Officials say the fire broke out shortly after 6 a.m. Thursday in an upstairs apartment of a two-unit house on Riverview Street.
Waterville Fire Capt. David Lafountain says firefighters rescued 28-year-old Craig Sargent and his 2-year-old son, Matthew. They found 23-year-old Amber Mitchell in a back bedroom, and she was pronounced dead at Maine General Hospital.
Public safety spokesman Steve McCausland says Sargent and his son were taken to St. Mary’s Hospital in Lewiston, where they are being treated for smoke inhalation.
According to McCausland, investigators said the fire started in the living room and was most likely caused by careless of disposal of smoking materials. He says a battery-operated smoke detector had been removed and was found in a kitchen drawer.