A semitrailer truck veered off the main highway through Rochester and rammed into a commercial building, killing the driver in a fiery crash, authorities said.

The semi left southbound Hwy. 52 shortly before 4 p.m. on Monday, went down a grassy hill and smashed in the ServiceMaster building on 7th Street NW., according to the State Patrol.

Benjamin D. Heim, 25, of St. Charles, Minn., was killed, the patrol said. Two women, ServiceMaster employees, were injured but are expected to survive. Fire crews tended to the flames and hot spots for several hours after the crash.

Authorities have yet to say why the semi went off the road.