Nerve+Agents

=**toc Nerve Agents**= =Definition= Nerve agents are organophosphate chemical weapons that interfere with normal nerve transmission and induce intense bronchial spasm with resulting inhibition of respiration. They are the most toxic of the known chemical agents, are toxic in their liquid or gaseous and can can cause death within minutes of exposure.

=Types of Nerve Agents=

Discovery
The G-Series of Nerve agents are so named because of their discovery by the German scientist Dr. Gerhard Schrader. Schrader began the discovery of these agents with his accidental discovery of the Tabun nerve agent on December 23, 1936. Although Dr. Schrader and his team of scientists hoped to create an insecticide that would end world hunger. Instead, he created one of the most deadly gases known to man. When he sprayed his compound of ethyl dimethyl-phosphoramido-cyanidate onto leaf lice, they died instantly. This was a surprisingly potent reaction considering only 5 parts per million were used in the Schrader's solution. Schrader and several of his asistants accidentally came into contact with the agent after a small drop of Tabun fell onto a workbench. Schrader and his assistants suffered contraction of the pupils (meiosis) and shortness of breath.

Historical Uses
The Germans in World War II manufactured large quantaties of Tabun, but were never able to use it in combat. Since then, it has been experimented with in several government agencies, but it has not been used in warfare, nor has any other nerve agent. From 1984 to 1985, United Nation Secretary General Javier Perez de Cuellar accused Iraq of using chemical weapons, including Tabun in its war versus Iran. This was later confirmed by a UN report. Around 5500 Iranians were estimated to have died in attacks with Tabun filled bombs. This was the first time that any nation used a nerve agent in combat. In March of 1988, Saddam Hussein's army attacked the city of Halabja in northern Iraq (Kurdistan), killing a large number of citizens. Tabun was included in the attack.

Production (Chemistry)
Tabun is the simplist nerve agents to produce, sythecized from four other chemicals: Phosphorus oxychloride (POCl3), sodium cyanide, dimethylamine and ethyl alcohol. The two step process used to create Tabun is not all that dangerous to the chemist. It involves mixing the ingredientes in a closed container with a sodium-hydroxide scrubbing system (rids the solution of the hydrochloric acid byproduct). Then the products must be transfered to an airtight container. The most difficult part of the reaction is containing the toxic hydrogen xyanide HCN gas during the crucial cyanation reaction.

Discovery
Sarin was discovered in 1938 and named after its discoverers. **S**chrader, **A**mbros, **R**udiger, Van der L**in**de. Later, the Germans built a plant in Dyernforth for the production of Sarin, but the government decided not to use chemical weapons and the plant was eventually captured by the Russians, who reopened the factory in 1946. Russia currently has a large supply of Sarin and other chemical weapons. Soman was discovered by Richard Khun in 1944.

Historical Uses
In 1950, the United Nations declared Sarin to be a "regular" chemical weapon and the United States began production. Some believe that the government currently has 5000 tons of Sarin stored throughout the country. Sarin was used against Iran in the Iran-Iraq war. Sarin was also used in the first ever nerve gas terrorist attack in Tokyo, 1995. Aum Shinrikyo, a radical cult group created by Shoko Asahara began its crusade against western civilizations with a trial attack on Tokyo. They released Sarin onto the city's subways, killing 12 people and injuring thousand. It has never been confirmed that Soman has been used for chemical warfare before.

Production (Chemistry)
Sarin and Soman are both created with the same basic steps. Both start with the compound phosphorus-trichloride. This material is then partially reacted with Hydrogen Fluoride, creating a solution that is half phosphorus-trichloride and half methylphosphonic dilluoride. The next step is different for Sarin and Soman. To make Sarin, Isopropyl alcohol is added to the mixture. To make Soman, pinacolyl alcohol is added. This is the only difference in the two.

V-Series
V-series agents are the most toxic of nerve agents. They are much more recently discovered than G-series agents and have never been used in combat. They are roughly ten times more deadly than Sarin.

Discovery
VX was first discovered by the British in 1954.

General Information
This is the most studied of the v-series gas, although lots of information is kept from the public about it. It does have a consistency similar to that of oil so VX is able to stay on the clothes or the body of the victim. That is the major difference between the V-series agents and the g-series agents.

There is not much known about the v-series agents, but most scientists agree that VE, VG, VM and VR all behave similarly to VX.

Effects
Nerve agents bind to the molecule acetylcholinesterase, which is responsible for stopping the movement of Acetylcholine in the central nervous system. Acetylcholine is an enzyme that controls muscle contraction. Since nerve agents create a situation where this enzyme never stops transmitting, muscles constantly and uncontrollably contract. Eventually they tire and muscles needed for respiration can no longer carry out their processes. This causes suffocation. According to the CDC, those exposed to nerve agents experience very similar symptoms. Victims may experience runny nose, watery eyes, small, pinpoint pupils, eye pain, blurred vision, drooling and excessive sweating, cough, chest tightness, rapid breathing, diarrhea, increased urination, confusion, drowsiness, weakness, headache, nausea, vomiting or abdominal pain, slow or fast heart rate, abnormally low or high blood pressure. All agents may have similar effects, but the time it takes for symptoms to set in may be different from one gas to the next.

Upon, contact with skin, nerve agents cause sweating and muscle twitching and large doses of them can cause loss of conciousness, convulsions, paralysis, respiratory failure, then death.

The toxicities of agents are shown below. LCt50 shows the estimated mass(mg) of a certain agent needed to become lethal for a cubic meter person in one minute. (mg- min/m^3) ICt50 shows incapacitation with the same units and MCt50 shows meiosis (contraction of the pupils).
 * Agent || LCt50 || ICt50 || MCt50 ||
 * Tabun || 400 || 300 || 2-3 ||
 * Sarin || 100 || 75 || 3 ||
 * Soman || 70 || UNK || <1 ||
 * VX || 50 || 35 || 0.04 ||

Works Cited"CBRNE - Nerve Agents, V-series - Ve, Vg, Vm, Vx: EMedicine Emergency Medicine." //EMedicine - Medical Reference//. Web. 05 June 2010. ."CDC | Facts About Sarin." //CDC Emergency Preparedness & Response Site//. Web. 05 June 2010. ."Chemical Weapons Programs - Iraq Special Weapons Facilities." //Federation of American Scientists//. Web. 05 June 2010. ."NERVE AGENTS." //Federation of American Scientists//. Web. 04 June 2010. ."Nerve Gas - Definition and More from the Free Merriam-Webster Dictionary." //Dictionary and Thesaurus - Merriam-Webster Online//. Web. 04 June 2010. ."Neuroscience for Kids - Nerve Agents." //UW Faculty Web Server//. Web. 04 June 2010. ."Sarin Gas Attack on the Tokyo Subway." //Japan-101.com - Japan Information Resource//. Web. 05 June 2010. .U.S. Congress, Office of Technology Assessment, Technologies Underlying Weapons of Mass Destruction, OTA-BP-ISC-115 (Washington, DC: U.S. Government Printing Office, December 1993).