NTSB completes documentation of derailed tank cars

The National Transportation Safety Board (NTSB) yesterday announced completion of its investigation into the performance of DOT-117 tank cars involved in the Dec. 22, 2020, derailment of a BNSF Railway Co. oil train near Custer, Washington.

The NTSB conducted a limited investigation of the accident, focused solely on the performance of the tank cars, so the board did not determine a probable cause for the derailment, or publish a brief or report. The investigation documentation of the tank car performance is available in a factual report.

No injuries were reported in connection with the derailment; however, 120 people were evacuated near the accident site and about 29,000 gallons of crude oil was discharged from three tank cars. The oil ignited and burned uncontrolled for two hours. Damage was estimated to exceed $1.5 million.

In its report, the NTSB states nine of the 10 derailed tank cars were originally constructed to DOT-111A100WI specifications, with enhancements to the Association of American Railroads CPC-1232 industry standard for crude oil and ethanol service tank cars ordered after Oct. 1, 2011. The CPC-1232 tank cars were converted to DOT-117R100W in 2019.

“Because our investigation was limited to data collection, we have not issued any findings or safety recommendations. The data we gathered in this investigation will assist us as we evaluate the performance of tank cars carrying flammable liquids involved in other rail accidents," said Robert Hall, director of the NTSB’s Office Railroad, Pipeline and Hazardous Materials Investigations, in a press release.

Ensuring the safe shipment of hazardous materials was an item on the NTSB’s 2019-20 Most Wanted List of Transportation Safety Improvements to highlight the need for replacing DOT-111 and CPC-1232 tank cars with the more robust DOT-117 design.