BILLINGS, Mont. — Disclosures from railroads about volatile oil shipments from the Northern Plains show dozens of the trains passing weekly through Illinois and the Midwest and up to 19 a week reaching Washington state.

The Associated Press obtained details on the shipments Tuesday under public-records requests filed with state emergency officials.

Details on the shipments were turned over to states under an order from the U.S. Department of Transportation. That came after fiery accidents including a derailed oil train last July in Quebec that killed 47 people.

BNSF Railway reported that 11 oil trains traveled through King County during a weeklong stretch from May 29 to June 4, while 10 passed through Snohomish County during the same time period.

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The largest number of oil trains — 19 — went through Klickitat County along the Columbia River during that week.

Railroads had sought to prevent the public disclosure of the information, citing security concerns.

Some states have agreed to requests from BNSF, CSX and Union Pacific to keep the information confidential. Those include California, New Jersey, Minnesota and Colorado.

But the Federal Railroad Administration determined the information is not sensitive information that must be withheld from the public to protect security.

The light, sweet crude from the Bakken oil fields in the Northern Plains is more volatile than many other types of oil. It’s been involved in most of the major accidents as the crude-by-rail industry rapidly expanded during the past several years.

Each train can carry 3 million gallons of the fuel, and the order covers all shipments of a million gallons or more.

U.S. crude-oil shipments by rail topped a record 110,000 carloads in the first quarter of 2014. That was the highest volume ever moved by rail, spurred by the booming production of shale oil from the Northern Plains and other parts of the country, according to the Association of American Railroads.

Some of that oil makes its way to refineries in Washington and Oregon.

Earlier this month, Gov. Jay Inslee directed the state to put together a detailed review of the safety and spill risks associated with the enormous growth in delivery of oil by train and barge.

This story includes material from Seattle Times archives.