# Trimethylamine, aqueous solutions with not more than 50 percent trimethylamine by mass · USPS · I, II — Mailing and air-carriage restrictions by item category For Trimethylamine, aqueous solutions with not more than 50 percent trimethylamine by mass · USPS · I, II, item category is Trimethylamine, aqueous solutions with not more than 50 percent trimethylamine by mass; carrier is USPS; dot packing group is I, II; restriction type is prohibited; scope is domestic mail (air and surface), recorded from its source on 2026-08-29. - **Item category:** Trimethylamine, aqueous solutions with not more than 50 percent trimethylamine by mass _(verified: appears in the quote below)_ - **Carrier:** USPS _(our reading, not quoted from the source)_ - **DOT packing group:** I, 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 3, UN1297, packing group I, II; domestic mail air: Prohibited; domestic mail surface: Prohibited ## What the source says > Trimethylamine, aqueous solutions with not more than 50 percent trimethylamine by mass 3 UN1297 I, 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/).