# Oxygen generator, chemical (including when contained in associated equipment, e.g., passenger service units (PSUs), portable breathing equipment (PBE), etc.) — Postal shipping restrictions by item category

For Oxygen generator, chemical (including when contained in associated equipment, e.g., passenger service units (PSUs), portable breathing equipment (PBE), etc.), carrier is USPS; restriction type is prohibited; scope is domestic mail (air and surface); conditions is Hazard class 5.1, UN3356, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited, recorded from its source on 2026-08-10.

- **Item category:** Oxygen generator, chemical (including when contained in associated equipment, e.g., passenger service units (PSUs), portable breathing equipment (PBE), etc.) _(verified: appears in the quote below)_
- **Carrier:** USPS _(our reading, not quoted from the source)_
- **Restriction type:** prohibited _(our reading, not quoted from the source)_
- **Scope:** domestic mail (air and surface) _(our reading, not quoted from the source)_
- **Conditions:** Hazard class 5.1, UN3356, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited _(verified: appears in the quote below)_

## What the source says

> Oxygen generator, chemical (including when contained in associated equipment, e.g., passenger service units (PSUs), portable breathing equipment (PBE), etc.) 5.1 UN3356 II Prohibited Prohibited

## 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/).