NTSB issues five recommendations in report on West Virginia rail tank car incident

Washington — The Pipeline and Hazardous Materials Safety Administration’s “failure to establish a final tank car specification for poison/toxic inhalation hazard tank cars and an aggressive schedule for removing nonconforming tank cars from service” jeopardizes safety among fleets, the National Transportation Safety Board concluded in its investigation of a chlorine release from a ruptured rail tank car in West Virginia.

In a final report issued Feb. 14, NTSB states that a 42-inch crack developed on the tank shell of a Department of Transportation Specification-105 rail tank car after it was loaded with 178,400 pounds of liquefied compressed chlorine on Aug. 27, 2016, at the Axiall Corp.’s Natrium plant. As a result, the entire load spilled out over two-and-a-half hours and formed a vapor cloud that migrated south along the Ohio River valley near New Martinsville. Eight people were injured.

In the report, NTSB issued five recommendations, including three calling on PHMSA to:

• Promulgate a final standard that includes enhanced fracture toughness requirements for tank heads and shells for pressure tank cars used to transport poison/toxic inhalation hazard materials.
• Prohibit use of tank cars transporting poison/toxic inhalation hazard materials that are constructed of non-normalized steels and are not constructed of steels meeting the highest available fracture toughness specifications.
• Issue maintenance guidance for owners of DOT-105 pressure tank cars transporting poison/toxic inhalation hazard materials to establish structural integrity inspection frequency; critical flaw size, repair and acceptance criteria for indications in fracture-sensitive locations; and nondestructive testing methods to detect and identify cracks.

To the Association of American Railroads:

• Ensure local post-weld heat treatment processes are sufficiently monitored to avoid damage to tank car materials from uncontrolled heat treatment after welding and repairs.

To the American Railcar Industries Inc.:

• Develop inspection and maintenance procedures to address cracks in cradle pad weld attachments applicable to pressure tank cars equipped with ACF-200 stub sill underframes.