The same compounds that give habaneros their bite is the same thing that sprays out of the cans used by police.
Pepper spray is derived from the same things you find in hot sauce but at much higher concentrations.
Although the use of pepper spray is widespread in the United States by law enforcement, U.S. troops fighting overseas are banned from using it in combat by international treaty.
Pepper spray, also known as oleoresin capsicum or OC, is made from the same naturally-occurring chemical that makes chili peppers hot, but at concentrations much higher. Its effects include temporary blindness, coughing and skin irritation.
To make the spray used by law enforcement officers and police to control crowds, manufacturers take a concentrated oil made from chili peppers and combine it with water, glycol (a chemical used in shaving creams and liquid soaps) and a propellent such as nitrogen, according to Bob Nance, vice president of operations at Security Equipment Corp. The company makes pepper spray and other irritants at its Fenton, Mo., headquarters under the Sabre brand name.
"We get it in a red, oily viscous syrup," Nance said. "It's the same thing you will find in hot sauce, but in higher concentrations."
Interest in pepper spray was piqued after a video of campus police spraying peaceful protesters at the University of California, Davis, made the rounds on the Internet this weekend. The university suspended its police chief and two officers. The video shows an officer spraying protesters in the face as they are sitting on the ground.
"It causes your eyes to shut and makes breathing difficult," Nance said. "It can cause coughing and choking, and a severe burning sensation on your face. But it's temporary, usually it lasts from 30 to 45 minutes."
Pepper spray comes in several strengths, ranging from 1 percent to 10 percent OC. That's equivalent to 2 million to 15 million Scoville Heat Units (SHU), which is a measure of the potency of the chili pepper extract.
The sprays also come in two forms -- as a fogger and as a stream.
Pepper spray has been used since the early 1970s, when it was developed for FBI agents and letter carriers facing mean dogs.
As for its hazardous effects, a 1999 study, "Health Hazards of Pepper Spray," by Dr. Gregory Smith of the University North Carolina, found that in the 1990s, 70 deaths of suspects in custody of police were associated with the use of pepper spray. The deaths were blamed on asphyxia or choking by the victims who had been hog-tied by police, who were intoxicated or under the influence of drugs or had pre-existing medical conditions and whose death could not be blamed on the spray itself.
A 2001 study by the National Institute of Justice and conducted by the researchers at the University of California, San Diego used pepper spray on 34 subjects.
The results showed that those in the sitting position did not face increased risk of respiratory compromise or choking, but it did cause increased blood pressure, according to the study. The study used healthy young subjects, who were not subject to numerous sprays.
Dr. Richard Clark, director of the Division of Toxicology at the University of California, San Diego Medical Center, says that most effects of pepper spray are short-lived, although they could have a stronger effect on people with asthma or other pre-existing respiratory conditions. He said pepper spray acts by stimulating pain centers. Clark said he was surprised by the use of the pepper spray that he saw in the video.
"They didn't appear to be threatening," Clark said of the protesters.
Although the use of pepper spray is widespread in the United States by law enforcement, U.S. troops fighting overseas are banned from using it in combat by international treaty. Vance said, however, that his firm does sell some to military police guarding prisoners.