Pricing & Classification DMM Advisory

Message board to keep postal customers informed of changes to mailing standards, services, and prices.

April 24, 2023

Postal Service Implements New Requirements for Using Electronic Indicator for Hazardous Materials

On April 21, 2023, the Postal Service issued its final rule requiring Electronic Indicators when shipping Hazardous Materials (HAZMAT) and Dangerous Goods (DG). The final rule will require use of Service Type Codes (STCs) specific to HAZMAT/DG shipments effective July 9, 2023. The final rule also states that effective January 21, 2024, mailers of HAZMAT/DG must implement the new two-dimensional barcode or Intelligent Mail Matrix Barcode (IMmb) when shipping, in addition to the existing Intelligent Mail Package barcode (IMpb). On November 30, 2022, the Postal Service issued a proposed rule outlining several proposals to improve identification and processing of HAZMAT/DG goods.

In this final rule, the Postal Service revises Publication 52, Hazardous, Restricted, and Perishable Mail (Pub 52) to incorporate new requirements for mailers to use unique STCs and extra service codes (ESCs) within the tracking barcodes and electronic data submission for package shipments containing HAZMAT or DG. This rule standardizes the acceptance and handling of shipments containing HAZMAT/DG by collecting electronic data and will allow the Postal Service to create electronic manifests for the Postal Service’s air carrier suppliers. The following items are clarified in this rule:

  • When shipping HAZMAT internationally, dangerous goods (DG) terminology is used rather than HAZMAT.
  • HAZMAT and DG are not eligible to be mailed in letter or flat-sized mailpieces.
  • These new requirements are in addition to current Pub 52 regulations and do not exempt mailers from complying with existing standards.
  • When shipping to Army Post Office (APO), Fleet Post Office (FPO) or Diplomatic Post Office (DPO) destinations, mailers must follow international DG regulations. This mail is only treated as domestic for pricing purposes.
  • Packages being sent domestically containing new electronic devices, in original unopened packaging or manufacturer certified new or refurbished devices, that bear no lithium battery marking, are exempt from applying STCs and ESCs. This exemption does not apply to packages being sent internationally or to APO/FPO/DPO destinations.
  • These packages must meet the following:
    • Only button cell batteries installed in equipment; or
    • no more than 4 lithium cells; or
    • two lithium batteries installed in the equipment they operate, (e.g., cell phones, tablets, digital readers, or glucose monitors etc.) are not required to bear the lithium battery mark. and
    • when there are no more than two mailpieces in a single consignment, per Pub 52, Section 349.
  • The Federal Register Notice, 87 FR 73459 published on 11/30/2022, required mailers to provide physical separation of HAZMAT/DG from non-HAZMAT/DG packages. Upon full implementation of the electronic indicators on July 9, 2023, mailers may submit a request for a release from the requirement to separate HAZMAT/DG from non-HAZMAT/DG when tendering to the Postal Service. Internal Postal Service data will be utilized to validate compliance with this rule prior to approving customer release of the separation requirement. The requests can be submitted to the Director, Product Classification, 475 L ‘Enfant Plaza, SW Rm 4446, Washington DC 20260-5015.

The final rule recommends mailers to adopt usage of the appropriate ESCs for the type of HAZMAT being shipped, the inclusion of “H” in the Service Box on shipping labels and adding the word “HAZMAT’ within the banner text with the standard Intelligent Mail package barcode (IMpb) for domestic shipments. The final rule also includes the STC and ESC tables for all HAZMAT/DG. Mailers and Customers can find the final rule on the Federal Register website link:

The Postal Service is revising Publication 52, Hazardous, Restricted, and Perishable Mail (Pub 52), to incorporate the new requirements. Although, effective July 9, 2023 and January 21, 2024, the Postal Service will incorporate these revisions into the next edition of Pub 52, which will be available via Postal Explorer at