranium between 1947 and 1990 and made East Germany the fourth largest producer of uranium ore in the world at the time. It was the largest single producer of uranium ore in the entire sphere of control of the USSR. In 1991 after German reunification it was transformed into the Wismut GmbH company, owned by the Federal Republic of Germany, which is now responsible for the restoration and environmental cleanup of the former mining and milling areas. The head office of SDAG Wismut / Wismut GmbH is in Chemnitz-Siegmar.
The Ore Mountains (German: Erzgebirge; Czech: Krušné hory) in southern East Germany at the border with the Czech Republic are closely connected to the history of uranium exploitation. The metal was discovered in a sample from a silver mine in the mountain range, and uranium was produced first as a by-product in the early 19th century and later as a main product from the 1890s on. The chemists Marie and Pierre Curie discovered the elements Radium and Polonium in pitchblende tailings from a Czech uranium mine in these mountains. Radioactive waters were used in several towns for health treatment.
After World War II, the Soviet Union became interested in this East German uranium deposit as a source for its nuclear weapons program. Significant resources were discovered and mining started in 1946. In 1947 the Soviet stock company Wismut (SAG Wismut) was formed, named after the German word for the metal bismuth, the misleading name being selected for security reasons. In the following years the company became the most important source of uranium for the Soviet Union and it employed several tens of thousands of people. Safety and environmental standards were very low, with reported deaths of up to 1,281, and another 20,000 suffering injuries or health issues in a 6-month period alone.