Phosphorus trichloride (CAS 7719-12-2): storage and disposal
A colourless fuming liquid, phosphorus trichloride is held neat in college and university chemistry stores, usually in small glass bottles. It reacts violently with water, releasing hydrogen chloride. It is fatal if swallowed or inhaled, causes severe burns, may corrode metal, and is harmful in contact with skin. Keeping every drop of moisture away decides how a bottle is handled, and an old bottle is often weakest at its closure.
- CAS number
- 7719-12-2
- Form
- Liquid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Corrosive
Acute toxicity
Serious health hazard
What to do this week
- Without moving anything that looks damaged, 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 anything listed under "Do not store with" on this page. If nothing is listed, that does not prove it is safe with everything.
- If you no longer need it, add it to your disposal list so it can be included in a collection.
Safe storage in a school or lab
In a college it normally sits in a locked ventilated cupboard in the chemistry prep room, often in a bottle within a secondary tin or tub that has seen better days. Check that outer container, because metal corrodes readily around this liquid and a rusted tin may be the first thing to fail. A dry, resistant tray with a stock record suits it, clear of food and drink, oxidisers and acids. It must also be away from all water based stock, including ammonia solution, formalin, hydrochloric acid, hydrogen peroxide, sodium hydroxide and sodium hypochlorite, since a leaking neighbour could set off a violent reaction. University holders should watch for bottles that have migrated from a research group to a shared store with no record of who owns them.
How to tell it has deteriorated
Normal stock is a clear, colourless liquid that gives visible fumes in air. Cloudiness or solid matter in the bottle does not fit, and suggests moist air has got in and reaction has started. A crust around the closure, staining on the label and corroded metal nearby point in the same direction. An acid smell in the store is a warning on its own, and it should not be investigated by putting your nose close to the cupboard. Hydrogen chloride can build up pressure in a closed bottle, so a domed cap or a stopper pushed up is a reason to stay clear. If any of these appear, do not open or carry the bottle. Report it and leave it upright.
How it is disposed of
We arrange this by specialist collection. We do not publish a drain or general waste route for any chemical. It is normally packed in a toxic laboratory pack with compatible chemicals.
Waste code 16 05 06* marks this as a hazardous laboratory chemical going in a lab pack, while 16 05 07* would apply to a discarded inorganic chemical moved on its own. Which one is used depends on how it is packed. It is water reactive and is grouped accordingly, kept away from anything aqueous, so state clearly that it is a neat liquid and give the bottle size, closure type and any crust or corrosion. A rusted outer tin should be mentioned too. Specialist collection is the sole route. It must not go to a sink, drain, general waste bin or skip, and adding water or trying to treat what remains is prohibited, even when only a small amount seems to be left.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded inorganic chemical, not a laboratory pack | 16 05 07* |
| Usually classed as hazardous waste | Yes |
The code depends on where the waste came from and what it contains, and classifying it is the producer's duty. 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.
- Ammonia solutionReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Calcium hypochloriteToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- FormalinReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Hydrochloric acidReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Hydrogen peroxideReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Nitric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
- 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 hydroxideReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Sodium hypochloriteReacts with water, releasing heat and often a flammable or corrosive gas, so keep it away from all water based stock.
- Sulfuric acidToxic stock is stored apart from acids. Several toxic salts release toxic gas in contact with acid.
Common quantities
Usually held as: neat.
Tell us the container size and how many you hold. An estimate is enough to start with, and some items cannot be priced until someone has looked at them.
Where it is commonly held
Hazard statements
- H290 May be corrosive to metals.
- H300 Fatal if swallowed.
- H312 Harmful in contact with skin.
- H314 Causes severe skin burns and eye damage.
- H330 Fatal if inhaled.
- H373 May cause damage to organs through prolonged or repeated exposure.
- EUH014 Reacts violently with water.
- EUH029 Contact with water liberates toxic gas.
Precautionary statements
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- 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.
- 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.
- P301+P330+P331 IF SWALLOWED: Rinse mouth. Do NOT induce vomiting.
- 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.
- 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.
- P363 Wash contaminated clothing 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.
- P234 Keep only in original packaging.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P302+P352 IF ON SKIN: Wash with plenty of water.
- P317 Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P390 Absorb spillage to prevent material damage.
- P406 Store in corrosive resistant container with a resistant inner liner.
Substance as classified, dilutions may differ.
Questions
Only a little is left in the bottle. Can we let it fume off in the fume cupboard?
No. Do not evaporate it or try to use it up, however small the remainder. It is fatal if inhaled, and its fumes also attack fittings. Keep the bottle closed and upright on its tray, and list it for a specialist collection with an estimate of the amount.
The outer tin around the bottle has rusted. Should we replace it?
Do not transfer the bottle yourself. Rust shows acid fumes have been escaping, so the closure may be weak and lifting it could break a fragile seal. Leave it in place and mention the rust when you arrange collection, so the packing can allow for its condition.
Nobody knows who owns the bottle in our shared store. What now?
Write down the label, the location and the condition, and add it to the stock record under the store manager. An unclaimed bottle of something fatal if inhaled should not wait for an owner to appear. Ask for it to be included in the next collection.
