Borax (sodium tetraborate decahydrate) is a workhorse of jewellery benches, pottery studios, laboratories and restoration projects. It is not an exotic poison, but it is not harmless either. In Great Britain it is classified as toxic to reproduction, which is why it is supplied for professional use only. This guide explains what the hazard labels mean in practice and how to handle, store and dispose of borax safely at work.
Is borax dangerous? The short answer
Borax does not cause dramatic, immediate harm the way strong acids or solvents can. Its risks are quieter, and they are the reason the controls in this guide matter:
- Eyes: borax dust and solutions cause serious eye irritation.
- Reproductive health: borax is classified Repr. 1B with the hazard statement H360FD, “may damage fertility, may damage the unborn child”. The classification is based mainly on high-dose animal studies, so the aim at work is to keep everyday exposure as low as you reasonably can.
- Dust: high levels of dust can irritate the nose and throat, and dust is the main way borax ends up on skin, in mouths and around a workshop.
With basic controls in place, borax can be used safely. The rest of this guide covers those controls.
What the label on a bag of borax means
Genuine borax supplied in Great Britain carries CLP hazard labelling. Here is how to read it:
| Label element | What it says | What it means for you |
|---|---|---|
| Pictograms | GHS08 health hazard and GHS07 exclamation mark | A long-term health hazard plus an irritant |
| Signal word | Danger | The more serious of the two signal words |
| H360FD | May damage fertility. May damage the unborn child. | Keep exposure low and assess risks for new and expectant mothers |
| H319 | Causes serious eye irritation | Eye protection whenever you handle powder or solutions |
| P201 and P202 | Obtain special instructions before use. Do not handle until all safety precautions have been read and understood. | Read the Safety Data Sheet before first use |
| P280 | Wear protective gloves and eye protection | Nitrile gloves and safety goggles as standard |
| P308+P313 | If exposed or concerned: get medical advice | Speak to a doctor if you are worried about exposure |
| P405 | Store locked up | Keep stock in a locked or restricted store |
The exact wording varies slightly between suppliers, but genuine borax always carries the health hazard pictogram and H360FD. Because of that classification it may not be sold to the general public in Great Britain, although it remains legal for professional, industrial and laboratory use. Our guide Is borax banned in the UK? explains the rules.
Choosing which grade to buy? Our technical grade borax buying guide explains technical, laboratory and pharmacopoeia grades and what a genuine product listing should show.
COSHH: what businesses using borax should do
Borax is a substance hazardous to health, so the Control of Substances Hazardous to Health Regulations 2002 (COSHH) apply when employers and their staff use it. If you work alone, the same steps are still good practice:
- Get the Safety Data Sheet (SDS) and keep it where everyone who uses borax can read it. Section 7 (handling and storage) and section 8 (exposure controls) are the most useful day to day.
- Write a COSHH assessment for each task: who handles borax, how much, how often, and how dust or splashes are created.
- Control exposure in the right order. First ask whether the job needs borax at all: for general cleaning, borax substitute contains no boron. Then use engineering controls such as local exhaust ventilation and wet methods, then safe working practices, and only then personal protective equipment.
- Train and inform everyone who handles borax, including what H360FD means and where the SDS is kept.
- Check that controls keep working, for example that extraction is maintained and PPE is worn and replaced.
- Plan for accidents with a spill procedure, eyewash and first-aid arrangements.
HSE’s COSHH guidance sets out the full duties.
New and expectant mothers
Because borax carries H360FD, employers must take it into account when assessing risks to workers who are pregnant, have recently given birth or are breastfeeding, under the Management of Health and Safety at Work Regulations 1999. Practical measures include taking the worker off tasks that create borax dust, switching to ready-mixed pastes or solutions, or changing duties. Encourage staff to tell you early, and see HSE’s guidance on new and expectant mothers at work.
Workplace exposure limits for borax
HSE’s EH40 table of workplace exposure limits (WELs) sets 8-hour limits for borax dust:
| Form | CAS number | 8-hour WEL |
|---|---|---|
| Disodium tetraborate decahydrate (standard borax) | 1303-96-4 | 5 mg/m³ |
| Disodium tetraborate pentahydrate | 12179-04-3 | 1 mg/m³ |
| Disodium tetraborate anhydrous | 1330-43-4 | 1 mg/m³ |
Treat these as a ceiling, not a target. Good dust control should keep everyday exposure well below them. If you handle large quantities of dry powder, ask a competent person whether air monitoring is needed.
PPE for working with borax
| Protection | What to use | When |
|---|---|---|
| Eyes | Safety goggles, or glasses with side protection | Always, with powder, pastes and solutions |
| Hands | Nitrile gloves tested to EN ISO 374 | Whenever you touch powder, paste or solution |
| Lungs | FFP2 or P2 particulate respirator | When dust cannot be controlled by extraction or wet methods |
| Body | Overalls or a dedicated work coat | When weighing, mixing or cleaning up larger amounts |
Tight-fitting respirators need a face-fit test to protect properly. PPE is the last line of defence, so do not rely on it where extraction or a change of method would remove the dust in the first place.
Safe handling habits
- Open bags carefully and scoop powder rather than pouring it from a height.
- Weigh and mix in one place, ideally under extraction, and away from food and drink.
- Where the process allows, use borax as a paste or solution rather than a dry powder.
- When heating borax as a flux, use extraction at the bench. It bubbles and gives off steam before it fuses; see our borax flux guide.
- Do not eat, drink, smoke or vape where borax is used, and wash your hands before breaks.
- Label any container you decant borax into with the product name and hazard information, and never use food or drink containers.
- Clean benches with a damp cloth. Do not dry-sweep or blow dust away with compressed air.
How to store borax
- Dry, cool and indoors. Damp air makes borax cake, and warm, dry air slowly draws water out of the decahydrate. A cool, dry store keeps it free-flowing.
- Sealed and labelled. Keep it in the original packaging or a clearly labelled, sealed container, and use older stock first.
- Locked or restricted. P405 asks for borax to be stored locked up, out of reach of children and away from food and animal feed.
- Away from strong reducing agents such as metal hydrides and alkali metals, which can react with borax to release flammable hydrogen gas.
Borax is chemically stable and does not go off. Stored this way, it stays usable for years.
Spills and disposal
For a small spill, avoid raising dust: scoop it up or use a vacuum cleaner with a HEPA filter, put it in a labelled container and wipe the area with a damp cloth. Keep spilled material and washing water out of drains, watercourses and soil, because large amounts of boron harm plants.
Waste borax counts as hazardous waste. Send it to a licensed waste contractor, following section 13 of the SDS, rather than putting it in general waste or down the sink.
First aid
| Exposure | What to do |
|---|---|
| Eyes | Rinse with clean water for at least 10 minutes, holding the eyelids apart. Remove contact lenses if this is easy. Get medical advice if irritation persists. |
| Skin | Wash with plenty of water. |
| Dust breathed in | Move to fresh air. |
| Swallowed | Rinse the mouth with water and get medical advice, taking the label or SDS with you. |
| Exposed or concerned, for example during pregnancy | Get medical advice. |
Is borax regulated for transport?
No. Borax is not classified as dangerous goods for road, sea or air transport (ADR, IMDG and IATA), so it can be sent as an ordinary parcel. It still keeps its CLP hazard label.
Borax safety checklist
- SDS read and available to everyone who uses borax
- COSHH assessment written for each task
- Dust controlled by scooping, wet methods and extraction
- Goggles and nitrile gloves worn, with FFP2 where dust remains
- Risks to pregnant and breastfeeding workers assessed
- Stock stored dry, sealed, labelled and locked away
- Spills cleaned without dust, and waste sent to a licensed contractor
Need borax for professional use? Our 99.9% pure borax powder is available in 900g and 3kg packs with an SDS, delivered free to the UK. Certificates of Analysis are available on request through our contact page. For home laundry and cleaning, choose our borax substitute.