Three families were displaced Sunday night when a fire damaged an apartment unit in Kent.

Kent firefighters were called to the 23800 block of 30th Avenue South  about 11:30 p.m. Sunday. They found heavy smoke and flames coming from a third-floor apartment, the Kent Fire Department reported.

Crews doused the flames before they were able to spread.

Residents of the apartment where the fire started had been asleep inside at the time. They escaped and narrowly avoided being seriously injured, firefighters reported.

The contents of their apartment were a complete loss. Other apartments suffered water damage, displacing their tenants.

American Red Cross volunteers responded to help the displaced families. The apartment management staff provided one of the three displaced families with an apartment to stay at, firefighters reported.

Crews were investigating what started the fire.