Explainer: what is tear gas?
Accusations of the use of tear gas as a weapon of war in Ukraine have put these agents in the spotlight once more
On 1 May, the US Department of State announced that it had imposed new sanctions on the Russian Federation. These were in response to its on going war on Ukraine and use of chemical weapons in the country, including chloropicrin, a chemical belonging to Schedule 3 of the Chemical Weapons Convention, which was used as a tear gas in the first world war. The Department of State said it had ‘made a determination’ under the Chemical and Biological Weapons Control and Warfare Elimination Act of 1991, that Russia had used chloropicrin against Ukrainian forces in violation of the Chemical Weapons Convention.
Tear gas is a generic term for a number of lachrymatory agents, used by law enforcement across the world to control riots and in some countries disrupt public protests. The name describes its effect – it causes severe eye and respiratory pain, causes tears to flow, leading to incapacitation. The most commonly used agent is CS gas, C10H5ClN2 , a cyanocarbon compound 2-chlorobenzalmalononitrile. It is not in fact a gas but a white powder, generally used with a volatile solvent, such as methyl isobutyl ketone. When a cartridge is heated by a pyrotechnic charge it forms an aerosol of white smoke.