A CSX train carrying Bakken oil derailed and erupted into flames in West Virginia on Monday, adding to the growing debate about the safety of transporting crude on America's railroads. The crash is the second in 10 months involving a CSX train, carrying oil from North Dakota.
"It is not safe to transport oil by train, full stop, period," said Eric de Place, policy director for Sightline Institute, a sustainability-focused research firm in Seattle.
Monday's train derailment affected two counties, and forced some West Virginia residents to flee their homes in winter weather as power cut out and drinking water was threatened.
In a statement, CSX said it was working with first responders and federal, state and local officials on the oil train derailment near Mount Carbon, West Virginia. One person was being treated for possible respiratory problems, but no other injuries were reported.
The cause of the derailment is under investigation. But CSX said all of the oil cars were newer CPC 1232 models—not older model tank cars criticized for being prone to puncture.
But Sightline's de Place said most oil cars have design gaps, including walls that are too thin. "They're riddled with design flaws," de Place said. Oil cars also travel too fast, he added.
The Association of American Railroads, the trade group, said freight railroads have employee training and operating procedures that govern handling and movement of crude oil. Federal rules and self-imposed safety practices dictate train speeds, according to the association's website.
Despite the industry's efforts, the explosion of oil production in the Bakken formation—and America's appetite for cheap energy—are pushing up against America's rail system. Some portions of that infrastructure date back decades, when builders had no idea the rails would one day transport hundreds of thousands of crude oil a day.
Ripple effect of Bakken shale oil
The bulk of oil transported on America's rails is from the Bakken formation—a large source of oil that straddles North Dakota, and portions of Montana and Canada.
The oil is buried deep in the ground, and hydraulic fracturing, or fracking, forces natural gas and crude oil out of the shale buried deep below the earth by using highly pressurized and treated water.
The region's fracking boom has generated jobs and boom towns, and transformed the region into acres of grasslands now dotted with natural gas flares that are visible from space.
Read MoreInside North Dakota's latest fracking problem
While there's some pipeline capacity to ship the shale oil, the main transport option is America's railroads.
In 2013, U.S. railroads moved 11 times more crude oil than all the oil moved by train from 2005 to 2009, according to data from an American Association of Railroads report published in late 2013. Measured another way, railroads shipped an estimated 425,000 rail carloads of crude oil—that's roughly 815,000 barrels per day.
Push for revised safety standards
Prior testimony suggests even newer oil car models adopted by the industry in 2011 may not be sufficient.
Testifying before the National Transportation Safety Board, NBC News reported Robert Fronczak, assistant vice president of environment and hazardous materials for the Association of American Railroads, said the most updated standard adopted by the industry in 2011 is "no longer adequate."
More from NBCNews: Read MoreNew oil cars may not be safe enough
CSX operated another oil train that derailed and caught fire in Lynchburg, Virginia last April.
That freight train originated from the Bakken shale in North Dakota was run by CSX Transportation, CSX's principal operating company. The parent firm, CSX Corp., is based in Jacksonville, Florida.
Train car safety has become a hot issue following oil train accidents, including a crash in July 2013 that killed 47 people in Quebec.
Said de Place of Sightline: "We're just not prepared for this, at the local or federal levels."