Borax (CAS 1303-96-4): storage and disposal
Borax decahydrate sits in school and college prep rooms, university stores and histology laboratories as a white crystalline solid, familiar from slime making. It is classified Danger because it may damage fertility and the unborn child, which is why it belongs with the toxic stock and not on the open shelf with ordinary salts. Many holders treat it as household borax, and that assumption is what a stock check should correct.
- CAS number
- 1303-96-4
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Serious health hazard
What to do this week
- Without moving anything that looks damaged, check the label is readable and write down the opened date if it is not already there.
- Check it is stored as toxic stock, and apart from anything listed under "Do not store with" on this page. If nothing is listed, that does not prove it is safe with everything.
- If you no longer need it, add it to your disposal list so it can be included in a collection.
Safe storage in a school or lab
Possible damage to fertility and the unborn child is the hazard that decides everything: it goes in a locked cabinet with a stock record, away from food and drink areas, and not on the open shelf where a decanted jar might end up. Keep it apart from acids and from other reactive stock, as toxic stock is kept away from both. Label every container with the full name. Because the decahydrate is a familiar white crystal, school stores often hold jars labelled only borax, so check that tubs carry the hazard label and a date of receipt.
How to tell it has deteriorated
A tub of borax decahydrate often looks identical after years, which is the problem. Clear or white crystals may lose some water and turn chalky, and damp may cake them into lumps. Apart from that this substance gives few visible signs, so appearance says little about age. The more telling signs are on the tub: a faded or missing hazard label, a lost stock record and a jar that has been topped up from another source. General checks apply, including cracked containers and an unknown date of receipt. A jar of unlabelled white crystals beside borax should be recorded as unknown.
How it is disposed of
We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a toxic laboratory pack with compatible chemicals.
Before asking for a collection, record the container size, the form, which is decahydrate crystals, whether any jars have been topped up or decanted, and where the stock record is. The reproductive classification is why it is normally described as hazardous waste, usually under entry 16 05 06*, though the producer classifies the waste, and the description should match the label. It must not go into a sink, a drain, a general waste bin or a skip, and nobody should treat it first. Specialist collection packs it with other toxic stock, apart from acids. Keep the tub locked until collection.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| Human healthcare setting | 18 01 06* |
| Usually classed as hazardous waste | Yes |
The code depends on where the waste came from and what it contains, and classifying it is the producer's duty. Use the waste code finder to see why.
Do not store with
- OxidiserToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- AcidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- Acetic acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Hydrochloric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Hydrogen peroxideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities
Usually held as: decahydrate.
Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.
Where it is commonly held
Hazard statements
- H360FD May damage fertility. May damage the unborn child.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P318 If exposed or concerned, get medical advice.
- P405 Store locked up.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Can borax stay on the open shelf in a school prep room?
No. It is classified as capable of damaging fertility and the unborn child, so it belongs in the locked toxic cabinet with a stock record, away from food and drink. Keep it labelled with the full name and the date of receipt.
Can unwanted borax be discarded on site?
No. It must not go into a sink, drain or general waste, and nobody should try to treat it. Keep it in its labelled container, locked away, and arrange specialist collection.
Our borax has turned to a chalky powder. Is that a problem?
Decahydrate crystals can lose some water and become chalky, and it does not change how the stock is classified. Treat it with the same care, keep it labelled and record it as borax in its current form for collection.
