A Wisconsin federal judge has sentenced six Didion Milling Inc. officials for their role in a fatal explosion at a facility operated by the corn milling company in 2017.
“These defendants put Didion workers in grave danger, and five people tragically lost their lives, devastating their families and their community,” said U.S. Attorney General Merrick B. Garland. “Companies of all sizes should take note: Failure to comply with our country’s workplace safety and environmental laws can cost workers their lives and put individual corporate managers in federal prison.”
On May 31, 2017, at around 10:30 p.m., a fire originated in milling equipment at Didion’s corn mill in Cambria, Wis. The fire led to a series of combustible dust explosions in the facility, killing five workers and seriously injuring others. The explosions also damaged and caused the collapse of multiple mill buildings. An investigation into Didion’s worker and food safety and environmental practices uncovered criminal violations of law attributable to both the company and senior officials.
Grain milling generates grain dust, which must be effectively managed for workplace safety, environmental, and food safety and quality reasons. Mill operators must adhere to rules and requirements intended to minimize hazards. Grain dust is combustible, and mill operators need to maintain workplace safety through cleaning programs that remove dust accumulations from inside a mill. Mill operators must also capture dust before it is emitted into the environment as particulate matter, a kind of air pollutant.
Investigations of the explosion at Didion’s Cambria mill uncovered long-standing inadequate safety measures and improper handling of grain dust that Didion and its employees concealed through falsified documents and other obstructive conduct.
Crimes and sentences
Didion Vice President of Operations Derrick Clark was sentenced to two years in prison, a year of supervised release, and a $5,000 fine. Clark was convicted in October 2023 of conspiring to falsify documents relating to dust cleaning practices in the mill and the operation of air pollution prevention equipment, and making false compliance certifications as Didion’s “responsible official” under the Clean Air Act. He was also convicted for obstructing the Occupational Safety and Health Administration’s (OSHA) investigation of the explosion at the corn mill by making false and misleading statements during a sworn deposition.
Former Environmental Manager Joseph Winch was sentenced to two years in prison, two years of supervised release, and a $10,000 fine for conspiring to falsify Didion’s environmental compliance certifications. Winch pleaded guilty to the conspiracy charge before trial, but the court’s sentencing took into consideration Winch’s effort to obstruct the trial of his co-defendants by committing perjury during his trial testimony.
Former Food Safety Superintendent Shawn Mesner was sentenced to two years in prison and a year of supervised release after being convicted in October 2023 of conspiring to commit fraud and to falsify Didion’s sanitation log. Falsification of the log was part of a scheme to mislead Didion’s customers and auditors about the company’s sanitation practices. The log also related to Didion’s compliance with worker safety protections, including the required cleanup of combustible dust, like fine grain dust, to prevent fires and explosions in grain handling facilities. The log purported to be a record of those dust cleanings. Mesner also provided untruthful testimony to OSHA during a sworn statement after the explosion.
The federal judge also sentenced three former Didion shift superintendents—Anthony Hess, Joel Niemeyer, and Michael Bright—who were convicted of crimes relating to falsification of Didion’s sanitation log. All three pleaded guilty to felonies before trial and accepted responsibility for their actions.
Hess was sentenced to a year of probation and a $5000 fine; Niemeyer was sentenced to a year of probation and a $1000 fine; and Bright was sentenced to a year of probation. A fourth shift superintendent who pleaded guilty to felonies, Nicholas Booker, is scheduled to be sentenced in March.
Didion, the company, pleaded guilty to falsifying its environmental and sanitation logs. The judge sentenced the company in January to pay $10.25 million in restitution to the victims of the explosion and a $1 million fine, as well as to serve five years of probation with special conditions related to oversight of Didion’s operations.
Acting U.S. Secretary of Labor Julie Su said, “The court’s sentences hold the company and these individuals accountable and send a clear message that cover-ups related to workplace safety will not be tolerated.”