The use of tear gas, pepper spray, guns and physical restraint is on the rise in Canada’s prisons to defuse violence — an upward trend linked to a more aggressive, gang-affiliated inmate population and overcrowded conditions.

Documents obtained by CBC News Network's Power & Politics under Access to Information show security incidents where use of force was applied against federal offenders have increased by 37 per cent in the last five years — to 1,339 in 2011-12 from 975 incidents in 2007-08.

Records also reveal an increased use of tear gas and pepper spray to stop acts of violence or self-harm; use of tear gas nearly tripled to 292 times from 96 five years ago, while use of pepper spray more than doubled to 400 last year from 186 five years ago.

Although the use of firearms is far less frequent, it also increased — to 32 incidents last year from 24 five years earlier.

The number of incidents requiring use of force rose most sharply in the Prairies, where cases more than doubled to 394 in the last fiscal year — up from 185 five years ago.

The Union of Canadian Correctional Officers representative for the region, Kevin Grabowsky, says the proliferation of gangs and a decrease in available work and programs have combined with overcrowding to make a "very bad mix" behind bars.

"Definitely the overcrowding is starting to take its toll in the Prairies," he said.

According to figures provided by Corrections Canada, the percentage of prisoners double-bunked has climbed to 17.4 per cent nationally, up from 9.6 per cent five years ago. Overcrowding is most acute in the Prairies, where 26 per cent of inmates are now double-bunked — up from 11.8 per cent five years ago.

"Double-bunking has never been a good thing … now you have people with gang ties, anger management problems, violence.… everything that won them a trip to the Correctional Service," he said. "And now you house them in a small area and tell them to get along. It just builds and builds and builds."

Grabowsky points to the maximum-security Edmonton Institution as an example; the facility built for 192 now houses 300 inmates. Incidents across the region range from inmate brawls to attacks on officers and other staff, to riots and hostage-taking — and he sees it as the tip of the iceberg as federal criminal justice legislation fully takes hold.

"I don’t see anywhere on the horizon a break in what’s happening," he said.

Concerns about double-bunking

All of this raises concerns for officials not just about institutional safety — but about the effect on public safety, as most inmates will eventually be released from the hostile environments.

"I think it means we’re not going to be putting out a very good inmate," he said. "It doesn't make for good public safety."

Correctional Investigator Howard Sapers said that while bed space may not be the direct cause of increased violence, there is definitely a relationship.

He said his office is disturbed by the increase in use of force, as well as the rise in assaults and homicides in prisons.

The federal watchdog said overcrowding leads to a number of problems — from lack of work to access to programs in penitentiaries.

"Crowding into itself creates a constellation of issues — and double-bunking is one of them," Sapers said.

Conservative MP Kerry-Lynne Findlay, parliamentary secretary to the minister of justice, says prison violence and double-bunking are two separate issues.

"Double-bunking is something that is used world-wide and in Canada we only use it … when it is safe and appropriate to do so," Findlay told Power & Politics host Evan Solomon Wednesday.

The increase in prison violence is the result of more violent criminals being taken off the streets, Findlay said.

"We attribute it to our tough-on-crime measures over the last six years that have kept more violent and serious offenders behind bars and off the streets, which is a good thing for law-abiding Canadians, but what it does mean within the correctional system is that we do have more young offenders, more gang members, and in some instances some increase in those with mental illness problems, and that is why you see that increase [in violence]."

Sara Parkes, spokeswoman for Corrections Canada, said the anticipated increase in offender population from recent legislation did not materialize, but that officials are closely monitoring the situation and will respond accordingly.

While many worry about an added strain on the system, she said officials are also making contingency plans to accommodate inmates displaced from the closure of Kingston Penitentiary, Ontario's Regional Treatment Centre and Leclerc Institution in Laval, Que. — all planned for decommissioning by 2014-15.

As for the rise in use of force, Corrections Canada points to a changing offender profile and incidents at mental health treatment centres for the increased interventions.

"The profile of offenders entering CSC institutions has become more complex and diverse in recent years, including a younger inmate demographic, more inmates being assessed as having mental illnesses or being involved with organized crime," Parkes said.