On December 30, 2013, a BNSF train derailment caused 476,000 gallons of crude oil to spill and ignite near the town of Casselton, North Dakota. There were no fatalities or serious injuries but 1,500 people were evacuated from their homes.
Recently the National Transporatation Safety Board determined that the cause of the derailment was due to a broken axle to one of the tanker cars. NTSB investigators found a void in the middle of the axle which was used previously on another railcar. As a result of this investigation, the NTSB now requires more stringent testing of these secondhand-use railcars such as the railcar involved in this derailment. Safety is no accident. Source