Sodium cyanide (CAS 143-33-9): storage and disposal
Sodium cyanide is legacy stock in most college and university stores, often left over from past teaching or research. It is rapidly fatal by all routes and very toxic to aquatic life, and it releases hydrogen cyanide gas with acids and, more slowly, with moist air. Those reactions decide how it is handled: always locked and dry, well away from every acid, and listed for specialist collection instead of being kept indefinitely.
- CAS number
- 143-33-9
- Form
- Solid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Corrosive
Acute toxicity
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 toxic 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
Check what is on the other side of the shelf wall. A locked toxic cabinet is no use if it stands next to the acid store, or if acid fumes or a damp wall can reach it, because moist air is enough to start releasing hydrogen cyanide. Nitric, hydrochloric, hydrobromic and perchloric acids all need their own space, well apart. Calcium hypochlorite, hydrogen peroxide and chromium trioxide must also stay away, as cyanides react violently with those oxidisers. Keep it dry and always locked, with a stock record that shows when it was last seen. Over time, cyanide also attacks metal, so corroded metal shelving or a rusted cap are reasons to report it. A named key holder matters more here than for almost any other stock.
How to tell it has deteriorated
A damp container is the first concern, followed by a faded label and a stained or corroded cap. Sound stock is free flowing white solid, so caked or damp material means moist air has got in, and that is also when hydrogen cyanide starts to form. Some people report a bitter almond or ammonia-like smell near old stock, but not everyone can smell cyanide, so smell is not a reliable test and nobody should sniff a bottle to check. Do not open a caked container or try to break up the contents. Staining on the shelf and a missing stock record are also worth reporting. If the container is damp or smells, close the cabinet, keep people out of the room and get specialist help before going further.
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 toxic laboratory pack with compatible chemicals.
Grouping is the crux. It has to be packed well away from every acid and oxidiser in a collection, because contact in a damaged pack would release hydrogen cyanide, so give an exact description and do not leave it on a mixed list called old toxic salts. Specialist collection is the only route. Nobody should attempt to destroy it with bleach or any other chemical, and it must not go into a sink, a drain, a general waste bin or a skip. Record the quantity, the label wording, whether the solid is caked or damp, and who holds the key. Code 16 05 06* generally fits college and university stock. A hazardous waste consignment note, or special waste in Scotland, is the paperwork for the movement.
| EWC code, laboratory chemicals | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| 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
- 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 hypochloriteCyanides react violently with strong oxidisers.
- Chromium trioxideCyanides react violently with strong oxidisers.
- Hydrobromic acidCyanides release highly toxic hydrogen cyanide gas with acids.
- Hydrochloric acidCyanides release highly toxic hydrogen cyanide gas with acids.
- Hydrogen peroxideCyanides react violently with strong oxidisers.
- Hydroiodic acidCyanides release highly toxic hydrogen cyanide gas with acids.
- Nitric acidCyanides release highly toxic hydrogen cyanide gas with acids.
Show 10 more
- Perchloric acidCyanides release highly toxic hydrogen cyanide gas with acids.
- Phosphoric acidCyanides release highly toxic hydrogen cyanide gas with acids.
- Potassium chlorateCyanides react violently with strong oxidisers.
- Potassium dichromateCyanides react violently with strong oxidisers.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Potassium permanganateCyanides react violently with strong oxidisers.
- Sodium chlorateCyanides react violently with strong oxidisers.
- Sodium dichromateCyanides react violently with strong oxidisers.
- Sulfuric acidCyanides release highly toxic hydrogen cyanide gas with acids.
- Trichloroacetic acidCyanides release highly toxic hydrogen cyanide gas with acids.
Common quantities we collect
Usually held as: legacy stock.
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
- H290 May be corrosive to metals.
- H300 Fatal if swallowed.
- H310 Fatal in contact with skin.
- H330 Fatal if inhaled.
- H410 Very toxic to aquatic life with long lasting effects.
Precautionary statements
- P234 Keep only in original packaging.
- P260 Do not breathe 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.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P284 In case of inadequate ventilation wear respiratory protection.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- 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+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- 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.
- P320 Specific treatment is urgent (see supplemental first aid instruction on this label).
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P332+P317 If skin irritation occurs: Get medical help.
- P337+P317 If eye irritation persists: 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.
- P390 Absorb spillage to prevent material damage.
- P391 Collect spillage.
- P403+P233 Store in a well-ventilated place. Keep container tightly closed.
- P405 Store locked up.
- P406 Store in corrosive resistant container with a resistant inner liner.
- P501 Dispose of contents and container in accordance with local, regional, national and international regulations.
Substance as classified, dilutions may differ.
Questions
Can bleach be used on old sodium cyanide before it is collected?
No. Attempting to destroy it with bleach or any other chemical is exactly what must not happen, as the reactions can release toxic gas and the outcome cannot be verified. Keep it locked and dry, and list it for specialist collection in its original container.
We can smell almonds near the cabinet. Is that a leak?
It may be. Treat any such smell as a warning, but do not rely on it, because not everyone can smell cyanide and its absence proves nothing. Keep people away from the room, do not open the cabinet and call for specialist help.
The solid has caked into a lump. Is it still dangerous?
Yes. Caking points to moisture and possibly some breakdown, but the material remains rapidly fatal by all routes. It also means hydrogen cyanide may have been released into the container. Do not chip it or open it. Describe its condition when you arrange collection.
