USPS Packaging Instruction 3B

Combustible Liquids

A combustible liquid having a flashpoint of 140° F (60° C) but no more than 200° F (93° C) is mailable if it qualifies as a Limited Quantity material in the Postal Service for air or surface transportation and meets all applicable requirements in 343. A flammable liquid having a flashpoint of at least 100° F (38° C) but not more than 140° F (60° C) may be reclassed as a combustible liquid within the limits of 49 CFR 173.120(b).

Proper Shipping Name

ID Number

Mailability

Required Packaging

Separate packaging requirements apply, depending on the flashpoint of the combustible liquid.

For flashpoint of at least 100º F (38º C) but not more than 140º F (60º C):
General
Primary Receptacle
Absorbent and Cushioning Material
Secondary Packaging
Outer Packaging
Marking

Labels and markings must be placed on the address side of the mailpiece unless specified differently in 221.1 and 325.1.

For flashpoint above 140º F (60º C) but not more than 200º F (93º C):
General
Primary Receptacle
Absorbent and Cushioning Material
Secondary Packaging
Outer Packaging
Marking

The following labels and text markings must be placed on the address side of the mailpiece unless specified in 221.1 and 325.1.

Documentation
For flashpoint above 200º F (93º C):
General
Primary Receptacle
Absorbent and Cushioning Material
Outer Packaging
Marking