- Air Transportation. When eligibility for air transportation is sought, mailable hazardous materials eligible for air transportation per subchapter 34 must be sent as Priority Mail Express or Priority Mail. Mailers must prepare mailpieces to meet all requirements that apply to air transportation. Mailpieces must be properly packaged and labeled within DMM requirements and the operator variations of the air carrier. When required, a shipper’s declaration for dangerous goods must be affixed to the outside of the mailpiece.
Note: Mailable hazardous materials that are prohibited from air transportation may not be sent as Priority Mail Express or Priority Mail.
- Surface Transportation. All hazardous materials eligible to be sent as Parcel Select Lightweight or USPS Ground Advantage must be prepared under the requirements that apply to surface transportation. A mailpiece containing mailable hazardous materials utilizing Parcel Select Lightweight or USPS Ground Advantage must not, under any circumstance, be transported on air transportation, except for items in 327.2g.
All mailable hazardous materials sent as Priority Mail Express or Priority Mail must meet the requirements for air transportation. The following types of hazardous materials are always prohibited on air transportation regardless of class of mail:
- Anything susceptible to damage or that can become harmful because of changes in temperature or atmospheric pressures unless protected against the effects of such changes.
- Magnetic material that has a field strength sufficient to cause a compass deviation at a distance of 7 feet or more from any point on the outer packaging.
- Flammable materials (gases, liquids, and solids).
- Radioactive materials.
- UN3090 lithium metal batteries (including lithium alloy batteries) and UN3480 lithium-ion batteries (including lithium polymer batteries).
- Used, damaged, or defective electronic devices (excluding devices that are new in original packaging, and manufacturer-certified new or refurbished devices) containing or packaged with lithium batteries (see 349.12e). For those ZIP Codes that are air transportation only due to the absence of ground transportation, a multimodal-transportation solution may be used to transport used, damaged, or defective electronic devices containing or packed with lithium batteries. See Appendix F for a list of 5-digit ZIP Codes where this exception applies.
- Materials excluded from air shipment by DOT regulations (49 CFR 100-185) or of the applicable state (country) or air carrier operator variations.