CBRNe incidents caused by attacks or accidents with chemical agents are characterized by an immediate effect on the people and elements affected and by a short reaction time for the First Response teams in order to mitigate the effects of the same.
CBRN protocols establish a clear differentiation between two types of chemical agents: the Chemical Warfare Agents (CWA) and the Toxic Industrial Chemical (TIC).
CBRN protocols about CBRNe incident management in general and about CBRN Decontamination in particularly, also make a differentiation among both of them: as TICs are usually associated with CBRNe incidents generate by accidents in the industry environment (either in manufacturing plants or in hazmat transportation). Thus some of the most serious and devastating CBRNe incidents in history have been accidents with TICs agents:
- Bhopal accident (India) in 1984 (pesticide factory accident that caused more than 15,000 deaths and more than 600,000 affected).
- Accident of Oppau (Germany) in 1921 (factory crash of Ammonium Nitrate that caused more than 500 deaths and more than 2,000 injured).
- Accident in Toulouse (France) in 2001, accident at the fertilizer plant that caused 29 deaths and more than 2,500 injured).
- Accident of Texas City (USA) in 1947 (accident on a ship carrying ammonium nitrate that caused the death of 576 people and the destruction of more than 1,000 buildings).
For its part, chemical warfare agents (CWAs) are related to NBC incidents caused by war actions or terrorist attacks, although it is true that in recent years the use, in some terrorist attacks, of ICT agents has increased. Since they are easier and cheaper agents to acquire, manipulate or manufacture than CWAs.
Generally chemical warfare agents (CWAs) are classified into 5 main categories: Incapacitating agents, Nerve agents, Blood agents, Blister agents and Choking agents.
1. Incapacitating Agents
Disabling agents are all those substances that cause temporary mental or physical disability. Over the years, attempts have been made to classify incapacitating agents from a military point of view in different ways. Currently, the key distinction lies in the duration of the disability, so that two classes of agents can be distinguished: Neutralizers and Calming agents.
1.1 Neutralizers
The chemicals that cause disability for some time longer than the exposure, as is the case of most of the irritants used by the police to control riot. This group is known as neutralizers, irritants or harassing agents. They produce irritation mainly in the eyes and respiratory system. The most used militarily are Lachrymatory agent CN and CS.
Lachrymatory agent CN
Description: CN or 2-chlororacetophenone is a white crystalline solid with an odor similar to the flowers of the apple tree. It was developed at the end of the First World War. It is intensely irritating to the eyes, the mucous membranes of the nose and the upper respiratory tract. CN can give rise to hydrogen chloride by thermal decomposition. It is widely available commercially as riot control agent or personal protection mechanism
Exposure: By inhalation or by contact with skin and eyes
Symptoms: It can cause two effects: it usually produces irritant dermatitis, but it can also cause edema. Exposure to CN in aerosol form causes symptoms that develop in two stages: first, redness and burning sensation in the eyes and face, and the next day, an edema (secretion of fluid inside the cellular tissues) with swelling of the eyelids. The secretion quickly forms scabs and, if treatment is not administered, infection can occur. Healing requires up to 10 to 15 days of treatment. Repeated exposures can cause allergic reactions. Pulmonary lesions only occur in cases where CN has been used in very small spaces, and the symptoms take a few days to appear. The normal thing is the appearance of pulmonary edema and bronchospasm, and can even lead to the death of the affected person.
Treatment: The eye should be washed with a weak solution of boric acid. Contaminated skin should be washed with a sodium carbonate solution or with plenty of soap and water. Then you can use soothing solutions such as calamine on injured skin.
Stability / Persistence: Little persistent. In the soil the permanence is probably moderate to high, although not enough data is available to make a real prediction. In water it can be decomposed by photolysis. Reacts with hydroxyl radicals produced photochemically and has a half-life of 9.2 days in the vapor phase.
Decontamination: to perform the decontamination of surfaces contaminated by Lachrymatory agent CN (especially the skin, eyes, mucous membranes, etc). The eyes and face should be washed immediately with plenty of water. Most soaps contain oily substances so they should not be used to wash the area since this substance traps the agent on the skin and can cause a rash or severe burn. The affected clothes must be changed.
Lachrymatory agent CS
Description: In its pure form, the CS or 2-chlorobenzalmalononitrile is a white, crystalline powder, which resembles talc and whose odor is somewhat pungent. As it consists of solid particles, it must be dispersed in the air, mixed with another agent or in fine powder form. It was prepared for the first time in 1928, however it was not until 1956 that it was developed and applied as a riot control agent. In 1960, the CS was officially adopted by the United States Army as an anti-riot agent. By thermal decomposition it can give rise to phosgene or hydrogen chloride.
Exposure: Via inhalation or by contact with skin or eyes.
Symptoms: Ocular and respiratory tract symptoms occur very rapidly at concentrations of 4 mg / m3. The first symptoms that appear are burning eyes, tearing, rhinorrhea, salivation, blepharospasm, injection of the conjunctiva, sneezing and cough that develop rapidly to levels of harassment. Exposed skin, particularly in moist areas, begins to burn and burn after a few minutes, followed by the appearance of an erythema. Some individuals may feel nausea and vomiting. When CS is disseminated in a transporting solvent, exposure to the latter can further complicate the clinical picture, so that irritation of the eyes and skin will be more persistent. At high concentrations, the reactive airway dysfunction syndrome (RADS) can occur.
Treatment: Treatment will depend on the route of exposure. If it is dispersed like a fine powder, it is preferable to keep it dry and remove it from the individual by blowing as much as possible with the use of a hair dryer. When the administration is in spray with a solvent it is recommended to irrigate the affected areas with warm water, for at least 15 minutes. Any particles deposited in the eyes after evaporation of the solvent should be washed with copious amounts of warm water. Brief contact with water hydrolyzes CS and may aggravate burn symptoms. Water and soap can be used to wash the skin, but it must be followed by irrigation with warm water for 15 minutes. CS dissolves rapidly in a solution of sodium metabisulfite and such solutions can be used to remove solid particles from the irritant. Saline or weak solutions of boric acid can relieve eye symptoms and soothing lotions such as calamine can be used on injured skin. Wet dressings that allow evaporation can soothe the skin, and should be changed every 2 to 3 hours. Any skin infection should be treated with antibiotics
Stability / Persistence: Little persistent. There are formulations of CS that increase their permanence in the environment. Two hydrophobic and anti-agglomerative powder formulations, CS1 and CS2, respectively, have been developed. CS1 contains a 5% hydrophobic silica airgel and persists for about 2 weeks under normal weather conditions. CS2, a siliconized form of CS1, has greater weather resistance and can remain active for up to 48 days. Due to their persistence, it is possible that these two forms of CS are used in an exclusively military context. CS dust, used as riot control, and dust derived from it can settle on the ground and remain active for 5 days. Sometimes the permanence of traces of CS exceeds 5 days.
Decontamination: The decontamination of surfaces contaminated by Lachrymatory agent CS (either surfaces of the human body or other types of materials) presents a serious problem. Since the disseminated particles adhere to the person, clothes, furniture or equipment for long periods. Wet conditions will cause the odor and irritant to last indefinitely. Decontamination is achieved using an alkaline solution. Normally a solution of water and 5% sodium bisulfite is used for this purpose.
1.2 Calming agents
Those chemical products that cause disability for a period significantly longer than the exposure. This group is commonly referred to as incapacitating or soothing, the latter term being the one that is currently being used. In both categories, the time of onset of disability is also an important determinant of its usefulness.
Well known Calming Agent is 3-quinuclidinyl Benzilate (BZ), an anticholinergic agent whose psychic and physiological effects can persist for days.
Benzilate BZ
Description: BZ is the hydrochloride salt of 3-quinuclidinyl benzilate. It is an anticholinergic compound structurally and pharmacologically similar to Atropine, which affects both the Peripheral Autonomous System and the Central Nervous System. The difference with respect to atropine is that it is 100 times more potent. 3-Quinuclidinyl benzilate is commercially produced as an intermediate product of the drug clidinium bromide.
Exposure: Inhalation is the most likely route, but other possible routes are intravenous, intramuscular and oral. As an aerosol, particles that range from 0.6 to 0.8 μm are more effective than larger particles. Cumulative effects may occur after repeated exposures.
Symptoms: The symptoms, which appear quickly and last for more than 90 hours, consist of increased heart rate and blood pressure, dry skin and mouth, mydriasis, blurred vision, ataxia, disorientation and confusion. At low concentrations, individuals become slower to react, less alert and more sleepy. As the dose increases, the symptoms intensify, deteriorating motor coordination, increasing confusion, apprehension and restlessness, so that contact with reality is lost
Treatment: In cases of mild or moderate poisoning only a close watch should be made, lower the body temperature and wait 24-48 hours for the metabolic elimination of the drug. In more severe cases, parasympathomimetic agents such as anticholinesterase should be administered. Physostigmine is administered intravenously, so that it crosses the blood-brain barrier more easily and suppresses hallucinations, excitation and coma. If there are seizures, it may be convenient to administer Diazepam intravenously.
Stability / Persistence: It is very persistent, the appearance of symptoms occurs at approximately 4 hours. Hydrolysis of BZ solutions depends on time and pH. Increasing the pH increases the hydrolysis rate. An alkaline pH> 13, which is obtained with 5% solutions of sodium hydroxide, causes rapid hydrolysis. It is likely that the BZ will remain in the environment for some time. There is no data available on their average life on the ground.
Decontamination: to decontaminate surfaces contaminated by the BZ agent (whether from the human body or other materials), CBRN decontamination protocols usually define the use of detergent substances that wash contaminated surfaces and that are dispersed in the form of spray or shower over individuals or contaminated equipment
2. Nerve Agents
They are organophosphorus substances that act in the Central Nervous System blocking the action of Acetylcholinesterase, the enzyme responsible for the nervous impulse. Under normal conditions they are colorless liquids and their potential as a weapon is based on the phosphorus atom, whose bonds are easily hydrolyzed by compounds such as water or alkali ions.
There are two main families of nerve agents that are used primarily for military purposes, the G series, which are alkyl esters of methylphosphonofluoride acid or dialkylphosphoramididocyanidic acid, and the V series, which are primarily alkyl esters of S-dialkylaminoethylmethylphosphonothiol acid. The G-series agents are designed to act by inhalation, while the V agents act primarily through the skin and inhale aerosols. The nervous agents when they are released into the air, are degraded by the substances that are in the air, and may persist for a few days. In water and moist soil they are quickly hydrolyzed and only small amounts will evaporate. Through the ground they can contaminate groundwater but never accumulate in the chain
2.1 Nerve agents G Series
German scientists were the first to synthesize the agents of this series, the first was the Tabún (1936) then discovered the Sarin (1938), followed by Somán (1944) and finally the Cyclosarin (1949). The symptoms that reveal their action are: small pupils, extreme headache, severe chest tightness, dyspnea, rhinorrhea, cough, salivation and insensibility.
All nerve agents in the G series share a large number of physical and chemical properties. At room temperature, they are volatile liquids, assuming a serious risk by inhalation or contact. Sarin is the most volatile and evaporates at the same frequency as water, and Somán is the second most volatile agent.
The vapors of these agents are denser than air, making them particularly dangerous in low areas. They are soluble in water and fat, so they are quickly absorbed through the eyes, respiratory tract and skin.
Tabun (GA)
Description: Tabun or ethyl dimethylamino-cyanophosphate is not found naturally in the environment. It is a clear, colorless and tasteless liquid that has a slight smell of fruits. Currently it is considered ineffective and is rarely used as an agent of war. It is cheap and easy to produce. Tabún decomposes slowly in the body, which means that repeated exposures to Tabún or other nervous agents can have a cumulative effect.
Exposure: Exposure to Tabun in the form of vapor or aerosol can be through contact with skin and eyes or through inhalation of vapors. Tabun dissolves easily in water, so it can be used to contaminate water and food, so exposure by ingestion is also possible. The lethal dose by inhalation is 400 LCt50 and per contact is 1000 LD50.
Symptoms: vary depending on the amount of agent you are exposed to. At a weak exposure of the Tabun, in the vapor phase, the symptoms appear after a few minutes and are miosis, rhinorrhea and respiratory distress. At high levels consciousness is suddenly lost, convulsions, apnea, nausea, flaccid paralysis and abundant secretions occur. Symptoms due to moderate exposure of Tabun in liquid form in the skin appear from the first minutes until 18 hours after exposure and cause localized sweating, nausea, vomiting, weakness. Continued exposure to this gas, either in the vapor phase or in the liquid phase, generates sudden loss of consciousness, seizures, apnea, flaccid paralysis and abundant secretions.
Treatment: Atropine and Pralidoxime Chloride are used, which displace the action of the nerve gas. In severe cases, you must administer Diazepam (anticonvulsant), ventilation and aspiration through the respiratory tract.
Stability / Persistence: It is a highly volatile gas.
Decontamination: to decontaminate surfaces contaminated by Tabún (GA) (whether on surfaces of materials and vehicles or on the human body), CBRN decontamination protocols generally define their neutralization by dissolving in water or neutral pH media , this reaction is accelerated by Alkali Ions, transforming the tabun into phosphoric acid, which is not toxic. In this decontamination process, hypochlorite and large amounts of water are usually used.
Sarin (GB)
Description: Sarin or O-isopropyl methylphosphonofluoridate was originally developed as a pesticide in 1938. It is a clear, colorless and tasteless liquid that has no odor in its pure form. It can volatilize and spread to the environment.
Exposure: By inhalation or by contact with skin and eyes. The lethal dose by inhalation is 100 LCt50 and per contact is 1700 LD50.
Symptoms: Symptoms occur in a matter of seconds after exposure to the agent in the form of vapor and within minutes or up to 18 hours after exposure to the liquid form. A single drop of this agent in liquid form can cause sweating and muscle contraction of the affected area. The symptoms that appear before an exposure to this type of nervous agent are the same as for Tabún. In mild or moderate doses headache, mucus, excess salivation, indicative pupils, difficulty in breathing, chest pressure and seizures occur. People who have been mildly or moderately exposed usually recover completely. However, exposure to high doses can cause loss of consciousness, seizures, paralysis and respiratory failure that can lead in most cases to the death of the affected person.
Treatment: First step is to remove Sarin from the body as soon as possible and provide supportive medical care in a hospital setting. Subsequently, the treatment consists of the rapid administration of reversible anticholinestera agents, that is, anticholinergic and anticonvulsant agents such as Atropine and Diazepam.
Stability / Persistence: It is the most volatile nerve agent because it can quickly pass from liquid to vapor. In this way, people can be exposed to steam without having come into contact with the liquid form of Sarin. Due to its rapid evaporation, it poses an immediate but short-term threat.
Decontamination: to decontaminate surfaces contaminated by Sarin (GB) (whether on surfaces of materials and vehicles or on the human body), CBRN decontamination protocols generally define their neutralization by rapid and thorough washing of the skin with water and a dermogel (specific decontamination agents for use on people). This washing should be done for a period of 5 -10 minutes. In the case of decontamination of materials contaminated by Sarin gas (GB), large quantities of water and alkaline media (decontaminating agents) are used.
Soman (GD)
Description: Somán or O-1,2,2-trimethylpropyl methylphosphonofluoridate is a clear, colorless and tasteless liquid that has a mild smell of camphor or rotten fruit. It was originally developed as an insecticide by the Germans in 1944.
Exposure: If the release of Somán occurs in the air, people may be exposed through contact with skin and eyes or by inhalation of vapors. It is a compound that dissolves easily in water so it can be used to contaminate water and food. The lethal dose by inhalation is 70 LCt50 and by contact is 50 LD50.
Symptoms: Symptoms occur within seconds after exposure to the agent in the form of vapor and within minutes or 18 hours after exposure to the liquid form. A single drop of this agent in liquid form can cause sweating and muscle contraction of the affected area. The symptoms that appear when exposed to this type of nervous agent are the same as for tabun. People who have been exposed to low or moderate doses of soman by inhalation, ingestion, or skin contact may experience any or all of the following symptoms within a few seconds to hours after exposure: runny nose, watery eyes, small pupils, pain in the eyes, blurred vision, salivation and excessive sweating, cough, chest pressure. People who have been mildly or moderately exposed usually recover completely. Exposure to high doses of Somán can cause loss of consciousness, seizures, paralysis and respiratory failure that can lead in most cases to the death of the affected person.
Treatment: The first step is to remove the Somán from the body as soon as possible and offer medical support in a hospital setting. Subsequently, the treatment consists in the rapid administration of Atropine and Diazepam.
Stability / Persistence: Soman agent n is a very volatile agent, so it presents an immediate but short-term threat, not staying for long in the environment. Clothing contaminated with Somán or any other nerve agent may continue to release the agent for the next 30 minutes after becoming contaminated. However, the Somán in the form of vapor is heavier than air, so it expands to the lower areas creating greater danger in these places.
Decontamination: considerations on Sarin (GB) decontamination, are perfectly applicable to the decontamination of surfaces contaminated by Somán (GD) (whether on surfaces of materials and vehicles or on the human body), CBRN decontamination protocols Generally they define their neutralization by means of the fast and exhaustive washing of the skin with water and a dermogel (specific decontaminating agents for its use on people). This washing should be done for a period of 5 -10 minutes. In the case of the decontamination of materials contaminated by Somán (GD), large quantities of water and alkaline media (decontaminating agents) are used.
2. 2 Nervous agents Series V
Nerve agents Servies V are mainly alkyl esters of S-dialkylaminoethylmethylphosphonothiol acid and act mainly through penetration of the skin and inhalation of aerosols. In this category is VX agent.
VX agent
Description: VX, also known as Oetil S-2- (diisopropylamino) ethyl methylthiophosphonothiolate, was originally developed in the United Kingdom in the early 1950s. It is an oily, odorless, tasteless, amber-colored liquid that takes a long time to evaporate .
Exposure: By inhalation or by contact with skin and eyes. The lethal dose by inhalation is 50 LCt50 and per contact is 10 LD50.
Symptoms: Disabling effects appear rapidly, within the first 10 minutes after exposure, and lethal effects occur between 4 and 42 hours after exposure. A single drop of this agent in liquid form can cause sweating and muscle contraction of the affected area. Mild or moderate doses produce diffuse muscle cramps, rhinorrhea, dyspnea, eye pain, blurred vision and sweating. Exposure to high doses causes the above symptoms plus sudden loss of consciousness, seizures, flaccid paralysis and respiratory failure that can lead in most cases to the death of the affected person
Treatment: Exposure with this type of agents should be treated with anticholinergics such as atropine, anticonvulsants such as Diazepam and acetylcholinesterase activators, such as Pralidoxime.
Stability / Persistence: Although VX does not dissolve in water as easily as other nerve agents do, it can also be released that way. The greatest risk of exposure is in liquid form, but if heated at high temperatures, small amounts can be transformed into gas.
Decontamination: considerations on decontamination for nerve agents G series (Tabún, Sarín, Somán) are also applicable to the decontamination of nerve agents V series such as the nerve agent VX, that is, for the decontamination of surfaces contaminated by VX gas, CBRN decontamination protocols generally define their neutralization by fast and thorough washing of the skin with water and a dermogel (specific decontaminating agents for use on people). This washing should be done for a period of 5 -10 minutes. In the case of decontamination of materials contaminated by VX agent , large quantities of water and alkaline media (decontaminating agents) are used.
3. Blood Agents
Blood or hemotoxic agents, are so named, because they are absorbed and transported by the blood, having a systemic effect. They act by interfering in the oxygen-CO2 exchange of blood hemoglobin. Typical blood agents are cyanide and its derivatives, or carbon monoxide. These when in contact with the Hemoglobin of the blood form the compound Cano-Hemoglobin, this compound unlike the Hemoglobin is stable and does not react neither with Oxygen, nor with CO2, so it blocks both the transport of Oxygen, as the elimination of CO2. This occurs not only in the lungs, but also at the cellular level, causing the total dysfunction of the vital organs, entering the affected in coma and dying in a short time.
Effects on exposed personnel: This type of Agents acts very quickly and practically irreversibly, with death being the final result in most cases. The only possibility is to carry out an emergency transfusion in the moments after the exposure, this being practically impossible the vast majority of the time, although in general, a patient who has survived the inhalation exposure long enough to receive medical care, you will need them in a minimum degree.
Decontamination: This type of agents can be solid, liquid and gaseous, examples of each are Potassium Cyanide (The “poison of the Spies”) Hydrogen cyanide (Derived from the previous and widely used in the chemical industry) or the Monoxide of Carbon, respectively.
Decontamination procedure depends not only on its chemical composition but also on its nature, so it will not act the same in the case that they are solid or liquid or gases.
In the case that they are gases, the most effective thing is simply to ventilate the area with clean air. Being compounds in which the toxicity depends on its concentration, if we ventilate until the concentration falls below the threshold of danger we eliminate all risk, since on the other hand are compounds that degrade naturally.
If we are talking about liquids and solids, we will have to resort to reagents that by means of hydrolysis and oxidation reactions chemically attack the Chemical Agents, degrading them into innocuous compounds.
Hydrogen cyanide or hydrocyanic acid (AC)
Description: Hydrogen cyanide (HCN), also known as hydrocyanic acid or with the military term AC is a colorless gas that under the name of Zyklon B was used as a genocidal agent in World War II by the Germans, and according to several reports it was possibly used, along with other chemical agents, against the inhabitants of the Kurdish city of Halabja, in northeastern Iraq, during the Iran-Iraq war in the 1980s. It is a lethal fast-acting agent that inhibits aerobic respiration at the cellular level, by inhibiting cytochrome oxidase, preventing the use of oxygen and accumulating lactic acid in cells, which eventually die of histotoxic anoxia. Its smell, at low concentrations, is similar to bitter almonds or marzipan, which facilitates its detection. Available in the chemical industry as an intermediate product, it is used to produce paper, textiles and plastics. Also present naturally in some foods and in certain plants such as Cazabe. It is used as a pesticide, rodenticide and fumigant.
Exposure: The main entry route is inhalation and contact with the skin.
Symptoms: Symptoms start quickly because the gas is rapidly absorbed from the lungs causing hyperventilation, which increases with the dose inhaled. At low doses, individuals may experience dyspnea, headache and vertigo, noticing a metallic taste in the mouth. At high concentrations, loss of consciousness occurs, seizures and loss of corneal reflex, resulting in death from cardiac or respiratory arrest
Treatment: The first step to follow is the prompt administration of oxygen, followed by antidotes that dissociate the cyanide ion from cytochrome oxidase such as sodium thiosulfate, sodium nitrite, 4-dimethylaminophenol or cobalt.
Stability / Persistence: Hydrogen cyanide is unstable, highly volatile and non-persistent, which degrades slowly in the atmosphere and if mixed with water.
Decontamination: Due to the high volatility of AC agent, its decontamination presents a very particular casuistry: this high volatility supposes a very rapid evaporation of AC agent from the contaminated surface (human body or other materials). However, CBRN decontamination protocols continue to define the need to carry out the decontamination process similar to that of other chemical warfare agents (CWAs). In this specific case, for the decontamination of people, it is necessary a quick and thorough washing of the skin with water and a dermogel (specific decontaminating agents for use on people). This washing should be done for a period of 5 -10 minutes. In the case of the decontamination of materials (vehicles, floors, buildings, First Responders protection suits, etc.) contaminated by the AC agent, large quantities of water and alkaline media (decontaminating agents) are used
Cyanogen chloride (CK)
Description: Cyanogen chloride (ClCN) or CK (military term) is a colorless gas with an acrid odor. It was the first blood agent proposed by the French for use as an agent of chemical warfare.
Exposure: Via inhalation, by contact with skin and eyes or ingestion of contaminated food or water.
Symptoms: At low doses the initial symptoms are weakness, headache, confusion, nausea, vomiting and stiffness of the jaw. If the picture gets worse, violent convulsions appear without loss of consciousness, after which paralysis may occur. When the poisoning is severe, the symptoms that appear are cyanosis, mydriasis, bradycardia followed by tachycardia, increased blood pressure and irregular breathing. Inhalation of high concentrations of this compound can lead to unconsciousness and death due to respiratory paralysis.
Decontamination: Due to the high volatility of CK agent, its decontamination presents a very particular casuistry: this high volatility supposes a very rapid evaporation of CK agent from the contaminated surface (human body or other materials). However, CBRN decontamination protocols continue to define the need to carry out the decontamination process similar to that of other chemical warfare agents (CWAs). In this specific case, for the decontamination of people, it is necessary a quick and thorough washing of the skin with water and a dermogel (specific decontaminating agents for use on people). This washing should be done for a period of 5 -10 minutes. In the case of the decontamination of materials (vehicles, floors, buildings, First Responders protection suits, etc.) contaminated by CK agent, large quantities of water and alkaline media (decontaminating agents) are used.
4. Blister Agents
Blister agents are substances that can be solid, liquid or gaseous and that in contact with the skin produce irritation and blisters. Its action ranges from mild irritation of the skin to ulceration and severe burns, leading to the destruction of tissues. The eyes are an area especially sensitive to them. Also, in the case of being ingested or aspirated, they can produce a suffocating effect due to their vesicant action in the trachea and bronchi (the dead cells produced by this action can obstruct them). They are alkylating substances that react with the nitrogenous bases of DNA / RNA. The main blistering agents are: Sulfur Mustard (HD) or Iperite, Nitrogen Mustard (HN) and Lewisite (L).
Sulfur Mustard(HD)
Description: Also known as sulfur mustard, Iperite or bis (2-chloroethyl) sulfide. It is an oily colorless or amber colored liquid, neutral reaction. At high concentrations, it has a pungent odor that resembles that of radish, garlic or onion. Slightly soluble in water, but can be dissolved in organic solvents and grease. When it dissolves in water, it is first hydrolyzed and then oxidized resulting in sulphoxide and sulfone, less toxic products. The hydrolysis of mustard gas produces hydrochloric acid and thioglycols or thioeters. And its combustion gives rise to hydrochloric acid and sulfur oxides. Hydrochloric acid is highly toxic, causing the destruction of internal tissues.
Exposure: By inhalation and contact with the skin and eyes. The effect on the skin starts after a 10-minute exposure at concentrations of 15 ppm and in eyes with concentrations of 3 ppm after 10 minutes of exposure. The lethal dose by inhalation is 1500 LCt50 and by contact with the skin is 4500 LD50.
Symptoms: Symptoms develop gradually after an interval of several hours, depending on the form of exposure and the ambient temperature. The first defined symptoms appear in the eyes, in a period of between 30 minutes and 3 hours after exposure, appearing an acute conjunctivitis, with pain, lacrimation, blepharospasm and photophobia. Then there is an increase in nasal secretions, sneezing, sore throat, coughing and hoarseness. After 4-16 hours of exposure, the above symptoms are accentuated and nausea, retching and vomiting associated with epigastric pain appear. In severe cases, the above symptoms can become intense and prolonged.
During this period, the skin begins to redden and itch to form an erythema. With severe or moderate exposure can form yellowish blisters, which when they burst cause erosions and loss of the total thickness of the skin and ulceration. The blisters heal in 2 or 3 weeks and the erosions of the skin in 6-12 weeks leaving a scar hypersensitive to mechanical trauma. After 24 hours, all these symptoms can be increased in intensity. In severe cases, inflammation of the upper and lower respiratory tract becomes visible during the second day. The expectoration becomes abundant and muco-purulent, sometimes can lead to bronchopneumonia, with death at any time between the second day and the fourth week. Recovery is slow and expectoration and cough may persist for several weeks.
Treatment: There is no antidote, only symptomatic treatment. Erythemas of the skin are treated with calamita solution, the small ampoules are left intact and the large ones are broken very carefully and the area is treated 3 or 4 times a day with sterile saline and antibiotic.
Stability / Persistence: Mustard gas can be very persistent in the environment, depending on the temperature, being really dangerous at temperatures below 0ºC, being able to remain in the soil for years if the conditions are adequate. The painted surfaces can absorb this gas for a while and then release it.
Decontamination: to decontaminate surfaces contaminated by Sulfur Mustard (HD), CBRN decontamination protocols determine that for the decontamination of people a quick and thorough washing of the skin with water and a dermogel (specific decontaminating agents for its use on people). In the case of decontamination of materials (building interiors, First Responders protective suits, ground, vehicles, etc.), CBRN protocols recommend several alternatives for decontamination: Hypochlorite solution, neutral absorbent powders (fuller´s earth, diatomeas, etc.).
Nitrogen Mustard (HN)
Description: Nitrogenized vesicants can be in liquid or solid form. Solid agents are not used in the military framework. The liquid agents can be from colorless to oily yellow. This type of vesicants can be odorless, have fishy odor or moisture at low concentrations, and at high concentrations can have fruity odor. Some of the nitrogenous mustards that can be used as chemical warfare agents are: 2-chloro-ethyl-amine (HN3), 2-chloro-ethyl-methyl-amine (HN2) or 2-chloro-ethyl-ethyl-amine (HN1) ). The hydrolysis of the nitrogen mustard generates hydrochloric acid and ethanol-amine and, by combustion, hydrochloric acid and nitrogen oxides are generated.
Exposure: Through inhalation, contact with skin and eyes or even accidental ingestion. The lethal dose by inhalation is 1500 LCt50 and per contact is 4500 LD50.
Symptoms: Mild exposure to steam does not cause skin lesions. There is a period of asymptomatic latency of 4 to 24 hours followed by inflammation and redness of the skin that precedes the appearance of the vesicles. The effect on the eyes, which appears immediately, includes irritation, tearing, sensitivity to light and even inflammation. Large amounts of vapor cause swelling of the eyelids and pain in the eyes can cause spasms and sometimes total blindness. Symptoms by ingestion vary depending on the amount ingested and include nasal irritation, abrasive throat, laryngitis and choking sensation
Treatment: There is no antidote against nitrogen mustard. The treatment is symptomatic and the immediate decontamination of the individual is vital.
Stability / Persistence: Its efficiency depends on the ammunition used and weather conditions. They are the most persistent vesicants under appropriate conditions, and can remain in the soil for years. These types of agents have a higher density than air and tend to settle in low places. In liquid form they persist for 2 days and even for more than a week in low temperature conditions, and can be absorbed by porous materials, including painted surfaces, and can disperse steam even after exposure has ceased. The solubility in water is in a range that ranges from moderate to insoluble solubility. The liquid density of these agents is greater than that of water.
Decontamination: to decontaminate surfaces contaminated by Nitrogen Mustard (HN), CBRN decontamination protocols determine that for the decontamination of people a quick and thorough washing of the skin with water and a dermogel (specific decontaminating agents for its use over people). In the case of decontamination of materials (interior of buildings, vehicles, ground, protective suits etc.), CBRN protocols recommend several alternatives for decontamination: Hypochlorite solution, neutral absorbent powders (fuller´s earth, diatomeas, etc.).
Lewisite (L)
Description: It is also known as 2-chlorovinyldichloroarsine. It is a colorless oily liquid that freezes at -18ºC and boils at 190ºC. Practically insoluble in water, but freely soluble in organic solvent. It hydrolyzes quickly when mixed with water or dissolved in aqueous alkaline solutions such as sodium hypochlorite solution. It has the smell of geraniums. Hydrolysis of this compound results in hydrochloric acid and oxides and arsenic salts, some of which may have properties typical of vesicants. Its combustion also generates hydrochloric acid and arsenic oxides.
Exposure: By inhalation or by skin contact. It is approximately 7 times less persistent than mustard gas. The lethal dose by inhalation is 1300 LCt50 and per contact is 4500 LD50.
Symptoms: Even having a shorter latency period than mustard gas, the symptoms are very similar, starting with immediate eye irritation and blepharospasm, followed quickly by coughing, sneezing, watering and vomiting. In concentrations of 0.005 to 0.1 mg / cm2 it produces erythema, at 0.2 mg / cm2 it produces vesicles and a 15 minute exposure at a vapor concentration of 10 mg / m3 produces conjunctivitis. In the skin, there is a sensation of burning, erythema and blisters that after a few hours are painful and reach their maximum size after 4 days. Eye injuries can be serious and even blind if rapid decontamination does not occur. Symptoms by inhalation begin with difficult breathing followed, in severe cases, pseudomembrane formation and pulmonary edema. Hepatic and systemic toxicity due to arsenic can appear after a large cutaneous contamination.
Treatment: Treatment with Dimercaprol is the standard treatment for intoxication with arsenic compounds as it acts as a chelator and is available in intramuscular injections, ointments and eye drops. Intramuscular doses are limited due to its systemic toxicity. Currently, there are two water-soluble analogs of this compound, meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-1-propanesulfonic acid (DMPS), which are less toxic and can be administered orally or intravenously. As with mustard gas, Lewisite bound to hemoglobin and urine can be detected up to 12 hours after exposure.
Stability / Persistence: These agents are less persistent than mustards because the vapors react rapidly to high humidity, losing most of their vesicant properties. The limited solubility reduces the hydrolysis of liquid agents.
Decontamination: to decontaminate surfaces contaminated with Lewisite (L), CBRN decontamination protocols determine that for the decontamination of people a quick and thorough washing of the skin with water and a dermogel is necessary (specific decontamination agents for use on people ). In the case of decontamination of materials (interior of buildings, First Responders protective suits, vehicles, ground, etc.), CBRN protocols recommend several alternatives for decontamination: Hypochlorite solution, neutral absorbent powders (fuller´s earth, diatomeas, etc.).
5. Choking agents
Choking agents or suffocating substances cause physical damage to the lungs. The exposure must be through inhalation. The pulmonary membranes swell and fill with fluid (pulmonary edema). Death ensues due to lack of oxygen. The main suffocating agents: Chlorine, Phosgene (CG), Diphosgene (DP) and Chloropicrin (PS) are characterized because their symptoms do not appear until several hours have elapsed since their exposure.
Chlorine
Description: It is a greenish yellow gas at room temperature, easily liquefied at a pressure greater than or equal to 7 atmospheres at 20 ° C. Of irritating smell, very concentrated is dangerous; It was the first substance used as a gas of war in the First World War. It is currently rarely used as a weapon, but it is a gas widely used in the chemical industry and can be the result of industrial accidents or civil activities that are apparently innocuous, such as swimming pool maintenance. Chlorine is part of the halogens in the periodic table, forms numerous salts and is obtained from its chlorides. It is very reactive and easily combined with most of the elements. It is slightly soluble in water (about 6.5 g of chlorine per liter of water at 25 ° C), forming hypochlorous acid in part. It is used to purify drinking water, but it is also used as an oxidant, bleach and disinfectant.
Exposure: Through inhalation and contact. Chlorine gas is irritating and corrosive to the respiratory tract, eyes and skin. The effects depend on the amount to which it is exposed and the duration of the exposure. Its lethal dose is 3000 LCt50.
Symptoms: At low concentrations, chlorine gas (1 to 10 ppm) causes sore throat, cough and irritation in eyes and skin. Exposure to higher concentrations causes burns, rapid breathing, narrowing of the bronchi, panting, blue discoloration of the skin and accumulation of fluid in the lungs. Higher concentrations can cause severe burns to eyes and skin, lung collapse and death. A concentration greater than 2.5 mg / l in air causes death in a few minutes. It is detected by the smell at concentrations that are not dangerous. Occasionally, an inflammatory reaction to chlorine occurs. This condition is known as Respiratory Tract Malfunctioning Syndrome (RADS), which is a type of asthma caused by certain irritating or corrosive substances. On the other hand, if the liquid chlorine comes in contact with the skin, it can freeze it. Ingestion of a product containing sodium hypochlorite can produce corrosive gas chlorine in the stomach and cause serious injury.
Treatment: It is non-specific. Recently, the use of sodium bicarbonate aerosol administration has been seen to avoid lung damage, thus reducing stays and number of hospitalizations.
Stability / Persistence: The duration of effectiveness is short, and the range of hydrolysis is low.
Decontamination: to decontaminate surfaces contaminated by chlorine, CBRN decontamination protocols determine that for the decontamination of people a quick and thorough washing of the skin with water and a dermogel (specific decontaminating agents for use on people) is necessary. In the case of decontamination of materials (First Responders protective suit, vehicles, building interiors, ground, etc.) CBRN decontamination protocols determine the use of large quantities of water with alkaline solutions (decontaminating agents developed for this purpose).
Phosgene
Description: Phosgene or carbonyl dichloride is a colorless, non-flammable gas with the smell of freshly cut hay. At room temperature it is gas, but it can be stored as a liquid under pressure. Most of the victims of World War I were low caused by phosgene.
Exposure: Exposure occurs by inhalation and its objective is the lung. The damage that occurs in the lungs is directly proportional to the concentration and the time of exposure to this agent. The lethal dose of phosgene is 3200 LCt50.
Symptoms: Exposures at 2 ppm for 80 minutes do not cause any irritation but have an impact on pulmonary edema at 12-16 hours later. Starting at 3 ppm, the symptoms are burning and tearing of the eyes, pain or discomfort of the throat, dry cough and chest tightness.
At high concentrations, the sense of smell is lost and, therefore, the ability to assess the danger. When the concentration is higher, erythema of the oral and pharyngeal mucous membranes occurs. And above 200 ppm, the phosgene crosses the blood-air barrier and causes hemolysis in the pulmonary capillaries, congestion by fragments of erythrocytes and obstruction of the capillary circulation. Death occurs in a few minutes. Most survivors of acute exposure have a good prognosis, but dyspnea and reduced physical activity may persist for the rest of their lives in some patients. Contact with liquid phosgene can cause lesions or blisters on the skin.
Treatment: The skin and eyes should be washed with running water for 15-20 minutes. Keep in mind that normally irritation precedes pulmonary edema, but not always.
Stability / Persistence: Its effectiveness is short. However, Phosgene is very persistent in the atmosphere, it is estimated that its average life in it is more than 100 years at sea level. Its persistence is due to the fact that it does not absorb UV light, so it does not decompose by photolysis. On the other hand, rain and abundant vegetation affect its effectiveness because they favor its hydrolysis.
Decontamination: to decontaminate surfaces contaminated by Phosgene, CBRN decontamination protocols determine that for the decontamination of people a fast and thorough washing of the skin with water and a dermogel (specific decontaminating agents for its use on people) is necessary. In the case of decontamination of materials (Intervener protective suits, ground, vehicles, building interiors, etc) CBRN protocols determine the use of large quantities of water with alkaline solutions (decontaminating agents developed for this purpose).
Chloropicrin
Description: Chloropicrin or Trichloronitro-methane is a tear and irritant. It is an oily, colorless or greenish-yellow liquid. It decomposes at high temperatures and exposure to light, forming toxic gases such as phosgene, hydrogen chloride, nitrogen oxides and carbon monoxide. It has been used as a Chemical War Weapon, employing itself as a lethal, harassing and training agent.
Exposure: Exposure occurs mainly by inhalation, but also by contact and even by ingestion. Its lethal dose is 20,000 LCt50.
Symptoms: Exposure causes eye, nose and throat irritation, tearing and dry cough. Other symptoms include dizziness, fatigue, headache. Depending on the concentration can cause significant lung damage (Edema and airway injuries) The odor of Chloropicrin is detectable by humans from 1.1 ppm, above that value causes eye irritation. At concentrations of 0.3-1.35 ppm causes painful irritation of the eyes and concentrations of 1 to 3 ppm cause tearing. Exposures to 4 ppm cause clumsiness and 15 ppm, cause lesions in the respiratory tract. Ingestion produces nausea, vomiting, cramping and diarrhea. A 30-minute exposure at a concentration of 120 ppm and a 10-minute exposure at 300 ppm leads to the death of the exposed individual.
Higher concentrations are lethal after shorter exposure periods.
Treatment: In case of contamination by contact with the skin, the affected areas should be washed with soap and warm water. It is necessary to wash for 20 to 30 minutes and any contaminated clothing should be removed. If there is eye contact, they should be washed repeatedly with warm water for 20 minutes. If there has been an intoxication by ingestion, do not induce vomiting, but encourage the patient to drink water or liquids. Edema may be delayed after inhalation, but should be detectable at 48 hours. The positive pressure of the airways will help breathing. Oxygen should be administered if the patient is hypoxic or cyanotic and fluids if the patient is hypotensive.
Stability / Persistence: Little persistent.
Decontamination: to decontaminate surfaces contaminated with Chloropicrin, CBRN decontamination protocols determine that for the decontamination of people a quick and thorough washing of the skin with water and a dermogel (specific decontaminating agents for use on people) is necessary. In the case of decontamination of materials (First Responder protective suits, Intervener equipment, vehicles, etc.) CBRN protocols determine the use of large quantities of water with alkaline solutions (decontaminating agents developed for this purpose).
