CS gas is a widely known chemical irritant, often inaccurately referred to as “tear gas.” It is primarily deployed by law enforcement and military personnel for riot control and crowd dispersion. Classified as a non-lethal incapacitating agent, it temporarily disables individuals through intense sensory irritation. The substance forces compliance by causing immediate, painful, and involuntary physical reactions without intending to cause lasting injury.
The Chemical Identity of CS
The abbreviation “CS” is derived from the surnames of the two American scientists who first synthesized the compound in 1928: Ben Corson and Roger Staughton. The full chemical name for CS is o-Chlorobenzylidene Malononitrile, with the chemical formula \(\text{C}_{10}\text{H}_{5}\text{ClN}_{2}\). Despite its common name, CS is not actually a gas but a white, crystalline solid at room temperature.
It is classified as a lachrymatory agent, a substance that causes tears, and is more potent than other agents in its class. For crowd control, the solid compound is dispersed as a fine-particle aerosol, often generated by burning a canister or dissolving the solid in a solvent. When deployed, these microscopic particles become airborne and attach to moist surfaces, allowing the irritant to take effect.
Physiological Effects on the Body
Upon exposure, the effects of CS gas are nearly immediate, typically beginning within 20 to 60 seconds. The substance works by binding to specific pain receptors, known as nociceptors, found in the mucous membranes of the eyes, nose, mouth, and respiratory tract. CS specifically targets and activates the Transient Receptor Potential Ankyrin 1 (TRPA1) ion channel, triggering an intense sensation of pain and burning.
In the eyes, this causes an immediate and profuse flow of tears, involuntary closing of the eyelids (blepharospasm), and temporary vision impairment. The respiratory system reacts with a burning sensation in the throat and nose, chest tightness, coughing, and difficulty breathing. Skin contact, particularly with damp or sweaty skin, causes redness, stinging, and a painful burning sensation.
These acute symptoms can include disorientation, dizziness, and excessive salivation, making it impossible for a person to function normally. While the symptoms are severe, they are temporary and subside quickly once the individual is removed from the contaminated environment. Those with pre-existing respiratory conditions, such as asthma, may experience more severe or complicated reactions.
Immediate Decontamination and Relief
The first step for anyone exposed to CS gas is to immediately move out of the contaminated area and into fresh air. Symptoms should spontaneously resolve within 15 to 30 minutes after exposure ceases.
Contaminated outer clothing should be removed as quickly as possible to prevent continued off-gassing and re-exposure, ideally by cutting it off rather than pulling it over the head. The clothing should be sealed in a plastic bag for disposal to prevent the spread of the agent.
Any affected skin areas should be blotted and wiped with a dry, absorbent material to remove the solid particles. Avoid rubbing the skin or eyes, as this can grind the crystalline particles deeper into the tissue and worsen the irritation. Flushing the eyes and skin with copious amounts of cool water can help, but avoid using hot water because it can open the pores and increase the absorption of the irritant.