Sodium Hydroxide

Sodium Hydroxide & How To Best Manage First Aid

The Chemical

Sodium Hydroxide Formula - often known as Caustic Soda or lye it has the chemical formula NaOH. It is a co-product of the production of chlorine.

Its Uses

Sodium Hydroxide is widely used in industry. It is used in the production of soap, in water treatment process to control the acidity of water and remove heavy metals. Sodium Hydroxide is used to extract alumina from minerals, to treat metals in the metallurgy industry and in many processes in the food industry. In the home Sodium Hydroxide is present in many drain cleaners due to its ability to break down fats and in oven cleaners.

The Hazards

Sodium Hydroxide is corrosive - even in very dilute solutions. A white solid it is hygroscopic and will react with moisture from the air. When dissolved in water there is a release of heat.

Sodium Hydroxide is a strong alkali, it dissociates completely in an aqueous environment, releasing corrosive OH- ions. Alkalis have a pH greater than 7 on the pH scale.

In contact with the skin, sodium hydroxide can cause liquefactive necrosis with saponification of the cell membranes and dissolution of proteins. Cutaneous lesions often spread to deep skin layers due to the loosening of the planes by liquefaction.

In contact with the eyes, sodium hydroxide rapidly causes corneal opacity. The hydroxide (OH-) ion saponifies the fatty acids and causes the death of the corneal epithelial cells. As the corrosive chemical continues to penetrate the stromal layer and into the anterior chamber, this can lead to lens opacity and in extreme cases destruction of the eyeball. The higher the concentration of the sodium hydroxide solution the faster this penetration will be.

First Aid

To be effective the first aid must stop the corrosion caused by the chemical. If the reactivity of the chemical can be stopped before it penetrates into the deeper layers of the skin or eyes then we can limit the damage caused. 

Water is a polyvalent solution. It's main benefit in a first aid situation is its mechanical washing ability - to sweep the chemical away from the surface of the eyes or skin. This irrigation should start immediately. Emergency water showers installed should conform to EN15154 and have a flow rate of 60 litres per minute. Irrigation should continue for 15 minutes. Due to the lack action on the corrosive nature of the sodium hydroxide, surgical intervention may still be required despite following protocols.


The use of Diphoterine® - an amphoteric chelating agent - not only mechanically removes excess chemical but also actively effects the corrosive OH- ion, binding it to render it harmless and stopping its corrosive action. This promotes a return to a safe physiological pH. In addition, the hypertonic nature of the Diphoterine® solution promotes the drawing out of any penetrated chemical, again rendering it harmless.

For further information download our Sodium Hydroxide booklet:   Sodium Hydroxide

Examples of Diphoterine® Chemical First Aid Decontamination Products:

SIEW/LIS - 50ml Diphoterine® Eye Wash Solution

one of our range of eye washes. Individual eye wash designed to be carried on the person for immediate irrigation of a splash to the eye. Ideal when working at height or in confined spaces where access to first aid can be limited. 


Diphoterine® Chemical Decontamination First Aid station

This First Aid station contains Diphoterine® eye washes, skin sprays and a portable full body shower making it suitable to decontaminate up to a full-body splash. These units are also available in a trolley format (as pictured) ensuring that the first aid response can move with the risk if required.