GREENSBURG, Pennsylvania — Five people were killed and about 60 were injured on the Pennsylvania Turnpike early Sunday morning, when a loaded bus went out of control on a hill and rolled over, setting off a chain reaction that involved three tractor-trailers and a passenger car.

The injured victims, ranging from 7 to 67 years old, are all expected to survive, though two patients remain in critical condition, authorities and hospital officials said Sunday afternoon.