Didion Milling Employees Found Guilty

Two Convictions, One Acquittal Reached in Didion Milling Explosion Cases

Todd Neeley
By  Todd Neeley , DTN Environmental Editor
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A federal jury in Wisconsin reached several verdicts in cases connected to a 2017 explosion at a Didion Milling corn mill that led to five employee deaths in Cambria, Wisconsin. (DTN file photo)

LINCOLN, Neb. (DTN) -- Two current and two former Didion Milling Inc. employees were found guilty of multiple charges in connection with a 2017 explosion at a Didion corn mill in Cambria, Wisconsin, that killed five workers and seriously injured others.

Didion Milling vice president of operations Derrick Clark was convicted on Oct. 13 by a federal jury in the U.S. District Court for the District of Western Wisconsin in Madison.

Clark was convicted of conspiring to falsify documents, making false Clean Air Act compliance certifications and obstructing the Occupational Safety and Health Administration's (OSHA) investigation of the explosion by making false and misleading statements during a deposition.

Former Didion Milling food safety superintendent Shawn Mesner was convicted on two charges. They include participating in a fraud conspiracy against Didion Milling's customers and conspiring to obstruct and mislead OSHA for his role in falsifying sanitation records of cleanings designed to remove accumulations of corn dust at the mill.

The jury also acquitted former Didion Milling environmental manager James Lenz of charges relating to falsifying environmental records and conspiring to make false statements and obstructing agency proceedings.

The court has yet to decide on a date for sentencing.

A fraud conspiracy conviction could lead to 20 years in prison, $1 million in fines and a requirement to forfeit assets derived from fraud.

Convictions for conspiracy to commit federal offenses and other offenses range from five to 20 years in prison and up to $1 million in fines.

Didion Milling Inc. declined to comment when contacted by DTN on Wednesday.

In a statement to DTN in May 2022, the company said it continued to believe crimes were not committed leading up to the explosion.

"Our thoughts and prayers remain strong for the families, friends, and coworkers of those affected by the accident," the company said.

"The tragic accident deeply affected everyone at Didion. We are disappointed the government has decided to pursue these unwarranted charges. What happened on May 31, five years ago, was a horrible accident, not a criminal act. While we have cooperated fully with the investigation since day one, we now must respond with a strong, vigorous defense for the company and our team. As a family-owned business for 50 years, we have a culture of safety and quality engrained in all we do. We take care of one another in the Didion family and we continue to invest in safety and quality because it is the right thing to do."


Didion Milling previously pleaded guilty to falsifying the cleaning logs and baghouse logs at the mill and agreed to pay a $1 million criminal fine and restitution of $10.3 million to the victims of the 2017 explosion.

Didion Milling shift superintendents Nicholas Booker, Michael Bright and Joel Niemeyer previously pleaded guilty to false statement charges for participating in falsifying cleaning and baghouse logs.

Didion Milling shift superintendent Anthony Hess pleaded guilty to obstructing OSHA by making false and misleading statements about the accuracy of the cleaning log during a sworn statement taken as part of OSHA's investigation into the mill explosion, according to an EPA news release.

Former Didion Milling environmental manager Joseph Winch previously pleaded guilty to conspiracy to conceal environmental violations from regulators by falsifying compliance certifications and providing falsified logs to regulators.

OSHA regional administrator Bill Donovan in Chicago said the convictions were important for protecting workers.

"Derrick Clark and Shawn Messner chose to intentionally mislead OSHA investigators and made false statements about their knowledge of working conditions at the plant to protect themselves and cover their mistakes," Donovan said in a news release.

"Their blatant actions demonstrated a callous disregard for the loss of life, injuries and property damage that occurred under their leadership at the Didion mill. Both Clark and Messner ignored their legal and moral obligation to protect workers before and after the explosion."

Because grain dust can be explosive, OSHA said safety standards require grain milling facilities to develop and implement housekeeping programs, including regular cleanings to reduce grain dust accumulation.

Didion Milling maintained its master sanitation schedule to record the performance of required cleanings. Clark and Mesner were convicted of participating in a conspiracy to falsify that cleaning log, according to EPA, including directing others to backfill entries for uncompleted cleanings.

Read more on DTN:

"Didion, Employees Indicted in Explosion," https://www.dtnpf.com/…

Todd Neeley can be reached at todd.neeley@dtn.com

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Todd Neeley

Todd Neeley
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