1-Naphthol (CAS 90-15-3): storage and disposal
1-Naphthol, also called alpha-naphthol, is a crystalline reagent held in school, college and university stores and in pathology laboratories, where it is kept for reagent work. It causes serious eye damage and may cause an allergic skin reaction, is harmful if swallowed or in contact with skin and may irritate the airways. Its storage class is general, so it often ends up on an ordinary shelf where its hazards are easy to overlook.
- CAS number
- 90-15-3
- Form
- Solid
- Storage class
- General
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Corrosive
Harmful or irritant
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
Serious eye damage and the allergic skin reaction decide how it should be held, even though the storage class is general. Use a labelled place in a dry, well organised store with a stock record, goggles and gloves nearby, and a lid that closes tightly because dust from the crystals may irritate the airways. Keep it on a tray so that spilled powder is caught, and do not leave it out on a bench shelf with the other practical reagents. Dating it on arrival helps, since this substance changes colour with age and the date explains the look of the jar.
How to tell it has deteriorated
Colour is the first thing a technician sees. Fresh naphthol is white to pale, and with air and light it takes on a grey, pink or brown cast, which tends to start at the surface and spread through the jar. Lumps and cakes appear if damp has got in. A lid with powder in its thread, a stained label and a jar whose date or stock entry has gone are the other things worth noting. A darkened jar is no reason to open it. Record the colour, the amount and the label wording, and leave it closed until it is collected.
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.
Waste code 16 05 06* is used when the jar goes in a lab pack, and the asterisk shows hazardous waste, which fits the serious eye damage and sensitiser classification. A discarded organic chemical outside a lab pack takes 16 05 08*, and a pathology laboratory in a human healthcare setting uses 18 01 06*. There is no UN number to quote here. Record the amount, the colour and the label wording. Specialist collection is the only route. It must not be washed away, binned or treated before the carrier arrives.
| 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.
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.
- H312 Harmful in contact with skin.
- H315 Causes skin irritation.
- H317 May cause an allergic skin reaction.
- H318 Causes serious eye damage.
- H335 May cause respiratory irritation.
Precautionary statements
- P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
- P262 Do not get in eyes, on skin, or on clothing.
- P264 Wash hands and exposed skin thoroughly after handling.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P270 Do not eat, drink or smoke when using this product.
- P271 Use only outdoors or in a well-ventilated area.
- P272 Contaminated work clothing should not be allowed out of the workplace.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P317 IF SWALLOWED: Get medical help.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
- P305+P354+P338 IF IN EYES: Immediately rinse with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P316 Get emergency medical help immediately.
- P317 Get medical help.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P332+P317 If skin irritation occurs: Get medical help.
- P333+P317 If skin irritation or rash occurs: Get medical help.
- P361+P364 Take off immediately all contaminated clothing. And wash it before reuse.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P391 Collect spillage.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- 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 1-naphthol the same as its isomer sold as naphthol on older labels?
Not necessarily. Naphthol on an old label can mean either isomer, and they are separate stock lines. Copy the full name and any supplier wording onto the booking so the correct one is described.
Our pathology lab has an old brown bottle of alpha-naphthol. Is it still collectable?
Yes. Darkening is the usual effect of air and light and does not stop collection. Keep the cap closed, record the colour, the amount and where it was held, and book specialist collection.
Why does a general storage class still need goggles nearby?
The class describes shelving, not hazard. This reagent causes serious eye damage and may cause an allergic skin reaction, so protective equipment and a stock record apply wherever it is held.
