Mailing Standards for Hazardous Materials

Many types of consumer goods are considered hazardous materials (HAZMAT) when mailed. Some of the most common examples include the following:

n Toys and electronics containing lithium batteries,

n Perfume or hairspray,

n Shaving gel, and

n Some cleaning agents.

For up-to-date mailing standards for hazardous materials, visit Postal Explorer® ( to access Publication 52, Hazardous, Restricted, and Perishable Mail. Publication 52 provides important information mailers need to determine which of these items they can mail and how they must package them to keep the mail safe. As a critical source of information for Postal Service acceptance personnel, Publication 52 also features:

n Fly-out menus,

n Cross-reference links, and

n An extensive subject index.

New Mailing Standards for Lithium Batteries

Currently, the most common hazardous material in the mail is lithium batteries. Effective August 17, 2017, the Postal Service revised various sections of Publication 52 to provide new mailing standards for mailpieces containing lithium batteries. The new changes become mandatory January 1, 2018; however, mailers may use the new standards immediately. You can find a complete list of these changes in Postal Bulletin 22474 (


Not all batteries are considered hazardous materials. Some types of non-hazardous batteries include single-use alkaline and “dry cell” batteries. Check the battery and the package to determine if your batteries contain lithium.

Lithium batteries come in many shapes and sizes, and pose different levels of danger during transportation. Mailers must provide basic information about their batteries to determine if they are mailable. Manufacturers usually print this information on the packaging or directly onto the battery. In other cases, you may find this information online by searching for the battery specification or safety data sheet.To determine mailability for lithium batteries, look for the following information:

1. Is the lithium battery rechargeable?

a. If the answer is yes, it is a lithium-ion (polymer) battery and you must:

(1) Refer to UN3480 for lithium-ion batteries packaged without equipment.

(2) Refer to UN3481 for lithium-ion batteries packaged with or in equipment.

b. If the answer is no, it is a lithium metal (alloy) battery and you must:

(1) Refer to UN3090 for lithium metal batteries packaged without equipment.

(2) Refer to UN3091 for lithium metal batteries packaged with or in equipment.

2. How is the battery packaged?

a. Separate — the battery is shipped by itself.

b. With equipment — the battery is packaged with the equipment it is intended to operate, but not installed.

c. In equipment — the battery is installed in the equipment it is intended to operate.

3. What is the battery type and size?

a. Button cell or “very small” — maximum 0.3 grams of lithium or 2.7 Wh capacity.

b. Cell (single cell battery) — maximum 1 gram of lithium or 20 Wh capacity (at 3.7 volts or less).

c. Battery (multi-cell battery) — maximum 2 grams of lithium or 100 Wh capacity.

Once you can answer these three questions, use the information in Publication 52, Appendix C, Packaging Instruction 9D (domestic) or Packaging Instruction 9E (international and APO/FPO/DPO) to determine the following:

n Quantity limits,

n Packaging requirements,

n Marking requirements, and

n Labeling requirements.

Note: The Postal Service prohibits mailing batteries with more than 2 grams of lithium or 100 Wh capacity.

If you need assistance, USPS® HAZMAT specialists are here to help. Please email any questions to