Remembering this spring's Stanley Cup riots in Vancouver can still make many Canadians cringe. The four hours of destruction that rained down on the city stunned the whole country.

But St. Paul's Hospital in Vancouver's downtown had actually had been preparing for them since long before the playoffs began.

On any night of the week, St. Paul's sees its share of injuries from drunks stumbling out of the bars and pubs that fill the downtown. But the hospital rightly suspected that Game 7 would likely bring in more than just a few overly-sauced locals. Many of the hospital staff remembered the 1994 Stanley Cup riots and knew all too well what could go wrong when hockey fans, alcohol and a hot summer night collide.

For each playoff game, as many as 75,000 people had filled the downtown to watch on giant screens. By the time Game 7 rolled around, tension was mounting and hospital staff knew that even with a win, there was going to be trouble.

By 10 p.m. that night, the riots were well underway and the injuries pouring in. But St. Paul's was ready to handle them, says Jeanette Beattie, the hospital's head of emergency preparedness.

Like many large hospitals in Canada, St. Paul's has staff whose sole job is to plan the hospital's response to disasters, manmade or otherwise. At St. Paul's, the woman in charge is Beattie.

She notes that emergency preparedness is a growing industry.

"There are now even university degrees in emergency management. Quite frankly, we're having more natural disaster and more man-made disasters," she says.

Beattie says on the night of the hockey riots, St. Paul's was able to make use of all the training and preparations done ahead of the Vancouver Olympics, when all hospitals across Vancouver had spent months working with police and other first responders about how they would co-ordinate in the event of a terror attack or other disaster.

They had practiced what they'd do by running mock scenario drills. One major exercise they practised involved police, paramedics, and 85 volunteers in full costume and "moulage" makeup pretending to be injured passengers from a plane crash. Beattie says in all, 140 groups took part, learning how to coordinate an efficient response that would allow the injured to be transported and treated quickly.

"That was a huge opportunity for staff to practice their skills in a mock event that was very real to them," says Beattie.

Thankfully, all that worst-case scenario planning never had to be put to use during the Olympics. But it came in handy this spring when it became clear that the Canucks were headed to the playoffs.

"We had a meeting of the hospital's emergency preparedness committee, and in the meeting, we were talking about, OK, if things go sideways, how are we going to decontaminate people if they've been tear-gassed or pepper sprayed? So we had walked through that whole scenario," says Beattie.

On the night of the riots, things started to get ugly around 8 p.m., when spectators started throwing bottles and burning Boston Bruins jerseys. By 10 p.m., there were so many injured pouring into St. Paul's and nearby Vancouver General Hospital, both declared a Code Orange -- hospital code for an influx of mass casualties.

Staff were asked not to go home after their shifts but to help out in the emergency department in whatever way they could. Nine physicians were brought into the ER, instead of the usual two, and more security staff were called in.

A contingent of nurses was assigned to run a pre-arranged decontamination station outside the ER, for the tear gas injuries. They set out garbage bins filled with water so people could dunk their heads to relieve the burning from the gas. The injured were then partially stripped and hosed down to remove the tear-gas powder. By keeping the tear gas injuries outside, staff ensured the ER itself was never contaminated with the powder.

Other staff operated a triage station in a courtyard outside the emergency department to treat those with minor injuries, such as cuts and scrapes. Inside, doctors dealt with the more serious injuries, such as stab wounds, burns, and broken limbs.

Other nurses were also asked to help patients who were having trouble with the psychological impact of the night.

"People really were traumatized. There was the fear, the pepper spray, boyfriends hurt, girlfriends hurt. So we had two psychosocial leads come in," says Beattie.

In all, 147 injured rioters and bystanders headed to St. Paul's ER -- most of them arriving in a two-hour period -- about twice as many as the emergency department typically sees in a night. Only four had to be admitted.

Beattie says the system ran smoothly amid the chaos and pretty much according to plan. The only thing that the hospital had not prepared for was the drifting tear gas.

"Because the tear gas was expelled so close to the hospital, we actually had to shut off our HVAC (air ventilation system). So that put us into a Code Grey, which is air exclusion. And that was on top of the Code Orange of mass casualties," says Beattie.

The Code Grey meant that the hospital's operating rooms were no longer "negative pressure rooms" – a ventilation isolation system that helps prevent contaminated air from escaping from operating rooms and moving through the building.

"Fortunately our OR's weren't in use, but that was something that we didn't anticipate could happen," says Beattie.

That lesson will likely be integrated into the hospital's planning as it gets ready for the next disaster, because as Beattie points out, when it comes to disaster management, "the planning never stops."