The Pipeline and Hazardous Materials Safety Administration (PHMSA) today announced it has determined that Federal Hazardous Material Transportation Law preempts the State of Washington's vapor pressure requirement for the transportation of crude oil by rail. 

A study conducted by Sandia National Laboratories concluded that imposing vapor pressure limits would not reduce the risks of transporting crude oil and other flammable liquids by rail.

As part of its decision, PHMSA determined that Washington State’s vapor pressure requirement does not conform to U.S. Hazardous Materials Regulations and is an obstacle to accomplishing and carrying out Federal Hazardous Materials Transportation Law.

Read PHMSA's Preemption Determination for more details.