The Minneapolis Fire Department responded to a fire in a University warehouse next to the train tracks behind Sanford Hall at approximately 10:30 p.m. Wednesday.

A pile of woodchips caught fire in the warehouse, which stores both woodchips and coal that heat the University, said Capt. Dennis Mack of the Minneapolis Fire Department.

It was unclear as of press time how the fire started, though fire and police officials said they believe it was spontaneous combustion.

The coal had been in the warehouse all summer and was not supposed to be used until October, said Foster Wheeler, a boiler operator at the warehouse.

University mechanic Jeff Kramer said a shipment of woodchips had arrived earlier in the day.

University students who saw the fire called 911.

No one was injured. Ambulance crews and police were also on the scene.

Approximately 25 passers-by stood outside watching firefighters put out the fire. It was reduced to small flames and smoke by midnight.

John Olson, a junior who lives near Fourth Street and 11th Avenue, said he smelled the smoke from his house.

He and his roommate junior Laura Porter walked from their house to the University Avenue location to watch the fire.

“There was a lot of smoke, but no flames,” Porter said.

– David McCoy contributed to this report.