Barton Solvents Flammable Liquid Explosion and Fire

On 29 October 2007, just three months after a massive explosion at their Valley Center site, a second fire occurred at the Barton Solvents distribution facility in Des Moines, Iowa. The incident occurred in the "Wholesale Building" while an operator was filling a 300-gallon portable steel tank (commonly known as a "tote") with ethyl acetate, a highly flammable solvent.

The Chemical Safety Board (CSB) identified the "Causal Factor" as a static spark discharge within the tote. Unlike the Valley Center incident, which involved a large fixed storage tank, the Des Moines accident occurred during a manual packaging operation. The operator was using a "splash filling" technique—where the liquid is dropped from the top of the tank through the air—which is a known high-risk manoeuvre for generating static electricity.

The investigation highlighted a critical failure in Bonding and Grounding. Although the operator had attached a grounding clamp to the tote, the CSB found that the electrical connection was ineffective, possibly due to a layer of paint or corrosion on the tote's surface. As the ethyl acetate (a static accumulator) was pumped in, the charge on the liquid surface built up until it jumped to a grounded metal part of the tank or the filling nozzle, igniting the vapour-air mixture in the headspace.

The fire spread rapidly to nearby containers of flammable liquids, causing several small explosions. The CSB was particularly concerned that this occurred so soon after the Kansas disaster, suggesting that the company had failed to implement urgent safety lessons regarding static electricity management across its other sites. This led to a broader industry warning about the dangers of using plastic-lined or improperly grounded metal containers for transferring non-conductive flammable solvents.