Benzoic acid (CAS 65-85-0): storage and disposal
Benzoic acid is held as a white crystalline solid in school and college prep rooms, university labs and pharmacies. It is harmful if swallowed, irritates skin, causes serious eye damage and can damage the lungs through prolonged or repeated inhalation exposure. That last point makes an old jar that is opened again and again a different problem from a jar used once, and it shapes how stock is held and cleared.
- CAS number
- 65-85-0
- Form
- Solid
- Storage class
- Acid
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Corrosive
Harmful or irritant
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 acid 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
Fine white crystals or flakes in a screw-cap jar are the usual form, and a pharmacy cupboard or a prep room shelf are the usual places. Because of the damage to organs from prolonged or repeated exposure, the best storage habit is to open the jar as seldom as possible and keep the lid firmly seated, so dust never builds up on the shelf. Keep it low down on an acid-resistant tray, away from alkalis, oxidisers and toxic stock. In a pharmacy it should not be stored with ingredients used for ointments, which it can be mistaken for. Label and date the jar on arrival.
How to tell it has deteriorated
A dry jar of loose white crystals is normal, and few visible signs of age show up. What matters is the container and what has happened around it: a loose or cracked lid, white dust on the shelf or the outside of the jar, a label that has faded and a jar that has been refilled from another. Clumping suggests damp. Dust on the shelf is worth acting on, because it is escaped material that could be breathed in. A jar that is dusty, unlabelled or undated should be left closed and put on the collection list instead of being opened to check.
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 corrosive acid laboratory pack with compatible chemicals.
As hazardous waste it is grouped with other organic acids and kept away from oxidisers and alkalis. A jar outside a lab pack takes 16 05 08*, and a pharmacy using its own healthcare stream uses 18 01 06*. The reason to be careful is the hazard from prolonged or repeated exposure, so tell the booking team how old the stock is and whether the jar has been opened regularly. It must never go into a sink or drain or into a kitchen or general bin, and it must not be dissolved or neutralised first. Record the amount left and the state of the lid.
| 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
- FlammableOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- AlkaliAcids and alkalis react with strong heat and spattering if they meet.
- OxidiserMany oxidisers release toxic gas or become unstable in contact with acid.
- ToxicToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Named chemicals to keep apart
- AcetoneOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- Ammonia solutionAcids and alkalis react with strong heat and spattering if they meet.
- Calcium hypochloriteMany oxidisers release toxic gas or become unstable in contact with acid.
- EthanolOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- FormalinToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- HexaneOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- Hydrogen peroxideMany oxidisers release toxic gas or become unstable in contact with acid.
- Mercury(II) chlorideToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Show 7 more
- MethanolOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
- Potassium hydroxideAcids and alkalis react with strong heat and spattering if they meet.
- Potassium nitrateMany oxidisers release toxic gas or become unstable in contact with acid.
- Potassium permanganateMany oxidisers release toxic gas or become unstable in contact with acid.
- Sodium cyanideToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Sodium hydroxideAcids and alkalis react with strong heat and spattering if they meet.
- TolueneOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
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.
- H315 Causes skin irritation.
- H318 Causes serious eye damage.
- H372 Causes damage to organs through prolonged or repeated exposure.
Precautionary statements
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- 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.
- 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.
- P317 Get medical help.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P332+P317 If skin irritation occurs: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
- P301+P317 IF SWALLOWED: Get medical help.
- P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P330 Rinse mouth.
- P337+P317 If eye irritation persists: Get medical help.
Substance as classified, dilutions may differ.
Questions
Why does it matter how often a jar of benzoic acid has been opened?
Benzoic acid is classified for lung damage through prolonged or repeated inhalation, so a dusty jar opened many times gives repeated chances to breathe in powder. Keep the lid on, avoid raising dust, and list old stock for collection rather than opening it to look.
Where should it sit in a pharmacy cupboard?
On a labelled shelf low down, away from alkalis, oxidisers and toxic stock, and apart from ointment ingredients it could be confused with. Keep the lid on, date the jar on arrival, and keep it out of food and drink areas.
What does white dust around the jar mean?
It means solid has escaped from a loose or dirty lid, which is the main route to repeated exposure. Do not wipe or sweep it up carelessly. Tell the collector about it and keep the jar closed and upright until it is collected.
