# Carbon dioxide, solid, or Dry ice — Postal shipping restrictions by item category For Carbon dioxide, solid, or Dry ice, carrier is USPS; restriction type is restricted; scope is domestic mail (air and surface); conditions is Hazard class 9, UN1845, packing group III; domestic mail air: 9A; domestic mail surface: 9A, recorded from its source on 2026-08-10. - **Item category:** Carbon dioxide, solid, or Dry ice _(verified: appears in the quote below)_ - **Carrier:** USPS _(our reading, not quoted from the source)_ - **Restriction type:** restricted _(our reading, not quoted from the source)_ - **Scope:** domestic mail (air and surface) _(our reading, not quoted from the source)_ - **Conditions:** Hazard class 9, UN1845, packing group III; domestic mail air: 9A; domestic mail surface: 9A _(verified: appears in the quote below)_ ## What the source says > Carbon dioxide, solid, or Dry ice 9 UN1845 III 9A 9A ## Source - https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf Last verified: 2026-08-10. Review by: 2027-08-10. Part of [Postal shipping restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).