The fire raced through a grocery store in the 1500 block of 9th Street in Oakland. One person was injured.
Officials are determining whether there were explosives involved. Oakland firefighters and investigators are out sifting through debris.
Firefighters are pretty sure that the fire started with an explosion, but now the question is what caused it.
The flames started shooting at around 3:00 a.m. on Thursday morning and it took fire officials about 45 minutes to get it controlled.
Residents in the area say they all heard a loud explosion, and a store employee was sleeping in the back of the store and he says he was barely able to escape.
"I was panicking so much and then we pulled the doors open and finally got open and he went and there was like a milk crate, I tripped and broke my nose," said store employee Fares Gassaley.
"It just kept going like firecrackers but like explosions over and over again," said neighbor Andrea Hubert.
Those who witnessed those loud explosions and the way the wall collapsed on the store leads them to believe that this was definitely an explosion.
The employee that was interviewed said he broke his nose. He also suffered smoke inhalations, and another guy who was in the apartment with him also suffered smoke inhalations.
They were both released from the hospital.