Abstract: Employee #1, a caster, was doing semicontinous casting of a copper alloy when the south billet of tank #21 started to leak at the bottom of the mold. Employee #1 noticed the leak and called over Employee #2, the foreman. With both employees present, the molten metal in the billet came into contact with the water in the casting tank, resulting in an explosion. Employees #1 and #2 both sustained burns to the face, neck, hands, abdomen, and legs. Prior to the explosion, the foreman assumed that Employee #1 had stopped the downcast. However, Employee #1 had in fact not stopped the downcast, and, as a result, the billet was not fully formed.