Pittsburgh, PA- The Pittsburgh Bureau of Fire responded to a residential structure fire on Ligonier Street in Lower Lawrenceville that rapidly escalated to three alarms, bringing a heavy multi-unit response to the scene.

Two occupants were inside the home where the fire is believed to have originated. One male resident escaped through the upper level and was rescued from a neighboring structure by firefighters using a ladder truck, suffering burn injuries. A second resident was transported in stable condition after experiencing smoke inhalation.

Fire conditions extended to an adjacent structure, causing significant damage, though it was unoccupied at the time.

During operations, a mayday was transmitted after a floor collapse occurred inside one of the involved structures.

Firefighters were able to account for all personnel, and no injuries were reported from the collapse.

Two firefighters sustained injuries during the incident and were transported in stable condition for evaluation and treatment.

Fire investigators are working to determine the cause of the blaze. Displaced residents are receiving assistance from the American Red Cross Greater Pennsylvania, while Salvation Army Emergency Disaster Services provided on-scene support to both responders and those affected.