(32bf) Process Safety Hazard Analysis: Didion Milling Inc. Combustible Dust Explosion

On Wednesday May 31, 2017, around 11:00 pm in Cambria, Wisconsin at the Didion Milling Inc. dry corn milling facility, a series of combustible dust explosions occurred due to an improper temporary connection in the process. This connection was made to increase production of bran, one of the materials processed at the facility. It was determined that a fire started from smoldering particles within the system and due to the highly interconnected nature of the process systems, the fire propagated throughout the facility. A total of 19 employees were onsite at the time of the incident. None of the employees were able to evacuate in time resulting in five deaths and 14 injuries. The collapse and damage to the facility buildings caused an estimated $15.4 million in property damage. No off-site damage was reported. Numerous safety issues were identified by the CSB including inadequate process hazard recognition, lack of engineering controls, a poor emergency response plan, and more. All of these issues had a major contribution to the severity of the incident. The CSB also gave 13 total recommendations to Didion, OSHA, and the NFPA that acted to prevent future incidents that may involve the aforementioned safety hazards. These recommendations included the formation of a new comprehensive combustible dust standard by OSHA, as well as requiring Didion to update many of their systems including emergency response plans and process hazard analysis, and for the NFPA to update NFPA 61 or other successor standards.