Helium (CAS 7440-59-7): storage and disposal

Check whether the cylinder is hired or bought outright. A label naming a gas company usually means it goes back to them, whereas a small balloon kit canister bought for an open day may have no owner to return to at all. That check saves trouble later. Either way, keep it upright and secured, in a stand or strapped to something fixed, well clear of radiators, stage lighting and direct sun. Schools often leave a cylinder in a drama cupboard or a corner of the hall after an event, unchained and forgotten, so add it to the record with its location and secure it where it stands. University holders of liquid helium should treat those vessels separately. Do not puncture or vent a cylinder to finish it off.

Dents and scuffs on a small canister are what a technician will see first, because these often get carried around for events and thrown in cupboards. Helium itself shows nothing with age, so there is no chemical sign to find and the gas stays as it was. The steel and valve are where the changes appear. Look for rust at the base, a bent valve, a missing guard or a label too worn to read. Balloon kit nozzles left on a canister can be knocked and start a slow leak, and helium escapes readily, so a cylinder may be emptier than its last use suggests. Even so, treat one that seems empty as a pressure container, since looks prove nothing about its contents.

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.

Pressure containers cannot be grouped into a lab pack, whichever gas they hold, so helium is dealt with item by item and not through packing. A hired cylinder goes back to its supplier. Single use canisters and any cylinder with no traceable owner call for a manual enquiry, because this site does not quote for them online. Give the number, size, any label wording and where each stands, and a photograph helps. A store assessment is recommended if a department has built up several. Keep each one upright and secured while you wait for advice. Do not vent, puncture or crush a canister, even when it seems to be empty, and do not put one in a general waste bin or a skip.

Usually held as: cylinder.

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.