ortho-Phthalaldehyde (CAS 643-79-8): storage and disposal
Ortho-phthalaldehyde, usually called OPA, is a high level disinfectant used in clinics and dental surgeries, typically as a 0.55% solution. As a classified substance it is toxic if swallowed, causes severe skin burns and eye damage, may cause an allergic skin reaction, and is very toxic to aquatic life. A ready-to-use solution may be less hazardous than the pure substance, so read the product label as well. It is a sensitiser and it stains.
- CAS number
- 643-79-8
- Form
- Solution
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code
- 16 05 06*
Corrosive
Acute toxicity
Serious health hazard
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
The hazard that decides where it goes is its toxicity combined with skin and eye damage, so store it in a locked cabinet with a stock record, away from food and drink areas and from acids and oxidisers. A reaction with an oxidiser could release hazardous vapours. In a dental surgery or endoscopy room it often lives on a shelf by the washing area, which is the wrong place, since any splash will stain what it touches. Use a tray under the container, keep the cap on, and wear gloves and eye protection for moving it. Date each container when it is opened and keep a note of the strength.
How to tell it has deteriorated
The first thing a technician sees is staining. OPA marks skin, gloves, labels and clothing grey-black, so a grey-black smear on a shelf, a tray or the outside of a bottle shows that liquid has escaped. Look around the neck and cap for residue, and look for a bottle that has lost level without being used. A faded label matters more than usual, because staining can make the strength unreadable. Check for cracked plastic, a swollen container and a missing stock record. A bottle that is leaking or heavily stained should go in a tray, and anyone who touches it needs gloves.
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.
Use the waste code that fits the holder: 18 01 06* in a human healthcare setting such as a dental surgery or clinic, and 16 05 06* or 16 05 08* elsewhere. The point that decides how it is handled is the damage it does to aquatic life, so used or unwanted disinfectant is never tipped down the sink and no one should try to deactivate it first. Give the collector the strength on the label, the container size and whether it has leaked, since stained outsides call for gloves. It goes in a lab pack with compatible liquids to a permitted facility, collected by a registered carrier.
| 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
- 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.
- 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.
- Potassium permanganateToxic and oxidising stock are stored apart. A reaction could release toxic vapours.
- 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: 0.55% disinfectant.
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.
- H314 Causes severe skin burns and eye damage.
- H317 May cause an allergic skin reaction.
- H335 May cause respiratory irritation.
- H373 May cause damage to organs through prolonged or repeated exposure.
- H410 Very toxic to aquatic life with long lasting effects.
Precautionary statements
- P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- P240 Ground and bond container and receiving equipment.
- P241 Use explosion-proof electrical, ventilating and lighting equipment.
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P261 Avoid breathing 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.
- P271 Use only outdoors or in a well-ventilated area.
- P272 Contaminated work clothing should not be allowed out of the workplace.
- 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+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.
- P319 Get medical help if you feel unwell.
- P321 Specific treatment (see supplemental first aid instruction on this label).
- P330 Rinse mouth.
- P332+P317 If skin irritation occurs: Get medical help.
- P333+P317 If skin irritation or rash occurs: Get medical help.
- P362+P364 Take off contaminated clothing. And wash it before reuse.
- P363 Wash contaminated clothing before reuse.
- P370+P378 In case of fire: Use suitable extinguishing media to extinguish.
- P391 Collect spillage.
- 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.
Substance as classified, dilutions may differ.
Questions
Where should used OPA disinfectant go once the clinic has finished with it?
It stays in its container. It is very toxic to aquatic life with long lasting effects, so a drain is never a route. Keep used and unused liquid in its container, labelled as waste, and arrange specialist collection.
Why are there grey-black marks round our OPA bottle?
OPA stains skin, clothing and surfaces grey-black, so the marks show where liquid has escaped. Stand the bottle in a tray, wear gloves and eye protection, and tell the collector the container has leaked.
Is a 0.55% solution as hazardous as the pure substance?
Possibly not, but we do not say it is safe. The classification belongs to the substance, and a ready-to-use product may be less hazardous. Use the supplier label to describe it and treat it as hazardous waste.
Does an opened bottle need to be used within a set time?
We do not set a shelf life. Follow the product label and your infection control procedure, date the bottle when opened, and declare it as waste if it is stained, leaking or past the date your procedure allows.