Carbonyl chloride [CG, Phosgene] - COCl₂

One of very few choking agents that are considered likely to be used in warfare today. It is a colourless gas; in low concentrations, its odour resembles freshly cut hay, but the smell may be so slight as to be undetectable by odour. At high concentrations it has a strong, pungent disagreeable smell.  Because carbonyl chloride is used in a number of manufacturing processes from plastics to pesticides it is readily available in large quantities. It is also easy to synthesise. It is relatively easy to liquify. When liquid phosgene is released, it quickly turns into a gas that stays close to the ground and spreads quickly.

Signs and symptoms of exposure depend on how the person was exposed, how much they were exposed to, and how long.

During or immediately after exposure to dangerous levels of phosgene, the following signs and symptoms may develop: chest tightness, coughing, choking, burning sensation in the respiratory tract, and eyes, blurred vision, lachrymation, shortness of breath, rapid shallow breathing, frostbite if exposed to liquid phosgene, headache, nausea and vomiting. These signs and symptoms may also be delayed for up to 48 hours.

There are other delayed effects that may not show for up to 48 hours. These effects include:  breathing difficulty, coughing up white to pink-coloured fluid (sign of pulmonary edema), low blood pressure, respiratory failure, heart failure.

Chlorine [Bertholite, Red Star, Chlor] - Cl₂

Chlorine gas can be recognized by its pungent, irritating odour, it smells like bleach which contains high concentrations of chlorine. The strong smell may provide adequate warning to people that they are exposed. Chlorine gas is yellow-green in colour. Chlorine is readily liquified.

Chlorine can explode or create explosive products with many common substances. They include: acetylene, ether, turpentine, ammonia, fuel gas, hydrogen, and finely divided metals.

Most people will smell the chemical or feel irritation that tells you that you are exposed to chlorine. Exposure for a long time may affect people's ability to sense the chemical. Some people with asthma or other lung diseases may be more sensitive to breathing chlorine than others.

Effects depend on how the person was exposed, how much they were exposed to, and how long they were exposed for.

When chlorine gas touches moist tissues (like the eyes, throat, and lungs) it creates an acid that can injure these tissues.

If high amounts are breathed in, breathing problems may show up right away. Symptoms of exposure to higher levels of chlorine include the following: blurred vision, lachrymation, burning sensations in the respiratory tract, coughing, coughing up white to pink-coloured fluid (sign of oedema), chest tightness, shortness of breath, rapid and shallow breathing, respiratory failure, frostbite if exposed to liquid chlorine, nausea, vomiting, skin pain,  (with erythema, blisters). If low amounts are breathed in, symptoms may show up later.

Because chlorine gas is heavier than air, it will sink to lower areas and increase the risk of exposure there.

Chlormethyl chloroformate [Palite, K-stoff, C-Stoff] - ClCOOCH₂Cl

Chloromethyl chloroformate appears as a colourless liquid at normal temperatures with a penetrating, irritating odor. It is denser than water.  It is toxic by ingestion, inhalation and skin absorption.  Inhalation, ingestion or contact (skin, eyes) with vapour or liquid may cause severe injury, burns or death. When it comes into contact with moist tissues such as the eyes, throat, and lungs, an acid is produced that can damage these tissues. Acute Symptoms of Exposure
Inhalation: Exposure to vapors causes immediate irritation to the nose and throat, coughing, labored breathing, and shortness of breath. It is fatal if inhaled, and severe exposure can cause pulmonary edema (a build-up of fluid in the lungs). Skin contact: causes severe skin burns, pain, and blistering. It is absorbed through the skin, potentially leading to systemic toxicity. Causes severe eye damage, deep burns, pain, and redness, with the risk of permanent blindness.
Ingestion: Causes severe burns to the digestive tract, resulting in a burning sensation in the mouth and throat, abdominal pain, shock, or collapse. Symptoms of pulmonary edema can be delayed for several hours after exposure and are often worsened by physical exertion.

Chloropicrin [Nitrochloroform, Aquinite, PS, NC, Klop, vomiting gas] - CCl₃NO₂

A colorless to faintly yellow oily liquid, which vapourises readily. It has an intensely irritating odour. Inhalation of 1 ppm causes eye irritation and can warn of exposure. Historically described as smelling like “fly paper,” it was first patented in 1908 as an insecticide. With increasing dose or prolonged exposure (likely because chloropicrin breakdown products include both chlorine and phosgene), death can occur from pulmonary edema. It acts as a severe eye and respiratory irritant - often classified as tear gas or a choking agent, causing pulmonary edema, vomiting, and skin burns.

It is extremely toxic if inhaled, with an Immediate Danger to Life and Health (IDLH) value of 2 ppm. It acts as a lung-damaging agent, capable of causing severe pulmonary edema and severe eye damage. Symptoms of exposure include: Intense lachrymation, irritation of the eyes, and potential eyelid swelling, coughing, wheezing, laryngitis, and shortness of breath, skin irritation, erythema, and blistering.

Dichlorodimethyl ether & dibromodimethyl ether (also described as labrynthic substances) - (CH₂Cl)₂O & (CH₂Br)₂O

Both compounds have a suffocating and irritating odour. When they come into contact with moist tissues such as the eyes, throat, and lungs, formaldehyde and hydrochloric acid are produced that can damage these tissues. Severe eye damage can occur at very low levels of exposure, below those detectable by the sense of smell. Both of these agents affect the balance or labrynthic mechanism of the inner era, this means that victims have difficulty balancing and experience dizziness or vertigo.

Dimethyl sulphate [Rationite, D-Stoff] - (CH₃)₂SO₄ 

Dimethyl sulphate is a colourless oily liquid with a slight onion-like odour (although smelling it would represent significant exposure). Dimethyl sulfate is absorbed through the skin, mucous membranes, and gastrointestinal tract, and can cause a fatal delayed respiratory tract reaction. Dimethyl sulphate can produce a lethal concentration in air by evaporation at 20°C. It is highly toxic if inhaled, ingested, or absorbed through the skin. The vapour is extremely irritating and has poor warning properties, meaning it can cause severe damage before being detected.

Symptoms of exposure include: cough, sore throat, shortness of breath, headache. Symptoms may be delayed.  Contact with the skin causes erythema, pain, blistering, skin burns. Eye contact causes redness, pain, burns, permanent blindness. Oral ingestion causes burns in mouth and throat, burning sensation in the throat and chest, abdominal cramps, vomiting, convulsions, shock or collapse.

Long-term or repeated exposure may cause: allergic skin reaction, genetic defects, cancer, damage to liver, kidneys and lungs.

Diphosgene  [DP,Trichloromethylchloroformate, Surpalite, Superpalite, Perstoff] - ClCOOCCl₃

Diphosgene is characterized as a colourless liquid with an odour that is variously described as like newly mown hay, or mouldy hay. It is liquid at normal temperatures but readily produces vapour at toxic concentrations. Similar to phosgene in reactivity; it decomposes slowly in water or moisture to release hydrochloric acid and carbon monoxide. Onset of symptoms is dependent on the concentration but usually rapid. Low-concentration exposure causes chest discomfort and dyspnoea. High-concentration exposure quickly causes acute lung injury with cough, dyspnoea and frothy sputum rapidly followed by respiratory failure, shock and death. Skin contact may cause burns or frostbite, causes lachrymation. It can be absorbed into the body in hazardous amounts by inhalation, ingestion, or contact, it is not readily absorbed through the skin.

Ethyldichloroarsine [Dick, EDED, TL-214; Dichloroethylarsine, Ethyldichloroarsine, dichloro(ethyl)arsane, Ethylarsenic dichloride, Ethylarsonous dichloride] - C₂H₅AsCl₂

A colourless liquid with a fruity biting irritating odor.  Denser than water and vapours are heavier than air. Ethyldichloroarsine is a  powerful irritant that can induce pulmonary edema; It reacts with water to release hydrochloric acid. The liquid produces blisters after an exposure of less than one minute. Bleach may be used to decontaminate ethyldichloroarsine in closed spaces. In open areas, the substance decomposes rapidly without need for decontamination.

Ethylsulfuryl chloride [Sulvanite, ethanesulfonyl chloride, Ethylsulfuryl Chloride, 1-Ethanesulfonyl Chloride] ClSO₃C₂H₅

A pale yellow to light brown or purplish corrosive liquid,  with a strong, pungent odur. It is more dense than water and insoluble in water. Very toxic by ingestion, inhalation, or skin absorption. Ethylsulfuryl Chloride is a moderately persistent and toxic lachrymatory agent. A concentration of as low as 1.00 milligrams per litre is toxic.

Perchlormethylmercaptan [Carbon tetrachlorsulfide, Clairsite, Perchloromethyl mercaptan, Trichloromethane sulfenyl chloride, Trichloromethyl sulfur chloride] - SCCl₄ 

Pale-yellow, oily liquid with an unbearable, acrid odour.  Causes breathing difficulty. Very toxic by inhalation or skin absorption. Exposure to high concentrations may cause pulmonary oedema and death. A severe skin, eye, and respiratory tract irritant. Liquid may cause severe corneal burns if not rinsed out promptly;

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

An pale yellow, oily liquid with an onion-like odor. It is a lung irritant with lachrymatory effects. It is 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.

Phenyldibromoarsine  [Dibromophenylarsine] - C₆H₅AsBr₂

Causes skin and eye blistering. May cause respiratory irritation. Diphenylbromorarsine is known to cause sneezing and coughing, therefore it is regarded as being a sternutator, headache, salivation, and vomiting.

Thiophosgene [Lacrimite, Carbonothioic dichloride, Thiocarbonyl dichloride, Thiocarbonyl chloride] - CSCl₂ -

An easily vapourisable red liquid.  A severe eye irritant. May severely burn skin on contact. Inhalation causes pulmonary oedema.Very toxic by inhalation and by skin absorption. Reacts with water to evolve hydrogen chloride, carbon disulfide, and carbon dioxide. Reaction is slow unless the water is hot. Combustion produces:  phosgene, hydrogen chloride, and sulfur dioxide all of which are toxic. Above 200°C it decomposes to carbon bisulfide (very flammable) and carbon tetrachloride