Carbon tetrachloride (CAS 56-23-5): storage and disposal
Carbon tetrachloride is a legacy solvent still found at the back of older school, college and university stores. It is toxic if swallowed, in contact with skin and if inhaled, suspected of causing cancer, damaging to organs on repeated exposure, harmful to aquatic life and harmful to the ozone layer. It forms phosgene in a fire. Old bottles are the issue, because nobody now remembers why they were bought.
- CAS number
- 56-23-5
- Form
- Liquid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Acute toxicity
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 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
The hazard that decides where it goes is toxicity by every route, so a locked cabinet with a stock record and clear separation from food and drink areas is the minimum. Keep it away from sodium metal, potassium metal, lithium metal and sodium azide: alkali metals can react explosively with chlorinated solvents and azides can form explosive azidoalkanes with halogenated solvents. A bottle that has been in the same cupboard since the last science department refit may be next to exactly those materials, so check neighbours first. Because it forms phosgene in a fire, tell the site fire lead where it is held.
How to tell it has deteriorated
Old carbon tetrachloride is a clear dense liquid, and it does not give a reliable visible warning of age. A technician checks the container: a glass stopper that has frozen in the neck, a cork or plastic cap liner gone brittle, a label so faded that the contents are in doubt, and a level lower than the mark. Stained shelving under a bottle points to a seal that has failed and a leak. Because it is toxic by inhalation, a bottle that smells strongly in the cupboard should be left alone, the room ventilated and the bottle reported rather than opened to look.
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.
Waste code 16 05 06* in our list covers laboratory stock, and a loose discarded organic chemical not sent in a lab pack uses 16 05 08*. Tell the collector it is a legacy solvent, give the bottle size and level, and describe any closure fault. It goes only by specialist collection, grouped with compatible chlorinated organics. It must not be poured into a sink or drain, taken to a tip or left to evaporate in a fume cupboard, and nobody should try to treat it first. A fire risk note about phosgene helps the collector plan.
| 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.
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 hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Hydrochloric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Hydrogen peroxideToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Lithium metalAlkali metals can react explosively with chlorinated solvents.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- Potassium metalAlkali metals can react explosively with chlorinated solvents.
- Potassium nitrateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
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- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- Sodium azideAzides can form explosive azidoalkanes with halogenated solvents.
- Sodium metalAlkali metals can react explosively with chlorinated solvents.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
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
- H301 Toxic if swallowed.
- H311 Toxic in contact with skin.
- H317 May cause an allergic skin reaction.
- H331 Toxic if inhaled.
- H351 Suspected of causing cancer.
- H372 Causes damage to organs through prolonged or repeated exposure.
- H412 Harmful to aquatic life with long lasting effects.
- H420 Causes harm to public health and the environment by destroying ozone in the upper atmosphere.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- 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.
- 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.
- 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.
- P316 Get emergency medical help immediately.
- P318 If exposed or concerned, get medical advice.
- P319 Get medical help if you feel unwell.
- 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.
- 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.
- P502 Refer to manufacturer or supplier for information on recovery or recycling.
- P272 Contaminated work clothing should not be allowed out of the workplace.
- 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
We found an old unlabelled bottle that may be carbon tetrachloride. What now?
Do not open or smell it. Leave it upright on a tray in a ventilated, locked store, record where it was found and what the bottle looks like, and ask for specialist advice before anything is moved or the contents are assumed.
Why is carbon tetrachloride so awkward in a fire?
It forms phosgene in a fire, which is why the fire lead should know where any stock is held. It also harms the ozone layer, so it is never to be released or vented. Collection is by specialists only.
Can it share a cabinet with sodium or potassium?
No. Alkali metals can react explosively with chlorinated solvents. Keep this solvent in a locked cabinet of its own, with a note on the door, and check old cupboards for metals stored beside it.
