MONTREAL -- Investigators from the federal Transportation Safety Board are at Trudeau airport following a fire on the tarmac that led to a number of injuries.

The fire broke out Monday afternoon when a Royal Air Maroc plane arrived from Casablanca.

As airport personnel were taking baggage out of the plane's cargo hold, the conveyer belt vehicle caught fire, enveloping the plane in smoke and sending choking clouds through the plane's open cargo doors.

With 250 passengers still aboard, the crew ordered an evacuation, popping the emergency doors and sending passengers sliding down the ramps to the tarmac.

“We felt it hot, because we were close to the fire,” said passenger Omar El Khattat, who took a video of the event. He said the scene was frightening; he knew something was wrong after the plane landed, but passengers only realized what was going on once they safely de-planed.

On videos taken by Lee Brown and Antonio Molina, passengers, some holding carry-on luggage, can be seen sliding down the emergency chutes and walking away from the airplane. Some stumble and trip upon hitting the ground, and several people suffered lower body injuries during the evacuation. Seven people were treated for smoke inhalation at the scene, and five went to hospital for further treatment.

Ricardo Hernandez was refueling another plane a short distance away when he spotted the fire. He and other airport workers rushed to the aid of passengers who were running around in a near panic.

"There were people running everywhere, lost. We didn't know what to do. We're talking about 200 passengers," said Hernandez.

The situation was very dangerous, he said.

"We're talking about fire beside a plane. That plane probably lands with 6,000 kilos of fuel," said Hernandez. “That’s a lot of fuel.”

He and other workers got the passengers to a safe spot and kept them secure until they were taken into the airport.

The Boeing 767 remained grounded Tuesday, although it was not damaged by fire.

The TSB will determine the cause of the fire, and determine if similar events can be avoided in the future.

“It was easy to determine that it was due to a fuel leak within the engine compartment (of the baggage coveyer),” said TSB investigator Jean-Marc Ledoux.

Ledoux said the ground service company Servisair is inspecting its equipment.

The TSB has no record of any event like this so far.