Actually, no. Even low grade sarin, made of impure precursors, will keep for a few weeks, but back when chemical weapons were a thing, a lot of nations kept sarin in unitary state, adding stabilizer chemicals, like tributylamine and diisopropylcarbodiimide. Nations with access to better technology kept it in binary state, because it was safer, but that required more complicated mechanism of deployment.
Even US kept both unitary and binary sarin. In the preparation for the Gulf War, CIA wrote a report that concluded that "CIA ANALYSTS BELIEVE THAT THE SHELF LIFE PROBLEM WAS ONLY TEMPORARY AND THAT THE IRAQIS CAN NOW PRODUCE UNITARY AGENTS OF SUFFICIENT QUALITY BY ADDING A STABILIZER OR IMPROVING THE PRODUCTION PROCESS."
Sarin used by terrorists is usually of low-grade, unitary kind (like in Tokyo terror attack) because they lack the expertise and technology to keep it binary and make effective firing mechanism. The unitary sarin has simple deployment - destroy the container and gas gets released.
Well, he is really not a resident Syrian.More properly our Assyrian in America.
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