The Calgary bus fire that killed three people on Thursday afternoon has left a city in shock and a lot of people asking how a routine commute turned into the worst collision scene one veteran officer has ever worked. According to the Calgary Herald, three people are dead and many more are hurt after a chain-reaction crash in the northeast community of Saddle Ridge.

What happened on Saddletowne Circle

Police say crews were called shortly after one in the afternoon to the eight-hundred block of Saddletowne Circle N.E. for a vehicle fire. What they found was a crash involving eight vehicles, including two City of Calgary Transit buses, according to the Globe and Mail. Traffic Sgt. Andy Woodward told reporters that early indications show a northbound bus collided with a white car, which set off the chain of events.

That car hit another vehicle and then a cube van, while the bus kept going, rolled through the intersection and slammed into a second bus sitting at a stop. The impact shoved that second bus across the road and into three more vehicles. Flames quickly swallowed the roof of one bus, sending thick black smoke over the neighbourhood, as reported by the Associated Press at AP News.

The human toll

Woodward said the three people who died were all on the burning bus. "On arrival, the bus was still on fire and we have had three deceased people on that bus," he said, per the Calgary Herald, adding that it was the largest collision scene he has attended in thirty-six years on the force. Thirteen people were aboard that bus when it caught fire.

Emergency medical services spokesperson Adam Loria said paramedics attended to nineteen people in total, and ten were taken to hospital by ambulance. One person was in life-threatening condition, while nine had non-life-threatening injuries. A few more walking wounded were assessed and some were taken to hospital on a city bus. A female police officer was also hurt after running toward the burning bus, though her injuries were believed to be minor.

Why the fire spread so fast

The bus that went up in flames ran on natural gas. Fire Chief Steve Dongworth said crews pulled the driver out, who had taken fairly serious injuries, and immediately called in hazardous materials teams. "We wanted someone to secure those gas tanks on the bus and make sure that was made safe," he said. Crews were able to put out the flames fairly quickly.

The Herald notes that the bus is one of two hundred forty-six compressed natural gas buses in the city's fleet, according to Calgary Transit. Police said the fuel is believed to have caused the fire, per the AP. What investigators still do not know is why the first bus left its lane of travel in the first place. Collision reconstruction teams are collecting video footage from the area to piece it together.

Workers, politicians and a city reacting

Mike Mahar, president of Amalgamated Transit Union Local five-eighty-three, called the scene unprecedented. "It's shocking, the level of tragedy . . . I don't recall a bus burning like that," he said. The union has never had safety concerns about natural gas buses, he said, but "we may now."

Mayor Jeromy Farkas promised a full investigation into what caused the collision and "what may need to change to prevent another tragedy." Premier Danielle Smith thanked first responders who were on scene within minutes, and Prime Minister Mark Carney, who was in Calgary for a rally that day, told families that Canadians are "holding you close in our hearts."

What to watch next

The Calgary bus fire is already one of the most serious transit incidents the city has seen, and the union leader's comments suggest the conversation about fuel safety is only starting. Roads around the scene stayed closed for hours on Thursday, and northbound Saddletowne Circle between Falconbridge Boulevard and Taravista Drive reopened shortly before six in the evening, while the rest of the street stayed shut.

The big open questions are simple. Why did the first bus collide with that white car, was there a mechanical or medical issue, and should Calgary rethink how it handles natural gas vehicles after a crash? Officials have not answered any of that yet, and the cause of the fire is still under investigation, according to the City of Calgary newsroom.

For anyone who rides transit every day, this is the kind of story that sticks. Buses are meant to be the safe, boring option, and one afternoon on a busy street changed that for a lot of people. Expect updates as police release the names of the victims and the investigation moves forward. Follow more of our Canada coverage as details come in.