In one of the biggest workplace disasters this year, three workers were killed in a massive explosion at the Didion Milling Plant in Cambria, Wisconsin, last week. The blast leveled most of the plant. Nearly a dozen workers were taken to hospitals following the explosion and fire.

While the investigation will go on for a while, signs point to a grain dust explosion. The plant processes corn for ethanol and other uses and  had been cited by OSHA for grain dust hazards in 2011:

U.S. Occupational Health and Safety Administration (OSHA) records show the plant was cited in 2011 for not taking precautions against dust explosions. They can occur when high concentrations of dust particles are suspended in the air in a confined space during grain handling. A spark from something like a cigarette butt ignites it, according to the U.S. Department of Agriculture.

There were five grain dust explosions in the U.S. last year, including two that were fatal, according to a Purdue University annual report. Keeping facilities clean of dust and equipment in good working order to reduce the possibility of igniting the dust are key to preventing explosions, the report said.

The federal safety agency ordered the mill to correct the problem by April 2011, and the records show Didion paid a $3,465 fine and the case was closed in September 2013. Clark and James Brunker, a senior executive with M3 Insurance, which insures the company, said the problem was corrected.

The plant also received a citation for electrical hazards in 2014.

There were five grain dust explosions in 2016, including two that were fatal, according to a Purdue University annual report. That’s compared to eight in 2015 and a 10-year average of 9.2 per year.

Dust explosions can occur when high concentrations of dust particles are suspended in the air in a confined space during grain handling and a spark from a piece of machinery can ignite it. OSHA has a grain handling standard that covers a number of hazards, including grain dust. OSHA warns that

Grain dust explosions are often severe, involving loss of life and substantial property damage. Over the last 35 years, there have been over 500 explosions in grain handling facilities across the United States, which have killed more than 180 people and injured more than 675. Grain dust is the main source of fuel for explosions in grain handling. Grain dust is highly combustible and can burn or explode if enough becomes airborne or accumulates on a surface and finds an ignition source (such as hot bearing, overheated motor, misaligned conveyor belt, welding, cutting, and brazing). OSHA standards require that both grain dust and ignition sources must be controlled in grain elevators to prevent these often deadly explosions.

Since the grain handling standard was issued in 1987, “explosions were reduced by 42 %, the number of injured was reduced by 60 % and the number killed was down by 70%.”

Workplace safety advocates called for stronger OSHA enforcement:

“Our prayers are with the victims and families of this terrible event,” said Jim Schultz, executive director of the Wisconsin Committee on Occupational Safety and Health (WisCOSH). “Duelle Block, Robert Goodenow and Pawel Tordoff lost their lives working in a grain mill, where explosions caused by dust are a known and preventable hazard.”

“From long and sad experience, we know that most of the events in which workers become sick, are injured, or lose their lives are preventable,” said Marcy Goldstein Gelb, executive director of the National Council for Occupational Safety and Health (National COSH).  “All employers must take pro-active steps to reduce workplace risks – but we can’t rely on voluntary action.  OSHA needs resources to inspect workplaces issue fines and penalties, which have an important deterrent effect.”



Correction: The original version of this post mistakenly linked to another 2011 citation against Didion for combustible dust hazards under OSHA’s General Duty Clause. It has since been corrected to cite the grain handling standard violations.

2 thoughts on “Three Workers Killed in Corn Mill Explosion”
  1. Were the 2011 violations cited by OSHA not cited under the general duty clause?
    I’d be interested in some discussion of how the grain standards you reference cover dust, and if a broader combustible dust standard would be of help in preventing incidents like this one.

    1. Was just discussing that with some people Ken. The original citation that I originally (and mistakenly) cited was a General Duty Clause combustible dust citation that same year. I have since corrected it to reference the Grain Handling citation.

      We’re not sure what the general duty clause citation was for. It’s possible that those violations occurred in the methanol production part of the facility and not in the grain handling part. There is not OSHA combustible dust standard for anything outside of grain handling.

      It’s too early to tell right now whether this incident fell under the grain handling standard, or whether it will be covered by General Duty.

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