(WDTN) — Wednesday was a tragic day for Philadelphia after 12 people died in a row house fire. Firefighters are still trying to figure out what initially caused the fire, but they did determine the flames spread quickly.

Riverside Fire Chief Daniel Stitzel said it can be easy for flames to spread throughout your home.

“Fire can spread so rapidly. Especially with the light fuels, the plastics we have in our homes today. When those things start to burn, those things burn so rapid and so hot,” Chief Stitzel explained.

Investigators also determined the smoke detectors in the row house did not work. Chief Stitzel said it is crucial to make sure your smoke detectors are working and in the right place. He recommended one on every level of a house and one in every bedroom.

“Make sure they are in good working order. It’s the early detection. And again, as fire grows so fast, the sooner we find out there is a problem, the sooner we can get out,” Chief Stitzel said.

Cpt. Brad French, the public information officer for the Dayton Fire Department, also recommended coming up with an exit strategy, so when the worst case scenario does happen, you know where to go.

“Very important that everybody knows at least two ways out of every room inside the house and also have a defined meeting place outside the home,” Cpt. French said.

Cpt. French also stressed the importance of closing the bedroom door when you sleep. He said that can slow the flames from spreading into the room while you sleep and slow the spread of smoke.