What’s in the menu for your uprising: Scent-based weapons, Pepper gas, Tear gas – Çağrı Mert Bakırcı

Riot control methods: What’s in your riot’s menu? How to deal with them? – Çağrı Mert Bakırcı part 3.

The Turkish original of this article, “İsyan Kontrolünde Kullanılan Yöntemler ve Biyolojik Etkileri”, signed Çağrı Mert Bakırcı, was published on June 16th, 2013 in Evrim Ağacı.org. The content of the article is as follows: Introduction, The chemicals used in riot control and their biological effects, Pressurized water, Water cannon, Armed vehicles, Scent-based weapons, Pepper gas, Tear gas and its varieties, The expiration dates of gases and their effects, Why we feel that the effect of the gases change/increase, How to protect oneself, Batons, Conclusion.

We divided the article into parts and therefore restructured the sections for presentational purposes. The first part covered batons and pressurized water while the second covered water cannons and other armed vehicles. We will now discuss

  • scent-based weapons,

  • pepper gas, and

  • tear gas varieties.



Scent-based weapons

While they are used rather infrequently, scent-based weapons serve as an important example of non-lethal weapons. The malodorants, sprayed from water cannons, leave a terrible odor in the affected area and do not wash off easily. As a result the individuals feel like vomiting and cannot focus on the protest. Sometimes the toxicity of these chemicals can be so overly high that they can cause permanent damage.

As an example, Israel used them for crowd control in September 2008. (See photo below.)

Pepper Spray

According to the Wikipedia article on Pepper spray,

Pepper spray, also known as OC spray(from “OleoresinCapsicum“), OC gas, and capsicum spray, is a lachrymatory agent(a chemical compound that irritates the eyes to cause tears, pain, and temporary blindness) used in policing, riot control, crowd control, and personal self-defense, including defense against dogs and bears. Its inflammatory effects cause the eyes to close, taking away vision. This temporary blindness allows officers to more easily restrain subjects and permits persons using pepper spray for self-defense an opportunity to escape. Although considered a less-than-lethal agent, it has been deadly in rare cases, and concerns have been raised about a number of deaths where being pepper sprayed may have been a contributing factor.

The active ingredient in pepper spray is capsaicin, which is a chemical derived from the fruit of plants in the Capsicumgenus, including chilis.

This gas can be in different colors, depending on the amount of pepper and other additional chemicals constituting it. While the more common color is a grayish white, it can also be orange, brownish orange or yellowish orange. Sometimes colorants are added on purpose in order to block sight or paint the protesters.

Pepper gas is either sprayed from canisters or fired from a paintball gun. In the case of firing from a gun, its effect from short range is quite similar to actual guns. Hence, it is required that it is fired with an angle of 45 degrees to the ground. As the capsule is hot and fast, when fired from short distances, it causes burns, disruptions and serious brain/sight damages.

The above-mentioned Wikipedia article further states:

Pepper spray is an inflammatory agent. It causes immediate closing of the eyes, difficulty breathing, runny nose, and coughing. The duration of its effects depends on the strength of the spray but the average full effect lasts around thirty to forty-five minutes, with diminished effects lasting for hours.

The Journal of Investigative Ophthalmology and Visual Sciencepublished a study that concluded that single exposure of the eye to OC is harmless, but repeated exposure can result in long-lasting changes in cornealsensitivity. They found no lasting decrease in visual acuity.

The European Parliament Scientific and Technological Options Assessment (STOA) published in 1998 “An Appraisal of Technologies of Political Control” with extensive information on pepper spray and tear gas. They write:

The effects of pepper spray are far more severe, including temporary blindness which lasts from 15–30 minutes, a burning sensation of the skin which lasts from 45 to 60 minutes, upper body spasms which force a person to bend forward and uncontrollable coughing making it difficult to breathe or speak for between 3 to 15 minutes. …

… Direct close-range spray can cause more serious eye irritation by attacking the cornea with a concentrated stream of liquid (the so-called “hydraulic needle” effect). Some brands have addressed this problem by means of an elliptically cone-shaped spray pattern.

Capsaicinis not soluble in water, and even large volumes of water will not wash it off. In general, victims are encouraged to blink vigorously in order to encourage tears, which will help flush the irritant from the eyes.

A formal study of five often-recommended treatments for skin pain (Maalox, 2% lidocainegel, baby shampoo, milk, or water) concluded that:

“…there was no significant difference in pain relief provided by five different treatment regimens. Time after exposure appeared to be the best predictor for decrease in pain…”

Contact with liquid seems to have a relaxing effect, but there are no reports showing pain relief. In any case, the fluidity is considered to slightly reduce the pain caused by the pepper gas. Many ambulance services and emergency departments use baby shampoo to remove the spray. In general, the time for recovery can be reduced to 7-15 minutes with these extra treatments.



Tear Gas (Lachrymatory agent)

As the Wikipedia article on Tear Gas states, research shows that the use of tear gas has some serious risks:

As with all non-lethal, or less-than-lethal weapons, there is some risk of serious permanent injury or death when tear gas is used. This includes risks from being hit by tear gas cartridges, which include severe bruising, loss of eyes, skull fracture, and even death. While the medical consequences of the gases themselves are typically limited to minor skin inflammation, delayed complications are also possible: people with pre-existing respiratory conditions such as asthma, who are particularly at risk, may sometimes require hospitalization or even ventilation support. Skin exposure to CS may cause chemical burns or induce allergic contact dermatitis. 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.

There are several types of tear gas:

  • OC (Pepper spray) : See previous section.

  • CS gas (2-chlorobenzalmalononitrile): A capsule used in Istanbul during the uprising in 2013 can be seen below. While considered non-lethal, many studies have raised doubts to this classification by showing that it can cause pulmonary damage as well as damage to the heart and liver. Being exposed to CS gas indoors can significantly contribute to or even cause lethal effects. CS gas exposure is further correlated to miscarriages. As the Wikipedia article on CS gas states, according to studies, “CS contamination can be removed by washing with an alkaline solution of water and 5% sodium bisulfite.” The color of CS gas is typically light orange.


  • CR gas (dibenzoxazepine) : CR is a pale yellow solid with a pepper-like odor. As it is slightly soluble in water, its effects are not reduced when treated with water. It is usually fired in canisters that heat up, producing an aerosol cloud. According to the Wikipedia article on CR gas,

    Its effects are approximately 6 to 10 times more powerful than those of CS 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 suspected carcinogen. 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 by asphyxiation and pulmonary edema.

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

    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.

    The following video, “CR gas human test”, shows the effects of CR gas. CR gas is known to be commonly used in Ukraine, Israel and Egypt.

  • CN gas (Phenacyl chloride) :According to the Wikipedia article on CN gas, “Because of its significantly greater toxicity, it has largely been supplanted by CS gas. Even though CN is still supplied to paramilitaryand police forces in a small pressurized aerosol known as “Mace” or tear gas, its use is falling as pepper sprayboth works and disperses more quickly than CN.” A capsule can be seen below.



  • Nonivamide (pelargonic acid vanillylamide or PAVA) is a pepper gas derivative, more heat-stable than capsaicin. It is typically used as an active ingredient in pepper sprays.


  • BA (Bromoacetone): Bromoacetone is a colorless liquid used in World War I as a chemical weapon. It is highly toxic and is therefore not used in riot control.


  • Xylyl bromide (Methylbenzyl bromide or T-stoff): Also used as a chemical weapon in World War I but not in use for riot control, it is a colorless liquid with a pleasant aromatic smell.


  • syn-Propanethial-S-oxide: This is the chemical released from onions as they are sliced. In general, it is not used as a tear gas ingredient. Yet, we would like to keep it in our list as it has similar effects.


Ege M. Diren

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