Caustic soda should be handled with greatest care

In the latest edition of its Safety Digest, the UK MAIB presents a case of a serious injury of a chief officer on board a chemical tanker, providing a description of what happened and important lessons learned, to prevent similar accidents from occurring in the future. A C/O was seriously injured on board due to caustic soda which splashed into his face, entering under the edge of his protective mask. If the PPE does not fit, is not suitable for purpose, or cannot be worn for some reason, stop the work until proper protection can be provided, UK MAIB says.   

 The incident

The chief officer on a loaded chemical tanker was attempting to clear a cargo line blocked with frozen 50% caustic soda liquor (freezing temperature +12°C). There were two other crew members assisting him on deck. They were wearing full alkali protection suits with goggles and face masks. Due to the strong wind, they had all found it difficult to keep the hoods of their suits in place and so had removed them.

Finding that the caustic soda could not be cleared by blowing the line through with compressed air with the drain valve open, the chief officer poured warm water over the line to melt the liquor. A large slug of caustic soda ejected through the drain valve and hit the drip tray under it. It rebounded off the tray and splashed the chief officer, entering under the edge of his protective mask and onto his face. He immediately wiped his face with the sleeve of his jacket, however this was already contaminated and his goggles came off in the process. He suffered serious burns to his face and complained of blurred vision and a burning sensation in his eyes.

The coastguard was informed and within a short time he was airlifted to the nearest hospital. Unfortunately, the chemical had entered his eyes, resulting in total loss of vision in both eyes.

Lessons learned

1.       Caustic soda is an extremely corrosive substance and should be handled with the greatest care. When solid caustic soda comes into contact with water it produces a significant amount of heat (exothermic reaction).

2.        PPE should be considered the last defence against accidents. A thorough evaluation of the risks involved should always be carried out before undertaking all potentially hazardous tasks.

3.       If the PPE does not fit, is not suitable for purpose, or cannot be worn for some reason, stop the work until proper protection can be provided. Do not compromise your safety by continuing without effective PPE.