Firefighters arrived on scene to find fire shooting through the roof.
It took about 45 firefighters close to an hour to contain the flames, which damaged 75 percent of the building.
Two units are now uninhabitable, and one person is displaced.
The three people who were hurt apparently broke through windows to try and be sure no one was inside the involved apartment prior to the fire department's arrival.
They suffered cuts to their arms and hands, but are expected to make a full recovery.
It turns out no one was in the building at the time of the fire - and the cause was ruled accidental.