To sum up: the burning from so-called “pepper spray” is ten times more intense than that of the hottest peppers in existence, it can cause permanent respiratory, nerve, and eye damage, and in the mid-1990s was linked by the Justice Department to 70 deaths. Via Scientific American:
Aa American pharmacist named Wilbur Scoville developed a scale to measure the intensity of a pepper’s burn. The scale puts sweet bell peppers at the zero mark and the blistering habanero at up to 350,000 Scoville Units. Commercial grade pepper spray leaves even the most painful of natural peppers (the Himalayan ghost pepper) far behind. It’s listed at between 2 million and 5.3 million Scoville units. The lower number refers to the kind of pepper spray that you and I might be able to purchase for self-protective uses. And the higher number? It’s the kind of spray that police use, the super-high dose given in the orange-colored spray used at UC-Davis.
But we’ve taken to calling it pepper spray, I think, because that makes it sound so much more benign than it really is, like something just a grade or so above what we might mix up in a home kitchen.
But as pointed out in the 2004 paper, Health Hazards of Pepper Spray, written by health researchers at the University of North Carolina and Duke University, the sprays contain other risky materials:
Depending on brand, an OC spray may contain water, alcohols, or organic solvents as liquid carriers; and nitrogen, carbon dioxide, or halogenated hydrocarbons (such as Freon, tetrachloroethylene, and methylene chloride) as propellants to discharge the canister contents.(3) Inhalation of high doses of some of these chemicals can produce adverse cardiac, respiratory, and neurologic effects, including arrhythmias and sudden death.
As the North Carolina researchers point out, any compound that can influence nerve function is, by definition, risky. Research tells us that pepper spray acts as a potent inflammatory agent. It amplifies allergic sensitivities, it irritates and damages eyes, membranes, bronchial airways, the stomach lining – basically what it touches. It works by causing pain – and, as we know, pain is the body warning us of an injury.
The more worrisome effects have to do with inhalation – and by some reports, California university police officers deliberately put OC spray down protestors throats. Capsaicins inflame the airways, causing swelling and restriction. And this means that pepper sprays pose a genuine risk to people with asthma and other respiratory conditions.
Pepper spray use has been suspected of contributing to a number of deaths that occurred in police custody. In mid-1990s, the U.S. Department of Justice cited nearly 70 fatalities linked to pepper-spray use, following on a 1995 report compiled by the American Civil Liberties Union of California.