But restricting that information violates the state's public records law, so the state has not signed documents from the rail companies seeking confidentiality, said Mark Stewart, a spokesman for the Washington Military Department's Emergency Management Division.
The U.S. Department of Transportation issued an emergency order last month requiring railroads by Friday to notify state officials about the volume, frequency and county-by-county routes of trains carrying 1 million or more gallons of crude oil from the Bakken region of North Dakota, Montana and parts of Canada.
Federal transportation officials said they expected the states "to treat this data as confidential, providing it only to those with a need-to-know, and with the understanding that recipients of the data will continue to treat it as confidential." That includes emergency workers who need access to the information to form response plans.
BNSF Railway and Union Pacific Railroad last Friday sent the state confidentiality agreements aiming to restrict the information to emergency response groups for planning purposes only. The companies called it "security sensitive."
Stewart said the state Emergency Response Commission sought legal advice and determined that those agreements "require us to withhold the information in a manner that's not consistent with the state public records act."
The commission instead presented alternative agreements to the railroads, noting that the information may be subject to disclosure. That proposal said a state official would notify the railroads if the public sought the information so the companies could seek a protective order or other remedy.
Courtney Wallace, a spokeswoman for BNSF Railway, said Wednesday that the railway is reviewing that proposal.
She said the company would comply with the federal order but believes the information is "considered security sensitive and confidential, intended for people who have 'a need to know' for such information, such as first responders and emergency planners."
The state commission last month approved a plan to post the information online. But Stewart said Wednesday that the data would be posted only after any legal issues from a disclosure request are resolved.
The federal order applies to railroad carriers with trains carrying roughly 35 tank cars or more of oil.
Late Tuesday, Union Pacific Railroad told the state it does not transport Bakken crude oil trains at the order's reporting threshold. Company spokesman Aaron Hunt said Union Pacific moves 163,000 carloads of crude oil across its national network, and less than 1 percent comes through Washington.
In Washington, crude oil shipments went from zero in 2011 to 17 million barrels in 2013, according to rough state estimates. Those numbers are likely to increase if proposed oil terminals at the ports of Grays Harbor and Vancouver and at the state's refineries get built.
Earlier this year, some state lawmakers and groups unsuccessfully pushed for legislation that would give the public information about oil train movements through their communities.