So... pepper spray... been running around trying to find solid info on it, which is proving very difficult.
What I have discovered is that there is a very wide variety of pepper sprays out there of varying intensity. The stuff police use tends to be around the 5 mil scoville range, while consumer defense varieties tend to be around 2 mil scovilles. Oleoresin Capiscum is only a minor component (from 10-15% it looks like), with the rest being composed of other stuff that enhances the effects (I've seen claims that the active ingredients in mace and tear gas are often mixed in and alcohol is commonly cited also) or controls the delivery of the spray (propellants/aerosols of questionable toxicity and water or oil based solutions, which is significant because the oil-based ones are incredibly difficult to flush off the skin). I've even seen claims that it's as bad or worse than the pepper sprays sold commercially as bear repellent, which at least
one vendor for Police Magnum OC Spray boasts openly on their website.
The claims about immediate health effects and dangers seem to be pretty consistent (well outlined
here and
here). The vast majority of the time, there are no long-term health effects or deaths... but they do happen and the experience is still torturously painful, so it's something that should be used very responsibly.
In summary:
It causes temporary blindness (lasting up to ~30 minutes), and usually (almost definitely for people who have never been sprayed before) causes the eyes to swell shut. Repeated exposures can cause permanent eye damage. Police have been caught in the past knowingly causing this kind of damage to prisoners, while using the stuff as a torture device. The most chilling case I've seen is from 1999 when police dipped q-tips into pepper spray solution and repeatedly touched it directly to the eyes of anti-logging protesters, which prompted the ACLU to file a suit to try and make the stuff illegal.
It causes immediate swelling of mucous membranes, and will cause skin to blister and rash after prolonged exposure with burns that I've seen reports of lasting over a week. Think about that when you see people sprayed and then dragged off in cuffs to sit for hours before processing and treatment. It also severely aggravates pre-existing forms of dermatitis, which raises alarms for me. Dermatitis has led directly to both of my MRSA infections, and I have a very hard time controlling it already.
The really dangerous part is when it gets directly into the nose, throat, or lungs. Besides the tissue damage, the inflammation causes difficulty breathing and swallowing. This has been linked to deaths by dozens of people with asthma or heart conditions at the hands of police. The literature surrounding this stuff even repeatedly warns that it's dangerous to inhale or swallow, but this is a warning that seems widely ignored.
And then there are allergies. I've seen very little description of what this entails, other than 'some people can have allergic reactions to components of the spray, and it's bad when that happens.'
It's also been accused in some medical literature of being carcinogenic, and is classified as a chemical weapon banned for use in war by the Geneva Convention.
For more in-depth information and contrast, I found both
academic and
government contracted research papers on the subject.
And finally, there has been shady business involved in the legality of the substance.
The head of the FBI's Less-Than-Lethal Weapons Program at the time of the 1991 study, Special Agent Thomas W. W. Ward, was fired by the FBI and was sentenced to two months in prison for receiving payments from a peppergas manufacturer while conducting and authoring the FBI study that eventually approved pepper spray for FBI use.[9][12][13] Prosecutors said that from December 1989 through 1990, Ward received about $5,000 a month for a total of $57,500, from Luckey Police Products, a Fort Lauderdale, Florida-based company that was a major producer and supplier of pepper spray. The payments were paid through a Florida company owned by Ward's wife.[14]
Edit:
A collection of pepper spray cop meme images. So many of these are totally ridiculous, though some of them are pretty good.