Class 2 gases and compressed-gas confusion

Blood drive truck dry ice 2.2 un1845 matching testing differences online free flash app

Watch the classification. Dry ice (solid carbon dioxide, UN 1845) is regulated as Class 9 miscellaneous, not as a 2.2 gas. Carbon dioxide as a compressed gas (UN 1013) is the green Division 2.2 non-flammable gas. So UN 1845 dry ice and gaseous CO2 are different entries, and pairing dry ice with 2.2 is the common mix-up.

Blood drive truck dry ice 2.2 un1845 matching testing differences online free flash app · CDL Placards Hazmat placard practice

Dry ice is Class 9, not 2.2

Dry ice is frozen carbon dioxide, and as a solid it is assigned UN 1845 and regulated as Class 9 miscellaneous. The hazard is that it sublimates, turning back into gas, which can displace oxygen in an enclosed space and build pressure. That asphyxiation-and-pressure profile is why it sits in the catch-all Class 9 rather than with the compressed gases.

Gaseous CO2 is the 2.2 one

Carbon dioxide as a compressed or refrigerated gas is a different entry, and that one is a green Division 2.2 non-flammable gas. So the 2.2 label in the question belongs to gaseous carbon dioxide, not to dry ice. Same chemical, different physical form, different classification and UN number.

Dry ice versus CO2 gas

The pairing to get right:

Dry iceCarbon dioxide gas
What it isSolid CO2Compressed CO2 gas
UN numberUN 1845UN 1013
ClassClass 9 (miscellaneous)Division 2.2 (non-flammable gas)
Main hazardSublimation, oxygen displacementPressurized non-flammable gas

Dry ice (UN 1845) is Class 9; CO2 gas (UN 1013) is 2.2. Confirm in your official manual.

Why blood and medical loads use it

Dry ice is common on medical, lab, and blood-drive shipments because it keeps contents very cold. That practical use is why drivers run into it, and why the dry-ice-versus-CO2 confusion comes up. The cooling job does not change the classification: as a solid it is UN 1845, Class 9.

Exceptions and how to verify

There are exceptions and special provisions for dry ice, including for certain small quantities and uses, so not every dry-ice shipment is handled the same way. Because those provisions are detailed and can change, confirm the current requirements for your specific shipment in the regulations and your official manual rather than assuming.

Frequently asked questions

Is dry ice 2.2 or Class 9?
Dry ice (solid CO2, UN 1845) is Class 9 miscellaneous. The 2.2 non-flammable gas entry is carbon dioxide as a gas (UN 1013). They are separate entries. Confirm in your official manual.
What is UN 1845?
The identification number for dry ice (solid carbon dioxide), regulated as Class 9. Its hazard is sublimation, which displaces oxygen and builds pressure in enclosed spaces.
Why is dry ice not a non-flammable gas placard?
Because as a solid its hazard is sublimation and oxygen displacement, which fits Class 9. The non-flammable gas (2.2) entry is for carbon dioxide in gas form (UN 1013).

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