{{Short description|Chemical weapon}}
{{other uses}} {{Use dmy dates|date=December 2019}} thumb|upright|Tear gas in use in France 2007 thumb|An exploded tear gas canister airborne in Greece [[File:1.21.26 Green Gas Canister Ben.webm|thumb|right|A tear gas canister in Minneapolis during Operation Metro Surge]]
'''Tear gas''', also known as a '''lachrymatory agent''' or '''lachrymator''' ({{ety|la|lacrima|tear}}), sometimes colloquially known as "'''mace'''" after the early commercial self-defense spray, is a chemical weapon that stimulates the nerves of the lacrimal gland in the eye to produce tears. In addition, it can cause severe eye and respiratory pain, skin irritation, bleeding, and blindness. Common lachrymators both currently and formerly used as tear gas include pepper spray (OC gas), PAVA spray (nonivamide), CS gas, CR gas, CN gas (phenacyl chloride), bromoacetone, xylyl bromide, chloropicrin (PS gas) and Mace (a branded mixture).
While lachrymatory agents are commonly deployed for riot control by law enforcement and military personnel, their use in warfare is prohibited by various international treaties.<ref group=NB name=GenevaProtocol>E.g. the Geneva Protocol of 1925 prohibited the use of "asphyxiating gas, or any other kind of gas, liquids, substances or similar materials".</ref> During World War I, increasingly toxic and deadly lachrymatory agents were used.
The short and long-term effects of tear gas are not well studied. The published peer-reviewed literature consists of lower quality evidence that do not establish causality.<ref name=":0" /> Exposure to tear gas agents may produce numerous short-term and long-term health effects, including development of respiratory illnesses, severe eye injuries and diseases (such as traumatic optic neuropathy, keratitis, glaucoma, and cataracts), dermatitis, damage of cardiovascular and gastrointestinal systems, and death, especially in cases with exposure to high concentrations of tear gas or application of the tear gases in enclosed spaces.<ref name="Rothenberg 2016" />
==Effects == [[Image:CS gas.svg|thumb|144px|2-chlorobenzalmalononitrile is the active agent in CS gas.]]
Tear gas generally consists of aerosolized solid or liquid compounds (bromoacetone or xylyl bromide), not gas.<ref name="Rothenberg 2016">{{cite journal | vauthors = Rothenberg C, Achanta S, Svendsen ER, Jordt SE | title = Tear gas: an epidemiological and mechanistic reassessment | journal = Annals of the New York Academy of Sciences | volume = 1378 | issue = 1 | pages = 96–107 | date = August 2016 | pmid = 27391380 | pmc = 5096012 | doi = 10.1111/nyas.13141 | bibcode = 2016NYASA1378...96R }}</ref> Tear gas works by irritating mucous membranes in the eyes, nose, mouth and lungs. It causes crying, coughing, difficulty breathing, pain in the eyes, and temporary blindness.
With CS gas, symptoms of irritation typically appear after 20 to 60 seconds of exposure<ref name="Schep">{{cite journal | vauthors = Schep LJ, Slaughter RJ, McBride DI | title = Riot control agents: the tear gases CN, CS and OC-a medical review | journal = Journal of the Royal Army Medical Corps | volume = 161 | issue = 2 | pages = 94–99 | date = June 2015 | pmid = 24379300 | doi = 10.1136/jramc-2013-000165 | doi-access = free }}</ref> and commonly resolve within 30 minutes of leaving the area.
===Risks===
[[File:Tear gas aftermath.jpg|thumb|The aftermath of exposure to tear gas during protests in Oakland, California]] As with all non-lethal or less-lethal weapons, there is a risk of serious permanent injury or death when tear gas is used.<ref name=":0">{{cite journal |vauthors=Torgrimson-Ojerio BN, Mularski KS, Peyton MR, Keast EM, Hassan A, Ivlev I |title=Health issues and healthcare utilization among adults who reported exposure to tear gas during 2020 Portland (OR) protests: a cross-sectional survey |journal=BMC Public Health |volume=21 |issue=1 |article-number=803 |date=April 2021 |pmid=33902512 |pmc=8074355 |doi=10.1186/s12889-021-10859-w |doi-access=free}}</ref><ref>{{cite web |title=Possible lethal effects of CS tear gas on Branch Davidians during the FBI raid on the Mount Carmel compound near Waco, Texas |author=Heinrich U |work=Prepared for The Office of Special Counsel John C. Danforth |date=September 2000 |url=http://www.veritagiustizia.it/docs/gas_cs/CS_Effects_Waco.pdf |archive-url=https://web.archive.org/web/20040830001830/http://www.veritagiustizia.it/docs/gas_cs/CS_Effects_Waco.pdf |archive-date=30 August 2004 }}</ref><ref name="Hu-JAMA-free">{{cite journal | vauthors = Hu H, Fine J, Epstein P, Kelsey K, Reynolds P, Walker B | title = Tear gas – harassing agent or toxic chemical weapon? | journal = JAMA | volume = 262 | issue = 5 | pages = 660–663 | date = August 1989 | pmid = 2501523 | doi = 10.1001/jama.1989.03430050076030 | url = http://desastres.usac.edu.gt/documentos/pdf/eng/doc8080/doc8080-contenido.pdf | archive-url = https://web.archive.org/web/20131029183849/http://desastres.usac.edu.gt/documentos/pdf/eng/doc8080/doc8080-contenido.pdf | archive-date = 29 October 2013 }}</ref><ref name="Rothenberg 2016" /> Risks include from being hit by tear gas cartridges that may cause severe bruising, loss of eyesight, or skull fracture, resulting in immediate death.<ref name="pmid14550613">{{cite journal | vauthors = Clarot F, Vaz E, Papin F, Clin B, Vicomte C, Proust B | title = Lethal head injury due to tear-gas cartridge gunshots | journal = Forensic Science International | volume = 137 | issue = 1 | pages = 45–51 | date = October 2003 | pmid = 14550613 | doi = 10.1016/S0379-0738(03)00282-2 }}</ref> A case of serious vascular injury from tear gas shells occurred in Iran, with high rates of associated nerve injury (44%) and amputation (17%),<ref name="Wani 2011">{{cite journal | vauthors = Wani ML, Ahangar AG, Lone GN, Singh S, Dar AM, Bhat MA, Ashraf HZ, Irshad I | display-authors = 6 | title = Vascular injuries caused by tear gas shells: surgical challenge and outcome | journal = Iranian Journal of Medical Sciences | volume = 36 | issue = 1 | pages = 14–17 | date = March 2011 | pmid = 23365472 | pmc = 3559117 }}</ref> and instances of head injuries in young people.<ref name="Wani 2010">{{cite journal | vauthors = Wani AA, Zargar J, Ramzan AU, Malik NK, Qayoom A, Kirmani AR, Nizami FA, Wani MA | display-authors = 6 | title = Head injury caused by tear gas cartridge in teenage population | journal = Pediatric Neurosurgery | volume = 46 | issue = 1 | pages = 25–28 | year = 2010 | pmid = 20453560 | doi = 10.1159/000314054 | s2cid = 27737407 }}</ref> Novel findings suggest that menstrual changes are one of the most commonly reported health issues in women.<ref name=":0" />
thumb|An injury from a direct hit by a tear gas canister While the medical consequences of the gases are typically limited to minor skin inflammation, delayed complications are also possible. People with pre-existing respiratory conditions such as asthma are particularly at risk. They are likely to need medical attention<ref name="Schep" /> and may sometimes require hospitalization or even ventilation support.<ref name="Carron2009">{{cite journal | vauthors = Carron PN, Yersin B | title = Management of the effects of exposure to tear gas | journal = BMJ | volume = 338 | article-number = b2283 | date = June 2009 | pmid = 19542106 | doi = 10.1136/bmj.b2283 | s2cid = 7870564 | url = http://www.bmj.com/content/338/bmj.b2283?view=long&pmid=19542106 | url-access = subscription }}</ref>
Skin exposure to CS gas may cause chemical burns<ref name="pmid10353039">{{cite journal | vauthors = Worthington E, Nee PA | title = CS exposure – clinical effects and management | journal = Journal of Accident & Emergency Medicine | volume = 16 | issue = 3 | pages = 168–170 | date = May 1999 | pmid = 10353039 | pmc = 1343325 | doi = 10.1136/emj.16.3.168 }}</ref><ref name=":0" /> or induce allergic contact dermatitis.<ref name="Schep" /><ref name="Smith2002">{{cite journal|vauthors=Smith J, Greaves I|title=The use of chemical incapacitant pepper spray laws and restrictions by State. |journal=The Journal of Trauma|volume=52|issue=3|pages=595–600|date=March 2002|pmid=11901348|doi=10.1097/00005373-200203000-00036|url=https://uguardsecurityproducts.com/pepper-spray-sprays-by-state/ |url-access=subscription}}</ref> When people are hit at close range or are severely exposed, eye injuries involving scarring of the cornea can lead to a permanent loss in visual acuity.<ref name="pmid1108587">{{cite journal | vauthors = Oksala A, Salminen L | title = Eye injuries caused by tear-gas hand weapons | journal = Acta Ophthalmologica | volume = 53 | issue = 6 | pages = 908–913 | date = December 1975 | pmid = 1108587 | doi = 10.1111/j.1755-3768.1975.tb00410.x | s2cid = 46409336 }}</ref> Frequent or high levels of exposure carry increased risks of respiratory illness.<ref name="Rothenberg 2016" />
Venezuelan chemist Mónica Kräuter studied thousands of tear gas canisters fired by Venezuelan authorities since 2014. She concluded that the majority of canisters used the main component CS gas, and that 72% of the tear gas used was expired. She noted that expired tear gas "breaks down into cyanide oxide, phosgenes and nitrogens that are extremely dangerous".<ref>{{cite news |date=8 April 2017 |title=Bombas lacrimógenas que usa el gobierno están vencidas y emanan cianuro (+ recomendaciones) |url=https://www.lapatilla.com/site/2017/04/08/bombas-lacrimogenas-que-usa-el-gobierno-estan-vencidas-y-emanan-cianuro-recomendaciones/ |archive-url=https://web.archive.org/web/20170410051345/https://www.lapatilla.com/site/2017/04/08/bombas-lacrimogenas-que-usa-el-gobierno-estan-vencidas-y-emanan-cianuro-recomendaciones/ |archive-date=10 April 2017 |access-date=9 April 2017 |work=La Patilla |language=es-ES}}</ref>
In the 2019–20 Chilean protests, people have had complete and permanent loss of vision in one or both eyes as result of the impact of tear gas grenades.<ref name=Mujer36INDH>{{Cite news|title=INDH se querella por homicidio frustrado contra Carabineros en favor de trabajadora que habría perdido visión de ambos ojos|url=https://www.indh.cl/indh-se-querella-por-homicidio-frustrado-contra-carabineros-en-favor-de-trabajadora-que-habria-perdido-vision-de-ambos-ojos/|date=November 27, 2020|access-date=June 29, 2020|work=Instituto Nacional de Derechos Humanos|language=es}}</ref><ref name=LastraINDH>{{Cite news|title=INDH presenta querella por joven que perdió un ojo por lacrimógena en año nuevo en Plaza Italia|url=https://www.indh.cl/indh-presenta-querella-por-joven-que-perdio-un-ojo-por-lacrimogena-en-ano-nuevo-en-plaza-italia/|date=January 8, 2020|access-date=June 29, 2020|work=Instituto Nacional de Derechos Humanos|language=es}}</ref><ref name=OrellanaINDH>{{Cite news|title=INDH se querella por lesión a profesor que perdió un ojo en Valparaíso|url=https://www.indh.cl/indh-se-querella-por-lesion-a-profesor-que-perdio-la-vista-en-un-ojo-en-valparaiso/|date=January 4, 2020|access-date=June 29, 2020|work=Instituto Nacional de Derechos Humanos|language=es}}</ref>
The majority (2,116; 93.8%) of protestors exposed to tear gas during the 2020 protests in Portland, Oregon, reported physical (2,114; 93.7%) or psychological (1,635; 72.4%) health issues experienced immediately after (2,105; 93.3%) or days following (1,944; 86.1%) the exposure. The majority (1,233; 54.6%) of respondents exposed to tear gas received or planned to seek medical or mental healthcare for their tear gas-related health issues.<ref name=":0" /> Health issues associated with exposure to tear gas often require medical attention.<ref name=":0" />
===Site of action===
TRPA1 ion channels expressed on nociceptors have been implicated as the site of action for CS gas, CR gas, CN gas (phenacyl chloride), chloropicrin and bromoacetone in rodent models.<ref>{{cite journal | vauthors = Bessac BF, Sivula M, von Hehn CA, Caceres AI, Escalera J, Jordt SE | title = Transient receptor potential ankyrin 1 antagonists block the noxious effects of toxic industrial isocyanates and tear gases | journal = FASEB Journal | volume = 23 | issue = 4 | pages = 1102–1114 | date = April 2009 | pmid = 19036859 | pmc = 2660642 | doi = 10.1096/fj.08-117812 | doi-access = free }}</ref><ref>{{cite journal | vauthors = Brône B, Peeters PJ, Marrannes R, Mercken M, Nuydens R, Meert T, Gijsen HJ | title = Tear gasses CN, CR, and CS are potent activators of the human TRPA1 receptor | journal = Toxicology and Applied Pharmacology | volume = 231 | issue = 2 | pages = 150–156 | date = September 2008 | pmid = 18501939 | doi = 10.1016/j.taap.2008.04.005 | bibcode = 2008ToxAP.231..150B }}</ref>
==Uses==
===Warfare=== {{see also|Xylyl bromide#Use as a weapon|Chemical weapons in World War I}}
During World War I, forms of tear gas were used in combat and tear gas was the most common form of chemical weapon used. None of the belligerents believed that the use of irritant gases violated the Hague Convention of 1899 which prohibited the use of "poison or poisoned weapons" in warfare. Grenades with the lacrimatory agent ethyl bromoacetate were the first chemical weapon used in World War I. It first was used in August 1914 by the French, whose police had previously used it domestically starting in 1912; followed by the Germans deploying the lung irritant dianisidine chlorosulphonate they called "Nerst Ni-Shrapnel" or "ni-shells" (derived from the word for sneezing powder) against British and Indian troops in October, and the lacrimatory irritant xylyl bromide against the Russians in January of 1915. Alone, these riot control agents' use was small scale and ineffective and over shadowed by the stronger chemical weapons that were introduced later in 1915. Tear gas continued to be used until the end of the war.<ref name=":3">{{Cite book |last=Tuorinksi |first=D. Shirley |title=Medical Aspects of Chemical Warfare |publisher=Office of the Surgeon General |year=2008 |location=Washington, DC |pages=12–22 |language=English}}</ref><ref>{{Cite book |last=Grant |first=R. G. |title=World War I: the definitive visual history: from Sarajevo to Versailles |date=2024 |publisher=DK Publishing |others=DK Publishing, Inc, Smithsonian Institution |isbn=978-0-7440-9851-8 |edition=Revised |location=New York}}</ref>
Although the French were the first to deploy tear gas in war, an American schoolteacher first proposed using artillery shells filled with chlorine gas in 1862.<ref name=":3" /> The US Chemical Warfare Service developed tear gas grenades for use in riot control in 1919.<ref name=":3" /><ref name="Jones_1978">{{cite journal |author=Jones DP |title=From Military to Civilian Technology: The Introduction of Tear Gas for Civil Riot Control |journal=Technology and Culture |date=April 1978 |volume=19 |issue=2 |pages=151–168 |jstor=3103718 |doi=10.2307/3103718|s2cid=113339773 }}</ref>
Use of tear gas in interstate warfare, as with all other chemical weapons, was prohibited by the Geneva Protocol of 1925: it prohibited the use of "asphyxiating gas, or any other kind of gas, liquids, substances or similar materials", a treaty that most states have signed. Police and civilian self-defense use is not banned in the same manner. The United States adopted the protocol under the stipulation that it did not apply to tear gas use in warfare as the agents were nonlethal and used domestically, and did not ratify the protocol until 1975 following controversy over its use in the Vietnam War.<ref>{{Cite journal |last1=Baxter |first1=R. R. |last2=Buergenthal |first2=Thomas |date=October 1970 |title=Legal Aspects of the Geneva Protocol of 1925 |url=https://doi.org/10.2307/2198921 |journal=American Journal of International Law |volume=64 |issue=5 |pages=853–879 |doi=10.2307/2198921 |jstor=2198921 |issn=0002-9300|url-access=subscription }}</ref><ref>{{cite web | url = https://ihl-databases.icrc.org/customary-ihl/eng/docs/v2_cha_chapter24_rule75 |access-date = 7 July 2020 | work = ihl-databases.icrc.org/ | title = Practice Relating to Rule 75. Riot Control Agent | publisher=IHL Database }}</ref>
Tear gas was used in combat by Italy in the Second Italo-Ethiopian War, by Japan in the Second Sino-Japanese War, by Iraq in the Iran–Iraq War, by Spain in the Rif War, by the United States in the Vietnam War, and by Israel in the Israel–Palestine conflict.<ref>[https://www.theatlantic.com/international/archive/2014/08/100-years-of-tear-gas/378632/ 100 Years of Tear Gas], ''The Atlantic'', August 16, 2014</ref><ref>{{Cite news|url=https://www.haaretz.com/israel-news/2021-09-19/ty-article/.premium/israeli-soldiers-attack-activists-palestinians-bringing-water-to-west-bank-village/0000017f-ee07-d4a6-af7f-fec7f1b00000|title=Israeli Soldiers Assault Activists, Palestinians Bringing Water to West Bank Village|newspaper=Haaretz}}</ref>
Tear gas exposure is an element of military training programs, typically as a means of improving trainees' tolerance to tear gas and encouraging confidence in the ability of their issued protective equipment to prevent chemical weapons exposure.<ref>{{cite web | url = https://www.tecom.marines.mil/News/News-Article-Display/Article/528466/co-g-recruits-use-new-gas-mask-in-confidence-chamber/ | access-date = 25 October 2019 | work = tecom.marines.mil | title = Co. G recruits use new gas mask in confidence chamber | publisher = Marine Corps Websites}}</ref><ref>{{cite web | url = https://www.mcrdsd.marines.mil/News/Article/560025/recruits-feel-effects-of-confidence-chamber/ | access-date = 25 October 2019 | work = mcrdsd.marines.mil | title = Recruits feel effects of Confidence Chamber | publisher = Marine Corps Websites}}</ref><ref>{{cite news|title=MoD confirms army CS gas investigation|url=http://www.politics.co.uk/news/2006/05/13/mod-confirms-army-cs-gas-investigation|access-date=6 January 2013|newspaper=Politics.co.uk|date=13 May 2006|archive-url=https://web.archive.org/web/20131009230624/http://politics.co.uk/news/2006/05/13/mod-confirms-army-cs-gas-investigation|archive-date=9 October 2013}}</ref>
===Riot control===
Certain lachrymatory agents, most notably tear gas, are often used by police to force compliance.<ref name="Hu-JAMA-free"/> In some countries (e.g., Finland, Australia, and United States), another common substance is mace. The self-defense weapon form of mace is based on pepper spray which comes in small spray cans. Versions including CS are manufactured for police use.<ref name="Mace">{{cite web|title=Mace pepper spray|url=http://www.mace.com/take-down-law-enforcement-pepper-sprays.html|archive-url=https://web.archive.org/web/20130805002453/http://www.mace.com/take-down-law-enforcement-pepper-sprays.html|archive-date=August 5, 2013|access-date=21 February 2014|publisher=Mace (manufacturer)}}</ref> Xylyl bromide, CN and CS are the oldest of these agents. CS gas is the most widely used. CN has the most recorded toxicity.<ref name="Schep" />
Typical manufacturer warnings on tear gas cartridges state "Danger: Do not fire directly at person(s). Severe injury or death may result."<ref name="url_CNN.com">{{cite web |url=http://edition.cnn.com/2011/WORLD/africa/01/28/egypt.us.tear.gas/index.html |archive-url=https://web.archive.org/web/20110129015707/http://edition.cnn.com/2011/WORLD/africa/01/28/egypt.us.tear.gas/index.html |archive-date=29 January 2011 |title=Controversial tear gas canisters made in the USA |author=Smith E |date=28 January 2011 |work=Africa |publisher=CNN}}</ref> Tear gas guns do not have a manual setting to adjust the range of fire. The only way to adjust the projectile's range is to aim towards the ground at the correct angle. Incorrect aim will send the capsules away from the targets, causing risk for non-targets instead.<ref>Turkish Doctors' Association, 16 June 2013, [https://web.archive.org/web/20130616153535/http://www.ttb.org.tr/index.php/Haberler/cagri-3870.html Türk Tabipleri Birliği'nden Acil Çağri!]</ref>
{{center| <gallery widths="200px" heights="200px"> File:Hong Kong Umbrella Revolution-HD.webm|thumbtime=2:00|Tear gas fired to disperse protesters outside government headquarters during 2014 Hong Kong Protests in September 2014 File:Tear gas used against protest in Altamira, Caracas; and distressed students in front of police line.jpg|Tear gas being used against opposition protesters during the 2014 Venezuelan protests File:Tear gas grenade returned to soldiers using sling.jpg|A protester uses a sling to send a tear gas grenade back towards Israeli soldiers during a Palestinian weekly protest in Ni'lin, July 2014. File:Thai Riot Police Dindang Protest.JPG|Riot Police fire tear gas to anti-government protesters during Din Daeng Protests in August 2021. File: Gregory Bovino throws tear gas at protesters on January 21 (1.21.26 Bovino Throws Gas 2.33 PM Ben) (2026-01-21).webm|Gregory Bovino throws tear gas during Operation Metro Surge, Minneapolis, 2026. File:DSF3347-Tear-gas.jpg|Tear gas during the repression of the protest against the El Khomri law (labour law) in Paris, France, 2016. </gallery> }}
===Counter-measures=== thumb|right|People using umbrellas to defend from tear gas canisters and less-than-lethal munitions A variety of protective equipment may be used, including gas masks and respirators. In riot control situations, protesters sometimes use equipment, aside from simple rags or clothing over the mouth, such as swimming goggles and adapted water bottles, and covering as much skin as possible.<ref name="urlLOCAL - Gezi park protesters bring handmade masks to counter police tear-gas rampage">{{cite web |url=http://www.hurriyetdailynews.com/gezi-park-protesters-bring-handmade-masks-to-counter-police-tear-gas-rampage.aspx?pageID=238&nID=47935&NewsCatID=341 |title=Gezi park protesters bring handmade masks to counter police tear-gas rampage |work=Hürriyet Daily News|date=31 May 2013 }}</ref><ref name="newssafety.org">{{Cite web |title=Protecting yourself from tear gas: INSI |url=https://newssafety.org/safety/advisories/protecting-yourself-from-tear-gas/ |access-date=2020-11-28 |website=newssafety.org |archive-date=25 July 2021 |archive-url=https://web.archive.org/web/20210725165145/https://newssafety.org/safety/advisories/protecting-yourself-from-tear-gas/ }}</ref><ref name=":1">{{Cite web |last=Livingston |first=Mercey |title=Here's what to do if you get exposed to tear gas |url=https://www.cnet.com/health/tear-gas-protests-how-to-protect-yourself-what-to-do-if-you-are-exposed/ |access-date=2020-11-28 |website=CNET |date=2 June 2020 |language=en}}</ref>
Activists in United States, the Czech Republic, Venezuela and Turkey have used antacid solutions such as Maalox diluted with water to repel effects of tear gas attacks,<ref>{{cite web |url=http://www.rawstory.com/rs/2011/10/29/maalox-and-water-solution-used-as-anti-tear-gas-remedy-by-protesters/ |title='Maalox'-and-water solution used as anti-tear gas remedy by protesters |first=David |last=Ferguson |name-list-style=vanc |date=28 September 2011 |website=Raw Story |access-date=4 June 2013 |archive-date=23 August 2014 |archive-url=https://web.archive.org/web/20140823020353/http://www.rawstory.com/rs/2011/10/29/maalox-and-water-solution-used-as-anti-tear-gas-remedy-by-protesters/ }}</ref><ref>{{cite web |url=http://www.starhawk.org/activism/trainer-resources/teargas.html |title=Medical information from Prague 2000 |archive-url=https://web.archive.org/web/20141018221605/http://www.starhawk.org/activism/trainer-resources/teargas.html |archive-date=18 October 2014 }}</ref><ref>{{cite web |url=http://occupywallst.org/article/instanbul-is-burning/ |title=Istanbul is burning |author=Ece Temelkuran |publisher=Occupy Wall Street |date=3 June 2013}}</ref> with Venezuelan chemist Mónica Kräuter recommending the usage of diluted antacids as well as baking soda.<ref name="Tururu">{{Cite news|date=26 May 2017|title=Prof USB Mónica Kräuter, Cómo reaccionar ante las bombas lacrimógenas|language=es-ES|work=Tururutururu|url=http://tururutururu.com/prof-usb-monica-krauter-como-reaccionar-ante-las-bombas-lacrimogenas/|access-date=1 November 2017|archive-url=https://web.archive.org/web/20171107025513/http://tururutururu.com/prof-usb-monica-krauter-como-reaccionar-ante-las-bombas-lacrimogenas/|archive-date=November 7, 2017}}</ref> There have been reports of these antacids being helpful for tear gas,<ref name="Carron 2009" /> and for capsaicin-induced skin pain.<ref name="Kim-Katz 2010">{{cite journal | vauthors = Kim-Katz SY, Anderson IB, Kearney TE, MacDougall C, Hudmon KS, Blanc PD | title = Topical antacid therapy for capsaicin-induced dermal pain: a poison center telephone-directed study | journal = The American Journal of Emergency Medicine | volume = 28 | issue = 5 | pages = 596–602 | date = June 2010 | pmid = 20579556 | doi = 10.1016/j.ajem.2009.02.007 | url = https://zenodo.org/record/894912 }}</ref>
thumb|right|250x250px|thumbtime=00:10|Protestors in Hong Kong using traffic cones to put out tear gas canisters During the 2019 Hong Kong protests, frontline protesters became adept at extinguishing tear gas: they formed special teams that sprang into action as soon as it was fired. These individuals generally wore protective clothing, including heat-proof gloves, or covered their arms and legs with cling film to prevent the painful skin irritation. Canisters were sometimes picked up and lobbed back at police or extinguished straight away with water, or neutralized using objects such as traffic cones.<ref name="tear gas creativity"/>
They shared information about models of 3M respirator filters which had been found to be most effective against tear gas, and where those models could be purchased. Other volunteers carried saline solutions to rinse the eyes of those affected.<ref name="tear gas creativity">{{cite news|date=9 August 2019|title=Hong Kongers get creative with traffic cones and kitchenware to fight tear gas|work=Japan Times|url=https://www.japantimes.co.jp/news/2019/08/09/asia-pacific/hong-kongers-get-creative-traffic-cones-kitchenware-fight-tear-gas/|access-date=27 October 2019|archive-url=https://web.archive.org/web/20191107080957/https://www.japantimes.co.jp/news/2019/08/09/asia-pacific/hong-kongers-get-creative-traffic-cones-kitchenware-fight-tear-gas/|archive-date=7 November 2019}}</ref> Similarly, Chilean protesters of Primera Línea had specialized individuals collecting and extinguishing the tear gas grenades. Others acted as tear gas medics, and another group, the "shield-bearers," protected the protesters from the direct physical impact of the grenades.<ref name=CiperMag>{{Cite news|title=Retrato de un clan de la Primera Línea|url=https://ciperchile.cl/2020/01/06/retrato-de-un-clan-de-la-primera-linea/|last=Claude|first=Magdalena|date=January 6, 2020|access-date=March 6, 2020|work=CIPER Chile|language=es}}</ref>
==Treatment== [[File:Opposition medic 2014 Venezuelan protests..jpg|upright=1.1591|thumb|A paramedic tending to an opposition protester during the 2014 Venezuelan protests]] [[File:Fabiola_Campillai_2021.jpg|250px|thumb|Fabiola Campillai, a Chilean woman left blind in both eyes by a direct hit of a tear-gas grenade in her face]]
There is no specific antidote to common tear gases.<ref name="Schep" /><ref name="Kim 2016">{{cite journal | vauthors = Kim YJ, Payal AR, Daly MK | title = Effects of tear gases on the eye | journal = Survey of Ophthalmology | volume = 61 | issue = 4 | pages = 434–442 |year = 2016 | pmid = 26808721 | doi = 10.1016/j.survophthal.2016.01.002 }}</ref> At the first sign of exposure or potential exposure, masks are applied when available. People are removed from the affected area when possible.<ref name=":2">{{Cite web |title=Riot-Control Chemical Agents - Injuries; Poisoning |url=https://www.msdmanuals.com/professional/injuries-poisoning/mass-casualty-weapons/riot-control-chemical-agents |access-date=2022-10-04 |website=MSD Manual Professional Edition |language=en}}</ref><ref name=Yeung>{{cite journal | vauthors = Yeung MF, Tang WY | title = Clinicopathological effects of pepper (oleoresin capsicum) spray | journal = Hong Kong Medical Journal | volume = 21 | issue = 6 | pages = 542–552 | date = December 2015 | pmid = 26554271 | doi = 10.12809/hkmj154691 | doi-access = free }}</ref> Immediate removal of contact lenses has also been recommended, as they can retain particles.<ref name=Yeung /><ref name="Kim 2016" />
Decontamination is by physical or mechanical removal (brushing, washing, rinsing) of solid or liquid agents. Water may transiently exacerbate the pain caused by CS gas and pepper spray but is still effective. Fat-containing oils or soaps may be more effective against pepper spray. Eyes are decontaminated by copious flushing with sterile water or saline or (with OC) open-eye exposure to wind from a fan. Referral to an ophthalmologist is needed if slit-lamp examination shows impaction of solid particles of agent.<ref name="Schep" /><ref name=":2" /><ref name="Chau">{{cite journal | vauthors = Chau JP, Lee DT, Lo SH | title = A systematic review of methods of eye irrigation for adults and children with ocular chemical burns | journal = Worldviews on Evidence-Based Nursing | volume = 9 | issue = 3 | pages = 129–138 | date = August 2012 | pmid = 21649853 | doi = 10.1111/j.1741-6787.2011.00220.x | s2cid = 205874180 }}</ref>
Blowing the nose to get rid of the chemicals is recommended, as is avoiding rubbing of the eyes.<ref name=":1" /> There are reports that water may increase pain from CS gas, but the balance of limited evidence currently suggests water or saline are the best options.<ref name="Kim 2016" /><ref name="Carron 2009">{{cite journal | vauthors = Carron PN, Yersin B | title = Management of the effects of exposure to tear gas | journal = BMJ | volume = 338 | article-number = b2283 | date = June 2009 | pmid = 19542106 | doi = 10.1136/bmj.b2283 | s2cid = 7870564 }}</ref><ref name="Brvar 2015">{{cite journal | vauthors = Brvar M | title = Chlorobenzylidene malononitrile tear gas exposure: Rinsing with amphoteric, hypertonic, and chelating solution | journal = Human & Experimental Toxicology | volume = 35 | issue = 2 | pages = 213–218 | date = February 2016 | pmid = 25805600 | doi = 10.1177/0960327115578866 | bibcode = 2016HETox..35..213B | s2cid = 40353355 | doi-access = free }}</ref> Some evidence suggests that Diphoterine, a hypertonic amphoteric salt solution, a first aid product for chemical splashes, may help with ocular burns or chemicals in the eye.<ref name="Chau" /><ref name="Viala">{{cite journal | vauthors = Viala B, Blomet J, Mathieu L, Hall AH | title = Prevention of CS 'tear gas' eye and skin effects and active decontamination with Diphoterine: preliminary studies in 5 French Gendarmes | journal = The Journal of Emergency Medicine | volume = 29 | issue = 1 | pages = 5–8 | date = July 2005 | pmid = 15961000 | doi = 10.1016/j.jemermed.2005.01.002 }}</ref>
Bathing and washing the body vigorously with soap and water can remove particles that adhere to the skin. Clothes, shoes and accessories that come into contact with vapors must be washed well, since all untreated particles can remain active for up to a week.<ref name=LPteargas>{{cite news|title=Who, What, Why: How dangerous is tear gas?|url=https://www.bbc.com/news/magazine-15887186/|access-date=31 May 2017|publisher=BBC|date=25 November 2011}}</ref> Some advocate using fans or hair dryers to evaporate the spray, but this has not been shown to be better than washing out the eyes and it may spread contamination.<ref name="Kim 2016" />
Anticholinergics can work like some antihistamines as they reduce lacrymation and decrease salivation, acting as an antisialagogue, and for overall nose discomfort as they are used to treat allergic reactions in the nose (e.g., itching, runny nose, and sneezing).{{Citation needed|date=June 2020}}
Oral analgesics may help relieve eye pain.<ref name="Kim 2016" />
Most effects resulting from riot-control agents are transient and do not require treatment beyond decontamination. Most patients do not need observation beyond 4 hours. Patients should be instructed to return if they develop effects such as blistering or delayed-onset shortness of breath.<ref name=":2" />
=== Home remedies === Vinegar, petroleum jelly, milk and lemon juice solutions have also been used by activists.<ref name="AFP-NDTV">{{cite web |last=Agence France-Press |title=Tear gas and lemon juice in the battle for Taksim Square |url=http://www.ndtv.com/article/world/tear-gas-and-lemon-juice-in-the-battle-for-taksim-square-378328 |publisher=NDTV |access-date=23 June 2013}}</ref><ref>{{cite news |url=http://www.post-gazette.com/stories/local/neighborhoods-city/turks-in-pittsburgh-concerned-for-nation-692899/ |title=Turks in Pittsburgh concerned for their nation |date=24 June 2013 | first = Megan | last = Doyle | name-list-style = vanc |newspaper=Pittsburgh Post-Gazette}}</ref><ref>{{cite news |url=https://www.nytimes.com/2013/06/16/world/europe/protesters-in-turkey.html |title=Police Storm Park in Istanbul, Setting Off a Night of Chaos |date=15 June 2013 | first = Tim | last = Arango | name-list-style = vanc |newspaper=The New York Times}}</ref><ref>{{cite news|last=Hughes|first=Gareth|date=25 June 2013|title=Denbigh man tear gassed|newspaper=The Free Press|url=http://www.denbighshirefreepress.co.uk/news/123984/denbigh-man-tear-gassed.aspx|archive-url=https://archive.today/20130628050130/http://www.denbighshirefreepress.co.uk/news/123984/denbigh-man-tear-gassed.aspx|archive-date=28 June 2013|name-list-style=vanc|access-date=28 June 2013}}</ref> It is unclear how effective these remedies are. In particular, vinegar can burn the eyes and prolonged inhalation can irritate the airways.<ref name="TURI-vinegar">{{cite web|title=Vinegar EHS|url=http://www.turi.org/Our_Work/Green_Cleaning_Lab/Does_It_Clean/Do-it-Yourself_Recipes/Health_and_Safety/DIY_Health_and_Safety_Information/Vinegar-EHS|archive-url=https://archive.today/20130624234507/http://www.turi.org/Our_Work/Green_Cleaning_Lab/Does_It_Clean/Do-it-Yourself_Recipes/Health_and_Safety/DIY_Health_and_Safety_Information/Vinegar-EHS|archive-date=24 June 2013|access-date=22 June 2013|publisher=Toxics Use Reduction Institute, UMAss Lowell}}</ref>
Vegetable oil and vinegar have been reported as helping relieve burning caused by pepper spray.<ref name=Yeung /> Kräuter suggests the usage of baking soda or toothpaste, stating that they trap the particles emanating from the gas near the airways that are more feasible to inhale.<ref name="Tururu" /> A small trial of baby shampoo for washing out the eyes did not show any benefit.<ref name="Kim 2016" />
== See also == * Law of war * Baton (law enforcement) * Nerve gas * Rubber bullet
==References== '''Informational notes''' {{reflist|group=NB}}
'''Citations''' {{reflist}}
'''Further reading''' {{wiktionary}} {{commons category|Lachrymatory agents}} {{refbegin}} * {{cite book | last = Feigenbaum | first = Anna | name-list-style = vanc | year = 2016 | title = Tear Gas: From the Battlefields of WWI to the Streets of Today | location = New York and London | publisher = Verso | isbn = 978-1-784-78026-5 }} * Feigenbaum, Anna, "Tear Gas Design and Dissent" in Tom Bieling (Ed.) (2019): Design (&) Activism: Perspectives on Design as Activism and Activism as Design, Milano: Mimesis, pp. 97–104. {{ISBN|978-8869772412}} * {{cite journal | vauthors = Brône B, Peeters PJ, Marrannes R, Mercken M, Nuydens R, Meert T, Gijsen HJ | title = Tear gasses CN, CR, and CS are potent activators of the human TRPA1 receptor | journal = Toxicology and Applied Pharmacology | volume = 231 | issue = 2 | pages = 150–156 | date = September 2008 | pmid = 18501939 | doi = 10.1016/j.taap.2008.04.005 | bibcode = 2008ToxAP.231..150B }} {{refend}}
{{chemical warfare|state=collapsed}} {{Transient receptor potential channel modulators}} {{Authority control}}
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