A U.S. National Guardsman washes pepper spray from his eyes during a training exercise. It works by inflaming the membranes in the nose, throat and lungs. (Stephen Morton/Associated Press)

Police and pepper spray have become a volatile mix in Canada ever since the RCMP used the weapon on a group of university students in 1997, at a gathering of international leaders in Vancouver.

That incident burned itself into public memory because the use of pepper spray seemed excessive. It also sparked 52 complaints against the RCMP and a lengthy inquiry.

Video footage of the confrontation shows an officer telling students to move, then showering them madly with pepper spray just moments later. The scene is chaotic. There is much pushing and shoving between police and protesters. One student covers his eyes in pain. Another is shown spitting it out. The spray is eventually shot at the camera, covering the lens.

Afterwards, then prime minister Jean Chrétien joked about the incident, saying: "For me, pepper, I put it on my plate."

But for many, the matter was no joke. The inquiry by the RCMP Public Complaints Commission concluded that the use of pepper spray by at least one officer, Staff Sgt. Hugh Stewart, was unnecessary and could not be justified. Stewart was given the nickname Sgt. Pepper.

However, while the inquiry assessed RCMP conduct in policing the APEC (Asia-Pacific Economic Cooperation) summit, it never recommended that the force review its policy on the use of pepper spray when dealing with dissent. Now, 10 years later, questions persist about the substance, particularly in light of the most recent incident earlier this month involving a group of native people celebrating a kids' soccer game at Sechelt, B.C.

This time, it was a home video of the incident that sparked outrage and forced the RCMP to apologize.

The Union of B.C. Indian Chiefs said in a statement: "There is no possible excuse for pepper-spraying babies and small children. No excuse whatsoever!" But apart from that, civil liberties groups say pepper spray may not be as safe a weapon as police like to think it is, nor is it always the most appropriate tool to curb protests.

How it works

The RCMP was one of the first Canadian forces to use pepper spray in 1992 for crowd control. It is considered a non-lethal weapon and was part of a movement by police forces at that time, particularly in the U.S., to find alternatives to the use of guns. Stun guns or Tasers came along in tandem and were adopted by several Canadian police forces later in the decade.

The RCMP prefers to call pepper spray OC spray, which stands for oleoresin capsicum. It's a derivative of pepper plants and the main active ingredient is capsaicin. All RCMP officers carry it in canisters. Pepper spray is deemed by the force to be "one of many response options." When sprayed directly in the eyes or on skin, it burns.

The burning sensation, however, does not always have the desired effect. The RCMP admits that some subjects run away, while others become enraged.

People subjected to pepper spray have said it feels like torture. It causes coughing, a runny nose, gagging, shortness of breath, and can lead to momentary blindness. It works by inflaming the membranes of the nose, throat and lungs. Eyes swell and can seal shut. Effects can last for up to 45 minutes.

There have been reports of people who have died in police custody after being pepper sprayed — though not in Canada. But according to Sgt. Richard Groulx, a national training coordinator for the RCMP in Ottawa, there is no direct medical proof that the spray itself actually causes death. He believes the problems stem more from pre-existing conditions, such as asthma.

The California branch of the American Civil Liberties Union, however, has linked pepper spray directly to 27 deaths in that state alone in the early 1990s. And some U.S. newspapers have come up with higher totals from time to time.

One of the legal ironies of pepper spray is that it appears to be outlawed for international use in war by the 1972 convention on biological weapons but not for internal use by countries for security. However, use of pepper spray by the public is widely restricted around the world.

Legal status

Originally developed as a bear repellent, pepper spray has had a number of uses over the years. It can be bought over the internet, and has been used by criminals to invade homes and rob convenience stores, by letter carriers to repel snarling dogs, by women to discourage rapists and by campers and hikers to fend off aggressive bears.

Legally, it is considered a prohibited weapon in Canada. The Criminal Code says that a prohibited weapon is "any device designed to be used for the purpose of injuring, immobilizing or otherwise incapacitating any person" and specifically refers to such products as "tear gas, Mace, other gas, and any liquid, spray, powder or other substance that is capable of injuring, immobilizing or otherwise incapacitating any person."

Proposed regulations were drafted and published in the Canada Gazette in 1998 to clarify the legal status of pepper spray. They stated clearly that it would be illegal to sell pepper spray for use against people, but when marketed strictly as a wild animal repellent, the sale would be allowed. The regulations have not yet been adopted, which adds to the confusion over the legal status of the substance.

At least two hunting stores in Toronto, contacted by CBCNews.ca, said they sold the product but only as an animal repellent. One required potential buyers to sign a waiver saying they wouldn't use it on humans.

Mountie policy

According to RCMP policy, all officers are required to carry a can of pepper spray and to be trained in its use. Groulx, who has been sprayed many times himself, says officers are taught how to use the spray and, most importantly, how to assess a situation to determine which of their tools, including pepper spray, should be deployed.

Groulx trains RCMP instructors who in turn train rank-and-file officers across the country in the use of pepper spray. "It's one of many responses," he says.

RCMP officers have a variety of weapons at their disposal: a 9 mm Smith & Wesson pistol, a baton, handcuffs, plus pepper spray. "When you are on duty," Groulx says, "you must carry all intervention options." If properly trained, officers can also use Tasers, or stun guns. But not all officers are trained in the use of these so-called conducted energy weapons.

Pepper spray is used only when a subject is actively resisting an officer, combative, or has the potential to cause death or grievous bodily harm. It is not supposed to be deployed on someone an officer considers to be merely non co-operative.

"Every time a police officer responds to a situation, he is required by duty to perform a risk and threat assessment, " Groulx says. "He must choose the option least injurious to his client and himself."

That assessment involves deciding the behaviour of the subject and looking at "situational factors," which can include the number of people involved, the size of the person and the surrounding environment as well as the number of possible weapons or bystanders in the vicinity. Behaviour means whether someone is co-operative, non co-operative, resistant, combative, or potentially dangerous.

A preferred option

Groulx said, despite controversy, pepper spray is preferred to what the RCMP calls "empty hand techniques," which include responses such as punching, hitting and kicking. Such methods cause injury to both parties.

But pepper spray takes a while to work. "It doesn't control the client immediately. A client who has been sprayed can fight viciously for over a minute. Some people are not affected by pepper spray. Yes, it will likely affect the client, but does not control the client immediately," Groulx says.

The Taser, on the other hand, stops a person in his or her tracks, causing them to drop to the ground. But if there are many people attacking the officer, a Taser is not considered ideal.

RCMP officers are trained not to use pepper spray on open eyes for long periods of time. Instead, they are taught to spray for up to one and a half seconds only in a circular fashion. Spraying at an open eye for several seconds can cause serious eye damage.

Groulx said the RCMP currently does not keep statistics on the use of pepper spray, but such record keeping is being actively considered. The force does keep track of Taser use, however.

For activists, pepper spray is far too commonplace a tool used by police to keep legitimate protests at bay. Even human rights group Amnesty International is concerned about its use: "Because of the great risks associated with pepper spray," it says, "its use must be questionable in any circumstances."