CSB Says Didion Milling Has Not Implemented Safety Fixes After Fatal 2017 Explosions
The U.S. Chemical Safety and Hazard Investigation Board (CSB) announced Aug. 11 that Didion Milling, Inc. has failed to implement nine safety recommendations stemming from the agency’s investigation of fatal explosions at the company’s Cambria, Wisconsin, facility in May 2017. The incident killed five employees and seriously injured 14 others. The CSB said the unaddressed recommendations target deficiencies in the company’s safety management system and failure to adopt relevant industry safety standards.
The CSB issued the recommendations in its Dec. 6, 2023, final report on the explosions. According to the agency, Didion has not provided any substantive response or documentation showing progress, despite multiple letters, phone calls and emails over the past 20 months. Didion’s attorneys have argued that a separate Occupational Safety and Health Administration settlement — involving $1.8 million in civil penalties for willful and serious violations — addressed the same issues. The CSB maintains that its recommendations go beyond OSHA regulatory requirements.
On Dec. 10, 2023, Didion provided Chemical Processing with a media statement in response to the CSB’s findings. The company said it was “pleased” the agency agreed the 2017 explosion did not start from fugitive dust related to housekeeping but from ignition of corn dust inside process equipment. Didion said it disagrees with much of the CSB’s report, claiming it contains “many factual errors” and omits data provided by the company and combustible dust safety experts.
Didion said the majority of the CSB’s recommendations were implemented when it built a new mill in 2018 with guidance from engineering and safety experts “to exceed industry safety and quality standards.” The company added it continually evaluates safety procedures and equipment to align with or exceed best practices. “Didion continues to hold those lost and injured in the accident in our hearts,” the statement said.
On Aug. 5, 2025, the CSB sent a final letter urging Didion to take action or risk the case being closed with an "Unacceptable Response" designation.
In a separate development, the U.S. Department of Justice announced in February 2024 that three former Didion executives, including the vice president of operations, were each sentenced to two years in prison and fined for falsifying safety records and obstructing investigations. The company was fined more than $10 million and placed on five years’ probation after being convicted of falsifying environmental and sanitation logs.
