You might carry around your trusty bear spray on backcountry trips, but have you ever wondered what makes it so effective? If you haven’t, you’ve probably never been downwind of a blast.
“The spray cloud causes an involuntary closing of the eyes and irritation of the respiratory system, causing choking, coughing and constriction of the airways,” says George Hyde of Counter Assault, the first bear spray to be approved by the Environmental Protection Agency. It’s a nonlethal yet debilitating response. Sneezing, bronchoconstriction, apnea, laryngeal paralysis and temporary blindness join the litany of unpleasant effects.
According to Pride Johnson, President and chemist at Counter Assault, the root cause is inflammation. “The active ingredient in bear spray gets into the mucus membranes and makes the tissue swell,” he says. Dilation of the capillaries causes instant inflammation of the respiratory system. “Pepper sprays have an immediate reaction, whereas tear gases can take five to eight seconds to start working,” he adds.
Originally developed in the 1960s as a defense against aggressive domestic dogs, the active ingredient in bear spray is capsaicin, a natural chemical isolated from the seed capsules in certain red peppers. One ounce of purified capsaicin diluted in 750 gallons of water can make your tongue burn.
The capsaicin compound found in bear spray is mixed with oil to form Oleoresin Capsicum (OC). Bear spray manufacturers combine OC with a liquid so it comes out of the can in a foglike spray and add a propellant—only one to two percent of the contents of a can are pure capsaicin.
While people use a variety of deterrents for protection, including firearms, signal flares and an assortment of noisemakers, red pepper sprays remain the most effective, according to Stephen Herrero, professor at University of Alberta and author of Bear Attacks: Their Causes and Avoidance. An incident analysis by Herrero and his colleagues found that pepper spray stopped charging black and brown bears in 94 percent of cases.
This article originally appeared in Canoeroots & Family Camping, Early Summer 2013. Download our free iPad/iPhone/iPod Touch App or Android App or read it here.
