Traces of nerve and mustard gas have been found at Karshi Khanabad air base in Uzbekistan. The for former Soviet Air Force base is being used by a thousand coalition troops to support efforts in Afghanistan. The trace elements are not enough to make anyone ill, and are probably the result of some long ago (the Soviets left in the early 1990s) accident with chemical weapons carried in bombs. Uzbekistan contains extensive uninhabited areas that were probably used by the Soviets to test chemical weapons bombs.