Dry Ice Shipping Rules Explained (UN1845, Class 9)

Dry ice ships under the proper shipping name "Carbon Dioxide, Solid," UN numberUN1845, classified as Class 9 miscellaneous dangerous goods by both DOT and IATA — and while it's a common refrigerant, shipping it incorrectly is a genuine compliance risk, not a formality.

Quantity Limits

The maximum net quantity of dry ice allowed per package is 200 kg under the general rule, though individual carriers frequently impose lower package limits — some UPS shipping tables cap dry ice at 68 kg per package regardless of the regulatory maximum (HazmatUniversity). Always check the specific carrier's limit in addition to the regulatory ceiling.

The Small-Quantity Exception

Dry ice used as a refrigerant in quantities not exceeding 2.5 kg per package is excepted from most other requirements — provided the package is marked with "Carbon Dioxide, Solid" or "Dry Ice," the name of the contents being cooled, and the net weight of the dry ice itself (eCFR §173.217). This exception is why many small cold-chain shipments move without a full DG paper trail.

Mode-by-Mode Regulation

Dry ice's regulatory status changes depending on how it moves:

• Highway (domestic U.S.): Not fully regulated, provided minimum packaging requirements — venting capability, correct marking — are met.
• Air and vessel: Fully regulated regardless of quantity, requiring complete DG documentation, labeling, and packaging compliance (HazmatUniversity).

A shipper who treats dry ice as a low-regulation ground item and then ships the same package by air without adjusting compliance is the most common way this substance trips up otherwise careful teams.

Packaging Requirements

Dry ice sublimates directly into carbon dioxide gas, so packaging has one requirement that overrides most others: it must be designed and constructed to release CO2 gas and prevent pressure buildup (eCFR §173.217). A fully sealed, non-venting container isn't just noncompliant — it's a rupture risk.

Labeling and Documentation Requirements

For fully regulated shipments (air and vessel), the outermost container must display:

• A Class 9 hazard label
• The UN number, UN1845
• The net weight of dry ice in kilograms

Shipping papers must include full shipper and consignee information, the proper shipping name, the UN number, and the total quantity of dry ice in the shipment (HazmatUniversity).

Why Dry Ice Trips Up Otherwise Compliant Shippers

Dry ice feels mundane — it's a refrigerant, not an explosive or a corrosive — which is exactly why shippers underestimate it. The venting requirement is easy to miss when packaging is chosen primarily for insulation performance rather than gas release, and the exception threshold (2.5 kg) is a specific number that's easy to exceed without noticing once a shipment scales up.

How Inspection Software Helps

DG inspection software that flags dry ice quantities against both the 2.5 kg exception threshold and carrier-specific package limits — and confirms packaging is marked as venting-capable — catches the two most common dry ice compliance gaps before a shipment reaches the carrier.

The Bottom Line

Dry ice (UN1845) is Class 9, capped at 200 kg per package under the general rule (often lower per carrier), exempt from most requirements below 2.5 kg per package, and fully regulated the moment it moves by air or vessel. Venting-capable packaging isn't optional — it's the single requirement that exists specifically because of how dry ice behaves in transit.

Sources:

• Understanding the Regulations Around Shipping Dry Ice — HazmatUniversity
• eCFR 49 CFR 173.217 — Carbon dioxide, solid (dry ice)