# Flammable solids, toxic, organic, n.o.s. · USPS · III — Mailing and air-carriage restrictions by item category

For Flammable solids, toxic, organic, n.o.s. · USPS · III, item category is Flammable solids, toxic, organic, n.o.s; carrier is USPS; dot packing group is III; restriction type is restricted; scope is domestic mail: surface only (air prohibited), recorded from its source on 2026-08-29.

- **Item category:** Flammable solids, toxic, organic, n.o.s. _(verified: appears in the quote below)_
- **Carrier:** USPS _(our reading, not quoted from the source)_
- **DOT packing group:** III _(verified: appears in the quote below)_
- **Restriction type:** restricted _(our reading, not quoted from the source)_
- **Scope:** domestic mail: surface only (air prohibited) _(our reading, not quoted from the source)_
- **Conditions:** Hazard class 4.1, UN2926, packing group III; domestic mail air: Prohibited; domestic mail surface: 4A

## What the source says

> Flammable solids, toxic, organic, n.o.s. 4.1 UN2926 III Prohibited 4A

## Source

- https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf

Last verified: 2026-08-29. Review by: 2027-08-29.
Part of [Mailing and air-carriage restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).