An AST developed a leak over the weekend (July 24-25, 2010) during a rail car transfer to an AST. The tentative cause of the release was attributed to a failed gasket (see "Images"). The product spilled into secondary containment constructed of poured concrete but a crack in the containment wall allowed the product to spill onto the property.. The Nickajack Reservoir (Tennessee River) is located approximately 1/4-mi north of the Univar property. An estimated 23,000 gallons of petroleum naphtha was released. The total capacity of the tank is 30,000 gallons. The PRP's clean-up contractor was immediately notified and mobilized to Univar and began collecting spilled product and installed interceptor trenches. Due to the quantity of released product and proximity to the Tennessee River an Region 4 OSC was dispatched to oversee the response.