Chemical Mace is a tear gas in the form of an aerosol spray

Aerosol spray

Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles. This is used with a can or bottle that contains a liquid under pressure. When the container's valve is opened, the liquid is forced out of a small hole and emerges as an aerosol or mist...

 which propels a lachrymatory agent

Lachrymatory agent

Tear gas, formally known as a lachrymatory agent or lachrymator , is a non-lethal chemical weapon that stimulates the corneal nerves in the eyes to cause tears, pain, and even blindness...

 mixed with a volatile solvent. It is sometimes used as a self-defense

Self-defense

Self-defense, self-defence or private defense is a countermeasure that involves defending oneself, one's property or the well-being of another from physical harm. The use of the right of self-defense as a legal justification for the use of force in times of danger is available in many...

 device. This form of Mace is legal in very few countries, thus its use is becoming uncommon.

The original formulation consisted of 1% CN gas

CN gas

Phenacyl chloride is a substituted acetophenone. It is a useful building block in organic chemistry. Apart from that, it has been historically used as a riot control agent, where it is designated CN.-Preparation:...

 in a solvent of 2-butanol

2-Butanol

2-Butanol, or sec-butanol, is an organic compound with formula CH3CHCH2CH3. This secondary alcohol is a flammable, colorless liquid that is soluble in 12 parts water and completely miscible with polar organic solvents such as ethers and other alcohols. It is produced on a large scale, primarily as...

, propylene glycol

Propylene glycol

Propylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...

, cyclohexene

Cyclohexene

Cyclohexene is a hydrocarbon with the formula C6H10. This cycloalkene is a colorless liquid with a sharp smell. It is an intermediate in various industrial processes...

, and dipropylene glycol methyl ether

Propylene glycol

Propylene glycol, also called 1,2-propanediol or propane-1,2-diol, is an organic compound with formula C3H8O2 or HO-CH2-CHOH-CH3...

. Some formulations now also include oleoresin capsicum

Capsaicin

Capsaicin 2CHCH=CH4CONHCH2C6H3-4--3- ) is the active component of chili peppers, which are plants belonging to the genus Capsicum. It is an irritant for mammals, including humans, and produces a sensation of burning in any tissue with which it comes into contact...

 (the active ingredient in pepper spray

Pepper spray

Pepper spray, also known as OC spray , OC gas, and capsicum spray, is a lachrymatory agent that is used in riot control, crowd control and personal self-defense, including defense against dogs and bears...

).

Chemical Mace was originally invented in 1965 by Allan Lee Litman, founder and co-owner of Pittsburgh-based General Ordnance Equipment Corporation (GOEC), after his wife, Doris, was threatened on the street.