What is Tear Gas?

Author: ecobear | Date Posted: 17th July 2017 | Category: Consumer Education

Tear gas is a form of chemical weaponry designed as a non-lethal means of suppressing a threat. The technical names for tear gas are “lachrymator” or “lachrymator agent;” although Mace is the name for a specific brand of pepper spray, its proliferation among civilians has made it synonymous with any form of pepper spray in much the same way as the names Kleenex and Polaroid respectively refer to tissue paper and film.

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What Does Tear Gas Do to Your Body?
As the technical name for this non-lethal weapon is a lachrymator, tear gas is used to overstimulate the lacrimal nerve, inflicting pain and tear-inducing levels of irritation upon a person’s eyes, lungs and skin. Some varieties are potent enough to also cause bleeding and temporary moments of blindness and loss of motor functions.

How Does Tear Gas Affect Your Body?
What makes tear gas a weapon is it is designed to agitate the mucous membranes within the eyes, nose, mouth and even along the lungs. This results in fits of crying, sneezing and coughing, optical pain, impaired breathing and temporary loss of vision. The CS variety can take effect anytime between 1 minute to one-third of a minute after exposure and its effects will linger within half an hour of leaving the gassed area. The effects of pepper spray, also known as OC gas, include impaired mobility and take effect nearly as soon as a person is exposed. It should be noted that while some individuals are more or less resistant to the effects of any variety of tear gas, no one has shown immunity to the substance. Lastly, there are at least five known instances of fatal exposure from the increasingly outdated form of tear gas known as “CN;” death from CN exposure has manifested as either asphyxiation or injuries within the person’s lungs.

What are the Ingredients in Tear Gas?
The “payload” of a CS canister consists of the following:

  1. Charcoal. This is simply wood that has been almost completely carbonized. Pulling the pin on a CS grenade activates a fuse that causes the charcoal to smolder, leading to ignition with the potassium nitrate component.
  2. Potassium nitrate (KNO3). This is also known as saltpeter and serves as an oxidizer, generating large amounts of fire-fueling oxygen when burnt. While modern potassium nitrate is harvested from chemical ammonia, it was originally derived from the organic byproducts of bats and livestock.
  3. Silicon (Si). This reacts to the high temperatures (2,500° F) generated by igniting potassium nitrate and charcoal and transmutes into glass droplets that will spray onto other components to spread the heat.
  4. Sucrose (C12H22O11). This substance serves as additional fuel for the internal blaze. As a form of sugar, specifically one derived from plants, it melts at a mere 370° F and converts the lachrymator agent from a solid into a gas, rather than incinerate it into nothingness.
  5. Potassium chlorate (KClO3). This substance is an oxidizer much like potassium nitrate, but also breaks down into smoke-generating potassium chloride after it is introduced to high temperatures.
  6. Magnesium carbonate (MgCO3). Because Potassium chlorate is a basic substance that reacts explosively with acids, magnesium carbonate is used to keep the canister’s pH balance in check. Magnesium carbonate can be found in a variety of substances, including the chalk used on pool cues and as a component in fire extinguishers. When the canister’s contents become ignited, magnesium carbonate also produces carbon dioxide; expanding the potential dispersal area for the tear gas.
  7. 2-chlorobenzalmalononitrile (C10H5ClN2). Also known as “o-chlorobenzylidene malononitrile,” is the actual lachrymator agent of CS tear gas. Only 4 mg/m3 is necessary to disperse a crowd; 25 g/m3 is sufficient to be lethal.
  8. Nitrocellulose (C6H9(NO2)O5)n). While some versions of this compound, such as C6H8(NO2)2O5)n and C6H7(NO2)3O5)n are explosives or suitable as a lacquer for a fine musical instrument, CS uses a low-nitrogen version of this compound. The nitrocellulose applied toward CS gas functions as a binding agent that keeps all of the canister’s chemicals properly mixed.

Another form of tear gas, known as “CN gas,” “phenacyl chloride” (C8H7ClO) or informally as “Mace;” was once the go-to substance for non-lethal approaches. However, the development of CS gas from the 1950s onward and improvements to pepper sprays have left this substance by the wayside, especially because of its increased toxicity when compared to CS. While police and military forces use CS gas, some paramilitary organizations may rely upon CN gas as a substitute for CS or superior non-lethal ordinance.

The common pepper spray, formally known as “OC gas” due to its active ingredient oleoresin capsicum, derives its offensive capabilities from the waxy resin byproduct which results from extracting capsaicin from red peppers or other capsaicin-rich substances. Capsaicin is the organic compound in peppers and other spicy foods that gives them their signature “heat.” The OC is kept in an emulsifier and then pressured so that it can be sprayed into the face of an aggressor.

  1. C17H27NO3, more commonly known as “nonivamide” or “pelargonic acid vanillylamide” (PAVA), is a synthesized version of oleoresin capsicum that is used in some varieties of pepper spray.
  2. syn-Propanethial S-oxide (C3H6OS) is the chemical compound of onions that is released when they are sliced into. While it is insufficient as a non-lethal weapon, syn-Propanethial S-oxide is technically a form of tear gas.


How Does Tear Gas Work?
Lachrymator agents are specialized to focus on the enzymes within the body that contain sulfur in place of oxygen, especially throughout the trigeminal nerve. The trigeminal nerve is the largest of the head’s nerves and influences the ability to feel one’s face and governs the motion control of blinking and chewing; this is why tear gas affects the eyes, lungs, mouth and nose of anyone exposed. While the effects of most varieties of tear gas go away in well under an hour, pepper spray is a notable exception to the issue of durability; because pepper spray settles into the body’s nerve endings, the burning sensation can last several hours after it has been washed away from one’s face.

How Do You Remove/Cleanup Tear Gas Residue?
While humans can remove most tear gas residue by washing their skin, the removal of tear gas from objects or a room is not something that an untrained civilian should ever attempt. The very nature of the substance means that it can temporarily disable anyone who wanders into an area that has been gassed, potentially leading to declining property values and being classified as “uninhabitable” if left uncleaned.


The Removal Process for CS Gas is as Follows:

  1. Wear an OSHA-approved protected suit, complete with a respirator.
  2. Deactivate the HVAC system.
  3. Chill all effected rooms as much as possible, while being mindful to avoid dipping into freezing temperatures that could affect the water running through pipes. Because CS reacts to heat, the cold helps keep the residue from reactivating.
  4. Inspect the area and take photographs.
  5. Assess the presence or absence of bodily fluids that would be considered a biohazard. If blood or similar biohazards are present, their removals takes priority over the CS gas.
  6. Assess the amount of tear gas residue in the area. This includes checking what, if any, dyes were added to the gas and examining areas of drywall where one or more canisters may have broken through, exposing the studs of interior walls.
  7. Establish a base of operations. Normally, this will be a garage or some other adjacent room that is free of CS residue. The base will also serve as a place to store and clean non-porous furniture and items until such time as it is safe to restore them to the affected area.
  8. Because the particulates released by tear gas are “heavy,” they settle along the ground. It is with this behavior in mind that the removal process begins on the highest affected floor or room. This room, and the hallways/routes leading to it, should be sealed off with plastic. In cases where a large room needs treatment, the area can be tackled in quadrants or halves; ideally, technicians should divide the area no larger than 15 square feet at a time. Lastly, only use one exit at a time in order to stop workers from passing through cleaned rooms.
  9. Cover any and all air vents as a safeguard against re-contaminating a room with residue. Additionally, the presence of an air conditioner carries the potential for exposing basements and other areas to tear gas; make sure to check every room that an AC unit connects to and clean it accordingly.
  10. Remove and dispatch all porous substances, include carpets, pads, cloth, drapes, electronics, et cetera-anything that can store residue should be expunged. Most porous substances cannot be completely purged of residue and should be trashed.
  11. Relocate anything non-porous to the base of operations.
  12. In cases where drywall was punctured by one or more canisters, remove and trash both layers of the drywall and the insulation.
  13. Apply a HEPA vacuum to every affected surface in order to clean away as much residue as you can.
  14. Spray a specialized cleaning solvent, usually containing a small portion of soda or alkaline substances, to deactivate the residue and keep it from getting into the air.
  15. Wipe every surface free of residue, even the porous ones like walls and any exposed studs.
  16. Repeat this process several times until no trace of residue remains.
  17. In instances where wooden wall studs have been exposed to tear gas, apply a wood sealant to them. This prevents a stud from re-circulating gas via the residue that settled on it.
  18. Once a room has been sufficiently cleaned, it should be sealed off with a new layer of plastic and every sheet covering a point of entrance should be marked with an “X.” This way explains to others that they should stay out of the room until such time as the rest of the structure has been cleaned.
  19. Once the entire facility has been purged of residue, every worker should pass through the treated areas in order to reach a group consensus. It is only once no one has experienced any negative reactions from passing through the pertinent areas that the site is considered cleaned and any HVAC systems can be reactivated.


When Do Police Use Tear Gas?
Police forces are allowed to use tear gas in order to “smoke out” aggressors hiding inside of a building, to clear a room of hostiles during a breach or when they must otherwise suppress a large number of people. Much like the use of a taser, only officers who have gone through training with tear gas, including being exposed to the substance, are legally allowed to use tear gas. Additionally, police will not use a single canister when tear gas is called for-sometimes they will unload 100 or more. In the past, situations like an outdoor prison riot might be solved with the CBU-19; mounted to a helicopter, the CBU-19 cluster bomb was more than capable of deploying large quantities of tear gas from heights sufficient to cover a large crowd (no more than 600 feet above ground level).

The primary benefit of non-lethal ordinance like tear gas, beanbag rounds and rubber bullets is that they minimize casualties in the pursuit of maintaining law and order. When police use tear gas to break up a riot, the officers equipped with grenades or grenade launchers are positioned at least one layer of men behind the front line. Despite its effectiveness, tear gas is usually a last resort when it comes to quelling a riot. While some might believe that animal units would be more susceptible to tear gas, the furry coats and comparatively simpler physiology of most domesticated animals means that police dogs and horses can do their duty without having a severe reaction to CS gas or its residue.

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