Thallium(I) sulfate (CAS 7446-18-6): storage and disposal
Also known as thallous sulfate, thallium(I) sulfate is a white, tasteless solid surviving as legacy research stock in university stores. It is fatal if swallowed, damages organs through repeated exposure, irritates skin and is toxic to aquatic life with long lasting effects. Because it has no taste and looks much like common laboratory salts, control of access and an intact record decide how it is handled, and matter more than anything happening in the jar.
- CAS number
- 7446-18-6
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Acute toxicity
Serious health hazard
Hazardous to the environment
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
Fatal if swallowed and with no taste to warn anyone, this salt needs real security around it. Keep it in a locked cabinet, with a stock record that shows quantity as well as name, and with access held by named staff. Ordinary locked store access for a whole department is too loose. Keep it well away from food and drink areas, and away from any shared balance or spatula where traces could pass to other work. Acids and oxidisers go elsewhere. A retiring researcher's cupboard is the classic place to find this kind of thing unrecorded, and any jar found that way should be recorded the same day. Keep the label intact and legible, since the white solid gives no other clue to what it is.
How to tell it has deteriorated
A white crystalline solid in a small jar is what you would see, and old stock is hard to tell from new. Thallium(I) sulfate gives few visible signs with age, so the jar itself carries the useful information. Record a faded label, staining around the cap, caking from damp or a failed seal. Also check the stock record against what is really on the shelf, because a change in the amount with no entry to explain it is a serious finding with this substance. Report it to the person responsible for security at the same time as you report the condition. White traces around the jar or on the tray should be left undisturbed. Nothing about its condition is learned by opening it.
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.
It leaves by specialist collection, and only that way. Between the request and the visit, keep it under the same lock, and confirm the amount against the stock record so that the handover can be reconciled. Describe it by its full name with the word thallium clearly shown, as well as any older name such as thallous sulfate on the label. In a lab pack it is grouped with compatible toxic solids, apart from acids and oxidisers, under 16 05 06*. Keep your copy of the consignment paperwork with the stock record, as that closes the entry. It must not go near a sink, a drain, a general waste bin or a skip, and nobody should attempt to treat it first.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| 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: 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
- H300 Fatal if swallowed.
- H315 Causes skin irritation.
- H372 Causes damage to organs through prolonged or repeated exposure.
- H411 Toxic to aquatic life with long lasting effects.
Precautionary statements
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P264 Wash hands and exposed skin thoroughly after handling.
- P270 Do not eat, drink or smoke when using this product.
- P273 Avoid release to the environment.
- 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.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P332+P317 If skin irritation occurs: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P391 Collect spillage.
- 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
The amount in the jar does not match our stock record. What should we do?
Treat it as a security matter and tell the person responsible for chemical security straight away, because this salt is tasteless and fatal if swallowed. Do not open the jar to weigh it again without advice. Keep it locked, and record what the label and record each say.
We found a jar in a retired researcher's cupboard. How do we deal with it?
Record the jar the same day, with its label wording and location, and move a sound container into the locked toxic cabinet. Check the surrounding bottles as well, since inherited cupboards often hold similar stock, and put everything unwanted on a single list for collection.
Could it be used up in teaching if it is still in good condition?
A salt this toxic is hard to justify for teaching. Good condition does not change that, and it gives few visible signs of age anyway. Any continued use would need your own risk assessment and a named owner, and most holders simply arrange for it to go.