|"Only dull people are brilliant at breakfast"
|"The liberal soul shall be made fat, and he that watereth, shall be watered also himself."
-- Proverbs 11:25
The reason pepper-spray ends up on the Scoville chart is that – you probably guessed this - it’s literally derived from pepper chemistry, the compounds that make habaneros so much more formidable than the comparatively wimpy bells. Those compounds are called capsaicins and – in fact – pepper spray is more formally called Oleoresin Capsicum or OC Spray.
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. The description hints maybe at that eye-stinging effect that the cook occasionally experiences when making something like a jalapeno-based salsa, a little burn, nothing too serious.
Until you look it up on the Scoville scale and remember, as toxicologists love to point out, that the dose makes the poison. That we’re not talking about cookery but a potent blast of chemistry. So that if OC spray is the U.S. police response of choice – and certainly, it’s been used with dismaying enthusiasm during the Occupy protests nationwide, as documented in this excellent Atlantic roundup - it may be time to demand a more serious look at the risks involved.
My own purpose here is to focus on the dangers of a high level of capsaicin exposure. 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.
Their paper focuses mostly, though, on the dangerous associated with pepper-based compounds. In 1997, for instance, researchers at the University of California-San Francisco discovered that the “hot” sensation of habaneros and their ilk was caused by capsaicin binding directly to proteins in the membranes of pain and heat sensing neurons. Capsaicins can activate these neurons at below body temperature, leading to a startling sensation of heat. Repeated exposure can wear the system down, depleting neurotransmitters, reducing the sensation of the pain. This knowledge has led to a number of medical treatments using capsaicins to manage pain.
Its very mechanism, though, should remind us to be wary. 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.
In general, these are short term effects. Pepper spray, for instance, induces a burning sensation in the eyes in part by damaging cells in the outer layer of the cornea. Usually, the body repairs this kind of injury fairly neatly. But with repeated exposures, studies find, there can be permanent damage to the cornea.
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.
And by genuine risk, I mean a known risk, a no-surprise any police department should know this risk, easy enough to find in the scientific literature.