(Portland, OR) -- A 66-year-old man was killed in a house fire Monday morning in Portland. Neighbors called 911 after hearing an explosion at a home in the Gateway area. Firefighters found flames coming from a front corner of the house. The victim was found in the room where the fire started and was partially covered with furniture. An oxygen bottled in the room had exploded. The cause of the explosion remains under investigation. Another person in the house was hospitalized with minor burn injuries and smoke inhalation.