The London Fire Department is urging caution around lithium-ion batteries after a portable charger sparked a fire inside a student’s backpack at Northridge Public School.

Fire crews were called to the northeast London school around midday on Feb. 2 and found a fire on the second floor. Officials say a damaged phone charger had been left unattended while inside a backpack, which led to the incident.

According to Platoon Chief Jamie Britton, the battery ignited and produced flames roughly two feet high. The school’s vice-principal was able to extinguish the fire using a fire extinguisher before firefighters arrived.

No injuries were reported. As a precaution, students were evacuated while crews ensured the fire was fully out and smoke was contained to the second floor. Fire officials noted the situation was quickly identified by staff, allowing for a fast and orderly evacuation, and are reminding the public not to charge lithium-ion batteries unattended or inside enclosed spaces like backpacks.