Tabun or GA (Ethyl N,N-dimethylphosphoramidocyanidate) is an extremely toxic substance that is one of the world's most dangerous military weapons. Because it fatally interferes with normal functioning of the mammalian nervous system, it is classified as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations according to UN Resolution 687, and its production is strictly controlled and stockpiling outlawed by the Chemical Weapons Convention of 1993.