On the 22nd November 2016, a vapor flash fire occurred in the Baton Rouge Refinery when operators removed a valve off the alkylation unit, releasing a cloud of isobutane vapor. (Csb.Gov,2017)
On the day of the incident two operators were preparing to put a spare isobutane pump into service, to do so the operators needed to open the pumps inlet valve.
The valve had a gearbox which allowed the operator to have a mechanical advantage in operation, reducing strain, this type of gear box uses gear teeth, “for every quarter turn of the valve handle the gearbox teeth would multiply the movement on the valve” (Paul, 1979).
When operators attempted to open a valve and identified the gearbox was stuck. (Seba,2017)
It was known that the gearbox system could on occasion seize and become hard to open, the accepted practice was to remove the gearbox and use a wrench to open the valve.
97% of the refinery valves had been upgraded, so that gearbox removal did not require line isolation or removal of bolts on line pressure plates, the valve the operators were working on was not an updated model, this meant that to remove the gearbox, they had to remove bolts fixing the pressure plate.
After the plate was removed the operators could open the valve manually and when the valve was opened gas was released via the now open pressure plate.