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Home > Guides > Shipping with dry ice
You can, but it is not a normal parcel: dry ice is solid carbon dioxide, and as it sublimates it releases gas. On aircraft it is regulated as UN1845 Class 9 dangerous goods; on the ground it is simpler but must still be packed so the gas can escape. Never seal dry ice in an airtight container: pressure buildup can burst the package.
LetterAgent can't help with dry ice shipments: our labels are Canada-only Xpresspost with a five-kilogram limit, and dry ice is a dangerous good that carriers handle under special rules. This guide covers the general method.
Dry ice does not melt; it sublimates straight into carbon dioxide gas, expanding enormously as it does. A sealed cooler or a heat-sealed bag becomes a pressure vessel. Vented packaging, an insulated cooler with the lid cracked or vent holes, inside a fibreboard box with vent slots, lets the gas escape while the insulation keeps the contents cold. Mark the outside of the box with "Dry Ice" and the net weight of the dry ice: that marking is a regulatory requirement on air shipments and good practice everywhere else.
| Mode | How dry ice is treated | What you must do |
|---|---|---|
| Ground | Still a regulated material, but far fewer restrictions | Vented insulated packaging, marked, kept upright |
| Air | UN1845, Class 9 dangerous goods; per-package quantity caps apply | Declare it, mark net weight, book through a carrier's dangerous-goods process |
| Passenger baggage | Generally allowed in small amounts with airline approval | Vented packaging, declared at check-in |
The standard build is three layers: the product in a sealed inner bag (so condensation and CO2 do not touch the food or item directly), dry ice in an insulated cooler with venting, and the cooler inside a sturdy outer box with vent slots. Put the dry ice on top of the product, not underneath: cold gas sinks, so top placement cools downward and evenly. Do not mix regular ice and dry ice in a sealed space, and keep the package upright through handling: tape "this side up" arrows and a "do not stack" note if the route allows it.
Two safety details people miss. First, CO2 is an asphyxiant in enclosed spaces: never open a dry-ice shipment in a small sealed room, and drivers moving many dry-ice parcels ventilate their vehicles for a reason. Second, dry ice burns skin on contact: wear gloves when handling it, and make sure the recipient knows what is inside before they open the box. A plain note on the inside flap, "Dry ice inside: handle with gloves," prevents the most common injury.
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