Chlorine was released in the liquefaction unit of a chlorine electrolysis plant, due to the rupture of a pipe. During the re-start phase of an electrolysis workshop in a chemical plant, chlorine (Cl2) gas leaked from a pipeline in a confined chlorine liquefaction unit, specifically at the pipeline carrying residual chlorine from the gas/liquid separator to a liquid bleach manufacturing plant.

An explosion occurred in a electrolyzer cell, the vent blew up and caused a pipe rupture on the low pressure chlorine pipeline. The event occurred when two operators were improving the tightness of the diaphragm by injecting a suspension of silica and magnesium chloride or glass fiber. A reaction between hydrogen and chlorine in the cell vapor space was responsible for the explosion. The migration of hydrogen towards the chlorine, producing an explosive mix, was due to excess pressure in the cathodic compartment.