A 0.8m wide steel conveyor belt in the tunnel transported sugar from two of the silos into an elevator system that
conveyed the sugar to the packaging area. Concerned the contaminants might fall onto the refined sugar on its way for
packaging the engineers decided to fully enclose the conveyor belt and its assembly. By enclosing the conveyor belt the engineers s prevented the fine sugar dust from dispersing into a wider volume of air. Investigators later concluded that the concentration of sugar dust in the enclosed conveyor belt system belt up to such a levelthatit exceeded the minimum explosible concentration