On July 17, 2007, at about 9 a.m., an explosion and fire occurred at the Barton Solvents Wichita facility in Valley Center, Kansas. Eleven residents and one firefighter received medical
On July 17, 2007, at about 9 a.m., an explosion and fire occurred at the Barton Solvents Wichita facility in Valley Center, Kansas. Eleven residents and one firefighter received medical treatment. The incident triggered an evacuation of Valley Center (approximately 6,000 residents); destroyed the tank farm; and significantly interrupted Barton’s business. An investigation by the U.S. Chemical Safety and Hazard Investigation Board (CSB) has concluded that the initial explosion occurred inside a vertical above-ground storage tank that was being filled with Varnish Makers’ and Painters’ (VM&P) naphtha. VM&P naphtha is a National Fire Protection Association (NFPA) Class IB flammable liquid that can produce ignitable vapor-air mixtures inside tanks and, because of its low electrical conductivity, can accumulate dangerous levels of static electricity.
• NONCONDUCTIVE FLAMMABLE LIQUIDS CAN ACCUMULATE STATIC ELECTRICITY DURING TRANSFER & STORAGE.
• STATIC SPARKS CAN READILY IGNITE FLAMMABLE VAPOR-AIR MIXTURES INSIDE STORAGE TANKS.
• MATERIAL SAFETY DATA SHEETS (MSDSS) OFTEN DO NOT ADEQUATELY COMMUNICATE HAZARD DATA AND PRECAUTIONS.
1. Stop-start filling, air in the transfer piping, and sediment and water (likely present in the tank) caused a rapid static charge accumulation inside the VM&P naphtha tank.
2. The tank had a liquid level gauging system float with a loose linkage that likely separated and created a spark during filling.
3. The MSDS for the VM&P naphtha involved in this incident did not adequately communicate the explosive hazard.