Didion Milling Officials Sent to Prison for Faking Safety Records Before Fatal Dust Explosion
MADISON — The corn dust that leveled Didion Milling’s Wisconsin mill was supposed to have been cleaned up — the logs said so. The logs were fake. On February 16, 2024, former vice president of operations Derrick Clark and former food safety superintendent Shawn Mesner were each sentenced to 24 months in federal prison for their roles in covering up the conditions that killed five workers.
The Incident
On May 31, 2017, accumulated grain dust inside the corn mill in Cambria, Wisconsin ignited and exploded, destroying much of the facility. Five workers were killed and about a dozen more were injured. Grain dust is violently explosive when suspended in air — which is exactly why OSHA’s grain handling standard demands housekeeping programs and maintained equipment to control dust and ignition sources.
The Investigation
In November 2017, OSHA cited Didion Milling with 14 willful and 5 serious violations and proposed $1,837,861 in penalties, finding the explosion likely resulted from failures to correct leaking, accumulating grain dust and to maintain the equipment that controlled ignition sources.
Then the criminal case landed. Federal prosecutors proved that Didion personnel had systematically falsified the mill’s cleaning logs and baghouse records — paperwork that made a dust-choked mill look compliant. In September 2023, the company pleaded guilty and agreed to a $1 million criminal fine plus $10.25 million in restitution to victims. A jury convicted Clark of making false compliance certifications, obstructing OSHA’s investigation and lying under oath, and Mesner of conspiring to commit fraud and mislead OSHA with falsified sanitation records. In a parallel civil settlement, Didion agreed to pay the full OSHA penalty and implement a corporate-wide safety management system, dust hazard analyses, and near-miss reporting.
OSHA’s Stance
“The five workers who lost their lives and those injured in this preventable tragedy must never be forgotten,” said OSHA Regional Administrator Bill Donovan. Back in 2017, then-Regional Administrator Ken Nishiyama Atha put the cause plainly: “Didion Milling could have prevented this tragedy if it had addressed hazards that are well-known in this industry.”
Lessons to Take Home
Combustible dust does not negotiate — as we also reported in the fatal Horizon Biofuels explosion, accumulated dust turns a spark into a bomb. In a grain facility, housekeeping is not janitorial work, it is explosion prevention, and it only works when it actually happens.
The deeper lesson is about paperwork culture. A safety log that gets pencil-whipped is worse than no log at all: it hides the hazard from everyone downstream, including the workers walking over it. Didion shows where that road ends — five funerals, eight-figure restitution, and managers in federal prison, because falsifying records converts a safety failure into a crime. If your inspection sheets are being signed without the work being done, that is a shortcut your whole team needs to talk about this week.
