MADISON, WISCONSIN, US — Current and former Didion Milling Inc. officials were convicted by a US federal jury on Oct. 13 of workplace safety, environmental, fraud and obstruction of justice charges related to a 2017 explosion that killed five workers and seriously injured others.

Derrick Clark, vice president of operations at Didion Milling, was convicted of conspiring to falsify documents, making false Clean Air Act compliance certifications as Didion’s “responsible official” and obstructing the Occupational Safety and Health Administration’s (OSHA) investigation by making false and misleading statements during a deposition, according to the Department of Justice (DOJ).

Shawn Mesner, former food safety superintendent at Didion Milling, was convicted of participating in a fraud conspiracy against Didion Milling’s customers and conspiring to obstruct and mislead OSHA for his role in falsifying sanitation records that track cleanings to remove corn dust from the mill.

Didion Milling environmental manager James Lenz was acquitted of charges relating to falsifying environmental records and conspiring to make false statements and obstruct agency proceedings.

“The trial and convictions in this case show that compliance matters, and attempting to hide non-compliance, is not just a ‘technical’ violation,’” said Assistant Attorney General Todd Kim of the Justice Department’s Environment and Natural Resources Division (ENRD). “Managers and officers who enable corporate cultures that tolerate, encourage or cover up violations, and who participate in falsifying documents and obstructing agency investigations, will and must be held accountable in addition to the corporations.”

Sentencing hearings will be scheduled for a later date.

According to the DOJ, Didion Milling used a master sanitation schedule to record required cleanings. Clark and Mesner were convicted of falsifying the cleaning log, and telling others to backfill entries for cleaning that was not completed.

OSHA has six months to investigate and issue citations after a safety violation. In situations where workers die, corporate managers who knew about violations can receive a “willful” citation and criminal referral.

In reviewing Clark’s testimony from September 2017, OSHA found that he gave false and misleading statements about his knowledge of problems with the dust collection system, explosion hazards and prior fires at the facility, the DOJ said.

As part of its permit under the Clean Air Act, Didion Milling was required to have baghouse equipment, which helps limit the release of particulate matter. A senior manager was required to periodically certify that the mill was in compliance with the permit and disclose any violations.

The DOJ said Clark was found to have falsely certified compliance without disclosing that baghouse logs had been systematically falsified to conceal permit violations.

The DOJ also said Mesner conspired to deceive Didion’s customers about its sanitation practices by repeatedly showing them a falsified cleaning log. He also told operations personnel to falsify the log so it appeared as if the cleaning schedule was followed, the DOJ noted.

Didion Milling previously pleaded guilty to falsifying the cleaning logs and baghouse logs at the mill and agreed to pay a criminal fine of $1 million and restitution of $10.25 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 the falsification of the cleaning logs 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.

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.