# Nitrocresols, solid · USPS — Mailing and air-carriage restrictions by item category For Nitrocresols, solid · USPS, item category is Nitrocresols, solid; carrier is USPS; restriction type is restricted; scope is domestic mail (air and surface); conditions is Hazard class 6.1, UN2446, packing group III; domestic mail air: 6A; domestic mail surface: 6A, recorded from its source on 2026-08-30. - **Item category:** Nitrocresols, solid _(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 6.1, UN2446, packing group III; domestic mail air: 6A; domestic mail surface: 6A ## What the source says > Nitrocresols, solid 6.1 UN2446 III 6A 6A ## Source - https://pe.usps.com/cpim/ftp/pubs/pub52/pub52.pdf Last verified: 2026-08-30. Review by: 2027-08-30. Part of [Mailing and air-carriage restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).