Phosphonofluoridic acid, methyl-, isopropyl ester
Isopropyl ester of methylphosphonofluoridic acid
O-Isopropyl Methylisopropoxfluorophosphine oxide
Methylfluorophosphonic acid, isopropyl ester
Sarin, a colorless and odorless gas, has a lethal dose of 0.5 milligram for an adult. It is 26 times more deadly than cyanide gas and is 20 times more lethal than potassium cyanide. Just 0.01 milligram per kilogram of body weight a pinprick sized droplet will kill a human. The vapor is slightly heavier than air, so it hovers close to the ground. Under wet and humid weather conditions
Sarin degrades swiftly, but as the temperature rises up to a certain point, sarin’s lethal duration increases, despite the humidity.
Mankind has always searched for more and more powerful weapons, whether it be a bigger rock to throw a better quality bow and arrow or musket or a more powerful bomb. Obviously this century it has been explosives of one kind or another. More specifically the
tendency has been for more powerful missiles or aerial bombs this race reached its height when the nuclear bomb was invented the power of these bombs were so
supremely powerful that the target would be of no use to anyone after the explosion due to the damage and contamination. So as a result the search for weapons that would kill the enemy but leave the surrounding area undamaged and any contamination short lived. Chemical and Biological weapons were the answer to these problems. Chemical weapons have been around in less sophisticated forms for decades, they were used quite extensively in the first world war but took the form of simple gasses such as chlorine and mustard gas. In this day and age the current crop of chemical weapons are far more dangerous and well researched.
Among the most dangerous chemical weapons are the so called nerve gasses or nerve agents, nerve agents have entirely dominated chemical warfare since the Second World War. Nerve agents acquired their name because they affect the transmission of nerve impulses in the nervous system. All nerve agents belong chemically to the group of organo-phosphorus compounds. They are stable and easily dispersed, highly toxic and have rapid effects both when absorbed through the skin and via respiration. Nerve agents can be manufactured by means of fairly simple chemical techniques. The raw materials are inexpensive and generally readily available. This makes them even more dangerous as they can be made by any irresponsible mind with a decent laboratory.
Chemical and Biological weaponry are the future of modern warfare. The governments of the world spend billions of pounds a year
researching more nerve gasses and biological weapons and cures for there effects. This pattern is not going to change but policing of this technology is going to
become increasingly important. Should the nations of the world ever have to fight someone other than
themselves Chemical and biological weapons will most likely be the most effective so
perhaps this research can be justified. It has always been mankind's nature to fight but it is important to consider that the American national military budget could solve the homeless problem in he states in Just over a year. Modern warfare does not require the amount of money that some countries spend on it but with human nature so
fickle another war is never going to be that far away.
History of nerve agents
A factory for production of this first nerve agent was built and a total of 12 000
tons of tabun were produced during the years three years (1942-1945). At the end of the second world war the Allies seized large quantities of this nerve agent and other nerve agents that Schrader and his co-workers has
synthesized. They synthesized about 2 000 new organo-phosphorus compounds, including
Sarin (1938). The third of the "classic" nerve agents, soman, was first produced in 1944. These three nerve agents are known as G agents in the American nomenclature. The manufacture of
Sarin never started properly and up to 1945 only about 0.5 tons of this nerve agent was produced in a pilot plant.
This was in hindsight a very good job or the history books would read very differently. Enough
Sarin gas could easily have won Germany the war. There is evidence that suggests that Hitler was advised against using the agents and even stopped their production. Hitler's Minister of Production, Albert Speer, said after the war, "All sensible army people turned gas warfare down as being utterly insane, since, in view of America's superiority in the air, it would not be long before it would bring the most terrible catastrophe upon German cities."
Immediately after the war, research was mainly concentrated on studies of the mechanisms of the nerve agents in order to discover more effective forms of protection against these new CW agents. The results of these efforts led, however, not only to better forms of protection but also to new types of agents closely related to the earlier ones. By the mid-1950's a group of more stable nerve agents had been developed, known as the V-agents in the American nomenclature. They are approximately ten-fold more poisonous than
Sarin and are thus among the most toxic substances ever synthesized never the less due to
Sarin's other properties it is still extremely effective
The first publication of these substances appeared in 1955. The authors, R. Ghosh and J.F.Newman, described one of the new strain of nerve agents substances, known as Amiton, as being particularly effective against mites. At this time, intensive research was being devoted to the organo-phosphorus insecticides both in Europe and in the United States. At least three chemical firms appear to have independently discovered the remarkable toxicity of these phosphorus compounds during the years 1952-53. Surprisingly enough, some of these substances were available on the market as pesticides. A remarkably stupid decision, they were soon withdrawn owing to their considerable toxicity to mammals and therefore humans this serves as a warning tat the proper research should be carried out before bringing out new product to spray over our food.
Another, more persistent agent, named VX was discovered by British chemist R. Ghosh. It was touted as being even more toxic than the previously synthesized nerve agents. Since the discovery of VX in 1949 there has been only minor advancements in the development of new nerve agents. In the United States, the choice fell in 1958 on a substance known by its code name VX as suitable as a chemical warfare agent of persistent type. Full-scale production of VX started in April 1961 but its structure was not published until 1972. Stockpiling the existing agents became a way for global heavyweights to flex their power in the later half of this century, but now efforts are being made to destroy the enormous stockpiles.
A famous contemporary use of nerve agents was in the Iran-Iraq war (1984-1988). In this conflict the UN confirmed that Iraq used the nerve agent Tabun and other
organophosphorus nerve agents against Iran. This incident is a prime example of how chemical warfare technology was shared during the Cold War. The Soviets would arm their allies while the US did the same for its allies. Iraq was obviously a benefactor and implemented its chemical stockpiles during the war. Another contemporary incident of nerve agent use occurred in Japan. The Aum Shinrikyo Cult was reported to have used the nerve agent Sarin in a Tokyo subway. This incident of use gives some clue as to the new roles that nerve agents play, as tools of terrorists instead of powerful nations.
The effective use of any chemical agent is dependent on its physical and chemical properties and on meteorological conditions.
(1) Persistency:- Chemical agents can be either persistent or non-persistent.
Non-persistent agents disperse rapidly after release and present an intermediate but short lived hazard. They are usually released as airborne particles.
Persistent agents continue to present a hazard for some quite considerably long time.
(2) Effectiveness:- Effectiveness is the capacity of an agent to produce the maximum number of casualties or amount of disruption
of operations with the least amount of agent, although other tactical criteria may be used to gauge this effectiveness. “Effectiveness” is a general term which takes in such criteria as suitability, toxicity, irritancy, etc. For instance, of two similar volatile toxic agents, the one which is toxic at a lower dose can be said to be more effective. Similarly, of two irritant compounds, the one which is irritant at a lower dose can be said to be the more effective. Effectiveness is also dependent on the ability of the population attacked to
neutralize or counter the effects of agents once they have been delivered. The duration of effectiveness depends on the physical characteristics of the agent, the amount of agent delivered, the weapon system used and the terrain and weather in the target area at the time the agent is delivered and later.
Nerve agents are organophosphorus esters. The “G’ agents tend to be non-persistent whereas the “V” agents are persistent. Sarin is a G-agent and is not as persistent as some of the more modern nerve agents. Although the new V-agents are so much more persistent than G-agents the more old fashioned nerve agents such as
Sarin are often more useful than the more persistent nerve agents it allows areas in which the nerve agents have been used to be populated quickly after the strike. Nerve gasses on the whole tend not to be gasses at all but a fine suspension of volatile liquids in air. This actually makes them just as effective as a gas but easier to store and to disperse making them a far better weapon.
Once produced, Sarin presents both a storage and delivery problem. In the 1950’s and 1960’s, military chemical weapons specialists conceived of the binary munitions concept to ameliorate these problems. Binary munitions contain two relatively non-toxic chemical components which are mixed during flight to their targets to produce standard nerve agents. The difference between
synthesizing a nerve agent and using it in the field is an extremely different prospect. Sarin is helpful as the last stage of its
synthesis can take place during delivery. The final stage is shown below.
Both of the reactants are fairly harmless and therefore ideal for a binary munitions , there is a concern that HCl is produced in the reaction but this adds to the effectiveness of the
weapon as long as the munition is not damaged pre explosion. This requires research and development of effective munitions, filling the munitions before use, and finding them a suitable delivery system. During the filling process itself, the agents must be transferred very carefully from storage vessels to the munitions, any spillage would result in premature mixing of the components producing the nerve agent ,a potentially fatal error. The munitions must be correctly sealed before
Special equipment and procedures to detect and locate leaks are needed both in the filling area and in the area where the munitions are
stored. This type of munition only has a limited shelf life and must be carefully
monitored. The picture shows the design of binary munitions for VX-gas but the design for
Sarin is very similar. These binary munitions can be fired using conventional artillery or more modern delivery systems.
Conventional artillery has a limited range and accuracy even if using modern robotic
artillery systems. Even a small shift in wind direction could result in sending a cloud of highly poisonous nerve gas back on the firer of the artillery.
As in the Iran Iraq war Scud missiles or any other Ballistic missiles can be used to deliver the nerve gas over vast distances protection from this sort of attack is limited to Patriot missiles which are fairly ineffective. This kind of delivery system is advisable as the nerve agent explodes a large distance away from the firer.
Land mines can be used to distribute the Sarin, this means is useful for smaller amount of the nerve gas. Its unusual as this delivery system is a triggered
system ideal for protection of a border or to cover retreat by making an area extremely dangerous to advance through. The disadvantages are that mines are
extremely difficult to remove and there is currently a worldwide campaign to reduce the use of landmines.
One of the more accurate long range delivery systems is the usage of cruise missiles. With modern design cruise missiles are
extremely accurate they can steer around building and other obstacles. they are extremely
difficult to shoot down due to there speed, Although some conventional cruise missiles were shot down by
small arms fire in Iraq but percentage wise a very small fraction. yet again the advantage of cruise missiles is that they have an exceptionally long range negating any risk to the firer.
Another long range delivery is aircraft bombing, with the new technology available aerial bombardment is know increasingly accurate. Modern
laser technology is however open to mistakes. The main disadvantage is that in order to deliver the bomb there is
a risk to the pilot or pilot of the plane but modern stealth technology will soon solve this problem. Given the nature of people power in modern politics rulers have to minimize the amount of people coming back home in boxes.
They new breed of rocket launchers as seen in the gulf known as MRLS systems they can fire large numbers of rockets with a medium range and
considerably accuracy these units are still extremely expensive and although they can fire significantly quicker than traditional artillery the expense may not be worth it as the technology is
unreliable and tends to have difficulty in extreme weather conditions.
Mortars can also be used in limited situation, they have limited range which can result in the clouds of
Sarin gas turning on the firer. Special training is required for troops who fire this type of warhead. This delivery system is often ineffective as the area under fire will be dangerous for sometime afterwards so the area cannot be occupied.
In summary Sarin is very versatile as a weapon it can used in most arenas and can be delivered by a large range of methods depending on the situation and the amount required.
Chemical agents may enter the body by several routes and the nature and onset of signs and symptoms may vary accordingly. Gases,
vapors and aerosols, when inhaled, may be absorbed through any part of the respiratory tract, from the mucosa of the nose and mouth to the alveoli of the lungs. They may also be directly absorbed by the eye. Aerosol particles larger than 5 µm tend to be retained in the upper respiratory tract, while those smaller than 1 µm tend to be breathed in and out again, although some of these smaller particles may be retained. Droplets of liquid and, less commonly, solid particles may be absorbed through the surface of the skin and mucous membranes. Toxic compounds with a characteristic action on the skin can produce their effects when deposited on the skin as solid or liquid particles. Agents which penetrate the skin may form temporary reservoirs so that delayed absorption may occur. Even the
vapor of some volatile agents can penetrate the intact skin and intoxication may follow. Wounds or abrasions (even minor injuries caused by shaving ) present areas which are more permeable than intact skin. Chemical agents may contaminate food and drink and so be absorbed by the gastrointestinal tract. The penetration of agents through the gastrointestinal tract or abrasions may not
necessarily be accompanied by irritation or damage to the surfaces concerned.
A full list of symptoms of Sarin nerve agent are listed in a table in the appendix table 2
The effects of organophosphate nerve agents in general are mainly due to their ability to inhibit acetyl-cholinesterase throughout the body. Since the normal function of this enzyme is to
hydrolyze acetylcholine wherever it is released, such inhibition results in the accumulation of excessive concentrations of acetylcholine in The nerve endings of the body . These sites include the endings of the parasympathetic nerves to the smooth muscle of the iris, ciliary body, bronchial tree, gastrointestinal tract, bladder and blood vessels; to the salivary glands and secretory glands of the gastrointestinal tract and respiratory tract; and to the cardiac muscle and endings of sympathetic nerves to the sweat glands. The accumulation of acetylcholine at these sites results in characteristic muscarinic signs (Emptying of bowels and bladder , Blurring of vision, profuse
sweating, profuse salivation and stimulation of smooth muscles. The accumulation of acetylcholine at the endings of motor nerves to voluntary muscles and eventually
in paralysis. The accumulation of excessive acetylcholine in the brain and spinal cord results in characteristic central nervous system symptoms which are
tabulalated in the appendix table 1.
The following diagram shows the normal path by which acetylcholine is hydrolyzed
in the body by acetyl-cholinesterase it is this process that Sarin interrupts
The choline is taken up by the pre-synaptic or pre-junctional nerve terminals and recycled by combination with acetyl Cholinesterase
catalyzed by the enzyme choline acetyltransferase to form more acetylcholine. The destruction of acetylcholine by acetylcholesterase is a very rapid reaction. The inhibition of cholinesterase enzymes throughout the body by nerve agents may be irreversible and its effects
prolonged as a result treatment with oximes should begin promptly if there is to be any chance of survival. Until the cholinesterase enzymes are restored to normal activity, the subject is
extremely sensitive to the effects of any other nerve agent. The period of increased sensitivity occurs during the enzyme regeneration phase which could last from weeks to months, depending on the severity of the initial exposure. During this period the effects of repeated exposures are cumulative.
Acetylcholinesterase is found associated with the post-junctional membrane at the neuromuscular junction and in the cell bodies and processes of cholinergic neurons. The concentration is particularly high in some central nervous system neurons. The location of acetylcholinesterase in autonomic ganglia is less well understood than that at the neuromuscular junction. Acetylcholinesterase is also found at sites where, as yet, no functional role has been identified: the musculotendinous junction, red blood cells, platelets and the placenta. The diagram below shows the mechanism of action for
Sarin nerve agent. It works by bonding directly to the enzyme preventing
Cause of death
In the absence of treatment, death is caused by anoxia resulting from airway obstruction, weakness of the muscles of respiration and central depression of respiration.
Airway obstruction is due to pharyngeal muscular collapse, upper airway and bronchial secretions, bronchial constriction and occasionally laryngospasm and paralysis of the respiratory muscles.
Respiration is shallow, labored, and rapid and the casualty may gasp and struggle for air. Cyanosis increases. Finally, respiration becomes slow and then ceases.
Unconsciousness ensues. The blood pressure (which may have been transitorily elevated) falls. Cardiac rhythm may become irregular and death may ensue.
If assisted ventilation is initiated via cricothyroidotomy or endotracheal tube and airway secretions are removed by postural drainage and suction and diminished by the administration of atropine, the individual may survive several lethal doses of a nerve agent. However, if the exposure has been overwhelming, amounting to many times the lethal dose, death may occur despite treatment as a result of respiratory arrest and cardiac arrhythmia.
When overwhelming doses of the agent are absorbed quickly, death occurs rapidly without orderly progression of symptoms.
Sarin: A terrorist weapon
The Buddhist sect was founded in 1987 by Chizuo Matsumoto, alias Shoko Asahara. The group has its headquarters in central Japan with 19 branches throughout the country. The doctrines of Aum Shinrikyo are based on ancient yoga and primitive Buddhism, and require worshipping the Hindu God Siva, believed to preside over both destruction and creation. Destruction has been elevated by the cult and is viewed as on par with creation. The sect has tried to build its own "kingdom" within its controlled compound facilities by establishing ministries and agencies under Asahara, its paramount leader. Among these, the sect "Science and Technology Agency" consists of scientists who graduated from prestigious universities in Japan. It is divided into several teams specialized in chemistry, biology, physics and medicine. This
organization provided the technical information required to synthesize the Sarin.
On the day of the disaster, 641 victims were seen at St. Luke's International Hospital. Among those, five victims arrived with cardiopulmonary or respiratory arrest with marked miosis and extremely low serum cholinesterase values; two died and three recovered completely. In addition to these five critical patients, 106 patients, including four pregnant women, were hospitalized with symptoms of mild to moderate exposure. Other victims had only mild symptoms and were released after 6 hours of observation. Major signs and symptoms in victims were miosis, headache, dyspnea, nausea, ocular pain, blurred vision, vomiting, coughing, muscle weakness, and agitation. Almost all patients showed miosis and related symptoms such as
headache, blurred vision, or visual darkness. Although these physical signs and symptoms disappeared within a few weeks,
psychological problems associated with posttraumatic stress disorder persisted longer. Also, secondary contamination of the house staff occurred, with some sort of physical abnormality in more than 20%.ON MARCH 20, 1995, terrorists released
Sarin, an organophosphate nerve gas at several points in the Tokyo subway system, killing 11 and injuring more than 5,500 people.
This was the second Sarin gas incident involving civilians after the first Matsumoto
Sarin incident in which the same terrorist group killed seven and injured more than 200 people.
On the day of the Sarin release, 641 patients were seen at St. Luke’s International Hospital and 349 were seen in the following week .
Thus, the Japanese authorities treated the largest reported patient population exposed to
The nerve gas Sarin was released in commuter trains on three different Tokyo subway lines by a terrorist cult group. Sarin was concealed in lunch boxes and soft-drink containers and placed on subway train floors. It was released as terrorists punctured the containers with umbrellas before leaving the trains. The incident was timed to coincide with rush hour, when trains were packed with commuters. Over 5,500 were injured in the attack. A subway station close to St. Luke’s International Hospital was one of several sites hit simultaneously in the attack; therefore, many of the victims were sent to St. Luke’s International Hospital. In hindsight the manner in which the
Sarin was dispersed was incredibly ineffective but even from this ineffective method the death and injuries were considerable. If a more effective means of dispersion has been
utilized in such an enclosed area there would have been thousands dead.
Of the 641 patients seen at St. Luke’s International Hospital on the day of the disaster, five were in critical condition. Three patients had cardiopulmonary arrest and two were unconscious and had respiratory arrest soon after arrival. Of these five critically ill patients, three were successfully resuscitated and able to leave on hospital day 6. One of
the patient who had cardiopulmonary arrest did not respond to cardiopulmonary resuscitation (CPR) and died with findings of very
bizarre miosis (gamete production) that continued even at the time of her death. A second patient with cardiopulmonary arrest was resuscitated but died on hospital day 28 due to irreversible brain damage. This patient had markedly decreased serum ChE level of a fiftieth of there normal levels rendering the patient
completely unable to send nerve pulses around the body. The third cardiopulmonary arrest patient, a 21- year-old woman who collapsed while attempting to leave the subway was fed a cocktail of drugs for 10 days until she recovered her serum ChE level was
extremely low but recovered to near normal levels after several weeks. The fourth and fifth critical patients were drowsy when brought to the emergency center; several minutes later, both had convulsions and lapsed into respiratory arrest.
Intravenous diazepam injections and mechanical ventilation improved neurological
status and they were soon able to breath on there own. The fourth patient was discharged on day 3 and the fifth on day 4. Initial treatment for these critically ill patients included CPR, 2 mg of intravenous atropine sulfate, and 5 mg to 20 mg of intravenous diazepam for convulsive disorders. After learning that
Sarin gas was responsible for the patients’ symptoms, intravenous pralidoxime iodide was added to this regimen. In view of the patients’ peculiar signs of miosis and markedly decreased serum ChE levels, an
organophosphate compound was suspected to be the causative agent and PAM was initiated in two cases before
Sarin was identified as the causative agent.
The important thing to remember about the Japanese incident is that it was a let off, a warning. There is the potential for a far more serious
incident, as a second year chemical student there is no great difficulty involved in the synthesis. The raw materials are reasonably easy to get hold of. Having said this only a small amount is required if the dispersal
method is efficient. In this incident the dispersal was very poor, which saved many lives. Unfortunately when terrorists get hold of weapons such as this
they have no government or subjects to answer to allowing them to be as irresponsible as they like. For these reasons the supply of the raw materials must be more tightly
controlled. Even though the raw materials can be kept in the same containers as other
legitimate chemicals all that is required is a rigorous testing procedure.
Protection Against Chemical Weapons
There are four main cornerstones in the protection against chemical weapons, all of which are largely dependent upon each other to provide optimum effect. These four are:
- physical protection: body protection, respiratory protection, collective protection,
- medical protection: pretreatment, therapy ,
- detection: alarm, monitoring, verification, identification, all-clear,
- decontamination: individual decontamination, equipment decontamination.
Physical protection consists of body protection, respiratory protection , medical protection and early warning. Medical protection must take the form of pre-treatment with drugs to
minimize the effects of the nerve gasses. This has been problematic in the past, there were severe effects on many soldiers after the gulf war. None of this is at all useful unless soldiers are trained and if precise information can be obtained for this reason detection ,alarms, monitoring, verification, identification can all be just as important as gas masks and drugs.
Training in how to behave in war environment when nerve gasses such as Sarin are going to be used and how Chemical warfare protective equipment is used is essential, not least to give the soldiers confidence in their equipment. Even though the soldiers are trained and have access to the best possible protective equipment, there will be a decrease in their performance once they have started to use the protective equipment. This is particularly noticeable in hot weather. Impermeable CW protective suits and also to some extent permeable suits which "respire" are very hot. During hard physical work, the surplus energy cannot be removed and therefore the soldier will rapidly become overheated and may suffer from heat collapse this was especially common in the gulf war. This implies a major complication for chemical warfare protection during the summer, particularly in very hot areas such as desert. Protective equipment is relatively clumsy, which implies that most tasks require longer to perform than normal. Endurance decreases and when a protective mask is worn, it becomes difficult to communicate with people in the
neighborhood. In tactical behavior, contamination avoidance is essential. There may be a long delay until decontamination can be done so that the protective clothing can be removed. In addition, decontamination is time consuming. Subsequently, the permeable suits must be destroyed and new equipment made available. All of this means practical protection from nerve agents is impractical.
The best way to handle chemical protection is to discourage an aggressor from using nerve agents in the first place. In military terms this implies taking measures so that an aggressor cannot attain major military advantages. As with nuclear weapons stockpiling is often the best
defense .In modern warfare the idea is to bomb the factories and missile sites to prevent the enemy from being able to fire any chemical weapons in the first place. In modern times there are missiles capable of destroying missiles in mid flight, such as the patriot missiles used in the Gulf war although these will never be one hundred percent efficient they can be the best option. Depending on the purpose of different protective measures, they are divided into two categories according to the US State Department. The first category is called the basic protection. In individual basic protection, which aims at increasing the individual's opportunities to survive, there are a protective mask, protective all-enveloping clothing, boots and gloves, as well as individual decontamination kit and medical antidotes. The basic protection associated with military units includes measures for the unit to be able to evaluate the situation when
Sarin or other chemical weapons have been used, to detect and decontaminate as well as to rescue and provide care. The second category is mission specific protection. This implies measures for important units, such as the background staff which keep the troops
organized or secret services such as the SAS can carry out tasks so that they can continue to work with their primary tasks to the greatest possible extent. The aim is that the
defense forces will retain their operative ability even after Sarin attacks. Mission specific protection is adapted to the mission and thus varies between different systems and functions. This may, for example, concern collective protection in tanks and fortifications or permeable Chemical warfare combat suits for turn around and repairs at an air base.
For civil rescue units such as police fire services and medical services, and also for other personnel in the civil
defense with active outdoor duties, the same demands on protective equipment apply as for personnel in the armed forces. The civil
defense sector would be vital in any Sarin attack. However, in the case of the civilian population, the only realistic option is early warning followed by shelters. Consequently, the protective equipment does not need to be as advanced as corresponding equipment for personnel with direct outdoor duties. This is the reason why it is possible to use a civilian protective mask of a simpler design, a recent example was the simple gas masks given out to Israeli citizens during the Gulf War.
For younger children, a protective jacket can be used instead of a protective mask. Such a jacket protects the respiratory organs and also gives some protection against
Sarin agents in liquid form. A battery powered fan forces air through a filter and the purified air flows in front of the child's face. Children younger than about 12 months can be given a protective "carry-cot". Slightly older children, but still too small to accept a protective jacket or a protective mask should be given some kind of collective protection. Collective protection for civilians can be made available in shelters with filters which absorb the nerve agents.
A warning system for nerve agent attacks can consist both of sirens in urban areas and of warnings on the radio and television. The police and army could equip special patrols for detection and relief in environments contaminated with
Sarin agents. The civil defense can also have the responsibility for informing the general public when it is risk-free to leave shelters, to air their homes etc.
In protection against chemical warfare agents the decontamination is an important
unavoidable part. The aim of decontamination is to rapidly and effectively render harmless or remove poisonous substances both on personnel and equipment. High decontamination capacity is one of the factors which may reduce the effect of an attack with Sarin gas. In this way, it may act as a deterrent.
Equipment can be covered, or easily decontaminated equipment can be chosen by suitable design and a more resistant surface cover.
Decontamination is time consuming and requires resources. Nerve agents are easily soluble in, and penetrate many different types of material, such as paint, plastics and rubber, all of which renders decontamination more difficult. If nerve agents have penetrated sufficiently deep, then toxic gases can be released from the material for long periods afterwards. By adding substances which increase the viscosity of a
Sarin, its persistence time and adhesive ability can be increased. This thickened
Sarin will therefore be more difficult to decontaminate with liquid decontaminants since they adhere to the material and are difficult to dissolve.
All decontamination is based on one or more of the following principles:
- to destroy CW agents by chemically modifying them (destruction),
- to physically remove CW agents by absorption, washing or evaporation,
- to physically screen-off the CW agent so that it causes no damage.
Most nerve agents can be destroyed by means of suitable chemicals. Some chemicals are effective against practically all types of substances. However, such chemicals may be unsuitable for use in certain conditions since they corrode, etch or erode the surface. Sodium hydroxide dissolved in organic solvent breaks down most substances but should not be used in decontaminating skin other than in extreme emergencies when alternative means are not available.
Sarin and other G agents are rapidly hydrolyzed in basic solutions, e.g., Na2CO3, NaOH, or KOH; GB has a half-life of 0.5 minutes at pH 11 at 25°C Catalysts for Sarin hydrolysis include hypochlorite anion (OCl-), several metal ions and their complexes (Cu+2, UO2+2, ZrO+2, MoO2+2, Th+4 ) and iodosbenzoic acid derivatives Current decontamination systems based on this chemistry include
solids, powders and solutions containing various types of bleach (NaOCl- or Ca(OCl-))
DS2 (2% NaOH, 70% diethylenetriamine, 28% ethylene glycol monomethyl ether) towelettes moistened with NaOH dissolved in water, phenol, ethanol, and ammonia.
The most important decontamination measure naturally concerns the individual. If it is suspected that skin has been exposed to liquid
Sarin, then it must be decontaminated immediately (within a minute). All experience confirms that the most important factor is time; the means used in decontamination are of minor importance. Good results can be obtained with such widely differing means as talcum powder, flour, soap and water, or special
decontaminants. In complete decontamination, clothes and personal equipment must also be decontaminated. If clothes have been exposed to liquid contamination, then extreme care must be taken when undressing to avoid transferring
Sarin to the skin. There may be particular problems when caring for injured since it may be necessary to remove their clothes by cutting them off. This must be done in such
a way that the patient is not further injured through skin contact with CW agents. During subsequent treatment it is essential to ensure that the entire patient is decontaminated to avoid the risk of exposing the medical staff to the
Sarin. In most countries, a soldier's equipment includes means for individual decontamination, generally a mixture of chlorinated lime and magnesium oxide. This decontaminant works by absorbing liquid substances and also by releasing free chlorine which has a destructive effect on organophosphate agents.
The dry powder also has good effect on thickened agents since it bakes together the sticky substance which makes it easier to remove. Personal decontaminants containing chlorinated lime have, however, an
irritating effect on the skin. Consequently, comprehensive use should be followed by a bath or shower within a few
hours. Liquid personal decontaminants are common in some countries. Sodium phenolate or sodium cresolate in alcohol solution are used for individual decontamination of nerve agents. Chloramines in alcohol solution, possibly with additional substances, are commonly used against, e.g., mustard agent. Instead of liquid individual decontaminants, it is possible to use an absorbent powder such as bentonite ("Fuller's Earth"). In the U.S.A. the wet method formerly used was replaced by a decontaminant powder based on a mixture of resins, which decompose CW agents, and an
absorbent. A factor common to all individual decontaminants is that they can effectively remove
Sarin on the surface of the skin. However, they have only limited ability to remove
Sarin which have become absorbed by the skin, even though very superficially. Sarin
agents that have penetrated into the skin therefore function as a reservoir which may further contribute to the poisoning also after completed
decontamination. In some cases, a wet method may give a better result in decontaminating deeply penetrated agents than a dry method. Reports from France indicate that a solution of potassium permanganate gives effective destruction of CW agents on the surface of the skin and also a certain penetrating effect. There are also individual decontaminants which can simultaneously function as a protective cream for use as a prophylactic. Canada has developed a mixture of a reactive substance (potassium 2,3-butadion monoximate) in polyehylenglycol, which has both these properties. It can be applied to the skin either as a cream or with a moist tissue.
The enzyme that Sarin inhibits, normally breaks down acetylcholine into
acetic acid and choline.
A fine suspension of liquid particles in air.
One of the second generation nerve agents similar to VX-gas 10 times more toxic than Sarin.
The name of the Japanese cult responsible for the Sarin bombing.
A two part shell which allows the two chemicals necessary in the final stage of Sarin
synthesis allows the reaction to occur shortly before explosion.
One of the names by which the head of the Japanese cult responsible for the Tokyo
One of the products from the hydrolysis of acetylcholine (see effect page for structure).
The American name for the first three nerve agents Sarin, Tabun and soman.
Alternative name for Sarin gas.
An Organic compound containing a Phosphorus Oxygen double bond.
Scientific name for the reproduction of gametes.
The American name for mobile mass missile launcher like the ones used in the gulf.
One of the names by which the head of the Japanese cult responsible for the Tokyo bombing.
One of the first generation of organophosphate nerve agents.
The first purpose made nerve agent.
Second generation post second world war nerve agents includes VX-gas. They are all
organophosphates significantly more potent than Sarin and the first generation nerve gasses.
One of the V-agents (discovered in 1949)far more persistent than the first generation