I-90 westbound at mile marker 350 east of Mitchell was closed for several hours last night after bales on a semi-trailer caught on fire. Fire crews were dispatched to the scene just before 7 PM. The semi was traveling on Highway 25 and proceeded onto I-90 westbound at the Emery exit. The cause of the fire is not known at this time. No one was injured in the fire. Traffic was rerouted, and the interstate was reopened just after 10 PM.