A kitchen fire reported by a passerby at 4:33 p.m. in the 500 block of 4th Avenue South in Kent has displaced two adults and two children, according to the Kent Fire Department.
An adult and two children were home at the time, but were not inside, officials said. A pet cat has not been accounted for.
Investigators said the blaze started when unattended cooking oil overheated in the complex, which is operated by King County Housing and the YWCA.
The flames extensively damaged the kitchen and dining room of the single story apartment, but crews kept it from spreading to the attic or other units, officials said.
The people displaced are being helped by the American Red Cross.