Benzidine (CAS 92-87-5): storage and disposal
A bottle of benzidine in a school, college or pathology store is almost certainly an old one. It is a known human carcinogen and its manufacture and use are heavily restricted, so any stock found is legacy stock. It carries a danger signal word and is classified as harmful if swallowed, may cause cancer, and very toxic to aquatic life with long lasting effects.
- CAS number
- 92-87-5
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Harmful or irritant
Serious health hazard
Hazardous to the environment
What to do this week
- 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 the items listed under "Do not store with".
- If you no longer need it, add it to your disposal list so it goes on the next collection.
Safe storage in a school or lab
The aim with a legacy bottle is to leave it as found. Do not open it, handle it more than needed, or carry it across the building to a better cupboard. If it is in a locked toxic store already, keep it there with the door locked and add it to the stock record, noting the location and label wording. Stock of this class sits apart from oxidising stock, because a reaction could release toxic vapours, and apart from acids. A bottle in an old pathology storeroom or a school chemical cupboard should be separated from neighbours by distance rather than by moving it. Keep access limited, and make sure nobody tries to clear the shelf around it.
How to tell it has deteriorated
Visible change in the contents is not described for this substance, and with a known human carcinogen the aim is to keep away from them. Judge from outside the container only. A cracked bottle, a perished or sticky cap, powder on the shelf or the outside of the glass, a label that cannot be read, an old supplier label from decades ago, or a bottle that has been moved and lost its record are all reasons to stop and ask for help, not to investigate. Do not open it, wipe it down or tip a sample onto paper to check. If there is any sign of leakage, keep people away from the shelf.
How it must be disposed of
By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a toxic laboratory pack with compatible chemicals.
A bottle like this is recorded in place: the name as it appears on the label, the size of the container, the state of the cap and glass, and the exact room and shelf. Its waste code is 16 05 06*, with 18 01 06* in a human healthcare setting. Because it is a known human carcinogen and legacy stock, nobody should open or handle it, and a store assessment before collection is sensible. It must not be moved around the site, put in a sink or the general bin, or treated in any way. Say clearly that it is old stock when enquiring. A registered carrier collects it as hazardous waste under a consignment note.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| Human healthcare setting | 18 01 06* |
| Hazardous waste | Yes |
The code depends on where the waste came from and what it is mixed with. 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 we collect
Usually held as: legacy stock.
Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.
Where it is commonly held
Hazard statements
- H302 Harmful if swallowed.
- H350 May cause cancer.
- H410 Very toxic to aquatic life with long lasting effects.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- 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+P317 IF SWALLOWED: Get medical help.
- P318 If exposed or concerned, get medical advice.
- P330 Rinse mouth.
- 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
We found an old bottle of benzidine in a store. What should we do first?
Leave it where it is and do not open it. Note the label, the container condition and the location, restrict access to that shelf, and send an enquiry that says it is legacy stock.
Can we move it to the locked toxic cabinet?
Do not move it unless it is unavoidable and safe. Advice should be sought first. If it is already in a locked store, keep it there and record it. Handling an old bottle more than needed adds risk.
Why is this treated more carefully than ordinary reagents?
It is a known human carcinogen and its manufacture and use are heavily restricted. Stock held now is legacy stock, so the priority is to avoid opening or handling it and to arrange an assessment.
Does it matter that it is very toxic to aquatic life?
Yes, it is one reason it never goes near a drain or general waste. Any spillage or residue is dealt with by specialists. The aquatic classification sits alongside the cancer classification and does not change the route.
