Sixteen rail cars caught fire and six exploded after a freight train derailed in an unpopulated area of eastern Montana, sending at least one fiery mushroom cloud into the sky, railroad officials said Monday.

Fifteen tanker cars containing the fuel additive denatured alcohol and one car hauling cardboard derailed Sunday between Baker and Ismay, about 180 miles northeast of Billings.

No one was hurt in the crash that sent flames 70 feet into the air as rail cars burned through the night, said Burlington Northern Santa Fe spokesman Gus Melonas.

"It was a chain reaction of one car catching fire and another car catching fire as well," Melonas said.

Firefighter Kelly Gray, of Plevna, took a picture of the flames as one of the cars exploded.

"We were just waiting for the cars to blow up and got a good mushroom percussion," Gray told The Billings Gazette (http://bit.ly/OKQjhG). "The heat felt like your eyebrows were going to singe."

The derailed cars were part of a 106-car train headed to Laurel from Aberdeen, S.D. It was traveling about 23 mph at the time of the derailment, Melonas said.

Crews intend to remove the damaged cars and replace about 1,100 feet of track and ties. The line, used by eight to 10 trains a day, could reopen as soon as Wednesday. Some trains were being re-routed.

The cause of the derailment was under investigation.