Preliminary investigation shows Fremont explosion was accidental

A preliminary investigation is calling the explosion that leveled a Fremont manufacturing plant accidental.

The Nebraska State Fire Marshal’s Office said in a news release Thursday afternoon that it believes the blast at Horizon Biofuels was caused by an “accidental dust explosion” that occurred during the manufacturing process.

The explosion Tuesday reduced most of the building to rubble and killed three people.

The Dodge County Sheriff's Office said late Wednesday that 32-year-old Dylan Danielson of Columbus was killed in the explosion along with two young girls. Though the Sheriff’s Office did not name the girls, officials had said earlier that day that the missing people were a Horizon employee and his two daughters, both under the age of 12, who were waiting for him to get off work so he could take them to a doctor’s appointment.

Horizon, which produces wood pellets for pet bedding and other products, was fined $6,000 in 2012 for four violations that were deemed "serious” by the Occupational Safety and Health Administration.

The fire marshal’s office said instability of what remains of the Horizon building is hampering efforts to more thoroughly investigate the cause of the explosion.