A number of units on three floors at the Regina General Hospital were evacuated Sunday after reports of heavy smoke in the building.

Fire crews received the call at 1:50 p.m. CST about thick smoke from the third to the fifth floor of the hospital.

The fire department sent six trucks and 24 firefighters to the scene.

Gerald Kay, deputy fire chief, said the smoke wasn't very heavy when they got to the hospital.

Firefighters saw there was a fire alarm going off in the electrical room on the sixth floor, and traced the smoke to a malfunctioning ventilation unit that had overheated.

"I believe it was all smoke,"said Kay. "We can't confirm any fire in that room. It did get up to a high temperature in that room and once we turned off the power, the heat came down to normal levels."

Kay said so many trucks and firefighters were sent because of the possibility that they would have to evacuate large numbers of people from the building.

"It is a concern primarily because of the patients and people aren't able to get out by themselves," he said.  "That requires a lot of staffing to be able to move people."

He added that hospitals are highly compartmentalized and regulated, which makes it easier than other buildings to find out what's happening and where.

Keith Dewar, the CEO of the Regina Qu'Appelle Health Region, said the evacuation wasn't panicked or chaotic, but it was definitely exciting for patients, staff and visitors.

"It was quite impressive actually how both the family and friends of those that were here and staff from other units, porters, pretty well everybody got supported and got involved in moving the patients to their appropriate areas to be marshalled," said Dewar.

He said he's not sure of the number of people that had to be moved, but added that all patients have settled back in their rooms. A number of medical patients, a pediatric area, a psychiatric unit and some administrative offices were in the evacuated areas.

Though some patients with respiratory illnesses were coughing from the smoke, no one was seriously ill in the units that were evacuated. 

Hospital maintenance workers are looking to see if they can put a backup ventilation fan in place, or figure out a way to manage until the hospital gets a replacement.

No injuries were reported.

All visitors were asked to leave the hospital, but have since been allowed back in.