US oil production and energy independence have reached a 28-year high, thanks mainly to fracking in North Dakota. But with no pipelines to move the oil, barrels of crude are now traveling the US on trains – an estimated million barrels a day. Last July, a train carrying barrels of explosive crude oil derailed in Canada. The fiery blast killed 47 people and leveled part of the town. Accidents like this have prompted an outcry over what critics call "bomb trains" and a debate on whether safety regulations are strict enough. We look at the safety issues involved with what critics call "bomb trains."