A cloud of chlorine gas was accidentally generated around 10.30 am while transferring hydrochloric acid (HCl) into a tank containing sodium hypochlorite (NaClO or liquid bleach) in a chemical wholesale company.

The accident happened during a period of rebuilding of the unit; the filling station and the delivery station were in the process of being renewed. At the delivery station for tankers there only one connection for all chemicals but FeCl3. A pump transports the fluids via pipe to a connection battery / filling station for drums. At the battery, a worker connects the pipe, by using a hose, to the right tank. The technician chose the wrong tank at this point. Realizing his mistake, he stopped the transfer operation thus limiting the quantity of chlorine released to 200 kg. The employee was severely poisoned and died a month later.

The police stopped traffic in the industrial area and the residents within a perimeter of 200 metres were required to stay indoors for 2 hours. 54 people were treated by around 120 fire-fighters.

Further to this accident, the unit is rearranged:

• The delivery station for roadtankers was equipped with a separate filling pipe for hypochlorite. The adapter was equipped with left hand threads (mistake-proofing?).
• All adapters of the storage unit were locked off and keys will be released after analysis by the laboratory personnel.
• All connections were clearly labelled.
• The hypochlorite pipe is monitored by a pH-electrode.

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