# Flammable solids, toxic, organic, n.o.s. · USPS · II — Mailing and air-carriage restrictions by item category For Flammable solids, toxic, organic, n.o.s. · USPS · II, item category is Flammable solids, toxic, organic, n.o.s; carrier is USPS; dot packing group is II; restriction type is prohibited; scope is domestic mail (air and surface), 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:** II _(verified: appears in the quote below)_ - **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 4.1, UN2926, packing group II; domestic mail air: Prohibited; domestic mail surface: Prohibited ## What the source says > Flammable solids, toxic, organic, n.o.s. 4.1 UN2926 II Prohibited Prohibited ## 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/).