Hart's comments were contained in a letter to U.S. Sens. Ron Wyden and Jeff Merkley obtained by The Associated Press. They add to growing pressure on federal regulators to improve oil train safety in the wake of repeated derailments, including in Lac-Magentic, Quebec, where 47 people were killed in a massive conflagration.
Transportation Secretary Anthony Foxx last month ordered railroads to notify states of Bakken oil shipments so firefighters and first responders can better prepare for future accidents.
But Wyden and Merkley told Foxx Thursday that his order leaves emergency personnel in the dark on oil shipments from outside the Bakken or smaller than the 1,000,000 gallon threshold set by Foxx.
The Oregon Democrats urged an expansion of the order to cover crude from all parts of the U.S. and Canada, and to lower the threshold to include smaller shipments.
"With the exception of the Lac-Megantic accident, every accident involving crude oil, ethanol and other flammable materials since 2006 has resulted in a hazardous materials release of less than 1,000,000 gallons," Wyden and Merkley wrote in a Thursday letter to Foxx. They said the examples cited by the NTSB chairman show trains that carry non-Bakken crude and less than 1,000,000 pose the same "imminent hazard" that Foxx has asserted for Bakken oil.
Representatives of the oil industry and officials in North Dakota also complained about Bakken oil being singled out by regulators although for opposite reasons. The American Petroleum Institute and American Fuel and Petrochemical Manufacturers have said Bakken oil is no more volatile than other light, sweet crudes produced elsewhere in the U.S. and abroad.
The concerns aired by the NTSB and the Oregon senators essentially flip that argument on its head, to say different types of crude and other hazardous liquids such as ethanol also pose a significant safety risk.
"Accidents involving crude oil or flammable liquids of any kind, especially when these liquids are transported in large volumes, such as in unit trains or blocks of tank cars, can have disastrous consequences," Hart said.
Association of American Railroads spokeswoman Holly Arthur said the rail industry is complying with Foxx's original order. She said the group would have to see the specifics of any changes before commenting on them.
About 700,000 barrels of oil a day enough to fill 10 trains of 100 cars each is coming out of the Bakken by rail, according to the North Dakota Pipeline Authority. That equals roughly 80 percent of crude-by-rail shipments nationwide during the first three months of the year, according to an analysis of information provided by the railroad association.