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Sarin has a relatively short shelf life, and will degrade after a period of several weeks to several months. The shelf life may be greatly shortened by impurities in precursor materials. According to the CIA , in 1989 the Iraqis destroyed 40 or more tons of sarin that had decomposed, and that some Iraqi sarin had a shelf life of only a few weeks owing mostly to impure precursors.
Like other nerve agents, Sarin can be chemically deactivated with a strong alkali. Typically an 18 percent aqueous solution of sodium hydroxide is used to destroy Sarin.
Efforts to lengthen shelf life
According to the CIA, nations such as Iraq have tried to overcome the problem of sarin's short shelf life in two ways:
The shelf life of unitary (i.e., pure) sarin may be lengthened by increasing the purity of the precursor and intermediate chemicals and refining the production process.
Incorporating a stabilizer chemical called tributylamine. Later this was replaced by diisopropylcarbodiimide (di-c-di), which allowed for GB nerve agent to be stored in aluminum casings.
Developing binary chemical weapons, where the two precursor chemicals are stored separately in the same shell, and mixed to form the agent immediately before or when the shell is in flight. This approach has the dual benefit of making the issue of shelf life irrelevant and greatly increasing the safety of sarin munitions "
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