Tear Gas Information

CN Tear Gas:

CN has been used in personal defense products since the 1920's. Among the first such products were tear gas pens and pistols that used a ballistic device, generally a blank pistol cartridge, to propel solid CN particles at an attacker. Not surprisingly, numerous mechanical and chemical injuries to the eye resulted from the use of these products.

Unfortunately, reports on the toxic ocular effects of CN from this type of exposure were usually confounded by traumatic injuries from the blast effect of the delivery device, and this makes it difficult to determine with certainty the exact extent of ocular damage resulting from CN exposure. In addition, the blast effect can drive CN into the deeper layers of the cornea or even into the globe. Such injuries would not be expected with exposures produced by personal defense sprays.

CN was marketed as a personal defense spray in 1965 by General Ordinance and Equipment Company under the brand name Mace. This product gained wide-spread popularity in the 1960's, and the term Mace is still incorrectly used as a generic term for all aerosol defense sprays.

A possible problem associated with the use of CN for personal defense is that it has been reported to have limited effectiveness against some individuals, notably those under the influence of alcohol or drugs, or those with certain mental disturbances. Additionally, it can take several seconds for CN to achieve its full effect, and the person using the spray would be vulnerable to attack during this time.

Exposure to CN at concentrations that might be produced by a defense spray usually results in extreme irritation of the eyes, burning pain, conjunctival hyperemia, lacrimation, and possibly blepharospasm. Concentrations of CN above those usually provided by defense sprays can cause more severe ocular complications including sloughing of the conjunctiva, corneal edema, and keratitis with subsequent risk of scarring. CN has also been reported to be capable of causing neuroparalytic keratopathy.

High concentrations of CN can also cause significant non-ocular effects including respiratory tract irritation, a burning sensation and erythema of exposed skin, irritation and burning of the oral and nasal mucosa, nasal congestion, and cough. Some individuals can experience nausea, vomiting, and headache following CN exposure, and primary contact dermatitis, allergic dermatitis and blepharitis have also been reported.

Selection from: "Pacific University College of Optometry"

CS Tear Gas:

In the 1950s, the Chemical Defense Experimental Establishment (Porton, England), developed CS. O-Chlorobenzylidenemalononitrile is a white crystalline substance that is usually mixed with a pyrotechnic compound in a grenade or canister for use. It's useful form is intended to be a smoke or fog of suspended particles. Effectiveness in crowd control derives from its properties as an extremely severe skin and mucous membrane irritant and lacrimator, even at minute doses. Instantaneous conjunctivitis with concomitant blepharospasm, burning and pain are characteristic. These symptoms are exacerbated in hot or humid weather.

Since its introduction, CS has virtually replaced CN as the riot control agent of choice in England and the United States. During the Vietnam War, the United States developed an array of delivery vehicles for CS, including small pocket grenades, the "Mighty Mite" (a continuous spray device used in caves and tunnel systems) and 58-kg cluster bombs dropped from helicopters and planes.

Toxicology of CS:

Military studies among volunteers have noted that, in most cases, removal from exposure to CS results in fairly rapid recovery with cessation of all symptoms within minutes. Proponents of the use of CS believe that, when used properly, high or prolonged exposure to the substance would be precluded by an individual's natural aversion to remaining in an area where the substance is present (United Kingdom patent specification 967 66; 1960). Its popularity among military and police authorities stems partly from comparisons with the other tear gas agents, which suggests that CS is a more potent lacrimator and seems to cause less long-term injury, particularly with respect to the eye.

Selection from: "Physicians for Human Rights"