🔖 This article is part of the Customs Glossary Guide

Hazmat Code (UN/NA Number) Explained

The four-digit identification number used to classify hazardous materials for transport, emergency response, and customs clearance.

Type: UN / NA Number Regulation: 49 CFR 172.101 Usage: Placards & Manifests

What is a Hazmat Code?

A Hazmat Code—technically known as a UN Number or NA Number—is a four-digit identification number assigned to hazardous materials and dangerous goods. It allows first responders, customs officers, and transporters to immediately identify the specific chemical or class of material being transported.

These codes are defined by the United Nations Committee of Experts on the Transport of Dangerous Goods and adopted by the US Department of Transportation (DOT) and Transport Canada.

UN vs. NA Numbers

While often used interchangeably, there is a distinct difference depending on where the goods are moving:

UN Numbers (e.g., UN1203): Valid worldwide. Used for international transport.
NA Numbers (e.g., NA1993): Valid only in the United States and Canada (North America). These are often used for materials not classified as hazardous internationally but regulated domestically (e.g., Combustible Liquids).

The 9 Hazard Classes

The Hazmat Code (UN Number) works in tandem with the Hazard Class. While the UN number identifies the specific substance (e.g., Gasoline), the Class identifies the nature of the risk.

Class	Name	Example (UN Code)
Class 1	Explosives	Dynamite (UN0081)
Class 2	Gases	Propane (UN1978)
Class 3	Flammable Liquids	Gasoline (UN1203)
Class 4	Flammable Solids	Matches (UN1331)
Class 5	Oxidizers	Hydrogen Peroxide (UN2014)
Class 6	Poison / Toxic	Arsenic (UN1558)
Class 7	Radioactive	Uranium (UN2912)
Class 8	Corrosives	Sulfuric Acid (UN1830)
Class 9	Miscellaneous	Lithium Batteries (UN3090)

Using Hazmat Codes in BorderConnect

BorderConnect integrates the complete 49 CFR 172.101 Hazardous Materials Table directly into its eManifest software. This ensures that when carriers enter a UN number, the system automatically validates the data against official US and Canadian regulations.

1. The Integrated Search

When creating a shipment in an ACE or ACI eManifest, users enter the 4-digit code into the Hazmat Code / UN Number field. The system instantly searches the regulatory database:

Input: User types 1203.
Output: BorderConnect auto-populates the Proper Shipping Name (Gasoline), Hazard Class (3), and Packing Group (II).
Benefit: This prevents typos and mismatch errors that typically lead to border penalties.

2. Handling "N.O.S." Entries

If a generic code is used—such as UN1993 (Flammable Liquid, n.o.s.)—Customs regulations require a specific "Technical Name" to be included in the description (e.g., "Contains Ethanol").

BorderConnect Logic: The software recognizes these generic UN codes and prompts the user to add the required technical name in parentheses, ensuring the manifest isn't rejected by the target government system (ACE or ACI).

3. Emergency Contact Requirements

BorderConnect enforces the mandatory requirement for an Emergency Response Contact. When a Hazmat Code is detected on a shipment:

The system unlocks specific fields for the Contact Name (e.g., CHEMTREC) and Phone Number.
The phone number must be monitored 24/7 while the hazardous material is in transit.

Placarding Requirements

In addition to the electronic manifest, the physical truck must display the Hazmat Code if the shipment meets certain weight or volume thresholds.

The Orange Panel

The 4-digit number is typically displayed on an Orange Panel or entered directly onto the white center of the hazard placard. This allows emergency responders to reference the Emergency Response Guidebook (ERG) from a distance during an accident.

Official Resources

PHMSA (DOT): 49 CFR 172.101 Hazmat Table
Transport Canada: Transportation of Dangerous Goods (TDG) Regulations
Emergency Response: 2020 Emergency Response Guidebook (PDF)