PORTLAND, Ore. -- An apartment fire killed a person in downtown Portland early Wednesday, fire officials said.

Two people were inside the fourth-floor unit at the Bronaugh Apartments at 1434 SW Morrison Street when the flames broke out, according to a statement from Portland Fire & Rescue.

Heavy smoke filled the third and fourth floors, and the building was evacuated. Fire crews said the sprinkler system turned on and firefighters raced inside to quickly extinguish the fire.

The apartments are a HUD facility for elderly and disabled people. Renters said a blind man on oxygen lived in the room along with a stroke victim who smoked.

Fire officials said one of the tenants died in the fire, but a neighbor rescued the roommate. They were then hospitalized to be treated for smoke inhalation.

Portland Fire & Rescue officials said the flames began when a mattress caught fire. There's no word on what caused the mattress to ignite, but neighbors said a cigarette may be to blame.

The identity of the person killed in the fire hasn't been released.

Officials estimate the blaze caused $20,000 in damage.

One Killed In Downtown Apartment Fire