Editing Chlorine (section)

==== World War I ====
{{Main|Chemical weapons in World War I}}

Chlorine gas, also known as bertholite, was first [[chemical warfare|used as a weapon]] in [[World War I]] by Germany on April 22, 1915, in the [[Second Battle of Ypres]].<ref>"Battle of Ypres" ''The Canadian Encyclopedia''</ref><ref name="CEN2015">{{cite journal | first = Sarah | last = Everts | url = http://chemicalweapons.cenmag.org/when-chemicals-became-weapons-of-war/ | title = When Chemicals Became Weapons of War | journal = Chemical & Engineering News | volume = 93 | issue = 8 | date = February 23, 2015 | url-status = live | archive-url = https://web.archive.org/web/20160330203223/http://chemicalweapons.cenmag.org/when-chemicals-became-weapons-of-war/ | archive-date = March 30, 2016 }}</ref> As described by the soldiers, it had the distinctive smell of a mixture of pepper and pineapple.<ref>{{Cite web |last=Patton |first=James |title=Gas in The Great War |url=https://www.kumc.edu/school-of-medicine/academics/departments/history-and-philosophy-of-medicine/archives/wwi/essays/medicine/gas-in-the-great-war.html |url-status=live |archive-url=https://web.archive.org/web/20240615142532/https://www.kumc.edu/school-of-medicine/academics/departments/history-and-philosophy-of-medicine/archives/wwi/essays/medicine/gas-in-the-great-war.html |archive-date=15 June 2024 |access-date=2024-06-21 |website=KU Medical Center |language=en-us}}</ref> It also tasted metallic and stung the back of the throat and chest. Chlorine reacts with water in the [[Mucous membrane|mucosa]] of the lungs to form [[hydrochloric acid]], destructive to living tissue and potentially lethal. Human respiratory systems can be protected from chlorine gas by [[gas mask]]s with [[activated charcoal]] or other filters, which makes chlorine gas much less lethal than other chemical weapons. It was pioneered by a German scientist later to be a Nobel laureate, [[Fritz Haber]] of the [[Kaiser Wilhelm Institute for Chemistry|Kaiser Wilhelm Institute]] in Berlin, in collaboration with the German chemical conglomerate [[IG Farben]], which developed methods for discharging chlorine gas against an [[trench|entrenched]] enemy.<ref>{{Cite book| url=https://books.google.com/books?id=G9FljcEASycC&pg=PA226| page=226| title=Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production| isbn=978-0-262-69313-4| author1=Smil, Vaclav| year=2000| publisher=MIT Press| url-status=live| archive-url=https://web.archive.org/web/20151231220856/https://books.google.com/books?id=G9FljcEASycC&pg=PA226| archive-date=2015-12-31}}</ref> After its first use, both sides in the conflict used chlorine as a chemical weapon, but it was soon replaced by the more deadly [[phosgene]] and [[mustard gas]].<ref name="First World War">{{cite web|url=http://www.firstworldwar.com/weaponry/gas.htm|title=Weapons of War: Poison Gas|publisher=First World War.com|access-date=2007-08-12|url-status=live|archive-url=https://web.archive.org/web/20070821004525/http://www.firstworldwar.com/weaponry/gas.htm|archive-date=2007-08-21}}</ref>