Investigators say a house fire in Grinnell early Sunday was caused by a careless smoker. Two of the three people taken to the hospital after the fire have been released. A third person was admitted to Grinnell Regional Medical Center.

The Grinnell Fire Department reports the three had burns and smoke inhalation. Their names were not released. The fire was reported shortly after midnight Sunday. Grinnell Police Officer Jeremy Stevenson was first on the scene and helped everyone out of the house.

The fire started when the home owner fell asleep on the couch while smoking, and medical oxygen contributed to rapid fire growth. Some 22 firefighters were on the scene for over three hours. One firefighter was treated on site after becoming overheated. Damage to the house is estimated at $75,000.