A BNSF Railway official says that a cargo train has derailed on a main rail line running across the Northwest.

BNSF spokesman Gus Melonas says that there are no injuries and no environmental threat from Thursday morning's derailment near Saco in northeastern Montana.

The rail line is closed as equipment and dozens of workers head to the site of the wreck.

Train traffic has been held and rail officials are looking into the possibility of rerouting other trains.

The train was headed from Minneapolis to Spokane, Wash. Seven empty cars derailed, with several toppling over an embankment.

Melonas says rail officials don't know what caused the derailment.