Sudan black B (CAS 4197-25-5): storage and disposal
Suspected of causing genetic defects, Sudan black B is a dark lipid and myelin stain held as powder and as solution in university, pathology and histology stores. Solutions are often made in ethanol or propylene glycol and form a precipitate on standing. The classification governs who handles it and where it is kept, and the age of any solution decides whether it is still worth keeping at all.
- CAS number
- 4197-25-5
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Warning
- Usual EWC code, laboratory stock
- 16 05 06*
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
Keep Sudan black B in controlled storage and segregate it according to the product safety data sheet and the compatibility requirements of any solvent present. The suspected genetic effect calls for a locked cabinet with a stock record and gloves kept at the cabinet. Powder jars stay tightly closed and dated. Solutions are a separate matter: bottles made up in ethanol need a place away from ignition sources, and those made in propylene glycol do not carry that concern but still need their own label naming the solvent. Never leave a made-up bottle unlabelled on the bench. Black stain on a white shelf is easy to see, so use a tray.
How to tell it has deteriorated
Because the dye is nearly black, its precipitate shows as a gritty deposit at the bottom of a solution bottle, specks on the glass or a dark film at the surface. That is what standing does to these solutions, and it is a reason to list the bottle rather than shake and reuse it. A black crust in the cap thread, a lower level and a label stained dark all show a seal has been leaking or drying out. Powder that has caked or looks damp has absorbed moisture. Few other signs can be relied on, so a lost label or missing date is enough to mark a bottle as unknown.
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 We do not publish a drain or general waste route for any chemical.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.
What to put against each container is the form and the solvent: powder jar, ethanol solution, propylene glycol solution, with sizes, and a note of any heavy sediment. A university or school store would normally use 16 05 06*, and a pathology service clearing human healthcare stock would normally use 18 01 06*. Solutions and powder go as separate lines, because the carrier packs a liquid in ethanol differently from a dry jar. Because the dye is suspected of causing genetic defects, a stained bottle is bagged on its own, and the contents are never put into a sink or a bin.
| 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: solid.
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
- H341 Suspected of causing genetic defects.
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.
Substance as classified, dilutions may differ.
Questions
Why does our Sudan black B solution have a gritty deposit?
A precipitate forms on standing in these solutions. It is not a reason to shake and carry on. Record the date, note the deposit and list heavily affected bottles for collection.
Does the solvent matter for disposal?
Yes. Ethanol-based solutions are packed differently from propylene glycol ones, so say which solvent is on the label. If it is unlabelled, describe the bottle as unknown.
Why must Sudan black B be kept apart from acids and oxidisers?
Oxidisers can react with organic dyes and with some solvents used in stain preparations. Separation from acids depends on the particular product and formulation, rather than being a universal requirement for Sudan black B. Follow the product safety data sheet and account separately for the solvent hazards of prepared solutions.
Which waste code do we use for histology stock?
Human healthcare histology would normally use 18 01 06*, while a school or university store would normally use 16 05 06*. State the setting on the request.
