TIME / Thomas K. Fowler / AP

Video footage of police using pepper spray on peacefully protesting students at the University of California, Davis, on Nov. 18 has sparked national outrage. But the use of such brutal force against passive protesters isn't as uncommon as you'd think.

Pepper spray and other severe tactics have recently been used with disturbing frequency by police against Occupy protesters — young or old or pregnant — around the nation (see this Atlantic roundup). But the agent's misuse goes back much further: in the mid-1990s, the U.S. Department of Justice cited nearly 70 fatalities linked to pepper-spray use, according to an excellent post on the dangers of pepper spray by science writer Deborah Blum on Speakeasy Science.

Blum notes that in a 1995 report [PDF], the American Civil Liberties Union of California cited 26 deaths between 1993 and 1995 possibly linked to pepper-spray use by police (that's 1 death for every 600 uses); most deaths involved people who had underlying health problems like asthma. And in 1999, following an incident in which California police officers dipped cotton swabs into pepper spray and then forced them into the eyes of anti-logging protesters, the ACLU asked an appeals court to declare the use of pepper spray to be dangerous and cruel.

How painful is getting pepper-sprayed? For starters, as Blum points out, police-grade pepper spray gets 5,300,000 Scoville heat units on the Scoville scale of pepper hotness. Compare that to 350,000 Scoville units for the habanero. (Pepper spray — or OC spray, as it's also known — contains the same compound that makes peppers hot, capsaicin, in a super-concentrated extract called oleoresin capsicum.)

In most cases, pepper spray is non-lethal, but it is known to cause irreparable harm or, as we've noted, death. According to a 2004 paper by researchers at the University of North Carolina School of Public Health and Duke University Medical Center, high-dose exposure to OC spray can produce "adverse cardiac, respiratory, and neurological effects, including arrhythmias and sudden death"; acute exposure also causes "nausea, fear and disorientation." Wrote the researchers:

Respiratory responses to OC spray include burning of the throat, wheezing, dry cough, shortness of breath, gagging, gasping, inability to breathe or speak (due to laryngospasm or laryngeal paralysis), and, rarely, cyanosis, apnea, and respiratory arrest. Nasal application of capsaicin causes sneezing, irritation, and reflex mucus secretion. Its inhalation can cause acute hypertension (similar to ammonia inhalation), which in turn can cause headache and increase the risk of stroke or heart attack.

Getting pepper-sprayed is worse than getting maced [PDF] — mace causes burning but no respiratory effects. Pepper spray can fell even people with a high tolerance for pain because it restricts the airway and leaves you gasping for breath. Even when pepper spray isn't inhaled, its effects on the skin and eyes can require hospital attention, causing intense burning pain, swelling, inflammation and redness.

Classified as a riot-control agent and banned for use in war by Article I.5 of the Chemical Weapons Convention, pepper spray is meant to be used against violent attackers who are resisting arrest and threatening physical harm to others. That doesn't apply to the passive protesters at U.C. Davis.

"Pepper spray should only be used when there's a clear threat to officers or severe-enough resistance — essentially, when the only alternative is more extreme force," John MacDonald, professor of criminology at the University of Pennsylvania, told our colleague Nick Carbone over at NewsFeed. "But if the only threat is time, then the best weapon to exercise is patience."

Following the misuse of pepper spray at U.C. Davis, one of the university's faculty members, Nathan Brown, an assistant professor of English, called for the resignation of the school's chancellor, Linda P.B. Katehi, for issuing the order to police to clear the quad of student protesters. In an open letter, he described the force (some of which you don't see in the video) used by police against the students, peacefully protesting in solidarity with the Occupy movement:

Without any provocation whatsoever, other than the bodies of these students sitting where they were on the ground, with their arms linked, police pepper-sprayed students. Students remained on the ground, now writhing in pain, with their arms linked.

What happened next?

Police used batons to try to push the students apart. Those they could separate, they arrested, kneeling on their bodies and pushing their heads into the ground. Those they could not separate, they pepper-sprayed directly in the face, holding these students as they did so. When students covered their eyes with their clothing, police forced open their mouths and pepper-sprayed down their throats. Several of these students were hospitalized. Others are seriously injured. One of them, forty-five minutes after being pepper-sprayed down his throat, was still coughing up blood.

According to guidelines [PDF] for all California State schools, pepper spray is meant to be used for no more than one second on any one person. "[It] is to be sprayed in a one-second burst. It is not meant to be used repeatedly on an individual, or for long periods of time," advise the authors. At U.C. Davis, police did not attempt to minimize students' exposure; in fact, the police officer captured on video (Lt. John Pike, who has since been put on administrative leave, along with one other officer and police chief Annette Spicuzza) delivers prolonged and direct streams of OC spray to individual protesters and even returns to some, spraying them more than once.

Given that protesters are out in force and so are the police, here are some tips for surviving a pepper-spray attack:

Don't rub your face. Pepper spray inflames the capillaries on your skin's surface, which is what causes the intense burning sensation. When you touch the affected area, you are further helping to open up capillaries, which will make the pain worse.

Try not to breathe it in. Inhalation is the real danger, so the more you can cover your mouth and nose, the better.

Be careful of cold temperatures. You should flush any area that's been pepper-sprayed with cool, fresh water and stand in front of a fan — a fresh-air breeze helps. But given that capsaicin stimulates heat receptors, which in turn triggers the body's cooling response, overexposure to cold water can be dangerous in winter weather. "This dual effect increases the risk of hypothermia if victims are decontaminated with cold water on cold days," wrote the authors of the 2004 paper.

Use the right soap. Clean affected areas with non-oil or cold cream-based soap. Don't use salves or greasy ointments because they will trap OC resin to the skin. And remove any affected clothes or contact lenses.

Don't resist arrest. Half of the 26 deaths linked to pepper-spray use by California police, reported in the 1995 ACLU report, occurred in victims who were restrained using the "hog-tie" method. The more you resist, the greater your danger of getting excessively sprayed and of being restrained in an extreme fashion. "In half of all cases, the types of police restraint techniques used were identified as contributing to the cause of death or the primary cause of death," wrote the reports authors.

Make your health problems public. If you have asthma or a heart condition, let someone know, so they can help you get the right medical attention right away. Sixty-one percent of the victims in the UCLA report showed evidence of an underlying heart or respiratory disease and two people had asthma, suggesting that pepper spray may be particularly dangerous for these people.

Meredith Melnick is a reporter at TIME. Find her on Twitter at @MeredithCM. You can also continue the discussion on TIME's Facebook page and on Twitter at @TIME.

Read more: http://healthland.time.com/2011/11/22/how-painful-is-pepper-spray/#ixzz1eTULYHKW