CS gas (commonly called tear gas), or ortho-chloro-benzal malonitrile, is a usually non-lethal riot control agent. Tear gas is a chemical compound (often generated by a burning process) which, in humans, causes immediate tearing of the eyes, and irritation of the skin and mucous membranes. Tear gas is available in a number of different chemical formulations with effects ranging from mild tearing of the eyes to immediate vomiting and prostration.

Usage

CS is often used in conjunction with OC spray, which is commonly called pepper spray. CS gas and OC sprays are usually used by police to disperse riots and demonstrations. The use of CS gas by the FBI during the siege of the Branch Davidian compound near Waco, Texas, has been the subject of controversy.

As with all riot control agents, their use for chemical warfare is prohibited by the Chemical Weapons Convention.

Tear gas is usually deployed as a burning canister or grenade.

Members of the armed forces of the United States of America and other countries are often exposed to CS during initial training to show the importance of proper wearing of a gas mask. As the agent's presence quickly reveals improper fit or seal of the mask's rubber gaskets against the face, it is sometimes used during training refresher courses or equipment maintenance exercises as well.

Risks to health

Serious risks to health are no surprise when the constituent parts of CS gas are considered. Chlorobenzene , was described by Dr Raymond McClean ^{1 as “a well known industrial poison which could cause damage to the brain, the liver and the kidneys”. Another of it’s components, malonic acid, has caused fatalities in industry.}

CS gas was used in Derry in the area of the Bogside during rioting in the city. In 1969, between the 13th and 14th of August, 1,091 canisters of gas, containing 12.5g of CS and 14 canisters containing 50g of CS were released in the densely populated residential area^{2. On 30 August the Himsworth Enquiry was up set up to investigate the medical effects of it's use in Derry. It's conclusions, viewed in the political context of the time, still pointed towards the necessity of further testing of CS gas before use as a riot control agent. Not long after, the British Army and RUC ceased using CS gas in Derry. It is well accepted that CS gas accentuates illness when inflicted on sufferers of bronchitis, asthma, liver or kidney diseases and epilepsy.}

See also

Police, CN gas, hand grenades

References

• (extracts available online)