The Kansas State Fire Marshal's Office says an explosion that killed six people at a grain elevator in northeast Kansas was accidental.
The agency released its preliminary findings Thursday.
It says it found no evidence of criminal activity in the Oct. 29 grain dust explosion at the Bartlett Grain Co. elevator in Atchison, about 50 miles northwest of Kansas City.
Preliminary findings indicate the blast apparently originated in the elevator's main bin area.
The investigation is ongoing.
Rose Rozmiarek, the chief of investigations for the Fire Marshal's Office, said in a telephone interview that grain dust was definitely the fuel that was ignited. She says investigators are still trying to determine what sparked the dust.
The explosion killed four Bartlett employees and two grain inspectors. Two other people were injured.