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37-495: Pine Bluff Arsenal stored 90,409 M55 GB rockets, 19,608 M55 VX rockets, 9,378 M23 VX landmines and 3,705 mustard ton containers. It was also the home for the Binary Chemical Weapons Facility. The facility created one of the two toxic agents that would combine to form sarin . Construction of the diphenylcyanoarsine (DC) facility began in the mid-1980s and a classified number of canisters were produced. A facility

74-499: A covalent bond with the particular serine residue at the active site. Fluoride is the leaving group , and the resulting organo-phosphoester is robust and biologically inactive . Its mechanism of action resembles that of some commonly used insecticides , such as malathion . In terms of biological activity, it resembles carbamate insecticides, such as Sevin , and the medicines pyridostigmine , neostigmine , and physostigmine . Controlled studies in healthy men have shown that

111-491: A delay ranging from hours to several weeks, in cases where exposure is limited but no antidote is applied. Sarin has a high volatility (ease with which a liquid can turn into vapour) relative to similar nerve agents, making inhalation very easy, and may even absorb through the skin. A person's clothing can release sarin for about 30 minutes after it has come in contact with sarin gas, which can lead to exposure of other people. Treatment measures have been described. Treatment

148-504: A direct comparison to the respiratory LCt 50 : Sarin is a chiral molecule because it has four chemically distinct substituents attached to the tetrahedral phosphorus center. The S P form (the (–) optical isomer ) is the more active enantiomer due to its greater binding affinity to acetylcholinesterase . The P-F bond is easily broken by nucleophilic agents, such as water and hydroxide. At high p H , sarin decomposes rapidly to nontoxic phosphonic acid derivatives. It

185-460: A longer period after exposure than the methods described above. Fluoride reactivation is a technique that has been explored since at least the early 2000s. This technique obviates some of the deficiencies of older procedures. Sarin not only reacts with the water in the blood plasma through hydrolysis (forming so-called 'free metabolites'), but also reacts with various proteins to form 'protein adducts'. These protein adducts are not so easily removed from

222-496: A non-lethal dose and do not receive immediate medical treatment may suffer permanent neurological damage. Sarin is widely considered a weapon of mass destruction . Production and stockpiling of sarin was outlawed as of April 1997 by the Chemical Weapons Convention of 1993, and it is classified as a Schedule 1 substance . Like some other nerve agents that affect the neurotransmitter acetylcholine , sarin attacks

259-587: A nontoxic 0.43 mg oral dose administered in several portions over a 3-day interval caused average maximum depressions of 22 and 30%, respectively, in plasma and erythrocyte acetylcholinesterase levels. A single acute 0.5 mg dose caused mild symptoms of intoxication and an average reduction of 38% in both measures of acetylcholinesterase activity. Sarin in blood is rapidly degraded either in vivo or in vitro . Its primary inactive metabolites have in vivo serum half-lives of approximately 24 hours. The serum level of unbound isopropyl methylphosphonic acid (IMPA),

296-426: A sarin hydrolysis product, ranged from 2–135 μg/L in survivors of a terrorist attack during the first four hours post-exposure. Sarin or its metabolites may be determined in blood or urine by gas or liquid chromatography , while acetylcholinesterase activity is usually measured by enzymatic methods. A newer method called "fluoride regeneration" or "fluoride reactivation" detects the presence of nerve agents for

333-431: A short shelf life. Therefore, it is usually stored as two separate precursors that produce sarin when combined. Sarin's shelf life can be extended by increasing the purity of the precursor and intermediates and incorporating stabilizers such as tributylamine . In some formulations, tributylamine is replaced by diisopropylcarbodiimide (DIC), allowing sarin to be stored in aluminium casings. In binary chemical weapons ,

370-474: A synthetic acetylcholine antagonist , has been suggested as an alternative to atropine due to its better blood–brain barrier penetration and higher efficacy. Sarin is a potent inhibitor of acetylcholinesterase , an enzyme that degrades the neurotransmitter acetylcholine after it is released into the synaptic cleft . In vertebrates, acetylcholine is the neurotransmitter used at the neuromuscular junction, where signals are transmitted between neurons from

407-508: A weapon). IMPA then degrades into methylphosphonic acid (MPA), which can also be produced by other organophosphates. Sarin with residual acid degrades after a period of several weeks to several months. The shelf life can be shortened by impurities in precursor materials . According to the CIA , some Iraqi sarin had a shelf life of only a few weeks, owing mostly to impure precursors. Along with nerve agents such as tabun and VX , sarin can have

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444-410: Is 172 μg/kg. Sarin is highly toxic, whether by contact with the skin or breathed in. The toxicity of sarin in humans is largely based on calculations from studies with animals. The lethal concentration of sarin in air is approximately 28–35 mg per cubic meter per minute for a two-minute exposure time by a healthy adult breathing normally (exchanging 15 liters of air per minute, lower 28 mg/m value

481-492: Is a cholinesterase inhibitor, hence increases the concentration of acetylcholine present). Some of the symptoms of increased cholinergic stimulation include: Cholinergic crisis, sometimes known by the mnemonic "SLUDGE syndrome" ( S alivation, L acrimation, U rination, D efecation, G astrointestinal distress and E mesis), can be a consequence of: Some elements of the cholinergic crisis can be reversed with antimuscarinic drugs like atropine or diphenhydramine , but

518-426: Is almost always manufactured as a racemic mixture (a 1:1 mixture of its enantiomeric forms) as this involves a much simpler synthesis while providing an adequate weapon. A number of production pathways can be used to create sarin. The final reaction typically involves attachment of the isopropoxy group to the phosphorus with an alcoholysis with isopropyl alcohol . Two variants of this final step are common. One

555-423: Is an extremely toxic organophosphorus compound . A colourless, odourless liquid , it is used as a chemical weapon due to its extreme potency as a nerve agent . Exposure can be lethal even at very low concentrations, where death can occur within one to ten minutes after direct inhalation of a lethal dose, due to suffocation from respiratory paralysis, unless antidotes are quickly administered. People who absorb

592-708: Is for general population). This number represents the estimated lethal concentration for 50% of exposed victims, the LCt 50 value. The LCt 95 or LCt 100 value is estimated to be 40–83 mg per cubic meter for exposure time of two minutes. Calculating effects for different exposure times and concentrations requires following specific toxic load models. In general, brief exposures to higher concentrations are more lethal than comparable long time exposures to low concentrations. There are many ways to make relative comparisons between toxic substances. The list below compares sarin to some current and historic chemical warfare agents, with

629-399: Is the most toxic of the four G-Series nerve agents made by Germany. The compound, which followed the discovery of the nerve agent tabun , was named in honor of its discoverers: chemist Gerhard S chrader , chemist Otto A mbros , chemist Gerhard R itter  [ de ] , and from Heereswaffenamt Hans-Jürgen von der L in de. In mid-1939, the formula for the agent was passed to

666-431: Is the reaction of methylphosphonyl difluoride with isopropyl alcohol, which produces a racemic mixture of sarin enantiomers with hydrofluoric acid as a byproduct: The second process, known as the "Di-Di" process, uses equimolar quantities of methylphosphonyl difluoride (Difluoro) and methylphosphonyl dichloride (Dichloro). This reaction gives sarin, hydrochloric acid and others minors byproducts. The Di-Di process

703-447: Is typically with the antidotes atropine and pralidoxime . Atropine, an antagonist to muscarinic acetylcholine receptors , is given to treat the physiological symptoms of poisoning. Since muscular response to acetylcholine is mediated through nicotinic acetylcholine receptors , atropine does not counteract the muscular symptoms. Pralidoxime can regenerate cholinesterases if administered within approximately five hours. Biperiden ,

740-603: The chemical warfare section of the German Army Weapons Office , which ordered that it be brought into mass production for wartime use. Pilot plants were built, and a production facility was under construction (but was not finished) by the end of World War II . Estimates for total sarin production by Nazi Germany range from 500 kg to 10 tons. Though sarin, tabun , and soman were incorporated into artillery shells, Germany did not use nerve agents against Allied targets. Adolf Hitler refused to initiate

777-527: The nervous system by interfering with the degradation of the neurotransmitter acetylcholine at neuromuscular junctions . Death usually occurs as a result of asphyxia due to the inability to control the muscles involved in breathing. Initial symptoms following exposure to sarin are a runny nose , tightness in the chest, and constriction of the pupils . Soon after, the person will have difficulty breathing and experience nausea and drooling. This progresses to losing control of bodily functions, which may cause

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814-491: The peripheral nervous system to muscle fibres. Normally, acetylcholine is released from the neuron to stimulate the muscle, after which it is degraded by acetylcholinesterase , allowing the muscle to relax. A build-up of acetylcholine in the synaptic cleft , due to the inhibition of acetylcholinesterase, means the neurotransmitter continues to act on the muscle fibre, so that any nerve impulses are effectively continually transmitted. Sarin acts on acetylcholinesterase by forming

851-495: The Pine Bluff Integrated Production Facilities (IBPF) was completed and no filling of the air-delivered binary bomb ever took place. The Army only produced a few of these bombs. They remained empty or filled with a safe, simulated chemical for test purposes. International treaty inspectors witnessed the destruction of all these bombs in the summer of 1999. The Pine Bluff Chemical Agent Disposal Facility

888-420: The body, and remain for a longer period of time than the free metabolites. One clear advantage of this process is that the period, post-exposure, for determination of sarin exposure is much longer, possibly five to eight weeks according to at least one study. As a nerve gas, sarin in its purest form is estimated to be 26 times more deadly than cyanide . The LD 50 of subcutaneously injected sarin in mice

925-416: The chemical itself, various additives have been tried to combat the effects of the acid, such as: Another byproduct of these two chemical processes is diisopropyl methylphosphonate , formed when a second isopropyl alcohol reacts with the sarin itself and from disproportionation of sarin, when distilled incorrectly. The factor of its formation in esterification is that as the concentration of DF-DCl decreases,

962-409: The concentration of sarin increases, the probability of DIMP formation is greater. DIMP is a natural impurity of sarin, that is almost impossible to be eliminated, mathematically, when the reaction is a 1 mol-1 mol "one-stream". This chemical degrades into isopropyl methylphosphonic acid. The most important chemical reactions of phosphoryl halides is the hydrolysis of the bond between phosphorus and

999-408: The concomitant use of atropine along with cholinesterase inhibitor medication in order to prevent side effects. Flaccid paralysis resulting from cholinergic crisis can be distinguished from myasthenia gravis by the use of the drug edrophonium (Tensilon), as it only worsens the paralysis caused by cholinergic crisis but strengthens the muscle response in the case of myasthenia gravis. (Edrophonium

1036-545: The final substitution is selective for chloro over fluoro as the leaving group . Inert atmosphere and anhydrous conditions ( Schlenk techniques ) are used for synthesis of sarin and other organophosphates. As both reactions leave considerable acid in the product, sarin produced in bulk by these methods has a short half life without further processing, and would be corrosive to containers and damaging to weapons systems. Various methods have been tried to resolve these problems. In addition to industrial refining techniques to purify

1073-413: The fluoride. This P-F bond is easily broken by nucleophilic agents, such as water and hydroxide . At high pH , sarin decomposes rapidly to nontoxic phosphonic acid derivatives. The initial breakdown of sarin is into isopropyl methylphosphonic acid (IMPA), a chemical that is not commonly found in nature except as a breakdown product of sarin (this is useful for detecting the recent deployment of sarin as

1110-550: The last remaining chemical weapons on site. Workers began destruction of mustard agent-filled ton containers in December 2008. The facility reached 100% destruction of its total chemical stockpile of 3,850 metric tons on November 12, 2010. The facility and Pine Bluff Chemical Activity finalized closure in January 2014. Sarin Sarin ( NATO designation GB [short for G-series , "B"])

1147-407: The most dangerous effect - respiratory depression, cannot. The neuromuscular junction, where the brain communicates with muscles (like the diaphragm , the main breathing muscle), works by acetylcholine activating nicotinic acetylcholine receptors and leading to muscle contraction. Atropine only blocks muscarinic acetylcholine receptors (a different receptor class than the nicotinic receptors at

Pine Bluff Chemical Activity - Misplaced Pages Continue

1184-579: The person to vomit, defecate, and urinate. This phase is followed by twitching and jerking. Ultimately, the person becomes comatose and suffocates in a series of convulsive spasms . Common mnemonics for the symptomatology of organophosphate poisoning, including sarin, are the "killer Bs" of bronchorrhea and bronchospasm because they are the leading cause of death, and SLUDGE – salivation, lacrimation , urination, defecation, gastrointestinal distress, and emesis (vomiting). Death may follow in one to ten minutes after direct inhalation, but may also occur after

1221-502: The two precursors are stored separately in the same shell and mixed to form the agent immediately before or when the shell is in flight. This approach has the dual benefit of solving the stability issue and increasing the safety of sarin munitions. Sarin was discovered in 1938 in Wuppertal -Elberfeld in Germany by scientists at IG Farben who were attempting to create stronger pesticides; it

1258-715: The use of gases such as sarin as weapons. SLUDGE syndrome A cholinergic crisis is an over-stimulation at a neuromuscular junction due to an excess of acetylcholine (ACh), as a result of the inactivity of the AChE enzyme , which normally breaks down acetylcholine. As a result of cholinergic crisis, the muscles stop responding to the high synaptic levels of ACh, leading to flaccid paralysis , respiratory failure , and other signs and symptoms reminiscent of organophosphate poisoning . Other symptoms include increased sweating, salivation, bronchial secretions along with miosis (constricted pupils). This crisis may be masked by

1295-459: Was also planned to produce DC, but it was never constructed. A facility was planned to produce QL ( diisopropyl aminoethylmethyl phosphonite ), a precursor to the nerve agent VX . Construction began in the late 1980s, but it was mothballed prior to completion in the early 1990s as part of the chemical weapons treaties. Only partial construction of the Bigeye Bomb (BLU-80) fill and close facility at

1332-628: Was completed in 2002, and the Army began weapons disposal in March 2005. By May 2007, the facility had destroyed all of its GB (sarin)-containing rockets and began processing VX -containing munitions. In February 2008 they processed their last VX-containing rocket and in May 2008 began processing VX landmines. Landmine processing was completed in June 2008 and the facility changed over to processing ton containers of mustard gas ,

1369-504: Was used by the United States for the production of its unitary sarin stockpile. The scheme below shows a generic example that employs the Di-Di method as the final esterification step; in reality, the selection of reagents and reaction conditions dictate both product structure and yield. The choice of enantiomer of the mixed chloro fluoro intermediate displayed in the diagram is arbitrary, but

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