A nickname for "ethyl dimethylphosphoramidocyanidate" (wish I knew what it means
:). Commonly refered to as GA.
Tabun is a nerve gas developed by a german scientist Gerhard Schrader on 23th December 1936, while working on insecticides. Consequentially, this was the first nerve agent to be discovered.
Not only did Gerhard observe the extreme poisonousness of the substance on leaf lice, but also had an opportunity at trying Tabun first hand, when he and his assistant were exposed to a small amount of it. Their pupils immediately contracted to tiny pinholes and they suffered shortness of breath, being lucky to escape before it was too late.
Being a loyal citizen, Gerhard Schrader reported his discovery to the german military (as it was required by the law for any discovery having military importance).
Fortunatelly for Britain, whose intelligence apparently wasn't aware of the new deadly gas, it wasn't used during World War II. It was sheer luck for Britain not to involve chemical weapons (thus not triggering a deadly German response) despite PM Winston Churchill 's eagerness to use them (not knowing the potential of German Tabun, which penetrated through the skin, making British gas masks powerless against it).
The gas interferes with the transmission of nerve impulses across synapses, thus causing the victim to loose control of his body. Finally, the victim looses control over breathing, causing suffocation.