ODESSA - We now know what sparked an apartment fire in Odessa on Saturday.
Investigators are blaming a cigarette.
Officials tell NewsWest 9, a man was smoking while using his oxygen machine.
That sparked the blaze at the Fairgreen Apartment Complex.
Fire officials say the flames didn't do a lot of damage but the fire put out a lot of smoke throughout the building.
One of the tenants was taken to the hospital because of smoke inhalation.