# Flammable liquids with flashpoint above 20 F — domestic surface — Postal shipping restrictions by item category

For Flammable liquids with flashpoint above 20 F, item category is Flammable liquids with flashpoint above 20 F — domestic surface; carrier is USPS; restriction type is restricted; scope is domestic mail via surface transportation only; conditions is Mailable if qualifies as Limited Quantity surface material and meets criteria; must follow Packaging Instruction 3A, recorded from its source on 2026-08-04.

- **Item category:** Flammable liquids with flashpoint above 20 F — domestic surface _(unconfirmed — we could not tie this to 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 via surface transportation only _(our reading, not quoted from the source)_
- **Conditions:** Mailable if qualifies as Limited Quantity surface material and meets criteria; must follow Packaging Instruction 3A _(unconfirmed — we could not tie this to the quote below)_

## What the source says

> Other flammable liquids may be mailed if they qualify as a Limited Quantity surface material and meet the criteria in Exhibit 343.21

## 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/).