A vehicle crashed through a chain-link fence and struck a building about 11:20 a.m. Saturday in East Dundee, authorities said.
The single-car crash occurred in the now-vacant Taylor Rental Building on Route 25, north of Route 72, East Dundee Assistant Fire Chief Anthony Pompa said.
An East Dundee police officer happened to be driving behind the man, who appeared to be in his early 40s and may have had a medical emergency, Pompa said.
The driver was taken to Sherman Hospital in Elgin with serious injuries, Pompa said. No additional information was available about the driver or what may have caused the crash.
The crash did not cause any structural damage to the building, Pompa added.