NTSB Report on North Dakota Derailment Renews Push to Replace Aging Tank Cars

The NTSB's final report, released Thursday, determined that the July 5, 2024 derailment of a CPKC train near Bordulac, North Dakota was triggered by a culvert that collapsed beneath the train, breaking a rail. While the culvert had been inspected regularly, the NTSB found those inspections were not thorough enough to detect the collapse risk. After 29 cars left the tracks, methanol leaked from five breached DOT-111 tank cars and ignited, and the resulting fire then caused three tank cars carrying anhydrous ammonia to breach as well. The NTSB emphasized that the DOT-111 cars' tendency to rupture on impact dramatically amplified the consequences of the derailment, and noted that even some upgraded successor cars remain inadequate due to thin outer shells. No injuries occurred during the derailment itself, though a small number of cleanup workers later sought medical treatment after exposure to anhydrous ammonia, and only two nearby homes required voluntary evacuation. The NTSB also called on railroads to change train assembly practices to prevent flammable liquids from being placed adjacent to toxic inhalation hazards. Congress has mandated replacement of DOT-111 cars for flammable liquid transport by 2029, but the cars could still legally carry other hazardous materials beyond that deadline.