North America has seen four oil train disasters in the last month. Trains carrying crude oil have derailed and caught fire. Even before these events, Canadian authorities toughened standards for railroad tank cars. Now they’ve proposed even tighter rules.

Thicker steel walls will be required for tank cars, as well as shields on top and outer thermal “jackets” to protect in case of fire.

Chris Barken, professor and executive director of the University of Illinois Rail Transportation and Engineering Center, says the changes will “make it much less likely to overheat and suffer a thermal tear, such as we’ve seen in a number of these recent accidents.”

Thinner-walled cars were blamed for a Quebec disaster two years ago that killed 47 people. Of the cars that derailed, 94 percent spilled oil that burned.

Canada plans a 10-year phase-in of new tank cars, which strikes some critics as too slow. Critics also say the current oil train safety conversation is too narrow. It’s a complex issue and they want it to include issues of train speed, tracks, bridges, insurance coverage and routes.