Skip to content

Chemical collection and stock control for UK schools, universities and hospitals

Carbon monoxide (CAS 630-08-0): storage and disposal

Carbon monoxide is held in university labs in cylinders, either as the pure gas or as a mixture bought to calibrate instruments. It is extremely flammable, toxic if inhaled, may damage the unborn child and causes organ damage with repeated exposure. It has no colour or smell, so a leak gives no warning. The label, and who owns the cylinder, decide how it is handled.

CAS number
630-08-0
Form
Gas
Storage class
Flammable
Signal word
Danger
Usual EWC code
16 05 04*
  • Flammable pictogramFlammable
  • Gas under pressure pictogramGas under pressure
  • Acute toxicity pictogramAcute toxicity
  • Serious health hazard pictogramSerious health hazard

This chemical is a manual enquiry

This is held as a compressed gas. Cylinders are usually returned to the supplier or handled separately, and they do not go into a laboratory pack.

Held as a compressed or liquefied gas in a pressure container.

It cannot be priced through a form. Please do not open or move it. Call us or send an enquiry and we will talk through the safe next step, which is often a store assessment.

What to do this week

  1. Leave it where it is. If it looks old, crystalline or damaged, do not open or move it and keep people away from the shelf.
  2. Write down the label wording, the rough age and where it is stored, from a safe distance.
  3. Send us those details, and a photo if you can take one without touching it.

Safe storage in a school or lab

Ask first whether the store has a working carbon monoxide alarm, because no one will see or smell a leak without one. Ventilation is the other half of the answer: a closed cupboard or a small windowless room lets the gas build up unnoticed. Stand the cylinder upright and secured, away from heat and ignition sources, and apart from oxidisers, which can make a fire far more intense. Fumes from acids and corrosive stock attack valves and seals, so those stores are unsuitable too. Tell anyone pregnant that it is there, as it may damage the unborn child. Nobody should puncture the cylinder or vent it, even when it seems nearly finished.

How to tell it has deteriorated

The first thing on the shelf is usually the label, and on this gas it matters more than the appearance. It tells you whether the cylinder is pure gas or a low level instrument mixture. Carbon monoxide gives few visible signs of age, and it has no colour or smell to give a leak away, so a cylinder can look perfect while leaking. Beyond that, look for rust, a bent valve, a missing cap or a test stamp long out of date. A carbon monoxide alarm can provide warning of a leak that cannot be identified by sight or smell. If one sounds, leave at once, keep people out and call the fire service. Do not go back to look at the valve.

How it must be disposed of

This does not go through our standard collection route. It is arranged by manual enquiry, and never goes down the drain or into general waste.

Write down the shoulder label wording, whether it says pure gas or a mixture, the supplier name, the cylinder size and any test stamp, then photograph them if you can do so without moving anything. Those details are what a supplier needs, and most cylinders go back to theirs. If the owner cannot be traced, the same details go into a manual enquiry, along with where it is kept. Carbon monoxide is not quoted online, and a store assessment is recommended. A lab pack is not available for it, because pressure containers cannot go in one. Keep it upright and secured where it stands. It must not be vented or left out as scrap metal.

Waste codes and transport details for Carbon monoxide
EWC code, laboratory chemicals16 05 04*
Hazardous wasteYes

Gases in pressure containers are assessed by manual enquiry, usually with return to the cylinder owner.

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

  • OxidiserOxidisers can ignite flammable materials or make a fire far more intense.
  • AcidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • CorrosiveA leak of corrosive stock can break down flammable containers and feed a fire.

Named chemicals to keep apart

  • Acetic acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Calcium hypochloriteOxidisers can ignite flammable materials or make a fire far more intense.
  • Hydrochloric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Hydrogen peroxideOxidisers can ignite flammable materials or make a fire far more intense.
  • Nitric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Potassium nitrateOxidisers can ignite flammable materials or make a fire far more intense.
  • Potassium permanganateOxidisers can ignite flammable materials or make a fire far more intense.
  • Sulfuric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
Show 2 more
  • Thionyl chlorideA leak of corrosive stock can break down flammable containers and feed a fire.
  • Zinc chlorideA leak of corrosive stock can break down flammable containers and feed a fire.

Common quantities we collect

Usually held as: cylinder.

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

  • H220 Extremely flammable gas.
  • H280 Contains gas under pressure; may explode if heated.
  • H331 Toxic if inhaled.
  • H360D May damage the unborn child.
  • H372 Causes damage to organs through prolonged or repeated exposure.
Precautionary statements
  • P203 Obtain, read and follow all safety instructions before use.
  • P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P222 Do not allow contact with air.
  • 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.
  • 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.
  • 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).
  • P377 Leaking gas fire: Do not extinguish, unless leak can be stopped safely.
  • P381 In case of leakage, eliminate all ignition sources.
  • P403 Store in a well-ventilated place.
  • 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.
  • P410+P403 Protect from sunlight. Store in a well-ventilated place.

Substance as classified, dilutions may differ.

Questions

Would an ordinary smoke alarm warn us about a carbon monoxide leak?

No. A smoke alarm responds to particles from a fire, and it will not detect this gas. A store holding it needs carbon monoxide detection equipment suitable for the workplace risks, selected, positioned and maintained according to the site's risk assessment, with a clear procedure for evacuation when an alarm sounds.

Our cylinder is a calibration mixture of carbon monoxide in nitrogen. Does the same route apply?

Yes, the first steps are the same. It is still a pressure container, so a lab pack is ruled out, and the supplier is the usual place to return it. Quote the exact label wording, because the mixture's own classification may differ from the pure gas described here.

Should pregnant staff be working in a lab that uses this gas?

That is a question for your risk assessment and occupational health adviser, as it may damage the unborn child. Tell staff the gas is in use so that they can raise it early. Good alarms, ventilation and a short list of people with access all feed into the decision.

If the cylinder is very old, has the gas become less dangerous?

Assume it has not. Nothing you can see shows what remains inside, and an old cylinder should be regarded as still extremely flammable and under pressure. Age mostly raises questions about the valve and the test date, which are matters for the supplier to judge.

Guidance only. Check your own risk assessment and your supplier's safety data sheet.

Hazard data source: PubChem GHS Classification, retrieved 31 Oct 2026. Formula CO. EC number 211-128-3.

Manual enquiry Add to register
Search the chemical database