On February 3, 2023, about 8:54 p.m., eastbound Norfolk Southern Railway (NS) train 32N derailed 38 mixed freight railcars at milepost 49.5 on the NS Fort Wayne Line of the Keystone Division in East Palestine, Ohio. Three tank cars carrying flammable and combustible hazardous materials were mechanically breached during the derailment. A fire ignited during the derailment and grew to involve lading released from these three mechanically breached tank cars, additional derailed tank cars carrying both hazardous and non-hazardous materials, and freight cars. Emergency responders established a 1-mile evacuation zone that affected about 2,000 residents.
The derailed equipment included five hazardous materials tank cars carrying vinyl chloride monomer (VCM), a compressed liquified flammable gas offered for shipment as “UN1086 vinyl chloride, stabilized, 2.1.” The five VCM tank cars were not mechanically breached during the derailment, but over the next day, four of these tank cars were exposed to fires and released material from pressure relief devices. These releases ceased on the afternoon of February 4. Acting on information provided by NS and its contractors that a dangerous chemical reaction was occurring within a VCM tank car, the incident commander managing the response chose to expand the evacuation zone and perform a vent and burn (a deliberate breach of a tank car) on all five derailed VCM tank cars. The incident commander was not aware of dissenting opinions the VCM shipper had provided to NS and its contractors. A contractor hired by NS breached the VCM tank cars at 4:37 p.m. on February 6, releasing and igniting their lading.
No injuries were reported during the derailment or emergency response.
We determined that the probable cause of the derailment involving Norfolk Southern Railway train 32N was the failure of the L1 bearing on the 23rd railcar in the consist that overheated and caused the axle to separate, derailing the train and leading to a postderailment fire that likely began with the release of a Class 3 flammable liquid from a DOT-111 tank car that was punctured during the derailment.
Contributing to the postderailment fire and the severity of the hazardous materials release was the continued use of DOT-111 tank cars in hazardous materials service. Also contributing to the severity of the hazardous materials release were:
- the failure of Norfolk Southern Railway and its contractors to communicate relevant expertise and dissenting opinions to the incident commander and
- the inaccurate representation by Norfolk Southern Railway and its contractors that the tank cars were at risk of catastrophic failure from a polymerization reaction, which created unwarranted urgency and led to the unnecessary decision to vent and burn five derailed vinyl chloride monomer tank cars to prevent a polymerization-induced tank car rupture.
Contributing to the exposure of emergency responders and the public to postderailment hazards were:
- Norfolk Southern Railway’s delay in transmitting the train consist information to emergency responders and
- the state of Ohio’s insufficient training requirements for volunteer firefighters.
As a result of this investigation, we issued 34 new recommendations and reiterated 1 previously issued recommendation. We also classified 4 previously issued recommendations.
