TULSA, Oklahoma -- Tulsa Fire officials ruled Monday's fire at the Lake Apartments accidental.
Investigators believe a discarded cigarette was the likely cause of the fire that damaged several units at the 81st and Riverside apartment complex.
Firefighters said the fire started in a downstairs unit and spread to an upper unit. They said about four to five units sustained fire, smoke, or water damage.
Firefighters said two people were inside the top unit and three people were inside the downstairs unit at the time the fire broke out. No one was injured.
Red Cross assisted those displaced by the fire.