Four people, including two children, were hospitalized after an early morning apartment fire in downtown Toronto on Tuesday.

The fire broke out shortly after 3 a.m. in an eighth-floor unit of a high-rise on Ontario Street. Toronto Fire crews quickly brought the blaze under control, though significant damage was visible to the unit’s exterior.

A man was admitted to hospital with second-degree burns, while a woman and two children, ages 12 and 14, were taken to hospital for observation. Several other residents received treatment at the scene for smoke inhalation. All reported injuries are considered non-life-threatening.

Fire officials are investigating the cause of the blaze. E-bikes were found on the unit’s balcony, with lithium-ion batteries located inside, though investigators have not confirmed whether they played a role in the fire. Officials also noted that the unit’s smoke alarms were functioning and reminded residents to use only manufacturer-approved lithium-ion batteries for their devices.

The fire is not considered suspicious, and police are not involved in the investigation. While the family living in the affected unit has been displaced, all other residents have been allowed to return to their homes.