The cause of a fire early Tuesday morning at a seniors complex in Dryden is under investigation by the Dryden Fire Service.

Firefighters were dispatched to a multi-unit structure fire around 4:30 a.m.

Upon arrival crews reported heavy smoke pouring out of a single unit on the main floor of the building, smoke ended up filtering through the entire structure, requiring an evacuation.

Fortunately, the fire was contained to one unit and extinguished quickly.

Air monitoring and ventilation were set up to clear the smoke from the building.

Two residents were treated by paramedics for smoke inhalation, and the remaining residents were assisted back to their units two hours after the initial response.