More than 500 pigs were killed this morning in an apparent methane gas explosion this morning at a confinement facility near Epworth. It happened about nine at the Anstoetter farm west of Epworth. Gary Anstoetter, who was cleaning stalls in the confinement at the time, escaped unharmed. Fire departments came from Epworth, Centralia, Farley and Dyersville. Investigators think the blast happened when a buildup of methane reached a pilot light on a heater in the building. Damage is estimated at 85-thousand dollars. Firefighters remained on the scene for more than 4 hours.