U.S. Chemical Safety Board releases Didion Milling combustible dust video
The U.S. Chemical Safety and Hazard Investigation Board (CSB) has released a new safety video examining the fatal combustible dust explosions and fires at the Didion Milling facility in Cambria, Wisconsin.
The incident occurred on May 31, 2017, killing five employees and injuring 14 others. The explosions and subsequent fires destroyed the facility and caused more than $15 million in property damage. According to the CSB, the event was triggered by the ignition of combustible corn dust generated during dry corn milling operations.
The video, titled Deadly Dust: Explosions at Didion Milling, includes an animated reconstruction of the events leading up to the incident, along with commentary from Board Member Sylvia Johnson and investigators Melinda Hartz and Cruz Redman. It shows how a smoldering accumulation of dust inside the grinding process ignited shortly after 10:30 p.m., causing an initial explosion within milling equipment. Fires and secondary explosions then spread throughout the mill buildings.
The CSB released its final investigation report in December 2023. The new video highlights five of the 13 safety issues identified in the report, including failures in process hazard recognition, dust hazard analysis, fugitive dust management, process safety leadership, and regulatory coverage of combustible dust hazards.
The video also reinforces safety recommendations issued to Didion Milling, the National Fire Protection Association, and the federal Occupational Safety and Health Administration (OSHA). Among those recommendations is the CSB’s long-standing call for OSHA to develop a comprehensive combustible dust standard for general industry, a measure the agency has urged since 2006.
According to Board Member Sylvia Johnson, the lack of an overarching combustible dust standard continues to leave workers at risk. She stated that robust regulation is essential to prevent deadly incidents like the Didion Milling explosion from recurring.
The CSB is an independent federal agency responsible for investigating chemical incidents and hazards that may result in catastrophic releases of hazardous substances. While the Board does not issue citations or fines, it develops safety recommendations for industry, labor groups, and regulatory agencies, including OSHA and the Environmental Protection Agency.