Cyanogen chloride is a deadly gas which was historically used in chemical warfare in the First World War. This gas continues to be produced in limited amounts for industrial uses in metalworking and mining. People rarely encounter cyanogen chloride in the modern world, thanks to the banning of chemical warfare and the tight control of hazardous industrial chemicals. It is most commonly seen in industrial accidents, although some research has suggested that terrorist organizations have produced this gas for the purpose of launching attacks.
The chemical formula for this gas is CNCI. It is colorless at room temperature, and while it does have an odor, people usually notice the symptoms of exposure before they smell the slightly sharp, peppery smell of the gas. Cyanogen chloride is a potent irritant and will cause issues like runny nose and eyes, skin irritation, and difficulty breathing when people inhale or touch it.
This gas is what is known as a blood agent, meaning that its toxic effects are caused by absorption into the blood, which can happen when the gas is inhaled or handled. The gas interferes with the body's ability to utilize oxygen, leading to asphyxiation. Other symptoms of cyanogen chloride exposure can include headache, nausea, dizziness, convulsions, paralysis, confusion, and eventual loss of consciousness. It takes only a small amount for the gas to be lethal.
Sodium nitrite, amyl nitrite, and sodium thiosulfate are all antidotes to cyanogen chloride exposure. Because it can take too long to test someone to confirm exposure, an antidote may be administered if exposure is suspected in the interests of protecting health. There are certain settings in which the administration of some antidotes may be contraindicated; for example, sodium nitrite and amyl nitrite are not safe to use in people who are suffering from smoke inhalation.
CK, as it is also known, is heavily restricted. Since it only has limited uses, the manufacture, transport, and use of the gas is tightly regulated. This is designed both to prevent potential stockpiling of the gas, and to ensure that it is used safely, with minimum risks to human health. Manufacture of this and other regulated chemical weapons agents can be grounds for imprisonment and large fines unless someone can demonstrate that the gas was produced for a very good reason, or in an accident. Growing concerns about terrorism in the 21st century made regulation of chemical agents an especially pressing concern for nations worried that people with basic chemical knowledge could present a major security threat.