Didion Milling Company Explosion and Fire

At approximately 11:00 PM on May 31, 2017, explosion(s)1 at the Didion Milling (Didion) facility in Cambria, Wisconsin, resulted in 5 worker deaths and an additional 14 workers injured. Because the event occurred at night, only 19 employees were working within the facility at the time of the incident.2 Shortly before the explosion(s) at Didion, workers saw or smelled smoke on the first floor of one of the mill buildings. In trying to find its source, workers focused on a piece of equipment called a gap mill.3 While inspecting the equipment, workers witnessed a filter connected to an air intake line for the the mill blow off, resulting in corn dust filling the air, and flames shooting from the air intake line, followed by one or more explosions. After the CSB’s initial assessment on site, the agency mobilized additional investigators, structural and blast engineers with expertise in dust explosions, and a drone team to enhance its field capabilities. The CSB and its contractors conducted limited entries into a number of the mill buildings4 and completed ground and elevated surveys of the blast damage in an effort to determine the origins of the event and the possible contributing role of the dust (see call-out box). Based on evidence the CSB collected from the structural damage patterns in the mill buildings and from employee reports of corn dust and fire coming out of the gap mill air intake line just before the explosion(s), the CSB considers the Didion incident to be one or more dust explosions.