# Flammable liquids (Hazard Class 3) — domestic air — Postal shipping restrictions by item category

For Flammable liquids (Hazard Class 3), item category is Flammable liquids (Hazard Class 3) — domestic air; carrier is USPS; restriction type is prohibited; scope is domestic mail via air transportation; conditions is All flammable liquids are prohibited from domestic air mail, recorded from its source on 2026-08-04.

- **Item category:** Flammable liquids (Hazard Class 3) — domestic air _(unconfirmed — we could not tie this to 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 via air transportation _(our reading, not quoted from the source)_
- **Conditions:** All flammable liquids are prohibited from domestic air mail

## What the source says

> Domestic Mail via Air Transportation: Flammable liquids are prohibited.

## Source

- https://pe.usps.com/text/pub52/pub52c3_022.htm

Last verified: 2026-08-04. Review by: 2027-08-04.
Part of [Postal shipping restrictions by item category](https://referencesource.org/shipping-restrictions-by-class/).