Incident Report Subject: Excess Flow Valves - Road & Rail Date of Email reporting Incident: Thu 18/09/2003 Report Detail: Excess Flow Valves - Road & Rail If your emergency plans include the reliance on excess flow control valves to stem the leaking product in an emergency - think again!! revisit your plans and take other alternative mitigation measures should they fail to fully seal the opening following failure of integrity of the system. ---- Source: From the Federal Register: September 4, 2003 (Volume 68, Number 171)] SUMMARY: FRA is issuing Safety Advisory 2003-02 advising all persons involved in loading and unloading products from railroad tank cars that they cannot rely on internal excess flow valves to stop the flow of product except under the limited conditions for which these valves were designed and installed. SUPPLEMENTARY INFORMATION: Factual Background On July 14, 2001, at the XXX Chemicals, Inc., plant in Michigan, a pipe attached to an unloading fitting on a railroad tank car fractured and separated, causing the release of methyl mercaptan, a poisonous, flammable gas. The ensuing fire led to the rupture of hoses on an adjacent tank car containing chlorine, a poisonous, corrosive gas. Before the fire was extinguished about six hours later, three employees in the plant had been killed, and several other employees required treatment for exposure to the chemicals. About 2,000 residents of the area surrounding the plant were evacuated for about 10 hours. In the course of its investigation, the National Transportation Safety Board (NTSB or the Board) determined that a contributing cause of the accident and its severity was the plant's reliance on the tank car excess flow valves \1\ to activate and stop product flow if a hose or unloading pipe broke. |
