Photograph by Victor R. Caivano, AP Images

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A photo of a Brazilian woman being pepper-sprayed in Rio de Janeiro has sparked controversy over its use on protesters.

Photograph by Victor R. Caivano, AP Images

Brazil Pepper-Spray Photo Highlights Exposure Risks

After a woman is subdued during protests, the use of force raises questions.

The Internet is buzzing over a photo of a woman getting sprayed in the face at close range with what appears to be pepper spray by a riot police officer in Rio de Janeiro (see above). The photo was reportedly taken on Monday, amid mass demonstrations in the city.

Local police say 100,000 people had gathered in the streets of Rio de Janeiro, building on big protests in Sao Paulo and other Brazilian cities this week. Protesters say they're angry over a lack of public services, economic instability, government corruption, and police brutality. (See "Playing Rio.")

Much of the online conversation around the photo has been marked by shock and revulsion. "It seems that the most dangerous thing the woman is carrying," wrote Business Insider, "is a cigarette."

The photographer who shot the picture, Victor Caivano, told New York magazine that the woman in the shot was standing alone at around 11:20 p.m. on a "deserted corner" after the police had cleared the area of rioters.

"Three riot officers approached the woman and told her to leave," Caivano said. "When she resisted—the woman either questioned the order or insisted that she wasn't doing anything wrong—she was pepper-sprayed. This policeman just didn't think twice."

The photograph has invoked pepper-spray outrage. So what exactly is the stuff?

Sven-Eric Jordt, a professor of pharmacology at Yale University School of Medicine who studies the effects of pepper spray and tear gas, says the active ingredient in pepper spray is capsaicin, the highly pungent natural chemical in chili pepper oil.

It's vaporized into an aerosol for use, with spray cans designed for use at close range. For those hit with it, the capsaicin activates pain receptors in the body—receptors that Jordt and his colleagues discovered in the early 2000s.

The activation of these receptors is what gives spicy food its kick, said Jordt, although usually the level of exposure is a lot less than getting sprayed.

The Impacts of Pepper Spray

Asked what it would feel like to be hit with pepper spray in the face, Jordt said, "Immediately you will be very irritated by the physical exposure of the spray, and after a half second or one second you will experience excruciating pain that persists for quite some time, especially in the eyes, nasal passages, and mouth.

"You will probably get an involuntary closing of the eyes, massive tear secretion, your nose will run, and you will get clogged up," he continued. "If you don't wash it off immediately you will get swelling, skin burning, and maybe blistering."

Jordt said that inhaling pepper spray can cause coughing and choking, while inhaling a large amount can cause fluid to build up in the lungs. That can lead to shortness of breath, he said.

People with asthma or allergies, or lung issues such as emphysema, "could be in great peril," Jordt said, even in danger of losing their lives.

He pointed to a legal report to the U.S. Marine Command, which stated that pepper spray "can cause respiratory failure in susceptible individuals," and to a North Carolina Medical Journal article on the hazards of pepper-spray exposures, with examples of lethal or almost lethal consequences.

Jordt said that the symptoms of contact with pepper spray can last for days or weeks, especially in those who have underlying conditions. He's not aware of documented long-term effects of pepper spray in the medical literature, though he has heard of victims who have alleged detrimental effects.

How Safe?

Asked whether he thinks pepper spray should be legal for use, Jordt said, "The police think this is a proportional response that is nonlethal that may not have long-term consequences, but persons with respiratory conditions such as asthma may be in great danger when exposed."

"That looks pretty terrifying," he said of the viral photo out of Brazil. "She could be my mom or your mom... though you never know the situation."

National Geographic reached out to Rio de Janeiro's military police, who are responsible for keeping order during riots, but has not heard back.

Jordt said the viral Brazil photo reminded him of photos that circulated in November 2011, after peaceful protesters were pepper-sprayed at the University of California, Davis. The university later settled with the affected students for about $1 million.

The photo may also call to mind the case of the "Q-Tip Pepper Spray Eight." In 2005, a federal jury found Humboldt County and the city of Eureka, both in California, liable for "excessive force in violation of the 4th Amendment to the U.S. Constitution," according to the defendants' website.

"Humboldt County Sheriff's Deputies and Eureka Police Officers used unconstitutional excessive force when they applied pepper spray with Q-tips directly to the eyes of the eight nonviolent forest defense protesters in three incidents in 1997," the site says.

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