Little General Store Propane Explosion - US Chemical Safety and ...

Little General Store September 2008
The morning of the explosion, a junior propane service technician 1 (junior technician) from Appalachian
Heating was preparing to transfer liquid propane from an existing tank owned by Ferrellgas to a newly
installed tank 2 owned by Thompson Gas and Electric Services (Thompson). The Ferrellgas propane tank
was installed in 1994 directly against the store’s exterior back wall (Figure 2). At about 10:25 am, the
junior technician, working alone, removed a threaded plug from the liquid withdrawal valve 3 on the
Ferrellgas tank and liquid propane began flowing uncontrollably. Liquid propane sprayed upward,
against the roof overhang, and dense propane gas accumulated at ground level around the tank and the
foundation of the building. Over the next 25 minutes, the escaping propane entered the Little General
store through openings in the roof overhang.
Shortly after the release began, the junior technician called the lead technician to report the release and
seek guidance. At 10:40 am, the junior technician called 911 to report the emergency and summon help.
A captain and two emergency medical technicians from the Ghent Volunteer Fire Department were the
first to arrive, followed by the lead technician and two other emergency responders. Shortly after their
arrival, the propane in the store ignited, leveling it and killing two emergency responders (the fire captain
and one of the emergency medical technicians) and the two Appalachian Heating propane service
technicians.
1
The report discusses the activities of two propane service technicians: a junior technician, who had been
performing propane duties for one and a half months, and a lead technician, who had been performing propane
duties for one and a half years. “Junior” and “lead” are used in this report to differentiate the technicians’ relative
experience in propane service.
2
While commonly referred to as tanks, both of these were 500-gallon pressure vessels. The American Society of
Mechanical Engineers (ASME) publishes the Boiler and Pressure Vessel code; generally, stationary propane tanks
are considered unfired pressure vessels and manufactured in accordance with Section VIII of the code.
3
The liquid withdrawal valve was a RegO Chek-Lok valve model number 7572FC, which is no longer
manufactured. Although the RegO name is still used on propane equipment, the company that manufactured this
valve is no longer in business.
5