A man and three children were injured after an explosion at a farm near Sigourney Friday afternoon (6/18).  The Keokuk County Sheriff’s Office says it was called just before 4pm to a farm at 18278 Highway 92.  The Sigourney Fire Department and Keokuk County Ambulance responded.  60-year-old Patrick Otte and three children, ages 14, 11 and 8, were all taken to University of Iowa Hospitals and Clinics with severe burns.  No word on their condition.  The State Fire Marshal’s Office, FBI and Keokuk County Sheriff’s Office are investigating the cause of the explosion.