News Release

Grand jury indicts Didion Milling Inc., six managers on nine counts related to five deaths, numerous serious injuries in 2017 Cambria corn mill explosion

Company, managers attempted to obstruct, mislead OSHA investigation

CAMBRIA, WI – A federal grand jury has indicted the operator and six management officials of a Cambria corn mill – where a May 31, 2017, explosion killed five workers and injured 15 others – on nine criminal counts, including two counts related to willful violations of federal workplace safety standards for grain handling.

Handed down by a grand jury in the U.S. District Court for the Western District of Wisconsin in Madison on May 11, 2022, the indictment of Didion Milling Inc. and its current and former managers includes counts of document falsification in contemplation of a U.S. Department of Labor, Occupational Safety and Health Administration investigation and obstructing the federal OSHA investigation. The indictment also charges the company and the six officials falsified entries in a cleaning logbook, which involved matters under the jurisdiction of OSHA.

The indictment alleges that Didion Milling willfully violated two federal safety standards in the Occupational Safety and Health Act -- by failing to develop and implement a written program to effectively prevent and remove combustible grain dust accumulations, and by not installing venting or suppression on a dust filter collector to prevent an explosion – thereby, causing the deaths of five employees due to the combustible dust explosion on May 31, 2017.

The grand jury indictment also includes the following allegations:

  • Didion Milling and four employees – vice president of operations, Derrick Clark; former food safety superintendent, Shawn Mesner; former shift superintendent, Anthony Hess; and former shift superintendent, Joel Niemeyer – conspired to commit fraud by agreeing to take deceptive measures to conceal the failure to adhere to food safety procedures at the mill.
  • Didion Milling, Clark, Mesner, Hess and Niemeyer – along with former environmental coordinators, James Lenz and Joseph Winch – conspired to commit federal offenses to conceal violations and unsafe conditions from auditors and government agencies.
  • Hess, Clark and Didion obstructed justice by providing false and misleading testimony after the explosion to OSHA about their knowledge of combustible dust hazards at the mill.

Former Didion Milling shift superintendents Michael Bright and Nicholas Booker pleaded guilty previously to making false entries in Didion Milling’s cleaning logbook and false entries in the baghouse log, which involved matters within the  jurisdiction of OSHA and EPA, respectively.

Based in Sun Prairie, Didion Milling Inc. has been in operation since 1972. The company operates a corn milling and biofuels facility in Cambria and production facilities in Markesan and Johnson Creek.

An indictment is merely an allegation and all defendants are presumed innocent until proven guilty beyond a reasonable doubt in a court of law.

Learn more about OSHA.

U.S. vs. Didion Milling Inc, et. al

Case No. 22-CR-055-JDP


Occupational Safety & Health Administration
May 16, 2022
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Media Contact: Scott Allen
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Media Contact: Rhonda Burke
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