Static discharge the cause of Oklahoma fire, NTSB report concludes
Published: 01 January, 2008
A report published by the United States National Transportation Safety Board (NTSB) that looked into the major fire that took place on April 7th, 2003 in Oklahoma, has discovered it was caused by static discharge.
An 80,000-barrel floating roof storage tank exploded and then burned while it was being filled with diesel at a petroleum product storage terminal. The fire burned for 21 hours and damaged two other nearby storage tanks, and schools and residents were evacuated for two days. There were no injuries or fatalities but the amount of lost oil amounted to nearly two million dollars.
The fire was thought to have initially been caused by a lightning strike but the investigation discovered the causes included an improper procedure for switching the content of the tank from gasoline to diesel oil and an unsafe filling procedure. Because the flow rate of material into the tank was too high, and the tank level too low, the incoming liquid discharged into the vapour space of the tank and caused static electrical discharge in the tank vapour space and so creating a flammable atmosphere.
