South Dakota Department of Public Safety spokesman Tony Mangan says the crash happened Wednesday morning in Mitchell. Investigators say the cargo vehicle crossed into the path of the semi, which had the right of way.
Mangan says the National Guard members and semi driver were taken to a hospital with serious non-life-threatening injuries.
The soldiers from the 1244th Transportation Company based in North Riverside, Illinois, had been training in the Black Hills. The semi driver was hauling liquid carbon dioxide from the Poet Research Center in Scotland, South Dakota. No liquid was spilled.
The driver of the military vehicle is facing charges.