Environmental problems of long standing plague the nuclear weapons industry. Besides soil and water contamination by radioactive materials, some sites suffer contamination by conventional hazardous chemicals used in the production process.
In the second half of this century the USA nuclear weapons industry has manufactured nearly 70,000 nuclear warheads. It has produced about 89 tonnes of plutonium and more than 500 tonnes of highly enriched uranium, the primary radioactive material in nuclear weapons. Decades of activity at the US Department of Energy nuclear weapons laboratory, production and test facilities have left an estimated 4,500 contaminated sites covering tens of thousands of hectares of land. Efforts to clean them up and bring nuclear weapons facilities into compliance with the nation's environmental laws are expected to take at least 30 years and cost more than $200 billion.
In the USA in 1990 it was also reported that as many as 42 of the 177 underground tanks that are used to store waste from nuclear bomb production are in danger of exploding. Such an explosion could mean the spread of toxic chemicals and radioactive materials over large areas. The risk is due to unforeseen reactions between the chemicals stored and those introduced in an endeavour to consolidate the waste. The ferrocyanide percolating in the tanks is sufficient to cause an explosion equivalent to 36 tons of TNT. In 1957 in the USSR, the explosion of such a nuclear waste storage tank spread radiation over a large area and forced the evacuation of 10,000 people, with some reports that hundreds of people later died. It was also reported that 28 kg of plutonium (equivalent to 7 nuclear bombs) had escaped into the air ducts at the Rocky Flats weapons plant during its 30 years of operation, although it is so toxic that it is usually accounted for in gram quantities.