What the evidence says about pepper spray safety

The casual and close-range use of pepper spray on nonviolent protesters: It's not just morally bankrupt, it's also not evidence based!

Judy Stone is a doctor, infectious disease specialist, and the author of a book on how to properly conduct clinical research. She's got a guest post on Scientific American blog network looking at the scientific research that's been done to document the effects and safety of pepper spray, and how to treat exposure to pepper spray.

Shorter version: The evidence basis behind the use of pepper spray, especially in the sort of contexts one is actually likely to encounter in the real world, is woefully limited. (It's a lot like tasers that way. In both cases, the research that does exist has mostly been done using physically fit, healthy, adult subjects who are not emotionally or physically distressed in any way at the moment they are hit. They're also being hit using manufacturer recommended dosages and distances of application. Real-world data suggests there's a MASSIVE difference between the effects of that sort of scenario and, say, a terrified teenager being shot in the face at point-blank range. Or an old woman who has been walking quickly, trying to get away from police. Just to throw some hypotheticals out there.) Meanwhile, the evidence that does exist strongly suggests that police forces are currently using pepper spray in ways that are inappropriate and unsafe. Evidence. Not opinion.

Also: Liquid antacids seem to be the best way to alleviate the effects of pepper spray. Perhaps it's time to stock up on Maalox.

There are reports of the efficacy of capsaicin in crowd control, but little regarding trials of exposures. Perhaps this is because pepper spray is regulated by the Environmental Protection Agency, as a pesticide and not by the FDA.

The concentration of capsaicin in bear spray is 1-2%; it is 10-30% in “personal defense sprays.”

While the police might feel reassured by the study, “The effect of oleoresin capsicum “pepper” spray inhalation on respiratory function,” I was not. This study met the “gold standard” of clinical trials, in that it was a “randomized, cross-over controlled trial to assess the effect of Oleoresin capsicum (OC) spray inhalation on respiratory function by itself and combined with restraint.” However, while the OC exposure showed no ill effect, only 34 volunteers were exposed to only 1 sec of Cap-Stun 5.5% OC spray by inhalation “from 5 ft away as they might in the field setting (as recommended by both manufacturer and local police policies).”

By contrast, an ACLU report, “Pepper Spray Update: More Fatalities, More Questions” found, in just two years, 26 deaths after OC spraying, noting that death was more likely if the victim was also restrained. This translated to 1 death per 600 times police used spray. (The cause of death was not firmly linked to the OC). According to the ACLU, “an internal memorandum produced by the largest supplier of pepper spray to the California police and civilian markets” concludes that there may be serious risks with more than a 1 sec spray. A subsequent Department of Justice study examined another 63 deaths after pepper spray during arrests; the spray was felt to be a “contributing factor” in several.

A review in 1996 by the Division of Epidemiology of the NC DHHS and OSHA concluded that exposure to OC spray during police training constituted an unacceptable health risk.

Remember kids: When you think "pepper-spraying cop" and "unacceptable health risk," you should also think, "Lt. John Pike."


  1. I’ve noticed BB beginning to frequently use the term “chemical weapons” regarding these sprays.  I think it’s a good frame to go with.

    As in “he used chemical weapons on his own people!”

    Though I also think of cheerleaders when I hear the word “baton.”  I guess we’re lucky the news doesn’t call them “tickle-sticks.”

      1. I’ve heard it’s delicious, kids are literally lining up for it.

        My brother in law, who is Malaysian, invited me to a barbecue run by his church. They had two woks running hot and the aerosol gave me coughing spasms. My bother in law inhaled the mix and said Ah! Pepper spray!.

    1. As in: he used “Chemical weapons” that are banned for use in war under the Geneva Convention, on his own people!

  2. Kids might also want to think “vicarious liability.”  Chancellor, can you say “non-delegable duty of care?”  I knew you could.

  3. The pepper spray used at the WTO protests could not be washed off with soap and water: it was designed to release more nasty if you tried. The best way to deal with that stuff that I found was to use a pat of butter to dissolve the residue, and then wipe all that off before using soap and water.

    I wonder if the same agent is being used now?

  4. While we are on this topic, is there a pepper-spray equivalent of “Excited Delirium”? A suitably sciencey sounding term for definitely-related-to-the-perp’s-preexisting-moral-terpitude-not-our-spraying-him-and-beating-him-until-he-stopped-moving mortality that can result?

  5. Sorry for going slightly off topic, but can someone please tell me what’s the reference for the pic used above? It looks like Leonardo de Caprio, but I’m just not getting the joke and it’s driving me nuts!

  6. Perhaps we need to refer to these weapons not as “non-lethal” nor as “less lethal” but as occasionally lethal or potentially lethal or “we really hope this time it won’t be lethal”

    1.  perhaps we just need to refer to these as weapons, since only one side has them I think it’s nitpicking to go beyond that.

    2. I got the feeling, looking at the video, that the cop who sprayed these kids like cockroaches would have loved to see them die.

  7. I wonder if a decent coat of vaseline would protect at least the skin against most of the chemicals in use at the moment?  And wouldn’t good old baking soda be a functional antacid?  A lot cheaper than Maalox anyway.  Could have some of those hand-pumped garden pressure sprayers with a baking soda slurry and just hose down the whole crowd right afterwards.  Of course I barely squeaked through high-school chemistry, so I could be way off base here – “is there a chemist in the house?”


      I used work in a crew that sprayed coal-tar emulsion on the interior of domestic water storage tanks.  Coal tar has some kind of oil in it that will burn your skin right off.  One day someone came up with the idea of smearing Vaseline all over our faces where they were exposed (it was not until many years later that air-supplied hoods were used).

      We all got burned worse than ever.  It was really really bad.

      The oil in the coal tar that causes the burns collects in the Vaseline. Vaseline may shed water (because water and oil don’t mix), but an oil will dissolve into the Vaseline (which is just highly refined petroleum–i.e., oil).

      I would be very surprised if oleoresin capsicum (which is obviously an oil) would not accumulate in Vaseline in the same way.

  8. An Egyptian friend told me that, on the tear-gas front, the cops have not been catching up. The February uprising caught them flat-footed, and most of their gas had gone stale, or had even expired. Since then, they’ve stocked up on newer, stronger stuff from the US and Israel.

    Somewhat effective countermeasures include masks with layers of activated charcoal and a 5% solution of baker’s yeast.

  9. Last time I heard here in Switzerland water cannons used by the police have tear gas mixed in for riot control. Ironically, Switzerland has signed a treaty against chemical weapons such that the same mix cannot be used against foreign invaders. Only against locals… (not sure how trustworthy this page is, which I found by googling for appropriate terms: http://www.ssi-media.com/pigbrother/Dokgas.htm)

  10. Lets also look a purity. The quality controls used to ensure product purity for a something that is intended to be sprayed into peoples eyes. Consider that eyes are in a loose socket attached via muscles to the skull and via a nerve directly to the brain.
    What level of control is used to ensure no toxic contaminants and no infectious organisms, in what is basically a medical application designed to torture the recipient and force submission via the extended application of extreme pain.
    What kind of society condones these kinds of weapons to be used upon their own population.
    What is the constitutional basis for their use, without the person being charged with a crime, without arrest and, without any form of due process.
    How in any way does using this product differ from say a public whipping, a punishment abolished decades ago by a less cowardly generation that forced it’s removal.
    Is it not the very definition of cruel and unusual punishment?

    1. Is it not the very definition of cruel and unusual punishment?

      Nope. That’s what the JUDICIAL BRANCH is not allowed to assign.

      This is the very definition of assault with intent to maim.

  11. Capsicum also has some tricky chemical interactions – ACE inhibitor (causes a dry cough, and possibly messes with high blood pressure medication), it’s an anticoagulant agent (so tricky if you’re on blood thinners – warfarin, voltarin – even aspirin and ibuprofen! – etc), makes cocaine more dangerous (higher risk of heart attack), messes with sedatives, messes with antidepressants.

    Antidepressants in particular – interaction can cause psychosis, hypertensive crisis, serotonin crisis – and that last one is veeery interesting, as symptoms include twitching, overresponsive reflexes, hypervigilance and agitation.

    So a good dose of capsicum on an individual on meds / coke is risky.  On an individual on antidepressants – seems it might make them react negatively to an arrest situation!  I wonder what response that would draw from an officer trained to subdue with pepper spray?  MORE!!  MORE!!  Armlock!!  Resisting arrest, damnit!  MORE!!

    “Why’s he holding his chest and twitching like that?”

    How many people did you say died after pepperspray administration?  27 … or 61 associated?

    Even the US Army didn’t like it much – from the Pepperspray entry at wikipedia:

    The US Army concluded in a 1993 Aberdeen Proving Ground study that pepper spray could cause “[m]utagenic effects, carcinogenic effects, sensitization, cardiovascular and pulmonary toxicity, neurotoxicity, as well as possible human fatalities. There is a risk in using this product on a large and varied population”.[

    Man, that’s some nasty shit!

  12. Out of curiosity, what are the legal charges used against civilians, if a civilian uses pepper spray against another civilian, or against a law enforcement personnel?

  13. I find it highly objectionable that police are all too willing to abuse so called non-lethal alternatives. The original idea behind their introduction was as an alternative to pulling a gun on someone. I think that whenever an officer uses whatever kind of force he should be required to submit an action report or whatever it is called, just as if he had discharged a firearm.

  14. Would I be right in assuming that a dose of Old Spicy would really ruin your contact lenses, too?  Gack under lenses is evil enough without having to remove them while pitching an agony fit in a dirty place.  Classy.

    Thing about all these “less-lethal” weapons is that, exactly as the pesky Left and civlib folks predicted, the people with them use them casually to enforce compliance.  Not to protect, to enforce compliance.   Now, I’m sure that cops are happy not to get in fracas, but it means the threshold of enforcement comes way, way down. 

    Using it as human bug spray is functionally equivalent to beating them so they’re easier to arrest, but without that pesky risk – making it more attractive to a certain mindset. 

    This whole thing needs some big class-action lawsuits.

  15. It might suprise people to know that while OC spray is dangerous and can cause health issues you are more likely to be injured if a cop just puts his hands on you than if OC is used. Yep nothing is safe or guarantied but used reposible OC is safer than westling with someone and not for the police but for the suspect. Now I don’t know if the protesters needed to be removed or not but 95% of the arguments used are ignorant or just plain faulse. This is an example.  Also some facts are wrong or misleading in the excerpted article. Civilian and Law Enforcement Pepper sprays range from 0.18% to 1.33% Major Capsaicinoids. Bear Sprays range from 1.0% to 2.0% Major Capsaicinoids. There are 5 Capsaicinoids or types of pepper used in OC spray. The amount of Oleoresin Capsicum, one of those 5 Capsaicinoids, does not indicate how strong the spray is. It’s a combination of total  Capsaicinoids  and the amount of Oleoresin Capsicum. Trust me though bear spray is much stronger. In the ACLU study none of the deaths were directly atributed to OC spray and all but 2 were drunk or on drugs. The other 2 were……well had mental issues. Really being drunk and being arrested looks more dangerous than OC and the same.

  16. Ticked off about the Police State’s thuggery for the 1%?
    Lets have some FUN on Black Friday.

    Go to your “local” Corporate Big Box. Fill your cart with the “hottest” consumerist items. Cover with other Corporate crap. Then- Abandon the cart in some inconspicuous place, like near the bathrooms or at the register saying you’ll be right back – forgot your wallet in the car.

    Rearrange the store, place condoms next to the baby clothing, hide electronics behind the laxatives.

    Then, later this weekend, shop locally from small businesses and craftspersons. Consider making (wow, actually making something) your gifts. Spend quality time with your family and friends rather than spending money you don’t have on trinkets no one needs made in a place whose human rights record everyone wishes they could forget.

  17. “…death was more likely if the victim was also restrained.” Say what? I can’t see any motive other than sadism to spray that stuff on someone who is already restrained.

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