On February 16, 2007 a massive propane release occurred at the Propane Deasphalting Unit (PDA) of the Valero-McKee Refinery near Sunray, Texas. The resulting vapor cloud ignited, burning four workers, destroying the PDA, and causing significant knock-on damage to adjacent pipe racks and equipment. The US Chemical Safety and Hazard Investigation Board (CSB) investigation determined that water trapped in a piping dead-leg froze during cold weather, cracking a 10 '' diameter liquid propane line, and causing the initial release when warmer weather returned. The CSB identified dead-leg identification and management, freeze protection, emergency isolation capability, and structural steel fire protection as key issues contributing to the incident. Two near-misses were associated with this incident; the release of over 2.5 tons of chlorine from containers adjacent to the PDA, and the inability of workers to access manual deluge valves protecting a nearby LPG storage sphere, which was impacted by the fire. The CSB made recommendations to Valero, the American Petroleum Institute, the McKee Refinery, and the United Steelworkers and their local. (C) 2010 American Institute of Chemical Engineers Process Saf Prog 29: 322-331, 2010