# Toxic by inhalation liquid, water- reactive, flammable, n.o.s. with an LC50 lower than or equal to 200 ml/ m3 and saturated vapor concentration greater than or equal to 500 LC50- · USPS — Mailing and air-carriage restrictions by item category

For Toxic by inhalation liquid, water- reactive, flammable, n.o.s. with an LC50 lower than or equal to 200 ml/ m3 and saturated vapor concentration greater than or equal to 500 LC50- · USPS, item category is Toxic by inhalation liquid, water- reactive, flammable, n.o.s. with an LC50 lower than or equal to 200 ml/ m3 and saturated vapor concentration greater than or equal to 500 LC50-; carrier is USPS; restriction type is prohibited; scope is domestic mail (air and surface); conditions is Hazard class 6.1, UN3490, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited, recorded from its source on 2026-08-30.

- **Item category:** Toxic by inhalation liquid, water- reactive, flammable, n.o.s. with an LC50 lower than or equal to 200 ml/ m3 and saturated vapor concentration greater than or equal to 500 LC50- _(verified: appears in the quote below)_
- **Carrier:** USPS _(our reading, not quoted from the source)_
- **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 6.1, UN3490, packing group I; domestic mail air: Prohibited; domestic mail surface: Prohibited

## What the source says

> Toxic by inhalation liquid, water- reactive, flammable, n.o.s. with an LC50 lower than or equal to 200 ml/ m3 and saturated vapor concentration greater than or equal to 500 LC50- 6.1 UN3490 I Prohibited Prohibited

## 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/).