On March 3, the Pipeline and Hazardous Materials Safety Administration published a safety advisory concerning the manufacture and use of composite cargo tank motor vehicles operating under a special permit (SP). The notice references a catastrophic failure of a cargo tank manufactured in accordance with SP 11903 on Dec. 30, 2009. The failure was caused by loading the tank with incompatible materials. The advisory is a reminder of the requirement to conduct testing to ensure that the material transported is compatible with the tank.