3-Amino-9-ethylcarbazole (CAS 132-32-1): storage and disposal
Anyone running red immunohistochemistry stains on a pathology or university histology bench will recognise AEC, the chromogen that arrives in a kit with other reagents. It is classified as toxic if swallowed and as a substance that may cause cancer, so the kit that has outlived its use is still a locked-store item, and not simply a box in a fridge.
- CAS number
- 132-32-1
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Acute toxicity
Serious health hazard
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
Kits are the usual form here, which means several small vials from different suppliers and different dates sitting in one box. The chromogen is classified as toxic if swallowed and may cause cancer, so the vial belongs in a locked cabinet with a stock record rather than in the open reagent fridge with antibodies. Segregate the chromogen in accordance with its safety data sheet and the chemical compatibility requirements of other materials in the store. Most labs keep the kit insert with the box. If a kit is split up, label each vial with the name and date it was received, so the chromogen can be identified later.
How to tell it has deteriorated
Few reliable signs show by looking at this chromogen, because no particular visible change is described for it. The checks that matter are on the kit. Look for a vial with a loose or cracked cap, a leaking box, a stained or damp carton, labels that have rubbed off, and expiry dates on the kit insert that passed long ago. A box that has been split up so that the chromogen vial no longer has its name on it is a worse problem than an old one. Any vial with a missing record or unreadable label should be listed rather than opened to see what is inside.
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 code of 16 05 06* fits a research or pathology lab holding the chromogen, and 18 01 06* applies in a human healthcare setting. Check the entry against the way the stock is described before it goes. Write down each vial or kit, the form it is in, how much is left and where it was stored. Because it is classified as toxic if swallowed and may cause cancer, it moves as hazardous waste under a consignment note. Expired kits, part-used vials and any leftover working solution must not go into a sink, general waste or a clinical waste bin. A registered carrier collects it for a permitted facility.
| 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: chromogen kits.
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
- H301 Toxic if swallowed.
- H350 May cause cancer.
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.
- P264 Wash hands and exposed skin thoroughly after handling.
- P270 Do not eat, drink or smoke when using this product.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
Substance as classified, dilutions may differ.
Questions
Can an expired AEC kit go in clinical waste?
No. The chromogen is classified as toxic if swallowed and may cause cancer, so it is chemical waste for specialist collection, not clinical waste. Keep the kit together, labelled, and list each vial.
Where should the chromogen be stored in a histology lab?
In a locked cabinet with a stock record, away from acids and oxidising stock, not loose in the antibody fridge. If the kit insert specifies cold storage, follow that for the kit while keeping the vial controlled and recorded.
How do we tell whether an old chromogen vial is still sound?
There is no reliable visual test. Look at the container: cap, leaks, staining, label and date. If the record is missing or the vial is damaged, list it for collection rather than opening it.
Is a part-used working solution handled the same way?
Treat it as the same waste. It should be kept in a labelled container and listed with the stock vials. Do not assume that a dilute solution is exempt, and do not pour it away.
