The Minnesota state fire marshal's office has ruled the cause of an explosion at a grain elevator in Northrop, MN, last December as accidental.
KEYC reports that 59 fire departments responded to the December 28 explosion.
In the investigation report, the state fire marshal called the incident a dust explosion, with a subsequent fire. Investigators were unable to fully determine what caused the explosion, though a small ticking noise in the equipment could be what created a spark that ignited it.
The fire marshal says that because the ignition source could not be confirmed, the cause will remain listed as undetermined.
