The Transportation Safety Board of Canada (TSB) recently issued safety advisory letters to Transport Canada and the U.S. Pipeline and Hazardous Materials Safety Administration calling for a review of processes for transporting or importing hazardous materials to ensure the shipment's properties are accurately determined and documented.
The letters comprise the third safety advisory issued by the board concerning the July 6 Montreal, Maine & Atlantic Railway Ltd. (MMA) derailment in Lac-Mégantic, Quebec, and the TSB's ongoing investigation into the accident.
TSB test results show the hazard level posed by the crude oil transported in tank cars on the MMA train was not accurately documented, board members said in a press release. Crude oil is classified as a "Class 3 dangerous good (flammable liquid)," and is further divided into packing groups (PG) to categorize potential hazards, with PG I the most hazardous and PG III, the least.
After analyzing product samples from the nine intact tank cars from the accident, TSB investigators determined the product had the characteristics of a Class 3, PG II dangerous good. But the product was packaged and transported as a Class 3, PG III hazardous product, "which represented it as a lower-hazard, less-volatile flammable liquid," TSB officials said.
"The lower flash point of the crude oil explains in part why it ignited so quickly once the Class-111 tank cars were breached," they said. "Since product characteristics are one of the factors when selecting a container, this also brings into question the adequacy of Class-111 tanks cars for use in transporting large quantities of low flash flammable liquids."
An investigation is ongoing, TSB officials said, adding that further tests are being conducted on the product samples and testing has started on tank-car components. In addition, a review of the relevant regulations and company operating practices is under way.
"These analyses will help determine the safety performance of the tank cars during the accident and to identify any related safety deficiencies," TSB officials said.
The National Transportation Safety Board (NTSB) shares the TSB's concern about accurately documenting haz-mat properties, said NTSB Acting Chair Deborah Hersman in a prepared statement.
"Clearly understanding the hazardous characteristics of what is being transported is one of the keys to safe transportation," she said.
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