Don C. Brunell

North Dakota Gov. Jack Dalrymple has announced new rules that reduce the vapor pressure in oil tanker cars leaving his state’s booming oil patch. The goal is to reduce the risk of fiery explosions like the one that killed 47 people in Lac-Megantic, Quebec in July 2013.

In separate efforts, Congress is beefing up safety standards for oil tank cars and the White House is calling for increased rail inspections and slower speeds for oil trains traveling through populated areas.

Meanwhile, the Washington legislature is working to tighten regulations on oil trains and establish a per-barrel tax to b...