A fire at a Saskatoon recycling centre sent firefighters scrambling Monday afternoon.

The Loraas Recycle facility sorts over 100 tonnes of recyclable material every day. As a result, the building is full of flammable material like paper and cardboard.

When the first fire engines arrived, officials saw heavy smoke pouring out of a large overhead door.

While the cause of the fire remains under investigation, the fire department said it involved cardboard and machinery and "was very difficult to extinguish."

Four fire engines, an aerial ladder truck and a rescue unit were all brought out to put out the fire. It took just over two hours before the fire was brought under control.

The building's sprinkler system went off, and was able to contain the fire until firefighters arrived.

Everyone was out of the building when firefighters arrived. No one was hurt.