Tabun ( nerve agent ) Tabun or GA is an extremely toxic chemical substance . It is a clear , colorless , and tasteless liquid with a faint fruity odor . It is classified as a nerve agent because it fatally interferes with normal functioning of the mammalian nervous system . Its production is strictly controlled and stockpiling outlawed by the Chemical Weapons Convention of 1993 . Tabun is the first of the so - called " G - series " nerve agents along with GB ( sarin ) , GD ( soman ) and GF ( cyclosarin ) . Although pure tabun is clear , less - pure tabun may be brown . It is a volatile chemical , although less so than either sarin or soman . Tabun can be destroyed with bleaching powder , though the poisonous gas cyanogen chloride is produced . Synthesis . Tabun was made on an industrial scale by Germany during World War II , based on a process developed by Dr . Gerhard Schrader . In the chemical agent factory in Dyhernfurth an der Oder , codenamed " Hochwerk " , at least 12 , 000 metric tons of this agent were manufactured between 1942 and 1945 . The manufacturing process consisted of two steps , the first being reaction of gaseous dimethylamine ( 1 ) with an excess of phosphoryl chloride ( 2 ) , yielding dimethylamidophosphoric dichloride ( 3 , codenamed " Produkt 39 " or " D 4 " ) and dimethylammonium chloride ( 4 ) . The dimethylamidophosphoric dichloride thus obtained was purified by vacuum distillation and thereafter transferred to the main Tabun production line . Here it was reacted with an excess of sodium cyanide ( 5 ) , dispersed in dry chlorobenzene , yielding the intermediate dimethylamidophosphoric dicyanide ( not depicted in the scheme ) and sodium chloride ( 8 ) ; then , absolute ethanol ( 6 ) was added , reacting with the dimethylamidophosphoric dicyanide to yield tabun ( 7 ) and hydrogen cyanide ( 9 ) . After the reaction , the mixture ( consisting of about 75 % chlorobenzene and 25 % tabun , along with insoluble salts and the rest of the hydrogen cyanide ) was filtered to remove the insoluble salts and vacuum - distilled to remove hydrogen cyanide and excess chlorobenzene , so yielding the technical product , consisting either of 95 % tabun with 5 % chlorobenzene ( Tabun A ) or ( later in the war ) of 80 % tabun with 20 % chlorobenzene ( Tabun B ) . Effects of overexposure . The symptoms of exposure include : nervousness / restlessness , miosis ( contraction of the pupil ) , rhinorrhea ( runny nose ) , excessive salivation , dyspnea ( difficulty in breathing due to bronchoconstriction / secretions ) , sweating , bradycardia ( slow heartbeat ) , loss of consciousness , convulsion s , flaccid paralysis , loss of bladder and bowel control , apnea ( breathing stopped ) and lung blisters . The exact symptoms of overexposure are similar to those created by all nerve agent s . Tabun is toxic even in minute doses . The number and severity of symptoms which appear vary according to the amount of the agent absorbed and rate of entry of it into the body . Very small skin dosages sometimes cause local sweating and tremors accompanied with characteristically constricted pupils with few other effects . Tabun is about half as toxic as sarin by inhalation , but in very low concentrations it is more irritating to the eyes than sarin . Also , tabun breaks down slowly , which after repeated exposure can lead to build up in the body . The effects of tabun appear slowly when tabun is absorbed through the skin rather than inhaled . A victim may absorb a lethal dose quickly , although death may be delayed for one to two hours . A person ' s clothing can release the toxic chemical for up to 30 minutes after exposure . Inhaled lethal dosages kill in one to ten minutes , and liquid absorbed through the eye s kills almost as fast . However , people who experience mild to moderate exposure to tabun can recover completely , if treated almost as soon as exposure occurs . The LCt50 for tabun is about 400 mg - min / m Treatment for suspected tabun poisoning is often three injections of a nerve agent antidote , such as atropine . Pralidoxime chloride ( 2 - PAM Cl ) also works as an antidote ; however , it must be administered within a period of from minutes to a few hours following exposure to be effective . History . Tabun was the first nerve agent to be discovered by accident in January 1936 by the German researcher Gerhard Schrader . Schrader was experimenting with a class of compounds called organophosphate s , which kill insects by interrupting their nervous systems , to create a more effective insecticide for IG Farben , a German chemical and pharmaceutical industry conglomerate , at Elberfeld . Instead of a new insecticide , he discovered tabun , a chemical enormously toxic to humans as well as insects . During World War II , as part of the Grün 3 program , a plant for the manufacture of tabun was established at Dyhernfurth ( now Brzeg Dolny , Poland ) , in 1939 . Run by Anorgana , GmbH , the plant began production of the substance in 1942 . The reason for the delay was the extreme precautions used by the plant . Intermediate products of tabun were corrosive , and had to be contained in quartz or silver - lined vessels . Tabun itself was also highly toxic , and final reactions were conducted behind double glass walls . Large scale manufacturing of the agent resulted in problems with tabun ' s degradation over time , and only around 12 , 500 tons of material were manufactured before the plant was seized by the Soviet Army . The plant initially produced shells and aerial bombs using a 95 : 5 mix of tabun and chlorobenzene , designated " Variant A " , and in the latter half of the war switched to " Variant B , " a 80 : 20 mix of tabun and chlorobenzene designed for easier dispersion . The Soviets dismantled the plant and shipped it to Russia . During the Nuremberg Trials , Albert Speer , Minister of Armaments and War Production for the Third Reich , testified that he had planned to kill Adolf Hitler in early 1945 by introducing tabun into the Führerbunker ventilation shaft . He said his efforts were frustrated by the impracticability of tabun and his lack of ready access to a replacement nerve agent , and also by the unexpected construction of a tall chimney that put the air intake out of reach . The US once had a tabun production program , which ended many decades ago . Like the other Allied governments , the Soviets soon abandoned GA for GB and GD . Large quantities of the German - manufactured agent were dumped into the sea to neutralize the substance . Since GA is much easier to produce than the other G - series weapons and the process is comparatively widely understood , countries that develop a nerve agent capability but lack advanced industrial facilities often start by producing GA . During the Iran – Iraq War , Iraq employed quantities of chemical weapons against Iranian ground forces . Although the most commonly used agents were mustard gas and sarin , tabun and cyclosarin were also used .