Wikipedia

CR gas

CRgas ordibenzoxazepine(chemical name dibenz[b,f][1,4]oxazepine, is anincapacitating agentand alachrymatory agent.CR was developed by the BritishMinistry of Defenceas ariot control agentin the late 1950s and early 1960s. A report from thePorton Down laboratoriesdescribed exposure as "like being thrown blindfolded into a bed ofstinging nettles",and it earned the nickname" firegas ".[1][2]

CR gas
Names
Preferred IUPAC name
Dibenzo[b,f][1,4]oxazepine
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.114.990Edit this at Wikidata
UNII
  • InChI=1S/C13H9NO/c1-3-7-12-10(5-1)9-14-11-6-2-4-8-13(11)15-12/h1-9HcheckY
    Key: NPUACKRELIJTFM-UHFFFAOYSA-NcheckY
  • InChI=1/C13H9NO/c1-3-7-12-10(5-1)9-14-11-6-2-4-8-13(11)15-12/h1-9H
    Key: NPUACKRELIJTFM-UHFFFAOYAI
  • N\1=C\c3c(Oc2c/1cccc2)cccc3
Properties
C13H9NO
Molar mass 195.221g·mol−1
Density 1.160±0.10 g/cm3
Melting point 73 °C (163 °F; 346 K)
Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).

In its effects, CR gas is very similar toCS gas(o-chlorobenzylidene malononitrile), but twice as potent, even though there is little structural resemblance between the two. For example, 2 mg of dry CR causes skin redness in 10 min, 5 mg causes burning and erythremia, and20 mg‍—‍strong pain. Water usually amplifies the pain effect of CR on skin. CR aerosols cause irritation at concentrations of 0.2mcg/L, becoming intolerable at 3mcg/L. TheLD50of CR through air inhalation 350 mg·min/L.[3]

Physical properties and deployment

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CR is a pale yellow crystalline solid with a spicy odor. It is slightly soluble in water and does not degrade in it. CR is usually presented as a microparticulate solid, in the form ofsuspensionin apropylene glycol-based liquid. Contrary to its common name, it is not a gas but a solid at room temperature.

The dibenz[b,f][1,4]oxazepinemoietyis present in thetypical antipsychoticdrugloxapine,but, unlike CR,loxapineis not reactive and is not an irritant. CR was first synthesised in 1962.[4]

CR can be delivered either as an aerosol or a solution in water, making it able to be used in water cannons, smoke grenades, or handheld spray cans. For smoke it is usually fired in canisters (LACR) that heat up, producing anaerosolcloud at a steady rate.

Effects

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CR gas is alachrymatory agent(LA), exerting its effects through activation of theTRPA1channel.[5][6][7]Its effects are approximately 6 to 10 times more powerful than those ofCS gas.CR causes intense skin irritation, in particular around moist areas;blepharospasm,causing temporary blindness; and coughing, gasping for breath, and panic. It is capable of causing immediate incapacitation. It is a suspectedcarcinogen.It is toxic, but less so than CS gas, by ingestion and exposure. However, it can be lethal in large quantities. In a poorly ventilated space, an individual may inhale a lethal dose within minutes. Death is caused byasphyxiationandpulmonary edema.

The effect of CR is long-term and persistent. CR can persist on surfaces, especially porous ones, for up to 60 days.

Treatment

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While CS can be decontaminated with a large amount of water, use of water may exacerbate the effects of CR. Skin contaminated with CR gas may become extremely painful in contact with water for up to 48 hours after contamination.[4]

Medical treatment is mostlypalliative.The contaminated clothing has to be removed. The eyes and skin can be washed, the eye pain can be alleviated with medications.[8]

Use

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Egypt

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During the2011 protests against the military government in Egypt,Egyptian security forces allegedly used CR gas in addition to the more commonly used, less debilitating CS gas. One protester described the gas as making him feel "as if your eyes are about to fall out; then you have trouble breathing, and you lose your sight". Egyptians used yeast as a treatment for CR side effects on skin.Mohammed ElBaradeialso confirmed via Twitter that "tear gas with [a]nerve agent"is being used inTahrir Square.[9]

The only gas that has been identified by human rights organizations in protests "is CS tear gas, typically used by police forces to disperse crowds," stated Egyptian journalist Farida Helmy.[10]Egyptian use of CR gas has not been corroborated according toHuman Rights Watch.

France

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People occupying an area in Notre-Dame-des-Landes against an airport project suspect the use of CR gas by French Police and Army in April 2018.[11]

Northern Ireland

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It started being available in police and army supplies, as a water cannon additive and as spray cans, in 1973 and was at least still so in 1981.[1][2]

Republican groups in Northern Ireland have alleged that British Army and Royal Ulster Constabulary units used CR gas against Republican prisoners in the 1970s.[12]Additionally, there are British military documents now declassified and in the public domain held in the records of the UK Ministry of Defence at the National Archives, London, that suggest that the British Army did deploy and use CR gas in Northern Ireland. [13] [14] [15] [16] [17]

Philippines

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CR tear gas was used in suppression of the mutiny in Makati that was led bySen. Antonio Trillanes.The tear gas was fired in the building and all the people in the building including reporters were affected.[citation needed]

South Africa

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In the late 1980s, CR was used in the townships inSouth Africa.It caused some fatalities, in particular among children.[18][19]

Sri Lanka

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The Tamil Tigers of Sri Lanka, an insurgent group in Sri Lanka used CR gas against government forces that were on an offensive to flush and defeat these insurgents during September 2008. Its use hindered the army's progress but ultimately proved ineffective in preventing the army from overrunning their positions. This is one of the first few cases of insurgents using CR gas as aninsurgent weapon.[citation needed]

Turkey

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In theJune 2013 protestagainst the Turkish government, Turkish police allegedly used CR gas on protesters in Istanbul. Doctors in a makeshift first aid post in a Mosque judged it as such.[20][21]

Ukraine

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In Ukraine, CR gas is commonly used by special forces against demonstrators. Gas is packed in a form of spray cans "Cobra 1". For example, gas has been used on a demonstration dedicated to the Ukraine Independence Day (24 August 2011).[22]Also massive gas usage has been documented during demonstrations against Language Law Draft in Kyiv on 3 and 4 July 2012.[23]

See also

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References

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  1. ^abRosenhead, Jonathon (23 Jul 1981)."The technology of riot control".New Scientist.
  2. ^abWright, Steve (6 January 1998)."An Appraisal of Technologies of Political Control".The STOA Programme, Directorate General for Research, European Parliament.Retrieved3 October2015– via pitt.edu.
  3. ^Aleksandroc V.N., Emelyanov V.I. Poisonous Substances: textbook / G.A. Sokolskiy, ed. Moscow. 1990. — 272 с. ISBN 5-203-00341-6.
  4. ^abHigginbo R, Suschitzky H (1962). "Synthesis of Heterocyclic Compounds. 2. Cyclisation of O-Nitrophenyl Oxygen Ethers".J. Chem. Soc.:2367–2370.doi:10.1039/jr9620002367.
  5. ^Gijsen HJ, Berthelot D, Zaja M, Brône B, Geuens I, Mercken M (October 2010). "Analogues of Morphanthridine and the Tear Gas Dibenz[b,f][1,4]oxazepine (CR) as Extremely Potent Activators of the Human Transient Receptor Potential Ankyrin 1 (TRPA1) Channel".J Med Chem.53(19): 7011–7020.doi:10.1021/jm100477n.PMID20806939.
  6. ^Ai, Yong; Song, Fa-Jun; Wang, Shao-Teng; Sun, Qiang; Sun, Ping-Hua (2010)."Molecular Modeling Studies on 11H-Dibenz[b,e]azepine and Dibenz[b,f][1,4]oxazepine Derivatives as Potent Agonists of the Human TRPA1 Receptor".Molecules.15(12): 9364–9379.doi:10.3390/molecules15129364.PMC6259276.PMID21169885.
  7. ^Bessac BF, Sivula M, von Hehn CA, Caceres AI, Escalera J, Jordt SE (April 2009)."Transient receptor potential ankyrin 1 antagonists block the noxious effects of toxic industrial isocyanates and tear gases".FASEB J.23(4): 1102–1114.doi:10.1096/fj.08-117812.PMC2660642.PMID19036859.
  8. ^"Tear Gases: CR - Dibenzoxazepine".Zarc International, Inc. Archived fromthe originalon December 21, 2007.RetrievedNovember 22,2011.
  9. ^"Beskylder egyptiske styrker for massakre"(in Norwegian). NRK.no.RetrievedNovember 22,2011.
  10. ^Farida Helmy, "Chemical Combat", Egypt Today Magazine, January 2012 issue
  11. ^"Zad de Notre-Dame-des-Landes: ce lundi, les gendarmes ont démoli la charpente du Gourbi".Reporterre, le quotidien de l 'écologie(in French).Retrieved2018-04-16.
  12. ^inac.orgArchivedMay 16, 2008, at theWayback Machine
  13. ^TNA DEFE 13/1379"Northern Ireland: use of tear gases; use of CR gas for riot control in Northern Ireland, especially at HM Prison Maze; use of SPAD (Self Protection Aid Device) as a means of delivery. 1973."
  14. ^TNA DEFE 24/967"Northern Ireland: dibenzoxazepine (CR) gas; chemical agent for use in riot control. 1974-77."
  15. ^TNA DEFE 24/1090"Northern Ireland: use of CS and CR gas in countering riots. 1969-77."
  16. ^TNA DEFE 24/1203"Northern Ireland: terrorism; Operation PAGODA; use of CR gas (dibenzoxazepine). 1973-77."This document is still classified, although a record of it is listed in the National Archives (TNA) catalogue.
  17. ^TNA DEFE 24/1903"Development of CR gas: introduction of Self Protection Aid Devices (SPAD) in Northern Ireland; includes arguments for and against their use. 1971-73."
  18. ^Olajos EJ, Salem H (2001)."Riot Control Agents: Pharmacology, Toxicology, Biochemistry and Chemistry".J Appl Toxicol.21(5): 355–391.doi:10.1002/jat.767.PMID11746179.S2CID23368555.
  19. ^"Ireland, Organise! Press Release -Less Lethal Weapons Action Belfast".A-Infos.RetrievedNovember 22,2011.
  20. ^"Erdogan's Police May Be Using Chemical CR Gas on Protesters".The Jewish Press. 2013-06-05.Retrieved2013-09-02.
  21. ^ahmet hasan (3 June 2013)."Dolmabahçe Camii 03.06.2013 00:20"– via YouTube.
  22. ^"Керівництву МВС показали, якими" засобами гігієни "воно озброює" Беркут "- Новини - Український тиждень, Тиждень.ua".26 August 2011.
  23. ^""Беркут" відступив від Українського дому ".
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