BILLINGS, Mont. (AP) — The dangers posed by a spike in oil shipments by rail extend beyond crude from the booming Bakken region of the Northern Plains and include oil produced elsewhere in the U.S. and Canada, U.S. safety officials and lawmakers said.

Acting National Transportation Safety Board Chairman Christopher Hart said all crude shipments are flammable and can damage the environment — not just the Bakken shipments involved in a series of fiery accidents.