FRESNO, Calif. (KFSN) -- Firefighters say two adults and two children were inside the duplex on College and Alluvial Avenue when the flames broke out just after 10 a.m.
One of the kids was injured and had a minor burn to his hand.
Fire crews say the flames were quickly able to spread from a bedroom into other parts of the apartment because the family did not notice there was a fire for several minutes.
"They didn't have working smoke detectors in the apartment. That's one thing, especially with small children in the house, the adults were sleeping. The only way they were alerted to it was the smell of smoke and one of the kids screaming," said Fresno Fire Battalion Chief Tim Fulmer.
Firefighters estimate the damage is around $60,000.
The cause of the fire is under investigation and the Red Cross is assisting the family.