FORT PIERRE, S.D. – The investigation into a fatal house explosion in Stanley County in May is continuing, but authorities have ruled the explosion an accident.
In a release from the Stanley County Sheriff’s Office to social media Wednesday it’s believed the explosion was caused by propane gas accumulating in the basement of the Trevor and Kelsey Hupp residence.
Damaged piping and components of the propane gas delivery system in the home are still undergoing lab examinations.
The investigation of the explosion will continue, pending the lab’s analysis of the home’s fuel system.
The investigation has not determined an ignition source of the explosion.
The May 24th explosion killed Bill and LaDonna Hupp of Huron and their granddaughter Harper.
The State Fire Marshal’s Office, Division of Criminal Investigation, Highway Patrol, Stanley County Sheriff’s Office and Fort Pierre Fire Department all assisted in the investigation of the explosion.