BILLINGS, Mont. -

U.S. officials say the danger posed by a dramatic increase in North American oil train traffic extends far beyond shipments from the booming Bakken region on the Northern Plains.
    
Acting National Transportation Safety Board Chairman Chris Hart says all crude shipments are flammable and a risk to communities and the environment - not just the Bakken oil involved in a string of fiery accidents.
    
Hart cited recent train accidents in Mississippi, Minnesota, Pennsylvania and New Brunswick that involved oil shipments from Canada.
    
His comments were in a letter to U.S. Sens. Ron Wyden and Jeff Merkley obtained Thursday by The Associated Press.
    
The two Oregon Democrats want Transportation Secretary Anthony Foxx to expand a recent order for railroads to notify states of Bakken shipments so that all crude shipments covered.