Pepper spray (also known as OC spray (from "Oleoresin Capsicum"), OC gas, capsicum spray, or oleoresin capsicum) is a lachrymatory agent (a chemical compound that irritates the eyes to cause tears, pain, and even temporary blindness) that is used in riot control, crowd control, and personal self-defense, including defense against dogs and bears. It is a less lethal agent that can be deadly in rare cases. The American Civil Liberties Union documented fourteen fatalities from the use of pepper spray as of 1995. The active ingredient in pepper spray is capsaicin, which is a chemical derived from the fruit of plants in the Capsicum genus, including chiles. Long-term effects of pepper spray have not been effectively researched.
Extraction of oleoresin capsicum from peppers involves finely ground capsicum, then the capsaicin is extracted in an organic solvent such as ethanol. The solvent is then evaporated, and the remaining resin is the oleoresin capsicum. An additive such as propylene glycol is used to suspend the OC in water, and pressurized to make it aerosol in pepper spray. The high performance liquid chromatography (HPLC) method is used to measure the amount of capsaicin within pepper sprays. Scoville Heat Units (SHU) are used to measure the hotness of pepper spray.
A synthetic analogue of capsaicin, pelargonic acid vanillylamide (desmethyldihydrocapsaicin), is used in another version of pepper spray known as PAVA spray which is used in England. Another synthetic counterpart of pepper spray, pelargonic acid morpholide, was developed and is widely used in Russia. Its effectiveness compared to natural pepper spray is unclear and it has caused some injuries.
Pepper spray typically comes in canisters, which are often small enough to be carried or concealed in a pocket or purse. Pepper spray can also be bought concealed in items such as rings. There are also pepper spray projectiles available, which can be fired from a paintball gun. Having been used for years against demonstrators , it is increasingly being used by police in routine interventions.
