Arsenic (CAS 7440-38-2): storage and disposal
Arsenic survives in some school, college and university stores as lumps of legacy stock, often in a jar older than the staff who look after it. It is classified as toxic if swallowed or inhaled, a skin irritant and very toxic to aquatic life. The usual problems are a missing label, a missing record and nobody sure who last opened the jar.
- CAS number
- 7440-38-2
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Acute toxicity
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
Check that the jar is where the stock record says it is, because legacy arsenic jars can go astray. It is toxic if swallowed or inhaled, so it belongs in a locked cabinet with a stock record, away from food and drink areas, acids and oxidising stock. Arsenic can react with strong oxidisers and with some acids to give toxic products, so a shared cabinet with either is a poor arrangement. Keep the lumps in a tightly closed, labelled container and do not decant them into smaller jars. Anything without a label should be left closed and reported, not guessed at.
How to tell it has deteriorated
Start with the label and the record, since old arsenic jars lose both. The element tarnishes in air, so lumps that were bright grey may now look dull or darkened on the surface, which is expected on legacy stock. Look for a cracked jar, a perished lid, powdery residue in the bottom or round the neck, staining on the shelf and a missing date of receipt. Loose powder or dust in the jar suggests the lumps have been disturbed and is worth recording before anyone handles the container. If the label has gone or cannot be read, leave the jar closed and ask for a specialist assessment.
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 We do not publish a drain or general waste route for any chemical.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.
Legacy arsenic is packed by the collector in its own compatible group, apart from acids and oxidising stock, because packing follows what could react and not the order of the shelf. The usual entry is 16 05 06*, though the producer classifies the waste. Nobody should try to crush, heat or dissolve the lumps, and they must not go down a sink or drain, into a general bin or into a skip. Specialist collection is the only route. Record the form, the amount, the state of the jar, whether the label is legible and what is known of its history.
| 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: lumps, 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.
- H315 Causes skin irritation.
- H331 Toxic if inhaled.
- H410 Very toxic to aquatic life with long lasting effects.
Precautionary statements
- P261 Avoid breathing 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.
- P271 Use only outdoors or in a well-ventilated area.
- P273 Avoid release to the environment.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P316 Get emergency medical help immediately.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P391 Collect spillage.
- 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.
- P203 Obtain, read and follow all safety instructions before use.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P317 Get medical help.
- P318 If exposed or concerned, get medical advice.
- P332+P317 If skin irritation occurs: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
Substance as classified, dilutions may differ.
Questions
We found an unlabelled jar that may be arsenic. What should we do?
Leave it closed and in place, keep the area clear and do not try to identify it by opening or testing. Record where it was found and what the jar looks like, then send a collection enquiry so a specialist can assess it.
Does arsenic need a locked cabinet?
Yes. It is classified as toxic if swallowed and toxic if inhaled, so it is held in a locked toxic cabinet with a stock record, away from food and drink areas, acids and oxidising stock. The record should show who holds it and when it was last checked.
Can arsenic lumps be broken up or washed before collection?
No. Nobody should crush, wash or otherwise process legacy stock before it leaves. Keep it in its closed container, in the locked cabinet, and describe the form and condition accurately when you ask for a collection.
