Three days after a train derailment in downtown Philadelphia left a load of crude oil dangling over a river, the National Transportation Safety Board on Thursday recommended strict new safety measures for transporting crude oil by rail.

The NTSB’s recommendations to the U.S. Department of Transportation grew out of earlier accidents — notably the disaster last July in Lac-Mégantic, Quebec, when an unattended 74-car train derailed after a downhill run into town, killing 47 people in an explosion and fire. But the potential crisis in Philadelphia might have been avoided under the NTSB proposal.

“The large-scale shipment of crude oil by rail simply didn’t exist 10 years ago, and our safety regulations need to catch up with this new reality,” said NTSB Chairman Deborah A.P. Hersman. “While this energy boom is good for business, the people and the environment along rail corridors must be protected from harm.”

The Association of American Railroads’ annual report on hazardous materials says crude oil shipments by rail have increased by more than 400 percent since 2005 .

The NTSB, an independent federal agency which must rely on Congress and the DOT to implement its proposals, issued three recommendations to the Federal Railroad Administration and the Pipeline and Hazardous Materials Safety Administration (PHMSA).

The first would require more careful route planning by railroads carrying hazardous materials to avoid populated and other sensitive areas. The second would establish an audit program to ensure that rail companies transporting petroleum are prepared to handle worst-case accidents. The third would ensure that hazardous materials are properly classified and that rail carriers have adequate safety and security plans in place.

“If unit trains of flammable liquids are going to be part of our nation’s energy future, we need to make sure the hazardous materials classification is accurate, the route is well planned and the tank cars are as robust as possible,” Hersman said.

Accidents involving flammable liquids that the NTSB has investigated include a Dec. 30 derailment in Casselton, N.D., and a June 2009 derailment in Cherry Valley, Ill. After the 2009 accident, the NTSB issued several safety recommendations to PHMSA that included making tank cars more puncture-resistant and requiring that bottom outlet valves remain closed during accidents.

The DOT is considering rules to improve construction standards for rail cars. Transportation Secretary Anthony Foxx met with rail and oil company executives this month in an effort to lay the groundwork.

Chicago Mayor Rahm Emanuel, speaking Thursday in Washington at the winter meeting of the U.S. Conference of Mayors, endorsed additional federal scrutiny of hazardous material transport by railroads.

“Freight train accidents across the United States should be more than a wake-up call,” Emanuel said. “Railroads are the backbone of our country, providing an economic lifeline to Chicago and communities across the nation. These incidents must move us to take action so we can strengthen safety standards and employ new technology to prevent future harm.”

Emanuel presented several reform proposals, including levying a fee on rail lines that carry dangerous material and using it to pay for rail system enhancements. His plan won the support of several mayors, including Paul Soglin of Madison, Wis.; Sly James of Kansas City; Tom Barrett of Milwaukee; Jim Ardis of Peoria, Ill.; and Michael Nutter of Philadelphia.

Former Pennsylvania governor Edward G. Rendell also weighed in. “As recent unfortunate accidents have shown, there must be a thorough review of existing rail standards and we must advocate for all opportunities to make our communities safer,” said Rendell, who formerly was mayor of Philadelphia and is heavily involved in transportation issues as co-chair of the advocacy group Building America’s Future. “I support the idea of a national hazardous materials freight fee on those who transport hazardous materials throughout our country.”

Some of the six train cars that derailed in Philadelphia on a bridge over the Schuylkill River on Monday carried the same type of flammable crude that exploded in Lac-Mégantic. There were no injuries and no oil was spilled, but the incident above a river and a major expressway, and close to three hospitals and the University of Pennsylvania, renewed questions about the safety of hauling such material through populated areas.

The recommendations released Thursday were issued jointly by the NTSB and the Transportation Safety Board of Canada because railroads operate crude-oil trains across the U.S-Canada border.

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