Lachrymators

When you hear the word teargas you think, well, your eyes will burn and that's it. But that whole feeling of your whole skin burning, that you can't breathe, you can't inhale, you feel suffocated - it's a very, very terrifying experience.

Haskell Wexler

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Lachrymators cause irritation to the eyes, and hence tears. They are commonly called tear gases. Lachrymators are regarded now as riot control agents. Generally they cease to have any effect shortly after exposure ceases, although very high levels of exposure to some of the agents may cause long-term effects. The use of riot control agents as a method of warfare is prohibited by the CWC, in 2022 it was claimed Russia used them in the war with Ukraine, inititially identified as chlorine, then as chloropicrin, this was later corrected to CS.

1-Bromo-2-butanone [Bromomethylethyl ketone, 1-bromobutan-2-one, Bromomethyl ethyl ketone, Homomartonite, Bn-Stoff] - CH₃COCHBrCH₃

A colourless to straw-colored liquid. Toxic by inhalation, skin contact or ingestion. May cause burning of eyes and lachrymation (flow of tears)osure in an enclosed area may be very harmful. Burning will produce irritating, corrosive and/or toxic gases.

2-Chloroacetophenone [Chloroacetophenone, CN] - C₆H₅COCH₂Cl 

A white crystalline solid, dense than water and insoluble in water, with a floral odour.  It is a potent eye, throat, and skin irritant. Acute (short-term) inhalation exposure of humans causes burning of the eyes with lachrymation, some degree of blurred vision, possible corneal damage, irritation and burning of the nose, throat, and skin, and burning in the chest with dyspnea. Acute dermal exposure is irritating and can result in first, second, and third degree chemical burns.

2-chlorobenzalmalononitrile  [CS, o-chlorobenzylidene malononitrile] - C₁₀H₅ClN₂

A white crystalline solid or light beige powder, with an odour of pepper. Exposure causes a burning sensation and tearing of the eyes to the extent that the subject cannot keep their eyes open, and a burning irritation of the mucous membranes of the nose, mouth and throat, resulting in profuse coughing, nasal mucus discharge, disorientation, and difficulty breathing, partially incapacitating the subject. CS gas is an aerosol of a volatile solvent (a substance that dissolves other active substances and that easily evaporates) and 2-chlorobenzalmalononitrile, which is a solid compound at room temperature. CS gas is generally accepted as being a non-lethal weapon. Banned for use in warfare pursuant to the 1925 Geneva Protocol.

2-Methylbenzyl bromide [1-(Bromomethyl)-2-methylbenzene, alpha-Bromo-o-xylene, Xylyl bromide, T-Stoff] - C₆H₄CH₃CH₂Br

A colourless liquid in pure form but may appear yellowish as it ages or in the impure product. It has a pleasant aromatic smell. Causes skin irritation and  serious eye irritation. 2-Methylbenzyl bromide is flammable.

Acrolein [Papite, Propenal, Acrylaldehyde] - CH₂CHCHO 

A colourless liquid with a piercing, disagreeable, acrid smell. The smell of burnt fat, as when over cooking fried bacon or steak is caused by glycerol in the burning fat breaking down into acrolein. Initially irritating to the eyes and mucous membranes. Very toxic by inhalation. It dissolves in water very easily and quickly changes to a vapour when heated. It also burns easily. Symptoms of single or short-term exposure to acrolein may include irritation to the eyes, skin and the mucous membranes of the respiratory and gastrointestinal systems. It can be corrosive. Exposure can lead to decreased pulmonary function, pulmonary oedema (a build up of fluid in the lungs, characterised by severe shortness of breath), and chronic respiratory disease.

Longer term exposure to acrolein may result in general respiratory congestion and eye, nose and throat irritation. Systemic effects to the respiratory, reproductive, neurological and haematological systems may also result.

Benzyl bromide [Cyclite, T-Stoff, Bromotoluene] - C₆H₅CH₂Br

A colourless to yellow liquid, with a strong, sharp, pungent odour.  Intensely irritating and corrosive to skin, eyes, and mucous membranes. Large doses cause central nervous system depression. Combustible, giving off irritating or toxic fumes (or gases) in a fire.  Above 79°C explosive vapour/air mixtures may be formed. It is slightly soluble in water and denser than water (density 1.44 g / cm3 (Aldrich)). Corrosive to metals and tissue.

Benzyl iodide [Fraissite, alpha-iodotoluene, iodomethylbenzene, iodo-methyl-benzene) - C₆H₅CH₂I

Colourless to yellow needle like crystalline solid, melting at 24.5 °C. Benzyl iodide has the same structure as the bromide, but with an iodine atom replacing the bromine atom. Toxic by ingestion, inhalation and skin absorption. Very irritating to skin and eyes.  Insoluble in water and denser (1.74 g / cm3) than water, hence it sinks in water. Toxic by ingestion, inhalation and skin absorption. Very irritating to skin and eyes. Inhalation, ingestion or contact (skin, eyes) with vapours, dusts or substance may cause severe injury, burns or death. Contact with molten substance may cause severe burns to skin and eyes. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat that will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

Bromoacetone [Martonite, BA, B-Stoff, 1-Bromo-2-propanone, 1-bromopropan-2-one, Monobromoacetone] - CH₃COCH₂Br 

A clear colorless liquid turning violet on standing, even in the absence of air, and decomposing to a black resinous mass on long standing. A violent lachrymator, low concentrations are very irritating to the eyes; high concentrations or prolonged exposure at lower concentrations may have adverse health effects. Very toxic by inhalation. Contact with the liquid causes painful burns.

Bromobenzyl cyanide [Camite, CN, , Bromo(phenyl)acetonitrile] - C₆H₅CHBrCN

Yellowish crystalline sold that melts to an oily liquid at room temperature. Extremely irritating to the eyes, and can burn them. The liquid or solid in contact with the skin can cause burns. High level exposure can cause headache, palpitations, weakness and breathing problems possibly leading to death.  It is slightly soluble in water but readily soluble in organic solvents. Bromobenzyl cyanide is resistant to the action of water and oxidizers; it decomposes upon heating above 120° C and also when exposed to the action of a number of metals, which are thereby intensely corroded.

Chloroacetone [Chloropropanone, Tonite, A-Stoff, 1-Chloropropan-2-one, Monochloroacetone] - CH₃COCH₂Cl

A colourless to yellow-colored liquid, on aging it darkens with an irritating pungent odour. Chloroacteone has the same structure as bromoacetone, but with the bromine atom replaced by a chlorine atom. Chloroacetone isight sensitive, but can be stabilised with the addition of small amounts of water and/or calcium carbonate. Slightly soluble in water and denser than water. Vapours much heavier than air. Exposure causes immediate, intense irritation to the eyes, nose, and skin, with symptoms including tearing (lacrimation), stinging, nausea, vomiting, breathing difficulties, and in high concentrations, damage to the cornea or pulmonary oedema. It is highly toxic, flammable, and can form explosive vapor/air mixtures above 28°C.

Chloropicrin [Trichloronitromethane, Nitrochloroform, Aquinite, PS, NC, Klop] - CCl₃NO₂

A colourless to slightly yellow liquid with a strong, irritating odor. It is commonly used as a pesticide and soil fumigant but can also be found in chemical warfare agents and tear gas. Its effects on health can be quite severe, depending on the route and level of exposure. Chloropicrin (CCl₃NO₂) exposure can cause severe irritation to the eyes, skin, and respiratory system, leading to symptoms such as coughing, shortness of breath, and tearing. High concentrations may result in more serious health effects, including lung damage, chemical burns, and, in extreme cases, respiratory failure. It has been claimed that Russia used chloropicrin during the current Russo-Ukranian war.

Dibenzoxazepine [CR] - C1₃H₉NO

Yellow solid with an odour of pepper; powder is dispersed using a small explosive or dissolved in a solvent and water and sprayed. A lachrymatory agent, its effects are approximately 6 to 10 times more powerful than those of CS gas. CR causes intense skin irritation, in particular around moist areas; blepharospasm, causing temporary blindness; and coughing, gasping for breath, and panic. It is capable of causing immediate incapacitation. It is a suspected carcinogen. It is toxic, but less so than CS gas, by ingestion and exposure. However, it can be lethal in large quantities. In a poorly ventilated space, an individual may inhale a lethal dose within minutes. Death is caused by asphyxiation and pulmonary edema. The effect of CR is long-term and persistent. CR can persist on surfaces, especially porous ones, for up to 60 days.

Ethyl bromoacetate  [Ethyl 2-bromacetate, Antol] - CH₂BrCOOC₂H₅ 

A clear, colourless liquid with a fruity, pungent odor.  A skin, eye, and mucous membrane irritant exposure to 8 ppm for more than 1 minute is unbearable. Contact with liquid can cause corneal burns. A lachrymator and a strong skin irritant.Highly toxic. Inhalation of high concentrations may produce acute pneumonitis and pulmonary edema.

Ethyl iodoacetate  [SK, ethyl 2-iodoacetate, Ethyl monoiodoacetate] - CH₂ICOOC₂H₅

A clear, light yellow to orange liquid that rapidly turns brown and releases iodine when in contact with air. It is toxic, and causes severe irritation to the skin, eyes and respiratory system. Ethyl iodoacetate has the same structure as Ethyl boromoacetate, but with the bromine atom replaced with an iodine atom. It is highly flammable.

Iodoacetone [1-iodopropan-2-one, Bretonite, 1-Iodoacetone, 1-Iodo-2-propanone, 1-iodopropan-2-one] - CH₃COCH₂I

Iodoacetone has the same molecular structure as Bromoacetone, but with the bromine atom replkaced by an iodine atom. Iodoacetone is a severe irritant to the eyes, skin, and respiratory tract, causing intense lacrimation, coughing, sneezing, and excessive mucus production even at low airborne concentrations of 0.007 mg/L. These effects stem from its reactivity as an alkylating agent, where the iodine atom facilitates nucleophilic substitution with sulfhydryl (-SH) groups in receptor proteins at sensory nerve endings, triggering immediate inflammatory responses. Upon higher exposure or prolonged contact, iodoacetone can lead to systemic toxicity through alkylation of essential biomolecules, such as thiol groups in enzymes, resulting in symptoms including nausea, abdominal cramps, chest pain, and respiratory distress. The minimum lethal concentration via inhalation is reported as 0.35 mg/L, potentially causing severe pulmonary damage. Long-term risks include potential carcinogenicity arising from its alkylating mechanism, which can damage DNA and proteins, although specific studies on iodoacetone are limited and primarily inferential from similar haloacetones. Occupational exposure during synthesis heightens these concerns, necessitating stringent controls to prevent chronic effects.

Phenylcarbylamine chloride [Phenylisocyanide chloride, Phenyl isocyanide chloride, Phenylcarbylamine chloride, Phenyl isocyanide dichloride, Phenylcarbonimidic dichloride, N-(Dichloromethylene)aniline] - C₆H₅CNCl₂

An oily liquid with an onion-like odour. A lung irritant with lachrymatory effects. Highly toxic by inhalation and skin absorption. Strongly irritates skin and mucous membranes. Density 1.265 g / cm3. Insoluble in water and soluble in alcohol. Noncombustible.