# Polychlorinated biphenyls, solid — Postal shipping restrictions by item category For Polychlorinated biphenyls, solid, carrier is USPS; restriction type is restricted; scope is domestic mail: surface only (air prohibited); conditions is Hazard class 9, UN3432, packing group II; domestic mail air: Prohibited; domestic mail surface: 9C, recorded from its source on 2026-08-10. - **Item category:** Polychlorinated biphenyls, 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: surface only (air prohibited) _(our reading, not quoted from the source)_ - **Conditions:** Hazard class 9, UN3432, packing group II; domestic mail air: Prohibited; domestic mail surface: 9C _(verified: appears in the quote below)_ ## What the source says > Polychlorinated biphenyls, solid 9 UN3432 II Prohibited 9C ## 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/).