Emergency services say 10 people have been injured, one seriously, at Canadian Forces Base Comox in what the military described as a "significant" explosion.
The blast happened around 9 a.m. PT in an unused barracks building, according to base spokesperson Capt. Brad Little.
According to B.C. Emergency Health Services (BCEHS), several ambulances, including an air ambulance carrying a critical care team, were dispatched to the scene around 9:15 a.m. PT.
In a statement to CBC, BCEHS said six patients were treated at the military base medical unit and three were taken to hospital in stable condition.
One patient in serious condition was airlifted to hospital with the critical care team, said BCEHS, which manages the British Columbia Ambulance Service.
Military officials have yet to say what caused the explosion.
Little said he was in his office across the street when the explosion happened and it was strong enough to cave in part of the office building's ceiling.
He said the blast occurred some distance from where the base's aircraft are situated and there was no damage to aircraft or air field facilities.
Acting Wing Commander Lt.-Col. Mike Juilliet said the explosion happened in an accommodations building that was under renovation, and the building is now heavily damaged.
He said military officials will provide more details at a later briefing, but did not specify when that would be.
"Our focus right now is on assisting our injured personnel," said Juilliet.