Two recent fires were investigated in industrial gas oxygen delivery systems that resulted in significant facility damage as well as personnel injury and death. One fire developed in a 6-in. ball valve being utilized as an isolation valve. This fire was kindled while the valve was being opened under a low-pressure differential and resulted in extensive burnout and significant facility destruction. The other fire developed in a 12-in. butterfly valve being utilized as a pipeline isolation and pressurization control valve downstream of an oxygen boost compressor. The valve utilized generally good materials but was vulnerable to ignition and sustained propagation probably due to the presence of an unusual kindling chain. This paper reviews the investigations and analytical work performed during the accident reconstructions and highlights the “lessons learned” from the incidents.