National Transportation Safety Board

摘要

The National Transportation Safety Board investigated three accidents that involvedrnhighway vehicles transporting bulk quantities of acetylene gas that occurred between July 25 and October 20, 2007, and reviewed reports of a 2008 overturn accident of another vehicle. The vehicles, called mobile acetylene trailers, carried up to 225 cylinders that were connected by a manifold system and filled with acetylene. Two of the accidents occurred as the vehicles overturned on public highways, in East New Orleans, Louisiana, on October 20, 2007, and in Lamar, Colorado, on June 9, 2008. Two of the accidents occurred while the vehicles were being prepared for unloading, in Dallas, Texas, on July 25, 2007, and in The Woodlands, Texas, on August 7, 2007. In the two overturn accidents, cylinders were ejected from the trailers and damaged, releasing acetylene, which ignited. In one unloading accident, the fire on the initial trailer spread to cylinders on an adjacent trailer; in the other, the fire spread to cylinders on adjacent trailers and to nearby buildings and vehicles. The failures of the cylinders on these mobile acetylene trailers and the resultant damage raised concerns about the accident protection provided by these vehicles, the adequacy of the minimum safety standards and procedures applicable to unloading these vehicles, and the adequacy of fire suppression systems at loading and unloading facilities. To address these concerns, the Safety Board conducted a special investigation of mobile acetylene trailers.