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New CSB Update on Didion Dust Explosion Investigation

May 4, 2018
Image courtesy of CSB
Image courtesy of CSB

The U.S. Chemical Safety Board (CSB) published an update on its investigation of last year’s fatal combustible dust explosion at Didion Milling in Cambria, WI based on information from 10 workers who were at the facility during the incident, according to an April 30 agency press release.

Five workers were killed and 12 others were injured during the May 31, 2017 event, including a 21-year-old employee who suffered a double leg amputation after being crushed by a railcar.

The agency said 10 of the 19 workers present at Didion Milling the night of the explosions described conditions at the facility in the lead up to the event:

  • Workers believed conditions at the mill on the night of the incident were ‘normal,’ and up until just moments before the explosions, workers either were unaware of any problems or assumed their troubleshooting efforts would reveal a typical and manageable situation.
  • Prior to the explosion workers reported seeing and smelling smoke coming from the facility.
  • Several workers entered various mill buildings to locate the source of smoke, but were unable to immediately find the cause.
  • Approximately 15 to 30 minutes before the explosions, workers focused their inspections on a piece of equipment called a gap mill. Workers then observed an air filter blow off the gap mill’s air intake line, resulting in corn dust filling the air and a three-to-four-foot flame shooting from the air intake line.
  • Around 11 p.m., one or more explosions occurred. The explosions caused a complete collapse of four of the nine buildings that make up the Didion facility; the remaining five were severely damaged.
  • Five workers died as a result of the explosions and the collapse of the buildings. The other 14 workers sustained injuries that ranged from minor to life-threatening.

A full technical analysis of the incident, along with an assessment of the firm’s dust management, is currently being prepared by the CSB.

The U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) proposed $1,837,861 in fines against Didion Milling last November, Powder & Bulk Solids reported. OSHA found that the explosion likely resulted from Didion’s failures to correct the leakage and accumulation of highly combustible grain dust throughout the facility and to properly maintain equipment to control ignition sources. OSHA cited Didion’s Cambria facility with 14 willful – including eight willful per-instance egregious– and five serious citations, most involving fire and explosion hazards.

The company filed an appeal against OSHA’s penalty in late 2017, saying in a statement that Didion did “not agree” with the agency’s findings.