The explosion May 31, 2017, leveled most of the sprawling facility about 45 miles (72 kilometers) northeast of Madison. Killed in the blast were Didion employees Duelle Block, Robert Goodenow, Carlos “Charly” Nunez, Angel Reyes and Pawel Tordoff. Fifteen more people were injured.
Federal inspectors have said an accumulation of grain dust likely caused the explosion. Corn dust is combustible; if concentrations in the air reach a high level a spark or other ignition source can cause it to catch fire and explode. Federal regulations require grain mill operators to perform regular cleanings to reduce dust accumulations that could fuel a blast.
The U.S. Occupational Safety and Health Administration fined Didion more than $1.8 million in connection with the explosion in the months following the explosion.