# Lead phosphite, dibasic · USPS · III — Mailing and air-carriage restrictions by item category For Lead phosphite, dibasic · USPS · III, item category is Lead phosphite, dibasic; 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:** Lead phosphite, dibasic _(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, UN2989, packing group III; domestic mail air: Prohibited; domestic mail surface: 4A ## What the source says > Lead phosphite, dibasic 4.1 UN2989 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/).