Iodomethane (CAS 74-88-4): storage and disposal
Iodomethane, commonly called methyl iodide, is kept in college and university stores, usually in a small glass bottle in a locked cabinet. It is toxic if swallowed and if inhaled, harmful in contact with skin, irritating to skin, eyes and airways, suspected of causing cancer and very toxic to aquatic life. Light is the usual cause of trouble with old bottles, and the inhalation hazard decides who opens them.
- CAS number
- 74-88-4
- Form
- Liquid
- Storage class
- Toxic
- Signal word
- Danger
- Usual EWC code, laboratory stock
- 16 05 06*
Acute toxicity
Serious health hazard
Hazardous to the environment
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 or university prep room, iodomethane belongs in the locked toxics cabinet with a stock record, away from food and drink areas and from acids and oxidisers. Keep the bottle in its dark glass or in a closed box, because light is what damages it. Staff should not be opening it at an open bench, since the vapour is toxic if inhaled, so any handling belongs in a fume cupboard. Only people named on the stock record should hold the key. Check at each stock review that the bottle is upright, capped and still labelled.
How to tell it has deteriorated
One well known sign stands out: colour. A clear liquid turns yellow and then brown as light frees iodine, and an old bottle may stain its own cap, neck and the shelf beneath with brown. A bottle that has browned should not be opened to look. Check for a label gone brown too, a dried cap liner, a lowered level and any smell in the cabinet. Because the vapour is toxic if inhaled, a bottle with a failing seal or a smell in the room should be reported rather than investigated.
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 We do not publish a drain or general waste route for any chemical.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.
What must not happen to iodomethane is any attempt to treat it, pour it away, evaporate it or move it between bottles to clean it up. Browned stock is still described as iodomethane and goes by specialist collection, grouped with compatible halogenated organics. Give the size, remaining level and the colour, and say whether the cap is stained. The usual list code is 16 05 06* for packed stock, and a loose discarded organic chemical not sent in a pack can use 16 05 08*. Keep it in the locked cabinet until the collector arrives.
| Usual EWC code, laboratory stock | 16 05 06* |
|---|---|
| Discarded organic chemical, not a laboratory pack | 16 05 08* |
| 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.
- 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
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
- H301 Toxic if swallowed.
- H312 Harmful in contact with skin.
- H315 Causes skin irritation.
- H319 Causes serious eye irritation.
- H331 Toxic if inhaled.
- H335 May cause respiratory irritation.
- H351 Suspected of causing cancer.
- H400 Very toxic to aquatic life.
- H411 Toxic to aquatic life with long lasting effects.
Precautionary statements
- P203 Obtain, read and follow all safety instructions before use.
- P261 Avoid breathing 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.
- 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.
- P317 Get medical help.
- 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.
- P332+P317 If skin irritation occurs: Get medical help.
- P362+P364 Take off 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.
- P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- P233 Keep container tightly closed.
- P240 Ground and bond container and receiving equipment.
- P241 Use explosion-proof electrical, ventilating and lighting equipment.
- P242 Use non-sparking tools.
- P243 Take action to prevent static discharges.
- P260 Do not breathe dust, fume, gas, mist, vapours or spray.
- P264+P265 Wash hands and exposed skin thoroughly after handling. Do not touch eyes.
- P272 Contaminated work clothing should not be allowed out of the workplace.
- P273 Avoid release to the environment.
- P284 In case of inadequate ventilation wear respiratory protection.
- P303+P361+P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
- P305+P351+P338 IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing.
- P333+P317 If skin irritation or rash occurs: Get medical help.
- P337+P317 If eye irritation persists: Get medical help.
- P342+P316 If experiencing respiratory symptoms: Get emergency medical help immediately.
- P370+P378 In case of fire: Use suitable extinguishing media to extinguish.
- P391 Collect spillage.
- P403 Store in a well-ventilated place.
- P403+P235 Store in a well-ventilated place. Keep cool.
Substance as classified, dilutions may differ.
Questions
Why has our iodomethane turned brown?
Light frees iodine from the liquid over time, so it moves from clear to yellow and then brown, and may stain the cap and shelf. Keep it capped in the dark, locked cabinet, record the colour and list it for collection.
Can we open a browned bottle to check what is left?
No. It is toxic if inhaled, so any opening belongs in a fume cupboard and is best avoided on old stock. Check the level through the glass and tell the collector the remaining quantity.
Do we need a locked cabinet for iodomethane?
Yes, it is toxic if swallowed and if inhaled, so keep it in a locked cabinet with a stock record, away from food and drink areas and from acids and oxidisers.