tear gas
Tear gas (also called lachrymatory agent or lachrymator) is a chemical weapon that causes extreme pain in the eyes, skin, nose, mouth and lungs. It can lead to vomiting, skin irritation, blindness and even death. Tear gas is usually contained in canisters fired from a riot gun but can also be deployed via hand-thrown grenade, spray or drone. Most forms of “tear gas” are not technically gases at all - they are airborne powders or liquids.
Tear gas particles connect to moisture - mucus, saliva, sweat, eyeballs etc. This causes uncontrollable crying, blurred vision or blindness, and irritation to the nose, mouth and lungs, leading in turn to more mucus and saliva production. Victims have described the feeling as “drowning in their own secretions” (1). The weapon is designed to disorient the victim and create fear, breaking up crowds.
As a chemical weapon, the use of tear gas is prohibited in warfare by the Geneva Protocol (2) and the Chemical Weapons Convention (3). However these treaties do not restrict police use of tear gas against civilians, and some countries such as the USA have repeatedly flouted the military ban.
Several chemicals may be referred to as “tear gas” including but not limited to:
CS gas (2-chlorobenzalmalononitrile) - this is by far the most commonly used.
CR gas (dibenzoxazepine) - also known as “firegas”. CR gas is rarely used because it is carcinogenic and more painful than CS gas.
Xylyl bromide (methylbenzyl bromide) - tear gas used in World War I.
Ethyl bromoacetate - tear gas used in World War I.
OC gas (oleoresin capsicum) - the chemical in “pepper spray” is sometimes deployed in canisters and may be referred to as “tear gas”.
CN gas (chloroacetophenone) - the original component of Mace brand spray. Most modern sprays colloquially referred to as “mace” actually contain oleoresin capsicum.
a brief history of tear gas use
French troops first used tear gas in August 1914 when they threw methylbenzyl bromide grenades, intending to drive German soldiers out from their trenches to be shot (4). Initially the chemicals used in World War I were potentially deadly but intended for use as a debilitating tear gas rather than to kill. These proved ineffective and were subsequently replaced by intentionally lethal gases such as chlorine and phosgene, and debilitating mustard gas. Following the war most nations involved signed the Geneva Protocol which banned the use of chemical weapons in war. The USA did not sign and in fact accelerated their development of chemical weapons.
From 1920 to 1929 white supremacist general Amos Fries was head of the US Chemical Warfare Service. Fries publicly campaigned for the police use of tear gas. One interviewer said of him:
“[Fries had] given much study to the question of the use of gas and smokes in dealing with mobs as well as with savages, and is firmly convinced that as soon as officers of the law and colonial administrators have familiarized themselves with gas as a means of maintaining order and power there will be such a diminution of violent social disorders and savage uprising as to amount to their disappearance”(5).
In 1927 tear gas canisters were designed with the explicit aim of being fired directly at unarmed civilians. The manufacturer B.C Goss said “These shells are intended to be used, namely, for firing directly in the faces of rioters or mobs, at short range by guards.” According to the Chemical Warfare Service “the charge must be received full in the face or on the body to be effective” and “will be effective against unarmed individuals, but will only stop a determined and armed individual when fired point blank”(6).
In 1928 CS gas was first synthesised by American scientists Ben Corson and Roger Stoughton. The name was derived from their initials (7). CS gas went on to become the most prevalent substance used by police.
Throughout the late 1920s and 1930s tear gas was exported overseas and sold to police departments across the US in anticipation of labour strikes (8). The British used tear gas extensively in their colonies, particularly Northern Ireland. In one incident the British authorised the use of CR gas on Northern Irish inmates at Long Kesh prison. It was allegedly deployed on 16 October 1974, leading to over 50 prisoners dying or developing cancer (9).
New methods for deploying tear gas are in development. Colombian and Israeli forces have used the VENOM Launcher with up to 30 tubes for firing tear gas (10). In 2022 the Indian Border Security Force developed a drone that drops tear gas grenades (11). The weapon was first used against protesting farmers in 2024 (12).
dangers of tear gas
The euphemistic name “tear gas” implies that it is a mild chemical irritant, like getting shampoo in your eye. In reality, tear gas can be deadly.
Tear gas is especially dangerous when fired into enclosed spaces, or when somebody is hit directly by a tear gas canister.
Tear gas is especially dangerous to asthmatics, children and the elderly.
Direct impact from a tear gas canister can break bones and cause brain trauma (13). In some cases this leads to limb amputation or death.
Tear gas can cause chemical burns to the skin which result in permanent scarring (14).
Despite authorities attempting to portray tear gas as a humane form of crowd-control technology, it has killed many people. Some recent examples include:
In 2012 in Bahrain an asthmatic man died after being repeatedly exposed to tear gas, and doctors reported an increase in miscarriages after tear gas exposure (15).
In August 2013 Egyptian police fired tear gas into a van crowded with prisoners, causing the suffocation of 37 people (16).
On February 8 2015 Egyptian police fired tear gas into crowds at a soccer stadium, causing mass panic. At least 25 people died from suffocation or trampling (17).
In October 2015 Israeli police killed Ramadan Mohammed Faisal Thawabta. The eight-month old Palestinian baby suffocated after being exposed to tear gas (18).
In May 2017 Israeli soldiers fired tear gas into the bedroom of another baby - Abdul Rahman Barghouti. He died two months later of asphyxiation after treatment failed (19).
In October 2022, Indonesian police fired tear gas into crowds at the Kanjuruhan stadium, causing panic and a crowd crush that killed 135 people (20).
countermeasures
Although tear gas is an effective and dangerous weapon in the hands of police, activists have developed methods to prevent inhalation and provide first aid. Access to tear gas and research into its effects is tightly controlled by police, the military and manufacturers, so methods to counter the gas have largely emerged through trial and error on the street rather than in laboratories. As such the methodology is continually being improved upon, and advice may change in the future.
preparation
Wear clothing that covers as much skin as possible. A bandana, scarf or balaclava should be used to cover your face, which is more effective if soaked in water.
Gas masks and respirators are more effective than cloth but are not widely available. Makeshift versions can be crafted with cloth or plastic bottles.
Wear swimming goggles to protect your eyes.
Avoid wearing contact lenses as the tear gas particles can lodge between the lens and your eye (21).
If tear gas lands near you:
If you don’t have a gas mask and goggles, you should hold your breath and immediately move away. Tear gas will concentrate near the ground so keep your head high.
Tear gas canisters can be thrown back at police, but they may be extremely hot. Gloves, slings, or other devices should be used to avoid burns.
Tear gas canisters contain a small fire which propel the substance outwards. Extinguishing the fire will neutralise the weapon. This can be done by:
Covering a canister with a traffic cone then pouring water through a hole in the top of the cone (22).
Alternatively you can drop the canister in water. This requires touching the canister which is dangerous without gloves.
Some activists have dispersed tear gas with leaf blowers (23) or have knocked canisters back with tennis rackets (24).
first aid
A person affected by tear gas should be moved into an area with fresh air. Contaminated clothing and contact lenses should be immediately removed.
Flush eyes with water but be careful not to just spread the substance around. Pour water over one eye at a time.
Activists have used various other solutions such as vinegar, lemon juice or petroleum jelly to treat tear gas injuries but these methods have not been scientifically proven (25).
In 2019 Hong Kong and Chilean protestors used a solution of 3 teaspoons baking soda to 1 cup of water sprayed on to faces to treat tear gas injuries (26).
If you have asthma or any other respiratory illness seek immediate professional medical attention.
aftermath
Have a cool shower. Warm water can open your pores causing more pain (27).
Wash contaminated clothes several times with cold water. Do not mix with other laundry.
references
(1) What to do if you’re exposed to tear gas | Popular Science (popsci.com)
(2) 1925 Geneva Protocol – UNODA
(4) Tear Gas: From the Battlefields of World War I to the Streets of Today (independentsciencenews.org)
(5) Knappen, T.M. 1921, ‘War Gases for Dispersing Mobs’, Gas Age-Record, vol. 48, no. 19, pp. 701–38.
(6) The Man Behind the Mask (jacobin.com)
(7) Cs | Article about Cs by The Free Dictionary
(8) 100 Years of Tear Gas - The Atlantic
(9) Secret gas was issued for IRA prison riots | Politics | The Guardian
(11) Tear Smoke Unit (tearsmoke.org)
(12) Haryana Police is first force to use drones for tear gas (thehindu.com)
(14) Worthington, E. & Nee, P.A. 1999, ‘CS exposure--clinical effects and management’, Journal of accident & emergency medicine, vol. 16, no. 3, pp. 168–70.
(16) Egypt police convicted over detainee tear-gas deaths - BBC News
(17) Soccer Stadium Stampede Kills at Least 25 in Egypt - The New York Times
(18) Israeli forces kill three Palestinians including a baby - Al Jazeera
(19) Palestinian baby dies from tear gas inhalation: PA | Conflict News | Al Jazeera
(20) Tear gas used by police causes panic and 135 deaths in Kanjuruhan Stadium (lethalindisguise.com)
(21) What to do if you’re exposed to tear gas (popsci.com)
(22) Watch how Hong Kong protesters extinguish tear gas (youtube.com)
(23) Portland protesters counter teargas with leaf blowers in standoff with federal troops (youtube.com)
(24) Watch: Protesters use tennis rackets to bat away tear gas (youtube.com)
(25) What to do if you’re exposed to tear gas (popsci.com)
(26) What to do if you’re exposed to tear gas (popsci.com)