Thorium dioxide (CAS 1314-20-1): storage and disposal
Thorium dioxide is a heavy white radioactive oxide, held as legacy stock in schools, colleges and universities. Bottles often date back many years and may be labelled thoria. It is toxic if swallowed, inhaled or in contact with skin, and it may cause cancer. Fine powder is the main concern on a shelf, and radioactive status settles the route, so your Radiation Protection Adviser decides what happens next.
- CAS number
- 1314-20-1
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
Acute toxicity
Serious health hazard
This chemical is a manual enquiry
This is radioactive. Radioactive materials have their own regulations, which can require a permit or registration, and they need a specialist route, so we look at each one individually.
Thorium compound, radioactive.
It cannot be priced through a form. Please do not open or move it. Call us or send an enquiry and we will talk through the next step, which depends on what it is. Keep following your own procedures for controlled drugs, radioactive materials, gases and asbestos.
What to do this week
- Leave it where it is. If it looks old, crystalline or damaged, do not open or move it and keep people away from the shelf. If there is immediate danger, such as a leak, fumes or a fire, leave the area and call 999.
- Write down the label wording, the rough age and where it is stored, from a safe distance.
- Send us those details, and a photo if you can take one without touching it.
Safe storage in a school or lab
Fine white powder in an old glass bottle or a small tin is the form you usually come across, and it can feel surprisingly heavy for its size. Sometimes the label reads thoria. Keep it where it is, labelled and with a record of holding, in a locked space away from food and drink, and do not decant it. Powder escaping as dust is the concern, as it is toxic if inhaled and may cause cancer, so a bottle with a loose lid is not one to tighten or shake. Because it is so inert chemically, nothing on the shelf is likely to react with it, and that can make it easy to overlook. Tell your adviser where it is.
How to tell it has deteriorated
A white powder in an unmarked bottle is what you see first, and it looks like dozens of ordinary oxides on the same shelf. That is the real trouble with it. It is chemically very stable, so thorium dioxide gives almost no visual signs of ageing, and its radioactive status does not fade over any working lifetime. Check what you can see of the container: a split tin, a brittle lid, white dust on the shelf or a label reduced to fragments. Any bottle with the word thoria or thorium on it should be reported, whatever the condition. Do not wipe up the dust around it, and do not open an unknown bottle to work out what it is.
How it is disposed of
This does not go through our standard collection route. It is arranged by manual enquiry, and never goes down the drain or into general waste.
Looking up a waste code for thorium dioxide leads nowhere useful. It is radioactive material, so permitting rules and your Radiation Protection Adviser decide its route, not a code on a chemical list. A university may also involve its Radioactive Waste Adviser. It falls outside a chemical collection and it is not quoted online. We can take a manual enquiry to help you pull the details together, and a store assessment is recommended, but do not add the bottle to a lab pack list. What your adviser needs is the label wording, the rough amount and the state of the container. It stays labelled and where it is, and nobody should move it or try to make it safe.
| Usually classed as hazardous waste | Yes |
|---|
No List of Waste code is given here. The waste is outside the chemical collection stream and is assessed by manual enquiry.
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.
Common quantities
Usually held as: legacy stock.
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
- H301 Toxic if swallowed.
- H311 Toxic in contact with skin.
- H331 Toxic if inhaled.
- H350 May cause cancer.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P262 Do not get in eyes, on skin, or on clothing.
- P264 Wash hands and exposed skin thoroughly after handling.
- P270 Do not eat, drink or smoke when using this product.
- P271 Use only outdoors or in a well-ventilated area.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P316 Get emergency medical help immediately.
- P318 If exposed or concerned, get medical advice.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P361+P364 Take off immediately all contaminated clothing. And wash it before reuse.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- 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
What does the old name thoria mean on a bottle in our store?
Thoria is the older name for thorium dioxide. If that is the word on a label, report it as a radioactive item, even if the contents look like any other white oxide. Keep the bottle closed and in place, and pass the exact label wording to your adviser.
How do we deal with white dust on the shelf around the bottle?
Leave it, and keep people away from that shelf. It could be the oxide escaping, which is toxic if inhaled and may cause cancer, so wiping or brushing is not appropriate. Tell your Radiation Protection Adviser what you can see and let them decide how it should be cleared.
It is chemically stable, so could it stay in the cupboard indefinitely?
Stability is not the deciding factor. It remains radioactive material with a record of holding to maintain, and a forgotten bottle can eventually be disturbed by someone unaware of it. Your adviser can say whether it should stay under control for now or be removed, and how that should be done.
