USPS HazMat Label Customizations


Loop has made a hazardous materials (HazMat) field for United States Postal Service (USPS) label customizations in Loop admin. The field includes many HazMat product options and customizations, allowing merchants to identify their HazMat products clearly on USPS shipping labels.

You can review more details in EasyPost's USPS Guide.

In this article:

How it works

Merchants must choose which label customization option applies to their products best. The chosen customization will apply to all of that merchant's products. Once the choice is saved, EasyPost will print all the merchant's shipping labels with the customizations, shipping all items as HazMat products.

Important: The default value of the dropdown field is blank and must be changed by the merchant to start using this label customization.

Shipping labels for HazMat packages will have added content such as (see example image below):

  • a service indicator "H" for identification.
  • the words "HAZMAT - Surface Transportation Only" below the return address for surface-only packages.
  • the word "HAZMAT" after "USPS TRACKING #" above the tracking barcode.
Example HazMat USPS label.

HazMat classes

Please review the chart below to choose the best HazMat label customization for your store.

Air eligible ethanol
Air eligible ethanol package
Class 1
Toy propellant/safety fuse package
Class 3
Class 7
Radioactive materials package
Class 8 Corrosive Corrosive materials package

Wet battery Nonspillable wet battery package
Class 9 New lithium individual Lithium battery marked – ground only package

Used lithium Lithium battery – returns package

New lithium device Lithium batteries, marked package

Dry ice Dry ice package

Unmarked lithium Lithium batteries, unmarked package

Magnetized materials package Magnetized materials package
Division 4.1
Mailable flammable solids and safety matches package
Division 5.1
Oxidizers package
Division 5.2
Peroxides package
Division 6.1
Toxic materials package (with an LD50 of 50 mg/kg or less)
Division 6.2
Infectious materials package
Excepted quantity provision
Excepted quantity provision package
Ground only
Ground only
ID8000 consumer commodity package
Lighters package
Limited quantity
Limited quantity ground package
Small quantity provision
Small quantity provision package

Tip: Most of the HazMat examples Loop has seen include lithium batteries, explosives, flammable liquids, flammable solids, compressed gases, and other similar products. If you're unsure whether your product contains HazMat, please review USPS's hazardous materials table. If you don't feel your HazMat products are represented, please reach out to


To select your HazMat label customization, play the video below or review the written instructions beneath it.

  1. In your Loop admin, navigate to Settings > Shipping.
  2. Under "Shipping Services," click Manage Integration next to EasyPost.

    Shipping page in Loop admin with EasyPost shipping service and highlighted "Manage Integration" button for emphasis.
  3. Under "Available Carriers", find USPS and click Edit carrier.

    "Available carriers" section including USPS. USPS's "Edit carrier" button inside red box for emphasis.
  4. Find the HazMat field at the bottom of the "Customize Fields" section.

    HazMat field on the Label Customization page in Loop admin.
  5. To expand the label customization options, click on the "Blank" value box.

    HazMat dropdown field showing current value "Blank."
  6. Click the customization option that fits your products best.

    All possible values for HazMat dropdown field, including Custom Text.
  7. At the top of the page, click Save.

    Highlighted save button at top of browser page.


What if I don't see my store's products on the class table above? You can also check your products against USPS's hazardous materials table for a more extensive list.

How can I find the USPS mailing standards for HazMat? Please visit USPS's page for Publication 52 mailing standards.

Why doesn't this article list other carriers' HazMat classes, regulations, and mailing standards? This customization is not a requirement of other carriers at this time.

How can I make other customizations for shipping labels? Please see our Shipping Label Customizations article!

Please reach out to with any additional questions.

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