Sodium sulfide (CAS 1313-82-2): storage and disposal
Sodium sulfide is held in school, college and university stores as nonahydrate crystals or flakes, often in a tub with a smell that warns of trouble. It is a strongly alkaline solid classified as toxic by swallowing and skin contact, as causing severe burns and as very toxic to aquatic life. Its worst habit is releasing hydrogen sulfide, which is toxic.
- CAS number
- 1313-82-2
- Form
- Solid
- Storage class
- Alkali
- 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 alkali 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
Acids must be kept apart from sodium sulfide, and it should not sit among general salts near them. If an existing arrangement puts acids near an old or compromised container, get competent advice before rearranging the stock. Sodium sulfide releases toxic hydrogen sulfide on contact with acid, so hydrochloric, nitric, sulfuric, phosphoric, perchloric, hydrobromic, hydroiodic and trichloroacetic acids stay in a different cabinet. It also releases the gas slowly with moist air, so the cap must seal and the shelf must be dry. It sits low down on a resistant tray in a corrosive store, away from oxidisers, with a locked cabinet and a stock record because of its toxicity. Do not attempt to loosen a stuck cap on an old container. Record the condition and request specialist assessment.
How to tell it has deteriorated
A smell of rotten eggs near the shelf means hydrogen sulfide is escaping, and the nose is a poor guide because at high exposures the smell can fade, so a lack of smell proves nothing. Flakes that look damp or sticky, a cap fused to the thread, a crust, yellowed or darkened crystals and staining of the label are the visible signs. Nobody should open an old tub to look inside it. A tub with no date of receipt is treated as old stock, and the same goes for one whose crystals have slumped into a single mass at the base.
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 alkali laboratory pack with compatible chemicals.
Specialist collection is the only route, and never a sink, drain or general waste, since it is very toxic to aquatic life and can release gas. Record the form (nonahydrate or flakes), the quantity and the state of the cap. Acid must never be added to it to use it up. The inorganic chemical code applies outside a lab pack. The collection supplier must assess the container condition and arrange compatible segregation from acids and oxidisers. An old container associated with a rotten egg smell needs specialist assessment before anyone attempts to handle or pack it.
| 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
- AcidAcids and alkalis react with strong heat and spattering if they meet.
- OxidiserSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
Named chemicals to keep apart
- Acetic acidAcids and alkalis react with strong heat and spattering if they meet.
- Calcium hypochloriteSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Hydrobromic acidSulfides release toxic hydrogen sulfide gas with acids.
- Hydrochloric acidSulfides release toxic hydrogen sulfide gas with acids.
- Hydrogen peroxideSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Hydroiodic acidSulfides release toxic hydrogen sulfide gas with acids.
- Nitric acidSulfides release toxic hydrogen sulfide gas with acids.
- Perchloric acidSulfides release toxic hydrogen sulfide gas with acids.
Show 5 more
- Phosphoric acidSulfides release toxic hydrogen sulfide gas with acids.
- Potassium nitrateSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Potassium permanganateSome oxidisers react strongly with alkalis, and ammonia based stock is especially at risk.
- Sulfuric acidSulfides release toxic hydrogen sulfide gas with acids.
- Trichloroacetic acidSulfides release toxic hydrogen sulfide gas with acids.
Common quantities we collect
Usually held as: nonahydrate, flakes.
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
- H301 Toxic if swallowed.
- H311 Toxic in contact with skin.
- H314 Causes severe skin burns and eye damage.
- H400 Very toxic to aquatic life.
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.
- P273 Avoid release to the environment.
- P280 Wear protective gloves, protective clothing, eye protection and face protection.
- P301+P316 IF SWALLOWED: Get emergency medical help immediately.
- P301+P317 IF SWALLOWED: Get medical help.
- P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P302+P361+P354 IF ON SKIN: Take off immediately all contaminated clothing. Immediately rinse with water for several minutes.
- 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.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P361+P364 Take off immediately all contaminated clothing. And wash it before reuse.
- P363 Wash contaminated clothing before reuse.
- P390 Absorb spillage to prevent material damage.
- P391 Collect spillage.
- 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
Why does sodium sulfide smell of rotten eggs?
It releases hydrogen sulfide with acid and slowly with moist air. The smell can fade at high exposures, so never judge safety by smell. Keep it closed and away from acids.
Which acids must it be kept away from?
All of them, including hydrochloric, nitric, sulfuric, phosphoric, perchloric, hydrobromic, hydroiodic and trichloroacetic acids. Store the acids in a different cabinet from the sulfide, not merely on a different shelf.
Our old tub has a stuck cap and damp flakes. What now?
Leave it closed, do not force the cap, record the condition and request collection. Damp flakes and a stuck cap suggest moist air has reached the contents.
