The accident occurred during the maintenance of a sulfuric acid storage tank in an industry for the fertilizers production. The maintenance works consisted in cutting operations (to remove some plates fastened with bolts) by using oxyacetilenic flame on the storage tankOn the internal surface of a tank containing sulfuric acid a corrosion phenomenon associated with the accumulation of hydrogen occurred owing to poor maintenance. The hydrogen was then ignited by the oxyacetylenic flame. The explosion hurled the tank over a hangar, demolishing two other tanks (also containing sulfuric acid) and causing the escape of the product which invaded the basin of containment. The two men who were performing the cutting operation died. The released sulfuric acid evaporated from the basin originating a toxic cloud which dispersed without consequences for the population. The basin invaded by the sulfuric acid was emptied and neutralized with sodium carbonate in order to avoid that sulfuric acid could corrode the ammonia pipings inside the basin itself.