The owners of a Cambria corn mill that exploded in 2017, killing five workers, have agreed to plead guilty to two federal criminal charges and pay a $1 million fine and $10.25 million in restitution to the estates of the deceased workers, according to a plea agreement filed late Wednesday in federal court in Madison.
Didion Milling Inc., along with six of its managers and superintendents, was charged in May 2022 in a nine-count criminal indictment for its alleged role in failing to ensure that work was done to safely handle highly combustible corn dust and in keeping deliberately false records before the May 31, 2017, explosion at the company’s Cambria corn mill.
According to the agreement for Sun Prairie-based Didion, signed by company CEO Riley Didion, the company agreed with prosecutors to plead guilty to two counts of making false entries in logbooks that were required by the Environmental Protection Agency and the Occupational Safety and Health Administration. The records are key to maintaining safe dust levels in the plant, which were provided to investigators after the explosion.
In addition to the $1 million fine and $10.25 million in restitution, the company agreed to serve five years of “organizational probation.” The agreement states that while on probation it will allow OSHA to inspect the Cambria mill without a warrant or advance notice and without undue delay or any specified reason. The inspections, however, would occur no more than twice a year.
The indictment alleged that the company falsified logbooks used by inspectors to determine whether the plant was handling dust from corn milling in a safe manner and whether the company was complying with rules about cleaning dust, and that there was a conspiracy to falsify the logs.
At the Cambria plant, Didion mills corn into flour and similar products that other customers buy for use in their products.
Duelle Block, Robert Goodenow, Charly Nunez, Angel Reyes-Sanchez and Pawel Tordoff were killed in the blast or died soon after.
The U.S. Chemical Safety and Hazard Investigation Board is expected to release its final report on the Cambria explosion sometime in the second half of this year. In general, grain dust, when concentrated in the air, can be ignited by a spark.
The indictment states the explosion originated in milling equipment in one of the plant’s mills and spread quickly because of combustible dust accumulations.
Trial Ahead
A trial is scheduled to begin Monday before U.S. District Judge James Peterson for the remaining co-defendants, which include Derrick Clark, who was vice president for operations at Didion; Shawn Mesner, who was food safety superintendent; and James Lenz, who was environmental manager.
According to court records, guilty pleas to some of the charges have already been entered for Anthony Hess, who was a day shift superintendent at Didion; Joseph Winch, who was environmental coordinator at Didion; and Joel Niemeyer, who was also a day shift superintendent at Didion.
Niemeyer pleaded guilty on Tuesday to conspiracy to conceal environmental and safety violations from auditors and government agencies, and Winch pleaded guilty to the same charge on June 15. Hess pleaded guilty on Sept. 19 to obstruction. All of those charges carry up to five years in prison.
Sentencing dates for the three have not been set, and no date has been set for Didion to formally enter its guilty pleas as stated in the agreement.
In a statement Thursday, Riley Didion said the company was thankful to have reached the plea deal and was pleased most of the financial settlement will go to the workers’ estates, calling the explosion “heartbreaking.”
“What happened in Cambria in May of 2017 was tragic, and we continue to offer prayers for those who were affected,” he said. “With this agreement in place, we can devote our full attention to serving our team, community, farmers, and customers with the highest standards of safety and quality.”
The case is being prosecuted in Madison by the U.S. Department of Justice’s Environment and Natural Resources Division.
False Entries
According to a statement of facts to which Didion agreed, filed with the plea agreement, dust from corn milling is regulated under the federal Clean Air Act, under permits issued by the state Department of Natural Resources.
Those permits require Didion to operate filters, called baghouses, where dusty air is cleaned by filters and released into the environment. They are monitored by “pressure drops,” which can indicate whether there are malfunctions in baghouses. A high pressure reading, for example, can indicate that the system is clogged.
Didion’s permit required it to monitor and record pressure drops at each of about 14 baghouses every eight hours and enter those readings on an electronic spreadsheet. That log is used by inspectors to determine whether Didion is in compliance with its air quality permits. Monitoring reports also have to be submitted to DNR every six months.
From 2015 to May 2017, according to the statement of facts, Didion shift workers and superintendents made false entries on baghouse logs, including filling in pressure drops that appeared to comply with rules when the actual numbers were outside the allowed range. Emails also showed Didion employees discussed backfilling entries for pressure drop readings in baghouse logs.
On May 17, 2017, during a DNR inspection, Didion’s environmental manager showed logs to inspectors knowing they contained false entries. Logs containing false entries for 2015, 2016 and 2017 were also knowingly sent to DNR in August 2017, according to the statement of facts.
Combustible dust also must be cleaned up to reduce the possibility of an explosion. Didion set a master sanitation schedule for cleanings, and shift superintendents were to make sure the cleanings were done and then enter the work in a logbook.
On May 19, 2017, the statement says, Didion employees falsely indicated in the logbook that required dust cleanings had been performed during the week of May 1-7, 2017, when they had not. The 2017 logbook was given to OSHA in August 2017 during its investigation of the Cambria mill explosion.
Ed Treleven | Wisconsin State Journal
The Associated Press contributed to this report.