What is sodium hydroxide?
Sodium hydroxide (NaOH) – also known as caustic soda – is an odourless white solid that readily absorbs water from the air. It’s strongly caustic, and can injure anyone who comes into contact with it.
It’s widely used in manufacturing – soaps, paper, rayon, cellophane, mercerised cotton, aluminium and many chemicals – as well as in petroleum refining, degreasing, etching, zinc extraction, tin plating, oxide coating and food processing (for peeling fruit and vegetables). In concentrated form, it’s the active ingredient in drain cleaner.
Health effects
Sodium hydroxide is corrosive, and how badly it injures tissue depends on the concentration and how long the contact lasts. It can burn the eyes, skin and the membranes lining the airways, and at high exposures the damage can be rapid. Airborne alkaline dust is the concern in a workplace setting – which is why measuring how much is in the air matters.
How Airsafe measures sodium hydroxide
Under the work health and safety legislation, air monitoring is required where an employer can’t be reasonably certain that the airborne concentration of a hazardous substance stays below the exposure standard, or where monitoring is needed to gauge the risk to workers’ health. Staying below the workplace exposure standard (which becomes a workplace exposure limit from December 2026) is the legal minimum – good occupational hygiene aims to get exposure as low as reasonably practicable.
Airsafe carries out personal exposure air monitoring over a representative period, using the recognised method for alkaline dusts (NIOSH NMAM 7401). Airsafe is accredited by NATA for volume measurement, so we collect the samples on site using NATA-accredited equipment, then send them to a dedicated NATA-accredited analysis laboratory. All our test reports carry metrological traceability.
We report clearly on what was found and how it compares against the relevant limit, and can advise whether you need to put health monitoring in place. (Health monitoring itself is a medical service we don’t provide – but our air monitoring is what tells you whether it’s required.) Explore our full range of indoor air quality monitoring services.
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Frequently asked questions
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Anywhere caustic soda is handled or generated as a dust or mist – soap, paper and chemical manufacturing, petroleum refining, degreasing and etching, metal plating and extraction, and food processing. The airborne alkaline dust is the workplace concern, and the only way to know how much workers are breathing is to measure it.
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It’s strongly corrosive. It can burn the eyes, skin and the membranes lining the airways, and the severity depends on the concentration and how long the contact lasts. Because the airborne dust is invisible, exposure is easy to underestimate without monitoring.
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We carry out personal exposure air monitoring over a representative period, using the recognised method for alkaline dusts (NIOSH NMAM 7401). Airsafe is accredited by NATA for volume measurement, so we collect the samples on site under our own NATA accreditation, then have them analysed by a dedicated NATA-accredited laboratory – so the results carry metrological traceability. Call us on 1300 888 338 to arrange it.
Contact us about sodium hydroxide monitoring today
If your workers are exposed to sodium hydroxide or other alkaline dusts, monitoring tells you exactly where you stand against the exposure standard.
We work across Sydney, NSW and Australia, with travel built into our quotes for sites further afield.
Contact us for a fast quote on sodium hydroxide monitoring, or call Airsafe on 1300 888 338.
Last updated: July 2026
