GHENT, W.Va. (AP) - The U-S Chemical Safety Board announced today that a leaky value caused a propane tank to explode at a convenience store in January, killing four people and seriously injuring five others.
The safety board said tests conducted yesterday at a West Virginia laboratory revealed that the liquid withdrawal valve on the tank at the Flat Top Little General Store malfunctioned and leaked.
That led investigators to pinpoint the value as the likely source of the large propane release that exploded.
On the day of the accident, personnel were installing a new propane tank at the store and had removed a metal screw cap on the liquid withdrawal valve, in preparation for removing propane from the old tank.
When operating normally, a spring-loaded actuator prevents the valve from leaking when the screw cap is removed.
Testing also demonstrated that the fill valve, relief valve, and the tank itself do not leak, the safety board said.
Yesterday's testing involved filling the tank with gas and observing the rate of leakage at a range of pressures.