NISLAND, S.D. (AP) -- A house explosion north of Nisland was probably caused by leaking gas sparked by an electric pump, investigators concluded.
The explosion Sunday night blew out the first-floor walls and caused the second floor to collapse on Bill Anderson.
Anderson, 45, was listed in fair condition at a Rapid City hospital.
His teenage daughter escaped through the roof with minor injuries. His wife, Diane Anderson, was not home at the time of the explosion.
Butte County Sheriff Fred Lamphere said Tuesday that investigators from the South Dakota Fire Marshal's office determined that a cistern water pump turned on when Bill Anderson turned on the bathroom sink.
The spark from the pump's motor ignited propane that was leaking from a valve under the house.
The resulting blast did not cause a fire, but most of the Andersons' personal belongings were destroyed.
The house was not insured. Anderson's employer is planning a benefit auction to help the family recover some of its losses.
