United States v. Didion Milling, Inc., et al.

             On September 29, 2023, Didion Milling, Inc., pleaded guilty to charges related to a catastrophic explosion at its Cambria, Wisconsin, corn mill facility. Five Didion Milling employees were killed in that explosion and others were injured. The company pleaded guilty to falsifying records related to its Occupational Safety and Health Act and Clean Air Act obligations to conceal violations from government agencies (18 U.S.C. § 1001(a)(3)).

          Didion Milling was required to operate “baghouses,” equipment designed to prevent particulate matter, such as corn dust, from being released into the environment from the corn mill. From at least 2015 to May 2017, Didion Milling employees, including shift workers and shift superintendents, made false entries in the mill’s “baghouse logs,” disguising data meant to monitor and document whether the mill’s baghouse equipment was working properly to filter particulates from the air. Didion Milling’s environmental manager provided baghouse logs for 2015, 2016 and 2017 to environmental inspectors, knowing that they contained false entries.

            The company was also required under Occupational Safety and Health Act safety standards to develop and implement a housekeeping program to reduce the accumulation of fugitive grain dust within its corn mill. Didion Milling maintained a “master sanitation schedule” logbook listing each of the required dust cleanings and the specific dates by which the cleanings were supposed to be completed. The sanitation logbook contained spaces for Didion Milling employees to record that the dust cleanings had been performed and that documentations procedures had been followed. On May 19, 2017, Didion Milling employees falsely initialed, signed and dated entries in the sanitation logbook for the week of May 1 through May 7, 2017, giving the appearance that the required dust cleanings were performed when they had not been. Didion Milling provided the sanitation logbook containing the false May 2017 dust cleaning entries to the Occupational Safety and Health Administration (OSHA) during its investigation of the May 31, 2017 explosion at the Didion Milling corn mill.

            The U.S. Environmental Protection Agency Criminal Investigation Division and the Wisconsin Department of Natural Resources conducted the investigation.