USPS Packaging Instruction 5A

Oxidizing Substances, Organic Peroxides

An oxidizing substance or an organic peroxide that qualifies as a Limited Quantity material within the Postal Service is permitted in the domestic mail for air and surface transportation provided that all applicable requirements in 345 are met.

Proper Shipping Name

• Various (refer to Appendix A).

ID Number

• Various (refer to Appendix A).

Mailability

• International Mail: Prohibited.
• Domestic Mail: Permitted with restrictions via air transportation, or surface transportation.

Required Packaging

Primary Receptacle

• For liquids, the capacity of the primary receptacle must not exceed 1 pint (.0473 liters).
• For solids, the weight of the contents of the primary receptacle must not exceed 1 pound (.0453 kg).
• Multiple primary receptacles are permitted up to a total weight of 25 pounds per mailpiece.

Absorbent and Cushioning Material

• Enough absorbent and cushioning material must surround the primary receptacle to prevent breakage and absorb all potential leakage.

Secondary Packaging

• For liquids only, the cushioning and primary receptacle must be packed in a secondary leak–resistant packaging or material that is securely sealed.

Outer Packaging

• A strong outer packaging that is capable of firmly and securely holding the primary receptacle(s) and cushioning material is required. Refer to 339.4.
• Each mailpiece must not exceed a total weight of 25 pounds.

Marking

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

• For air transportation, mailpieces must bear the DOT Limited Quantity air mark (with the symbol “Y” in the center), an approved DOT Class 5.1 or 5.2 hazardous material warning label, Identification Number and the proper shipping name.
• For surface transportation, the outer packaging must bear an approved DOT Limited Quantity surface mark designating surface transportation, prepared under 343.3(c).
• A complete return and delivery address must be used.

Documentation

• For air transportation, a mailable material must have a properly completed Shipper’s Declaration for Dangerous Goods that is prepared in triplicate affixed to the outside of the mailpiece.
• The shipper’s declaration must be properly completed and signed by the mailer.