Most ships carry some caustic soda. It is used in boiler water treatment, in tank and galley cleaning, and as a component of many cleaning chemicals. On board, where space is tight and the deck moves, it needs careful storage and handling. This guide is written for engineers and crew.

Where caustic soda is used on board

• Boiler water treatment: to raise alkalinity and pH in some treatment programmes, and for boil-out of new or repaired boilers.
• Tank cleaning: caustic washes for fatty, oily or organic residues.
• Galley and grease removal: heavy-duty degreasing of ovens, hoods and drains.
• Neutralisation: treating acidic residues after descaling.

Storage on board

• Keep caustic in its original sealed packaging, inside a designated chemical locker, secured against ship movement.
• Store away from acids and separate from food stores.
• Keep it dry. Flakes absorb moisture from humid sea air and cake.
• Keep the safety data sheet in the chemical locker and in the ship's SDS file.

Handling rules

1. Wear splash goggles with a face shield, chemical gloves and a boiler suit or apron.
2. Mix solutions in a stable container that cannot slide or tip. Add flakes slowly to cold water; never water to flakes.
3. Use steel or plastic containers, never aluminium.
4. Label every container of solution.

First aid at sea

Medical help may be hours away, so immediate first aid matters. For eye contact, flush with clean water for at least 15 minutes and continue while seeking radio medical advice. For skin contact, remove contaminated clothing and flush with water for at least 15 minutes. Make sure eyewash bottles or a station are near where caustic is used.

Transport classification

Solid caustic soda is UN 1823, Class 8 (corrosive), Packing Group II under the IMDG Code. Keep the dangerous goods paperwork with deliveries to the ship.

Supplies for vessels in Oman and the UAE

For vessels and ship managers working in Oman, caustic soda flakes 99% are available from ready stock in Barka with next-day delivery within Oman, including to port areas. See caustic soda in Oman for the day's price and documents.

For vessels calling at Fujairah and other UAE ports, DUBI CHEM holds the same flakes as ready stock in Al Hayl, Fujairah, with delivery across the UAE; its caustic soda price in the UAE is published daily in AED.