Halifax firefighters got a surprise Thursday morning when flames started shooting from their own truck as they responded to a call.

"Unbelievable -- a fire truck actually caught on fire," mused Deputy Fire Chief Roy Hollett.

"It's like a police car getting broken into."

Hollett said the truck was responding to a medical call in Lake Echo, about 26 kilometres east of downtown Halifax, at about 9 a.m. when it began to lose power and started making loud noises.

"As (the driver) stopped the truck, the cab started to fill up with smoke. The captain directed everyone to get out immediately. When they got out, they noticed there was smoke and fire under the wheel well and the cab."

He said four people were in the truck, a 2003 Pierce. Some of the firefighters suffered minor smoke inhalation, but nothing that required medical attention, Hollett said.

Crews quickly brought breathing apparatus and other equipment to safety, and then lifted the cab to attack the fire. They used an extinguisher to contain it to the engine itself, before a second truck put the fire out, he said.

Hollett said it appeared some grease or oil on top of the engine was burning, and oily spots were seen on the ground nearby on West Porters Lake Road. The cause is under investigation.

"We've had two fire stations catch fire ... but fire trucks catching fire, I don't recall and I've been with Halifax fire almost 18 years," Hollett said.

"There's a degree of irony, yes. When I heard the call come in on the radio, and heard an engine fire, I figured it was a car fire. And when the dispatcher confirmed the address and said it was a fire truck on fire, I slowed down and turned the radio up and thought, OK, did I actually hear a fire truck on fire?"

"So I made my way there ... Thankfully, no one was hurt and I can laugh at it now."

Another truck continued to the medical call, while a spare truck picked up the stricken truck's equipment and took over its duties.

City spokesman Brendan Elliott said the road was shut down for three hours.

"The truck was towed to our in-house mechanical garage, where it will be assessed and if it looks like we can't fix it ourselves we'll bring someone in to help us," said Elliott.