A balcony fire at a downtown Toronto high-rise on Monday afternoon has renewed safety concerns about lithium-ion batteries, according to the city’s fire chief.

Crews responded to the building near Wellesley and Parliament streets around 2:30 p.m. Flames were seen engulfing a ninth-floor balcony, sending thick smoke up the side of the building. The fire caused major damage to both the exterior of the structure and the apartment unit where it began.

No injuries were reported. Although the cause is still under investigation, Toronto Fire Services indicated the blaze involved lithium-ion batteries, prompting another warning about their potential hazards.