What is tear gas?

What is tear gas? What are “lachrymatory agents”?

The term “tear gas” is applied to numerous substances, although the most common one currently in use internationally is what is called “CS gas.” CS is one of many so-called “nonlethal” chemical weapons referred to as “lachrymatory agents” (which comes from “lacrima,” the latin word for “tear.”) The category “lachrymatory agents” also includes chemicals commonly known as pepper spray (OC, PAVA) and mace (CN). Technically, tear gas and pepper spray are thought of as different substances. (For instance, most people probably think of tear gas as a gas and pepper spray as a liquid, however either chemical can come in various forms depending on how it is prepared.) However, they are both lachrymatory agents used by the state to stifle dissent and to terrorize prisoners, and they are often manufactured by the same companies (sometimes they are also combined in the same product.)

The term “tear gas” is a misnomer. For one thing, “tear gas” seems to imply something innocuous— you would think it’s just a chemical that makes you tear up. In fact, tear gas is a dangerous, potentially lethal chemical agent which is outlawed under the Chemical Weapons Convention for use during wartime. As the Omega Research Foundation argues: “Less-lethal weapons are presented as more acceptable alternatives to guns. But these weapons augment rather than replace the more lethal weapons. Euphemistic labels are used to create the impression that these weapons represent soft and gentle forms of control. CS is never referred to by the authorities as vomit gas, in spite of its capacity to cause violent retching.” NGO Physicians for Human Rights believes that “ ‘tear gas’ is a misnomer for a group of poisonous gases which, far from being innocuous, have serious acute and longer-term adverse effects on the health of significant numbers of those exposed.” We aim to change the conversation on tear gas by calling this so-called “nonlethal” weapon what it is: a chemical weapon. We view tear gas, pepper spray, and all “lachrymatory agents” and so-called “non-lethal weapons” as chemical weapons in the war on democracy.

It’s important to note that “tear gas” is not actually a gas. The active chemicals in all different kinds of tear gas and pepper spray are solid at room temperature, and need to be mixed with other chemicals in order to produce what is called an aerosol— solid particles finely dispersed in the air, similar to smoke or a cloud. They can also be dissolved in liquid solution, which is how pepper spray is commonly used. This is significant since the symptoms and treatment for tear gas and pepper spray exposure can vary depending on the kind of aerosolizing agents or solvents used. For example, when silica gel is added to CS to form CS1 or CS2, the result is a stronger tear gas which is more water resistant. Methylene chloride— a known carcinogen— was used as a solvent in the tear gas and pepper spray against WTO protesters in Seattle in 1999. This is believed to have caused many health problems for protesters who were exposed.

Different Kinds of Tear Gas:

CS, CS1, CS2 - most common form of teargas

2-Chlorobenzalmalononitrile (also called o-chlorobenzylidene malononitrile) (chemical formula: C10H5ClN2), commonly known as CS.

CS is by far the most common form of teargas used. CS can be combined with silica aerogel to form CS1 and CS2, “which increases the fluidity and water resistance” as well as the intensity of the symptoms. CS was first developed in 1928 by US scientists Ben Corson and Roger Stoughton, and it is named after their last initials.

CN - commonly referred to as “mace”, also called “tear gas”

Chloracetophenone (also called Phenacyl chloride or 2-chloro-1-phenylethanone) (chemical formula: C8H7ClO), more commonly known as “mace.”

CN is far more toxic and intense than CS, and is known to be able to cause permanent eye damage. Although CN is more commonly known as "mace," it is also referred to as "tear gas."

CR- also called “teargas”

Dibenz (b, f)-1, 4-oxazepine, or Dibenzoxazepine.

CR is far more intense and toxic than CS. For this reason, CR has largely, although not entirely, been replaced by CS.

OC and PAVA- "pepper spray."

8-Methyl-N-vanillyl-trans-6-nonenamide (OC, chemical formula C18H27NO3) and N-[(4-hydroxy-3-methoxyphenyl)methyl]nonanamide (pelargonic acid vanillylamide, PAVA, chemical formula C17H27NO3), more commonly known as “pepper spray.”

OC is actually derived from chili peppers, whereas PAVA is a similar chemical which is made synthetically.