Postal Explorer > Publication 52 - Hazardous, Restricted, and Perishable Mail > Appendix C USPS Packaging Instructions for Mailable Hazardous Materials > USPS Packaging Instruction 4A

USPS Packaging Instruction 4A

Flammable Solids

A flammable solid that can qualify as an ORM-D material is permitted in the domestic mail via surface transportation only, provided all applicable requirements in 344 are met.

Proper Shipping Name

• Consumer Commodity.

ID Number

• Various (see Appendix A).

Mailability

• International Mail: Prohibited.

• Domestic Mail: Permitted only via surface transportation sent as Standard Mail or Parcel Post.

Required Packaging

Primary Receptacle

• The primary receptacle must have a secure seal and together with its contents must not exceed a weight of 1 pound.

• Multiple primary receptacles are permitted.

Cushioning Material

• Sufficient cushioning material must be used to absorb shock and the primary receptacle from breakage.

Outer Packaging

• Strong outer packaging that is capable of firmly and securely holding the primary receptacle and cushioning material is required.

• Each mailpiece must not exceed a total weight of 25 pounds.

Marking

• Each mailpiece must be clearly marked on the address side with "Surface Only" or "Surface Mail Only" and "Consumer Commodity ORM-D."

• A complete return address and delivery address must be used.