Caustic soda (sodium hydroxide) is one of the most useful chemicals in industry and cleaning, and one of the most common causes of chemical burns at work. It does not smell, it does not fume, and a splash can look harmless for a few seconds before it starts to burn. This guide covers safe handling, storage, first aid and spill response for workplaces in Oman that use caustic soda flakes.
Know the hazard
- Corrosive to skin and eyes. Caustic burns can go deep, and eye contact can cause permanent damage or blindness.
- Harmful if swallowed or inhaled. Dust from flakes irritates the nose, throat and lungs.
- Releases heat with water. Dissolving flakes can make the solution boil and spit.
- Reacts with some metals. Aluminium, zinc and tin are attacked, releasing flammable hydrogen gas.
- Transport class: UN 1823, Class 8 (corrosive), Packing Group II.
Personal protective equipment
- Eyes: splash goggles; add a face shield when mixing or pouring solutions.
- Hands: chemical-resistant gloves suitable for alkalis.
- Body: apron or chemical suit, long sleeves, closed boots.
- Breathing: a dust respirator where flakes are handled in quantity or ventilation is poor.
Safe handling rules
- Always add flakes to water, slowly and while stirring. Never pour water onto flakes.
- Use cold water when making solutions, and let hot solutions cool before moving them.
- Use stainless steel or suitable plastic containers. Never use aluminium buckets or galvanised tanks.
- Label every container of caustic solution with the contents and strength.
- Never store caustic solutions in drinks bottles or unlabelled containers.
- Keep acids and caustic apart, in storage and in use.
Storage
Store bags sealed, on pallets, in a dry, covered and ventilated area, away from acids, metals such as aluminium and zinc, and sources of moisture. Caustic soda absorbs water and carbon dioxide from the air, so reseal opened bags immediately. In humid coastal areas and during the khareef in Dhofar, this matters even more.
First aid
- Eyes: remove contact lenses if easy. Flush with plenty of water for at least 15 minutes, holding the eyelids open. Get medical attention immediately.
- Skin: remove contaminated clothing and shoes. Flush the skin with plenty of water for at least 15 minutes. Get medical attention.
- Inhalation: move the person to fresh air. If breathing is difficult, give oxygen if trained to do so, and get medical help.
- Swallowing: do not induce vomiting. Never give anything by mouth to an unconscious person. Get medical help immediately.
Make sure an eyewash station or a supply of clean water is within a few seconds' reach of every place where caustic is handled.
Spills
For small spills of flakes, sweep up carefully with suitable tools into a labelled waste container, avoiding dust. Residues can be neutralised with a dilute solution of a weak acid such as acetic acid, then rinsed. For large spills, keep people away, stop the leak if it is safe, prevent the material from entering drains, and call for specialist help.
Get the full safety data sheet
Every workplace that uses caustic soda should keep the safety data sheet (SDS) where the product is stored and used. You can download the full caustic soda safety data sheet for caustic soda flakes 99%, along with a sample certificate of analysis, from Muscat Chemical, which supplies caustic soda from ready stock in Barka with next-day delivery across Oman. In the UAE, the same SDS and COA are available from DUBI CHEM in Fujairah.
