On Saturday morning, the Pittsburgh Bureau of Police, Fire, and EMS all reported to a 911 call for a fire on the 70 block of Cust Street in Hazelwood.
The call came in around 2:15 a.m.
When first responders arrived, they saw flames coming out of an empty home.
The response initially started as a two-alarm fire, but it was upgraded to four alarms after the first responders' arrival.
Two adjacent homes also caught fire, but all three occupants were able to evacuate safely.
After two hours, the fire was reported to have been under control.
Red Cross will be assisting those who were displaced.
The cause of the fire is undergoing investigation by the Fire Investigation Unit.