Effective November 27, 2025, the Postal Service™ is revising Publication 52, Hazardous, Restricted or Perishable Mail, in various sections, to do the following:
n Correct external regulatory and internal publication references;
n Delete lithium-battery telephone-number marking requirements in the domestic packaging instructions in accordance with new Postal Service standards; and
n Update entries in Appendix A pertaining to lighters and regulated medical waste.
Although these revisions will not be published in Publication 52 until later, these standards are effective immediately.
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Publication 52, Hazardous, Restricted, and Perishable Mail
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3 Hazardous Materials
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34 Mailability by Hazard Class
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348 Corrosives (Hazard Class 8)
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348.2 Mailability
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348.22 Mailable Corrosives
[Revise the text of item b(1) to read as follows:]
(1) Household Dry-Cell Batteries: Common household battery types (AA, AAA, C, D, etc.) are generally not regulated as hazardous materials and are mailable. For nickel-metal hydride batteries in sea transportation, refer to 49 CFR § 172.102, Special Provision 130. Packaging requirements in DMM section 601 apply.
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349 Class 9 Hazardous Materials
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349.2 Lithium Batteries
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349.22 Lithium Batteries — Domestic
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##
349.221 General
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[Revise the note under item d. to read as follows:]
Note: Mailpieces containing button-cell batteries installed in equipment (including circuit boards) or no more than four lithium cells or two lithium batteries installed in the equipment they operate are excepted.
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349.24 Lithium-ion (Rechargeable) Cells and Batteries — Domestic
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349.244 Mailed Without Equipment
[Revise the text of item c. to read as follows:]
c. Marking: Mailpieces must display:
(1) A U.S. Department of Transportation (DOT)-approved lithium-battery mark (see Exhibit 325.4(a)), specifying “UN3480” on the address side.
(2) The text “Surface Mail Only, Secondary Lithium Batteries — Forbidden for Transportation Aboard Passenger Aircraft” or “Surface Mail Only, Lithium-ion Batteries — Forbidden for Transportation Aboard Passenger Aircraft.”
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5 Perishable Matter
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53 Fresh Foods and Other Perishables
[Revise the last sentence of the text of 53 to read as follows:]
***Packaging must meet the requirements in DMM sections 601.1-6.
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Appendix A
Hazardous Materials Table: Postal Service Mailability Guide
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L
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[Revise the text of the entry that begins “Lighters, non-pressurized, containing flammable liquid” in the table in Appendix A to read as follows:]
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R
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[Revise the text of the two entries that begin with “Regulated Medical Waste” in the table in Appendix A to read as follows:]
Regulated medical waste (sharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s.
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6.2
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UN3291
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II
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Prohibited
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6D
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Regulated medical waste (nonsharps), n.o.s. or Clinical waste, unspecified, n.o.s. or (BIO) Medical waste, n.o.s. or Biomedical waste, n.o.s. or Medical waste, n.o.s.
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6.2
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UN3291
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II
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Prohibited
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6E
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Appendix C
USPS Packaging Instructions for Mailable Hazardous Materials
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USPS Packaging Instruction 9D
Lithium Metal and Lithium-ion Cells and Batteries — Domestic
[Revise the text of the first paragraph and the first sentence of the second paragraph to read as follows:]
Lithium metal (nonrechargeable) cells and batteries and lithium-ion (rechargeable) cells and batteries are mailable domestically via air or surface transportation when they are installed in or packed with the equipment they are intended to operate if all the requirements in 349 and this packaging instruction are met.
Unless otherwise excepted, lithium metal and lithium-ion batteries (without equipment) are mailable domestically via surface transportation only.***
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Marking
[Revise the text of the “Marking” section to read as follows:]
Labels and markings must be placed on the address side of the mailpiece unless specified differently in 221.1 and 325.1.
n Lithium metal batteries properly installed in the equipment they are intended to operate:
n Except for mailpieces containing button-cell batteries installed in equipment (including circuit boards), or no more than four lithium metal cells or two lithium metal batteries installed in the equipment they operate, mailpieces containing lithium metal batteries must bear a DOT-approved lithium-battery mark, as specified in 49 CFR 173.185(c)(3)(i) and Exhibit 325.4(a), applied to the address side of the mailpiece.
n The mark must specify “UN3091” for lithium metal cells or batteries installed in equipment.
n Used, damaged, or defective electronic devices (excluding devices that are new in original packaging, and manufacturer-certified new or refurbished devices) must include the text “Restricted Electronic Device” and “Surface Transportation Only” on the address side of the mailpiece.
n Lithium metal batteries packed with the equipment they are intended to operate:
n Mailpieces must bear a DOT-approved lithium-battery mark, as specified in 49 CFR § 173.185(c)(3)(i) and Exhibit 325.4(a), applied to the address side of the mailpiece.
n The mark must specify “UN3091” for lithium metal cells or batteries packed with equipment.
n Used, damaged, or defective electronic devices (excluding devices that are new in original packaging, and manufacturer-certified new or refurbished devices) must include the text “Restricted Electronic Device” and “Surface Mail Only” on the address side on the mailpiece.
n Lithium metal batteries not packed with or installed in equipment (individual batteries):
n Mailpieces must bear a DOT-approved lithium-battery mark, as specified in 49 CFR § 173.185(c)(3)(i) and Exhibit 325.4(a), applied to the address side of the mailpiece.
n The mark must specify “UN3090” for lithium metal cells or batteries.
n Mailpieces must also include the text “Surface Mail Only, Primary Lithium Batteries — Forbidden for Transportation Aboard Passenger Aircraft” or “Surface Mail Only, Lithium Metal Batteries — Forbidden for Transportation Aboard Passenger Aircraft.”
Note: DOT-approved lithium-battery markings must be applied to all mailpieces when there are more than two mailpieces in a single consignment as defined in 349.21(b). If a package contains lithium metal cells or batteries assigned to different UN numbers, all applicable UN numbers must be specified.
n Lithium-ion batteries properly installed in the equipment they are intended to operate:
n Except for mailpieces containing button-cell batteries installed in equipment (including circuit boards), or no more than four lithium-ion cells or two lithium-ion batteries installed in the equipment they operate, mailpieces containing lithium-ion batteries must bear a DOT-approved lithium-battery mark, as specified in 49 CFR § 173.185(c)(3)(i) and Exhibit 325.4(a), applied to the address side of the mailpiece.
n The mark must specify “UN3481” for lithium-ion cells or batteries installed in equipment.
n Used, damaged, or defective electronic devices (excluding devices that are new in original packaging, and manufacturer-certified new or refurbished devices) must include the text “Restricted Electronic Device” and “Surface Mail Only” on the address side on the mailpiece.
n Lithium-ion batteries packed with the equipment they are intended to operate:
n Mailpieces must bear a DOT-approved lithium-battery mark, as specified in 49 CFR § 173.185(c)(3)(i) and Exhibit 325.4(a), applied to the address side of the mailpiece.
n The mark must specify “UN3481” for lithium-ion cells or batteries packed with equipment.
n Used, damaged, or defective electronic devices (excluding devices that are new in original packaging, and manufacturer-certified new or refurbished devices) must include the text “Restricted Electronic Device” and “Surface Mail Only” on the address side on the mailpiece.
n Lithium-ion batteries not packed with or installed in equipment (individual batteries):
n Mailpieces must bear a DOT-approved lithium-battery mark, as specified in 49 CFR § 173.185(c)(3)(i) and Exhibit 325.4(a), applied to the address side of the mailpiece.
n The mark must specify “UN3480” for lithium-ion cells or batteries.
n Mailpieces must also include the text “Surface Mail Only, Secondary Lithium Batteries — Forbidden for Transportation Aboard Passenger Aircraft” or “Surface Mail Only, Lithium-ion Batteries — Forbidden for Transportation Aboard Passenger Aircraft.”
Note: DOT-approved lithium-battery markings must be applied to all mailpieces when there are more than two mailpieces in a single consignment as defined in 349.21(b). If a package contains lithium-ion cells or batteries assigned to different UN numbers, all applicable UN numbers must be specified.
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Appendix G
Hazardous Materials Service Type Codes (STCs) and Extra Service Codes (ESCs)
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STC Domestic Outbound (Required)
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[Revise the text in the table row beginning with “362” to read as follows:]
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The Postal Service will incorporate these revisions into the next edition of the online Publication 52, which is available via Postal Explorer® at pe.usps.com.
— Product Classification,
Product Solutions, 11-27-25
