A barn that housed a licensed cannabis grow-op in Langley, B.C. went up in flames Saturday night.

Deputy fire chief Bruce Ferguson said his crews first received calls around 10:40 p.m., and arrived to find the large barn completely overtaken by fire.

He said there was nothing left to do to except let it burn and make sure the fire didn't spread.

"We did have some concerns to a farm to the north; it had a barn with animals," he said. "They were concerned their barn was going to catch fire. So we [sent] a crew over."

Luckily, there were no injuries to people or animals. It did take crews more than a dozen hours to douse the flames, and some firefighters were still on scene Sunday afternoon to put out hot spots.

Ferguson said the barn, about 18 metres wide and 100 metres long, used to grow mushrooms but had since been converted into a legal cannabis growth facility licensed by Health Canada.

The investigation into the cause of the fire hasn't been completed yet, but Ferguson said he got the impression it was electrical in nature.

"There have always been inherent risks with grow-ops because of high heat that's generated [and the] electrical installation," he said. "But moreso in the past when they were all illegal and doing the electrical themselves."

The barn was near 256 Street and 48 Avenue, and police closed the road for about a kilometre in either direction overnight while crews fought the flames.