Chemical safety

Sodium hydroxide: hazards and COSHH prompts

The standard strong base; dissolving pellets generates significant heat.

Always work from your own safety data sheet. Classification varies with grade, concentration and supplier. Use this page to orient yourself, then assess the task you are actually doing, at the scale you are actually doing it.

Hazard classification

CAS: 1310-73-2
Formula: HNaO
Molecular weight: 39.997
Signal word: Danger

GHS pictograms

Hazard statements

H290May be corrosive to metals
H314Causes severe skin burns and eye damage
H315Causes skin irritation
H318Causes serious eye damage
H319Causes serious eye irritation
H335May cause respiratory irritation
H370Causes damage to organs

Precautionary statements (28)

P234Keep only in original container.
P260Do not breathe dust, fume, gas, mist, vapours or spray.
P261Avoid breathing dust, fume, gas, mist, vapours or spray.
P264Wash hands thoroughly after handling.
P264+P265Wash hands thoroughly after handling. Do not touch eyes.
P270Do not eat, drink or smoke when using this product.
P271Use only outdoors or in a well-ventilated area.
P280Wear protective gloves, protective clothing, eye protection and face protection.
P301+P330+P331IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
P302+P361+P354IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
P302+P352IF ON SKIN: Wash with plenty of water.
P304+P340IF INHALED: Remove person to fresh air and keep comfortable for breathing.
P305+P354+P338IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
P308+P316IF exposed or concerned: Get emergency medical help immediately.
P316Get emergency medical help immediately.
P317Get medical help.
P319Get medical help if you feel unwell.
P321Specific treatment — see the safety data sheet.
P332+P317If skin irritation occurs: Get medical help.
P337+P317If eye irritation persists: Get medical help.
P362+P364Take off contaminated clothing and wash it before reuse.
P363Wash contaminated clothing before reuse.
P390Absorb spillage to prevent material damage.
P403+P233Store in a well-ventilated place. Keep container tightly closed.
P405Store locked up.
P406Store in a corrosion-resistant container with a resistant inner liner.
P501Dispose of contents and container in accordance with local, regional and national regulations.

Classification data from PubChem CID 14798 , retrieved automatically and refreshed weekly. PubChem aggregates from multiple suppliers; entries can differ from the SDS for your grade.

What your COSHH assessment has to answer

Based on the hazard classes above. These are prompts, not answers — the right control depends on your task, your quantities and your room.

Because it is acutely toxic

Which exposure route is credible for your task — inhalation, skin, or both?
Is containment engineered (fume hood, cabinet) rather than relying on PPE?
What is the first-aid response, and is the material for it actually at the point of use?
Is lone working with this restricted?

Because it burns or irritates skin and eyes

Is eye protection specified for the actual task, including splash risk when pouring?
Are the gloves rated for this substance and this contact time?
Where is the nearest eyewash, and when was it last flushed and checked?

Because it can damage organs

Is the exposure repeated or long-term rather than one-off?
Is there an exposure limit to design the controls around?
Are users told what early symptoms look like and who to report them to?

Stop rebuilding this by hand

Keep Sodium hydroxide — and everything else — in one inventory.

LevelSixLabs pulls GHS classification onto your chemical records automatically, then builds COSHH assessments from the substances you already hold. Explore a fully-stocked demo lab, no signup.

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