o-Dianisidine (CAS 119-90-4): storage and disposal
Old peroxidase staining and enzyme assay methods are the reason a university or pathology store still holds this aromatic amine, often as the dihydrochloride. It is classified as harmful if swallowed and as a substance that may cause cancer. Most bottles are now legacy stock that nobody has used for years, which changes the question from how to use it to how to record it.
- CAS number
- 119-90-4
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Harmful or irritant
Serious health hazard
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
Start with the label. Some bottles are the free base and some are the hydrochloride, and the name on the jar should be written into the stock record exactly as printed. This substance is kept in a locked cabinet with a record, apart from acids and from oxidising stock, in line with the separation of toxic stock in the store. A legacy bottle in a pathology store is best left in its place unless it sits on an open shelf with other reagents. Do not decant it or consolidate half-full jars. Keep it away from food and drink areas, and restrict access to staff who know it is there.
How to tell it has deteriorated
This amine can discolour on standing, but the contents are not something to inspect, so the container is the evidence. Because it is classified as a substance that may cause cancer, nobody should open a jar to look at the contents. Instead check the outside: a dark stain around the cap, powder on the shelf, a cracked or sticky lid, a label that has peeled or lost its name, and a missing stock record. A jar whose supplier label is decades old, or which has no date, should be listed. If there is powder visible outside the glass, keep people away and ask for advice before cleaning anything.
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 We do not publish a drain or general waste route for any chemical.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.
The waste code that normally fits a university lab is 16 05 06*, with 18 01 06* normally used in a human healthcare setting, including a hospital pathology lab. Before collection, write down the exact name on the label, whether it is a hydrochloride, the container size and the state of the lid. Because it may cause cancer, it moves as hazardous waste with a consignment note. Do not open it, tip it out, or put it in a sink or general waste. Old bottles with damaged caps should be reported when enquiring so that a store assessment can be arranged first.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| Human healthcare setting | 18 01 06* |
| 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
- H302 Harmful if swallowed.
- H350 May cause cancer.
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.
- 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.
- 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
Is a bottle of o-dianisidine hydrochloride the same waste as the free base?
It is normally listed under the same entry, but the label name should be recorded exactly, because the description on the paperwork should match the jar. Say which salt or form is on the bottle.
Can we consolidate two part-full jars before collection?
No. Decanting a substance classified as one that may cause cancer creates risk and can mix up records. Keep each jar as it is, labelled and recorded, and list both for collection.
How do we judge an old jar without opening it?
Check the outside only: cap, glass, staining, powder on the shelf, label and date. The contents can discolour on standing but are not something to inspect, so any doubt about the container means asking for assessment.
Is this still used in labs?
It was used in older staining and enzyme methods, and most holders now have only legacy stock. Whether or not a bottle is still wanted, record it and arrange collection instead of leaving it to age in a store.
