A number of patients at a Scarborough-area hospital were briefly evacuated on Wednesday morning after a small fire sent heavy smoke drifting through the building.

The blaze broke out on a food cart located on the third floor of Rouge Valley Centenary Hospital shortly after 9:30 a.m.

Deputy Toronto Fire Chief Jim Jessop said the first crew on scene was met with “significant, heavy, dense smoke” in a portion of the hospital.

The smoke migrated rapidly to other floors, he said, and an evacuation order was put into place.

“The call was immediately elevated to a third alarm to make sure we had sufficient staff attend to assist hospital staff in the evacuation of a number of patients on the third, fourth and second floor, directly above and below the fire,” Jessop told CP24.

Firefighters and hospital staffed safely evacuated an unspecified number of patients from the hospital.

Video from the CTV News Toronto Chopper showed patients lying in hospital beds lined up on a sidewalk outside the facility. Others sat in chairs, draped in white sheets, while they awaited the all-clear to reenter.

Jessop said the fire was extinguished quickly.

“We’re very, very fortunate that we’ve had no injuries,” he said. “That really goes to the training of both the hospital staff and certainly the work done by the women and men of Toronto Fire.”

In a statement, the hospital confirmed that all patients and staff were safe and accounted for but that the third floor Margaret Birch Wing (MBW) has been closed while they assess the damage.

“Patients from the third floor MBW were initially moved to a safe holding area where they could continue to be well cared for. These patients will now be relocated to other areas of the hospital,” the statement reads. “Hospital staff are contacting affected patients’ families and emergency contacts.”

An investigation by Toronto Fire Service’s investigation’s division is now underway.

The Office of the Ontario Fire Marshal has also been notified of the incident.

Jessop said it’s “way too early” to comment on what may have caused the food cart to catch fire.

“We’ll let the investigators do their job and certainly we’ll be sharing any lessons learned with the hospital to avoid any potential reoccurrence,” he said.