Carbon dioxide (CAS 124-38-9): storage and disposal

A tall supplier cylinder and a box of small sparklet bulbs are the two forms found, and they need quite different attention. The cylinder stands upright and is chained or held in a stand, as it would be if feeding a pathology incubator, well clear of heaters and direct sun. Bulbs are more easily lost: loose in a drawer in the prep room, in a box beside the old demonstration kit, or left on a warm windowsill, where heat can raise the pressure inside. Keep them in their box, in a cool and labelled place, and keep the box dry so the thin steel does not rust. Never pierce a bulb or a cylinder valve to get rid of the contents, however few remain.

Rust on a small steel bulb is usually what a technician will see first, particularly in an old box kept somewhere damp. Rust weakens thin metal, and a badly rusted bulb should be left alone and recorded. Carbon dioxide itself shows nothing with age, so the gas is not the issue. A bulb with a pierced seal has been used and an unpierced one has not, although looks alone do not prove it is empty. Cylinders show their age through a worn supplier label, dents, damage to the valve or base rust. A hiss from a fitting suggests a leak, which can build up in a closed room, so leave the room, keep others out and call the owner or your site contact. Frost on a valve may also mean a leak of the cold gas.

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.

It leaves by returning to whoever owns it, in the case of most cylinders, as these normally stay the supplier's property. Bulbs are less clear, and this site does not quote for either form online, since pressure containers are kept out of lab packs. Send a manual enquiry listing how many bulbs there are, whether any are rusted, and for cylinders the size, label wording and location. A store assessment is recommended where a large or mixed quantity has built up. Keep the items in place, upright and away from heat, until advice arrives. Do not puncture or vent anything to make it easier. Never put any of it in a general waste bin or skip, whether full or apparently empty.

Usually held as: cylinder, sparklet bulbs.

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.