Calls for help around 2 a.m. led to firefighters spotting smoke at a large two-story duplex.
District Chief Lester Flohr said, "We found a moderate amount of fire right inside the front door of the duplex."
Flohr said there were small flames at that front door.
Firefighters doused those flames quickly and discovered the woman living in the downstairs apartment had grabbed her dog and made it safely outside.
The people living in the upstairs apartment were also located away from the home and uninjured.
Firefighters then went inside to knock down the rest of the flames and smoke. That is when they ran into the backdraft and a mini-explosion.
Flohr said, "We don't see that too often, they can be quite deadly to firefighters and you normally see it in a heavier smoke and fire environment than we had here but apparently there were some void spaces in the ceilings and the walls and when those were breached and opened up by the firefighters as they looked for extensions, that's when the smoldering fire caught enough oxygen to explode."
Flohr said the explosion was strong enough to knock a 4 by 10 foot section of drywall down onto the floor.
No firefighters were injured by any of the falling debris.
Flohr said there was some luck involved but that, in addition to that, all Dayton firefighters are trained to read smoke conditions that might lead to, or indicate, a backdraft.
He said, "This was unexpected here, the amount of fire was small, the smoke was moderate but the explosive gases hiddeen in the walls in the void space, that's why we had an event like this, it normally doesn't happen in small fires."
The home has almost no visible damage outside but firefighters said there is quite a bit of damage inside.
Fire officials said they believe the fire started on the front porch of the the duplex as an accident. They do not believe there is anything suspicious about it.