Four fire engines and around 25 firefighters were called to a fire at an industrial warehouse on Fountayne Road in Tottenham.
An office on the first floor of a three storey industrial warehouse was destroyed by fire. Firefighters wearing breathing apparatus led one man to safety from the first floor of the building who was taken to hospital.
The Brigade's Fire Investigators believe the fire was caused by an incense stick which fell into a waste bin.
A London Fire Brigade spokesperson said: "Candles, incense and oil burners are one of the most common causes of fire within homes. It’s really important that you never leave these items unattended and keep them away from curtains and anything else that can easily catch fire.
"We advise to place these in a suitable fire resistant candleholder which won’t be knocked over, and make sure you put them out entirely when you leave the room and especially before bed.”
The Brigade was called at 0816 and the fire was under control by 0923. Fire crews from Tottenham and Walthamstow fire stations attended the scene.