Department of Labor Logo OSHA News Release - Region 5


December 14, 2023

Didion Milling Inc., agrees to pay $1.8M in penalties, make comprehensive safety improvements after 2017 Cambria corn mill explosion killed 5 workers

Company settles OSHA investigation, as 7 company officials await sentencing

CAMBRIA, WI – The U.S. Department of Labor has reached a settlement agreement with Didion Milling Inc. that requires the Cambria corn milling company to pay more than $1.8 million in penalties after a May 31, 2017, explosion that killed five workers and injured more than a dozen others. The company has also agreed to make extensive safety and health improvements at the facility.

The parties filed their Joint Notification of Full Settlement with the Occupational Safety and Health Review Commission entered the agreement as a final order on Dec. 13, 2023. An independent federal agency, OSHRC decides contested citations or penalties the department's Occupational Safety and Health Administration issues to employers after workplace inspections.

"Didion Milling's agreement to make extensive safety improvements and work with OSHA and industry experts to protect the mill's workers will protect the safety and lives of their current and future employees," said OSHA Regional Administrator Bill Donovan in Chicago. "OSHA will hold Didion leadership accountable for changing the corporate culture to focus on safety and health by working with experts, and with management and workers. Together, they can develop and continually test safety measures and emergency response procedures and train employees in hazard recognition. The five workers who lost their lives and those injured in this preventable tragedy must never be forgotten."

Didion Milling has agreed to make extensive safety improvements including the following:

  • Develop a corporate-wide safety and health management system within six months with input from management and workers and create a safety committee.
  • Meet with OSHA at least yearly to discuss safety and health issues.
  • Work with third-party experts to ensure mechanical integrity of key pieces of equipment.
  • Conduct hazards analyses on grain dust and the need for flame-resistant personal protective garments.
  • Provide time, equipment, staffing and training related to combustible dust housekeeping and mechanical integrity equipment inspections, tests and preventative maintenance.
  • Develop a management of change program and procedure overseen by a qualified person knowledgeable in the fire and deflagration hazards of agricultural or food dust.
  • Review changes to grain processing equipment including mills, dryers, dust collector filters and bucket elevators for safety compliance.
  • Create an incident-reporting and investigation system to identify incidents such as severe near misses, severe injuries, combustible dust fire, deflagration and explosion events, and material releases.
  • Conduct emergency planning and response training with the local fire department annually, if practical.
  • Train employees on the updated safety and health management system within 30 days of implementation.
  • Conduct training in languages understood by employees.

The settlement follows the Oct. 13. 2023, convictions of company Vice President of Operations Derrick Clark and its former Food Safety Superintendent Shawn Mesner by a federal jury in Madison, Wisconsin, for falsifying documents and obstructing an OSHA investigation.

Didion Milling Inc. pleaded guilty on Sept. 29, 2023, to charges related to falsifying the mill's cleaning and baghouse logs and agreed to pay restitution of more than $10 million to the 2017 explosion's victims and a $1 million criminal fine.

In addition, other company officials have pleaded guilty and await sentencing before U.S. District Court Judge James D. Peterson for the Western District of Wisconsin on various charges related to the incident. These include guilty pleas by shift superintendents Nicholas Booker, Michael Bright and Joel Niemeyer for making false statements; by shift superintendent Anthony Hess for obstructing OSHA's investigation; and by former environmental manager Joseph Winch for conspiring to conceal violations from regulators by falsifying compliance certifications and providing falsified logs.

Operating and based in Sun Prairie, Didion Milling Inc. since 1972, the company operates a corn milling and biofuels facility in Cambria and production facilities in Markesan and Johnson Creek.

Learn more about OSHA.

Occupational Safety and Health Review Commission 
Docket No. 17-2156

U.S. vs. Didion Milling Inc, et. al 
Case No. 22-CR-055-JDP

Media Contacts:

Scott Allen, 312-353-4727, allen.scott@dol.gov 
Rhonda Burke, 312-353-4807, burke.rhonda@dol.gov 

Release Number: 23-2319-NAT