2-Naphthol (CAS 135-19-3): storage and disposal
2-Naphthol, or beta-naphthol, is an off white solid kept in school, college and university stores, most often left over from azo dye practicals. It is harmful if swallowed or inhaled, may cause an allergic skin reaction and is very toxic to aquatic life. The last hazard is the one that governs disposal, and it is the reason a jar that looks quite ordinary is not treated as ordinary waste.
- CAS number
- 135-19-3
- Form
- Solid
- Storage class
- General
- Signal word
- Warning
- Usual EWC code
- 16 05 06*
Harmful or irritant
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 general 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
A glass or plastic jar of pale flakes or powder is the usual form, and it sits comfortably in a dry, labelled store because the storage class is general. Date it on arrival and keep a stock record, since a sensitiser handled loosely in a teaching lab is how skin reactions begin. Put it on a tray so spilled powder is caught, with gloves and a scoop kept near the shelf for this jar alone. Because dust from a leaking cap can be inhaled, a ventilated store suits it better than a closed cupboard. Keep it clear of oxidising stock as you would any organic solid.
How to tell it has deteriorated
Check the cap and label first. Sound stock is pale and loose, in a clean jar with a legible label. Over time air and light take the colour towards tan, grey or brown, usually at the surface first, and jars that have been opened often show it soonest. Caked lumps, a damp feel and powder lodged in the thread show moisture has got in. A label faded by handling, a cap that has fused and a stock entry that no longer matches the jar are the usual problems after a dye practical series ends. A darkened jar is still collected. Record the colour and leave it closed.
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 non-regulated or low hazard laboratory pack with compatible chemicals.
Grouped with compatible organic solids in a lab pack, a jar of this solid is packed in UN approved packaging and travels as UN 3077 under waste code 16 05 06*. A discarded organic chemical outside a lab pack takes 16 05 08*. Because it is very toxic to aquatic life, no trace of it should reach a drain, including rinsings from a beaker or dye bath, and the jar must not go into general waste. Specialist collection is the only route. Write down the colour, the amount and whether the contents are caked.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| 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.
Common quantities we collect
Usually held as: solid.
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.
- H317 May cause an allergic skin reaction.
- H332 Harmful if inhaled.
- H400 Very toxic to aquatic life.
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+P317 IF SWALLOWED: Get medical help.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P317 Get medical help.
- P330 Rinse mouth.
- P391 Collect spillage.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P272 Contaminated work clothing should not be allowed out of the workplace.
- 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.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P333+P317 If skin irritation or rash occurs: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
Substance as classified, dilutions may differ.
Questions
Why does a jar of off white powder get a hazardous waste description?
Because it carries classifications for harm if swallowed or inhaled, for causing an allergic skin reaction and for being very toxic to aquatic life. Its appearance does not change that. It is described accurately and collected by specialist carrier.
What should happen to leftover dye bath liquid from a practical?
It must not be washed away. The substance is very toxic to aquatic life, so washings and residues from the practical are not drain waste. Keep them in labelled closed containers, list what they contain and include them in the collection booking.
The flakes have gone brown. Is the jar still acceptable for collection?
Yes. Darkening comes with air and light and does not stop collection. Record the colour and any caking when you book, and leave the lid on rather than opening it to look.
